2003 JOURNAL PAPER Summaries based on PubMed

(2003). "[In Process Citation]." Morfologiia 124(4): 47-50.
 An expression of high molecular component of neurofilament triplet NF200 (marker of neurons forming A-fibers) and binding of isolectin B4 (IB4) was examined immunohistochemically in LIV-LV dorsal root ganglia (DRG) neurons after ligation or transection of the sciatic nerve in rat. NF200 immunoreactivity was detected in 15% of all neurons in DRG of intact rats. Ligation of sciatic nerve caused a two-fold decrease in number of NF200-positive neurons by 90th day after nerve injury, however in animals treated with peripheral nerve regeneration stimulator xymedon the number of surviving NF200-positive neurons was increased by 50.7% as compared with control group (nerve ligation without treatment). In DRG of intact rats 23.6% of neurons showed IB4 binding. Of the DRG neurons 2.6% were labeled by IB4 at 30th day after ligation of the nerve. At 90th day after ligation no IB4-positive neurons were revealed in DRG of untreated rats, while xymedon treatment was shown to result in more than 8-fold increase in the number of surviving IB4-positive neurons. IB4-positive neurons have greater probability of entering the posttraumatic apoptosis. After nerve ligation the survival of NF200- and IB4-positive neurons was less than that one following nerve transection, suggesting that axon lengthening could be a the factor supporting neuronal survival. Pyrimidine derivative xymedon promoted the survival of neurons in both subpopulations with predominant effect on IB4-positive neurons.

(2003). "[In Process Citation]." Morfologiia 124(4): 38-40.
 In the present study the immunohistochemical localization of proline-rich peptide, so called galarmin, was examined in the brain structures of intact and galarmin-treated rats. Galarmin (a fragment of neurophysin II C-end glycopeptide) was isolated by A.A. Galoyan and coworkers in 1997, from the neurosecretory granules of bovine neurohypophysis, produced by the hypothalamic magnocellular nuclei. In intact rats galarmin-immunoreactive neurons and nerve fibers were widely distributed in the central nervous system. Single intramuscular injection of galarmin to the rats resulted in the increase of both galarmin-immunoreactivity and the number of galarmin-immunoreactive nerve cells, fibers and capillaries. In control experiments where the antisera against the fragment of immunophilin (a receptor of immunosuppressor macrolide FK-506) and the pancreatic neuropeptide Y were used as the primary antibodies, the significant increase of neuropeptide Y-immunoreactive nerve fibers and immunophilin-positive lymphocytes was revealed in galarmin-treated rats. Based on these results and the data on the motoneurons regeneration in the spinal cord hemisectioned rats given galarmin daily for 3 weeks, galarmin has been suggested to act as an immunomodulator, neurotransmitter and neuroregulator.

(2003). "Retinal cell rescue: stem cells, remodelling, neuroprotection, apoptosis and replacement of retinal neurons. Proceedings of the 6th Annual Vision Research Conference. Ft. Lauderdale, Florida, USA. May 3-4, 2002." Vision Res 43(8): 857-956.
 
(2003). "Summaries for patients. Nerve growth factor improves healing of pressure ulcers of the foot." Ann Intern Med 139(8): I10.
 
(2003). "[In Process Citation]." Vestn Khir Im I I Grek 162(4): 30-3.
 Experiments in 26 dogs were carried out in order to analyze the quality of comparing the nerve fiber bundles, morphometrical and functional parameters of regeneration after the restoration of the nerve with a standard epineural microsurgical suture and by an original method including the coaptation of the freshened ends by a relaxation transneural suture followed by epiperineural microneurorrhaphy. Five variants of the comparison of the nerve fiber bundles in the suture zone are described. The results of expert assessments and computed morphometry allowed to register higher indices of regeneration and differentiation of nerve fibers.

Aagaard, B. D., D. A. Lazar, et al. (2003). "High-resolution magnetic resonance imaging is a noninvasive method of observing injury and recovery in the peripheral nervous system." Neurosurgery 53(1): 199-203; discussion 203-4.
 OBJECTIVE: Noninvasive observation of degenerating and regenerating peripheral nerves could improve the diagnosis and treatment of nerve injuries. We constructed a novel phased-array radiofrequency coil to permit magnetic resonance imaging (MRI) observation of the sciatic nerve and its target muscles in rats after injury. METHODS: Adult male Lewis rats underwent either crushing (n = 18) or cutting and capping (n = 17) of their right sciatic nerves and then underwent serial MRI. Serial gait track analysis was performed to assess behavioral recovery. Animals from both groups were killed at several time points for histological evaluation of the nerves, with axon counting. RESULTS: Crushed sciatic nerves demonstrated increased T2-weighted signals, followed by signal normalization as axonal regeneration and behavioral recovery occurred. Cut sciatic nerves prevented from regenerating displayed a prolonged phase of increased signal intensity. Acutely denervated muscles exhibited hyperintense T2-weighted signals, which normalized with reinnervation and behavioral recovery. Chronically denervated muscles demonstrated persistently increased T2-weighted signals and atrophy. CONCLUSION: In this study, we demonstrated the ability of MRI to noninvasively monitor injury and recovery in the peripheral nervous system, by demonstrating changes in nerve and muscle that correlated with histological and behavioral evidence of axonal degeneration and regeneration. This study demonstrates the potential of MRI to distinguish traumatic peripheral nerve injuries that recover through axonal regeneration (i.e., axonotmetic grade) from those that do not and therefore require surgical repair (i.e., neurotmetic grade). This diagnostic modality could improve treatment by providing earlier and more accurate diagnoses of nerve damage, as well as reducing the need for exploratory surgery.

Abe, I., A. Tsujino, et al. (2003). "Effect of the rate of prestretching a peripheral nerve on regeneration potential after transection and repair." J Orthop Sci 8(5): 693-9.
 We tested the influence of nerve stretch injury on nerve regeneration after cutting and suturing. An external fixator was used to lengthen the femur, and consequently the sciatic nerve, progressively, by 3 mm/day (5%/day: group I) or 5 mm/day (9%/day: group II). In both groups the total lengthening was 15 mm, corresponding to approximately 23%-28% elongation of the sciatic nerve. Seven days after initiating nerve lengthening, the external fixator was removed and the nerve was transected and sutured. At 2, 4, 6, or 8 weeks after this suturing, semithin sections were prepared from the sciatic and tibial nerves. Although regeneration of nerve fibers was observed beginning at 2 weeks in all groups, nerve regeneration showed a delay only in group II at 6 weeks, when group I showed nerve regeneration as good as in the unstretched control group. Differences in nerve regeneration after nerve lengthening at different rates were considered the result of mechanical nerve injury, nerve degeneration, ischemia, and fibrosis, all made worse with more rapid lengthening. Nerve lengthening at a more moderate rate (3 mm/day) did not appear to compromise regeneration.

Abe, S., I. Mizusawa, et al. (2003). "Changes in mRNA expression patterns for cytokines in blood leukocytes of a rat tourniquet model." Leg Med (Tokyo) 5 Suppl 1: S275-7.
 We examined changes in mRNA expression patterns for proinflammatory cytokines and growth factors in blood samples after application of a tourniquet to the rat hind limb. Slight upregulations of interferon (IFN)-gamma, macrophage colony-stimulating factor (M-CSF) and transforming growth factor (TGF)-beta1 mRNA began at 2h after tourniquet application and were short-lived. The levels of activating transcription factor (ATF)-3, a stress-inducible gene, had increased at 1h after tourniquet application. No significant expression of interleukin (IL)-6 mRNA was observed in most samples. There were no significant temporal changes in the levels of IL-1beta, cardiotrophin (CT)-1 mRNA compared to the control levels, but, downregulation of gp130, a receptor of the IL-6 family, began at 1h after tourniquet application. Nerve growth factor (NGF) mRNA gradually increased and reached a significantly high level at 4h after application of the tourniquet. Gene expression induction in blood leukocytes occurred soon after application of the tourniquet and was short-lived. The transient mRNA expressions probably trigger secondary events that may be beneficial to wound repair and regeneration.

Abrams, C. K., M. Freidin, et al. (2003). "Pathogenesis of X-linked Charcot-Marie-Tooth disease: differential effects of two mutations in connexin 32." J Neurosci 23(33): 10548-58.
 X-linked Charcot-Marie-Tooth disease is an inherited peripheral neuropathy arising in patients with mutations in the gene encoding connexin 32 (Cx32). Cx32 is expressed at the paranodes and Schmidt-Lantermann incisures of myelinating Schwann cells in which it is believed to form a reflexive pathway between the abaxonal and adaxonal cytoplasmic domains. Patients with the Val181Ala (V181A) mutation have a severe peripheral neuropathy. Experiments using a nude mouse xenograft system show that Schwann cells expressing only this mutant form of Cx32 are profoundly impaired in their ability to support the earliest stages of regeneration of myelinated fibers. Coupling between paired Xenopus oocytes expressing V181A is reduced compared with the coupling between oocytes expressing wild-type human Cx32 (32WT), and protein levels assayed by Western blot are substantially lower. Immunocytochemisty shows that Neuro2a cells expressing the V181A mutant have very few gap junction plaques compared with cells expressing 32WT; Cx32 protein levels are lower in these cells than in those expressing 32WT. Because failure of normal regeneration is evident before formation of myelin, loss of function of Cx32 may impact on the function of precursors of the myelinating Schwann cell before the formation of the hypothesized reflexive pathway. The Glu102Gly (E102G) mutation leads to a milder phenotype. Early regeneration is normal in grafts with Schwann cells expressing the E102G mutant. The only abnormality detected in the behavior of its channel is increased sensitivity to acidification-induced closure, a property that may lead to reduced gap junction coupling during periods of metabolic stress. This restricted functional abnormality may explain the relatively mild phenotype seen in the xenograft model and in E102G patients.

Ackermann, P. W., J. Li, et al. (2003). "Neuronal plasticity in relation to nociception and healing of rat achilles tendon." J Orthop Res 21(3): 432-41.
 Nerve regeneration and the occurrence of three neuropeptides; i.e. substance P (SP), calcitonin gene related peptide (CGRP) and galanin (GAL), were studied during healing of tendon rupture in the rat by semi-quantitative immunohistochemistry. The neuronal findings were related to nociception as assessed by hindpaw withdrawal latencies at thermal and mechanical tests.Experimental rupture of rat Achilles tendon--normally devoid of nerves--elicited extensive nerve ingrowth into the rupture site in the early phase of healing followed by almost complete fiber disappearance (weeks 12-16). The ingrowth of SP and CGRP positive fibers, seen already at weeks 1-2, was associated with increased nociception. Subsequently, the occurrence of GAL positive fibers at weeks 4-6 was associated with decreased nociception. An even stronger relationship to nociception during healing was observed when the rate of change in neuropeptide expression instead of the expression in absolute terms was considered, according to the "cascade" formula of SP(')+CGRP(')-GAL(').It may prove that the observed temporal occurrence of different neuropeptides reflects a role of the peripheral nervous system in regulating synchronously nociception and healing.

Adams, D. S., B. Hasson, et al. (2003). "A peptide fragment of ependymin neurotrophic factor uses protein kinase C and the mitogen-activated protein kinase pathway to activate c-Jun N-terminal kinase and a functional AP-1 containing c-Jun and c-Fos proteins in mouse NB2a cells." J Neurosci Res 72(3): 405-16.
 Ependymin (EPN) is a goldfish brain neurotrophic factor previously shown to function in a variety of cellular events related to long-term memory formation and neuronal regeneration. CMX-8933, an 8-amino-acid synthetic peptide fragment of EPN, was designed for aiding an investigation of the biological properties of this glycoprotein. We reported from previous studies that treatment of mouse neuroblastoma (NB2a) cultures with CMX-8933 promotes activation of transcription factor AP-1, a characteristic previously associated with the following full-length neurotrophic factors: nerve growth factor, neurotropin-3, and brain-derived neurotrophic factor. The CMX-8933-activated AP-1 specifically bound an AP-1 consensus probe and appeared to contain c-Jun and c-Fos protein components in antibody supershift experiments. Because AP-1 influences a variety of positive and negative cellular processes, determined in part by its exact protein composition and mechanism of activation, we extended these initial AP-1 observations in the current study to confirm the identity of the CMX-8933-activated c-Jun and c-Fos components. CMX-8933 increases the enzymatic activity of c-Jun N-terminal kinase (JNK), increases the phosphorylation of JNK and c-Jun proteins, and increases the cellular titers of c-Jun and c-Fos mRNAs. Furthermore, the AP-1 activated by CMX-8933 is functional, insofar as it transactivates both synthetic and natural AP-1-dependent reporter plasmids. Inhibition studies indicate that activation of the 8933-induced AP-1 occurs via the mitogen-activated protein kinase pathway. These data are in agreement with the recently proposed model for the conversion of short- to long-term synaptic plasticity and memory, in which a JNK-activated transcription factor AP-1, containing c-Jun and c-Fos components, functions at the top of a hierarchy of transcription factors known to regulate long-term neural plasticity.

Adanali, G., M. Verdi, et al. (2003). "Effects of hyaluronic acid-carboxymethylcellulose membrane on extraneural adhesion formation and peripheral nerve regeneration." J Reconstr Microsurg 19(1): 29-36.
 The goal of nerve repair in the peripheral nervous system is to increase the number of axons passing from proximal to distal stump, and to enable the regenerated axons to reach the end organ as soon as possible. In the present study, the effect of the membrane formed by a mixture of hyaluronic acid and carboxymethylcellulose (HA-CMC) on nerve regeneration and perineurial scar formation was investigated. Eighteen New Zealand rabbits were allocated into control (n = 9) and experimental groups (n = 9). In the control group, conventional nerve repair was carried out following the transection of the sciatic nerve, while in the experimental group, following repair of the nerve, the repair line was covered by HA-CMC membrane extending 1 cm beyond the distal and proximal ends. Nerve regeneration and extraneurial adhesion formation were compared between the two groups 3 months later. It was observed that adhesion in the surrounding tissues was significantly less in the experimental group than in the control group. Furthermore, morphometric analysis of specimens obtained from the distal parts of nerves showed that the number of axons with myelin was higher in the experimental group than in the control group, with a statistically significant difference. Histologic sections obtained from the nerve repair line demonstrated that extraneural and intraneural fibrosis was significantly lower in the experimental group. It was concluded that HA-CMC membrane had a favorable effect on nerve regeneration, as well as extraneural scar formation, encouraging the clinical application of HA-CMC following nerve injuries.

Adams, M. (2003). "Third annual meeting of the California Spinal Cord Injury/Neural Regeneration Consortium March 20-21, 2002, the Reeve-Irvine Research Center of the University of California, Irvine, USA." Spinal Cord 41(2): 134-6.
 
Adani, R., I. Marcoccio, et al. (2003). "Flap coverage of dorsum of hand associated with extensor tendons injuries: A completely vascularized single-stage reconstruction." Microsurgery 23(1): 32-9.
 This study reports results in 12 patients treated with "completely vascularized single-stage approaches," so defined because skin, tendon, and nerve are transferred as a compound flap, and all are vascularized. A free dorsalis pedis cutaneotendinous flap was used in 7 patients, while a radial forearm cutaneotendinous island flap was transposed in 5 patients. A dorsalis pedis flap provides four vascularized extensor tendons (extensor digitorum comunis tendons), and the radial artery flap permits the inclusion of one completely vascularized tendon (palmaris longus) and two "strips" of vascularized tendons (flexor carpi radialis and brachioradialis). The flaps survived in all cases, and the transferred tendons were functioning well. The dorsalis pedis flap can be employed in the reconstruction of cutaneotendinous defects of the dorsum of the hand which require the use of three or four tendons grafts. We suggest the use of forearm cutaneotendinous flaps in cases of reconstruction of one or two extensor tendons. The "completely vascularized single-stage reconstruction" avoids prolonged hospitalization and results in a rapid restoration of near-normal function and appearance of the hand.

Agbulut, O., M. L. Menot, et al. (2003). "Temporal patterns of bone marrow cell differentiation following transplantation in doxorubicin-induced cardiomyopathy." Cardiovasc Res 58(2): 451-9.
 OBJECTIVE: Recent studies have suggested benefits of bone marrow cell transplantation for the regeneration of ischemic cardiac tissue. To extend the potential of cell transplantation, we assessed this treatment in a mouse model of acute nonischemic doxorubicin-induced cardiomyopathy. METHODS: To allow detection of engrafted cells, we used transgenic mice expressing the nuclear-located LacZ under the control of either desmin or vimentin promoters, which identify muscle lineage and mesenchymal cells, respectively. All transplanted cells were also labeled with the fluorescent dye DIL. One week after the administration of doxorubicin (15 mg/kg), mice were intramyocardially injected with either allogeneic unpurified bone marrow cells (6 x 10(6) in 30 microl, n=59) or purified sca-1(pos) cells (4 x 10(5) in 30 microl, n=22). In parallel, control normal mice received only unpurified bone marrow cells (n=28). Hearts were harvested at serial intervals until 2 weeks after transplantation and analyzed by immunohistochemistry to assess the degree of engraftment and transplanted cell differentiation. RESULTS: In control mice, no differentiation of bone marrow cells was detected. In contrast, unpurified bone marrow cells grafted into diseased myocardium featured two successive phases of cell differentiation. The first yielded cells with a mesenchymal phenotype (44.1+/-10.1 cells/3 x 10(-2) mm(3) at 2 days), was transient and lasted 1 week. The second phase was characterized by cells with a muscular phenotype detected in a small number of cells (5.6+/-2.3 cells/3 x 10(-2) mm(3) at 7 days). Two weeks after transplantation, some of these cells appeared phenotypically close to cardiomyocytes, as evidenced by morphology and positive staining for myosin binding protein C, vinculin and myosin heavy chain. In sca-1(pos) hematopoietic progenitor grafted mice hearts, no transdifferentiation into cardiac cells was detected at any time point. CONCLUSION: These data support the hypothesis of the potential for a myogenic differentiation of bone marrow cells following engraftment in a nonischemic model of global cardiomyopathy. Bone marrow-derived cells amenable to cardiac differentiation are present in total unpurified bone marrow but not in the sca-1(pos) hematopoietic progenitor cell population. However, the very small number of transdifferentiated cells raises concerns over their functional efficacy.

Ahmed, Z., S. Underwood, et al. (2003). "Nerve guide material made from fibronectin: assessment of in vitro properties." Tissue Eng 9(2): 219-31.
 We have previously used orientated mats of fibronectin as conduits to repair short gaps in peripheral nerves. Here we describe the in vitro properties of a new material in the form of large cables produced from a fibronectin-enriched solution with potential as a conduit for longer nerve defects. Large cables of fibronectin were made up to 14 cm long x 1.5 cm in diameter. When freeze dried, scanning electron microscopy revealed a predominant fiber orientation. Dried cables hydrated rapidly to 1.6 and 4.8 times their original length and diameter, respectively. Once hydrated these cables had pores that ranged from 10 to 100 microm through which Schwann cells and fibroblasts were able to grow in vitro and align with the axis of the fibrils by contact guidance. Furthermore, the porosity of the cable was enhanced by the natural dissolution of protein over a 3-week duration in culture with cells, such that 50- to 200-microm pores were observed. This study suggests that large fibronectin cables are a suitable alternative to the original fibronectin mats to guide components of the peripheral nerves and so to act as conduits with potential use in guiding regeneration across long nerve defects.

Akassoglou, K., P. Akpinar, et al. (2003). "Fibrin is a regulator of Schwann cell migration after sciatic nerve injury in mice." Neurosci Lett 338(3): 185-8.
 Fibrin, derived from the blood protein fibrinogen, is deposited in the sciatic nerve after injury and retards functional regeneration. Since Schwann cell migration is critical for remyelination of injured nerves, we investigated the effects of fibrin in this process. In vivo experiments showed that fibrin co-localizes with fibronectin deposition in the injured sciatic nerve. In vitro migration assays demonstrated that fibrin alone is not a permissive substrate for Schwann cell migration. Furthermore, migration assays of Schwann cells on mixed fibrin/fibronectin substrates showed that fibrin has a dose dependent inhibitory effect on Schwann cell migration on fibronectin. Our results show that fibrin, deposited in the sciatic nerve after injury, changes the composition of the extracellular matrix and inhibits Schwann cell migration. This negative effect of fibrin should be considered in the therapeutic application of biomaterials based on fibrin matrices.

Allegretto, M., M. Morrison, et al. (2003). "Selective denervation: reinnervation for the control of adductor spasmodic dysphonia." J Otolaryngol 32(3): 185-9.
 OBJECTIVES: The objective of this study was to evaluate the efficacy of a new surgical procedure for adductor spasmodic dysphonia (AddSD). This surgery involves the bilateral selective division of the adductor branches of the recurrent laryngeal nerves with immediate reinnervation of the distal nerve trunks with branches of the ansa cervicalis (selective denervation-reinnervation). METHODS: Our first six patients to undergo this procedure were enrolled in the study. All patients suffered from AddSD and had previously received botulinum toxin A (Botox, Allergen, Markham, ON) therapy. Patients were recorded preoperatively and all underwent the same surgical procedure performed by the same lead surgeon. All patients were surveyed postoperatively and then re-recorded. Expert and untrained judges undertook perceptual evaluation of voice quality. Voice samples were also objectively evaluated for aphonic voice breaks. RESULTS: No major surgical complications were noted. Patient satisfaction was excellent, and five of the six patients no longer require botulinum toxin therapy. In five of the six patients, the majority of untrained and expert listeners perceived the postoperative voice to be superior. Objectively, the rate of aphonic voice breaks was also reduced in five of the six patients.

Alsancak, S. (2003). "Splint satisfaction in the treatment of traumatic radial nerve injuries." Prosthet Orthot Int 27(2): 139-45.
 Between the years 1986-2001, 135 patients who have had traumatic radial nerve injury, were supplied with dynamic wrist-hand orthoses (WHOs). The aim of this study is to examine the applied splints, considering aspects such as apperance, practicality of use, function, comfort and endurance. The author's assessments show that the biggest problem was due to the unaesthetic appearance of the finger extensor spring of the splints. For this reason, modification of these finger extensor outriggers has been attempted. Also, aspects of the splints such as the problems faced and regeneration of the nerve, have been considered and modifications made in order to eliminate any disfunction. This study reflects the reactions and satisfaction of 83 patients concerning the splints they have used. Conventional wire springs have been used in the splints of 71 patients, and 12 had modifications done on their outriggers. In terms of appearance, there were significant differences between modified outriggers and conventional outrigger (p < 0.05). Also, when the modified outriggers were compared in terms of appearance and durability, there was a statistically significant opinion in favour of them (p < 0.01).

Amer, R. K., C. R. Pace-Asciak, et al. (2003). "A lipoxygenase product, hepoxilin A(3), enhances nerve growth factor-dependent neurite regeneration post-axotomy in rat superior cervical ganglion neurons in vitro." Neuroscience 116(4): 935-46.
 Hepoxilins are 12-lipoxygenase metabolites of arachidonic acid found in the CNS. They can modulate neuronal signaling but their functions are not known. We examined the effects of hepoxilin A(3) on neurite outgrowth post-axotomy in an in vitro model of spinal cord transection using superior cervical ganglion neurons. In the absence of nerve growth factor, hepoxilin A(3) did not support neuronal survival, or regeneration post-axotomy but did significantly enhance neurite regeneration in the presence of nerve growth factor. As early as 1 h post-injury hepoxilin A(3)-treated cultures (+nerve growth factor) had significantly more neurites than controls (nerve growth factor alone). Average hourly rates of outgrowth in hepoxilin A(3)-treated cultures were significantly higher than in controls for at least 12 h post-injury, suggesting that the effect of hepoxilin A(3) is maintained in vitro for several hours post-injury. In uninjured neurons hepoxilin A(3) caused a rapid but transient increase in intracellular calcium in the somata; by 2 min post-addition, calcium levels decreased to a new stable plateau significantly higher than pre treatment levels. In injured neurons, hepoxilin A(3) addition immediately post-transection caused a rapid transient increase in intracellular calcium in cell bodies; however, peak calcium levels were significantly lower than in uninjured neurons and the new baseline lower than in uninjured cells. In uninjured cells hepoxilin A(3) addition in zero calcium produced the same pattern, a transient elevation and subsequent decline to a new stable baseline significantly above rest but in injured cells levels fell rapidly to pretreatment values. Taken overall, these findings demonstrate a novel role for hepoxilins as a potentiator of neurite regeneration. They also provide the first evidence that this lipoxygenase metabolite can alter intracellular calcium in neurons by causing release of calcium from intracellular stores and modulating calcium influx mechanisms.

Anderson, K. D., M. A. Merhege, et al. (2003). "Increased expression and localization of the RNA-binding protein HuD and GAP-43 mRNA to cytoplasmic granules in DRG neurons during nerve regeneration." Exp Neurol 183(1): 100-8.
 The neuronal-specific RNA-binding protein, HuD, binds to a U-rich regulatory element of the 3' untranslated region (3' UTR) of the GAP-43 mRNA and delays the onset of its degradation. We have recently shown that overexpression of HuD in embryonic rat cortical cells accelerated the time course of normal neurite outgrowth and resulted in a twofold increase in GAP-43 mRNA levels. Given this evidence, we sought to investigate the involvement of HuD during nerve regeneration. It is known that HuD protein and GAP-43 mRNA are expressed in the dorsal root ganglia (DRG) of adult rat and that GAP-43 is upregulated in DRG neurons during regeneration. In this study, we examined the expression patterns and levels of HuD and GAP-43 mRNA in DRG neurons following sciatic nerve injury using a combination of in situ hybridization, immunocytochemistry, and quantitative RT-PCR. GAP-43 and HuD expression increased in the ipsilateral DRG during the first 3 weeks of regeneration, with peak values seen at 7 days postcrush. At this time point, the levels of HuD and GAP-43 mRNAs in the ipsilateral DRG increased by twofold and sixfold, respectively, relative to the contralateral DRG. Not only were the temporal patterns of expression of HuD protein and GAP-43 mRNA similar, but also they were found to colocalize in the cytoplasm of DRG neurons. Moreover, both molecules were distributed in cytoplasmic granules containing ribosomal RNA. In conclusion, our results suggest that HuD is involved in the upregulation of GAP-43 expression observed at early stages of peripheral nerve regeneration.

Andre, S., H. Boukhaddaoui, et al. (2003). "Axotomy-induced expression of calcium-activated chloride current in subpopulations of mouse dorsal root ganglion neurons." J Neurophysiol 90(6): 3764-73.
 Whole cell patch-clamp recordings of calcium-activated chloride current [ICl(Ca)] were made from adult sensory neurons of naive and axotomized mouse L4-L6 lumbar dorsal root ganglia after 1 day of culture in vitro. A basal ICl(Ca) was specifically expressed in a subset of naive medium-diameter neurons (30-40 microm). Prior nerve injury, induced by sciatic nerve transection 5 days before experiments, increased both ICl(Ca) amplitude and its expression in medium-diameter neurons. Moreover, nerve injury also induced ICl(Ca) expression in a new subpopulation of neurons, the large-diameter neurons (40-50 microm). Small-diameter neurons (inferior to 30 microm) never expressed ICl(Ca). Regulated ICl(Ca) expression was strongly correlated with injury-induced regenerative growth of sensory neurons in vitro and nerve regeneration in vivo. Cell culture on a substrate not permissive for growth, d,l-polyornithine, prevented both elongation growth and ICl(Ca) expression in axotomized neurons. Regenerative growth and the induction of ICl(Ca) expression take place 2 days after injury, peak after 5 days of conditioning in vivo, slowly declining thereafter to control values. The selective expression of ICl(Ca) within medium- and large-diameter neurons conditioned for rapid, efficient growth suggests that these channels play a specific role in postinjury behavior of sensory neuron subpopulations such as neuropathic pain and/or axonal regeneration.

Andre, S., S. Puech-Mallie, et al. (2003). "Axotomy differentially regulates voltage-gated calcium currents in mice sensory neurones." Neuroreport 14(1): 147-50.
 Medium sized dorsal root ganglion neurones are involved in tactile sensation and responsible for allodynia following nerve injury. We examined the effects of sciatic nerve injury on the expression of low and high voltage-gated calcium currents in medium sized neurones isolated from lumbar dorsal root ganglia of adult mice. Based on the relative expression of these calcium channel types, three populations of medium sized neurones were identified in controls. Type I, II and III populations were characterised respectively by small, predominant and no low voltage-gated current compared to the high voltage-gated current. Five days after nerve injury, calcium current expression was differentially affected by axotomy in these three subsets of medium neurones. Altogether, these results suggest that calcium channels are heterogeneously distributed among the medium sized neurones. This heterogeneity should provide specificity not only to sensory functions but also to sensory responses following nerve injury.

Andrews, R. J. (2003). "Neuroprotection trek--the next generation: neuromodulation II. Applications--epilepsy, nerve regeneration, neurotrophins." Ann N Y Acad Sci 993: 14-24; discussion 48-53.
 Three examples of neuroprotective applications of electrical stimulation-neuromodulation-are considered: (1) the diagnosis and treatment of epilepsy, (2) the augmentation of peripheral nerve regeneration after transection, and (3) the interaction between electrical stimulation and neurotrophins (notably brain derived neurotrophic factor [BDNF]) in various neuroprotective situations. The research cited demonstrates clear benefit from appropriate electrical stimulation in the treatment of (1) certain patients with medication-refractory epilepsy, and (2) the functional regeneration of peripheral nerves after transection and surgical repair. Furthermore, neuromodulation of peripheral nerve regeneration has been associated with an increase in the neurotrophin BDNF. The roles of BDNF and other neurotrophins in several disorders of the nervous system are discussed in the context of neuromodulation and its augmentation of neurotrophins. Neuromodulation-at least in part through its effect on BDNF and other neurotrophins-will likely play a major role in the treatment (and possibly prevention) of disorders of the nervous system for which neuroproteive pharmacologic agents have traditionally been sought.

Arlotta, P., S. S. Magavi, et al. (2003). "Induction of adult neurogenesis: molecular manipulation of neural precursors in situ." Ann N Y Acad Sci 991: 229-36.
 Over most of the past century, it was thought that the adult brain was completely incapable of generating new neurons. However, in the last decade, the development of new techniques has resulted in an explosion of new research showing that (i) neurogenesis, the birth of new neurons, is not restricted to embryonic development, but normally also occurs in two limited regions of the adult mammalian brain (the olfactory bulb and the dentate gyrus of the hippocampus); (ii) that there are significant numbers of multipotent neural precursors in many parts of the adult mammalian brain; and (iii) that it is possible to induce neurogenesis even in regions of the adult mammalian brain, like the neocortex, where it does not normally occur, via manipulation of endogenous multipotent precursors in situ. In the neocortex, recruitment of small numbers of new neurons can be induced in a region-specific, layer-specific, and neuronal type-specific manner, and newly recruited neurons can form long-distance connections to appropriate targets. This suggests that elucidation of the relevant molecular controls over adult neurogenesis from endogenous neural precursors/stem cells may allow the development of neuronal replacement therapies for neurodegenerative disease and other central nervous system injuries that may not require transplantation of exogenous cells.

Arlotta, P., S. S. Magavi, et al. (2003). "Molecular manipulation of neural precursors in situ: induction of adult cortical neurogenesis." Exp Gerontol 38(1-2): 173-82.
 Over the past three decades, research exploring potential neuronal replacement therapies have focused on replacing lost neurons by transplanting cells or grafting tissue into diseased regions of the brain. Over most of the past century of modern neuroscience, it was thought that the adult brain was completely incapable of generating new neurons. However, in the last decade, the development of new techniques has resulted in an explosion of new research showing that neurogenesis, the birth of new neurons, normally occurs in two limited and specific regions of the adult mammalian brain, and that there are significant numbers of multipotent neural precursors in many parts of the adult mammalian brain. Recent findings from our lab demonstrate that it is possible to induce neurogenesis de novo in the adult mammalian brain, particularly in the neocortex where it does not normally occur, and that it may become possible to manipulate endogenous multipotent precursors in situ to replace lost or damaged neurons. Recruitment of new neurons can be induced in a region-specific, layer-specific, and neuronal type-specific manner, and newly recruited neurons can form long-distance connections to appropriate targets. Elucidation of the relevant molecular controls may both allow control over transplanted precursor cells and potentially allow the development of neuronal replacement therapies for neurodegenerative disease and other CNS injuries that do not require transplantation of exogenous cells.

Armstrong, J., L. Zhang, et al. (2003). "Axonal regeneration of descending and ascending spinal projection neurons in spinal cord-transected larval lamprey." Exp Neurol 180(2): 156-66.
 The distributions of descending and ascending spinal projection neurons (i.e., spinal neurons with moderate to long axons) were compared in normal larval lamprey and in animals that had recovered for 8 weeks following a complete spinal cord transection at 50% body length (BL, normalized distance from the anterior head). In normal animals, application of HRP to the spinal cord at 60% BL (40% BL) labeled an average of 713.8 +/- 143.2 descending spinal projection neurons (718.4 +/- 108.0 ascending spinal projection neurons) along the rostral (caudal) spinal cord, most of which were unidentified neurons. Some of these neurons project for at least approximately 50-60 spinal cord segments (approximately 36-47 mm in animals with an average length of approximately 90 mm used in the present study). At 8 weeks posttransection, the numbers of HRP-labeled descending or ascending spinal neurons that extended their axons through the transection were about 40% of those in similar areas of the spinal cord in normal animals. Thus, in larval lamprey, axonal regeneration of descending and ascending spinal projection neurons is incomplete, similar to that found for descending brain neurons. The majority of restored projections were from unidentified spinal neurons that have not been documented previously. In contrast to results from several other lower vertebrates, in the lamprey ascending spinal neurons exhibited substantial axonal regeneration. Identified descending spinal neurons, such as lateral interneurons and crossed contralateral interneurons, and identified ascending spinal neurons, such as giant interneurons and edge cells, regenerated their axons at least 9 mm beyond the transection site in animals with an average length of approximately 90 mm, which is appreciably farther than previously reported. In contrast, most dorsal cells, which are centrally located sensory neurons, exhibited very little axonal regeneration.

Au, E. and A. J. Roskams (2003). "Olfactory ensheathing cells of the lamina propria in vivo and in vitro." Glia 41(3): 224-36.
 Olfactory ensheathing cells (OECs) continuously support the regeneration of olfactory receptor neurons (ORNs). In addition, OECs promote regeneration of neurons within the CNS in a number of transplantation paradigms, but details of exactly how they support regeneration remain elusive. The majority of studies using OECs to promote regeneration have thus far focused on understanding the cell biology of OECs purified from the olfactory bulb (OB). Here we show that a population of OECs similar to those obtained from the OB is present in the lamina propria (LP) beneath the olfactory epithelium (OE). These OECs are the first glial cells encountered by the axons of developing ORNs as they exit the OE and display distinct and variable expression of p75, S100beta, GFAP, and O4, characteristic markers of bulb OECs. Once purified in vitro, they display Schwann cell-like and astrocyte-like properties and expand rapidly. In addition to resembling OB-OECs, LP-OECs also express a unique combination of developmentally important proteins-CD 44, beta1 integrin, P200, Notch 3, NG2, VEGF, and PACAP and CREB binding protein (CBP/p300)-not previously reported in OB-OECs. These data suggest that LP-OECs, like OB-OECs, are a developmentally distinct class of glia that are capable of both immature and mature function, depending on environmental stimuli, within the adult nervous system.

Auld, D. S. and R. Robitaille (2003). "Perisynaptic Schwann cells at the neuromuscular junction: nerve- and activity-dependent contributions to synaptic efficacy, plasticity, and reinnervation." Neuroscientist 9(2): 144-57.
 Glial cells are increasingly recognized for their important contributions to CNS and PNS synaptic function. Perisynaptic Schwann cells, which are glial cells at the neuromuscular junction, have proven to be an exceptionally useful model for studying these roles. Recent studies have shown that they detect and reciprocally modulate synaptic efficacy in an activity-dependent manner in the short term. In addition, perisynaptic Schwann cells guide reinnervating nerve sprouts after deinnervation, and many important parameters of this are dependent on synapse activity. Thus, it is hypothesized that perisynaptic Schwann cells are key integrators in a continuum of synaptic efficacy, stability, and plasticity at the neuromuscular junction, which is important for maintaining and restoring synaptic efficacy.

Avramut, M. and C. L. Achim (2003). "Immunophilins in nervous system degeneration and regeneration." Curr Top Med Chem 3(12): 1376-82.
 Immunophilins are receptors for immunosuppressive drugs like cyclosporin A, FK506, rapamycin and their non- immunosuppressive analogs, which are collectively referred to as "immunophilin ligands" (IPL). Cyclosporin A binds to a class of IP called cyclophilins, whereas the receptors for FK506 and rapamycin belong to the family of FK506- binding proteins (FKBP). The latter are designated according to their molecular weight: FKBP12, 25, 52 etc. FKBP levels in the rat brain are up to 50 times higher than in the immune system. FKBP12 is associated with IP3 and ryanodine receptors present on the endoplasmic reticulum and plays a role in stabilizing calcium release. It has also been proposed to be a modulator of the TGFbeta receptor activity. Crush injury of facial or sciatic nerves in rat leads to markedly increased FKBP12 levels in the respective nerve nuclei and this increase is related to nerve regeneration. Cyclophilin A protects cells from death following expression of mutant Cu/ Zn superoxide dismutase, which is associated with familial amyotrophic lateral sclerosis. Our recent studies show that FKBP12 and FKBP52 are expressed in the human nervous system, especially in the substantia nigra- deep gray matter axis. In neurodegenerative diseases, FKBP12 levels increase in neurons situated in areas of pathology. This IP colocalizes with synaptophysin and alpha- synuclein, suggesting that it may become a novel marker of pathology. Immunophilins participate in axonal transport, synaptic vesicle assembly and may play a role in neuroprotection against abnormal protein aggregation, suggesting a potential avenue of therapeutic interventions.

Ayhan, S., N. Markal, et al. (2003). "Effect of subepineurial dehydroepiandrosterone treatment on healing of transected nerves repaired with the epineurial sleeve technique." Microsurgery 23(1): 49-55.
 The epineurial sleeve technique for nerve repair is designed in part to protect a healing nerve from external humoral influences, but research suggests that the external factor dehydroepiandrosterone (DHEA) may actually improve nerve healing in crush injuries. To test the effect of DHEA, we injected it into the epineurial chambers created to repair transected rat sciatic nerves. In 18 control rats, the nerve was transected and repaired without DHEA treatment. Eighteen animals received subepineurial injections of propylene glycol vehicle, and 18 received subepineurial injections of about 0.2 ml DHEA. Walking-track analysis and toe-contracture measurements showed no significant differences among the three groups. At 12 weeks, the gastrocnemius muscles in the DHEA group were significantly heavier than those of untreated controls. At 6 and 12 weeks, DHEA-treated nerves had significantly more myelinated axons, larger average fiber diameter, and greater axonal cross-sectional areas in the proximal, middle, and distal sections. Myelin thickness did not differ between groups, except at 6 weeks between the DHEA and vehicle-treated groups. We conclude that subepineurial dehydroepiandrosterone treatment reduced the extent of denervation atrophy and induced an earlier onset of axonal regeneration.

Bacakoglu, A., M. H. Ozkan, et al. (2003). "Forearm arterial vein grafting: problems and alternative solutions." J Int Med Res 31(5): 458-65.
 We aimed to evaluate patency rates following forearm arterial reconstruction and suggest improvements. Thirty-two vein grafted reconstructions (using saphenous and dorsal hand veins) were evaluated for patency and development of symptoms using clinical examination, Colour-Doppler Sonography and angiography. Overall patency was 59%, with no significant difference between saphenous and dorsal hand veins. Stasis, turbulence, decrease in blood velocity, change in flow pattern, stenosis in the anastomotic area or increase in compliance was detected in 10 patent grafts, but was not associated with symptoms. Six out of 13 non-patent grafted patients had severe or troublesome symptoms associated with accompanying nerve regeneration. To improve patency, careful microsurgical techniques, 'fit vein' and valveless grafts should be used. Dorsal hand veins are most appropriate for short defects. Patency should be evaluated soon after reconstruction.

Bach-y-Rita, P. (2003). "Theoretical basis for brain plasticity after a TBI." Brain Inj 17(8): 643-51.
 Evidence has been accumulating that the brain can reorganize extensively after damage and that reorganization can be obtained even many years after the trauma with appropriate late rehabilitation. An understanding of the brain plasticity mechanisms should lead to more effective rehabilitation and neuropharmacology. In this communication, several emerging concepts with supporting experimental evidence have been presented. These include non-synaptic diffusion neurotransmission, extracellular space volume fraction, neurotransmitters, regeneration and neurogenesis and multiplexing.

Bach, H., D. A. Feldheim, et al. (2003). "Persistence of graded EphA/Ephrin-A expression in the adult frog visual system." J Comp Neurol 467(4): 549-65.
 Many studies have demonstrated the involvement of the EphA family of receptor tyrosine kinases and their ligands, ephrin-A2 and -A5, in the development of the temporonasal axis of the retinotectal/collicular map, but the role of these molecules in optic nerve regeneration has not been well studied. Noting that the characteristic gradients of the EphA/ephrin-A family that are expressed topographically in the retina and tectum of embryonic chicks and mice tend to disappear after birth, we took as our starting point an analysis of EphA and ephrin-A expression in leopard frogs (Rana pipiens and utricularia), species capable of regenerating the retinotectal map as adults. For the EphA family to be involved in the regeneration, one would expect these topographic gradients to persist in the adult or, if downregulated after metamorphosis, to be reexpressed after optic nerve injury. Using EphA3 receptor and ephrin-A5 ligand alkaline phosphatase in situ affinity probes (RAP and LAP, respectively) in whole-mount applications, we report that reciprocally complementary gradients of RAP and LAP binding persist in the optic tract and optic tectum of postmetamorphic frogs, including mature adults. EphA expression in temporal retinal axons in the optic tract was significantly reduced after nerve section but returned during regeneration. However, ephrin-A expression in the tectal parenchyma was not significantly elevated by either eye removal, with degeneration of optic axons, or during regeneration of the retinotectal projection. Thus, the present study has demonstrated a persisting expression of EphA/ephrin-A family members in the retinal axons and tectal parenchyma that may help guide regenerating fibers, but we can offer no evidence for an upregulation of ephrin-A expression in conjunction with optic nerve injury.

Balkowiec-Iskra, E., I. Kurkowska-Jastrzebska, et al. (2003). "Post intoxicative therapeutic immunization with myelin oligodendrocyte glycoproteine (MOG 35-55) suppresses spontaneous regeneration of dopaminergic neurons injured with 1-methyl-4 phenyl-1,2,3,6-tetrahydropiridine (MPTP)." Acta Neurobiol Exp (Wars) 63(2): 109-15.
 The pathological process of neurodegeneration is accompanied by an inflammatory reaction that is believed to contribute to the pathogenesis of neurodegenerative diseases. The aim of our study was to evaluate the influence of autoimmune reaction induced by post-traumatic vaccination with myelin self-antigen on spontaneous regeneration of dopaminergic neurons, injured with MPTP. C57BL mice were intoxicated with 40 mg/kg MPTP and seven days later immunized with MOG 35-55 peptide in CFA. On the 7th day following intoxication, the MPTP treated mice showed decrease of the dopamine level by 63% as compared to the control mice. However, starting from the 14th day following intoxication, a spectacular increase of dopamine content was observed. Immunization with MOG resulted in a statistically significant reduction of the increase in striatum as compared to non-immunized animals, and was lower by 23%, 17% and 15% on days 14, 28 and 50, respectively. Our results show suppressive influence of autoimmune reaction induced after injury on regeneration of dopamine cells intoxicated with MPTP.

Bambakidis, N. C., R. Z. Wang, et al. (2003). "Sonic hedgehog-induced neural precursor proliferation after adult rodent spinal cord injury." J Neurosurg 99(1 Suppl): 70-5.
 OBJECT: The glycoprotein molecule sonic hedgehog (Shh) has been shown to play a critical role in neuraxial development. To assess its role in the repair of demyelination following spinal cord injury (SCI), escalating doses of Shh were injected into demyelinated lesions in adult rat spinal cords. METHODS: Twenty-seven adult rats underwent thoracic laminectomy and chemical demyelination of the spinal cord dorsal columns without neurological deficit A subset of 20 rats was treated after 3 days by direct injection of Shh at two different doses. Rats were killed at 7 or 21 days after SCI, and tissue samples underwent immediate fixation or were placed into cell culture. Diffuse cellular proliferative responses throughout the gray and white matter were observed in up to 70% of Shh-treated rats. Proliferation around the central canal, believed to be derived from the ventricular ependyma consistent with neuronal stem cell induction, was demonstrated in up to 60% of the treated rats. No significant proliferation in these areas was detected in control rats. Dorsal areas of nestin-positive cells were also observed in 70% of rats treated with high doses of Shh, and these observations were reproduced in cell culture as well as in cultures of dorsal spinal cord explants. Cell counts revealed significant increases in the percentage of oligodendrocyte precursors and neurons in treated compared with control rats. CONCLUSIONS: Exogenous Shh administration promotes nestin-positive cell proliferation after SCI in adult rodents. These cells are believed to be derived from neural precursor cells. The populations of oligodendrocyte precursors and neurons were likewise increased in Shh-treated rats, suggesting that these cells may be derived from neural stem cells.

Bandtlow, C. E. (2003). "Regeneration in the central nervous system." Exp Gerontol 38(1-2): 79-86.
 Unlike neonatal axons, mammalian adult axons of the CNS do not regenerate after injury. This developmental loss of regenerative capacity, is correlated with the onset of myelination. Likewise, myelin, or myelin-associated components such as Nogo-A and myelin-associated glycoprotein (MAG) inhibit regeneration from older but not younger neurons. Identification of the molecular events responsible for this developmental loss of regenerative capacity is central to devise strategies to encourage regeneration in adults after injury. Endogenous levels of the cyclic nucleotides cAMP and cGMP have been suggested to determine the neuronal responsiveness to various axonal guidance factors. Elevating cAMP concentrations block Nogo-A or MAG induced inhibition of neurite outgrowth in older neurons, whereas suppressing cAMP levels in young neurons renders them susceptible to Nogo-A and MAG. Interestingly, elevated cAMP levels abrogated the Nogo-A and MAG mediated activation of RhoA and down regulation of Rac1 in adult neurons. In contrast, elevation of cAMP leads to the inactivation of RhoA and prevents activation of downstream effector proteins, while Rac is activated. We therefore conclude that the endogenous neuronal cAMP levels determine the neuronal responsiveness to myelin-associated neurite growth inhibitors by regulating rho GTPase activities.

Barcelos, A. S., A. C. Rodrigues, et al. (2003). "Inside-out vein graft and inside-out artery graft in rat sciatic nerve repair." Microsurgery 23(1): 66-71.
 Although veins and arteries present similar wall structures, there are differences which may be relevant in peripheral nerve reconstruction. Inside-out vein grafts (IOVG) have been satisfactorily used to repair both motor and sensitive nerves. However, the inside-out artery graft (IOAG) is a new technique and not fully investigated. Our study presents comparative morphological data on nerve regeneration achieved with IOVG and IOAG in the repair of Wistar rat sciatic nerves. Jugular veins and aorta arteries were harvested from donor animals and used "inside-out" to bridge a 10-mm gap. Animals were sacrificed at 10 weeks to evaluate nerve regeneration. Both techniques presented great variability in nervous tissue, though some animals showed satisfactory results. Different intensities of scarring processes might have interfered with nerve regeneration. Although IOVG and IOAG techniques showed similar morphometric results, in general, IOVG presented a closer-to-normal nerve organization than IOAG.

Bareyre, F. M. and M. E. Schwab (2003). "Inflammation, degeneration and regeneration in the injured spinal cord: insights from DNA microarrays." Trends Neurosci 26(10): 555-63.
 
Barres, B. A. (2003). "What is a glial cell?" Glia 43(1): 4-5.
 
Beazley, L. D., J. Rodger, et al. (2003). "Training on a visual task improves the outcome of optic nerve regeneration." J Neurotrauma 20(11): 1263-70.
 Optic nerve regeneration in a lizard, Ctenophorus ornatus, is dysfunctional despite survival of most retinal ganglion cells and axon regeneration to the optic tectum. The regenerated retino-tectal projection at 6 months has crude topography but by 1 year is disordered; visually-elicited behavior is absent via the experimental eye. Here, we assess the influence of training on the outcome of optic nerve regeneration. Lizards were trained to catch prey presented within the monocular field of either eye. One optic nerve was then severed and visual stimulation resumed throughout regeneration. In the trained group, presentation was restricted to the eye undergoing optic nerve regeneration; for the untrained group, the unoperated eye was stimulated. Pupil responses returned in trained but not in untrained animals. At 1 year, trained animals oriented to and captured prey; untrained animals demonstrated minimal orienting and failed to capture prey. Regenerated retino-tectal projections were topographic in the trained but not in the untrained group as assessed by in vitro electrophysiological recording and by carbocyanine dye tracing. In vitro electrophysiological recording during application of neurotransmitter antagonists to the tectum revealed that the level of GABAergic inhibition was modest in trained animals but elevated in the untrained group; responses were mainly AMPA-mediated in both groups. We conclude that training improves the behavioral outcome of regeneration, presumably by stabilizing and refining the transient retino-tectal map and preventing a build-up of tectal inhibition. The results suggest that for successful central nerve regeneration to occur in mammals, it may be necessary to introduce training to complement procedures stimulating axon regeneration.

Becker, D., C. L. Sadowsky, et al. (2003). "Restoring function after spinal cord injury." Neurolog 9(1): 1-15.
 BACKGROUND: By affecting young people during the most productive period of their lives, spinal cord injury is a devastating problem for modern society. A decade ago, treating SCI seemed frustrating and hopeless because of the tremendous morbidity and mortality, life-shattering impact, and limited therapeutic options associated with the condition. Today, however, an understanding of the underlying pathophysiological mechanisms, the development of neuroprotective interventions, and progress toward regenerative interventions are increasing hope for functional restoration. REVIEW SUMMARY: This study addresses the present understanding of SCI, including the etiology, pathophysiology, treatment, and scientific advances. The discussion of treatment options includes a critical review of high-dose methylprednisolone and GM-1 ganglioside therapy. The concept that limited rebuilding can provide a disproportionate improvement in quality of life is emphasized throughout. CONCLUSIONS: New surgical procedures, pharmacologic treatments, and functional neuromuscular stimulation methods have evolved over the last decades that can improve functional outcomes after spinal cord injury, but limiting secondary injury remains the primary goal. Tissue replacement strategies, including the use of embryonic stem cells, become an important tool and can restore function in animal models. Controlled clinical trials are now required to confirm these observations. The ultimate goal is to harness the body's own potential to replace lost central nervous system cells by activation of endogenous progenitor cell repair mechanisms.

Bedogni, B., G. Pani, et al. (2003). "Redox regulation of cAMP-responsive element-binding protein and induction of manganous superoxide dismutase in nerve growth factor-dependent cell survival." J Biol Chem 278(19): 16510-9.
 Reactive oxygen species (ROS) act as both signaling molecules and mediators of cell damage in the nervous system and are implicated in the pathogenesis of neurodegenerative diseases. Neurotrophic factors such as the nerve-derived growth factor (NGF) support neuronal survival during development and promote regeneration after neuronal injury through the activation of intracellular signals whose molecular effectors and downstream targets are still largely unknown. Here we present evidence that early oxidative signals initiated by NGF in PC12 cells, an NGF-responsive cell line, play a critical role in preventing apoptosis induced by serum deprivation. This redox-signaling cascade involves phosphatidylinositol 3-kinase, the small GTPase Rac-1, and the transcription factor cAMP-responsive element-binding protein (CREB), a molecule essential to promote NGF-dependent survival. We found that ROS are necessary for NGF-dependent phosphorylation of CREB, an event directly correlated with CREB activity, whereas hydrogen peroxide induces a robust CREB phosphorylation. Cells exposed to NGF show a late decrease in the intracellular content of ROS when compared with untreated cells and increased expression of the mitochondrial antioxidant enzyme manganese superoxide dismutase, a general inhibitor of cell death. Accordingly, serum deprivation-induced apoptosis was selectively inhibited by low concentrations of the mitochondrially targeted antioxidant Mito Q (mitoquinol/mitoquinone). Taken together, these data demonstrate that the oxidant-dependent activation of CREB is a component of NGF survival signaling in PC12 cells and outline an intriguing circuitry by which a cytosolic redox cascade promotes cell survival at least in part by increasing mitochondrial resistance to oxidative stress.

Befort, K., L. Karchewski, et al. (2003). "Selective up-regulation of the growth arrest DNA damage-inducible gene Gadd45 alpha in sensory and motor neurons after peripheral nerve injury." Eur J Neurosci 18(4): 911-22.
 The growth arrest and DNA damage-inducible gene 45 alpha (Gadd45a) was one of 240 genes found previously by high density oligonucleotide microarray analysis to be regulated in the rat L4 and L5 dorsal root ganglia 3 days after transection of the sciatic nerve (>four-fold up-regulation). The Gadd45a mRNA expression profile investigated by northern blot, RNase protection assay and in situ hybridization in the rat shows negligible constitutive mRNA levels in embryonic, neonatal or adult intact dorsal root ganglia. Within 24 h of a sciatic nerve injury, a very large induction is found that persists for as long as regeneration of injured fibres is prevented by peripheral nerve ligation. When axons are allowed to regrow following sciatic nerve crush injury, Gadd45a expression is terminated at later time points, when levels of other markers of injury return towards normal. Colocalization with activating transcription factor 3-LI and c-jun mRNA implies that all peripherally injured primary sensory and motor neurons express Gadd45a mRNA. Injury to the central axons of dorsal root ganglion neurons produces only a minimal induction of Gadd45a while peripheral inflammation is without effect. Gadd45a is a specific marker of the presence of peripheral axonal injury in adult primary sensory and motor neurons.

Belecky-Adams, T., M. Holmes, et al. (2003). "An intact intermediate filament network is required for collateral sprouting of small diameter nerve fibers." J Neurosci 23(28): 9312-9.
 Expression of the intermediate filament (IF) protein peripherin is initiated during development at the time of axonal extension and increases during regeneration of nerve fibers. To test whether the IF network is essential for neuron process outgrowth in the mature organism in vivo, we disrupted endogenous peripherin IF in small-sized dorsal root ganglion (DRG) neurons in transgenic mice via expression of a mutant peripherin transgene under control of peripherin gene regulatory sequences. Anatomical and functional analyses showed that these neurons send peripheral and central axonal projections to correct targets, express correct neuropeptides, and mediate acute pain responses normally. However, disruption of IF significantly impaired the ability of uninjured small-sized DRG neurons to sprout collateral axons into adjacent denervated skin, indicating a critical role for intact IF in plasticity, specifically in compensatory nociceptive nerve sprouting.

ben-Aaron, M. (2003). "Topological aspects of axonal regeneration." Med Hypotheses 61(5-6): 597-600.
 The fibers making up any sensory system in the spinal cord come from the same cells as do the fibers in peripheral nerves yet severed nerve fibers in the adult spinal cord do not regenerate but damaged peripheral nerves - those in the extremities - do heal themselves. Why should spinal cord regeneration even be an issue, why should an inhibiting protein have evolved to prevent it and what causes this protein to be expressed? From a holistic perspective, an answer to this conundrum shows that these questions are intertwined, and suggests that: (1) The model of the neurons as 'wires' is too simplistic. (2) In humans, the 'map' of individual connections is (topologically, at least) locally variable, though the overall global topology and 'functionality' of each normal spinal cord is constant. Both of these issues have to be addressed if functional restoration is to be achieved.

Benitez-Temino, B., R. R. de la Cruz, et al. (2003). "Grafting of a new target prevents synapse loss in abducens internuclear neurons induced by axotomy." Neuroscience 118(3): 611-26.
 The loss of afferent synaptic boutons is a prominent alteration induced by axotomy on adult central neurons. In this work we attempted to prove whether synapse loss could be reverted by reconnection with a new target. We severed the medial longitudinal fascicle of adult cats and then transplanted embryonic cerebellar primordia at the lesion site immediately after lesion. As previously shown, the transected axons from abducens internuclear neurons penetrate and reinnervate the graft [J Comp Neurol 444 (2002) 324]. By immunocytochemistry and electron microscopy we studied the synaptology of abducens internuclear neurons under three conditions: control, axotomy and transplant (2 months of survival time). Semithin sections of the abducens nucleus were immunostained against calretinin, to identify abducens internuclear neurons, and either synaptophysin (SF), to label synaptic terminals, or glial fibrillary acidic protein (GFAP) to detect the astrocytic reaction. Optical and linear density of SF and GFAP immunostaining were measured. Data revealed a significant decrease in the density of SF-labeled terminals with a parallel increase in GFAP-immunoreactive elements after axotomy. On the contrary, in the transplant group, the density of SF-labeled terminals was found similar to control, and the astrocytic reaction induced by lesion was significantly reduced. At the ultrastructural level, synaptic coverage and linear density of boutons were measured around the somata of abducens internuclear neurons. Whereas a significant reduction in both parameters was found after axotomy, cells of the transplant group received a normal density of synaptic endings. The ratio between F- and S-type boutons was found similar in the three groups. Therefore, these findings indicate that the grafting of a new target can prevent the loss of afferent synaptic boutons produced by the axotomy.

Benjamin, B. (2003). "Vocal cord paralysis, synkinesis and vocal fold motion impairment." ANZ J Surg 73(10): 784-6.
 Felix Semon's 'laws' of vocal cord paralysis were conceived over a century ago, based on the simple concept that abductor function of the recurrent laryngeal nerve was more vulnerable than adductor function. It is now clear that the neuromuscular pathology of laryngeal innervation is much more complex. Whether the nerve has been cut, crushed, stretched, cauterized or otherwise injured, it is seldom completely transected. There might be no detectable vocal cord movement at laryngoscopy, yet, electromyography usually shows at least some activity because of incomplete denervation and/or developing synkinesis. Electrical silence hardly ever persists forever. Disordered vocal fold movement following nerve injury appears to depend on laryngeal synkinesis with disorganized neuromuscular function caused by misdirected regeneration and aberrant reinnervation, sometimes by adjacent nerves. The severity of the injury, abnormal random reinnervation, scar tissue formation and nerve growth-stimulating and inhibiting factors influence the final position of the vocal fold. For a better understanding of neurolaryngological disorders it is no longer sufficient to think merely in terms of 'vocal cord paralysis'.

Bermingham-McDonogh, O. and E. W. Rubel (2003). "Hair cell regeneration: winging our way towards a sound future." Curr Opin Neurobiol 13(1): 119-26.
 The discovery of hair cell regeneration in the inner ear of birds provides new optimism that there may be a treatment for hearing and balance disorders. In this review we describe the process of hair cell regeneration in birds; including restoration of function, recovery of perception and what is currently known about molecular events, such as growth factors and signalling systems. We examine some of the key recent findings in both birds and mammals.

Bertelli, J. A. and M. F. Ghizoni (2003). "Nerve repair by end-to-side coaptation or fascicular transfer: a clinical study." J Reconstr Microsurg 19(5): 313-8.
 End-to-side nerve repair has recently achieved special interest in the laboratory. In clinical practice, its use remains controversial and very few studies have been published. In the present report, nerve repair by end-to-side neurorrhaphy and by fascicular transfer is evaluated in seven patients. Clinical, electrophysiologic and histologic recovery was not observed in the patients who underwent end-to-side nerve coaptation, but recovery was observed when a fascicular transfer was performed.

Bertelli, J. A. and M. F. Ghizoni (2003). "Brachial plexus avulsion injury repairs with nerve transfers and nerve grafts directly implanted into the spinal cord yield partial recovery of shoulder and elbow movements." Neurosurgery 52(6): 1385-9; discussion 1389-90.
 OBJECTIVE: Complete avulsion of the brachial plexus is a devastating injury that primarily affects young adults. The current treatment is based on nerve transfers, which yield very limited recovery. In this study, brachial plexus injuries were repaired with nerve transfers and nerve grafts directly implanted into the spinal cord. METHODS: Eight patients with complete brachial plexus avulsion injuries were surgically treated. Roots or target nerves of the brachial plexus were repaired with peripheral nerve grafts directly implanted into the spinal cord and with extraplexal nerve transfers. RESULTS: Muscle reinnervation was observed for six patients who received spinal implants. Among those patients, one recovered M4 muscle power. Reinnervation was observed only in proximal upper limb muscles. CONCLUSION: Muscle reinnervation through nerve grafts directly implanted into the spinal cord was demonstrated. It seems that the combination of intra- and extradural neurotizations improves the proximal muscle function results. However, the extent of this improvement is limited and, in our opinion, does not justify the use of spinal implants.

Biers, S. M. and A. F. Brading (2003). "Nerve regeneration: might this be the only solution for functional problems of the urinary tract?" Curr Opin Urol 13(6): 495-500.
 SUMMARY: PURPOSE OF REVIEW To assess the potential role of nerve regeneration in restoring urinary tract function, the rapidly developing and exciting area of central and peripheral nerve repair and regeneration is reviewed, with particular reference to papers in which animal models of nerve damage resulting in urogenital dysfunction have been used. The difficulties and potential of these techniques for therapeutic application to human subjects with functional problems of the urinary tract are discussed.RECENT FINDINGS Methods for encouraging regeneration of cut axons and directed growth in the inhibitory environment of the central nervous system are being extensively explored. The recent discovery of the potential of olfactory ensheathing cells has proved a significant advance. Olfactory ensheathing cells are a type of glial cell which can be harvested from the olfactory mucosa. Transplantation of these cells, in conjunction with a biodegradable synthetic nerve guide or conduit, has been shown to restore urinary tract function after spinal cord injury. Artificial, biodegradable conduits have also restored bladder and spermatic duct function after sympathetic nerve damage. Other adjuvants facilitating the process of axonal recovery include the use of neurotrophins to accelerate and guide the formation of new nerve-fibre growth.SUMMARY These revolutionary technologies may, in the future, provide a means of treating urinary tract dysfunction with some types of aetiology, including acute spinal cord injury, and injury to nerves following pelvic surgery. It is, however, less likely that these treatments will be used successfully in the near future in patients in which the neural damage is long term, or associated with death of post-ganglionic neurons.

Biran, R., M. D. Noble, et al. (2003). "Directed nerve outgrowth is enhanced by engineered glial substrates." Exp Neurol 184(1): 141-52.
 In the present study, the influence of astrocyte alignment on the direction and length of regenerating neurites was examined in vitro. Astrocytes were experimentally manipulated by different approaches to create longitudinally aligned monolayers. When cultured on the aligned monolayers, dorsal root ganglion neurites grew parallel to the long axis of the aligned astrocytes and were significantly longer than controls. Engineered monolayers expressed linear arrays of fibronectin, laminin, neural cell adhesion molecule, and chondroitin sulfate proteoglycan that were organized parallel to one another, suggesting that a particular spatial arrangement of these molecules on the astrocyte surface may be necessary to direct nerve regeneration in vivo. In contrast, no bias in directional outgrowth was observed for neurites growing on unorganized monolayers. The results suggest that altering the organization of astrocytes and their scar-associated matrix at the lesion site may be used to influence the direction and the length of adjacent regenerating axons in the damaged brain and spinal cord.

Bird, E. V., F. M. Boissonade, et al. (2003). "Neuropeptide expression following ligation of the ferret lingual nerve." Arch Oral Biol 48(7): 541-6.
 Previous studies on the ferret inferior alveolar nerve found a close association between the spontaneous neural activity generated at a site of nerve injury, and the accumulation of neuropeptides in the injured axons. More recent electrophysiological studies on the lingual nerve revealed high levels of spontaneous activity 3 days after injury, a decline at 3 weeks and a late rise at 3 months. In the present study we have used immunocytochemical techniques to see whether this time course of spontaneous activity is again paralleled by an accumulation of neuropeptides. In 20 anaesthetised adult ferrets the left lingual nerve was ligated and sectioned distally, and the animals left to recover for 3 days, 3 weeks or 3 months. The tissue was processed using indirect immunofluorescence and image analysis was used to quantify levels of the neuropeptides; calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP), galanin (GAL), enkephalin (ENK) and neuropeptide Y (NPY). Immunoreactivity to all of the neuropeptides was present proximal to the ligature 3 days after injury, and these high levels of expression had decreased considerably by 3 weeks. By 3 months ENK and NPY expression had almost disappeared proximal to the ligature, but levels of CGRP, SP, VIP and GAL had increased slightly. This was also accompanied by an accumulation of all of the neuropeptides, except NPY, in the portion of nerve immediately distal to the ligature. This late accumulation of certain neuropeptides coincides with the increase in spontaneous activity seen in our previous electrophysiological studies and supports the suggestion that neuropeptides may play a role in the aetiology of sensory disorders after nerve injury.

Birouk, N., H. Azzedine, et al. (2003). "Phenotypical features of a Moroccan family with autosomal recessive Charcot-Marie-Tooth disease associated with the S194X mutation in the GDAP1 gene." Arch Neurol 60(4): 598-604.
 BACKGROUND: The first locus for demyelinating autosomal recessive Charcot-Marie-Tooth (ARCMT) disease was identified in 8q13, where mutations in GDAP1 have been found. Mutations in the same gene have been detected in families with axonal ARCMT disease. OBJECTIVE: To determine the clinical, electrophysiologic, and morphologic characteristics of a consanguineous Moroccan family with ARCMT disease associated with the S194X mutation in the GDAP1 gene. METHODS: Four patients from a consanguineous Moroccan family were examined clinically and electrophysiologically. In one patient, a morphometric and ultrastructural study of a peroneal nerve biopsy sample was performed. Mutation in the coding region of the GDAP1 gene was identified by direct sequencing. RESULTS: Neuropathy was evident early in childhood, walking was delayed in one patient, and onset of symptoms occurred before 18 months in the others. The phenotype was severe: foot deformities and disabilities involving the hands and feet developed toward the end of the first decade, followed by involvement of proximal muscles in the lower limbs, leading to loss of autonomy. Electrophysiologic findings were consistent with an axonal form of CMT disease: motor nerve conduction velocities, recordable in one patient only, were greater than 40 m/sec. Sensory nerve action potentials were either abolished or substantially reduced in amplitude. The morphologic data supported the diagnosis of axonal neuropathy, showing a marked reduction in myelinated fibers and signs of axonal regeneration, including frequent pseudo-onion bulb formations. The 4 patients in this family were homozygous for the S194X mutation in the GDAP1 gene. CONCLUSION: Electrophysiologic and pathological findings support the hypothesis of an axonal disorder in this ARCMT family with the S194X mutation in the GDAP1 gene.

Blaauw, G. and A. C. Slooff (2003). "Transfer of pectoral nerves to the musculocutaneous nerve in obstetric upper brachial plexus palsy." Neurosurgery 53(2): 338-41; discussion 341-2.
 OBJECTIVE: To investigate the results of transfer of pectoral nerves to the musculocutaneous nerve for treatment of obstetric brachial palsy. METHODS: In 25 cases of obstetric brachial palsy (20 after breech deliveries), branches of the pectoral nerve plexus were transferred directly to the musculocutaneous nerve. For all patients, the nerve transfer was part of an extended brachial plexus reconstruction. Results were tested both clinically and with the Mallet scale, at a mean follow-up time of 70 months (standard deviation, 34.3 mo). RESULTS: There were two complete failures, which were attributable to disconnection of the transferred nerve endings. The results after transfer were excellent in 17 cases and fair in 5 cases. Steindler flexorplasty improved elbow flexion for three patients. CONCLUSION: Transfer of pectoral nerves to the musculocutaneous nerve for treatment of obstetric upper brachial palsy may be effective, if the specific anatomic features of the pectoral nerve plexus are sufficiently appreciated.

Blits, B., M. Oudega, et al. (2003). "Adeno-associated viral vector-mediated neurotrophin gene transfer in the injured adult rat spinal cord improves hind-limb function." Neuroscience 118(1): 271-81.
 To foster axonal growth from a Schwann cell bridge into the caudal spinal cord, spinal cells caudal to the implant were transduced with adeno-associated viral (AAV) vectors encoding for brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (AAV-NT-3). Control rats received AAV vectors encoding for green fluorescent protein or saline. AAV-BDNF- and AAV-NT-3-transduced 293 human kidney cells produced and secreted BDNF or NT-3, respectively, in vitro. The secreted neurotrophins were biologically active; they both promoted outgrowth of sensory neurites in vitro. In vivo, transgene expression was observed predominantly in neurons for at least 16 weeks after injection. Compared with controls, a modest though significant improvement in hind-limb function was found in rats that received AAV-BDNF and AAV-NT-3. Retrograde tracing demonstrated that twice as many neurons with processes extending toward the Schwann cell graft were present in the second lumbar cord segment of AAV-BDNF- and AAV-NT-3-injected animals compared with controls. We found no evidence, however, for growth of regenerated axons from the Schwann cell implant into the caudal cord.Our results suggest that AAV vector-mediated overexpression of BDNF and NT-3 in the cord caudal to a Schwann cell bridge modified the local lumbar axonal circuitry, which was beneficial for locomotor function.

Bontioti, E. N., M. Kanje, et al. (2003). "Regeneration and functional recovery in the upper extremity of rats after various types of nerve injuries." J Peripher Nerv Syst 8(3): 159-68.
 The aim was to establish an accurate, reproducible, and simple method to evaluate functional recovery after different types of nerve injuries to the brachial plexus of rats. To that end, pawprints, measured as distance between the first and fourth and second and third digits, were used for evaluation of injuries including crush injury, transection/repair, or graft repair of the median, ulnar, and radial nerves. Immunocytochemistry of the C-terminal flanking peptide of neuropeptide Y (CPON) and neurofilaments was used to investigate the cell body response and axonal outgrowth, respectively. Functional recovery was dependent on the severity as well as on the level of the lesion. Neither a single injury to the median nerve nor an injury to the ulnar nerve affected the pawprint, while an injury to both these nerves or a single injury to the radial nerve caused impairment of pawprints. There was a rapid recovery after crush injury to these nerves compared to previous reports of a similar injury to the sciatic nerve. The pattern of axonal outgrowth was related to the severity of the lesion. A conditioning lesion, i.e., an initial lesion of the same nerve preceding a test injury by a few days, of both motor/sensory fibers led to a quicker functional recovery. Surprisingly, conditioning of only sensory fibers had nearly the same effect. The cell body response was dependent on the level of the nerve lesion. The upper extremity of rats might be useful to evaluate the effects of new repair methods after nerve injuries using functional evaluation with pawprints as a simple and accurate method.

Borgens, R. B. (2003). "Restoring function to the injured human spinal cord." Adv Anat Embryol Cell Biol 171: III-IV, 1-155.
 Of catastrophic traumas to the human body, spinal cord injury (SCI) has least benefited innovations arising from the new biology. Since after WW II, the "standard of care" for SCI has changed little. The controversial use of high dosages of steroids has provided only modest benefit to patients--but not without the enhanced risk of mortality. Novel therapies arising from biochemistry and genetics have not materialized in over 15 years, and are unlikely to in the author's opinion. Instead, appreciation of biophysics and cell physiology in controlling nerve injury, growth, regeneration, and function has produced innovative clinical approaches now in testing in human spinal cord injury.

Borisoff, J. F., C. C. Chan, et al. (2003). "Suppression of Rho-kinase activity promotes axonal growth on inhibitory CNS substrates." Mol Cell Neurosci 22(3): 405-16.
 Several molecules inhibit axonal growth cones and may account for the failure of central nervous system regeneration, including myelin proteins and various chondroitan sulfate proteoglycans expressed at the site of injury. Axonal growth inhibition by myelin and chondroitan sulfate proteoglycans may in part be controlled by Rho-GTPase, which mediates growth cone collapse. Here, we tested in vitro whether pharmacological inhibition of a major downstream effector of Rho, Rho-kinase, promotes axonal outgrowth from dorsal root ganglia grown on aggrecan. Aggrecan substrates stimulated Rho activity and were inhibitory to axonal growth. Y-27632 treatment promoted the growth of axons by 5- to 10-fold and induced "steamlined" growth cones with longer filopodia and smaller lamellipodia. Interestingly, more actin bundles reminiscent of stress fibers in the central domain of the growth cone were observed when grown on aggrecan compared to laminin. In addition, Y-27632 significantly promoted axonal growth on both myelin and adult rat spinal cord cryosections. Our data suggest that suppression of Rho-kinase activity may enhance axonal regeneration in the central nervous system.

Borschel, G. H., K. F. Kia, et al. (2003). "Mechanical properties of acellular peripheral nerve." J Surg Res 114(2): 133-9.
 BACKGROUND: Acellular nerve has been used in experimental models as a peripheral nerve substitute. Our objective was to determine the difference in tensile strength between fresh and chemically treated acellularized peripheral nerve. MATERIALS AND METHODS: F344 rat sciatic nerves were either fresh or acellularized and tested either whole (Part A) or transected and repaired (Part B). For all constructs, the mean ultimate stress, mean ultimate strain, Young's modulus, and total mechanical work to fracture were calculated.The average ultimate strains for Groups A-1 and A-2 were 0.480 +/- 0.117 and 0.810 +/- 0.114, respectively. The Young's moduli in Groups A-1 and A-2 were 576 +/- 160 and 580 +/- 150 kPa, respectively. In Groups A-1 and A-2, the normalized work to failure was 0.35 +/- 0.14 and 1.11 +/- 0.38 N. The specimens in Group B-1 withstood an average ultimate stress of 780 +/- 280 kPa. The specimens in Group B-2 withstood an average ultimate stress of 405 +/- 20 kPa. RESULTS: The average ultimate strains for Groups B-1 and B-2 were 0.319 +/- 0.087 and 0.266 +/- 0.019, respectively. The Young's moduli in Groups B-1 and B-2 were 4,030 +/- 1360 and 2,290 +/- 280 kPa, respectively. The normalized work to failure in Groups B-1 and B-2 was calculated as 0.22 +/- 0.04 and 0.11 +/- 0.02 N. CONCLUSIONS: Although adequately robust for reconstructive procedures, the acellular peripheral nerve had decreased tensile strength compared with fresh nerve either when tested whole or when transected and repaired.

Bouslama-Oueghlani, L., R. Wehrle, et al. (2003). "The developmental loss of the ability of Purkinje cells to regenerate their axons occurs in the absence of myelin: an in vitro model to prevent myelination." J Neurosci 23(23): 8318-29.
 Axonal regeneration in the mammalian CNS is a property of immature neurons that is lost during development. Using organotypic culture of cerebellum, we have shown that in vitro Purkinje cells lose their regenerative capacity in parallel with the process of myelination. We have investigated whether myelination is involved in the age-dependent loss of regeneration of these neurons. By applying a high dose of bromodeoxyuridine in the culture medium of newborn cerebellar slices during the first 3 d in vitro, we have succeeded in obtaining cultures with oligodendrocyte depletion, together with a lack of ameboid microglia and enhancement of Purkinje cell survival. These cultures, after 14 d in vitro, are completely devoid of myelin. We have compared the ability of Purkinje cells to regenerate their axons in the presence or absence of myelin. Purkinje cells in cerebellar explants taken at birth, treated with bromodeoxyuridine and axotomized after 7 d in vitro, survive better than similar neurons in untreated cultures. However, despite the lack of myelin and the enhanced survival, Purkinje cells do not regenerate, whereas they do regenerate when the axotomy is done at postnatal day 0. Thus, the Purkinje cell developmental switch from axonal regeneration to lack of regeneration does not appear to be regulated by myelin.

Boyd, J. G. and T. Gordon (2003). "Glial cell line-derived neurotrophic factor and brain-derived neurotrophic factor sustain the axonal regeneration of chronically axotomized motoneurons in vivo." Exp Neurol 183(2): 610-9.
 In contrast to injuries in the central nervous system, injured peripheral neurons will regenerate their axons. However, axotomized motoneurons progressively lose their ability to regenerate their axons, following peripheral nerve injury often resulting in very poor recovery of motor function. A decline in neurotrophic support may be partially responsible for this effect. The initial upregulation of glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) by Schwann cells of the distal nerve stump after nerve injury has led to the speculation that they are important for motor axonal regeneration. However, few experiments directly measure the effects of exogenous BDNF or GDNF on motor axonal regeneration. This study provided the first direct and quantitative evidence that long-term continuous treatment with exogenous GDNF significantly increased the number of motoneurons which regenerate their axons, completely reversing the negative effects of chronic axotomy. The beneficial effect of GDNF was not dose-dependent. A combination of exogenous GDNF and BDNF on motor axonal regeneration was significantly greater than either factor alone, and this effect was most pronounced following long-term continuous treatment. The ability of GDNF, either alone or in combination with BDNF, to increase the number of motoneurons that regenerated their axons correlated well with an increase in axon sprouting within the distal nerve stump. Thus long-term continuous treatment with neurotrophic factors, such as GDNF and BDNF, can be used as a viable treatment to sustain motor axon regeneration.

Boyd, J. G., V. Skihar, et al. (2003). "Olfactory ensheathing cells: historical perspective and therapeutic potential." Anat Rec 271B(1): 49-60.
 Olfactory ensheathing cells (OECs) are the glial cells that ensheath the axons of the first cranial nerve. They are attracting increasing attention from neuroscientists as potential therapeutic agents for use in the repair of spinal cord injury and as a source of myelinating glia for use in remyelinating axons in demyelinating diseases such as multiple sclerosis. This review mainly addresses the cell biological aspects of OECs pertinent to addressing two questions. Namely, where do OECs fit into the groupings of central nervous system (CNS)/peripheral nervous system (PNS) glial cells and should OECs be viewed as a clinically relevant alternative to Schwann cells in the treatment of spinal cord injury? The evidence indicates that OECs are indeed a clinically relevant alternative to Schwann cells. However, much more work needs to be done before we can even come close to answering the first question as to the lineage and functional relationship of OECs to the other types of CNS and PNS glial cells.

Boyd, J. G. and T. Gordon (2003). "Neurotrophic factors and their receptors in axonal regeneration and functional recovery after peripheral nerve injury." Mol Neurobiol 27(3): 277-324.
 Over a half a century of research has confirmed that neurotrophic factors promote the survival and process outgrowth of isolated neurons in vitro. The mechanisms by which neurotrophic factors mediate these survival-promoting effects have also been well characterized. In vivo, peripheral neurons are critically dependent on limited amounts of neurotrophic factors during development. After peripheral nerve injury, the adult mammalian peripheral nervous system responds by making neurotrophic factors once again available, either by autocrine or paracrine sources. Three families of neurotrophic factors were compared, the neurotrophins, the GDNF family of neurotrophic factors, and the neuropoetic cytokines. Following a general overview of the mechanisms by which these neurotrophic factors mediate their effects, we reviewed the temporal pattern of expression of the neurotrophic factors and their receptors by axotomized motoneurons as well as in the distal nerve stump after peripheral nerve injury. We discussed recent experiments from our lab and others which have examined the role of neurotrophic factors in peripheral nerve injury. Although our understanding of the mechanisms by which neurotrophic factors mediate their effects in vivo are poorly understood, evidence is beginning to emerge that similar phenomena observed in vitro also apply to nerve regeneration in vivo.

Brauer, A. U., N. E. Savaskan, et al. (2003). "A new phospholipid phosphatase, PRG-1, is involved in axon growth and regenerative sprouting." Nat Neurosci 6(6): 572-8.
 Outgrowth of axons in the central nervous system is governed by specific molecular cues. Molecules detected so far act as ligands that bind to specific receptors. Here, we report a new membrane-associated lipid phosphate phosphatase that we have named plasticity-related gene 1 (PRG-1), which facilitates axonal outgrowth during development and regenerative sprouting. PRG-1 is specifically expressed in neurons and is located in the membranes of outgrowing axons. There, it acts as an ecto-enzyme and attenuates phospholipid-induced axon collapse in neurons and facilitates outgrowth in the hippocampus. Thus, we propose a novel mechanism by which axons are able to control phospholipid-mediated signaling and overcome the growth-inhibiting, phospholipid-rich environment of the extracellular space.

Brisby, H. (2003). "Nerve root injuries in patients with chronic low back pain." Orthop Clin North Am 34(2): 221-30.
 In conclusion, the nerve roots and the DRG play an important role in the pain mechanisms of patients suffering from chronic low back pain. Signs of demyelination and increased sensitization for stimuli occurs after a direct nerve root trauma, and the plasticity for the DRG also may change the response to a given peripheral stimuli when repeated frequently over a long period of time. The regeneration mechanisms of spinal nerve roots and DRG regarding function are slow, and the final grade of recurrence depends on the degree of injury. The limited regeneration mechanisms for nerve injury and the fact that "established chronic pain centers" are hard to influence after a long pain history favor an aggressive strategy for pain management. Today, a number of treatment strategies exist for chronic low back pain patients (with or without a diagnosed nerve root injury). These strategies include physiotherapy, nonsteroid anti-inflammatory drugs (NSAIDs), steroids, analgesics of different types and administration routes, surgery, and other sorts of invasive treatments. Further knowledge about the nerve root, DRG, and the rest of the nervous system in these patients is necessary; for understanding how and when to treat patients with chronic low back pain, we need to understand more about what we are trying to treat.

Bryant, S. M., K. L. Cumpston, et al. (2003). "Facial nerve neuritis secondary to ultraviolet radiation." Vet Hum Toxicol 45(4): 217-8.
 We describe a patient who developed facial nerve injury following significant exposure to UV radiation. A 49-y-old construction worker developed erythema and edema on the left side of his face (exposed side) 12 h after working within 18 in of a compromised metal halide incandescent light bulb for a total of 2 h. One month later, the patient noted a painful burning sensation over the left side of his face associated with marked left facial weakness and inability to close his eye (peripheral VIIth nerve palsy). Two months later, synkinetic left facial movements were consistent with aberrant regeneration. Over the next several months, forceful episodic spasmodic activity developed in the muscles of facial expression on the left, identical to that seen in hemifacial spasm. Rarely has UV radiation been implicated in damage to subcutaneous nerves. This case demonstrates that significant neurologic morbidity may follow high exposure to UV radiation.

Bryan, D. J., J. B. Tang, et al. (2003). "Enhanced peripheral nerve regeneration elicited by cell-mediated events delivered via a bioresorbable PLGA guide." J Reconstr Microsurg 19(2): 125-34.
 Using an established rat peripheral-nerve regeneration model, the authors have demonstrated enhancement of regeneration following subcutaneous priming of bioresorbable poly(lactic-co-glycolic)acid (PLGA) guides in vivo. Four weeks after nerve reconstruction, regeneration of the peripheral nerve through the cell-infiltrated guides displayed a significant increase in the total axon number and myelination status recorded in primed over unprimed guides, demonstrating the importance of cell-mediated events in the regeneration process. To define the different components enhancing nerve regeneration in this model, they have focused on identifying factors capable of eliciting Schwann-cell migration, since this has been identified as an early and necessary event in nerve regeneration. Using an in vitro migration assay, screening of a limited number of cellular and extracellular factors has demonstrated differential promotion of Schwann-cell migration. Of interest, combining fibronectin and bFGF resulted in a two-fold enhancement in Schwann-cell migration over that recorded with either alone. These results describe a rapid screening process for identifying various molecules and combinations thereof, with potential involvement in Schwann-cell migration. Coupling these findings to the use of the PLGA guide as an in vivo delivery system provides a rationale for the selection of exogenous factors to test for the enhancement of peripheral-nerve regeneration.

Buhusi, M., B. R. Midkiff, et al. (2003). "Close homolog of L1 is an enhancer of integrin-mediated cell migration." J Biol Chem 278(27): 25024-31.
 Close homolog of L1 (CHL1) is a member of the L1 family of cell adhesion molecules expressed by subpopulations of neurons and glia in the central and peripheral nervous system. It promotes neurite outgrowth and neuronal survival in vitro. This study describes a novel function for CHL1 in potentiating integrin-dependent cell migration toward extracellular matrix proteins. Expression of CHL1 in HEK293 cells stimulated their haptotactic migration toward collagen I, fibronectin, laminin, and vitronectin substrates in Transwell assays. CHL1-potentiated cell migration to collagen I was dependent on alpha1beta1 and alpha2beta1 integrins, as shown with function blocking antibodies. Potentiated migration relied on the early integrin signaling intermediates c-Src, phosphatidylinositol 3-kinase, and mitogen-activated protein kinase. Enhancement of migration was disrupted by mutation of a potential integrin interaction motif Asp-Gly-Glu-Ala (DGEA) in the sixth immunoglobulin domain of CHL1, suggesting that CHL1 functionally interacts with beta1 integrins through this domain. CHL1 was shown to associate with beta1 integrins on the cell surface by antibody-induced co-capping. Through a cytoplasmic domain sequence containing a conserved tyrosine residue (Phe-Ile-Gly-Ala-Tyr), CHL1 recruited the actin cytoskeletal adapter protein ankyrin to the plasma membrane, and this sequence was necessary for promoting integrin-dependent migration to extracellular matrix proteins. These results support a role for CHL1 in integrin-dependent cell migration that may be physiologically important in regulating cell migration in nerve regeneration and cortical development.

Burnett, A. L. (2003). "Neuroprotection and nerve grafts in the treatment of neurogenic erectile dysfunction." J Urol 170(2 Pt 2): S31-4; discussion S34.
 PURPOSE: The rationale for protecting the nerve supply of the penis derives mainly from the fact that neurological injury or disease states involving this organ commonly result in erectile dysfunction. Novel directions in the management of neurogenic erectile dysfunction that pertain specifically to sustaining penile neuronal function are described. MATERIALS AND METHODS: The review constitutes a summary of neuroprotective strategies for penile erection that are under investigation at the basic science level or have been brought to clinical practice. The basic exercise consisted primarily of a literature search using the National Library of Medicine PubMed Services, with references made to such keywords as nerve grafts, nerve growth factors, neuroprotection and nerve regeneration. RESULTS: Primary advances in this field have centered on repairing structural defects and restoring the functional integrity of the cavernous nerves of the penis. In the former autologous nerve conduits, such as sural nerve grafts, have been explored and used prominently in the context of radical prostatectomy. In the latter diverse neurotrophic treatments have been investigated, with progress mostly limited to animal models of cavernous nerve injury. Basic concepts and ongoing developments in the neurobiology of axonal regeneration were identified as being applicable to this area of neurourology. CONCLUSIONS: Because neurogenic origins represent a leading categorical cause of erectile dysfunction, the importance of developing and applying treatment approaches to alleviate neuropathic effects on the erectile tissue of the penis is certain. Medical and surgical innovations for preserving and reconstituting the functional nerve supply of the penis offer great promise in the management of erectile dysfunction.

Burnett, A. L. (2003). "Strategies to promote recovery of cavernous nerve function after radical prostatectomy." World J Urol 20(6): 337-42.
 While the application of penile autonomic nerve-sparing techniques during radical prostatectomy for clinically localized prostate cancer has improved erection recovery rates after surgery, many men still experience delayed or incomplete recovery of erectile function. In recognition of neuropathy as a likely basis for erectile dysfunction after radical prostatectomy, investigators have begun exploring new strategies to promote the functional recovery of nerves responsible for penile erection in the course of this management. Primary efforts continue for preserving the integrity of the penile nerves, while the next frontier in clinical management has encompassed strategies directed toward maximally restoring their function. Such strategies include cavernous nerve interposition grafting and neurotrophic treatments that meet nerve reconstructive and nerve regenerative objectives, respectively. Early successes with both innovations preclinically and clinically suggest their feasibility and potential roles to reduce the incidence of erectile dysfunction after radical prostatectomy. The purpose of this report is to review strategies under development to promote post-prostatectomy erectile function, particularly with respect to preserving penile innervation involved in this function.

Burnett, A. L. (2003). "Rationale for cavernous nerve restorative therapy to preserve erectile function after radical prostatectomy." Urology 61(3): 491-7.
 
Burrell, B. D., C. L. Sahley, et al. (2003). "Progressive recovery of learning during regeneration of a single synapse in the medicinal leech." J Comp Neurol 457(1): 67-74.
 The leech escape reflex-shortening of the body-can change with nonassociative conditioning, including sensitization, habituation, and dishabituation. Capacity for sensitization, which is an enhancement of the reflex, is lost when a single S-interneuron is ablated, but the reflex response itself remains. In the present experiments, the S-interneuron's axon in the living leech was filled with 6-carboxyfluorescein (6-CF) dye and cut with an argon laser microbeam (lambda = 488 nm). In contrast to sham-operated animals, axotomized preparations did not sensitize, reflecting the key role of the S-cell. By 2 weeks or more, S-cell axons had regenerated and reestablished synapses at their usual locations with neighboring S-cells. By 4 weeks, this restored the ability to sensitize to a level indistinguishable from that of controls, but an intermediate state of recovery was seen from 2-3 weeks after injury-a period not previously examined. The small capacity for sensitization among newly regenerated preparations was significantly lower than in sham controls but appeared higher than in animals whose cut S-cell axon had not regenerated its synapse. The results confirm the crucial role of the S-cell in sensitization. Moreover, full sensitization does not occur immediately upon synapse regeneration.

Buss, A., G. A. Brook, et al. (2003). "Gradual loss of myelin and formation of an astrocytic scar during Wallerian degeneration in the human spinal cord." Brain.
 Axons undergo Wallerian degeneration distal to a point of injury. Experimental investigations have documented many of the cellular and molecular events that underlie this behaviour. Since relatively little is known about such events in human CNS pathologies and current experimental intervention strategies indicate the possibility of significant axon regeneration along the original degenerated fibre tract, we performed an immunohistochemical investigation of the dynamics of Wallerian degeneration in post mortem spinal cords of patients who died 2 days to 30 years after either cerebral infarction or traumatic spinal cord injury. Neurofilament (NF) staining demonstrated a spatio-temporal pattern of axonal loss within degenerating descending nerve fibre tracts that could be detected close to the lesion as early as 12 days after injury and progressed to an almost complete loss of NF immunoreactivity at survival times of 1 year and longer. Immunohistochemistry for glial fibrillary acidic protein revealed a late astrocytic reaction starting at 4 months after injury in the degenerating tracts, leading to the long-term deposition of a dense astrocytic scar. These events were accompanied by the gradual reduction of myelin basic protein in affected nerve fibre tracts, leading to almost complete loss by 3 years after injury. Since the extracellular matrix molecule chondroitin sulphate proteoglycan (CSPG) is known to be strongly inhibitory for axonal regeneration and to be a major component of gliotic scar tissues, we investigated the possible deposition of CSPG within the degenerating nerve fibre tracts. Apart from a local up-regulation close to the lesion site, our results show no enhanced CSPG expression within degenerated tracts at any survival time. This suggests that despite the apparent lack of CSPG in Wallerian degeneration, the slow reduction of CNS myelin and the long-term deposition of a dense astrocytic scar may present an environment that is non-supportive for axon regrowth.

Buss, A. and M. E. Schwab (2003). "Sequential loss of myelin proteins during Wallerian degeneration in the rat spinal cord." Glia 42(4): 424-32.
 Axotomy of nerve fibers leads to the subsequent degeneration of their distal part, a process termed Wallerian degeneration (WD). While WD in the peripheral nervous system is usually followed by regeneration of the lesioned axons, central nervous system (CNS) neurons are generally unable to regrow. In this study, we investigated the process of WD in the dorsal columns of the rat spinal cord rostral to a mid-thoracic lesion. We confirm earlier studies describing a very delayed microglial and an early and sustained astroglial reaction finally leading to scar formation. Interestingly, we found a differential time course in the loss of myelin proteins depending on their location. Proteins situated on the periaxonal myelin membrane such as myelin associated glycoprotein disappeared early, within a few days after lesion, concomitantly with cytoskeletal axonal proteins, whereas compact myelin and outer myelin membrane proteins such as MBP and Nogo-A remained for long intervals in the degenerating tracts. Two distinct mechanisms are probably responsible for this difference: processes of protein destruction emanating from and initially probably located in the axon act on a time scale of 1-3 days. In contrast, the bulk of myelin destruction is due to phagocytosis known to be slow, prolonged, and inefficient in the CNS. These results may also have implications for future intervention strategies aiming at enhancing CNS regeneration.

Byers, M. R., H. Suzuki, et al. (2003). "Dental neuroplasticity, neuro-pulpal interactions, and nerve regeneration." Microsc Res Tech 60(5): 503-15.
 This review covers current information about the ability of dental nerves to regenerate and the role of tooth pulp in recruitment of regenerating nerve fibers. In addition, the participation of dental nerves in pulpal injury responses and healing is discussed, especially concerning pulp regeneration and reinnervation after tooth replantation. The complex innervation of teeth is highly asymmetric and guided towards specific microenvironments along blood vessels or in the crown pulp and dentin. Pulpal products such as nerve growth factor are distributed in the same asymmetric gradients as the dentinal sensory innervation, suggesting regulation and recruitment of those nerve fibers by those specific factors. The nerve fibers have important effects on pulpal blood flow and inflammation, while their sprouting and cytochemical changes after tooth injury are in response to altered pulpal cytochemistry. Thus, their pattern and neuropeptide intensity are indicators of pulp status, while their local actions continually affect that status. When denervated teeth are injured, either by pulp exposure on the occlusal surface or by replantation, they have more pulpal necrosis than occurs for innervated teeth. However, small pulp exposures on the side of denervated crowns or larger lesions in germ-free animals can heal well, showing the value of postoperative protection from occlusal trauma or from infection. Current ideas about dental neuroplasticity, neuro-pulpal interactions, and nerve regeneration are related to the overall topics of tooth biomimetics and pulp/dentin regeneration.

Cai, F. and C. J. Helke (2003). "Abnormal PI3 kinase/Akt signal pathway in vagal afferent neurons and vagus nerve of streptozotocin-diabetic rats." Brain Res Mol Brain Res 110(2): 234-44.
 The PI3 (phosphatidylinositol-3) kinase/Akt (protein kinase B) signal pathway is involved in the molecular signaling that regulates retrograde axonal transport of neurotrophins in the nervous system. Previous work showed that a reduced retrograde axonal transport of endogenous nerve growth factor (NGF) and neurotrophin-3 (NT-3) in the vagus nerve of diabetic rats occurred in the presence of normal production of neurotrophins and neurotrophin receptors. To assess the potential involvement of an impaired PI3 kinase/Akt signal pathway in the diabetes-induced reduction in retrograde axonal transport of neurotrophins in the vagus nerve, we characterized diabetes-induced changes in the PI3 kinase/Akt signal pathway in the vagus nerve and vagal afferent neurons. Control and streptozotocin (STZ)-induced diabetic rats with a duration of 16 weeks, kinase assays, Western blotting, and immunocytochemistry were used to show that diabetes resulted in alterations in activity and protein expression of the PI3 kinase/Akt signal pathway in the vagus nerve and vagal afferent neurons. Diabetes caused a significant decrease in enzymatic activity of PI3 kinase and Akt (52 and 36% of control, respectively) in the vagus nerve. The reduced enzymatic activity was not associated with decreased protein expression of the p85 subunit of PI3 kinase, Akt and phosphorylation of Akt (ser473). In contrast, there was a significant increase in the phosphorylation of p70s6 kinase (thr421/ser424) along with a normal protein expression of p70s6 kinase in the vagus nerve of diabetic rats. However, diabetes induced an overall decrease in immunoreactivity of the p85 subunit of PI3 kinase, phospho-Akt (ser473) and phospho-p70s6/p85s6 kinase (thr421/ser424) in vagal afferent neurons. Thus, impaired PI3 kinase/Akt signal pathway may partly account for the reduced retrograde axonal transport of neurotrophins in the vagus nerve of STZ-induced diabetic rats.

Calguner, E., R. Gozil, et al. (2003). "Atrophic and regenerative changes in rabbit mimic muscles after lidocaine and bupivacaine application." Anat Histol Embryol 32(1): 54-9.
 Destruction and denervation atrophy in skeletal muscles caused by the injection of local anaesthetics was investigated by injecting lidocaine or bupivacaine around the rabbit facial nerve to produce facial paralysis. Animals were then sacrificed at 2, 4, 6, and 8 weeks post-injection, and changes in mimic muscle tissue were assessed at each stage by light microscopy and electron microscopy. Atrophic changes were observed at 2-6 weeks after injection, and regeneration started at 6-8 weeks. Compared to bupivacaine, lidocaine caused more dramatic atrophic changes and was associated with slower muscle regeneration.

Calza, L., M. Fernandez, et al. (2003). "Nerve growth factor in the central nervous system: more than neuron survival." Arch Ital Biol 141(2-3): 93-102.
 
Cameron, A. A., G. Vansant, et al. (2003). "Identification of reciprocally regulated gene modules in regenerating dorsal root ganglion neurons and activated peripheral or central nervous system glia." J Cell Biochem 88(5): 970-85.
 Differential gene expression in the rat after injury of dorsal root ganglion neurons in vivo, and simulation injury of Schwann cells and oligodendrocytes in vitro was analyzed using high-density cDNA microarrays. The analyses were carried out to study the genetic basis of peripheral nerve regeneration, and to compare gene regulation in glia of the central (oligodendrocyte) and peripheral (Schwann cell) nervous systems. The genes showing significant differential regulation in the three study groups represented all aspects of cellular metabolism. However, two unexpected observations were made. Firstly, a number of identical genes were differentially regulated in activated Schwann cells, activated oligodendrocytes and regenerating DRG neurons. Specifically, a group of 113 out of 210 genes that were down-regulated in Schwann cells upon lipopolysaccharide (LPS) treatment, were identical to genes up-regulated in the injured, regenerating DRG. Furthermore, a group of 53 out of 71 genes that were down-regulated in interferon gamma (IFN-gamma)/LPS-activated oligodendrocytes, were identical to genes up-regulated in the DRG neurons. Finally, 22 genes were common to these three groups, i.e., down-regulated in activated oligodendrocytes, down-regulated in activated Schwann cells, and up-regulated in regenerating DRG neurons. Secondly, a group of 16 cell-cycle and proliferation-related genes were up-regulated in the DRG following sciatic nerve crush, despite the absence of cells undergoing mitosis in the DRG, or any significant presence of apoptosis-related gene expression. Therefore, it appears that in these three cell types, large sets of genes are reciprocally regulated upon injury and/or activation. This suggests that the activation of the injury-related gene expression program in cell derivatives of the neuroectoderm involves, in part, highly conserved genetic elements.

Campana, W. M., R. R. Myers, et al. (2003). "Identification of PINCH in Schwann cells and DRG neurons: shuttling and signaling after nerve injury." Glia 41(3): 213-23.
 Particularly interesting new cysteine-histidine rich protein (PINCH) is a double zinc finger domain (LIM)-only adapter protein that functions to recruit the integrin-linked kinase (ILK) to sites of integrin activation. Genetic studies have shown that PINCH and ILK are required for integrin signaling. Since integrin activation is associated with Schwann cell migration, neurite outgrowth and regeneration, this study examined PINCH in the normal peripheral nervous system and after chronic constriction injury (CCI) in adult Sprague-Dawley rats. Immunohistochemistry identified PINCH immunoreactivity in cell bodies of dorsal root ganglia (DRG) neurons, axons, satellite cells, and Schwann cells. PINCH immunostaining was localized to the membrane of uninjured DRG cell bodies consistent with its localization at a site of integrin activation. In contrast, 5 days following CCI, PINCH immunostaining was diffuse throughout the DRG cell cytoplasm. Confocal microscopy of primary and transformed Schwann cells localized PINCH in cytoplasmic, perinuclear and nuclear areas. Examination of the PINCH sequence revealed a putative leucine-rich nuclear export signal (NES) and an overlapping basic nuclear localization signal (NLS). To demonstrate nuclear export of PINCH, rabbit anti-PINCH IgG was microinjected into Schwann cell nuclei and allowed to combine with PINCH contained within the nucleus. Immunofluorescence showed that the PINCH and anti-PINCH IgG complex rapidly translocated to the cytoplasm. Treatment with leptomycin B caused nuclear accumulation of PINCH, indicating that the CRM1 pathway mediates nuclear export of PINCH. ILK activity in Schwann cells was enhanced by platelet-derived growth factor (PDGF) and tumor necrosis factor alpha. PINCH immunoprecipitates from PDGF- and TNFalpha-stimulated Schwann cells contained several high-molecular-weight threonine-phosphorylated proteins. Taken together, these results indicate that PINCH is an abundant shuttling/signaling protein in Schwann cells and DRG neurons.

Cao, X., J. Li, et al. (2003). "C3,4 transfer for neurotization of C5,6 nerve roots in brachial plexus injury in a rabbit model." J Reconstr Microsurg 19(4): 265-70.
 To evaluate the root neurotization properties of extraplexal donor nerves, an avulsion injury model of brachial plexus was created and repaired by C 3,4 nerve-root transfers in the rabbit. Eighteen rabbits were divided into three groups. In Group 1 (n = 6), the right C 5,6 nerve roots were avulsed and bridged by a nerve graft taken from the femoral nerve, with C 3,4 as C 3 to C 5 and C 4 to C 6. In Group 2 (n = 6), the right C 5,6 nerve roots were cut and directly sutured end-to-end. Group 3 (n = 6) was a negative group, in which C 5,6 nerve roots were avulsed without repair. All three groups were positively controlled by the contralateral side. Postoperative behavior observation and anatomic, electrophysiologic studies were conducted 4 months later for comparison among groups. Axon existence was observed by acetylcholinesterase staining. Results showed that active motion was not found in all three groups by the end of the study. Extraplexal nerve transfer indeed was able to re-neurotize the avulsed nerve roots down to their target organ, but C 3,4 nerve transfer was weaker than direct end-to-end suture, in terms of neurotization ability. The authors conclude that "root or trunk repair" for avulsion injury of the brachial plexus is possible, provided that the donor nerve has enough fibers and the nerve regeneration ability is increased by modern moleculobiologic techniques.

Carrasco, J., M. Penkowa, et al. (2003). "Role of metallothionein-III following central nervous system damage." Neurobiol Dis 13(1): 22-36.
 We evaluated the physiological relevance of metallothionein-III (MT-III) in the central nervous system following damage caused by a focal cryolesion onto the cortex by studying Mt3-null mice. In normal mice, dramatic astrogliosis and microgliosis and T-cell infiltration were observed in the area surrounding the lesioned tissue, along with signs of increased oxidative stress and apoptosis. There was also significant upregulation of cytokines/growth factors such as tumor necrosis factor-alpha, interleukin (IL)-1 alpha/beta, and IL-6 as measured by ribonuclease protection assay. Mt3-null mice did not differ from control mice in these responses, in sharp contrast to results obtained in Mt1- Mt2-null mice. In contrast, Mt3-null mice showed increased expression of several neurotrophins as well as of the neuronal sprouting factor GAP-43. Thus, unlike MT-I and MT-II, MT-III does not affect the inflammatory response elicited in the central nervous system by a cryoinjury, nor does it serve an important antioxidant role, but it may influence neuronal regeneration during the recovery process.

Carro, E., J. L. Trejo, et al. (2003). "Brain repair and neuroprotection by serum insulin-like growth factor I." Mol Neurobiol 27(2): 153-62.
 The existence of protective mechanisms in the adult brain is gradually being recognized as an important aspect of brain function. For many years, self-repair processes in the post-embryonic brain were considered of minor consequence or nonexistent. This notion dominated the study of neurotrophism. Thus, although the possibility that neurotrophic factors participate in brain function in adult life was prudently maintained, the majority of the studies on the role of trophic factors in the brain were focused on developmental aspects. With the recent recognition that the adult brain keeps a capacity for cell renewal, although limited, a new interest in the regenerative properties of brain tissue has emerged. New findings on the role of insulin-like growth factor I (IGF-I), a potent neurotrophic peptide present at high levels in serum, may illustrate this current trend. Circulating IGF-I is an important determinant of proper brain function in the adult. Its pleiotropic effects range from classical trophic actions on neurons such as housekeeping or anti-apoptotic/ pro-survival effects to modulation of brain-barrier permeability, neuronal excitability, or new neuron formation. More recent findings indicate that IGF-I participates in physiologically relevant neuroprotective mechanisms such as those triggered by physical exercise. The increasing number of neurotrophic features displayed by serum IGF-I reinforces the view of a physiological neuroprotective network formed by IGF-I, and possibly other still uncharacterized signals. Future studies with IGF-I, and hopefully other neurotrophic factors, will surely reveal and teach us how to potentiate the self-reparative properties of the adult brain.

Ceballos, D., N. Lago, et al. (2003). "Role of metallothioneins in peripheral nerve function and regeneration." Cell Mol Life Sci 60(6): 1209-16.
 The physiological role of the metallothionein (MT) family of proteins during peripheral nerve injury and regeneration was examined in Mt1+ 2 and Mt3 knockout (KO) mice. To this end, the right sciatic nerve was crushed, and the regeneration distance was evaluated by the pinch test 2-7 days postlesion (dpl) and electrophysiologically at 14 dpl. The quality of the regeneration was assessed by light microscopy and immunohistochemical methods. The results show that the regeneration distance was greater in the Mt3 KO than in the Mt1+ 2 KO mice, whereas control mice showed intermediate values. Moreover, the number of regenerating axons in the distal tibial nerve was significantly higher in Mt3KO mice than in the other two strains at 14 dpl. Immunoreactive profiles to protein gene product 9.5 were present in the epidermis and the sweat glands of the plantar skin of the hindpaw of the Mt3 KO group. The improved regeneration observed with the Mt3 KO mice was confirmed by compound nerve action potentials that were recorded from digital nerves at 14 dpl only in this group. We conclude that Mt3 normally inhibits peripheral nerve regeneration.

Chafik, D., D. Bear, et al. (2003). "Optimization of Schwann cell adhesion in response to shear stress in an in vitro model for peripheral nerve tissue engineering." Tissue Eng 9(2): 233-41.
 The design of nerve guidance channels (NGCs) is evolving to produce a favorable environment for neural regeneration. We created an in vitro model to evaluate the interactions between three centrally important components of this altered host environment: (1). Schwann cells, (2). substrate, and (3). sustained mechanical stimulus in the form of shear stress with laminar fluid flow. Preconfluent Schwann cells were plated on slides coated either with laminin, poly-D-lysine, type IV collagen, or fibronectin. These slides were placed into custom-designed, parallel-plate, flow chambers and were administered laminar fluid flow at a rate of 15 mL/min for 2 h. Schwann cell adhesion assays demonstrated that laminin (mean, 86.1%; SEM, 4.47%) and fibronectin (mean, 81.7%; SEM, 3.24%) were statistically superior to collagen type IV (mean, 57.7%; SEM, 3.96%) and poly-D-lysine (mean, 58.0%; SEM, 4.97%) (p < 0.001). Fibronectin (mean, 12.20%; SEM, 0.374%) induced statistically greater Schwann cell proliferation than did laminin (mean, 8.14%; SEM, 0.682%) (p < 0.001). Therefore, we recommend that fibronectin should be used as an important component of NGCs with further in vivo studies. As mechanical stress is an integral part of the host environment, our study is the first to incorporate this factor into an in vitro model for peripheral nerve tissue engineering.

Chalfoun, C., T. Scholz, et al. (2003). "Primary nerve grafting: A study of revascularization." Microsurgery 23(1): 60-5.
 It was the purpose of this study to evaluate the revascularization of primary nerve repair and grafts using orthogonal polarization spectral (OPS) (Cytometrix, Inc.) imaging, a novel method for real-time evaluation of microcirculatory blood flow. Twenty male Sprague Dawley rats (250 g) were anesthetized with vaporized halothane and surgically prepared for common peroneal nerve resection. Group I animals (n = 10) underwent primary neurorraphy following transection, utilizing a microsurgical technique with 10-0 nylon suture. Group II (n = 10) animals had a 7-mm segment of nerve excised, reversed, and subsequently replaced as a nerve graft under similar techniques. All animals were evaluated using the OPS imaging system on three portions (proximal, transection site/graft, and distal) of the nerve following repair or grafting. Reevaluation of 5 animals randomly selected from each group using the OPS imaging system was again performed on days 14 and 28 following microsurgical repair/grafting. Values were determined by percent change in vascularity of the common peroneal nerve at 0 hr following surgery. Real-time evaluation of blood flow was utilized as an additional objective criterion. Percent vascularity in group I and II animals increased from baseline in all segments at day 14. By day 28, vascularity in nerves of group I rats decreased in all segments to values below baseline, with the exception of the transection site, which remained at a higher value than obtained directly after surgical repair. In group II animals, vascularity remained above baseline in all segments except the distal segment, which returned to vascularity levels similar to those at 0 hr. Further, occlusion of the vessels demonstrated in the graft and distal segments following initial transection appeared to be corrected. This study suggests that revascularization may occur via bidirectional inosculation with favored proximal vascular growth advancement. The use of real-time imaging offers a unique evaluation of tissues through emerging technologies.

Chan, Y. M., L. W. Yick, et al. (2003). "Inhibition of caspases promotes long-term survival and reinnervation by axotomized spinal motoneurons of denervated muscle in newborn rats." Exp Neurol 181(2): 190-203.
 We examined whether (1) a pan-caspase inhibitor, Boc-D-FMK, exerts long-term neuroprotective effects on spinal motoneurons (MNs) after root avulsion in neonatal rats and (2) whether the rescued spinal MNs regenerate their axons into a peripheral nerve (PN) graft and reinnervate a previously denervated target muscle. Eight weeks after root avulsion, 67% of spinal MNs remained in the Boc-D-FMK-treated group, whereas all MNs died in the sham control group. By 12 weeks postinjury, however, all Boc-D-FMK treated MNs died. In the regeneration experiment, a PN graft was implanted at different times after injury. The animals were allowed to survive for 4 weeks following the operation. Without caspase inhibition, MNs did not regenerate at any time point. In animals treated with Ac-DEVD-CHO, a caspase-3-specific inhibitor, and Boc-D-FMK, 44 and 62% of MNs, respectively, were found to regenerate their axons into a PN graft implanted immediately after root avulsion. When the PN graft was implanted 2 weeks after injury, however, MNs failed to regenerate following Ac-DEVD-CHO treatment, whereas 53% of MNs regenerated their axons into the graft after treatment with Boc-D-FMK. No regeneration was observed when a PN graft was implanted later than 2 weeks after injury. In the reinnervation study, injured MNs and the target biceps muscle were reconnected by a PN bridge implanted 2 weeks after root avulsion with administration of Boc-D-FMK. Eight weeks following the operation, 39% of MNs reinnervated the biceps muscle. Morphologically normal synapses and motor endplates were reformed in the muscle fibers. Collectively, these data provide evidence that injured neonatal motoneurons can survive and reinnervate peripheral muscle targets following inhibition of caspases.

Chao, M. V. (2003). "Neurotrophins and their receptors: a convergence point for many signalling pathways." Nat Rev Neurosci 4(4): 299-309.
 
Chavez-Delgado, M. E., J. Mora-Galindo, et al. (2003). "Facial nerve regeneration through progesterone-loaded chitosan prosthesis. A preliminary report." J Biomed Mater Res 67B(2): 702-11.
 Biodegradable nerve guides have represented new treatment alternatives for nerve repairing. They are gradually biodegradable, exert biological effects directly to the injured nerve, and act as drug- or cell-delivery devices. Furthermore, progesterone (PROG) has been demonstrated to promote injured peripheral nerve regeneration. In this study, it was hypothesized that PROG delivered from chitosan prostheses provides better facial nerve regenerative response than chitosan prostheses with no PROG. As there are no reports on the use of the former as nerve-guide material in the regeneration of injured nerves, this is the main objective of the present work. Chitosan prostheses containing PROG were used to bridge 10-mm gaps in rabbit facial nerves. The regenerated nerves were evaluated 45 days after implantation in animals with the use of light microscopy and morphometric analysis. Gas chromatography was used in order to quantify PROG content in prosthesis prior to and after implantation in subcutaneous tissue at different periods of up to 60 days. In addition, the prosthesis walls were evaluated with histological techniques in order to assess their integrity and the surrounding tissue reaction. Chitosan prostheses allowed PROG release during the time needed for nerve regeneration. At 45 days myelinated nerve fibers were observed in both the proximal and distal stumps. This parameter and the N ratio were higher in the progesterone-treated group when compared to that of the vehicle control. Findings indicate that chitosan prostheses were useful in nerve regeneration, acting as a long-lasting PROG delivery device a faster nerve regeneration.

Chen, Z. L. and S. Strickland (2003). "Laminin gamma1 is critical for Schwann cell differentiation, axon myelination, and regeneration in the peripheral nerve." J Cell Biol 163(4): 889-99.
 Laminins are heterotrimeric extracellular matrix proteins that regulate cell viability and function. Laminin-2, composed of alpha2, beta1, and gamma1 chains, is a major matrix component of the peripheral nervous system (PNS). To investigate the role of laminin in the PNS, we used the Cre-loxP system to disrupt the laminin gamma1 gene in Schwann cells. These mice have dramatically reduced expression of laminin gamma1 in Schwann cells, which results in a similar reduction in laminin alpha2 and beta1 chains. These mice exhibit motor defects which lead to hind leg paralysis and tremor. During development, Schwann cells that lack laminin gamma1 were present in peripheral nerves, and proliferated and underwent apoptosis similar to control mice. However, they were unable to differentiate and synthesize myelin proteins, and therefore unable to sort and myelinate axons. In mutant mice, after sciatic nerve crush, the axons showed impaired regeneration. These experiments demonstrate that laminin is an essential component for axon myelination and regeneration in the PNS.

Chen, J., Y. Tu, et al. (2003). "Heme oxygenase-1 and heme oxygenase-2 have distinct roles in the proliferation and survival of olfactory receptor neurons mediated by cGMP and bilirubin, respectively." J Neurochem 85(5): 1247-61.
 Heme oxygenase (HO) is implicated in protection against oxidative stress, proliferation and apoptosis in many cell types, including neurons. We utilized olfactory receptor neurons (ORNs) as a model to define the roles of HO-1 and HO-2 in neuronal development and survival, and to determine the mediators of these effects. The olfactory system is a useful model as ORNs display neurogenesis post-natally and do not contain nitric oxide synthase (NOS) activity, which could confound results. HO isoforms were expressed in ORNs during embryogenesis and post-natally. Mice null for either HO-1 or HO-2 displayed decreased proliferation of neuronal precursors. However, apoptosis was increased only in HO-2 null mice. Cyclic GMP immunostaining was reduced in ORNs in both genotypes, providing direct evidence that HO mediates cGMP production in vivo. Bilirubin immunostaining was reduced only in HO-2 null mice. These roles for HO-1 and HO-2 were confirmed using detergent ablation of the epithelium to observe increased neurogenesis of ORNs after target disruption in HO null mice. Primary cultures of ORNs revealed that proliferative and survival effects of HO were mediated through cGMP and bilirubin, respectively. These results support a role for HO, the CO-cGMP signaling system and bilirubin in neurodevelopment and in response to injury.

Chen, P., F. Zindy, et al. (2003). "Progressive hearing loss in mice lacking the cyclin-dependent kinase inhibitor Ink4d." Nat Cell Biol 5(5): 422-6.
 Maintenance of the post-mitotic state in the post-natal mammalian brain is an active process that requires the cyclin-dependent kinase inhibitors (CKIs) p19Ink4d (Ink4d) and p27Kip1 (Kip1). In animals with targeted deletions of both Ink4d and Kip1, terminally differentiated, post-mitotic neurons are observed to re-enter the cell cycle, divide and undergo apoptosis. However, when either Ink4d or Kip1 alone are deleted, the post-mitotic state is maintained, suggesting a redundant role for these genes in mature neurons. In the organ of Corti--the auditory sensory epithelium of mammals--sensory hair cells and supporting cells become post-mitotic during embryogenesis and remain quiescent for the life of the animal. When lost as a result of environmental insult or genetic abnormality, hair cells do not regenerate, and this loss is a common cause of deafness in humans. Here, we report that targeted deletion of Ink4d alone is sufficient to disrupt the maintenance of the post-mitotic state of sensory hair cells in post-natal mice. In Ink4d-/- animals, hair cells are observed to aberrantly re-enter the cell cycle and subsequently undergo apoptosis, resulting in progressive hearing loss. Our results identify a novel mechanism underlying a non-syndromic form of progressive hearing loss in mice.

Chen, Y. and R. A. Swanson (2003). "Astrocytes and brain injury." J Cereb Blood Flow Metab 23(2): 137-49.
 Astrocytes are the most numerous cell type in the central nervous system. They provide structural, trophic, and metabolic support to neurons and modulate synaptic activity. Accordingly, impairment in these astrocyte functions during brain ischemia and other insults can critically influence neuron survival. Astrocyte functions that are known to influence neuronal survival include glutamate uptake, glutamate release, free radical scavenging, water transport, and the production of cytokines and nitric oxide. Long-term recovery after brain injury, through neurite outgrowth, synaptic plasticity, or neuron regeneration, is influenced by astrocyte surface molecule expression and trophic factor release. In addition, the death or survival of astrocytes themselves may affect the ultimate clinical outcome and rehabilitation through effects on neurogenesis and synaptic reorganization.

Cheng, M., W. Cao, et al. (2003). "Studies on nerve cell affinity of biodegradable modified chitosan films." J Biomater Sci Polym Ed 14(10): 1155-67.
 Chitosan, a natural polysaccharide that has excellent biocompatibility and biodegradability, can be used as nerve conduit material. The purpose of this work was to study the ability of chitosan and some chitosan-derived materials to facilitate nerve cell attachment, differentiation and growth. The biomaterials studied were chitosan, poly-L-lysine-blended chitosan (CP), collagen-blended chitosan (CC) and albumin-blended chitosan (CA), with collagen control material. Culture of PC12 cells and fetal mouse cerebral cortex (FMCC) cells on these biomaterials was used to evaluate their nerve cell affinity. The composite materials, including CP, CC and CA, had significantly improved nerve cell affinity compared to chitosan, as established by increasing attachment, differentiation and growth of PC12 cells. FMCC cells could also grow better on composite materials than on chitosan. CP exhibited the best nerve cell affinity among these three types of composite material. CP is an even better material in promoting neurite outgrowth than collagen, a substrate that is widely used in tissue engineering, suggesting that CP is a promising candidate material for nerve regeneration.

Cheng, M., J. Deng, et al. (2003). "Study on physical properties and nerve cell affinity of composite films from chitosan and gelatin solutions." Biomaterials 24(17): 2871-80.
 A series of chitosan-gelatin composite films was prepared by varying the ratio of constituents. FT-IR and X-ray analysis showed good compatibility between these two biopolymers. Differential scanning calorimetry (DSC) analysis indicated that the water take-up of chitosan film increased when blended with gelatin. Composite film exhibited a lower Young's modulus and a higher percentage of elongation-at-break compared with chitosan film, especially in wet state. All composite films were hydrophilic materials with water contact angles ranging from 55 degrees to 65 degrees. The results obtained from ELISA indicated the adsorption amount of fibronectin on composite films was much higher than on chitosan film. PC12 cells culture was used to evaluate the nerve cell affinity of materials. The cells cultured on the composite film with 60wt% gelatin differentiated more rapidly and extended longer neurites than on chitosan film. The results suggest that the soft and elastic complex of chitosan and gelatin, which has better nerve cell affinity compared to chitosan, is a promising candidate biomaterial for nerve regeneration.

Choi, D. and G. Raisman (2003). "Immune rejection of a facial nerve xenograft does not prevent regeneration and the return of function: an experimental study." Neuroscience 121(2): 501-7.
 Nerve grafts may be used to repair damaged peripheral nerves and also to facilitate spinal cord regeneration after experimental trauma. Little is known, however, about the possible use of xenografts and the role of immune rejection in the outcome of repair. In rats, excision of a short (7-8 mm) segment of facial nerve at its exit point from the skull base results in a permanent deficit in eye closure in the blink reflex. This deficit can be repaired by transplantation of a segment of either syngeneic rat facial nerve or xenogeneic Balb-C mouse sciatic nerve either with or without cyclosporine immunosuppression. With longer (15-20 mm) transplants, however, restoration of eye closure becomes dependent on cyclosporine administration. Thus, in a situation where nerve repair does not occur without a graft, a host immune attack has an attritional effect which is not sufficient to prevent repair over short distances, but becomes obvious when the regenerating fibres have to cross longer segments of transplanted tissue.

Christianson, J. A., J. T. Riekhof, et al. (2003). "Restorative effects of neurotrophin treatment on diabetes-induced cutaneous axon loss in mice." Exp Neurol 179(2): 188-99.
 Chronic hyperglycemia in diabetes causes a variety of somatosensory deficits, including reduced cutaneous innervation of distal extremities. Deficient neurotrophin support has been proposed to contribute to the development of diabetic neuropathy. Here, studies were carried out in streptozotocin (STZ)-treated mice to determine whether (1) cutaneous innervation deficits develop in response to hyperglycemia, (2) neurotrophin production is altered in the skin, and (3) neurotrophin treatment improves cutaneous innervation deficits. Cutaneous innervation was quantified in the hindlimb skin using antibodies that label nerve growth factor- (NGF) responsive (CGRP), glial cell line-derived neurotrophic factor (GDNF)/neurturin (NTN) -responsive (P2X(3)), or all cutaneous axons (PGP 9.5). Diabetic mice displayed severely reduced cutaneous innervation for all three antibodies in both flank and footpad skin regions, similar to reports of cutaneous innervation loss in human diabetic patients. Qualitative assessment of mRNAs for NGF, GDNF, and NTN demonstrated that these mRNAs were expressed in hindlimb flank and footpad skin from diabetic mice. Next, diabetic mice were then treated intrathecally for 2 weeks with NGF, GDNF, or NTN. NGF treatment failed to improve cutaneous innervation, but stimulated axon branching. In comparison, GDNF and NTN treatment increased cutaneous innervation and axon branching. Our results reveal that similar to human diabetic patients, STZ-induced diabetes significantly reduces hindlimb cutaneous innervation in mice. Importantly, intrathecal treatment using GDNF or NTN strongly stimulated axon growth and branching, suggesting that administration of these trophic factors can improve cutaneous innervation deficits caused by diabetes.

Colman, D., C. Lubetzki, et al. (2003). "Multiple paths towards repair in multiple sclerosis." Trends Neurosci 26(2): 59-61.
 Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS, affecting approximately 1/1000 individuals in the Western world. Available treatments limit CNS inflammation and strategies to repair damage in the CNS offer the potential of recovery of both tissue and function. With further fundamental knowledge developing, this area is ripe for 'translation' to clinical application.

Constantinidis, J., A. Akbarian, et al. (2003). "Effects of immediate and delayed facial-facial nerve suture on rat facial muscle." Acta Otolaryngol 123(8): 998-1003.
 OBJECTIVE: To investigate regeneration of the mimic musculature after delayed facial nerve repair. MATERIALS AND METHOD: In 30 rats the facial nerve on the right side was resected and immediately repaired with an end-to-end anastomosis. The entire levator labii muscle was removed on the right side and histochemically and morphometrically analyzed at 7, 14, 21, 28, 90 and 180 days after immediate nerve repair. In a further 20 rats, reinnervation was performed after 4 weeks in a further operation and the muscle was assessed at 14, 28, 90 and 180 days. Seven muscles of four normal rats were used as controls. RESULTS: Three muscle fiber types could be identified by comparative histochemical analysis of two enzymes of succinate dehydrogenase (SDH) and m-ATPase: oxidative glycolytic (FOG) fibers, fast glycolytic (FG) fibers and intermediate muscle fibers that were designated SDH-INT. The number of fibers and the frequency distribution of single-fiber cross-sectional areas were determined for each type of fiber. No significant difference in the cross-sectional area of all fiber types was noted after 180 days when comparing immediate and delayed end-to-end sutures. In contrast, comparison of the fiber-type composition showed a significant increase in the number of FG fibers in the delayed suture, at the expense of FOG fibers. After immediate reinnervation the muscle approximately attained its natural fiber-type composition, whereas after delayed reinnervation the muscle showed an overall loss of oxidative capacity and differentiation towards phasic activity. CONCLUSION: Changes in fiber-type composition following delayed nerve suture are irreversible and have specific effects on the precise function of the muscle. Immediate nerve repair improves axonal reinnervation.

Corey, J. M. and E. L. Feldman (2003). "Substrate patterning: an emerging technology for the study of neuronal behavior." Exp Neurol 184 Suppl 1: S89-96.
 Extracellular matrix (ECM) proteins and cell-cell adhesion molecules (CAM) play important roles in neuronal development and differentiation. In the investigation of these roles, patterned substrates have proven to be a notably useful tool. Photolithographic and microprinting techniques can be used to make patterns of ECMs, CAMs, amino acids, and organofunctional groups for culturing neurons and other cell types. Experiments performed using these substrates have provided unique insights into the roles of cell-substratum adhesion, cell shape, and ECM composition on important cell functions, including survival, migration, neurite outgrowth, and development of polarity. Patterns may also be designed to localize cell bodies and confine their processes to predetermined areas of a substrate. Finally, the behavior of neurons on patterned substrates may prove helpful in the design of scaffoldings and nerve guides tailored for regeneration and repair of the nervous system.

Corti, S., F. Locatelli, et al. (2003). "Neuronal generation from somatic stem cells: current knowledge and perspectives on the treatment of acquired and degenerative central nervous system disorders." Curr Gene Ther 3(3): 247-72.
 Stem cell transplantation through cell replacement or as vector for gene delivery is a potential strategy for the treatment of neurodegenerative diseases. Several studies have reported the transdifferentiation of different somatic stem cells into neurons in vitro or after transplantation into animal models. This observation has pointed out the perspective of using an ethical and accessible cell source to "replace" damaged neurons or provide support to brain tissue. However, recent findings such as the cell fusion phenomenon have raised some doubts about the real existence of somatic stem cell plasticity. In this review, we will discuss current evidence and controversial issues about the neuroneogenesis from various sources of somatic cells focusing on the techniques of isolation, expansion in vitro as well as the inductive factors that lead to transdifferentiation in order to identify the factors peculiar to this process. The morphological, immunochemical, and physiological criteria to correctly judge whether the neuronal transdifferentation occurred are critically presented. We will also discuss the transplantation experiments that were done in view of a possible clinical therapeutic application. Animal models of stroke, spinal cord and brain trauma have improved with Mesenchymal Stem Cells or Bone Marrow transplantation. This improvement does not seem to depend on the replacement of the lost neurons but may be due to increased expression levels of neurotrophic factors, thus suggesting a beneficial effect of somatic cells regardless of transdifferentiation. Critical understanding of available data on the mechanisms governing the cell fate reprogramming is a necessary achievement toward an effective cell therapy.

Cuadros-Romero, M. (2003). "Nerve regeneration using polyglicolic acid as alternative to grafting." J Hand Surg [Am] 28 Suppl 1: 17.
 
Csoknya, M., J. Barna, et al. (2003). "Reorganization of monoaminergic systems in the earthworm, Eisenia fetida, following brain extirpation." J Exp Zoolog Part A Comp Exp Biol 296(1): 18-29.
 The present study describes the major aspects of how monoaminergic (serotonin, dopamine) systems change in the course of regeneration of the brain in the earthworm (Eisenia fetida), investigated by immunocytochemistry, HPLC assay, and ligand binding. Following brain extirpation, the total regeneration time is about 80 days at 10 degrees C. On the 3rd postoperative day serotonin, and on the 11th postoperative day tyrosine hydroxylase-immunoreactive neurons can be observed in the wound tissue. Thereafter the number of the immunoreactive cells increases gradually, and by the 76th-80th postoperative days all serotonin- and tyrosine hydroxylase-immunopositive neurons can be found in their final positions, similarly to those observed in the intact brain. Labeled neurons located in the dorsal part of the regenerated brain appear earlier than the cells in lateral and ventral positions. Both serotonin- and tyrosine hydroxylase-immunoreactive neurons of the newly formed brain seem to originate from undifferentiated neuroblasts situated within and around the ventral ganglia and the pleura. Dopaminergic (tyrosine hydroxylase-immunoreactive) elements may additionally derive from the proliferation of neurons localized in the subesophageal ganglion and the pharyngeal nerve plexus. Following brain extirpation, both serotonin and dopamine levels, assayed by HPLC, first increase in the subesophageal ganglion; by the 25th day of regeneration, the monoamine content decreases in it and increases in the brain. Hence it is suggested that monoamines are at least partly transported from this ganglion to the regenerating brain. At the same time, (3)H-LSD binding can be detected in the regenerating brain from the 3rd postoperative day, showing a continuous increase until the 80th postoperative day, suggesting a guiding role of postsynaptic elements in the monoaminergic reinnervation of the newly formed brain.

Cui, S. S., C. P. Yang, et al. (2003). "Valproic acid enhances axonal regeneration and recovery of motor function after sciatic nerve axotomy in adult rats." Brain Res 975(1-2): 229-36.
 It has recently been demonstrated that valproic acid (VPA) robustly promotes neurite outgrowth, activates the extracellular signal regulated kinase pathway, and increases growth cone-associated protein 43 and bcl-2 levels in cultured human neuroblastoma SH-SY5Y cells. We hypothesized that VPA could also enhance peripheral nerve regeneration in adult animals. To test this hypothesis, we examined the effects of VPA (300 mg/kg daily for 16 weeks) on sciatic axonal regeneration following single or conditional axotomies in rats. The results showed that in VPA-treated rats there was a significant increase in the total numbers of regenerated myelinated nerve fibers and reinnervated muscle fibers in comparison with those rats not treated with VPA. As measured by sciatic function index and toe spread index, the motor function of the reinnervated hind limbs of rats receiving single axotomy without VPA treatment significantly improved at week 8 and reached plateau levels at about week 11, whereas the motor function of the reinnervated hind limbs of rats receiving single axotomy plus VPA and rats receiving conditional axotomy with or without VPA treatment significantly improved at week 4 and reached plateau levels at about week 8; there was no significant difference of the motor function among the three later groups. The results demonstrated that VPA is able to enhance sciatic nerve regeneration and recovery of motor function in adult rats, suggesting the potential clinical application of VPA for the treatment of peripheral nerve injury in humans.

Cui, Q., M. A. Pollett, et al. (2003). "A new approach to CNS repair using chimeric peripheral nerve grafts." J Neurotrauma 20(1): 17-31.
 We have examined whether transplanted freeze-thawed peripheral nerve (PN) sheaths repopulated ex vivo with purified adult Schwann cells (SCs) support the regeneration of adult rat retinal ganglion cell (RGC) axons. Cultured adult SCs were derived from donor rats or from the host animals themselves. We also transplanted PN sheaths filled with neonatal SCs or donor adult olfactory ensheathing glia (OEG). 100,000 cells were injected into 1.5-cm lengths of freeze-thawed PN. After 2 days in culture, repopulated PN segments were grafted onto the transected optic nerve of adult Fischer rats. Three weeks later, 6% fluorogold (FG) was applied to distal PN. Retrogradely labeled RGCs were counted in retinal wholemounts and PN grafts were processed for immunohistochemistry. As expected, there was no RGC axon regeneration in cell-free grafts. Regrowth was also absent in neonatal SC- and adult OEG-filled grafts, which contained only small numbers of surviving donor cells. Many cells were, however, seen in adult SC repopulated PN grafts, intermingled with pan-neurofilament(+) and GAP-43(+) fibers. SCs were aligned along the grafts and were S-100(+), p75(+). Ultrastructurally, SCs were associated with myelinated and unmyelinated axons. Hundreds of FG-labeled RGCs were seen in retinas of rats with congeneic or allogeneic PN sheaths repopulated with either donor or autologous (host-derived) adult SCs. Intraocular CNTF injections significantly increased the number of regenerating RGCs in donor and autologous adult SC groups. The use of chimeric grafts to bridge CNS tissue defects could provide a clinical alternative to using multiple PN autografts, the harvesting of which would exacerbate peripheral dysfunction in already injured patients.

Cui, Q., H. K. Yip, et al. (2003). "Intraocular elevation of cyclic AMP potentiates ciliary neurotrophic factor-induced regeneration of adult rat retinal ganglion cell axons." Mol Cell Neurosci 22(1): 49-61.
 In vitro, cyclic AMP (cAMP) elevation alters neuronal responsiveness to diffusible growth factors and myelin-associated inhibitory molecules. Here we used an established in vivo model of adult central nervous system injury to investigate the effects of elevated cAMP on neuronal survival and axonal regeneration. We studied the effects of intraocular injections of neurotrophic factors and/or a cAMP analogue (CPT-cAMP) on the regeneration of axotomized rat retinal ganglion cell (RGC) axons into peripheral nerve autografts. Elevation of cAMP alone did not significantly increase RGC survival or the number of regenerating RGCs. Ciliary neurotrophic factor increased RGC viability and axonal regrowth, the latter effect substantially enhanced by coapplication with CPT-cAMP. Under these conditions over 60% of surviving RGCs regenerated their axons. Neurotrophin-4/5 injections also increased RGC viability, but there was reduced long-distance axonal regrowth into grafts, an effect partially ameliorated by cAMP elevation. Thus, cAMP can act cooperatively with appropriate neurotrophic factors to promote axonal regeneration in the injured adult mammalian central nervous system.

Curtis, M. A., E. B. Penney, et al. (2003). "Increased cell proliferation and neurogenesis in the adult human Huntington's disease brain." Proc Natl Acad Sci U S A 100(15): 9023-7.
 Neurogenesis has recently been observed in the adult human brain, suggesting the possibility of endogenous neural repair. However, the augmentation of neurogenesis in the adult human brain in response to neuronal cell loss has not been demonstrated. This study was undertaken to investigate whether neurogenesis occurs in the subependymal layer (SEL) adjacent to the caudate nucleus in the human brain in response to neurodegeneration of the caudate nucleus in Huntington's disease (HD). Postmortem control and HD human brain tissue were examined by using the cell cycle marker proliferating cell nuclear antigen (PCNA), the neuronal marker beta III-tubulin, and the glial cell marker glial fibrillary acidic protein (GFAP). We observed a significant increase in cell proliferation in the SEL in HD compared with control brains. Within the HD group, the degree of cell proliferation increased with pathological severity and increasing CAG repeats in the HD gene. Most importantly, PCNA+ cells were shown to coexpress beta III-tubulin or GFAP, demonstrating the generation of neurons and glial cells in the SEL of the diseased human brain. Our results provide evidence of increased progenitor cell proliferation and neurogenesis in the diseased adult human brain and further indicate the regenerative potential of the human brain.

Daniele, H. R. and L. Aguado (2003). "Early compensatory sensory re-education." J Reconstr Microsurg 19(2): 107-10; discussion 111-2.
 After a neurorrhaphy, there will be a distal disconnection between the cortex and skin receptors, along with interruption of sensibility information. This report demonstrates the efficacy of a new sensory re-education program for achieving optimal sensation in a relatively short time. Between 1999 and 2001, in the authors' Hand Rehabilitation Department, 11 patients with previous neurorrhaphy were subjected to a program of early "compensatory sensory re-education." Lesions were caused by clean cut. There were 13 primary digital nerve procedures, 12 at the distal palmar MP level, and one at the radial dorsal branch of the index (just after emerging from the common digital nerve). The technique of compensatory sensory re-education was based on a previous, but modified, sensory re-education method. In order to evaluate the results in the compensatory sensory re-education series described, additional tests for evaluation of achieved functional sensibility were used. The authors' best results were achieved in a maximum of 8 weeks (4-8 weeks), much less time than with the original method (1-2 years). Using the British classification, it was possible to compare the achieved levels of sensibility and the time required for optimal results. The different methods of sensibility re-education may be similar, but with the authors' compensatory sensory re-education method, substantial time is saved.

David, S. and S. Lacroix (2003). "Molecular approaches to spinal cord repair." Annu Rev Neurosci 26: 411-40.
 Axon growth inhibitors associated with myelin and the glial scar contribute to the failure of axon regeneration in the injured adult mammalian central nervous system (CNS). A number of these inhibitors, their receptors, and signaling pathways have been identified. These inhibitors can now be neutralized by a variety of approaches that point to the possibility of developing new therapeutic strategies to stimulate regeneration after spinal cord injury.

de Buys Roessingh, A. S. and O. Reinberg (2003). "Open or closed pinning for distal humerus fractures in children?" Swiss Surg 9(2): 76-81.
 INTRODUCTION: In children, the choice between percutaneous pinning (PP) and open pinning fixation (OPF) for the surgical treatment of fractures of the distal humerus remains controversial, especially the PP method for internal humeral condylar (IHC) fractures. PATIENTS AND METHODS: Eighty fractures of the distal humerus in children were treated surgically in our hospital over a ten year period. 47% (n = 38) were supracondylar (SC), 20% (n = 16) comminuted (COM), 18% (n = 14) internal humeral condylar (IHC), and 15% (n = 12) lateral humeral condylar (LHC). We used PP, OPF and three times osteosynthesis with screws. RESULTS: In comparison to OPF, PP reduced the length of hospitalization in SC fractures (2.8 versus 6.1 days) and IHC fractures (2.4 versus five days). It reduced the risk of extension deficiency (11.1% versus 15%) and of cubitus valgus (0% versus 20%) in SC fractures, and of cubitus varus in IHC fractures (0% versus 11.1%). However it induced a higher rate of cubitus valgus (11.1% versus 20%) in IHC fractures, one persistent neurological motor deficiency (radial nerve) and four cases of transitional neurological involvement (ulnar nerve). CONCLUSIONS: PP is a good surgical method for SC and for also for IHC fractures, if performed by experienced surgeons so as to avoid neurological damage.

De Jonge, R. R., I. N. Van Schaik, et al. (2003). "Expression of complement components in the peripheral nervous system." Hum Mol Genet.
 We have generated a SAGE (serial analysis of gene expression) library of normal sciatic nerve and found tags encoding for mRNAs of the complement system highly represented. RNA (RT-PCR and Northern blot hybridisation) and protein (Western blot analysis and immunohistochemistry) studies confirmed these findings. High expression of classical pathway components, alternative pathway components and inhibitory components was observed in specific regions of the sciatic nerve. The first components of complement were found in axons, whereas the inhibitory components were detected in the perineurium, thereby protecting the nerve from a complement attack. Immunoreactivity towards activated complement factors was noted in post traumatic neuromas and after acute crush injury, which exemplify nerve regeneration and degeneration. We propose that local production of complement in the peripheral nervous system participates in the protection of healthy nerve and is needed for efficient clearance of myelin after injury: a prerequisite for normal regeneration and remyelination of the peripheral nerve.

Deda, G., H. Caksen, et al. (2003). "A case of Marin-Amat syndrome." Genet Couns 14(1): 115-7.
 
Degidi, M., G. Petrone, et al. (2003). "Bone contact around acid-etched implants: a histological and histomorphometrical evaluation of two human-retrieved implants." J Oral Implantol 29(1): 13-8.
 The surface characteristics of dental implants play an important role in their clinical success. One of the most important surface characteristics of implants is their surface topography or roughness. Many techniques for preparing dental implant surfaces are in clinical use: turning, plasma spraying, coating, abrasive blasting, acid etching, and electropolishing. The Osseotite surface is prepared by a process of thermal dual etching with hydrochloric and sulfuric acid, which results in a clean, highly detailed surface texture devoid of entrapped foreign material and impurities. This seems to enhance fibrin attachment to the implant surface during the clotting process. The authors retrieved 2 Osseotite implants after 6 months to repair damage to the inferior alveolar nerve. Histologically, both implants appeared to be surrounded by newly formed bone. No gaps or fibrous tissues were present at the interface. The mean bone-implant contact percentage was 61.3% (+/- 3.8%).

Deininger, S. O., L. Rajendran, et al. (2003). "Identification of teleost Thy-1 and association with the microdomain/lipid raft reggie proteins in regenerating CNS axons." Mol Cell Neurosci 22(4): 544-54.
 During regeneration, retinal ganglion cell axons in fish upregulate a cell surface protein that is recognized by the monoclonal antibody (mAB) M802. M802 antigen appeared to be linked to the intracellular, membrane-associated lipid raft/microdomain proteins reggie-1 and reggie-2 that were previously shown to be reexpressed in axon-regenerating neurons [Development 124 (1997), 577]. Here, we report the isolation of the M802 antigen and its identification as the teleost homolog of mammalian Thy-1. Fish Thy-1 is detected in the same detergent-insoluble lipid raft fractions from a fibroblast cell line and from axon regenerating retinae as reggie-1 and 2. Importantly, mAB M802 coimmunoprecipitates reggie-1 and 2 from this lipid raft fraction, implying that fish Thy-1 and reggies interact. This correlates with their colocalization in growing cell processes after M802 antigen/Thy-1 activation with mAB M802. These findings suggest a role of clustered M802 antigen/Thy-1 in reggie raft microdomains for cell growth and axon regeneration.

DeLucia, T. A., J. J. Conners, et al. (2003). "Use of a cell line to investigate olfactory ensheathing cell-enhanced axonal regeneration." Anat Rec 271B(1): 61-70.
 Olfactory ensheathing cells (OECs), a unique type of macroglia required for normal olfactory axonal regeneration throughout the lifetime of an individual, have been shown to have regeneration-enhancing properties when used to treat various neuronal injuries. Availability of OECs is a hurdle facing future clinical use of the cells for spinal cord injury (SCI) therapy. The number of OECs that can realistically be harvested from each animal is limited, and ensuring a pure cell population is difficult. We have begun to characterize a nonsyngeneic strain of OECs, i.e., from a homogenous OEC clonal cell line (nOECs). The purpose of this study was to determine whether nOECs have the same properties and provide the same functional recovery after SCI, as primary cultures of OECs. The results indicate that nOECs survive in vivo, produce growth-promoting proteins, and possess regeneration-promoting capabilities. Spinal cord injured rats that were treated with nOECs performed significantly better on functional tests than injured control animals beginning at 5 weeks after operation. In summary, evidence of nOEC regeneration-promoting capabilities suggests that this cell line can be used as potential therapy in SCI research.

Dervan, A. G. and B. L. Roberts (2003). "Reaction of spinal cord central canal cells to cord transection and their contribution to cord regeneration." J Comp Neurol 458(3): 293-306.
 After transection, the spinal cord of the eel Anguilla quickly regrows and reconnects, and function recovers. We describe here the changes in the central canal region that accompany this regeneration by using serial semithin plastic sections and immunohistochemistry. The progress of axonal regrowth was followed in material labeled with DiI. The canal of the uninjured cord is surrounded by four cell types: S-100-immunopositive ependymocytes, S-100- and glial fibrillary acidic protein (GFAP)-immunopositive tanycytes, vimentin-immunopositive dorsally located cells, and lateral and ventral liquor-contacting neurons, which label for either gamma-aminobutyric acid (GABA) or tyrosine hydroxylase (TH). After cord transection, a new central canal forms rapidly as small groups of cells at the leading edges of the transection create flat "plates" that serve as templates for subsequent formation of the lateral and dorsal walls. Profile counts and 5-bromo-2'-deoxyuridine immunohistochemistry indicate that these cells are dividing rapidly during the first 20 days of the repair process. The newly formed canal, which bridges the transection by day 10 but is not complete until about day 20, is greatly enlarged (</=100 times) and is dominated by ependymocytes that are vimentin immunopositive, but cells expressing GABA, TH, and GFAP do not appear until days 11, 13, and 16, respectively. The proliferating ependyma do not provide a supportive scaffold for the regrowing axons, inasmuch as some have crossed the bridge before the canal has formed. However, their modified phenotype suggests a role, possibly trophic, for the central canal region following injury.

Desbarats, J., R. B. Birge, et al. (2003). "Fas engagement induces neurite growth through ERK activation and p35 upregulation." Nat Cell Biol 5(2): 118-25.
 Fas (also known as CD95), a member of the tumour-necrosis receptor factor family of 'death receptors', can induce apoptosis or, conversely, can deliver growth stimulatory signals. Here we report that crosslinking Fas on primary sensory neurons induces neurite growth through sustained activation of the extracellular-signal regulated kinase (ERK) pathway and the consequent upregulation of p35, a mediator of neurite outgrowth. In addition, functional recovery after sciatic nerve injury is delayed in Fas-deficient lpr mice and accelerated by local administration of antibodies against Fas, which indicates that Fas engagement may contribute to nerve regeneration in vivo. Our findings define a role for Fas as an inducer of both neurite growth in vitro and accelerated recovery after nerve injury in vivo.

Dieringer, N. (2003). "Activity-Related Postlesional Vestibular Reorganization." Ann N Y Acad Sci 1004: 50-60.
 The synaptic convergence patterns of semicircular canal and macular afferent nerve inputs onto second-order vestibular neurons reorganize in adult frogs after a change in the activity of vestibular nerve afferent fibers. Axotomized afferent nerve fibers become silent after a vestibular nerve lesion, and second-order vestibular target neurons become disfacilitated. These changes initiate an activity-related process that was studied in detail in vitro two months after a section of the ramus anterior (RA) of N. VIII. The postlesional reaction results in an expansion of signals, preferentially from intact, remaining afferent nerve fibers, but also from excitatory commissural and spinal ascending fibers. This process of expansion takes weeks, is graded in its extent, and reversible in case of a nerve regeneration, but is not competitive, i.e., the synaptic contacts from axotomized afferent nerve fibers are maintained without a change in their efficacy. Postlesional synaptic reorganization in the brainstem is restricted to the operated side, underlies the improved responsiveness of disfacilitated second-order vestibular neurons, but also their altered spatial response tuning. The functional consequences of this reorganization were studied in vivo two months after RA nerve section by recording abducens nerve responses during linear or angular accelerations. The vector orientations of best responses of the abducens nerve of chronic RA frogs evoked by linear or angular acceleration differed from the vector orientations of controls. In chronic RA frogs, linear acceleration evoked contralesional abducens nerve responses that originated from the utricle on the intact side and from the lagena, a vertical macular organ in frogs. Such an inadequate lagenar response component was absent in controls and in the ipsi-lesional abducens nerve of chronic RA frogs. Similar differences were detected in the direction of abducens nerve responses of chronic RA frogs during angular acceleration. Thus, compensatory vestibulo-ocular reflexes of chronic RA frogs became more symmetric in gain, but less precise in direction.

Diiulio, R. (2003). "The new alternatives." Rehab Manag 16(6): 38-41, 50.
 
Dolbeare, D. and J. D. Houle (2003). "Restriction of axonal retraction and promotion of axonal regeneration by chronically injured neurons after intraspinal treatment with glial cell line-derived neurotrophic factor (GDNF)." J Neurotrauma 20(11): 1251-61.
 The response of supraspinal neurons to acute or delayed treatment with GDNF following a spinal cord injury was examined. A cervical level 3 hemisection lesion cavity was created by tissue aspiration in adult, female rats. In one experiment gel foam saturated with GDNF was placed into the lesion cavity immediately after injury to determine if the extent of axonal retraction was affected by neurotrophic factor treatment. One week prior to sacrifice animals received a microinjection of biotinylated dextran amine (BDA) into the red nucleus and reticular formation to label descending spinal pathways by anterograde transport mechanisms. Animals were sacrificed 1 or 4 weeks after injury and treatment with GDNF. The terminal end of injured BDA-labeled rubrospinal and reticulospinal tract axons was identified and the distance from the lesion was measured. In comparison to PBS-treated animals, GDNF-treatment resulted in a significant decrease in the extent of axonal retraction of both rubrospinal and reticulospinal tract axons at 1 week after spinal cord injury for both tracts. At 4 weeks after injury the mean distance from the lesion was less than 240 microm following GDNF-treatment for both tracts, compared to over 480 microm following PBS-treatment. In the second experiment injured supraspinal neurons were labeled by retrograde transport of True Blue that had been placed into the lesion cavity. One month later scar tissue was removed from the cavity by aspiration to enlarge the cavity by approximately 500 microm in a rostral direction. GDNF-saturated gel foam was placed into the cavity for 60 min prior to apposition of an autologous peripheral nerve (PN) graft to the rostral cavity wall. One month later Nuclear Yellow was applied to the distal end of the PN graft and animals were sacrificed after 2 days. The number of supraspinal neurons containing both True Blue and Nuclear Yellow was counted as a measure of axonal regeneration by chronically injured neurons. There was a seven-fold increase in the number of regenerating neurons after GDNF-treatment, with the majority (65%) of dual-labeled neurons located within the reticular formation. These results indicate that GDNF has neuroprotective effects when provided acutely after injury and promotes axonal regeneration when provided in a chronic injury situation.

Donnerer, J. (2003). "Regeneration of primary sensory neurons." Pharmacology 67(4): 169-81.
 Primary sensory neurons have an inherent capacity for regeneration of their cut, crushed, or chemically lesioned axons. This capacity is displayed to a much greater extent after lesions of the peripheral axons than after lesions of their centrally directed axons. Additionally, the surrounding tissue determines to a significant extent the degree of recovery: whereas the peripheral nerve tissue provides neurotrophic support and a favorable environment for axonal growth, the central terminals of primary sensory neurons face a non-permissive and inhibitory glial tissue. Mechanical lesions of the peripheral axons of dorsal root ganglion (DRG) sensory neurons can be repaired by the intrinsic regenerative capacity of the neuron itself, when outgrowing axons from the proximal stump are able to transverse the tissue scar and reach the distal stump of the nerve. Bridging the gap with an autologous nerve graft or a short artificial graft filled with nerve growth factor (NGF) can improve recovery. Neurotoxic lesions of the axon terminals are effectively recovered by intermittent local or systemic NGF injections. A recovery from a diabetic sensory neuropathy probably requires the continuous delivery of NGF or additional neurotrophic factors. A recovery from a dorsal rhizotomy or from a dorsal column lesion can possibly be achieved by the concomitant transgene-mediated overexpression of neurotrophins, the transformation of the DRG neuron cells to a competence for regrowth, and the counteraction of the growth-inhibitory nature of the central nervous system tissue.

Duan, Y., S. J. Haugabook, et al. (2003). "Methylene blue blocks cGMP production and disrupts directed migration of microglia to nerve lesions in the leech CNS." J Neurobiol 57(2): 183-92.
 Migration and accumulation of microglial cells at sites of injury are important for nerve repair. Recent studies on the leech central nervous system (CNS), in which synapse regeneration is successful, have shown that nitric oxide (NO) generated immediately after injury by endothelial nitric oxide synthase (eNOS) stops migrating microglia at the lesion. The present study obtained results indicating that NO may act earlier, on microglia migration, and aimed to determine mechanisms underlying NO's effects. Injury induced cGMP immunoreactivity at the lesion in a pattern similar to that of eNOS activity, immunoreactivity, and microglial cell accumulation, which were all focused there. The soluble guanylate cyclase (sGC) inhibitor methylene blue (MB) at 60 microM abolished cGMP immunoreactivity at lesions and blocked microglial cell migration and accumulation without interfering with axon conduction. Time-lapse video microscopy of microglia in living nerve cords showed MB did not reduce cell movement but reduced directed movement, with significantly more cells moving away from the lesion or reversing direction and fewer cells moving toward the lesion. The results indicate a new role for NO, directing the microglial cell migration as well as stopping it, and show that NO's action may be mediated by cGMP.

Dubreuil, C. I., M. J. Winton, et al. (2003). "Rho activation patterns after spinal cord injury and the role of activated Rho in apoptosis in the central nervous system." J Cell Biol 162(2): 233-43.
 Growth inhibitory proteins in the central nervous system (CNS) block axon growth and regeneration by signaling to Rho, an intracellular GTPase. It is not known how CNS trauma affects the expression and activation of RhoA. Here we detect GTP-bound RhoA in spinal cord homogenates and report that spinal cord injury (SCI) in both rats and mice activates RhoA over 10-fold in the absence of changes in RhoA expression. In situ Rho-GTP detection revealed that both neurons and glial cells showed Rho activation at SCI lesion sites. Application of a Rho antagonist (C3-05) reversed Rho activation and reduced the number of TUNEL-labeled cells by approximately 50% in both injured mouse and rat, showing a role for activated Rho in cell death after CNS injury. Next, we examined the role of the p75 neurotrophin receptor (p75NTR) in Rho signaling. After SCI, an up-regulation of p75NTR was detected by Western blot and observed in both neurons and glia. Treatment with C3-05 blocked the increase in p75NTR expression. Experiments with p75NTR-null mutant mice showed that immediate Rho activation after SCI is p75NTR dependent. Our results indicate that blocking overactivation of Rho after SCI protects cells from p75NTR-dependent apoptosis.

Dunlop, S. A. (2003). "Axonal sprouting in the optic nerve is not a prerequisite for successful regeneration." J Comp Neurol 465(3): 319-34.
 Axonal sprouting, the production of axons additional to the parent one, occurs during optic nerve regeneration in goldfish and the frog Rana pipiens, with numbers of regenerate axons exceeding normal values four- to sixfold (Murray [1982] J. Comp. Neurol. 209:352-362; Stelzner and Strauss [1986] J. Comp. Neurol. 245:83-103). To determine whether axonal sprouting is a prerequisite for regeneration, the frog Litoria moorei was examined, a species that undergoes successful optic nerve regeneration but with a different time course compared with R. pipiens. Sprouting was assessed, as in goldfish and R. pipiens, from electron microscopic counts between the lesion and chiasm. However, disconnected axons that persist after axotomy would have falsely elevated the counts. The suspected overlap of these two axon populations was confirmed by labeling regenerate axons anterogradely with DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate) and disconnected ones retrogradely with DiA (4-4-dihexadecylaminostyrl 1-N methylpyridinium iodide). Numbers of disconnected axons were estimated after preventing regeneration and subtracted from numbers in regenerate nerves. Throughout, the total number of regenerate axons was approximately one third lower than normal (P < 0.05) supporting a previous finding of minimal axonal sprouting in L. moorei (Dunlop et al. [2002] J. Comp. Neurol. 446:276-287). The validity of the subtractive electron microscopic method was confirmed by retrograde labeling to estimate numbers of retinal ganglion cells whose axons had crossed the lesion; values were approximately one third lower than normal. The data suggest that sprouting is not essential for either axon outgrowth or topographic map refinement.

Duprey-Diaz, M. V., J. M. Blagburn, et al. (2003). "Neurotrophin-3 and TrkC in the frog visual system: changes after axotomy." Brain Res 982(1): 54-63.
 Neurotrophins are potent regulators of the survival of different neuronal populations in the CNS. Little is known of the immunodistribution of neurotrophin-3 (NT-3) and tyrosine kinase C (TrkC) receptor in the frog visual system, which can successfully regenerate and recover vision after injury. In this study we show that both NT-3 and TrkC are present in the frog retina and tectum, and that their distribution changes after optic nerve transection. Both NT-3 and TrkC are present in the ganglion cell layer, inner nuclear layer, nerve fiber layer and outer plexiform layer, and in Muller cells of control retinas. Quantification of identified RGCs shows that there are only small changes in the proportion, or intensity, of NT-3 immunostained cells surviving after axotomy and regeneration. Muller cell staining, however, is increased. TrkC staining in the retina does not change after axotomy. In the tectum, NT-3 immunoreactivity is present in the retinorecipient layer 9, and in radial processes of neurons and ependymoglia. TrkC is present in ependymoglia and in tectal neurons. After axotomy or colchicine treatment fewer NT-3-immunoreactive processes are present in layer 9 and there is decreased staining of tectal neurons. These data are consistent with the hypothesis that NT-3 is synthesized in the retina and anterogradely transported to the tectum. TrkC immunostaining, on the other hand, increases in tectal cells after optic nerve transection, suggesting that it may be regulated by the supply of NT-3 from the retina.

Echeverri, K. and E. M. Tanaka (2003). "Electroporation as a tool to study in vivo spinal cord regeneration." Dev Dyn 226(2): 418-25.
 Tailed amphibians such as axolotls and newts have the unique ability to fully regenerate a functional spinal cord throughout life. Where the cells come from and how they form the new structure is still poorly understood. Here, we describe the development of a technique that allows the visualization of cells in the living animal during spinal cord regeneration. A microelectrode needle is inserted into the lumen of the spinal cord and short rapid pulses are applied to transfer the plasmids encoding the green or red fluorescent proteins into ependymal cells close to the plane of amputation. The use of small, transparent axolotls permits imaging with epifluorescence and differential interference contrast microscopy to track the transfected cells as they contribute to the spinal cord. This technique promises to be useful in understanding how neural progenitors are recruited to the regenerating spinal cord and opens up the possibility of testing gene function during this process.

Edstrom, A. and P. A. Ekstrom (2003). "Role of phosphatidylinositol 3-kinase in neuronal survival and axonal outgrowth of adult mouse dorsal root ganglia explants." J Neurosci Res 74(5): 726-35.
 Adult ganglionic peripheral neurons have lost dependence on target-derived neurotrophin signaling for survival and regeneration after injury. To understand the mechanisms required to sustain such processes at maturity, we are studying neuronal survival and axonal outgrowth of adult mouse dorsal root ganglia (DRG) explants. We have here examined the role of phosphatidylinositol 3-kinase (PI3-K) activity. Both neuronal survival and axonal outgrowth of spontaneously growing preparations were decreased significantly by the PI3-K inhibitor LY294002 as was the increased outgrowth caused by nerve growth factor or glial cell line-derived factor. Inhibition of PI3-K activity promoted neuronal cell death to the same extent in the presence as in the absence of a growth factor, whereas inhibition of mitogen-activated protein kinase, MAPK, lacked effect. Using a compartmentalized system, it could be shown that only axonal outgrowth was decreased when the outgrowth region only was exposed to LY294002. Already-formed growth cones showed morphological changes within 5-10 min after exposure to LY294002. Akt (PKB) is one downstream effector of PI3-K. Immunofluorescence revealed the presence of activated Akt in DRG cell bodies and in axonal growth cones. Immunoreactivity was decreased by PI3-K inhibition. The results suggest that Akt is constitutively active in adult DRG neurons, and that PI3-K mediated processes are involved in neuronal survival of one or more DRG neuronal subpopulations and also in axonal elongation. The possible significance of Akt signaling for these effects is discussed.

Efimov, I. R. (2003). "Fibrillation or neurillation: back to the future in our concepts of sudden cardiac death?" Circ Res 92(10): 1062-4.
 
Eguchi, Y., M. Ogiue-Ikeda, et al. (2003). "Control of orientation of rat Schwann cells using an 8-T static magnetic field." Neurosci Lett 351(2): 130-2.
 Schwann cells aid in neuronal regeneration in the peripheral nervous system via guiding the regrowth of axons. In this study, we investigated the magnetic orientation of Schwann cells, and of a mixture of Schwann cells and collagen, after an 8-tesla magnetic field exposure. We obtained cultured Schwann cells from dissected sciatic nerves of neonatal rats. After 60 h of magnetic field exposure, Schwann cells oriented parallel to the magnetic fields. In contrast, the mixture of Schwann cells and collagen, Schwann cells oriented in the direction perpendicular to the magnetic field after 2 h of magnetic field exposure. In this case, Schwann cells aligned along the collagen fiber oriented by magnetic fields. The magnetic control of Schwann cell alignment is useful in medical engineering applications such as nerve regeneration.

Ekstrom, P. A., U. Mayer, et al. (2003). "Involvement of alpha7beta1 integrin in the conditioning-lesion effect on sensory axon regeneration." Mol Cell Neurosci 22(3): 383-95.
 Conditioning lesions of peripheral nerves improve axonal regeneration after injury and involve changes in expression of proteins required for axonal growth. Integrin alpha7beta1 expression in motor and sensory neurons increases following nerve lesions and motor axon regeneration is impaired in alpha7 integrin KO mice (J. Neurosci. 20, 1822-1830). To investigate the role of alpha7beta1 integrin in sensory axon regeneration, dorsal root ganglia of adult mice were cultured in gels of laminin-rich extracellular matrix (Matrigel) or collagen. Normal dorsal root ganglia in Matrigel or collagen supplemented with laminin showed spontaneous axonal outgrowth, which was greatly increased in conditioned preparations, but only in the presence of laminin. Conditioned dorsal root ganglia from normal mice cultured with a blocking antibody to beta1 integrin and from alpha7 integrin KO mice showed reduced axonal growth in both Matrigel- and laminin-supplemented collagen gels. Enhanced axonal regeneration after conditioning lesions therefore involves increased responsiveness to laminin and integrin alpha7beta1 expression.

El-Gammal, T. A., A. El-Sayed, et al. (2003). "Surgical treatment of brachial plexus traction injuries in children, excluding obstetric palsy." Microsurgery 23(1): 14-7.
 Traumatic brachial plexus injuries in children, excluding birth palsy, are seldom reported. In this study, we report on 11 cases operated upon between 1995-1998, and followed for at least 30 months. All patients were males with an average age of 11 years (range, 3-16 years). The denervation time averaged 3.8 months (range, 1-8 months). Eight patients had two or more root avulsions; two had additional severe infraclavicular injuries. In total, 6 grafting and 25 extraplexal neurotization procedures were used. Donor nerves included the intercostal nerves, phrenic nerve, spinal accessory nerve, and contralateral C7 root. Elbow flexion was restored in all but 2 cases. Shoulder abduction varied from 30-90 degrees, according to the method of reconstruction. Triceps recovered in 2 cases and finger and wrist extensors in 1 case. Wrist and finger flexion was obtained in 1 case. Sensory recovery in the palm reached S2/S2+. Harvesting the phrenic nerve and the contralateral C7 root resulted in no residual morbidity. Compared to adults, children have a higher incidence of root avulsion, no deafferentiation pain, a higher incidence of associated skeletal injuries, and the same recovery rate of elbow and shoulder functions following plexus reconstruction, but recovery is faster. Given the frequency of root avulsions, neurotization is often required.

Ellezam, B., J. Bertrand, et al. (2003). "Vaccination stimulates retinal ganglion cell regeneration in the adult optic nerve." Neurobiol Dis 12(1): 1-10.
 We examined whether vaccination of adult rats with spinal cord homogenate (SCH) can promote regeneration of retinal ganglion cells (RGCs) after microcrush lesion of the optic nerve. Injured animals vaccinated with SCH showed axon growth into the optic nerve and such regeneration was not observed in animals vaccinated with liver homogenate (LH). Regeneration was not a consequence of neuroprotection since our vaccine did not protect RGCs from axotomy-induced cell death. Sera of vaccinated animals were tested for antibodies against myelin-associated glycoprotein, NogoA, Nogo-66 receptor, or chondroitin sulphate proteoglycans (CSPG), but no significant levels were detected. Antibodies to myelin basic protein were present in the serum of some SCH-vaccinated animals. In culture, serum from SCH-vaccinated animals promoted RGC growth on myelin but not on CSPG. Our results show that the effect of the pro-regenerative vaccine is mediated by antibodies to SCH. However, we were not able to detect a significant immune reaction to growth inhibitory proteins, suggesting alternative mechanisms for the success of vaccination to promote regeneration.

Ellis, R. A., M. J. Brenner, et al. (2003). "Use of mixed lymphocyte reaction to identify subimmunosuppressive FK-506 levels in mice." Microsurgery 23(3): 276-82.
 The immunosuppressive agent FK-506 has a well-described neuroregenerative effect that is mediated by a mechanism independent of calcineurin inhibition. FK-506 levels that fall below the threshold for immunosuppression could therefore potentially enhance nerve regeneration while minimizing toxicity. The purpose of this study was to characterize the dose-dependent effects of FK506 on T-cell proliferation, and establish a subimmunosuppressive dosing regimen for FK-506 in mice. Forty BALB/cJ mice were randomized to four groups corresponding to 0, 0.25, 0.5, or 1.0 mg/kg/day doses of FK-506. Ten days postoperatively, animals were sacrificed, and mixed lymphocyte reaction assays were performed to quantify the immune response to nerve allografts. Mice receiving 0.25 and 0.5 mg/kg/day of FK-506 exhibited a robust T-cell proliferation response, with stimulation indices approaching those of untreated animals. Mice treated with 1.0 mg/kg/day of FK-506 demonstrated significantly decreased T-cell proliferation. These results establish 0.5 mg/kg/day as an upper limit for subimmunosuppressive FK-506 administration.

Elmas, C., D. Erdogan, et al. (2003). "Expression of growth factors in fetal human olfactory mucosa during development." Growth Dev Aging 67(1): 11-25.
 The olfactory epithelium is one of the unique sites in the mammalian nervous system at which there is continual neurogenesis. Constant turnover of primary sensory neurons in the periphery results in remodeling of neuronal circuits and synapses in the olfactory bulb throughout life. Most of the specific mechanisms and factors that control this process are still unknown. Recent studies suggest that growth factors and their receptors may play a significant role in the development and continuous regeneration of olfactory neurons. In this study, standard immunohistochemical methods were used to detect the presence of epidermal growth factor-receptor, transforming growth factor-alpha and nerve growth factor-beta in the human olfactory epithelium of different developmental stages (7 to 30 weeks) in formalin-fixed tissue specimens. Immunoreactivity to epidermal growth factor-receptor was seen in basal cells, supporting cells, neurons, apical cytoplasmic region of olfactory epithelium, lamina propria and gland's cell cytoplasm. Similarly transforming growth factor-alpha immunoreactivity was recognized in basal cells, supporting cells, apical cytoplasmic region of olfactory epithelium, lamina propria and gland's cell cytoplasm but not in neurons. Nerve growth factor-beta detection was restricted on olfactory nerve cells, dentritic knob and basal cell layer. So, this study confirms the development of human olfactory mucosa and shows epidermal growth factor-receptor, transforming growth factor-alpha and nerve growth factor-beta proteins are reliable markers for developing olfactory epithelium.

Emerick, A. J., E. J. Neafsey, et al. (2003). "Functional reorganization of the motor cortex in adult rats after cortical lesion and treatment with monoclonal antibody IN-1." J Neurosci 23(12): 4826-30.
 We previously reported anatomical plasticity in the adult motor cortex after a unilateral sensorimotor cortex (SMC) lesion and treatment with monoclonal antibody (mAb) IN-1, which permits neurite outgrowth from the intact, opposite cortex into deafferented subcortical targets. This study was designed to investigate whether treatment with the mAb IN-1 after SMC lesion in the adult leads to functional reorganization of the intact, opposite motor cortex. Adult rats underwent unilateral SMC aspiration lesion and treatment with either mAb IN-1 or control antibody, or no treatment. After a 6 week survival period, the intact, opposite forelimb motor cortex was explored using intracortical microstimulation to evoke forelimb movements. A dramatic increase in ipsilateral movements of the lesion-impaired forelimb was found in animals treated with mAb IN-1 compared with control animals. These results resembled our previous findings of cortical reorganization in the spared hemisphere after neonatal cortical lesion and without any additional treatment. These results show that, after adult cortical lesion, treatment with mAb IN-1 induces a functional reorganization of the intact, opposite motor cortex.

Emanueli, C., P. Schratzberger, et al. (2003). "Paracrine control of vascularization and neurogenesis by neurotrophins." Br J Pharmacol 140(4): 614-9.
 The neuronal system plays a fundamental role in the maturation of primitive embryonic vascular network by providing a paracrine template for blood vessel branching and arterial differentiation. Furthermore, postnatal vascular and neural regeneration cooperate in the healing of damaged tissue. Neurogenesis continues in adulthood although confined to specific brain regions. Following ischaemic insult, neural staminal cells contribute towards the healing process through the stimulation of neurogenesis and vasculogenesis. Evidence indicates that nerves and blood vessels exert a reciprocal control of their own growth by paracrine mechanisms. For instance, guidance factors, including vascular endothelial growth factor A (VEGF-A) and semaphorins, which share the ability of binding neuropilin receptors, play a pivotal role in the tridimensional growth pattern of arterial vessels and nerves. Animal models and clinical studies have demonstrated a role of VEGF-A in the pathogenesis of ischaemic and diabetic neuropathies. Further, supplementation with VEGF-A ameliorates neuronal recovery by exerting protective effects on nerves and stimulating reparative neovascularization. Human tissue kallikrein, a recently discovered angiogenic and arteriogenic factor, accelerates neuronal recovery by stimulating the growth of vasa nervorum. Conversely, the neurotrophin nerve growth factor, known to regulate neuronal survival and differentiation, is now regarded as a stimulator of angiogenesis and arteriogenesis. These results indicate that angiogenesis and neurogenesis are paracrinally regulated by growth factors released by endothelial cells and neurons. Supplementation of these growth factors, alone or in combination, could benefit the treatment of ischaemic diseases and neuropathies.

Emes, R. D., W. Z. Wang, et al. (2003). "HmCRIP, a cysteine-rich intestinal protein, is expressed by an identified regenerating nerve cell." FEBS Lett 533(1-3): 124-8.
 A Hirudo medicinalis cDNA isolated from regenerating CNS tissue at 24 h post-axotomy was identified as a leech homologue of the mammalian cysteine-rich intestinal proteins (CRIPs) and named HmCRIP. HmCRIP is up-regulated within 6 h of axotomy, peaking at 24 h. This is the first demonstration of a CRIP homologue in regenerating CNS and in a serotonergic neurone. In rodents CRIP is an important factor in the regulation of the inflammatory immune response through control of Th1/Th2 differentiation. The role of HmCRIP in the regeneration competent environment of the annelid central nervous system is discussed.

Erie, J. C., S. V. Patel, et al. (2003). "Aberrant corneal nerve regeneration after PRK." Cornea 22(7): 684-6.
 PURPOSE: To report a case of aberrant corneal nerve regeneration after myopic photorefractive keratectomy (PRK). METHODS: One patient underwent bilateral PRK to correct a refractive error of -5.50 D in each eye. Thirteen months after the original PRK, the left eye underwent an uncomplicated PRK reoperation to correct a regression of -1.00 D. The central corneas were examined by confocal microscopy preoperatively in both eyes, at 1 and 2 years after the original PRK in the right eye, and before and 1 and 2 years after the PRK reoperation in the left eye. RESULTS: Aberrant anterior stromal nerves with a coiled course and irregular branching pattern were identified 22 micro m deep to the most anterior keratocyte layer at 1 year after the PRK reoperation in the left eye and remained unchanged 2 years after reoperation. No abnormal stromal nerves were identified in the left eye before the reoperation or at any time in the right eye. CONCLUSION: Aberrant regeneration of corneal stromal nerves may occur after myopic PRK reoperation.

Evans, G. R. and K. Brandt (2003). "Peripheral nerve regeneration: the effects of postoperative irradiation." Plast Reconstr Surg 111(6): 2023-4.
 
Evers, B. M., I. L. Weissman, et al. (2003). "Stem cells in clinical practice." J Am Coll Surg 197(3): 458-78.
 
Eyupoglu, I. Y., I. Bechmann, et al. (2003). "Modification of microglia function protects from lesion-induced neuronal alterations and promotes sprouting in the hippocampus." Faseb J 17(9): 1110-1.
 Primary neuronal destruction in the central nervous system triggers rapid changes in glial morphology and function, after which activated glial cells contribute to secondary neuronal changes. Here we show that, after entorhinal cortex lesion, activation of microglia, but not other glial cells, leads to massive secondary dendritic changes of deafferentiated hippocampal neurons. Blocking of microglial activation in vivo reduced this secondary neuronal damage and enhanced regenerative axonal sprouting. In contrast, abolishing astrocytes or oligodendroglia did not result in specific neuronal changes. Furthermore, primary damage leads to an interleukin 1beta up-regulation, which is attenuated by the immuno-modulator transforming growth factor beta1, whereas tumor necrosis factor alpha is not affected. Modification of microglial activity following denervation of the hippocampus protects neurons from secondary dendritic alterations and therefore enables their reinnervation. These data render activated microglia a putative therapeutic target during the course of axonal degeneration.

Faivre, S., A. Lim, et al. (2003). "Adjacent and spontaneous neurotization after distal digital replantation in children." Plast Reconstr Surg 111(1): 159-65; discussion 166.
 In an exclusively pediatric population, this retrospective study examined the functional and aesthetic results after distal replantation without nerve suture. The aim was to demonstrate, in the child, the presence of spontaneous nervous regeneration resulting in a fingertip pulp with discriminatory sensation. Eight amputations in eight children with a mean age of 9 years and 2 months on the day of the accident were reviewed. The cases were managed by a single surgeon over a period of 8 years and were collected from two different hand centers. The patients were then examined by a different surgeon, and the data were collected. Sensibility was evaluated using the Weber, Semmes-Weinstein, and wrinkle tests. The results were excellent, with mean values of 4.6 mm for the Weber test, 3.3 for the Semmes-Weinstein test, and a positive wrinkle test in all subjects. All patients thus recovered discriminatory sensation with minimal aesthetic sequelae. The usual factors adversely affecting the results of the replantation (ischemic time, level and mechanism of the amputation, and quality of the venous return) were examined, but no statistical analysis was performed because of the small sample size. This study demonstrates the presence of the clinical phenomenon of adjacent neurotization in the absence of nerve repair. It thus confirms that children are excellent candidates for replantation of the distal extremities, even when nerve suture is not performed.

Fansa, H. and G. Keilhoff (2003). "[Factors influencing nerve regeneration]." Handchir Mikrochir Plast Chir 35(2): 72-82.
 This paper describes the most important cellular and molecular factors that influence nerve regeneration. The first prerequisite for axonal regeneration is survival of the neuron. This depends on neuron type, age, and the degree and proximity of the injury to the cell body. Spinal motoneurons are less susceptible to injury-induced death than cranial motoneurons and sensory neurons. The surviving neurons undergo changes characteristic of a switch from a transmitting mode to a growing mode. They produce various neurotrophic factors and their receptors influencing the neuron and the non-neuronal cells such as Schwann cells. The distal nerve stump undergoes degenerative processes including removal of axons and phagocytosis of myelin debris, the so-called Wallerian degeneration. Until the second day phagocytosis is done by Schwann cells, hematogenous macrophages invade the distal stump at the second day and phagocyte the whole debris within two weeks. Devoid of axonal contact, the myelinating Schwann cells switch their function from myelination to growth support for the regenerating axons, including cell proliferation, downregulation of myelin components and upregulation of neurotrophic factors. Additionally, the Schwann cells form the so-called Bands of Bungner, cell columns serving as pathway for the growing axon. Trophic factors, cell adhesion molecules and extracellular matrix influence the neuron, the growing axon and the endorgan as well as the non-neuronal cells such as Schwann cells, fibroblasts and macrophages. Application of drugs or trophic substances to enhance nerve regeneration after trauma and reconstruction is in the very beginning, and thus requires further experimental and clinical studies. Experimentally, FK 506 was found to support axonal regeneration after crush lesions and nerve grafting. Growth factors are currently administered clinically in other neurological diseases.

Fansa, H., T. Dodic, et al. (2003). "Tissue engineering of peripheral nerves: Epineurial grafts with application of cultured Schwann cells." Microsurgery 23(1): 72-7.
 After a simple nerve lesion, primary microsurgical suture is the treatment of choice. A nerve gap has to be bridged, with a nerve graft sacrificing a functioning nerve. Alternatively, tissue engineering of nerve grafts has become a subject of experimental research. It is evident that nerve regeneration requires not only an autologous, allogenous, or biodegradable scaffold, but additional interactions with regeneration-promoting Schwann cells. In this study, we compared epineurial and acellularized epineurial tubes with and without application of cultured Schwann cells as alternative grafts in a rat sciatic nerve model. Autologous nerve grafts served as controls. Evaluation was performed after 6 weeks; afterwards, sections of the graft and distal nerve were harvested for histological and morphometrical analysis. Compared to controls, all groups showed a significantly lower number of axons, less well-shaped remyelinizated axons, and a delay in clinical recovery (e.g., toe spread). The presented technique with application of Schwann cells into epineurial tubes did not offer any major advantages for nerve regeneration. Thus, in this applied model, neither the implantation of untreated nor the implantation of acellularized epineurial tubes with cultured Schwann cells to bridge nerve defects was capable of presenting a serious alternative to the present gold standard of conventional nerve grafts for bridging nerve defects in this model.

Farhadieh, R. D., S. Nicklin, et al. (2003). "The role of nerve growth factor and brain-derived neurotrophic factor in inferior alveolar nerve regeneration in distraction osteogenesis." J Craniofac Surg 14(6): 859-65.
 SUMMARY: Distraction osteogenesis (DO) has become the mainstay of treatment of mandibular hypoplasias. Despite the clinical acceptance of the technique in the last decade, little is known of the biological mechanism of bone and soft tissue regeneration. The biological response of peripheral nerves to distraction has not been well documented. This study examined the role of two neurotrophic molecules, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), in DO on nerve regeneration of the inferior alveolar nerve (IAN) in an ovine mandible model. Twelve animals were randomly divided into three groups and distracted at 5, 10, and 15 days using a mandibular osteotomy and uniaxial external distractor. The mental nerves and the IAN from the distracted site were harvested at the end of the distraction period and examined for the presence of NGF and BDNF using immunohistochemistry. Nerve growth factor expression was increased at both sites, whereas BDNF was only expressed at the mental nerve on the distracted side. Nerve growth factor and BDNF are involved in the response of the peripheral nerves to injury. Mechanical force applied to the IAN by distraction may lead to detachment of Schwann cells from their axons, leading to segmental degeneration. The resulting myelin sheath debris may serve as a trigger for higher expression of NGF and BDNF, facilitating Schwann cell proliferation and remyelination of the affected segment. Distraction of the mandible may serve as a source of subacute injury to the IAN and influence NGF and BDNF.

Fernandez, E., F. Di Rocco, et al. (2003). "Reinnervation of extraocular muscles by facial-to-oculomotor nerve anastomosis in rats: anatomic nuclear changes." Neurosurgery 53(2): 409-14; discussion 414-5.
 OBJECTIVE: Oculomotor nerve palsy greatly impairs the patient's daily life. After oculomotor nerve injury, when the central nerve stump is not available, neurotization of the distal nerve stump with a donor nerve may be performed. Here, we present an experimental anatomic study in rats related to the motor nuclear organization after facial-to-oculomotor nerve anastomosis. METHODS: In adult rats, the right oculomotor nerve was transected at the skull base. Then, the ipsilateral facial nerve was exposed at the stylomastoid foramen and connected side-to-end to one extremity of a peroneal nerve autograft. The other extremity of the nerve autograft was connected end-to-end to the distal stump of the transected oculomotor nerve. Twelve weeks later, axonal regeneration in the autograft and brainstem somatotopic representation of the reinnervated extraocular muscles were investigated by use of histological and retrograde axonal tracing techniques. RESULTS: The autograft was reinnervated by a large number of small axons, 1 to 5 microm in diameter. After tracer injection into the superior rectus and medial rectus muscles, retrogradely labeled neurons were seen not only in the ipsilateral facial nucleus (16%) but also in the contralateral nucleus (8%). Labeled neurons were also seen in the ipsilateral abducens (12%), motor trigeminus (7%), trochlear (23%), and contralateral trochlear (34%) nuclei. In normal rats, the extraocular muscles are innervated by unilateral-ipsilateral brainstem motor nuclei, except for the superior rectus and superior oblique muscles, which are innervated by bilateral, primarily contralateral, nuclei. CONCLUSION: The central rearrangement of the extraocular muscle nuclei after facial-to-oculomotor nerve anastomosis represents an original example of plasticity. Functional studies are needed to demonstrate whether this procedure might serve to restore some degree of eye motility.

Fernandez-Espejo, E., F. El Banoua, et al. (2003). "[Natural "dopaminotrophic" cell transplant: a new concept in antiparkinsonian therapy]." Rev Neurol 36(6): 540-4.
 AIM AND METHOD: Parkinson s disease is caused by the degeneration of dopaminergic neurons of substantia nigra projecting to striatum. Cellular substitution represents a potentially treatment once beneficial levodopa effects wear off. A promising therapeutic approach is grafting cells or other vectors which release neuroprotective molecules that stimulate regeneration in the damaged nigrostriatal system or, in other words, that exert a dopaminotrophic action. We have tested the suitability of intrastriatal grafts of extra adrenal chromaffin cells taken from the Zuckerkandl s organ. This paraganglion contains chromaffin cells that express and release glial cell line derived neurotrophic factor (GDNF) and transforming growth factor b1 (TGF b1), both known to protect dopamine cells in vitro and in vivo. Grafts induced a functional recovery of parkinsonian rats which developed over months. The beneficial effects of grafts of the Zuckerkandl s organ were related to long survival of grafted cells, striatal reinnervation, enhancement of dopamine levels in the host striatum, and the cell delivery into the host striatum of GDNF and TGF b1. CONCLUSION: Our result should stimulate research on the clinical applicability of transplants of the Zuckerkandl s organ in Parkinson s disease

Ferraresi, S., D. Garozzo, et al. (2003). "Common peroneal nerve injuries: results with one-stage nerve repair and tendon transfer." Neurosurg Rev 26(3): 175-9.
 The authors report their experience in the treatment of common peroneal nerve (CPN) injuries using a one-stage procedure of nerve repair and tibialis posterior tendon transfer. A series of 45 patients with traumatic injury and graft repair of the CPN is presented. From 1988 to 1991, the six patients elected for surgery had only nerve repair: five ultimately did not recover, while muscle contraction in the remaining patient was graded M1-2. Since 1991, nerve surgery in our clinic was associated with tendon transfer procedures (39 cases) which were followed by a satisfactory reinnervation rate. Nerve transection and iatrogenic injuries, torsion/dislocation of the knee, complex biosseous fractures of the leg, and gunshot wounds showed excellent to fair results in decreasing order: in nerve sections, muscle recovery scored M3 or M4+ in all the patients, and in nerve ruptures due to severe dislocation of the knee, it was M3 or M4+ in 85% of cases. The association of microsurgical nerve repair and tendon transfer has changed the course of CPN injuries.

Ferretti, A., E. Boschi, et al. (2003). "Angiogenesis and nerve regeneration in a model of human skin equivalent transplant." Life Sci 73(15): 1985-94.
 The angiogenesis and reinnervation were studied in a porcine model of human skin equivalent (SE) graft and the relationship between the two processes was investigated. Confocal laser scanning microscopy was used to monitor, during the healing process, the pattern of vascularization and reinnervation at different time points. The SE was obtained by co-culturing fibroblasts and keratinocytes on a collagen-glycosaminoglycan-chitosan biopolymer and grafted on dorsal wounds generated by full-thickness resection in 25/30 Kg Large white pigs. Frozen sections were obtained from biopsies performed in autograft and xenograft, then were immunolabeled by using the endothelial marker lectin Lactifolia and with the neuronal marker gene product PGP9.5. Cajal staining was also used to visualize the nerve fibers. The results show that the vascularization precedes the innervation process. These data are consistent with the view that the development of nervous tissue is driven by nutritional and trophic factors provided by the vascular system. The arborization of the two systems observed during the third week from the graft might play a key role in maintaining the healing process and the graft survival.

Ferretti, P., F. Zhang, et al. (2003). "Changes in spinal cord regenerative ability through phylogenesis and development: lessons to be learnt." Dev Dyn 226(2): 245-56.
 Lower vertebrates, such as fish and amphibians, and developing higher vertebrates can regenerate complex body structures, including significant portions of their central nervous system. It is still poorly understood why this potential is lost with evolution and development and becomes very limited in adult mammals. In this review, we will discuss the current knowledge on the cellular and molecular changes after spinal cord injury in adult tailed amphibians, where regeneration does take place, and in developing chick and mammalian embryos at different developmental stages. We will focus on the recruitment of progenitor cells to repair the damage and discuss possible roles of changes in early response to injury, such as cell death by apoptosis, and of myelin-associated proteins, such as Nogo, in the transition between regeneration-competent and regeneration-incompetent stages of development. A better understanding of the mechanisms underlying spontaneous regeneration of the spinal cord in vivo in amphibians and in the chick embryo will help to devise strategies for restoring function to damaged or diseased nervous tissues in mammals.

Filbin, M. T. (2003). "Myelin-associated inhibitors of axonal regeneration in the adult mammalian CNS." Nat Rev Neurosci 4(9): 703-13.
 
Fink, D. J., J. Glorioso, et al. (2003). "Therapeutic gene transfer with herpes-based vectors: studies in Parkinson's disease and motor nerve regeneration." Exp Neurol 184 Suppl 1: S19-24.
 We have examined the possibility of using herpes simplex virus (HSV)-based vectors to prevent neuronal cell death and enhance functional recovery after injury. In the 6-hydroxydopamine (6-OHDA) model of Parkinson's disease (PD) and after proximal spinal root injury, direct stereotactic injection of HSV-based vectors constructed to express the glial cell derived neurotrophic factor (GDNF) or the anti-apoptotic peptide Bcl-2 prevented neuronal death and enhanced recovery. Gene transfer may be useful in the treatment of neurologic disorders in which neuronal cell death occurs in a restricted anatomic distribution.

Fishman, H. M. and G. D. Bittner (2003). "Vesicle-mediated restoration of a plasmalemmal barrier in severed axons." News Physiol Sci 18: 115-8.
 Ca(2+)-induced endocytotic vesicles undergo protein-mediated interactions to restore a selectively permeable barrier and propagated action potentials in severed invertebrate giant axons. Similar barrier-restoration phenomena observed in cultured mammalian cells with transected neurites suggest that cellular/molecular mechanisms that repair plasmalemmal damage are phylogenetically conserved.

Flynn, L., P. D. Dalton, et al. (2003). "Fiber templating of poly(2-hydroxyethyl methacrylate) for neural tissue engineering." Biomaterials 24(23): 4265-72.
 We have developed a method to create longitudinally oriented channels within poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogels for neural tissue engineering applications. Incorporated into an entubulation strategy, these scaffolds have the potential to enhance nerve regeneration after transection injuries of either the spinal cord or the peripheral nerve by increasing the available surface area and providing guidance to extending axons and invading cells. The fabrication process is straightforward and the resultant scaffolds are highly reproducible. Polycaprolactone (PCL) fibers were extruded and embedded in transparent, crosslinked pHEMA gels. Sonication of the pHEMA/PCL composite in acetone resulted in the complete dissolution of the PCL, leaving longitudinally oriented, fiber-free channels in the pHEMA gel. Regulating the size and quantity of the PCL fibers allowed us to control the diameter and number of channels. Small and large channel scaffolds were fabricated and thoroughly characterized. The small channel scaffolds had 142+/-7 channels, with approximately 75% of the channels in the 100-200 micro m size range. The large channel scaffolds had 37+/-1 channels, with approximately 77% of the channels in the 300-400 micro m range. The equilibrium water content (EWC), porosity and compressive modulus were measured for each of the structures. Small and large channel scaffolds had, respectively, EWCs of 55.0+/-1.2% and 56.2+/-2.9%, porosities of 35+/-1% and 40+/-1% and compressive moduli of 191+/-7 and 182+/-4kPa.

Fournier, A. E., B. T. Takizawa, et al. (2003). "Rho kinase inhibition enhances axonal regeneration in the injured CNS." J Neurosci 23(4): 1416-23.
 Myelin-associated inhibitors limit axonal regeneration in the injured brain and spinal cord. A common target of many neurite outgrowth inhibitors is the Rho family of small GTPases. Activation of Rho and a downstream effector of Rho, p160ROCK, inhibits neurite outgrowth. Here, we demonstrate that Rho is directly activated by the myelin-associated inhibitor Nogo-66. Using a binding assay to measure Rho activity, we detected increased levels of GTP Rho in PC12 and dorsal root ganglion (DRG) cell lysates after Nogo-66 stimulation. Rho activity levels were not affected by Amino-Nogo stimulation. Rho inactivation with C3 transferase promotes neurite outgrowth of chick DRG neurons in vitro, but with the delivery method used here, it fails to promote neurite outgrowth after corticospinal tract (CST) lesions in the adult rat. Inhibition of p160ROCK with Y-27632 also promotes neurite outgrowth on myelin-associated inhibitors in vitro. Furthermore, Y-27632 enhances sprouting of CST fibers in vivo and accelerates locomotor recovery after CST lesions in adult rats.

Francel, P. C., K. S. Smith, et al. (2003). "Regeneration of rat sciatic nerve across a LactoSorb bioresorbable conduit with interposed short-segment nerve grafts." J Neurosurg 99(3): 549-54.
 OBJECT: This study was conducted to evaluate peripheral nerve regeneration through a conduit composed of a bioresorbable material (LactoSorb). METHODS: Sprague-Dawley rats weighing approximately 250 g were randomized into five groups. A 20-mm-long sciatic nerve gap was created, then it was bridged by a reverse nerve autograft (Group I), an empty silicone tube (Group II), a silicone tube containing a short (2-mm) interposed nerve segment (Group III), an empty LactoSorb conduit (Group IV), or a LactoSorb conduit containing a 2-mm interposed nerve segment (Group V). The intact sciatic nerve served as the control in each animal. At 16 weeks postoperatively, no nerve regeneration was observed through either the empty silicone tube or the empty LactoSorb conduit. There was regeneration in all animals receiving the reverse autograft as well as in all animals receiving the silicone or LactoSorb conduit containing the 2-mm interposed nerve segment. Effective regeneration was assessed based on histological, electrophysiological, and morphometric criteria. CONCLUSIONS: The results indicate that a conduit made of resorbable material will support sciatic nerve regeneration over a critical gap defect.

Fressinaud, C., I. Jean, et al. (2003). "Selective decrease in axonal nerve growth factor and insulin-like growth factor I immunoreactivity in axonopathies of unknown etiology." Acta Neuropathol (Berl) 105(5): 477-83.
 In an attempt to approach the mechanisms underlying axonopathies of unknown etiology, we have studied by immunocytochemistry the fate of several growth factors in eight of such cases that we had previously analyzed by morphometry and which were characterized by a decrease in neurofilaments and an increase in beta tubulin immunostaining. Here we establish that, contrary to beta tubulin, growth-associated protein43 (GAP-43) immunolabeling is not up-regulated in theses cases, correlating well with the failure of regeneration. Neurotrophin-3 (NT-3) and its receptor TrkC were not modified compared to controls (five cases). On the contrary, we observed in all cases a pronounced decrease in the number of fibers labeled for nerve growth factor (NGF) and insulin-like growth factor I (IGF-I), which were both approximately half of control values. This decrease could not be ascribed to the reduction in fiber density since it was also present in cases without fiber loss (isolated large fiber atrophy). The fact that only around 50% of fibers were stained, versus all fibers in controls, probably accounted for this decrease. It contrasted also with the normality of NGF and IGF-I immunolabeling in six cases of chronic inflammatory demyelinating neuropathy that were investigated in parallel. These results differ from those reported in experimental diabetic neuropathy, during which NT-3 is also decreased. A deficient supply of specific growth factors delivered by neuronal targets may be responsible for these neuropathies and their associated axonal cytoskeleton abnormalities.

Friedman, S. M. (2003). "Optociliary venous anastomosis after radial optic neurotomy for central retinal vein occlusion." Ophthalmic Surg Lasers Imaging 34(4): 315-7.
 Radial optic neurotomy has been shown to be beneficial for the treatment of central retinal vein occlusion. Two patients developed optociliary venous anastomosis after radial optic neurotomy for central retinal vein occlusion with improvement in vision and clinical appearance. Optociliary venous anastomosis may portend a favorable prognosis.

Frost, E. E., J. A. Nielsen, et al. (2003). "PDGF and FGF2 regulate oligodendrocyte progenitor responses to demyelination." J Neurobiol 54(3): 457-72.
 Acute demyelination of adult CNS, resulting from trauma or disease, is initially followed by remyelination. However, chronic lesions with subsequent functional impairment result from eventual failure of the remyelination process, as seen in multiple sclerosis. Studies using animal models of successful remyelination delineate a progression of events facilitating remyelination. A universal feature of this repair process is extensive proliferation of oligodendrocyte progenitor cells (OPs) in response to demyelination. To investigate signals that regulate OP proliferation in response to demyelination we used murine hepatitis virus-A59 (MHV-A59) infection of adult mice to induce focal demyelination throughout the spinal cord followed by spontaneous remyelination. We cultured glial cells directly from demyelinating and remyelinating spinal cords using conditions that maintain the dramatically enhanced OP proliferative response prior to CNS remyelination. We identify PDGF and FGF2 as significant mitogens regulating this proliferative response. Furthermore, we demonstrate endogenous PDGF and FGF2 activity in these glial cultures isolated from demyelinated CNS tissue. These findings correlate well with our previous demonstration of increased in vivo expression of PDGF and FGF2 ligand and corresponding receptors in MHV-A59 lesions. Together these studies support the potential of these pathways to function in vivo as critical factors in regulating remyelination.

Fujii, N., H. Ohnishi, et al. (2003). "Regeneration of nerve fibres in the peri-implant epithelium incident to implantation in the rat maxilla as demonstrated by immunocytochemistry for protein gene product 9.5 (PGP9.5) and calcitonin gene-related peptide (CGRP)." Clin Oral Implants Res 14(2): 240-7.
 The response of nerve fibres in the peri-implant epithelium to titanium implantation was investigated with an experimental model using rat maxilla and immunohistochemical techniques. The latter employed antibodies to protein gene product 9.5 (PGP9.5), and to calcitonin gene-related peptide (CGRP). In control rats without an implantation, a dense innervation of PGP9.5- and CGRP-positive nerve fibres was recognized throughout the junctional epithelium, as has been previously reported. A titanium-implantation induced a remarkable inflammatory reaction, as well as the destruction of covering epithelial cells. By 3-5 days post-implantation, inflammatory reaction showed a tendency to disappear, and the peri-implant epithelium showed proliferation and down-growth along the implant. At this stage, no nerve fibres were found around the peri-implant epithelium. At 10 days, a few nerve fibres reached the basal cell layers of the peri-implant epithelium, and entered it 15 days after implantation when the peri-implant epithelial cells showed morphological features roughly resembling those of normal junctional epithelial cells. At the complete osseointegration stage (days 20-30), the PGP9.5- and CGRP-positive nerve fibres, thin and beaded in appearance, were found distributed in the peri-implant epithelium. After 20 days, the numerical density of the intraepithelial nerves in the peri-implant epithelium appeared the same as, or less than, that in the normal junctional epithelium. These findings indicate that the peri-implant epithelium shows the same innervation as that in normal junctional epithelium, and that the intraepithelial nerve fibres in the peri-implant epithelium might have diverse functions, which have been suggested in the literature.

Fukaya, K., M. Hasegawa, et al. (2003). "Oxidized galectin-1 stimulates the migration of Schwann cells from both proximal and distal stumps of transected nerves and promotes axonal regeneration after peripheral nerve injury." J Neuropathol Exp Neurol 62(2): 162-72.
 Oxidized galectin-1 has recently been identified as a key factor that plays important roles in initial axonal growth in injured peripheral nerves. The aim of this study was to investigate the effects of oxidized galectin-1 on regeneration of rat spinal nerves using acellular autografts (containing no viable cells) and allografts (containing no cell membranes) with special attention to the relationship between axonal regeneration and Schwann cell migration. Immunohistochemically, endogenous galectin-1 was expressed in dorsal root ganglion (DRG) neurons, spinal cord motoneurons, and axons and Schwann cells in normal sciatic nerves. Administration of oxidized recombinant human galectin-1 (rh-gal-lox, 5 ng/ml) in autograft model promoted axonal regeneration from motoneurons as well as from DRG neurons; this was confirmed by a fluorogold tracer study (p < 0.05). Anti-rh-gal-1 antibody (30 microg/ml) strongly inhibited axonal regrowth (p < 0.05). Pretreatment of allografts with rh-gal-lox stimulated the migration of Schwann cells not only from proximal stumps but also from distal stumps into the grafts, resulting in accelerated axonal regeneration (p < 0.05). Moreover, Schwann cell migration preceded the axonal growth in the presence of exogenous rh-gal-lox in the grafts. These results strongly suggest that local administration of exogenous rh-gal-lox promotes the migration of Schwann cells followed by axonal regeneration from both motor and sensory neurons, resulting in acceleration of neuronal repair. This technique may also be of value in the repair of human nerves.

Fulton, I. C., J. A. Stick, et al. (2003). "Laryngeal reinnervation in the horse." Vet Clin North Am Equine Pract 19(1): 189-208, viii.
 Left laryngeal hemiplegia is a frustrating condition for the equine athlete and equine veterinarian. Treatment for the past 30 years has centered on the prosthetic laryngoplasty ("tie-back") with or without ventriculectomy. Laryngeal reinnervation has been used successfully in people and has been shown experimentally to benefit affected horses. This article reviews equine laryngeal reinnervation using the nerve muscle pedicle graft and describes the surgical technique, its complications, and the follow-up in 146 cases treated over the past 10 years. Also discussed is ongoing research into stimulation studies to improve the success of equine laryngeal reinnervation.

Furukawa, K. and M. Nishio (2003). "[Function of gangliosides]." Tanpakushitsu Kakusan Koso 48(8 Suppl): 952-7.
 
Furukawa, Y., N. Hashimoto, et al. (2003). "Down-regulation of an ankyrin repeat-containing protein, V-1, during skeletal muscle differentiation and its re-expression in the regenerative process of muscular dystrophy." Neuromuscul Disord 13(1): 32-41.
 Using Western blot analysis and immunohistochemical methods, we examined the expression of V-1, a member of the ankyrin repeat-containing protein family, during differentiation and regeneration of skeletal muscle. The expression of V-1 was high in cultured myoblasts and decreased during their differentiation into myotubes, while high expression was maintained when muscle differentiation was inhibited by treatment with basic fibroblast growth factor. Down-regulation of V-1 also occurred during in vivo muscle differentiation from embryonic to postnatal stages, reaching an undetectable level in mature skeletal muscle. In contrast, strong V-1 immunoreactivity was detected again in myoblasts and regenerating muscle fibers with a small diameter, which were observed in Duchenne muscular dystrophy and its animal model, mdx mouse. Thus, it seems that V-1 is a good marker for early stage of muscle regeneration and changes of its expression suggest that V-1 plays a role in prenatal muscle differentiation and postnatal muscle regeneration.

Gage, F. H. (2003). "Brain, repair yourself." Sci Am 289(3): 46-53.
 
Gamez, E., K. Ikezaki, et al. (2003). "Photoconstructs of nerve guidance prosthesis using photoreactive gelatin as a scaffold." Cell Transplant 12(5): 481-90.
 We devised a novel nerve prosthesis composed of an elastomeric gelatinous tube and multifilament gelatinous fibers, both of which were prepared from styrene-derivatized gelatin, which allows in situ formation of a bioactive substance-incorporated gel. An in vitro study showed that the axonal regeneration potential of a photocured gelatin layer impregnated with laminin, fibronectin, and NGF was almost comparable with that of coated Matrigel. A nerve conduit and fibers prepared from photoreactive gelatin was subjected to visible-light irradiation with rotation in the presence of camphorquinone as a photoinitiator using a custom-designed apparatus. A sample of transparent gelatinous conduit with an inner diameter of 1.2 mm and a wall thickness of 0.6 mm and gelatin fibers ranging from 10 to 100 pm in diameter were produced. The photocured elastomeric gelatinous tube was flexible and had structural integrity that allowed mechanical handling without breaking. A novel nerve guidance prosthesis composed of tubes packed with fibers was assembled. This photofabrication technology may enable the design of a tailor-made shape and rapid morphogenesis and functional recovery of damaged nerve tissue.

Gao, M. T., D. M. Jiang, et al. (2003). "[Effect of subcutaneous implant of peripheral nerve allograft on sciatic nerve regeneration in rats]." Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 17(4): 312-4.
 OBJECTIVE: To study the effect of subcutaneous implant of peripheral nerve allograft on sciatic nerve regeneration in rats. METHODS: Out of 30 male Wistar rats, 6 were donors and 24 were divided randomly into 2 groups. In experimental group (group A, n = 12), a 15 mm segment of sciatic nerve harvested from donors was separately inserted into subcutaneous compartment on the right thigh; two weeks later, the segment of sciatic nerve in subcutaneous compartment was removed and transplanted into a 10 mm sciatic nerve defect of left, which was made immediately. In the control group (group B, n = 12), a 10 mm sciatic nerve defect was made and immediately repaired in situ on the left thigh. The regeneration of sciatic nerve was examined histologically (after 2, 4, 8, and 14 weeks) and electrophysiologically (after 14 weeks of operation). RESULTS: After 2 weeks of operation, the inflammatory reaction was a little stronger in group A than in group B. After 4 weeks, the intensity of the inflammatory reaction was similar between two groups; some collagen fibers proliferated. After 8 weeks, the inflammatory reaction ended and the collagen fibers proliferated obviously. After 14 weeks of operation, the structure of epineurium was in integrity and there was no obvious difference in perineurium and endonurium between two groups. A large number of myelinated nerve fibers and a small number of unmyelinated nerve fibers regenerated. The structure of myelin sheath was in integrity. The number and size of regenerated axon had no significant difference between two groups(P > 0.05). The conduction velocity, the peak value and the latent period of motor nerve were no significant difference between two groups (P > 0.05). CONCLUSION: The allograft of sciatic nerve inserted into subcutaneous compartment can promote nerve regeneration.

Garcia, M., V. Forster, et al. (2003). "In vivo expression of neurotrophins and neurotrophin receptors is conserved in adult porcine retina in vitro." Invest Ophthalmol Vis Sci 44(10): 4532-41.
 PURPOSE. To characterize and compare the expression of neurotrophins (NTs) and their receptors within adult porcine retinal ganglion cells (RGCs) in vivo and in vitro. METHODS. The distribution of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and -4 (NT-4), and their high-affinity receptors TrkA, TrkB, TrkC and low-affinity receptor p75, was analyzed in adult porcine retinal sections by immunohistochemistry. In addition, adult porcine retinas were dissociated and cultured in four different conditions: control, semipure RGCs, supplemented with BDNF, or seeded on Muller glia feeder layers. Double immunostaining was performed with antibodies to NTs or their receptors combined with neurofilament antibody to identify RGCs in culture. RESULTS. In vivo, immunolabeling of NGF was very faint, BDNF was especially prominent in RGCs and inner nuclear layer cells, NT-3 stained widespread nuclei, and NT-4 was undetectable. TrkA immunoreactivity was visible in the nerve fiber layer, TrkB staining was within RGC bodies, TrkC was undetectable, and p75 was widely expressed across the retina, within the Muller glia. Expression of neurotrophins and their receptors was maintained in all four models of adult RGCs in vitro, showing that expression was not influenced by substrate or culture conditions. We observed prominent staining of TrkA within growth cones, and a clear expression of p75 within a subpopulation of RGCs in vitro. CONCLUSIONS. These findings demonstrate that the expression of NTs and their receptors within adult porcine RGCs is maintained in vitro, under conditions of limited interaction with neighboring neurons and deprived of afferent inputs and target tissue. TrkA may be involved in regeneration of nerve terminals.

Garland, R., F. A. Frizelle, et al. (2003). "A retrospective audit of long-term lower limb complications following leg vein harvesting for coronary artery bypass grafting." Eur J Cardiothorac Surg 23(6): 950-5.
 OBJECTIVE: To evaluate the prevalence of leg complications following leg-vein harvest for coronary artery bypass grafting. METHOD: A questionnaire was sent to patients who had coronary artery bypass surgery between January 1993 and December 1998. Questions addressed pain, numbness, infection, swelling and general healing. The relationship between the risk factors of diabetes, peripheral vascular disease, previous fractures/injuries to legs, previous deep vein clots and arthritis affecting the legs with post operative symptoms of pain, numbness, swelling and general healing was explored with multivariate analysis. RESULTS: Of 700 questionnaires sent out 497 were returned, of which 422 (60%) were suitable for analysis. Numbness or tingling related to the wound was reported by 256 (61%), of whom 94 (37%) improved within 3 months. However, 105 (41%) had persistent numbness beyond 2 years. Pain in the wound was reported by 193 (46%), of whom 149 (77%) reported that this had improved by 3 months and only 19 (10%) had pain persisting beyond 2 years. A leg wound infection was reported by 126 (32%) patients, with 82 (65%) of these receiving antibiotics. A total of 336 (87% of 387 responses) described their wound as completely healed at 3 months. Unilateral leg swelling was reported by 175 (41%) with 98 of these (56% of those with swelling) improving by 3 months and 41 (23%) with swelling persisting beyond 2 years. There was no relation of wound problems to examined risk factors diabetes (P-values for numbness 0.31, wound healing 0.15, swelling 0.21, pain 0.22) and peripheral vascular disease (P-values for numbness 0.8, wound healing 0.21, swelling 0.18, pain 0.09). There was insufficient data to comment on the influence of fractures/injuries to legs, previous deep vein clots and arthritis affecting the legs. CONCLUSIONS: Wound complications are common following leg vein harvest. Prevalence of infection was higher than has previously been reported. Few people suffer long-term pain from saphenous nerve damage although paraesthesia and swelling were common long-term complications. We did not identify either diabetes or peripheral vascular disease as a risk factor for pain, numbness, swelling or problems with general healing. There is a need for a large multicentre prospective study.

Gatzinsky, K. P., B. Holtmann, et al. (2003). "Early onset of degenerative changes at nodes of Ranvier in alpha-motor axons of Cntf null (-/-) mutant mice." Glia 42(4): 340-9.
 The nodes of Ranvier are sites of specific interaction between Schwann cells and axons. Besides their crucial role in transmission of action potentials, the nodes of Ranvier and in particular the paranodal axon-Schwann cell networks (ASNs) are thought to function as local centers in large motor axons for removal, degradation, and disposal of organelles. In order to test whether ciliary neurotrophic factor (CNTF), which is present at high levels in the Schwann cell cytoplasm, is involved in the maintenance of these structures, we have examined lumbar ventral root nerve fibers of alpha-motor neurons by electron microscopy in 3- and 9-month-old Cntf null ((-/-)) mutant mice. Nerve fibers and nodes of Ranvier in 3-month-old Cntf(-/-) mutants appeared morphologically normal, except that ASNs were more voluminous in the mutants than in wild-type control animals at this age. In 9-month-old Cntf(-/-) animals, morphological changes, such as reduction in nerve fiber and axon diameter, myelin sheath disruption, and loss of ASNs at nodes of Ranvier, were observed. These findings suggest that endogenous CNTF, in addition to its role in promoting motor neuron survival and regeneration, is needed for long-term maintenance of alpha-motor nerve fibers. The premature loss of paranodal ASNs in animals lacking CNTF, which seems to be a defect related to a disturbed interaction in the nodal region between the axon and its myelinating Schwann cells, could impede the maintenance of a normal milieu in the motor axon, preceding more general neuronal damage.

Georgiou, T., M. McKibbin, et al. (2003). "Bilateral third-nerve palsy with aberrant regeneration in Guillain-Barre syndrome." Eye 17(2): 254-6.
 
George, L. T., T. M. Myckatyn, et al. (2003). "Functional recovery and histomorphometric assessment following tibial nerve injury in the mouse." J Reconstr Microsurg 19(1): 41-8.
 Longitudinal studies have established that functional recovery following sciatic nerve injury can be evaluated in the mouse. Injury to the tibial nerve offers several advantages to sciatic nerve injury, including improved lower extremity sensation and end-organ reinnervation. Functional recovery following tibial nerve crush injury was studied in 55 C3H mice randomized into five groups harvested for histomorphometric evaluation from either normal nerves or 2, 3, 4, or 6 weeks postoperatively. Walking tracks were obtained preoperatively, and at regular intervals postoperatively, and foot print lengths measured. Significant normalization of print length occurred 14 days postoperatively, and complete recovery was noted 28 days postoperatively. Significant histomorphologic evidence of neuroregeneration was detected between 2 and 4 weeks postoperatively. Injury to the tibial nerve is a viable alternative to the sciatic nerve for studying neural regeneration in mice, and the print length factor can be used to monitor functional recovery in this model.

Gericke, C. A., U. E. Lang, et al. (2003). "Nerve growth factor response to excitotoxic lesion of the cholinergic basal forebrain is slightly impaired in aged rats." J Neural Transm 110(6): 627-39.
 Nerve growth factor (NGF) promotes survival and function of basal forebrain cholinergic neurons. We studied NGF and choline acetyltransferase (ChAT) activity after partial quisqualic acid induced lesions of the basal forebrain in 3 and 27 months-old rats, in order to investigate whether NGF-related regeneration is disturbed in old age. 2 weeks post lesion, ChAT activity decreased by 25 to 32% in adult and old rats. 3 months post lesion, the ChAT deficit receded in adult rats, but remained unchanged in old rats. 2 weeks post lesion, NGF levels were reduced by 36 to 44%, but there was no significant difference between adult and old rats. 3 months post lesion, we found increased NGF levels by 44% in the posterior cortex of adult rats. These results indicate that the compensatory NGF increase in the posterior cortex after partial cholinergic lesion of the basal forebrain is slightly impaired in old age.

Germain, F., E. Fernandez, et al. (2003). "Morphometrical analysis of dendritic arborization in axotomized retinal ganglion cells." Eur J Neurosci 18(5): 1103-9.
 It has been reported that section of the optic nerve in mammals causes death in >90% of the retinal ganglion cells (RGCs). The cells which survive the section experience an irreparable loss of many of their dendritic segments and a rapid retraction of the dendritic tree. However, some growth cones and abnormal processes have been also reported. Our aim was to make a quantitative study of the morphological changes found in rabbit RGCs after optic nerve section. The morphometrical analysis of the RGCs which survived the axotomy showed an increase in the diameter of the soma and a significant increase in the area of the dendritic field; also, the length of the dendritic segments was significantly longer in axotomized RGCs than in control cells. Terminal dendritic segments (T) and preterminal segments (PT) were both measured in control and axotomized cells; the length ratio of T : PT segments was significantly greater in the axotomized cells than in the controls. We conclude that RGCs which survived the axotomy experienced a significant growth of their terminal dendritic branches.

Gervasi, C., A. Thyagarajan, et al. (2003). "Increased expression of multiple neurofilament mRNAs during regeneration of vertebrate central nervous system axons." J Comp Neurol 461(2): 262-75.
 Characteristic changes in the expression of neuronal intermediate filaments (nIFs), an abundant cytoskeletal component of vertebrate axons, accompany successful axon regeneration. In mammalian regenerating PNS, expression of nIFs that are characteristic of mature neurons becomes suppressed throughout regeneration, whereas that of peripherin, which is abundant in developing axons, increases. Comparable changes are absent from mammalian injured CNS; but in goldfish and lamprey CNS, expression of several nIFs increases during axon regrowth. To obtain a broader view of the nIF response of successfully regenerating vertebrate CNS, in situ hybridization and video densitometry were used to track multiple nIF mRNAs during optic axon regeneration in Xenopus laevis. As in other successfully regenerating systems, peripherin expression increased rapidly after injury and expression of those nIFs characteristic of mature retinal ganglion cells decreased. Unlike the decrease in nIF mRNAs of regenerating PNS, that of Xenopus retinal ganglion cells was transient, with most nIF mRNAs increasing above normal during axon regrowth. At the peak of regeneration, increases in each nIF mRNA resulted in a doubling of the total amount of nIF mRNA, as well as a shift in the relative proportions contributed by each nIF. The relative proportions of peripherin and NF-M increased above normal, whereas proportions of xefiltin and NF-L decreased and that of XNIF remained the same. The increases in peripherin and NF-M mRNAs were accompanied by increases in protein. These results are consistent with the hypothesis that successful axon regeneration involves changes in nIF subunit composition conducive to growth and argue that a successful injury response differs between CNS and PNS.

Geuna, S., S. Raimondo, et al. (2003). "Schwann-cell proliferation in muscle-vein combined conduits for bridging rat sciatic nerve defects." J Reconstr Microsurg 19(2): 119-23; discussion 124.
 Among the various grafting procedures that have been studied as alternatives to traditional fresh nerve autografts for the repair of severed peripheral nerves, muscle-vein-combined graft conduits have recently been devised and successfully employed. In the present study, the early presence, origin, and proliferation activity of Schwann cells (SCs) along this particular type of biological graft conduit have been investigated, using antibodies directed against glial fibrillar acid protein (GFAP), a protein that is specifically expressed in glial cells, and proliferating cell nuclear antigen (PCNA), a protein that is expressed by cells during DNA synthesis. Results showed that the muscle-vein-combined graft was progressively invaded by a number of GFAP-immunopositive SCs, many of which were also found to be immunopositive for PCNA, thus demonstrating that their proliferation continues to occur inside the graft. Among the molecules that could be involved in the stimulation of Schwann-cell proliferation is neuregulin-1 (NRG-1) that mediates its effects by binding to the ErbB receptor tyrosine kinase family. In the present study, the authors report on the RT-PCR analysis for NRG-1 and ErbB3 mRNAs, showing an overall increase in the content of these transcripts inside the muscle-vein-combined graft. These results suggest that the muscle-vein-combined graft conduit constitutes an environment favorable to potentiate Schwann-cell proliferation during the early regeneration phases.

Giampaoli, S., S. Bucci, et al. (2003). "Expression of FGF2 in the limb blastema of two Salamandridae correlates with their regenerative capability." Proc R Soc Lond B Biol Sci 270(1530): 2197-205.
 Limb regenerative potential in urodeles seems to vary among different species. We observed that Triturus vulgaris meridionalis regenerate their limbs significantly faster than T. carnifex, where a long gap between the time of amputation and blastema formation occurs, and tried to identify cellular and molecular events that may underlie these differences in regenerative capability. Whereas wound healing is comparable in the two species, formation of an apical epidermal cap (AEC), which is required for blastema outgrowth, is delayed for approximately three weeks in T. carnifex. Furthermore, fewer nerve fibres are present distally early after amputation, consistent with the late onset of blastemal cell proliferation observed in T. carnifex. We investigated whether different expression of putative blastema mitogens, such as FGF1 and FGF2, in these species may underlie differences in the progression of regeneration. We found that whereas FGF1 is detected in the epidermis throughout the regenerative process, FGF2 onset of expression in the wound epidermis of both species coincides with AEC formation and initiation of blastemal cell proliferation, which is delayed in T. carnifex, and declines thereafter. In vitro studies showed that FGF2 activates MCM3, a factor essential for DNA replication licensing activity, and can be produced by blastemal cells themselves, indicating an autocrine action. These results suggest that FGF2 plays a key role in the initiation of blastema growth.

Gibran, N. S., R. Tamura, et al. (2003). "Human dermal microvascular endothelial cells produce nerve growth factor: implications for wound repair." Shock 19(2): 127-30.
 Following cutaneous injury, sensory nerves regenerate into the dermis and epidermis. Tissues that are innervated by sensory nerves synthesize neurotrophins such as nerve growth factor (NGF). The close anatomic proximity of nerves and capillaries throughout the skin suggests that mutual regulation may exist between nerve fibers and microvascular endothelial cells (MECs) during wound repair. Release of the neuropeptide substance P by sensory nerves induces endothelial cell rounding, capillary leak, and cytokine upregulation. We propose that dermal endothelial cells produce neurotrophins required for nerve fiber maintenance and regeneration. In this study, we demonstrate that substance P stimulates NGF messenger RNA expression by cultured human dermal MECs. Likewise, enzyme-linked immunosorbant assay demonstrated that conditioned medium from cultured dermal MECs contains NGF. NGF bioactivity in the supemates was verified by conditioned medium-induced clonal rat pheochromocytoma (PC-12) cell differentiation. This activity was inhibited by anti-NGF antibodies. Therefore, we have demonstrated that substance P, an inflammatory neuropeptide released by sensory nerve fibers, induces endothelial cells to produce NGF. Our data suggest that MECs may be unrecognized contributors to nerve regeneration after cutaneous injury.

Gilhuis, H. J., C. H. Beurskens, et al. (2003). "Contralateral reinnervation of midline muscles in nonidiopathic facial palsy." J Clin Neurophysiol 20(2): 151-4.
 The purpose of this study was to analyze contralateral reinnervation of the facial nerve in eight patients with complete facial palsy after surgery or trauma and seven healthy volunteers. All patients had contralateral reinnervation of facial muscles as demonstrated by electrical nerve stimulation versus none of the control subjects. Four patients had facial muscle movements at the site of the damaged nerve. In one patient this was entirely the result of contralateral reinnervation, whereas the other three patients had innervation both ipsilaterally and contralaterally. This implies that renewed facial muscle activity should be examined considering the origin of the reinnervation, either contralateral or ipsilateral. Contralateral reinnervation is a common phenomenon after total facial palsy and can occur alongside ipsilateral reinnervation. It can be mistaken for adequate reinnervation of the damaged nerve, causing postponement of dynamic reconstruction therapy.

Gillon, R. S., Q. Cui, et al. (2003). "Effects of immunosuppression on regrowth of adult rat retinal ganglion cell axons into peripheral nerve allografts." J Neurosci Res 74(4): 524-32.
 Analysis of the effectiveness of allografts and immunosuppression in the repair of nerve defects in the adult peripheral nervous system (PNS) has a long experimental and clinical history. There is little information, however, on the use of allografts in peripheral nerve (PN) transplantation into the injured central nervous system (CNS). We assessed the ability of PN allografts (from Dark-Agouti rats) to support regeneration of adult rat retinal ganglion cell (RGC) axons in immunosuppressed host Lewis rats. PN allografts were sutured onto intraorbitally transected optic nerves. Three weeks after grafting, regenerating RGC axon numbers were determined using retrograde fluorescent labelling, and total axons within PN grafts were assessed using pan-neurofilament immunohistochemistry. In the absence of immunosuppression, PN allografts contained few axons and there were very few labelled RGC. These degenerate grafts contained many T cells and macrophages. Systemic (intraperitoneal) application of the immunosuppressants cyclosporin-A or FK506 reduced cellular infiltration into allografts and resulted in extensive axonal regrowth from surviving RGCs. The average number of RGCs regenerating axons into immunosuppressed allografts was not significantly different from that seen in PN autografts in rats sham-injected with saline. Many pan-neurofilament-positive axons, a proportion of which were myelinated, were seen in immunosuppressed allografts, particularly in proximal regions of the grafts toward the optic nerve-PN interface. This study demonstrates that PN allografts can support axonal regrowth in immunosuppressed adult hosts, and points to possible clinical use in CNS repair.

Gingras, M., J. Bergeron, et al. (2003). "In vitro development of a tissue-engineered model of peripheral nerve regeneration to study neurite growth." Faseb J 17(14): 2124-6.
 A unique tissue-engineered model of peripheral nerve regeneration was developed in vitro to study neurite outgrowth. Mouse dorsal root ganglia neurons were seeded on a collagen sponge populated with human endothelial cells and/or human fibroblasts. Addition of nerve growth factor (NGF; 10 ng/ml) was not required for sensory neurons survival but was necessary to promote neurite outgrowth, as assessed by immunostaining of the 150 kDa neurofilament. A vigorous neurite elongation was detected inside the reconstructed tissue after 14 and 31 days of neurons culture, reaching up to 770 microm from day 14. Axons were often observed closely associated with the capillary-like tubes reconstructed in the model, in a similar pattern as in the human dermis. The presence of endothelial cells induced a significant increase of the neurite elongation after 14 days of culture. The addition of human keratinocytes totally avoided the twofold decrease in the amount of neurites observed between 14 and 31 days in controls. Besides the addition of NGF, axonal growth did not necessitate B27 supplement or glial cell coculture to be promoted and stabilized for long-term culture. Thus, this model might be a valuable tool to study the effect of various cells and/or attractive or repulsive molecules on neurite outgrowth in vitro.

Gingras, M., I. Paradis, et al. (2003). "Nerve regeneration in a collagen-chitosan tissue-engineered skin transplanted on nude mice." Biomaterials 24(9): 1653-61.
 A reconstructed skin made of a collagen-chitosan sponge seeded with human fibroblasts and keratinocytes and grown in vitro for 31 days was developed for the treatment of deep and extensive burns. The aim of this study was to assess whether this tissue-engineered skin could promote nerve regeneration in vivo, since recovery of sensation is a major concern for burnt patients. The human reconstructed skin was transplanted on the back of nude mice and the growth of nerve fibres within it was assessed 40, 60, 90 and 120 days after graft. Nerve growth was monitored by confocal microscopy using immunohistochemical staining of PGP 9.5 and 150 kD neurofilament, while Schwann cell migration was observed using protein S100 expression and laminin deposition. Nerve growth was first detected 60 days after transplantation and was more abundant 90 and 120 days after graft. Linear arrangements of Schwann cells were observed in the graft as early as 40 days after graft. Nerve growth was observed along these Schwann cell extensions 60 days after transplantation. We conclude that the three-dimensional architecture of the collagen-chitosan tissue-engineered skin sponge encourages nerve growth. This result provides new perspectives to increase nerve regeneration within the tissue-engineered skin by linkage of neurotrophic factors in the sponge before transplantation.

Glockner, F. and T. G. Ohm (2003). "Hippocampal apolipoprotein D level depends on Braak stage and APOE genotype." Neuroscience 122(1): 103-10.
 Apolipoprotein (APO, gene; apo, protein) D, a member of the lipocalin family, has been implicated in several, pathological conditions but neither its physiologic function(s) nor ligand(s) has been clearly identified so far. Presuming a role in nerve de- and regeneration, several groups investigated apoD alterations in Alzheimer's disease (AD). Reported data, however, were not unanimous. We determined apoD protein levels in the hippocampus in a large, carefully matched autopsy case sample. ApoD levels were compared with the severity of neuropathological changes as determined by the Braak classification and with APOE genotype, a major risk factor for developing AD. ApoD was found to be related to the severity of AD-related neurofibrillary (NF) changes and not to old age alone. No correlation was found to amyloid deposits. Brain samples with widespread NF changes showed significantly higher apoD than cases with low Braak stages. This increase, however, was restricted to the APOE epsilon3/3 group, whereas the APOE epsilon4 group did not show significant variations in hippocampal apoD.

Gojo, S. and A. Umezawa (2003). "Plasticity of mesenchymal stem cells--regenerative medicine for diseased hearts." Hum Cell 16(1): 23-30.
 The phenomenon of regeneration is of growing interest to medical researchers. Until recently this was an area in which research in flatworms and newts predominated, but there is now a proliferation of research concerning regeneration in virtually all of the organs, not only the heart. One of the object is restoration of function to a failing heart through cell transplantation, and there have been many reports seeking donor sources of somatic stem cells, i.e.: stem cells in marrow or skeletal muscle and ES cells, beginning with those in embryonic myocardial cell transplant experiments. In particular, reports of mesenchymal stem cell differentiation into nerve cell, myocardial cell, skeletal muscle cell, and vascular endothelial cell series have drawn attention to cell plasticity, and clinical applications are awaited.

Gold, B. G. and J. E. Villafranca (2003). "Neuroimmunophilin ligands: the development of novel neuroregenerative/ neuroprotective compounds." Curr Top Med Chem 3(12): 1368-75.
 FK506 (tacrolimus), initially developed as an immunosuppressant drug, represents a class of compounds with potential high impact for the treatment of human neurological disorders. While immunosuppression is mediated by the 12-kD FK506-binding-protein (FKBP-12), the neurite elongation activity of FK506 involves FKBP-52 (also known as FKBP-59 or Hsp-56), a component of mature steroid receptor complexes: FKBP-52 binds to Hsp-90, which bind to p23 and the steroid receptor protein to form the complex. The brief review focuses on how three classes of compounds (FK506 derivatives, steroid hormones, and ansamycin anti-cancer drugs, e.g., geldanamycin) increase neurite elongation/nerve regeneration (axonal elongation). A model is presented whereby neurite elongation is elicited by compounds that bind to steroid receptor chaperone proteins (e.g., FKBP-52 and Hsp-90) and thereby disrupt mature steroid receptor complexes (comprising FKBP-52, Hsp-90 and p23 in addition to the steroid receptor binding protein). Disruption of the complex leads to a "gain-of-function" whereby one or more of these steroid receptor chaperone proteins (i.e, FKBP-52, Hsp-90 or p23) activates mitogen-associated protein (MAP) kinase/extracellular signal-regulated kinase (ERK) pathway. Thus, the neurotrophic actions of these distinct classes of compounds can be understood from their ability to bind steroid receptor chaperones, thereby providing a unique receptor-mediated means to activate the ERK pathway. These studies thereby shed new light on the intrinsic mechanism regulating axonal elongation. Furthermore, this mechanism may also underlie calcineurin-independent neuroprotective actions of FK506. We suggest that components of steroid receptor complexes are novel targets for the design of neuroregenerative/neuroprotective drugs.

Goldberg, J. L. (2003). "How does an axon grow?" Genes Dev 17(8): 941-58.
 
Gordon, T., O. Sulaiman, et al. (2003). "Experimental strategies to promote functional recovery after peripheral nerve injuries." J Peripher Nerv Syst 8(4): 236-50.
 The capacity of Schwann cells (SCs) in the peripheral nervous system to support axonal regeneration, in contrast to the oligodendrocytes in the central nervous system, has led to the misconception that peripheral nerve regeneration always restores function. Here, we consider how prolonged periods of time that injured neurons remain without targets during axonal regeneration (chronic axotomy) and that SCs in the distal nerve stumps remain chronically denervated (chronic denervation) progressively reduce the number of motoneurons that regenerate their axons. We demonstrate the effectiveness of low-dose, brain-derived neurotrophic and glial-derived neurotrophic factors to counteract the effects of chronic axotomy in promoting axonal regeneration. High-dose brain-derived neurotrophic factor (BDNF) on the other hand, acting through the p75 receptor, inhibits axonal regeneration and may be a factor in stopping regenerating axons from forming neuromuscular connections in skeletal muscle. The immunophilin, FK506, is also effective in promoting axonal regeneration after chronic axotomy. Chronic denervation of SCs (>1 month) severely deters axonal regeneration, although the few motor axons that do regenerate to reinnervate muscles become myelinated and form enlarged motor units in the reinnervated muscles. We found that in vitro incubation of chronically denervated SCs with transforming growth factor-beta re-established their growth-supportive phenotype in vivo, consistent with the idea that the interaction between invading macrophages and denervated SCs during Wallerian degeneration is essential to sustain axonal regeneration by promoting the growth-supportive SC phenotype. Finally, we consider the effectiveness of a brief period of 20 Hz electrical stimulation in promoting the regeneration of axons across the surgical gap after nerve repair.

Gotz, M. and D. Steindler (2003). "To be glial or not-how glial are the precursors of neurons in development and adulthood?" Glia 43(1): 1-3.
 
Gruart, A., M. Streppel, et al. (2003). "Motoneuron adaptability to new motor tasks following two types of facial-facial anastomosis in cats." Brain 126(Pt 1): 115-33.
 The ability of the facial motor system to adapt to a new motor function was studied in alert cats after unilateral transection, 180 degrees rotation and suture of the zygomatic nerve, or transection and cross-anastomosis of the proximal stump of the buccal nerve to the distal stump of the zygomatic nerve. These procedures induced reinnervation of the orbicularis oculi (OO) muscle by different OO- or mouth-related facial motoneurons. Eyelid movements and the electromyographic activity of the OO muscle were recorded up to 1 year following the two types of anastomosis. Animals with a zygomatic nerve rotation recovered spontaneous and reflex responses, but with evident deficits in eyelid kinematics, i.e. the proper regional distribution of OO motor units was disorganized by zygomatic nerve rotation and resuture, producing a permanent defect in eyelid motor performance. Following buccal-zygomatic anastomosis, the electrical activity of the OO muscle was recovered after 6-7 weeks, but air puff-, flash- and tone-evoked reflex blinks never reached the control values on the operated side. Electromyographic OO activities and lid movements corresponding to licking and deglutition activities were observed on the operated side in buccal-zygomatic anastomosed animals up to 1 year following surgery. Mouth-related facial motoneurons did not readapt their discharges to the kinetic, timing and oscillatory properties of OO muscle fibres. A significant hyper-reflexia was observed following both types of nerve repair in response to air puffs, but not to light flashes or tones. In conclusion, adult mammal facial premotor circuits maintain their motor programmes when motoneurons are induced to reinnervate a foreign muscle, or even a new set of muscle fibres.

Gschwendtner, A., Z. Liu, et al. (2003). "Regulation, cellular localization, and function of the p75 neurotrophin receptor (p75NTR) during the regeneration of facial motoneurons." Mol Cell Neurosci 24(2): 307-22.
 The common neurotrophin receptor (p75NTR) is a member of the tumor necrosis factor receptor superfamily and binds the neurotrophins nerve growth factor, brain derived neurotrophic factor, neurotrophin-3, and neurotrophin-4. P75NTR is expressed on developing motoneurons and is reexpressed on adult motoneurons under pathological conditions such as nerve trauma or neurodegeneration. Here we examined the regulation and function of p75NTR during regeneration after peripheral transection of the facial nerve of adult mice. Axotomy led to a strong increase in p75NTR immunoreactivity on the injured and regenerating facial motoneurons and on denervated Schwann cells. Cellular colocalization also revealed p75NTR immunoreactivity on neighboring blood vessels and cells in the injured nerve, but not on activated GFAP+ astrocytes or alphaMbeta2+ microglia and macrophages. To determine the function of this receptor we examined the effects of p75NTR deficiency on neuroglial activation, on the speed of axonal regeneration, and on neuronal survival after facial axotomy in two different transgenic mouse lines carrying targeted insertions exon 4 (p75e4-/-) or exon 3 (p75e3-/-) of the p75NTR gene. In both animal models absence of p75NTR led to a twofold, early increase in the number of CD3+. T-cells and in the microglial immunoreactivity for the alpha5beta1, alpha6beta1, and alphaMbeta2 integrins at day 4 in the facial nucleus and in the crushed facial motor nerve. No changes were observed in the number of reactive GFAP+ astrocytes or on late microglial and lymphocyte responses. The rate of axonal elongation in the crushed facial nerve, as well as neuronal survival, was found to be unaffected. Overall, the current study shows that the p75NTR receptor plays an important regulatory role in early neuroglial and immune activation.

Grutzner, P. A., W. Haase, et al. (2003). "[Comparative examination between an angle stable, monokortikal osteosynthesis technique with the conventional plate osteosynthesis at the anterior arm shaft fracture]." Unfallchirurg 106(2): 121-6.
 With a retrospective Follow-up essay under the use of Matched peer variables the wellbeing course was examined by patient pairs (128 patients) assigned to 64 individually with fractures of the anterior arm shaft. A group which treats others with 2.7 or 3.5 mm DCP/LC-DCP got with the AO Point Contact basic gate (PC-Fix).The well-being course data count after the implantation on a period of 18 months.The Follow-up-rate was 100% for this time period.The patients became for each other on reason of the criteria: assigned to fracture classification, soft partial loss, accompanying injuries and age.Possible complications were: implantation conditional nerve damages, infections, implant failures, delayed healings, pseudarthroses, motion reductions and synostoses.Complications appeared (PC-Fix at 13 patients: respect, DCP: 5).The statistical testing didn't yield any statistically significant advantage for one for the two implants at a p-value of 0.5811 for.

Guntinas-Lichius, O. and C. Wittekindt (2003). "The role of growth factors for disease and therapy in diseases of the head and neck." DNA Cell Biol 22(9): 593-606.
 Growth factors are a large family of polypeptide molecules that regulate cell division in many tissues by autocrine or paracrine mechanisms. Depending on what receptors are activated, growth factors can initiate mitogenic, antiproliferative, or trophic effects, that is, growth factors act as positive or negative modulators of cell proliferation. Therefore, growth factors do not only play an important role in embryonic development and adult tissue homeostasis, but also in pathological situations like infection, wound healing, and tumorigenesis. Consequently, the application of growth factors, or vice versa the application of substances which are directed against growth factors like antigrowth factor antibodies, may have therapeutic applications. This review provides a brief account of what we know regarding growth factors in otorhinolaryngology, particularly in the field of otology, wound healing, oncology, peripheral nerve regeneration, and rhinology.

Gupta, R., Y. M. Lin, et al. (2003). "Macrophage recruitment follows the pattern of inducible nitric oxide synthase expression in a model for carpal tunnel syndrome." J Neurotrauma 20(7): 671-80.
 Chronic nerve compression (CNC) induces a permeability change in neural vasculature. As recent evidence has shown that an alteration in reactive oxidative species (ROS) is related to neural degradation and regeneration, we evaluated whether inducible nitric oxide synthase (iNOS) plays a role in a rat model for CNC. Semi-quantitative analysis of iNOS mRNA and protein were performed with in situ hybridization and immunohistochemistry, respectively, at 3, 5, and 9 months post-operatively. At 3 months, iNOS mRNA was up-regulated in the perineurium of the proximal nerve with detectable changes in compressed and distal nerve segments. This expression continued to increase in the perineurium of 5-month proximal and compressed nerve segments with distal nerve demonstrating only a slight up-regulation of iNOS mRNA. At 9 months, iNOS mRNA expression was observed in both compressed and distal nerve. iNOS protein expression followed the same pattern of iNOS mRNA. As the perineurium is the blood-nerve barrier, the data suggests that these changes maybe mediated at the level of the perineurium. As macrophages release iNOS, we also evaluated whether macrophage recruitment followed the same pattern as iNOS expression. The results of ED-1 immunostaining for macrophages indicate that macrophages were localized to the outer one-third of cross sections during early time points. At later time points, macrophages were distributed diffusely throughout the nerve sections. Contrary to Wallerian degeneration, which elicits a relatively immediate signal for macrophage recruitment, CNC provides a slow, sustained stimulus for macrophage recruitment, which may be responsible for the up-regulation of iNOS gene expression.

Gupta, R. and O. Steward (2003). "Chronic nerve compression induces concurrent apoptosis and proliferation of Schwann cells." J Comp Neurol 461(2): 174-86.
 Chronic nerve compression (CNC), as in carpal tunnel syndrome, is a common cause of peripheral nerve dysfunction in humans. Previous studies using animal models have demonstrated progressive demyelination and a slowing of nerve conduction velocity. To characterize the Schwann cell response to CNC, we evaluated total Schwann cell number, apoptosis, and proliferation in an animal model of CNC. Design-based stereologic techniques revealed a striking transient increase in Schwann cell number following CNC. Schwann cell number increased sixfold relative to the normal nerve at the site of compression at 1 month and then slowly declined toward control levels. Nevertheless, assays of apoptosis (TUNEL and an antipoly-ADP-ribose polymerase labeling assays) revealed extensive Schwann cell apoptosis at 2 weeks postcompression, which is during the time when Schwann cell number was increasing. Electron microscopic analysis confirmed that these dramatic changes in Schwann cells occurred in the absence of axon degeneration and axonal swelling and before there were any detectable alterations in nerve conduction velocity. Counts of bromodeoxyuridine-labeled Schwann cells revealed that proliferation occurred concurrently with ongoing apoptosis. To define further the possible mitogenic properties of mechanical stimuli on Schwann cells, we used an in-vitro model to deliver shear stress in the form of laminar fluid flow to pure populations of Schwann cells and confirmed that mechanical stimuli induce Schwann cell proliferation. Our findings indicate that chronic nerve compression induces Schwann cell turnover with minimal axonal injury and support the idea that mechanical stimuli have a direct mitogenic effect on Schwann cells.

Haase, S. C., J. M. Rovak, et al. (2003). "Recovery of muscle contractile function following nerve gap repair with chemically acellularized peripheral nerve grafts." J Reconstr Microsurg 19(4): 241-8.
 Acellular nerve grafts have emerged as a possible alternative for reconstruction of short (<2 cm) peripheral nerve gaps. Axonal regeneration has been demonstrated within the nerve constructs. However, very little work has been done to demonstrate both axonal regeneration and recovery of motor function following peripheral nerve gap repair with acellular nerve constructs. The authors hypothesized that chemically acellularized nerve grafts can support axonal regeneration and provide functional reinnervation of rat hindlimb muscles with equivalent efficiency to peripheral nerve autografts. Peroneal nerves were harvested from adult rats and chemically acellularized. Two- and 4-cm peroneal nerve gaps were reconstructed with either a cellular autograft or an acellular isograft. Functional recovery was evaluated with walking-track analyses and measurement of maximum tetanic isometric force (F 0 ) of the extensor digitorum longus (EDL) muscle. Walking-track analysis revealed no statistically significant difference in functional recovery in rats undergoing reconstruction of 2-cm nerve gaps with acellular isografts or cellular autografts. Maximum tetanic isometric force measurements revealed a 60 percent force deficit in EDL muscles reinnervated by 2-cm acellular nerve grafts, compared to cellular autografts. Four-centimeter acellular grafts failed to support any significant EDL muscle reinnervation. This study demonstrates that chemically acellularized peripheral nerve supports axonal regeneration and functional reinnervation across 2-cm nerve gaps, and may potentially serve as an appropriate scaffold for reintroducing cellular elements, adhesion molecules, or growth factors for repair of longer nerve gaps.

Hadlock, T. A., T. Sheahan, et al. (2003). "Biologic activity of nerve growth factor slowly released from microspheres." J Reconstr Microsurg 19(3): 179-84; discussion 185-6.
 Efficient and sustained delivery of neurotrophic factors to the regenerating nerve in biologically active form presents a challenge. Protein delivery in biodegradable microsphere vehicles has been difficult, based on destabilization and breakdown during both the loading and release phases. This study examines the extravasation and stability of Nerve Growth Factor (NGF) in polylactic-co-glycolic acid (PLGA) microspheres, via both ELISA and PC-12 bioassays. PLGA microspheres co-loaded with bovine serum albumin (BSA) and NGF were prepared by a water-in-oil-in-water (W/O/W) technique, using chloroform for the organic phase and 1 percent polyvinyl alcohol (PVA) for the emulsion step. Aliquots of lyophilized microspheres were incubated in double distilled water (dd H2O) at 37 degrees C, and the supernatants assayed over time for NGF activity. ELISA was utilized for quantitative determination of NGF concentration, and a PC-12 cell neurite outgrowth assay assessed biologic activity. Both ELISA and PC-12 assays demonstrated the extravasation of NGF from microspheres. Over time, the predicted concentration of NGF via the two assays differed, suggesting possible preservation of recognizable epitopes for ELISA, but loss of biologic activity. NGF can be stored and released from microspheres. Extravasation studies should include biologically relevant assays for activity.

Hagino, S., K. Iseki, et al. (2003). "Expression pattern of glypican-1 mRNA after brain injury in mice." Neurosci Lett 349(1): 29-32.
 Glypican-1, a heparan sulfate proteoglycan, is expressed in various tissues including developing and postnatal central nervous system. It serves as a receptor for heparin-binding molecules such as fibroblast growth factors (FGFs). We investigated whether glypican-1 was expressed after brain injury in adult mice. In situ hybridization study showed that glypican-1 mRNA was expressed in the region surrounding necrotic tissue, and that the signal intensity peaked 7 days after the cryo-injury. In addition, both FGF-2 and amyloid precursor protein (APP) were concurrently upregulated and colocalized with glypican-1 mRNA. Since FGF-2 and APP can bind to glypican-1 in vitro, the present study suggested that their autocrine/paracrine interactions with glypican-1 may be involved in neuronal regeneration and/or neurite-outgrowth inhibition after brain injury.

Hagino, S., K. Iseki, et al. (2003). "Slit and glypican-1 mRNAs are coexpressed in the reactive astrocytes of the injured adult brain." Glia 42(2): 130-8.
 The slit family serves as a repellent for growing axons toward correct targets during neural development. A recent report describes slit mRNAs expressed in various brain regions in adult rats. However, their functions in the adult nervous system remain unknown. In the present study, we investigated whether slit mRNAs were expressed in the cryo-injured brain, using in situ hybridization. All slit family members were expressed at the lesion. Slit2 mRNA was the most intensely expressed in the cells surrounding the necrotic tissue. A double-labeling study showed that slit2 mRNA was expressed in the glial fibrillary acidic protein (GFAP)-positive reactive astrocytes. In addition, glypican-1, a heparan sulfate proteoglycan that serves as a high-affinity receptor for Slit protein, was coexpressed with slit2 mRNA in the reactive astrocytes. These findings suggested that slit2 might prevent regenerating axons from entering into the lesion in concert with glypican-1.

Halfpenny, C. A. and N. J. Scolding (2003). "Immune-modifying agents do not impair the survival, migration or proliferation of oligodendrocyte progenitors (CG-4) in vitro." J Neuroimmunol 139(1-2): 9-16.
 Limited intrinsic myelin repair occurs in multiple sclerosis (MS), mediated by oligodendrocyte progenitors that divide and migrate into demyelinated lesions. Experimental remyelination suggests that this repair restores function and may protect axons from subsequent degeneration. Immunomodulatory drugs such as corticosteroids, interferon-beta and azathioprine are widely used in MS. However, their influence on disease progression is modest, for reasons that are not fully explained. The direct effects of these drugs on remyelination biology remain relatively unexplored. We have investigated the effect of these MS therapies on oligodendrocyte progenitors to identify whether drug treatment might directly compromise repair, either therapeutic or spontaneous. None of these drugs affected CG-4 survival, migration or proliferation.

Hanani, M., O. Ledder, et al. (2003). "Regeneration of myenteric plexus in the mouse colon after experimental denervation with benzalkonium chloride." J Comp Neurol 462(3): 315-27.
 Recent reports suggest a far greater plasticity in nerve tissue than previously believed. As the digestive tract is exposed to a variety of insults, this question is relevant to enteric nerves, but little is known about their ability to recover from damage. To address this problem, we ablated the myenteric plexus of the mouse colon with the detergent benzalkonium chloride (BAC) and followed the ensuing morphologic changes for up to 60 days by using light- and electron microscopy. We found that, 2 days after BAC application, the treated area was essentially devoid of intact nerve elements. From day 7, new nerve fibers were observed within the denervated region. This growth progressed until, at days 30-60, newly grown nerve fibers were present in most of this region, and the pattern of muscle innervation was similar to the normal one. At least part of these fibers originated at neurons within intact ganglia surrounding the denervated region. The cross-sectional area of neurons near the denervated region at day 14 was 52% greater than controls. Glial cells were closely associated with the regenerating nerve fibers. From day 14 onward, we observed undifferentiated cells and differentiating neurons in ganglia surrounding the denervated region, and by day 30, new neurons were present in the myenteric region, along with regenerating nerve fibers. We conclude that the myenteric plexus is endowed with a considerable ability of regeneration and plasticity. The results provide evidence for the presence of stem cells and for an adult neurogenesis in this plexus.

Hansson, T. and T. Brismar (2003). "Loss of sensory discrimination after median nerve injury and activation in the primary somatosensory cortex on functional magnetic resonance imaging." J Neurosurg 99(1): 100-5.
 OBJECT: The aim of this study was to assess the effects of median nerve injury and regeneration on neuronal activation in the somatosensory cortex by means of functional magnetic resonance (fMR) imaging and somatosensory evoked potentials (SSEPs). METHODS: Ten injured male patients (mean age 26 years) were examined 15 to 58 months after a total transection of the median nerve at the wrist that was repaired with epineural sutures. Two-point discrimination was lost in Digit II-III and sensory nerve conduction displayed decreased velocity (-29%) and amplitude (-84%) in the median nerve at the wrist. The fMR images were obtained during tactile stimulation (gentle strokes) performed separately on the volar surface of either Digit II-III or Digit IV-V (eight patients: two were excluded because of movement artifacts). The SSEPs were obtained using electrical stimulation proximal to the median nerve lesion. CONCLUSIONS: Patients with loss of sensory discrimination after median nerve damage and regeneration had larger areas of activation in fMR imaging near the contralateral central sulcus during tactile stimulation of the injured compared with the noninjured hand. The increase relative to the unaffected hand was 43% (p < 0.02) for Digit II-III stimulation and 46% (p < 0.02) for Digit IV-V stimulation. The SSEP data showed normal latency and amplitude. The enlarged area of cortical activation may be the result of reorganization, and it may indicate that larger cortical areas are involved in the discriminatory task after a derangement of the peripheral input.

Harada, F., N. Hoshino, et al. (2003). "The involvement of brain-derived neurotrophic factor (BDNF) in the regeneration of periodontal Ruffini endings following transection of the inferior alveolar nerve." Arch Histol Cytol 66(2): 183-94.
 The present study employed immunohistochemistry for protein gene product 9.5 (PGP 9.5) to examine the regeneration process of Ruffini endings, the primary mechanoreceptor in the periodontal ligament, in heterozygous mice with targeted disruption of the brain-derived neurotrophic factor (BDNF) gene and their littermates, following transection of the inferior alveolar nerve. When immunostained for PGP 9.5, periodontal Ruffini endings appeared densely distributed in the periodontal ligament of the heterozygous mice, but the density of the positively stained nerve fibers in the ligament was 20% lower than that in the control littermates. At 3 days after surgery, the PGP 9.5-positive neural elements had disappeared; they began to appear in the periodontal ligament of both animals at 7 days. However, the recovery pattern of the PGP 9.5-positive nerves differed between heterozygous and wild type mice, typical periodontal Ruffini endings morphologically identical to those in the control group appeared in the wild-type mice at 7 days, whereas such Ruffini endings were detectable in the heterozygous mice at 28 days, though much smaller in number. On day 28, when PGP 9.5-positive nerves were largely regenerated in wild type mice, their distribution was much less dense in the ligament of the heterozygous mice than in the non-treated heterozygous mice. The density of PGP 9.5-positive nerve fibers was significantly lower in the heterozygous mice than in wild type mice at any stage examined. These data showing that a reduced expression of BDNF causes delayed regeneration of the periodontal Ruffini endings suggest the involvement of BDNF in the regeneration process of these mechanoreceptors.

Harman, A. M., J. Rodger, et al. (2003). "PSA-NCAM is up-regulated during optic nerve regeneration in lizard but not in goldfish." Exp Neurol 182(1): 180-5.
 The addition of polysialic acid (PSA) to neural cell adhesion molecule (NCAM) facilitates axon growth. Here we use Western blots and immunohistochemistry to examine expression of PSA-NCAM during optic nerve regeneration. In lizard, retinal ganglion cell axons become transiently PSA-NCAM positive. By contrast, goldfish RGC axons are PSA-NCAM negative both in normal animals and throughout regeneration with the exception of a PSA-NCAM-positive fascicle arising from newly generated RGCs. Transient sialylation of NCAM in lizard may assist regeneration in the nonpermissive reptilian visual pathway and facilitate the reestablishment of a crude topographic map; down-regulation in the long term may contribute to the breakdown in topography. The lack of sialylation in goldfish presumably reflects the permissive nature of the substrate allowing axon regeneration and the successful reestablishment of a topographic map.

Hase, S., K. Kobayashi, et al. (2003). "Transcriptional pattern of a novel gene, expressed specifically after the point-of-no-return during sexualization, in planaria." Dev Genes Evol 212(12): 585-92.
 We have investigated sexualization of asexual worms in the planarian Dugesia ryukyuensis. During sexualization there is a point from which an animal cannot return to the asexual state (point-of-no-return). To isolate the genes related to the point-of-no-return, we performed differential screening and isolated one novel gene that was expressed specifically in yolk glands of the worms after the point-of-no-return and named it Dryg. It encoded 655 amino acids with a predicted molecular mass of 79 kDa. We performed a series of experiments using Dryg as a molecular marker in the yolk gland. At first, we monitored how the yolk gland was formed during sexualization. The expression in sexualizing worms at stage 3 is limited to a single type of cell that has characteristics of neoblasts, the totipotent somatic cells; however, the expression is observed in the yolk gland in sexualized worms. Furthermore, we monitored yolk glands for expression during regeneration. The original yolk glands seem to disappear after ablation, then new yolk glands appeared along the ventral nerve cords. Because this expression pattern looks like that of sexualizing worms at stage 3, we speculate that yolk gland cells may differentiate from neoblasts during regeneration as observed during sexualization.

Hashimoto, N., H. Yamanaka, et al. (2003). "Increased expression of 3 beta-hydroxysteroid dehydrogenase mRNA in dorsal root ganglion neurons of adult rats following peripheral nerve injury." Neurosci Lett 340(1): 45-8.
 3beta-hydroxysteroid dehydrogenase (3beta-HSD) is an enzyme that converts pregnenolone to progesterone. It has been believed that 3beta-HSD is simply a converting enzyme of female steroid hormone. Recently, 3beta-HSD expressing cells were identified in the spinal cord. Steroid synthesis in the nervous system may indicate that steroid plays a role in the nervous system. We report here the increased expression of 3beta-HSD mRNA in the dorsal root ganglion (DRG) after peripheral nerve injury using reverse transcription-polymerase chain reaction and in situ hybridization histochemistry techniques. We detected only a few 3beta-HSD signals in the naive DRG, and found that 3beta-HSD mRNA expression increased 3 days after injury and this increase was still observed at 14 days. Our results suggest that progesterone may have a role in the process against neuronal injury or in regeneration in the peripheral nervous system.

Hastings, N. B. and E. Gould (2003). "Neurons inhibit neurogenesis." Nat Med 9(3): 264-6.
 
Hatoko, M., A. Tanaka, et al. (2003). "Expression of alpha, beta, and gamma catenins in vascularized and nonvascularized nerve grafts during the regeneration process." J Reconstr Microsurg 19(4): 271-8.
 The authors investigated the expression of three kinds of catenins (alpha, beta, gamma) in vascularized and non-vascularized nerve grafts, using the rat sciatic nerve model. The vascularized nerve, 15 mm in length, was elevated with its nutrient vessels in the left hindlimb of rats. In the right hindlimb, a 15-mm segment of the sciatic nerve was elevated (resected) without the nutrient vessels as a non-vascularized nerve. Both nerves were sutured to the original site. At various periods up to 14 weeks after operation, the entire graft was removed. Expression of three catenins was detected by Western blot analysis and histochemical staining, using the antibody to each catenin. The level of beta catenin increased during nerve regeneration in both the vascularized and non-vascularized grafts, while the level of alpha and gamma catenins did not increase in both grafts. There was no difference in the level of the three catenins between the two methods of nerve grafting. Histochemical findings showed that at the 4th and 14th postoperative weeks, alpha and gamma catenins were stained diffusely in both grafts, while beta catenin was stained around the regenerating axons in both grafts. The degree of beta catenin was greater in the 4th postoperative week than in the 14th postoperative week, but no obvious difference in the degree of staining of the three catenins between two grafts was found. These results suggest that beta catenin may play a different role from alpha and gamma catenins in nerve regeneration, and that the expression of these catenins is not influenced by vascularization of the nerve graft.

Hauben, E., A. Gothilf, et al. (2003). "Vaccination with dendritic cells pulsed with peptides of myelin basic protein promotes functional recovery from spinal cord injury." J Neurosci 23(25): 8808-19.
 Injury-induced self-destructive processes cause significant functional loss after incomplete spinal cord injury (SCI). Cellular elements of both the innate (macrophage) and the adaptive (T-cell) immune response can, if properly activated and controlled, promote post-traumatic regrowth and protection after SCI. Dendritic cells (DCs) trigger activation of effector and regulatory T-cells, providing a link between the functions of the innate and the adaptive immune systems. They also initiate and control the body's response to pathogenic agents and regulate immune responses to both foreign and self-antigens. Here we show that post-injury injection of bone marrow-derived DCs pulsed with encephalitogenic or nonencephalitogenic peptides derived from myelin basic protein, when administered (either systemically or locally by injection into the lesion site) up to 12 d after the injury, led to significant and pronounced recovery from severe incomplete SCI. No significant protection was seen in DC recipients deprived of mature T-cells. Flow cytometry, RT-PCR, and proliferation assays indicated that the DCs prepared and used here were mature and immunogenic. Taken together, the results suggest that the DC-mediated neuroprotection was achieved via the induction of a systemic T-cell-dependent immune response. Better preservation of neural tissue and diminished formation of cysts and scar tissue accompanied the improved functional recovery in DC-treated rats. The use of antigen-specific DCs may represent an effective way to obtain, via transient induction of an autoimmune response, the maximal benefit of immune-mediated repair and maintenance as well as protection against self-destructive compounds.

Hayat, S., C. B. Wigley, et al. (2003). "Intracellular calcium handling in rat olfactory ensheathing cells and its role in axonal regeneration." Mol Cell Neurosci 22(2): 259-70.
 Intracellular calcium handling by rat olfactory ensheathing cells (OECs) is implicated in their support for regrowth of adult CNS neurites in a coculture model of axonal regeneration. Pretreatment of OECs with BAPTA-AM to sequester glial intracellular calcium ([Ca(2+)](i)) reduces significantly the numbers of cocultured neurons regrowing neurites. The mean resting [Ca(2+)](i) of OECs cultured alone or with neurons was 300 nM in an external solution containing 2.5 mM calcium ([Ca(2+)](o)). In high [K(+)](o) or zero [Ca(2+)](o), resting [Ca(2+)](i) significantly decreased. [Ca(2+)](i) significantly increased when [Ca(2+)](o) was increased to 20 mM, lonomycin, thapsigargin, and thimerosal increased [Ca(2+)](i), and caffeine, ryanodine, and cyclopiazonic acid were without effect. Of the receptor agonists tested, none induced a change in [Ca(2+)](i). The calcium influx induced by high [Ca(2+)](o) was blocked by La(3+) and SKF96365, partially inhibited by Cd(2+), and insensitive to Ni(2+) and nifedipine. Pretreatment of OECs with La(3+) reduced neurite regrowth in cocultures in a concentration-dependent manner over the range that blocked the non-voltage-gated calcium flux through a putative TRP-like channel, which, we propose, is activated in OEC-mediated axonal regeneration.

He, X. L., J. F. Bazan, et al. (2003). "Structure of the Nogo receptor ectodomain: a recognition module implicated in myelin inhibition." Neuron 38(2): 177-85.
 Failure of axon regeneration in the adult mammalian central nervous system (CNS) is at least partly due to inhibitory molecules associated with myelin. Recent studies suggest that an axon surface protein, the Nogo receptor (NgR), may play a role in this process through an unprecedented degree of crossreactivity with myelin-associated inhibitory ligands. Here, we report the 1.5 A crystal structure and functional characterization of a soluble extracellular domain of the human Nogo receptor. Nogo receptor adopts a leucine-rich repeat (LRR) module whose concave exterior surface contains a broad region of evolutionarily conserved patches of aromatic residues, possibly suggestive of degenerate ligand binding sites. A deep cleft at the C-terminal base of the LRR may play a role in NgR association with the p75 coreceptor. These results now provide a detailed framework for focused structure-function studies aimed at assessing the physiological relevance of NgR-mediated protein-protein interactions to axon regeneration inhibition.

He, F. C., Q. Y. Fan, et al. (2003). "Long-term result of guided nerve regeneration with an inert microporous polytetrafluoroethylene conduit." Chin J Traumatol 6(3): 145-51.
 OBJECTIVE: To evaluate the long-term outcome of Polytetrafluoroethylene (PTFE) conduit in nerve repair and to provide more evidence in view of its potential application to achieve a satisfactory functional recovery in clinical settings. METHODS: Thirty-six Wistar rats had their right sciatic nerve transected and were repaired with either conventional microsuture technique (Control group, n=18) or a PTFE conduit with a gap of 5 mm left between the nerve stumps (PTFE group, n=18). At 6 and 9 months after the operation, electrophysiological assessment and measurement of gastrocnemius muscle weight were conducted and morphology of the regenerated nerves were studied with image analysis. RESULTS: At 6 months postoperatively, the nerve conduction velocity recovered to 60.86% and 54.36% (P<0.05), and the gastrocnemius muscle weight recovered to 50.89% and 46.11% (P>0.05) in the Control group and the PTFE group respectively. At 9 months postoperatively, the recovery rate was 65.99% and 58.79% for NCV (P>0.05), and 52.56% and 47.89% for gastrocnemius muscle weight (P>0.05) in the Control group and the PTFE group respectively. Regenerated nerve fibers in the PTFE group had a regular round shape with no fragmentation, wrinkling or splitting of the myelin sheath. Image analysis revealed that the ratio of the myelin area to the total fiber area was larger at 9 months than at 6 months in both groups (P<<0.01). CONCLUSIONS: Microporous PTFE conduit may be an alternative for nerve repair allowing of guided nerve regeneration and functional recovery with no obvious adverse effect at long-term.

Helfand, B. T., M. G. Mendez, et al. (2003). "A role for intermediate filaments in determining and maintaining the shape of nerve cells." Mol Biol Cell 14(12): 5069-81.
 To date, the functions of most neural intermediate filament (IF) proteins have remained elusive. Peripherin is a type III intermediate filament (IF) protein that is expressed in developing and in differentiated neurons of the peripheral and enteric nervous systems. It is also the major IF protein expressed in PC12 cells, a widely used model for studies of peripheral neurons. Dramatic increases in peripherin expression have been shown to coincide with the initiation and outgrowth of axons during development and regeneration, suggesting that peripherin plays an important role in axon formation. Recently, small interfering RNAs (siRNA) have provided efficient ways to deplete specific proteins within mammalian cells. In this study, it has been found that peripherin-siRNA depletes peripherin and inhibits the initiation, extension, and maintenance of neurites in PC12 cells. Furthermore, the results of these experiments demonstrate that peripherin IF are critical determinants of the overall shape and architecture of neurons.

Higuchi, H., T. Yamashita, et al. (2003). "Functional inhibition of the p75 receptor using a small interfering RNA." Biochem Biophys Res Commun 301(3): 804-9.
 The neurotrophin receptor p75(NTR) mediates a wide variety of biological effects. Consistent with the function in controlling the survival and neurite formation, p75(NTR) is expressed during the developmental stages of the nervous system. Importantly, p75(NTR) is re-expressed in various pathological conditions and is suggested to contribute to the inhibition of neuronal regeneration and the death of the neurons. Here we develop a tool to knock down the expression of p75(NTR) by employing a small interfering RNA (siRNA). The siRNA for p75(NTR) effectively reduces the expression of endogenous p75(NTR) both in Schwann cells and dorsal root ganglion neurons in vitro. NGF-induced cell death in Schwann cells and the neurite retraction in DRG neurons induced by myelin-associated glycoprotein are attenuated by the siRNA. Inhibition of p75(NTR) in specific pathological conditions by the siRNA may provide a potential therapeutic agent.

Himanen, J. P. and D. B. Nikolov (2003). "Eph receptors and ephrins." Int J Biochem Cell Biol 35(2): 130-4.
 Eph receptors, the largest subfamily of receptor tyrosine kinases (RTKs), and their ephrin ligands are important mediators of cell-cell communication regulating cell attachment, shape, and mobility. Eph signaling is crucial for the development of many tissues and organs including the nervous and cardiovascular systems. Both Ephs and ephrins are membrane-bound and their interactions at sites of cell-cell contact initiate unique bi-directional signaling cascades where information is transduced in both the receptor- and the ligand-expressing cells. Recent studies summarized in this review reveal how the signaling process is triggered upon ligand-receptor binding via the formation of a 2:2 circular heterotetramer. This fixes the orientation of the participating molecules and facilitates phosphorylation of their cytoplasmic domains which then interact with downstream signaling factors. The elucidation of the structural details of Eph-ephrin recognition and binding should yield insight into the future development of novel therapeutic agents targeting cardiovascular function, nerve regeneration, and cancer.

Hiraiwa, K. (2003). "[Novel findings from an animal tourniquet shock model]." Nippon Hoigaku Zasshi 57(2): 125-34.
 This article is a review of our experimental results regarding the physiological statuses and roles of chemical mediators in tourniquet shock, and a novel phenomenon, modulation reflex, that is commonly observed in this shock model is discussed. In a rabbit with a tourniquet applied to a hind limb for 24 hrs, blood pressure (BP) gradually falls after release of the tourniquet, but the decline in BP stops when a tourniquet is again applied to the hind limb, indicating that shock mediators are attributed to the hind limb. The levels of dipeptides (anserine and carnosine) and lysosomes in blood samples as well as the levels of leukotrienes (LTD4 and LTE4) in blood and muscle samples from rabbits in tourniquet shock were elevated. However, injection of a large amount of a dipeptide into an ear vein of a rabbit did not reduce BP, suggesting that both peptides may not be directly related with reduction in BP of rabbits in tourniquet shock. Injection of a platelet-activating factor (PAF) antagonist into an ear vein resulted in slight elevation of BP and the elevated level was maintained for about 1 to 4 hrs during the period of decline in BP in tourniquet shock. As for interleukin-6 (IL-6), IL-6-deficient mice at young ages have a significantly greater blood volume than do wild-type mice without concomitant changes in body composition. Therefore, the role for IL-6 in the regulation of peripheral circulation may be to elevate, not reduce BP. In mice in tourniquet shock, superoxide (O2-) production is observed in skeletal muscle cells and these cells correspond to mitochondria-rich cells. However, RT-PCR of muscle samples showed no significant nitric oxide synthase (NOS) mRNA expression after tourniquet release. Pretreatment with NOS inhibitors before tourniquet release reduced O2- production in the skeletal muscle. These results indicate that O2- produced in muscle subjected to ischemia/repefusion may be involved in shock. As for changes in mRNA expression patterns of pro-inflammatory cytokines and nerve growth factors in blood samples from rats in tourniquet shock, up-regulation of M-CSF mRNA began at 2 h after tourniquet application and was short-lived. The level of ATF-3 mRNA had increased at 1 h and NGF mRNA gradually increased and reached a significantly high level at 4 h after tourniquet application. These results indicate that the transient mRNA expressions probably trigger secondary events that may be beneficial to wound repair and regeneration. In the early stage of tourniquet shock, the levels of IL-6 mRNA in the liver and kidneys of rats increased progressively and significantly, and the levels of iNOS mRNA in the kidneys increased. These findings suggest that that humoral and/or cellular mediators produced locally in the hind limb are responsible for remote organ injuries. Thus, these mediators, interacting each other, may contribute to the progress of shock. We have also found a novel phenomenon in tourniquet shock using rabbits. When a tourniquet is applied to the upper hind limb of a rabbit for 24 hrs, and pressure is applied to the femoral medial area immediately after tourniquet release, a reflex of decrease in blood pressure and decrease in heart rate, which last for a short period, is usually observed. This reflex is mediated through the ipsilateral femoral nerves, central nervous system and vagal nerves. Since the modulation reflex may be due to peripheral nerve injury, we investigated morphological and molecular changes in sciatic nerves and dorsal root ganglion (DRG) neurons in rats after tourniquet application. At 4 hr after tourniquet application, light microscopic examination showed only degeneration of the tourniquet segment in the sciatic nerve but no morphological changes in the DRG, while electron microscopic examination revealed mitochondrial swelling in some DRG neurons on the tourniquet-applied side and calcium deposition in these swollen mitochondria. These findings suggest that peripheral nerve injury induced a large amount of calcium influx into neuronal cell somas and that excess amounts of calcium-influx into neurons resulted in mitochondial swelling. Results of mRNA level analyses showed NGF mRNA expression followed by NGF protein expression in Schwann cells of the ipsilateral DRGs at 4 h after tourniquet application but not in the contralateral or control DRGs. Similarly, significantly high nNOS and iNOS mRNA levels were observed in the ipsilateral DRGs at 4 h, and expressions of nNOS and iNOS proteins were detected in the ganglion of the ipsilateral DRG. In addition, the TNF-alpha mRNA levels were significantly increased in the ipsilateral DRGs at 1 h after tourniquet application, indicating that TNF-alpha was activated in the early stage of nerve injury and then induced iNOS mRNA expression. Large amounts of nitric oxide (NO) produced by iNOS might result in damage to the host cells, and an overdose of NO might induce apoptosis and eliminate damaged cells during the early stage of nerve injury.

Hirakawa, H., S. Okajima, et al. (2003). "Loss and recovery of the blood-nerve barrier in the rat sciatic nerve after crush injury are associated with expression of intercellular junctional proteins." Exp Cell Res 284(2): 196-210.
 The blood-nerve barrier in peripheral nerves is important for maintaining the environment for axons. Breakdown of the barrier by nerve injury causes various pathologies. We hypothesized that the breakdown and recovery of the blood-nerve barrier after injury are associated with the changes in the expression of intercellular junctional proteins. To test this hypothesis, we induced crush injuries in the rat sciatic nerve by ligation and analyzed spatiotemporal changes of claudin-1, claudin-5, occludin, VE-cadherin, and connexin43 by immunoconfocal microscopy and morphometry and compared them with changes in the permeability of the blood-nerve barrier by intravenous and local administration of Evans blue-albumin (EBA). On day 1 after removal of the ligature EBA leaked into the connective tissue in the endoneurium and then the leakage gradually decreased and disappeared on day 7. On day 1 claudin-1, claudin-5, occludin, VE-cadherin, and connexin43 had totally disappeared from the perineurium and endoneurium. Thereafter, claudin-1, claudin-5, occludin, and VE-cadherin recovered from day 2, whereas connexin43 was redetected on day 5. These results indicate that the breakdown and following recovery of the blood-nerve barrier are closely associated with changes in the expression of claudins, occludin, VE-cadherin, and connexin43 and that the recovery time course is similar but nonidentical.

Hiroi, S., Y. Tsukamoto, et al. (2003). "Involvement of gicerin, a cell adhesion molecule, in development and regeneration of chick sciatic nerve." FEBS Lett 554(3): 311-4.
 We have examined the role of gicerin, an immunoglobulin superfamily cell adhesion molecule, in chick sciatic nerves during development and regeneration. Gicerin was expressed in the spinal cord, dorsal root ganglion (DRG) and sciatic nerves in embryos, but declined after hatching. Neurite extensions from explant cultures of the DRG were promoted on gicerin's ligands, which were inhibited by an anti-gicerin antibody. Furthermore, gicerin expression was upregulated in the regenerating sciatic nerves, DRG and dorsal horn of the spinal cord after injury to the sciatic nerve. These results indicate that gicerin might participate in the development and regeneration of sciatic nerves.

Hirata, K., J. He, et al. (2003). "HSP27 is markedly induced in Schwann cell columns and associated regenerating axons." Glia 42(1): 1-11.
 It is well known that regenerating axons enter Schwann cell (SC) columns, within which they grow to reinnervate the appropriate targets. The current study detected a marked induction of a 27-kDa heat shock protein (HSP27) in the SC columns of crush-injured rat sciatic nerves. Immunohistochemical studies showed the first appearance of strong HSP27-immunoreactive linear structures in the proximal stump near an injury site 7 h after an operation. The HSP27-immunoreactive linear structures crossed the injury site to the distal stump 2 days after the operation. They then extended in a more proximal and more distal direction and were found to have propagated through the entire length of the nerve 1 week after the operation. This pattern of expression was maintained until 3 weeks after the operation. Double-immunofluorescent labeling and confocal laser microscopy confirmed that the linear structures consisted of SC columns and associated multiple axons. The HSP27-immunoreactive SC columns expressed glial fibrillary acidic protein, but not S-100 protein. Electron microscopy and immunoelectron microscopy demonstrated that reactive Schwann cells (SCs) and the associated axons with an outgrowing profile exhibited a strong immunoreactivity to HSP27, with the former containing a greater number of bundles of intermediate filaments. It is suggested that HSP27 may play an essential role in axonal outgrowth, especially by contributing to cytoskeletal dynamics in SCs.

Hofsaess, U. and J. P. Kapfhammer (2003). "Identification of numerous genes differentially expressed in rat brain during postnatal development by suppression subtractive hybridization and expression analysis of the novel rat gene rMMS2." Brain Res Mol Brain Res 113(1-2): 13-27.
 During postnatal development the potential for axonal growth and regeneration in the central nervous system (CNS) becomes very restricted. This decline of axon growth and regeneration might be due to developmental alterations in the expression level of genes which are strongly expressed in differentiating neurons during formation of axons, but which are downregulated later in development. In order to identify genes which are downregulated in rat brain with the completion of neuronal differentiation, we performed suppression subtractive hybridization (SSH) with rat cerebellum at two developmental stages. Several differentially expressed genes were identified. We present the detailed expression analysis of one of these, rMMS2, which is the rat homologue of mouse ubiquitin-conjugating enzyme-like protein MMS2 and belongs to a family of ubiquitin-conjugating enzyme variants (UEVs) that are highly similar to ubiquitin-conjugating enzymes E2 (Ubcs) but lack the essential amino acid residue in the active site. UEVs play a role in DNA repair and are possibly involved in ubiquitination, which may be important for the assembly and function of neuronal circuits. In the present study, we examined the temporal and spatial expression of rMMS2 transcript and show a strong developmental downregulation in rat brain by Northern blot analysis and in situ hybridization. The mRNA of rMMS2 is widely distributed in rat brain at late embryonic development but is differentially regulated during postnatal development; its expression is strongly reduced during maturation of the CNS. Our results show that SSH is a suitable method for identifying genes which are regulated during postnatal development and suggest that the newly identified rat UEV rMMS2 may play a role in neuronal development and differentiation.

Holmes, M., D. Maysinger, et al. (2003). "Neotrofin, a novel purine that induces NGF-dependent nociceptive nerve sprouting but not hyperalgesia in adult rat skin." Mol Cell Neurosci 24(3): 568-80.
 We report peripheral actions in rats of Neotrofin, a purine derivative of therapeutic interest. Systemic injections mimicked NGF in eliciting sprouting of nociceptive nerves without affecting their regeneration. The sprouting was prevented by anti-NGF treatment, implicating endogenous NGF. We detected no Neotrofin-induced increases in cutaneous NGF levels or in retrograde NGF transport. In contrast, both NGF and phosphorylation of trkA increased significantly in DRGs, with a marginal appearance of phosphorylated trkA in axons. We conclude that the DRG effects of Neotrofin are responsible for its induction of sprouting. Neotrofin also induced a striking phosphorylation of axonal erk 1 and 2, which was, however, unaffected by anti-NGF treatment. We suggest that this NGF-independent MAP kinase activation is involved in nonsprouting functions of Neotrofin such as neuroprotection. Unlike injected NGF, Neotrofin did not induce hyperalgesia, supporting its candidacy as a treatment for peripheral neuropathies like those induced by diabetes and anticancer chemotherapy.

Houle, J. D. and A. Tessler (2003). "Repair of chronic spinal cord injury." Exp Neurol 182(2): 247-60.
 Advances in medical and rehabilitative care now allow the 10-12,000 individuals who suffer spinal cord injuries each year in the United States to lead productive lives of nearly normal life expectancy, so that the numbers of those with chronic injuries will approximate 300,000 at the end of the next decade. This signals an urgent need for new treatments that will improve repair and recovery after longstanding injuries. In the present report we consider the characteristics of the chronically injured spinal cord that make it an even more challenging setting in which to elicit regeneration than the acutely injured spinal cord and review the treatments that have been designed to enhance axon growth. When applied in the first 2 weeks after experimental spinal cord injury, transplants, usually in combination with supplementary neurotrophic factors, and possibly modifications of the inhibitory central nervous system environment, have produced limited long-distance axon regeneration and behavioral recovery. When applied to injuries older than 4 weeks, the same treatments have almost invariably failed to overcome the obstacles posed by the neurons' diminished capacity for regeneration and by the increasing hostility to growth of the terrain at and beyond the injury site. Novel treatments that have stimulated regeneration after acute injuries have not yet been applied to chronic injuries. A therapeutic strategy that combines rehabilitation training and pharmacological modulation of neurotransmitters appears to be a particularly promising approach to increasing recovery after longstanding injury. Identifying patients with no hope of useful recovery in the early days after injury will allow these treatments to be administered as early as possible.

Hsieh, P. S., D. J. Bochinski, et al. (2003). "The effect of vascular endothelial growth factor and brain-derived neurotrophic factor on cavernosal nerve regeneration in a nerve-crush rat model." BJU Int 92(4): 470-5.
 OBJECTIVE: To test the hypothesis that an intracavernosal injection with brain-derived neurotrophin factor (BDNF) and vascular endothelial growth factor (VEGF) can facilitate nerve regeneration and recovery of erectile function after cavernosal nerve injury. MATERIALS AND METHODS: The study included 25 Sprague-Dawley rats; four had a sham operation, seven bilateral nerve crushing with no further intervention, and 14 bilateral nerve crushing with either an immediate (seven) or delayed for 1 month (seven) intracavernosal injection with BDNF+VEGF. Erectile function was assessed by cavernosal nerve electrostimulation at 3 months, and neural regeneration by NADPH-diaphorase staining and tyrosine hydroxylase (TH) staining of penile tissue and major pelvic ganglia (MPG). RESULTS: After nerve crushing, the functional evaluation at 3 months showed a lower mean (SD) intracavernosal pressure (ICP) with cavernosal nerve stimulation, at 33.9 (15.3) cmH2O, than in the sham group, at 107.8 (18.1) cmH2O. With an immediate injection with BDNF+VEGF the ICP was significantly higher than in the controls, at 67.8 (38.5) cmH2O. Even delayed injection with BDNF+VEGF improved the ICP, to 78.0 (21.8) cmH2O. Histological analysis of specimens stained for NADPH and TH showed a significant change in the morphology of terminal branches of the cavernosal and dorsal nerves, and the staining quality of the neurones in the MPG. The number of positively stained nerve fibres tended to revert to normal after treatment with BDNF+VEGF. CONCLUSION: An intracavernosal injection with BDNF+VEGF appears to both prevent degeneration and facilitate regeneration of neurones containing neuronal nitric oxide synthase in the MPG, dorsal nerve and intracavernosal tissue. Therefore it might have therapeutic potential for enhancing the recovery of erectile function after radical pelvic surgery.

Hu, Q. L., Y. J. Piao, et al. (2003). "[Expression and distribution of NGF and p75 during rabbit tibial nerve repair induced by human hair keratin conduits]." Di Yi Jun Yi Da Xue Xue Bao 23(9): 929-32.
 OBJECTIVE: To study the expression and distribution of nerve growth factor (NGF) and low-affinity neurophin receptor p75 during human hair keratin conduit-induced repair of rabbit tibial nerves. METHODS: Rabbit tibial nerves were transected and connected by either routine suture or by conduits made of human hair keratin (HHK), and after different time periods, paraffin-embedded sections of the nerve tissue at the damaged sites and the adjacent tissues, with normal rabbit tibial nerve sections as control, were prepared for immunohistochemistry. RESULTS: No positive NGF staining was observed in normal tibial nerve tissues, but 76 days after the surgery, strong NGF positivity was detected in the newly generated nerve tissue around the HHK implants until 100 days after the surgery, which was absent in the tissues around the suture. As for p75, there was no positive staining observed in normal tibial nerve tissue. Light positive p75 staining was found in the mature nerve tissues around the HHK implants, where the newly generated tissues were strongly p75-positive during the period between 76-and loo-days after surgery. CONCLUSIONS: HHK and its degenerative product, but not routine suture, can induce the production of NGF and p75 to create a favorable micro-environment for nerve regeneration. More NGF and p75 are produced in newly generated neurons than in mature ones.

Hu, J., S. Zou, et al. (2003). "Response of Schwann cells in the inferior alveolar nerve to distraction osteogenesis: an ultrastructural and immunohistochemical study." Int J Oral Maxillofac Surg 32(3): 318-24.
 The biological mechanisms of nerve adaptation to distraction osteogenesis have not yet been elucidated. This study observed response of Schwann cells in the inferior alveolar nerve (IAN) following mandibular lengthening by electron microscopy and immunohistochemistry of S-100 protein, a specific marker of Schwann cells. Unilateral mandibular distraction (10mm elongation) was performed in nine young adult goats. Three animals were sacrificed at 7, 14 and 28 days after completion of distraction, respectively. The distracted IAN specimens and control nerves (from the contralateral sides) were harvested and processed for histological, ultrastructural and immunohistochemical examinations. Wallerian degeneration was observed in the distracted IAN, and Signs of axonal regeneration, as well as many activated Schwann cells were seen in the lengthened nerves. The expression of S-100 protein increased significantly at early stage of distraction osteogenesis, but almost returned to the normal level at 28 days after distraction. This study suggests that Wallerian degeneration caused by mechanical stretching may stimulate Schwann cells to enter a proliferated and activated state. Schwann cells and S-100 protein appear to play crucial roles in axonal regeneration that contributes to nerve adaptation to gradual distraction. Therefore, the IAN injury caused by mandibular gradual distraction was not serious; it seems to recover totally through a complicated repair mechanism.

Hua, J., V. P. Kumar, et al. (2003). "Microscopic changes at the neuromuscular junction in free muscle transfer." Clin Orthop(411): 325-33.
 Free muscle transfers do not generate the same force after transfer as that at the original sites. Light and electron microscopy were used to study serially during 30 weeks the changes at the neuromuscular junction after free muscle transfer of the gracilis muscle in the adult Wistar rat. Under light microscopy, after staining with acetylthiocholine the neuromuscular junction showed changes of degeneration with withdrawal of the innervating axon terminal followed by regeneration and reconstitution of the neuromuscular junction. The newly formed neuromuscular junction still lacked the structural detail seen in the control neuromuscular junction, even after 30 weeks. With the electron microscope, mitochondrial swelling and clumping of the synaptic vesicles were followed by withdrawal of the axon terminal from the muscle membrane on denervation. The infolding of the muscle membrane at the neuromuscular junction became less prominent. With reinnervation the ultrastructure of the junction was only partially reestablished with poorly reconstituted primary and secondary folds of the muscle membrane 30 weeks after the transfer. Failure of complete reformation of the ultrastructure of the neuromuscular junction may provide another explanation for failure of full recovery of skeletal muscle function after free muscle transfer.

Huang, M. C., K. C. Chen, et al. (2003). "Cervical root repair in adult rats after transection: recovery of forelimb motor function." Exp Neurol 180(2): 101-9.
 Functional recovery was achieved in rats after repairing the transected left sixth and seventh cervical roots. Intercostal nerves were used for reanastomosis between the transected roots and the spinal cord, and acidic fibroblast growth factor with fibrin glue was applied. Experimental rats showed relevant functional recovery of gait and grooming reflexes. Electromyography demonstrated less denervation and more regeneration. Horseradish peroxidase retrograde axonal tracing disclosed a statistically significant increase of motor neuron survival, suggesting that motor neuron survival was significantly correlated with functional recovery. It is our belief that this novel treatment strategy may help patients with similar injuries in the future.

Huang, X., D. Y. Wu, et al. (2003). "Support of retinal ganglion cell survival and axon regeneration by lithium through a Bcl-2-dependent mechanism." Invest Ophthalmol Vis Sci 44(1): 347-54.
 PURPOSE: To explore whether lithium, a long-standing mood-stabilizing drug, can be used to induce expression of Bcl-2 and support the survival and regeneration of axons of retinal ganglion cells (RGCs). METHODS: Levels of expression of Bcl-2 in the retina were assessed with quantitative reverse transcription-polymerase chain reaction. To determine whether lithium directly supports the survival of and axon-regenerative functions of RGCs, various amounts of lithium were added to cultures of isolated RGCs. Anti-Thy1.2 antibodies-conjugated to magnetic beads were used to isolate the RGCs. In addition, retina-brain slice cocultures were prepared from tissues of Bcl-2-deficient or Bcl-2-transgenic mice and treated with various amounts of lithium. The effects of the expression of Bcl-2 on lithium-mediated functions were then analyzed. RESULTS: Normal mouse retina expressed very low levels of Bcl-2 after birth. Addition of lithium in the culture increased mRNA levels of Bcl-2 in retinas of postnatal mice in a dose-dependent manner. Moreover, lithium promoted not only the survival of RGCs but also the regeneration of their axons. Depleting or forcing the expression of Bcl-2 in RGCs eliminated the effects of lithium. CONCLUSIONS: Lithium supports both the survival and regeneration of RGC axons through a Bcl-2-dependent mechanism. This suggests that lithium may be used to treat glaucoma, optic nerve neuritis, the degeneration of RGCs and their nerve fibers, and other brain and spinal cord disorders involving nerve damage and neuronal cell loss. To achieve full regeneration of the severed optic nerve, it may be essential to combine lithium therapy with other drugs that mediate induction of a permissive environment in the mature central nervous system.

Iannotti, C., H. Li, et al. (2003). "Glial cell line-derived neurotrophic factor-enriched bridging transplants promote propriospinal axonal regeneration and enhance myelination after spinal cord injury." Exp Neurol 183(2): 379-93.
 Glial cell line-derived neurotrophic factor (GDNF), a distant member of the transforming growth factor-beta (TGF-beta) family, is widely expressed in the developing and adult central nervous system (CNS). At present, limited information is available regarding the effects of GDNF in the repair of spinal cord injury (SCI). In the present study, mini-guidance channels containing either: (1) Matrigel (MG, a basement membrane component), (2) Schwann cells (SCs, 120 x 10(6)/ml) in MG (SC-MG), (3) recombinant human GDNF (rhGDNF, 3 microg/microl) in MG (GDNF-MG), and (4) a combination of all three components (GDNF-SC-MG) were grafted into a T9 hemisection-gap lesion in adult rats to examine the effects of GDNF on axonal regeneration and myelination following SCI. Thirty days post-transplantation, limited axonal growth was observed within guidance channels containing MG-alone (MG). When SCs were added to the channels (SC-MG group), consistent axonal ingrowth containing both myelinated and unmyelinated axons was observed, confirming our previous findings. The addition of GDNF-alone without SCs (GDNF-MG) resulted in substantial ingrowth of unmyelinated axons, suggesting that GDNF has a direct neurite-growth promoting effect on these axons. Implantation of channels containing both GDNF and SCs (GDNF-SC-MG) produced a significant and synergistic increase in axonal regeneration and myelination. In addition, GDNF reduced the extent of reactive gliosis, infiltration of activated macrophages/microglia, and cystic cavitation at the graft-host interfaces. Retrograde tracing revealed that grafts of SC-seeded channels containing GDNF promoted a significant increase in the number of propriospinal neurons which had regenerated their axons into the grafts, as compared to SC-MG-seeded channels. These results indicate that GDNF may play a novel therapeutic role in promoting propriospinal axonal regeneration, enhancing myelin formation, and improving graft-host interfaces after SCI.

Iijima, K., F. Harada, et al. (2003). "Temporal expression of immunoreactivity for heat shock protein 25 (Hsp25) in the rat periodontal ligament following transection of the inferior alveolar nerve." Brain Res 979(1-2): 146-52.
 The present study examined the immunohistochemical localization of heat shock protein 25 (Hsp25) during the regeneration of nerve fibers and Schwann cells in the periodontal ligament of the rat lower incisor following transection of the inferior alveolar nerve. In the untreated control group, the periodontal ligament of rat incisor did not contain any Hsp25-immunoreaction. On postoperative day 3 (PO 3d), a small number of Schwann cells with slender cytoplasmic processes exhibited Hsp25-immunoreactivity. From PO 5d to PO 21d, Hsp25-positive nerve fibers and Schwann cells drastically increased in number in the alveolar half of the ligament. Although the axons of some regenerating Ruffini-like endings also showed Hsp25-immunoreactions, the migrated Schwann cells were devoid of Hsp25-immunoreaction. Thereafter, Hsp25-positive structures decreased in number gradually to disappear from the periodontal ligament by PO 56d. This temporal expression of Hsp25 in the periodontal ligament well-reflected the regeneration process of the nerve fibers. Hsp25 in the regenerating nerve fibers and denervated Schwann cells most likely serves in modulating actin dynamics and as a cellular inhibitor of apoptosis, respectively.

Ikeguchi, R., R. Kakinoki, et al. (2003). "Rat nerve regeneration through a silicone chamber implanted with negative carbon ions." Brain Res Dev Brain Res 140(1): 127-31.
 We investigated whether a tube with its inner surface implanted with negatively-charged carbon ions (C(-) ions) would enable axons to extend over a distance greater than 10 mm. The tube was found to support nerves regenerating across a 15-mm-long inter-stump gap. Silicone treated with C(-) ions showed increased hydrophilic properties and cellular affinity, and axon regeneration was promoted with this increased biocompatibility.

Imai, T., Y. Atsumi, et al. (2003). "Regeneration of periodontal Ruffini endings of rat lower incisors following nerve cross-anastomosis with mental nerve." Brain Res 992(1): 20-9.
 The present study utilized protein gene product 9.5 (PGP 9.5) and S-100 protein immunohistochemistry to examine if Ruffini endings, the primary mechanoreceptors in periodontal ligaments, can regenerate following nerve cross-anastomosis with an inappropriate nerve. Normally, axon terminals of periodontal Ruffini endings are extensively ramified, and terminal Schwann cells, identified by their S-100 immunoreactivity, are associated with axon terminals. Schwann cells are restricted to the alveolus-related part (ARP), but not tooth-related part (TRP) or the shear zone at the border between the ARP and the TRP of the lingual periodontal ligament of the lower incisor. When the central portion of the mental nerve (MN) was connected with the peripheral portion of the inferior alveolar nerve (IAN), regenerating MN fibers invaded the IAN around postoperative day 5 (PO 5). During the postoperative period, numerous S-100-immunoreactive (IR) cells, presumably terminal Schwann cells, began to migrate to the shear zone and the TRP. PGP 9.5-IR elements reappeared at PO 7 and gradually increased in number. Around PO 28, the terminal portion of the regenerating Ruffini endings appeared dendritic, but less expanded, and the rearrangement of terminal Schwann cells was noted. Regenerated periodontal Ruffini endings were slightly smaller in number. The number of trigeminal ganglion neurons sending peripheral processes beyond the site of injury was smaller compared to those of normal MN, but their cross-sectional areas were almost comparable. Expressions of calbindin D28k and calretinin, normally localized in axonal elements in Ruffini endings, were first detected around PO 56. The present results show that parts of periodontal Ruffini endings can regenerate following nerve cross-anastomosis with mental nerve.

Imitola, J., E. Y. Snyder, et al. (2003). "Genetic programs and responses of neural stem/progenitor cells during demyelination: potential insights into repair mechanisms in multiple sclerosis." Physiol Genomics 14(3): 171-97.
 In recent years, it has become evident that the adult mammalian CNS contains a population of neural stem cells (NSCs) described as immature, undifferentiated, multipotent cells, that may be called upon for repair in neurodegenerative and demyelinating diseases. NSCs may give rise to oligodendrocyte progenitor cells (OPCs) and other myelinating cells. This article reviews recent progress in elucidating the genetic programs and dynamics of NSC and OPC proliferation, differentiation, and apoptosis, including the response to demyelination. Emerging knowledge of the molecules that may be involved in such responses may help in the design of future stem cell-based treatment of demyelinating diseases such as multiple sclerosis.

Inman, D. M. and O. Steward (2003). "Ascending sensory, but not other long-tract axons, regenerate into the connective tissue matrix that forms at the site of a spinal cord injury in mice." J Comp Neurol 462(4): 431-49.
 Mice exhibit a unique wound healing response following spinal cord injury in which the lesion site fills in with a connective tissue matrix. Previous studies have revealed that axons grow into this matrix, but the source of the axons remained unknown. The present study assesses whether any of these axons were the result of long tract regeneration. C57Bl/6 mice received crush injuries and were allowed to survive for 6 weeks to 7 months. Biotinylated dextran amine (BDA) was injected into the somato-motor cortex to trace descending corticospinal tract (CST) axons, into the midbrain to label descending brainstem pathways including the rubrospinal and reticulospinal tracts, or into the L5 dorsal root ganglion to trace ascending projections of first-order sensory neurons. Spinal cords from other mice were prepared for immunocytochemistry using antibodies against neurofilament protein (NF), 5-HT to reveal descending serotonergic axons, calcitonin gene-related protein (CGRP) to reveal ascending sensory axons, and chondroitin sulfate proteoglycan (CSPG) to assess the distribution of molecules that are inhibitory to axon growth. NF immunostaining revealed axons in the connective tissue matrix at the lesion site, confirming previous studies that used protargol staining. CST axons did not enter the connective tissue matrix, but did sprout extensively in segments adjacent to the injury site. Rubrospinal and reticulospinal tract axons also did not grow into the lesion site. 5-HT-positive axons extended to the edge of the lesion, and a few axons followed astrocyte processes into the margins of the lesion site. In contrast to the other pathways, BDA-labeled ascending sensory axons did extend into and arborized extensively within the connective tissue matrix, although the subgroup of ascending axons that are positive for CGRP did not. These results indicate that the connective tissue matrix is permissive for regeneration of some classes of ascending sensory axons but not for other axonal systems.

Inoue, M., T. Hojo, et al. (2003). "The effects of electroacupuncture on peripheral nerve regeneration in rats." Acupunct Med 21(1-2): 9-17.
 This study was designed to examine the effects of electroacupuncture with direct current (DC) on peripheral nerve regeneration. The left sciatic nerve of 55 7-month-old rats was crushed at the thigh. They were ramdomly allocated to four groups: distal cathode DC group (n = 15), distal anode DC group (n = 14), sham operated group (n = 13), and control group (n = 13). In the distal cathode DC group, a cathode electrode was connected to an insulated acupuncture needle inserted at 1 cm distal to the injured site, while an anode electrode was connected to a needle inserted at 1 cm proximal to the lesion. In the distal anode DC group, the anode and the cathode electrode were connected to the needle at 1 cm distal and proximal to the lesion respectively. In the sham operated group, no electrical stimulation was given to the insulated needle inserted at the same site, and in the control group, no treatment was given. Regeneration of the sciatic nerve was evaluated by the number of evoked EMGs recorded at 12 sites in the plantar region, by their latency, and by the weight ratio of the tibialis anterior at four weeks after the crush injury. Regeneration of the peripheral nerve was faster and more accelerated in the distal cathode DC group than in the other groups, while in the distal anode DC group the regeneration was delayed. This result suggested electroacupuncture with cathode distal orientation might be a useful treatment having the advantage of enabling deeper insertion with minimal tissue damage.

Iseda, T., T. Nishio, et al. (2003). "Spontaneous regeneration of the corticospinal tract after transection in young rats: collagen type IV deposition and astrocytic scar in the lesion site are not the cause but the effect of failure of regeneration." J Comp Neurol 464(3): 343-55.
 In young rats the corticospinal tract regenerated after a single transection of the spinal cord with a sharp blade, but regeneration failed if the transection was repeated to make a more traumatic injury. To identify cells and associated molecules that promote or impede regeneration, we compared expression of collagen type IV, glial fibrillary acidic protein (GFAP), and vimentin immunoreactivity (IR) at the lesion sites in combination with anterograde axonal tracing between animals with two types of transection. Axonal regeneration occurred as early as 18 hours after transection; regenerating axons penetrated vessel-like structures with collagen type IV-IR at the lesion site, while reactive astrocytes coexpressing GFAP- and vimentin-IR appeared in the lesioned white matter. In contrast, when regeneration failed astrocytes were absent near the lesion. By 7 days sheet-like structures with collagen type IV-IR and astrocytic scar appeared in the lesioned white matter and persisted until the end of the observation period (31 days). On the basis of their spatiotemporal appearance, collagen type IV-IR sheet-like structures and the astrocytic scar follow, rather than cause, the failure of regeneration. The major sign, and perhaps cause, of failure of axonal regeneration is likely the prolonged disappearance of astrocytes around the lesion site in the early postinjury period.

Isacson, O., L. M. Bjorklund, et al. (2003). "Toward full restoration of synaptic and terminal function of the dopaminergic system in Parkinson's disease by stem cells." Ann Neurol 53 Suppl 3: S135-46; discussion S146-8.
 New therapeutic nonpharmacological methodology in Parkinson's disease (PD) involves cell and synaptic renewal or replacement to restore function of neuronal systems, including the dopaminergic (DA) system. Using fetal DA cell therapy in PD patients and laboratory models, it has been demonstrated that functional motor deficits associated with parkinsonism can be reduced. Similar results have been observed in animal models with stem cell-derived DA neurons. Evidence obtained from transplanted PD patients further shows that the underlying disease process does not destroy transplanted fetal DA cells, although degeneration of the host nigrostriatal system continues. The optimal DA cell regeneration system would reconstitute a normal neuronal network capable of restoring feedback-controlled release of DA in the nigrostriatal system. The success of cell therapy for PD is limited by access to preparation and development of highly specialized dopaminergic neurons found in the A9 and A10 region of the substantia nigra pars compacta as well as the technical and surgical steps associated with the transplantation procedure. Recent laboratory work has focused on using stem cells as a starting point for deriving the optimal DA cells to restore the nigrostriatal system. Ultimately, understanding the cell biological principles necessary for generating functional DA neurons can provide many new avenues for better treatment of patients with PD.

Ishino, T., M. Shirai, et al. (2003). "Identification of genes induced in regenerating Xenopus tadpole tails by using the differential display method." Dev Dyn 226(2): 317-25.
 To identify candidate gene(s) involved in the tail regeneration of Xenopus laevis tadpoles, we used the differential display method to isolate four genes (clones 1, 2, 13a, and 13b) whose expression is induced in regenerating tadpole tails. Among them, clones 13a and 13b were found to encode the Xenopus homologues of the alpha1 chain of type XVIII collagen and neuronal pentraxin I, respectively. Expression of clone 2 and neuronal pentraxin I genes increased dramatically in the blastema 3 days after amputation, whereas that for the clone 1 and type XVIII collagen genes was induced gradually after amputation. In situ hybridization revealed that the neuronal pentraxin I gene is expressed specifically in the regenerating tail epidermis but not in the normal tail epidermis or the most distal margin of the tail blastema, suggesting that it has a tissue-inductive role in tail regeneration. Expression of the four genes was induced in the limb and in the tail blastema, suggesting that they are involved in the regeneration of both organs. Finally, expression of clone 2 and neuronal pentraxin I genes was scarce during embryonic stages in comparison to the tail blastema, suggesting that their main functions are in organ regeneration. Our results demonstrate unique features of spatial and temporal gene expression patterns during Xenopus tadpole tail regeneration.

Islamov, R. R., V. Chintalgattu, et al. (2003). "Differential expression of endothelin receptors in regenerating spinal motor neurons in mice." Brain Res Mol Brain Res 116(1-2): 163-7.
 On day 4 after sciatic nerve crush injury, expression and localization of endothelin receptors ET(A) and ET(B) in the lumbar spinal cord were examined. Immunohistochemical staining with antibodies to ET(A) and ET(B) receptors showed cytoplasmic distribution of ET(A) receptors in motor neurons, whereas ET(B) receptors were localized in the perinuclear region. On the injured side of the lumbar spinal cord, when compared to contralateral, results demonstrated an up-regulation of ET(B) and a down-regulation of ET(A) receptors expression at the level of both mRNA and protein. These results suggest that ET(B) receptors may play a role in the regeneration of axotomized motor neurons.

Islamov, R. R., W. A. Hendricks, et al. (2003). "Effect of 17 beta-estradiol on gene expression in lumbar spinal cord following sciatic nerve crush injury in ovariectomized mice." Brain Res 966(1): 65-75.
 Previously, we observed that estrogen treatment enhances regeneration of the sciatic nerve after crush injury [Brain Res. 943 (2002) 283]. In this research, we studied expression of estrogen receptors and effects of estrogen on gene expression in the lumbar spinal cord, following sciatic nerve crush injury. Using the Atlas Mouse 1.2 Array, changes in the expression of 267 of 1176 genes were registered 4 days after nerve injury. Those genes that exhibited a change in signal intensity ratios of 2-fold or greater were selected as up-regulated (42) or down-regulated (21). In estrogen treated mice, we have observed up-regulation of the genes known to control apoptosis, cell proliferation, and growth, which might account for the positive effects of estrogen on the regeneration of motor neurons. Immunohistochemical staining revealed estrogen receptor-alpha and estrogen receptor-beta localized in the nucleus and cytoplasm of lumbar motor neurons, and in the regenerating neurites of the sciatic nerve. Expression of estrogen receptor-alpha and estrogen receptor-beta mRNA in lumbar spinal cord was shown by traditional RT-PCR. Using real-time quantitative RT-PCR, we demonstrated increased expression of estrogen receptors-alpha and -beta mRNA on the injured side of the lumbar spinal cord. Western blot analysis showed the accumulation of ERs in regenerating sciatic nerve, and revealed a 40% increase of activated ERK1/2 in estrogen treated mice, compared to placebo. Our findings indicate that: (i). axotomized motor neurons increase expression of estrogen receptors-alpha and -beta mRNA, (ii). estrogen mediates the expression of genes which accelerate the growth and maturation of axons, and (iii). estrogen receptors are transported from the perikaryon into regenerating neurites, and estrogen promotes regeneration locally through the non-genomic ERK-activated signaling pathway.

Ito, T., T. Nakamura, et al. (2003). "Biodegradation of polyglycolic acid-collagen composite tubes for nerve guide in the peritoneal cavity." Asaio J 49(4): 417-21.
 The rate of biodegradation of new types of polyglycolic acid (PGA)-collagen composite tubes for nerve regeneration was evaluated in the peritoneal cavity. PGA mesh tubes with a diameter of 2 or 4 mm were coated with collagen solution and dried at room temperature. The tubes were then subjected to dehydrothermal treatment (composite tube). A 2 mm PGA-collagen composite tube filled with collagen sponge was also investigated in this study (sponge tube). Tubes with a length of 15 mm were fixed at the parietal peritoneum of BALB/c mice and excised 2 weeks and 1, 2, and 3 months after the operation. The inner areas of the excised tubes were measured microscopically. Statistical analysis was performed by one way ANOVA and Fisher's PLSD test. Although the inner areas of the 2 and 4 mm composite tubes were not maintained 1 month after the operation (62 +/- 6.8% and 21 +/- 3.8%, respectively), they were well maintained in the sponge tubes (83 +/- 6.4%). The inner areas of the sponge tubes were significantly larger than those of the composite tubes until 2 months after surgery. These results suggest that sponge tubes are more suitable than composite tubes for nerve regeneration in the peritoneal cavity.

Ito, T., T. Nakamura, et al. (2003). "Regeneration of hypogastric nerve using a polyglycolic acid (PGA)-collagen nerve conduit filled with collagen sponge proved electrophysiologically in a canine model." Int J Artif Organs 26(3): 245-51.
 The hypogastric nerve (HGN) is a sympathetic nerve in the peritoneal cavity and controls urinary and seminal functions. In this study, the regeneration of HGN was determined by using a new type of an artificial nerve conduit, polyglycolic acid (PGA)-collagen nerve conduit filled with collagen sponge in two dogs. A PGA-collagen nerve conduit (diameter=2 mm) was interposed in a 10 mm gap of the right HGN. The regeneration of the HGN was evaluated electrophysiologically 8 months after the operation. The intraluminal pressure of spermatic duct and the bladder neck were elevated 80 mmHg and 25 mmHg respectively by the stimulation across the regenerated HGN. The prostate contraction was also elicited. The responses diminished after the excision of the regenerated portion of HGN. These results proved the regeneration of HGN and this nerve conduit will be great help for patients who suffer from urinary and seminal disturbances.

Ito, J. (2003). "[Regeneration of the auditory pathway]." Nippon Rinsho 61(3): 469-74.
 In order to investigate the possibility of the treatment of sensorineural hearing disturbance, experiments were performed using animals. First, the central cochlear pathway in the brain stem to pons was transected in adult rats. Tissue from embryos was transplanted to the lesion site. In 20% of the rats examined, the axons regrew beyond the transected site and regenerated into the denervated side and terminated at the normal targets. The hearing function of animals was also recovered. Those findings contradict the widely held view that the adult mammalian central auditory system cannot be restored following damage. Then, adult rat hippocampus-derived neural stem cells(NSC) were grafted into newborn rat cochlea. Within two to four weeks of grafting to the cochlea, some NSC survived in the cochlear cavity. Some of them had adopted the morphologies and positions of hair cells. This suggests that NSC can adapt to the environment of the cochlea and gives hope for treatment of the damaged cochlea and sensorineural hearing loss.

Itoh, S., I. Yamaguchi, et al. (2003). "Hydroxyapatite-coated tendon chitosan tubes with adsorbed laminin peptides facilitate nerve regeneration in vivo." Brain Res 993(1-2): 111-23.
 On the inner surface of tendon chitosan tubes having a triangular shape and a hydroxyapatite coating (t-chitosan/HAp tube), laminin-1 and laminin peptides (YIGSR, IKVAV) have been adsorbed in order to develop nerve growth conduits. The mechanical property, biocompatibility and efficacy of these tubes for nerve regeneration were examined. Step-1: bridge grafting (15 mm) into the sciatic nerve of Sprague-Dawley (SD) rats was carried out using either t-chitosan or t-chitosan/HAp tubes having either a circular or triangular cross section (N=12 in each group). Specimens were taken after 2-, 4-, 6- and 8-week post-implantation (N=3 in each group) for histology determinations. Step-2: t-chitosan/HAp tubes having a triangular cross section with adsorbed laminin-1, CDPGYIGSR or CSRARKQAASIKVAVSAD, as well as control tubes without pre-adsorption were used for implantation (N=18 in each group). Isografting was also carried out (N=6). Histological evaluation was carried out similarly as in Step-1. Furthermore, evoked muscle and sensory nerve action potentials were recorded, and the percentage of myelinated axon area measured at 10 mm distance of the distal anastomosed site in the experimental, control and isograft groups after 12 weeks (N=6 in each group). The results of histological findings, as well as mechanical properties, suggest that a triangular tube shape with a HAp coating benefits nerve regeneration. The effect of laminin peptides (YIGSR, followed by IKVAV) to enhance the growth of regenerating axons has been found comparable with intact laminin-1. Although histological regeneration in both the YIGSR- and laminin-1-treated t-chitosan/HAp tubes matches the isografts, the functional recovery is however delayed.

Jacobs, W. B. and M. G. Fehlings (2003). "The molecular basis of neural regeneration." Neurosurgery 53(4): 943-48; discussion 948-50.
 THE CENTRAL NERVOUS SYSTEM (CNS) is incapable of meaningful regeneration of lost neurons or axonal and dendritic connections after injury. This often results in permanent and severe loss of neurological function. The CNS regenerative process is unsuccessful for at least three reasons: neurons are highly susceptible to death after CNS injury; the CNS extracellular milieu contains multiple inhibitory factors that make it nonpermissive to growth; and the intrinsic growth capacity of postmitotic neurons is constitutively reduced. However, a number of recent developments in each of these areas is providing insight into the cellular mechanisms involved in CNS regeneration and may eventually lead to the development of therapies capable of effecting successful CNS regeneration.

Jang, W., S. L. Youngentob, et al. (2003). "Globose basal cells are required for reconstitution of olfactory epithelium after methyl bromide lesion." J Comp Neurol 460(1): 123-40.
 Despite a remarkable regenerative capacity, recovery of the mammalian olfactory epithelium can fail in severely injured areas, which subsequently reconstitute as aneuronal respiratory epithelium (metaplasia). We contrasted the cellular response of areas of the rat epithelium that recover as olfactory after methyl bromide lesion with those undergoing respiratory metaplasia in order to identify stem cells that restore lesioned epithelium as olfactory. Ventral olfactory epithelium is at particular risk for metaplasia after lesion and patches of it are rendered acellular by methyl bromide exposure. In contrast, globose basal cells (GBCs, marked by staining with GBC-2) are preserved in surrounding ventral areas and uniformly throughout dorsal epithelium, which consistently and completely recovers as olfactory after lesion. Over the next few days, neurons reappear, but only in those areas in which GBCs are preserved and multiply. In contrast, parts of the epithelium in which GBCs are destroyed are repopulated in part by Bowman's gland cells, which pile up above the basal lamina. Electron microscopy confirms the reciprocity between gland cells and globose basal cells. By 14 days after lesion, the areas that are undergoing metaplasia are repopulated by typical respiratory epithelial cells. As horizontal basal cells are eliminated from all parts of the ventral epithelium, the data suggest that GBC-2(+) cells are ultimately responsible for regenerating olfactory neuroepithelium. In contrast, GLA-13(+) cells may give rise to respiratory metaplastic epithelium where GBCs are eliminated. Thus, we support the idea that a subpopulation of GBCs is the neural stem cell of the olfactory epithelium.

Jasmin, L., A. Boudah, et al. (2003). "Long-term effects of decreased noradrenergic central nervous system innervation on pain behavior and opioid antinociception." J Comp Neurol 460(1): 38-55.
 Here we examine whether a permanent reduction in the noradrenergic (NA) innervation of the spinal cord leads to a chronic decreased nociceptive threshold. NA denervation of rats was achieved by intrathecal injection of dopamine beta-hydroxylase antibodies conjugated to the toxin saporin. A subset of animals also underwent unilateral L5 spinal nerve ligature to induce sustained neuropathic pain behavior. NA fibers and terminals were lost throughout the spinal cord 2 weeks after toxin application and were still absent 12 months later, indicating that regeneration did not occur. There was also a widespread loss of NA terminals in the cerebral cortex, whereas innervation of the hypothalamus and amygdala were close to normal and NA innervation of the brainstem was moderately reduced. There was extensive loss of NA cells in the locus coeruleus and A5 and A7 cell groups. Dopaminergic and serotoninergic innervation was normal. Intracerebroventricular injection of the toxin resulted in additional NA reduction in the hypothalamus, amygdala, and A1 and A2 cell groups. Long-term removal of NA afferents did not affect nociceptive thresholds. Neuropathic animals showed greater mechanical hyperalgesia in the affected hindpaw only during the first 60 days after toxin. Rats lacking NA spinal afferents were less responsive to the antinociceptive effects of morphine, especially in the neuropathic hindpaw, and did not display opioid-dependent stress analgesia. Finally, in the spinal cord of toxin-treated rats, immunoreactivity for substance P was decreased, whereas that of its receptor (NK1) was increased. These animals exhibited antinociception to a low dose of an NK1 receptor antagonist. Our results suggest that NA contributes only modestly to determining the nociceptive threshold and that its antinociceptive effects are closely linked to opioidergic and tachykinergic neurotransmission.

Jazayeri, M., M. R. Ghavanini, et al. (2003). "A study of the sympathetic skin response and sensory nerve action potential after median and ulnar nerve repair." Electromyogr Clin Neurophysiol 43(5): 277-9.
 The purpose of this study was to compare SSR with sensory nerve action potential (SNAP) responses in regeneration of injured peripheral nerves after nerve repair. We studied 10 male patients with a mean age of 26.7 years. All the patients had complete laceration of median or ulnar nerves. The patients were followed up at least for six months. SSR and SNAP assessment were performed every one to two months. Normal hands were used as controls. SSR was positive after 15.8 +/- 9.4 weeks (mean +/- 2 SD) and SNAP after 27.8 +/- 12.9 weeks (mean +/- 2 SD). The difference was statistically significant (P value < 0.001). This can be due to more rapid growth of sympathetic unmyelinated fibers relative to sensory myelinated fibers. This study also shows that recovery of the sudomotor activity following nerve repair is satisfactory in general and SSR can be used as a useful and sensitive method in the evaluation of sudomotor nerve regeneration.

Jean, I. and C. Fressinaud (2003). "Spontaneous central nervous system remyelination is not altered in NFH-lacZ transgenic mice after chemical demyelination." J Neurosci Res 73(1): 54-60.
 Harmonious functioning of the nervous system depends on neuron-glia interactions, particularly between the axons and their myelinating cells, i.e., oligodendrocytes (OL) in the central nervous system (CNS). In human demyelinating diseases such as multiple sclerosis (MS), demyelination may be associated with axonal damage, but alterations of the axonal cytoskeleton, which is composed mainly of neurofilaments (NF) and microtubules, are largely unknown, as are the consequences on remyelination. In a model of demyelination induced by lysophosphatidylcholine (LPC), we have shown that demyelination was correlated with a decrease in NF immunolabelling, and that these axonal abnormalities were reduced by platelet-derived growth factor (PDGF)-enhanced remyelination in adult rats. We have analysed the spontaneous remyelination after LPC stereotaxic injection in the CNS of transgenic NFH-lacZ mice, which present axonal atrophy caused by abnormal distribution of NF, associated with hypermyelination in the PNS, and normal myelin thickness in the CNS. Axonal atrophy in the CNS of NFH-lacZ mice was confirmed, but it was not worsened by demyelination. On the contrary, demyelination induced axonal atrophy in wild-type mice, demonstrating that NF are essential for axonal calibre determination. Moreover, an efficient spontaneous remyelination occurred in NFH-lacZ as well as in wild-type mice, indicating that the NF are not necessary for CNS remyelination. These findings point out that NF modifications observed in MS may not be responsible for the lack of remyelination in this disease.

Jean, I., C. Lavialle, et al. (2003). "Neurotrophin-3 specifically increases mature oligodendrocyte population and enhances remyelination after chemical demyelination of adult rat CNS." Brain Res 972(1-2): 110-8.
 In human central nervous system (CNS) demyelinating diseases, spontaneous remyelination is often incomplete. Therefore, we have tested whether neutrotrophin-3 (NT-3) accelerates CNS myelin repair after a chemically-induced demyelination. One group of adult rats was injected in the corpus callosum (CC) with 1 microl of 1% lysophosphatidylcholine (LPC) and 1 microl of NT-3 (1 microg/microl), and 15 days after injury (D15) remyelination was compared to control rats (receiving 1 microl of LPC+1 microl of vehicle buffer of NT-3). The demyelinated volume decreased by 56% in NT-3-treated rats at D15, and immunohistochemistry showed an increase in mature MBP(+) oligodendrocytes (OL) (+66%) in treated animals (whereas less mature (CNP(+)) OL were unchanged). Since less than 3% axons degenerate in this model, and as astrocytic gliosis was not modified, these data suggest that NT-3 acts directly on cells of the OL lineage to enhance remyelination in vivo.

Jejurikar, S. S. and W. M. Kuzon Jr (2003). "Satellite cell depletion in degenerative skeletal muscle." Apoptosis 8(6): 573-8.
 Adult skeletal muscle has the striking ability to repair and regenerate itself after injury. This would not be possible without satellite cells, a subpopulation of cells existing at the margin of the myofiber. Under most conditions, satellite cells are quiescent, but they are activated in response to trauma, enabling them to guide skeletal muscle regeneration. In degenerative skeletal muscle states, including motor nerve denervation, advanced age, atrophy secondary to deconditioning or immobilization, and Duchenne muscular dystrophy, satellite cell numbers and proliferative potential significantly decrease, contributing to a diminution of skeletal muscle's regenerative capacity and contractility. This review will highlight the fate of satellite cells in several degenerative conditions involving skeletal muscle, and will attempt to gauge the relative contributions of apoptosis, senescence, impaired proliferative potential, and host factors to satellite cell dysfunction.

Jiang, S., J. Wang, et al. (2003). "Enteric glia promote regeneration of transected dorsal root axons into spinal cord of adult rats." Exp Neurol 181(1): 79-83.
 After spinal cord injury axonal regeneration is poor, but may be enhanced by the implantation of olfactory ensheathing glia (OEG). Enteric glia (EG) share many properties of OEG. Transected dorsal root axons normally do not regenerate through the central nervous system myelin into the spinal cord. We tested whether EG, like OEG, could promote regeneration in this paradigm. Three weeks after EG implantation, numerous regenerating dorsal root axons reentered the spinal cord. Ingrowth of dorsal root axons was observed using 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate. Primary sensory afferents invaded laminae 1, 2, and 3, grew through laminae 4 and 5, and reached the dorsal gray commissure. No axonal ingrowth was observed in control animals, indicating that transplanted EG enabled regeneration of the injured dorsal root axons into the adult spinal cord. Thus, EG implantation may be beneficial in promoting axonal growth after central nervous system injury.

Jimeno, D., C. Lillo, et al. (2003). "The degenerative and regenerative processes after the elimination of the proliferative peripheral retina of fish." Exp Neurol 179(2): 210-28.
 We have analyzed the modifications in the tench (Tinca tinca) retina after the complete cryo-elimination of the proliferative growing zone (PGZ), which participates in the continuous growth of the retina throughout the life of the fish. By using immunohistochemistry and electron microscopy we demonstrated that, after the lesion, degenerative and regenerative processes take place in the PGZ, in the ciliary zone, and in the transition zone located between the PGZ and the central retina. After 120 days postlesion, the PGZ was completely regenerated and its composition was similar to that of the control animals. Numerous proliferative PCNA-positive cells reappeared and new ganglion cells were formed. In the transition zone and the central retina numerous proliferative PCNA-positive cells also appeared. These are arranged, on occasion, as columnar units from the inner to the outer nuclear layer where the rod precursors and the progenitor cells, respectively, were located. The Muller cells, closely associated with these columnar units, appeared to use them as guides to migration during the regenerative process. Notably, modifications occurred in the ciliary zone, whose cells acquired similar characteristics to the PGZ cells. The ciliary zone cells, the Muller cells, the rod precursors, and the proliferative cells located in the inner nuclear layer appear to participate actively in the regeneration of the PGZ.

Jones, L. L., D. Sajed, et al. (2003). "Axonal regeneration through regions of chondroitin sulfate proteoglycan deposition after spinal cord injury: a balance of permissiveness and inhibition." J Neurosci 23(28): 9276-88.
 Increased expression of certain extracellular matrix (ECM) molecules after CNS injury is believed to restrict axonal regeneration. The chondroitin sulfate proteoglycans (CSPGs) are one such class of ECM molecules that inhibit neurite outgrowth in vitro and are upregulated after CNS injury. We examined growth responses of several classes of axons to this inhibitory environment in the presence of a cellular fibroblast bridge in a spinal cord lesion site and after a growth factor stimulus at the lesion site (fibroblasts genetically modified to secrete NGF). Immunohistochemical analysis showed dense labeling of the CSPGs NG2, brevican, neurocan, versican, and phosphacan at the host-lesion interface after spinal cord injury (SCI). Furthermore, robust expression of NG2, and to a lesser extent versican, was also observed throughout grafts of control and NGF-secreting fibroblasts. Despite this inhibitory milieu, several axonal classes penetrated control fibroblast grafts, including dorsal column sensory, rubrospinal, and nociceptive axons. Axon growth was amplified more in the presence of NGF-secreting grafts. Confocal microscopy demonstrated that axon growth was, paradoxically, preferentially associated with NG2-rich substrates in both graft types. NG2 expression also increased after sciatic nerve injury, wherein axons successfully regenerate. Cellular sources of NG2 in SCI and peripheral nerve lesion sites included Schwann cells and endothelial cells. Notably, these same cellular sources in lesion sites produced the cell adhesion molecules L1 and laminin, and these molecules all colocalized. Thus, axons grow along substrates coexpressing both inhibitory and permissive molecules, suggesting that regeneration is successful when local permissive signals balance and exceed inhibitory signals.

Jones, L. L., R. U. Margolis, et al. (2003). "The chondroitin sulfate proteoglycans neurocan, brevican, phosphacan, and versican are differentially regulated following spinal cord injury." Exp Neurol 182(2): 399-411.
 Chondroitin sulfate proteoglycans (CSPGs) are extracellular matrix (ECM) molecules that are widely expressed throughout the developing and adult CNS. In vitro studies demonstrate their potential to restrict neurite outgrowth, and it is believed that CSPGs also inhibit axonal regeneration after CNS injury in vivo. Previous studies demonstrated that CSPGs are generally upregulated after spinal cord injury, and more recent reports have begun to identify individual proteoglycans that may play dominant roles in limiting axonal regeneration. The current study systematically examined the extended deposition patterns after CNS injury of four putatively inhibitory CSPGs that have not been extensively investigated previously in vivo: neurocan, brevican, phosphacan, and versican. After spinal cord injury, neurocan, brevican, and versican immunolabeling increased within days in injured spinal cord parenchyma surrounding the lesion site and peaked at 2 weeks. Neurocan and versican were persistently elevated for 4 weeks postinjury, and brevican expression persisted for at least 2 months. On the other hand, phosphacan immunolabeling decreased in the same region immediately following injury but later recovered and then peaked after 2 months. Combined glial fibrillary acidic protein (GFAP) immunohistochemistry and in situ hybridization demonstrated that GFAP astrocytes constituted a source of neurocan production after spinal cord injury. Thus, the production of several CSPG family members is differentially affected by spinal cord injury, overall establishing a CSPG-rich matrix that persists for up to 2 months following injury. Optimization of strategies to reduce CSPG expression to enhance regeneration may need to target several different family members over an extended period following injury.

Jordanova, A., P. De Jonghe, et al. (2003). "Mutations in the neurofilament light chain gene (NEFL) cause early onset severe Charcot-Marie-Tooth disease." Brain 126(Pt 3): 590-7.
 Neurofilament light chain polypeptide (NEFL) is one of the most abundant cytoskeletal components of the neuron. Mutations in the NEFL gene were recently reported as a cause for autosomal dominant Charcot-Marie-Tooth type 2E (CMT2E) linked to chromosome 8p21. In order to investigate the frequency and phenotypic consequences of NEFL mutations, we screened 323 patients with CMT or related peripheral neuropathies. We detected six disease associated missense mutations and one 3-bp in-frame deletion clustered in functionally defined domains of the NEFL protein. Patients have an early onset and often a severe clinical phenotype. Electrophysiological examination shows moderately to severely slowed nerve conduction velocities. We report the first nerve biopsy of a CMT patient with a de novo missense mutation in NEFL, and found an axonal pathology with axonal regeneration clusters and onion bulb formations. Our findings provide further evidence that the clinical variation observed in CMT depends on the gene mutated and the specific type of mutation, and we also suggest that NEFL mutations need to be considered in the molecular evaluation of patients with sporadic or dominantly inherited CMT.

Jubran, M. and J. Widenfalk (2003). "Repair of peripheral nerve transections with fibrin sealant containing neurotrophic factors." Exp Neurol 181(2): 204-12.
 Peripheral nerve injury is often followed by incomplete recovery of function and sometimes associated with neuropathic pain. There is, therefore, need for therapies which improve the speed of recovery and the final functional outcome after peripheral nerve injuries. In addition, neuropathic pain is not easily dealt with clinically and should preferably be eliminated. Neurotrophic factors have well-documented abilities to support neuron survival and stimulate neurite outgrowth, making them excellent candidates for use in repairing injured nerves. We investigated the possible beneficial effects of repairing the transected rat sciatic nerve by local application of a fibrin sealant containing nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF), or acidic fibroblast growth factor (aFGF). Fibrin sealant was used in conjunction with sutures. Evaluation of motor and sensory function, autotomy, and histological parameters was carried out from 1 to 12 weeks after injury. We demonstrate that NGF cotreatment decreased the occurance of autotomy, suggesting a reduction of neuropathic pain, and improved the performance in motor and sensory tests. In addition, the number of regenerating motoneurons was significantly increased after NGF administration. GDNF increased the speed of sensory recovery, but also markedly increased autotomy, indicating an increased degree of neuropathic pain. aFGF did not alter the outcome of the motor or sensory tests. Fibrin sealant could easily be used in conjunction with sutures to deliver neurotrophic substances locally to the damaged nerve and to enhance recovery of nerve function.

Jurynec, M. J., C. P. Riley, et al. (2003). "TIGR is upregulated in the chronic glial scar in response to central nervous system injury and inhibits neurite outgrowth." Mol Cell Neurosci 23(1): 69-80.
 Reactive astrocytes respond to central nervous system (CNS) injury and disease by elaborating a glial scar that is inhibitory to axonal regeneration. To identify genes that may be involved in the astrocytic response to injury, we used differential display polymerase chain reaction and an in vivo model of the CNS glial scar. Expression of the trabecular meshwork inducible glucocorticoid response (TIGR) gene was increased in gliotic tissue compared with the uninjured cerebral cortex. Increased TIGR expression by reactive astrocytes was confirmed by in situ hybridization, quantitative reverse transcriptase-polymerase chain reaction, immunoblot analysis, and immunohistochemistry. Although mutations of the TIGR gene have been implicated in glaucoma, a function for TIGR has not been reported. Since TIGR is secreted, we assessed a possible role in inhibition of neuronal regeneration with an in vitro bioassay and found that this protein is a potent inhibitor of neurite outgrowth. Thus, TIGR is a newly identified component of the CNS glial scar that is likely to contribute to neuronal regenerative failure characteristic of the mammalian CNS.

Kaas, J. H. and C. E. Collins (2003). "Anatomic and functional reorganization of somatosensory cortex in mature primates after peripheral nerve and spinal cord injury." Adv Neurol 93: 87-95.
 
Kakinoki, R., R. Ikeguchi, et al. (2003). "Treatment of painful peripheral neuromas by vein implantation." Int Orthop 27(1): 60-4.
 Firstly, we designed a vein-implantation model using the rat femoral nerve and vein to study the morphometric changes in nerve endings inserted into venous lumina. By 4 weeks, nerve fibers had extended from the nerve stump into the lumen of the vein and along the endothelium of the vein. After 8 weeks, the lengths and number of nerve fibres extending into the vein lumen began to decrease. At 12 weeks, the nerve ending had developed a hemispherical shape. In none of the experiments was a neuroma formed. Secondly, we treated ten neuromas in ten patients by the vein-implantation method. We obtained excellent results in seven patients.

Kamijo, Y., J. Koyama, et al. (2003). "Regenerative process of the facial nerve: rate of regeneration of fibers and their bifurcations." Neurosci Res 46(2): 135-43.
 After the main trunk of the mouse facial nerve was injured by crushing, a fiber tracing method was used to quantify the facial motor neurons that extended regenerating nerve fibers to the specific site of the facial nerve branch. The total number of motor neurons retrogradely labeled with a fluorescent tracer, Fluoro-Gold (FG), were 0 on postsurgical days (PSDs) 1 and 2, 75+/-25 on PSD3, 264+/-21 on PSD4, 378+/-19 on PSD6, 428+/-19 on PSD8, 491+/-13 on PSD12 and 532+/-15 on PSD16. Assuming that the FG-positive neurons (535+/-11) of the control mice represent 100%, the FG-labeled neurons accounted for 0, 14, 49, 71, 80, 92 and 99% on the corresponding days. Two different fluorescent tracers were applied to the different facial nerve branches 16 days after facial nerve injuries. Double-labeled neurons were consistently found in the nerve-crushed facial nucleus (3.2%), and their number increased in the nerve-transected facial nucleus (12.2%). The present study indicates that the regenerating facial nerve consists of heterogeneous nerve fibers with varying growth rates and that excessive axonal branching occurs more frequently in the nerve-transected than in the nerve-crushed injuries.

Kanemaru, S., T. Nakamura, et al. (2003). "Recurrent laryngeal nerve regeneration by tissue engineering." Ann Otol Rhinol Laryngol 112(6): 492-8.
 The recurrent laryngeal nerve (RLN) does not regenerate well after it has been cut, and no current surgical methods achieve functional regeneration. Here, we evaluate the functional regeneration of the RLN after reconstruction using a biodegradable nerve conduit or an autologous nerve graft. The nerve conduit was made of a polyglycolic acid (PGA) tube coated with collagen. A 10-mm gap in the resected nerve was bridged by a PGA tube in 6 adult beagle dogs (group 1) and by an autologous nerve graft in 3 dogs (group 2). Fiberscopic observation revealed functional regeneration of the RLN in 4 of the 6 dogs in group 1. No regeneration of the RLN was observed in any dog in group 2. We also tested for axonal transport, and measured the compound muscle action potential. The RLN can be functionally regenerated with a PGA tube, which may act as a scaffold for the growth of regenerating axons.

Kapur, T. A. and M. S. Shoichet (2003). "Chemically-bound nerve growth factor for neural tissue engineering applications." J Biomater Sci Polym Ed 14(4): 383-94.
 In order to promote regeneration after spinal cord injury, growth factors have been applied in vivo to rescue ailing neurons and provide a path finding signal for regenerating neurites. We previously demonstrated that soluble growth factor concentration gradients can guide axons over long distances, but this model is inherently limited to in vitro applications. To translate the use of growth factor gradients to an implantible device for in vivo studies, we developed a photochemical method to bind nerve growth factor (NGF) to microporous poly(2-hydroxyethylmethacrylate) (PHEMA) gels and tested bioactivity in vitro. A cell adhesive photoreactive poly(allylamine) (PAA) was synthesized and characterized. This photoreactive PAA was applied to the surface of the PHEMA gels to provide both a cell adhesive layer and a photoreactive handle for further NGF immobilization. Using a direct ELISA technique, the amount of NGF immobilized on the surface of PHEMA after UV exposure was determined to be 5.65 +/- 0.82 ng/cm2 or 3.4% of the originally applied NGF. A cell-based assay was performed to determine the bioactivity of the immobilized NGF. Using pheochromocytoma (PC-12) cells, 30 +/- 7% of the cell population responded to bound NGF, a response statistically similar to that of cells cultured on collagen in the presence of 40 ng/ml soluble NGF of 39 +/- 12%. These results demonstrate that PHEMA with photochemically bound NGF is bioactive. This photochemical technique may be useful to spatially control the amount of NGF bound to PHEMA using light and thus build a stable concentration gradient.

Kato, R., S. Kiryu-Seo, et al. (2003). "Cavernous nerve injury elicits GAP-43 mRNA expression but not regeneration of injured pelvic ganglion neurons." Brain Res 986(1-2): 166-73.
 Recovery of erectile dysfunction after cavernous nerve injury takes a long period. To elucidate this mechanism, unilateral cavernous nerve of male rat was cut, and the expression level of a nerve regeneration marker, the growth associated protein-43 (GAP-43) mRNA was evaluated by in situ hybridization and RT-PCR. While GAP-43 mRNA expression was transiently increased in the injured neurons of the major pelvic ganglion (MPG) at 7 days after nerve injury, continuous increase of GAP-43 mRNA was observed in the contralateral MPG from 7 days to 6 months after the nerve injury. Histochemical double-labeling studies for either neuronal NOS (nNOS) or tyrosine hydroxylase (TH) and the GAP-43 mRNA expression demonstrated that in injured MPG the transient up-regulation of GAP-43 mRNA was mainly seen in nNOS negative and/or TH positive neurons, suggesting non-parasympathetic post-ganglionic neurons, and also demonstrated that in contralateral MPG GAP-43 mRNA positive neurons were gradually increased in nNOS positive but TH negative neurons, suggesting parasympathetic post-ganglionic neurons. When a retrograde tracer Fluorogold (FG) was injected into the penile crus 7 days before histological experiments, FG-positive neurons were, if any, hardly seen in nNOS-positive neurons of the injured MPG for at least 6 months, whereas numerous FG-positive cells were seen in nNOS-positive neurons of the contralateral MPG. These results suggest that post-ganglionic projecting neurons of the intact side, which express increased GAP-43 mRNA, would be most likely to contribute to the recovery of the erectile function after unilateral cavernous nerve injury possibly by a plastic change such as nerve sprouting.

Kawamoto, K., S. Ishimoto, et al. (2003). "Math1 gene transfer generates new cochlear hair cells in mature guinea pigs in vivo." J Neurosci 23(11): 4395-400.
 Hair cell loss in the mammalian cochlea is irreversible and results in permanent hearing loss. Math1, the basic helix-loop-helix transcription factor homolog of the Drosophila atonal gene, is a positive regulator of hair cell differentiation during cochlear development. Developing hair cells express Math1, and nonsensory cells do not. We set out to determine the outcome of overexpression of Math1 in nonsensory cells of the cochlea on the phenotype of these cells. We demonstrate that in vivo inoculation of adenovirus with the Math1 gene insert into the endolymph of the mature guinea pig cochlea results in Math1 overexpression in nonsensory cochlear cells, as evident from the presence of Math1 protein in supporting cells of the organ of Corti and in adjacent nonsensory epithelial cells. Math1 overexpression leads to the appearance of immature hair cells in the organ of Corti and new hair cells adjacent to the organ of Corti in the interdental cell, inner sulcus, and Hensen cell regions. Axons are extended from the bundle of auditory nerve toward some of the new hair cells, suggesting that the new cells attract auditory neurons. We conclude that nonsensory cells in the mature cochlea retain the competence to generate new hair cells after overexpression of Math1 in vivo and that Math1 is necessary and sufficient to direct hair cell differentiation in these mature nonsensory cells.

Kawasaki, T., N. Oka, et al. (2003). "Oct6, a transcription factor controlling myelination, is a marker for active nerve regeneration in peripheral neuropathies." Acta Neuropathol (Berl) 105(3): 203-8.
 Three transcription factors, Krox20 (EGR2), Oct6 (SCIP/Tst1) and Sox10, are considered necessary for transition from the nonmyelinating to the myelinating stage of Schwann cell development. We immunohistochemically studied Oct6 expression in peripheral nerve specimens from 25 patients with various diseases including Charcot-Marie-Tooth disease type 1A (CMT1A). Oct6 was present in cytoplasm of Schwann cells associated with normal-appearing myelinated nerve fibers, but not in nuclei. Expression was seen in nuclei of Schwann cells in the early phase of acute axonal degeneration; nuclear expression peaked at the regenerative stage. Schwann cells forming "onion bulbs" expressed Oct6 in chronic inflammatory demyelinating polyneuropathy (CIDP), but showed minimal expression in CMT1A, reflecting their proliferative activity in CIDP. Nerves showing chronic axonal loss had no expression. Oct6, then, may be a marker for dedifferentiation of adult Schwann cells and active nerve regeneration.

Keilhoff, G., H. Fansa, et al. (2003). "Nitric oxide synthase, an essential factor in peripheral nerve regeneration." Cell Mol Biol (Noisy-le-grand) 49(6): 885-97.
 Nitric oxide (NO) exerts both, pro-apoptotic and anti-apoptotic actions and appears to be acritical factor inneuronal degenerative and regenerative processes. NO is synthesized from L-arginine by NO synthase occurring in three isoforms of (neuronal, nNOS; endothelial, eNOS; inducible, iNOS). In a mice sciatic nerve model the regenerative outcome was assessed when the endogenous NO supply was deficient by knocking out the respective NOS isoform and compared to that of wild type mice after nerve transection. In nNOS knock-out mice a delay in regeneration, preceded by slowedWallerian degeneration and a disturbed pruning of uncontrolled sprouts, was observed. This was associated with a delayed recovery of sensory and motor function. Additionally, deficiency of nNOS led after nerve cut to a substantial loss of small and medium-sized dorsal root ganglia neurons, spinal cord interneurons and, to a lesser extent, spinal cord motor neurons. A lack of iNOS resulted in a delayed Wallerian degeneration and impaired regenerative outcome without consequences for neuronal survival. A lack of eNOS was well tolerated, although a delay in nerve revascularization was observed. Thus, after peripheral nerve lesion, regular NOS activity is essential for cell survival and recovery with reference to the nNOS isoform.

Keilhoff, G., F. Stang, et al. (2003). "Bio-compatibility of type I/III collagen matrix for peripheral nerve reconstruction." Biomaterials 24(16): 2779-87.
 Nerve gaps are usually bridged by autografts. With improving technical methods biocompatible conduits may become an alternative graft to reconstruct nerves. Non-neural conduits fail to support regeneration over larger gaps due to lacking viable Schwann cells. Thus, tissue engineering of nerves is focusing on implantation of viable Schwann cells into suitable scaffolds. In this study, we tested collagen type I/III tubes as a potential nerve guiding matrix. Revascularization, foreign body reaction, biodegradation and Schwann cell settlement were evaluated by immunocytochemistry, light, fluorescence and scanning electron microscopy, after different implantation times. The conduits were completely revascularized between day 5 and 7 post-operatively and well integrated into the host tissue. Host response was characterized by a moderate invasion of ED1/ED2-positive macrophages. Biodegradation of the tubes was slowly enough to maintain a stable support structure for extended regeneration processes. Implanted Schwann cells adhered, survived and proliferated on the inner surface of the conduits and were able to form nerve guiding columns of Bungner. From this results, we conclude that collagen-type I/III can serve as template to design "living" nerve conduits, which may be able to ensure nerve regeneration through extended nerve gaps.

Kerber, G., R. Streif, et al. (2003). "Neuregulin-1 isoforms are differentially expressed in the intact and regenerating adult rat nervous system." J Mol Neurosci 21(2): 149-65.
 Our knowledge on Neuregulin-1 (Nrg-1) during development of the nervous system is increasing rapidly, but little is known about Nrg-1-ErbB signaling in the adult brain. Nrg-1 is involved in determination, proliferation, differentiation, and migration of neurons and glial cells in the developing brain. In the peripheral nervous system, Nrg-1 signaling is required for Schwann cell differentiation and myelination, and establishment of neuromuscular junctions (NMJs). Multiple alternative splicing of Nrg-1 was shown, but correlation of its structural and functional diversity was rarely addressed. Therefore, we investigated the expression of Nrg-1 isoforms in the rat brain and brain-derived cell types, and their involvement in regeneration of the adult brain, using immunohistochemistry, in situ hybridization, and semiquantitative RT-PCR. We found expression of at least 12 distinct Nrg-1 isoforms in the brain and altered expression of several isoforms in the facial motor nucleus after peripheral transection of the seventh cranial nerve. An upregulation of Nrg-1 type-I mRNA, probably type- I-alpha, was observed in reactive astrocytes of the facial nucleus 1 d postaxotomy. Nrg-1 type-III and the splice variants beta1 and beta5 are dramatically downregulated in axotomized motoneurons, which lack contact to their target tissue. Baseline expression levels were reestablished when the first axons reached the facial muscles and reformed NMJs. Nrg-1-beta1 and -beta5 might act in maintenance of NMJs. The splice variants beta2 and beta4 display an initial downregulation of mRNA levels, followed by an increase during the period of axon remyelination. Thus, Nrg- 1-beta2 and -beta4 might be involved in myelination.

Kerns, J. M., N. Danielsen, et al. (2003). "A comparison of peripheral nerve regeneration in acellular muscle and nerve autografts." Scand J Plast Reconstr Surg Hand Surg 37(4): 193-200.
 Regeneration of the rat sciatic nerve through acellular muscle and nerve autografts was evaluated 6-28 days postoperatively by the sensory pinch test, immunocytochemical staining for neurofilaments, and light and electron microscopy. Data points generated by the pinch test were plotted against postoperative time periods and by the use of regression analysis the initial delay period for muscle grafts was determined to 10.3 days. This value was similar to that previously published for acellular nerve grafts (9.5 days), but significantly longer than that for fresh nerve grafts (3.6 days). The calculated regeneration rate (slope of the regression line) for muscle grafts (1.8 mm/day) did not differ significantly (p > 0.05) from that calculated for acellular nerve grafts (2.1 mm/day) or for fresh nerve grafts (1.5 mm/day). The front of regenerating axons shown by axonal neurofilament staining confirmed the pinch test results. Both types of acellular grafts were repopulated with host non-neuronal cells and the muscle graft contained occasional ectopic muscle fibres. Remnants of graft basal laminae were evident at the ultrastructural level. These results indicate the suitability of either acellular muscle or nerve grafts for nerve repair despite their prolonged initial delay periods compared with conventional fresh nerve grafts.

Kerns, J. M., S. Shott, et al. (2003). "Effects of IGF-I gene therapy on the injured rat pudendal nerve." Int Urogynecol J Pelvic Floor Dysfunct 14(1): 2-7; discussion 8.
 Injured nerves and their motor units may undergo enhanced recovery when exposed to recombinant human insulin-like growth factor-I (rhIGF-I). The external anal sphincter muscle in the female rat was denervated to model incontinence. The treatment-group muscle was injected with rhIGF-1 plasmid, whereas in the control group the plasmid lacked the cDNA insert and the normal group received neither surgery nor treatment. Electromyography data at 56 days post surgery indicated more reinnervation without fibrillation potentials in the treatment group (2 of 6) than in the control group (0 of 6). The histology of the regenerated axons in the pudendal nerve distal to the crush site also suggested an improved recovery in the treatment group. The number of motor neurons retrogradely labeled with horseradish peroxidase was decreased by 50% following pudendal nerve crush in both experimental groups compared to the normal group. We conclude from these preliminary results that rhIGF-I gene therapy may improve the distal recovery of structure and function.

Khodr, B., J. Howard, et al. (2003). "Effect of short-term and long-term antioxidant therapy on primary and secondary ageing neurovascular processes." J Gerontol A Biol Sci Med Sci 58(8): 698-708.
 Previous studies from our laboratory demonstrated an age-related functional decline in sensory neurones and their modulation of microvascular blood flow (primary ageing processes) that correlated with a deficiency in tissue repair (a secondary ageing process). We also raised the notion of a possible role for free radicals in these age-related changes. The aim of this study was to investigate the impact of antioxidant therapy on modulating sensory neurovascular function and tissue repair with age. Twenty-four-month-old Sprague-Dawley rats were treated with vitamin E for short-term (40 mg/kg, i.p., every other day for 2 weeks) or long-term (for 12 months in advance, 10 g/kg, incorporated in food). These treated rats were assessed for the effectiveness of treatment and tested for their sensory neurovascular function, repair of full-thickness burn, and recovery from hyperalgesia following nerve injury. The results indicate that both short- and long-term vitamin E treatments are effective in improving sensory neurovascular function and in reducing the time required for complete wound closure of full-thickness burn injury. Short-term vitamin E treatment was more effective in protecting against the development of hyperalgesia following nerve injury. An initial increase in wound size and in hyperalgesia was observed in the treated animals, and could reflect possible side effects of the antioxidant therapy and support the importance of free radicals in early stages of the repair process. The data, overall, support the notion that oxidative damage contributes to both primary and secondary ageing processes.

Kieseier, B. C. and H. P. Hartung (2003). "Multiple paradigm shifts in multiple sclerosis." Curr Opin Neurol 16(3): 247-52.
 PURPOSE OF REVIEW: The present article reviews the currently ongoing scientific debate of our changing views on the pathogenesis of multiple sclerosis and the therapeutic strategies currently available for multiple sclerosis. RECENT FINDINGS: The most important observations include that (a) axonal loss accounts for permanent disability in multiple sclerosis, (b) remyelination should be possible in theory but fails for unknown reasons in the multiple sclerosis lesion, (c) inflammation can be beneficial, (d) treatment should be initiated early, and (e) immunosuppressive strategies exhibit beneficial effects in progressive forms of the disease. SUMMARY: Our current understanding of the immunopathogenesis of multiple sclerosis has changed in the past. Whereas demyelination was originally thought to be relevant for the lasting neurological deficit, it is nowadays commonly accepted that the extent of axonal loss dictates the degree of permanent clinical disability. How axonal damage can be prevented remains elusive. The interaction between the myelinating cell and the neuron gains increasing attention, however the evolving knowledge has not yet yielded new treatment concepts. Hence for the time being, it seems prudent to make optimal use of current approved therapies. Recent trials underlined the need for early initiation of treatment with immunomodulatory drugs. The superiority of one of the interferons is still a matter of debate, and a conclusive answer cannot be given at present. Finally, with mitoxantrone we have a drug at hand which can be used in progressive forms of multiple sclerosis, especially when other disease modifying drugs are not or no longer effective.

Kikuchi, K., A. Kishino, et al. (2003). "In vitro and in vivo characterization of a novel semaphorin 3A inhibitor, SM-216289 or xanthofulvin." J Biol Chem 278(44): 42985-91.
 SM-216289 (xanthofulvin) isolated from the fermentation broth of a fungal strain, Penicillium sp. SPF-3059, was identified as a strong semaphorin 3A (Sema3A) inhibitor. Sema3A-induced growth cone collapse of dorsal root ganglion neurons in vitro was completely abolished in the presence of SM-216289 at levels less than 2 mum (IC50 = 0.16 mum). When dorsal root ganglion explants were co-cultured with Sema3A-producing COS7 cells in a collagen gel matrix, SM-216289 enabled neurites to grow toward the COS7 cells. SM-216289 diminished the binding of Sema3A to its receptor neuropilin-1 in vitro, suggesting a direct interference of receptor-ligand association. Moreover, our data suggest that SM-216289 interacted with Sema3A directly and blocked the binding of Sema3A to its receptor. We examined the efficacy of SM-216289 in vivo using a rat olfactory nerve axotomy model, in which strong Sema3A induction has been reported around regenerating axons. The regeneration of olfactory nerves was significantly accelerated by a local administration of SM-216289 in the lesion site, suggesting the involvement of Sema3A in neural regeneration as an inhibitory factor. SM-216289 is an excellent molecular probe to investigate the function of Sema3A, in vitro and in vivo, and may be useful for the treatment of traumatic neural injuries.

Kim, D. H., Y. J. Cho, et al. (2003). "Surgical outcomes of 111 spinal accessory nerve injuries." Neurosurgery 53(5): 1106-12; discussion 1102-3.
 OBJECTIVE: Iatrogenic injury to the spinal accessory nerve is not uncommon during neck surgery involving the posterior cervical triangle, because its superficial course here makes it susceptible. We review injury mechanisms, operative techniques, and surgical outcomes of 111 surgical repairs of the spinal accessory nerve. METHODS: This retrospective study examines clinical and surgical experience with spinal accessory nerve injuries at the Louisiana State University Health Sciences Center during a period of 23 years (1978-2000). Surgery was performed on the basis of anatomic and electrophysiological findings at the time of operation. Patients were followed up for an average of 25.6 months. RESULTS: The most frequent injury mechanism was iatrogenic (103 patients, 93%), and 82 (80%) of these injuries involved lymph node biopsies. Eight injuries were caused by stretch (five patients) and laceration (three patients). The most common procedures were graft repairs in 58 patients. End-to-end repair was used in 26 patients and neurolysis in 19 patients if the nerve was found in continuity with intraoperative electrical evidence of regeneration. Five neurotizations, two burials into muscle, and one removal of ligature material were also performed. More than 95% of patients treated by neurolysis supported by positive nerve action potential recordings improved to Grade 4 or higher. Of 84 patients with lesions repaired by graft or suture, 65 patients (77%) recovered to Grade 3 or higher. The average graft length was 1.5 inches. CONCLUSION: Surgical exploration and repair of spinal accessory nerve injuries is difficult. With perseverance, however, these patients with complete or severe deficits achieved favorable functional outcomes through operative exploration and repair.

Kim, J. E., I. E. Bonilla, et al. (2003). "Nogo-C is sufficient to delay nerve regeneration." Mol Cell Neurosci 23(3): 451-9.
 Axonal regeneration succeeds in the peripheral but not central nervous system of adult mammals. Peripheral clearance of myelin coupled with selective CNS expression of axon growth inhibitors, such as Nogo, may account for this reparative disparity. To assess the sufficiency of Nogo for limiting axonal regeneration, we generated transgenic mice expressing Nogo-C in peripheral Schwann cells. Nogo-C includes the panisoform inhibitory Nogo-66 domain, but not a second Nogo-A-specific inhibitory domain, allowing a selective consideration of the Nogo-66 region. The oct-6::nogo-c transgenic mice regenerate axons less rapidly than do wild-type mice after mid-thigh sciatic nerve crush. The delayed axonal regeneration is associated with a decreased recovery rate for motor function after sciatic nerve injury. Thus, expression of the Nogo-66 domain by otherwise permissive myelinating cells is sufficient to hinder axonal reextension after trauma.

Kim, D. H., Y. J. Cho, et al. (2003). "Outcomes of surgery in 1019 brachial plexus lesions treated at Louisiana State University Health Sciences Center." J Neurosurg 98(5): 1005-16.
 OBJECT: Outcomes of 1019 brachial plexus lesions in patients who underwent surgery at Louisiana State University Health Sciences Center during a 30-year period are reviewed in this paper to provide management guidelines. METHODS: Causes of brachial plexus lesions included 509 stretches/contusions (50%), 161 plexus tumors (16%), 160 thoracic outlet syndromes (TOSs, 16%), 118 gunshot wounds (12%), and 71 lacerations (7%). Many features of clinical presentation, including prior treatment, patient's neurological status, results of electrophysiological studies, intraoperative findings, and postoperative level of function, were studied. The minimum follow-up period was 18 months and the mean follow-up period was 42 months. Repairs were best for injuries located at the C-5, C-6, and C-7 levels, the upper and middle trunk, the lateral cord to the musculocutaneous nerve, and the median and posterior cords to the axillary and radial nerves. Conversely, results were poor for injuries at the C-8 and T-1 levels, and for lower trunk and medial cord lesions, with the exception of injuries of the medial cord to the median nerve. Outcomes were most favorable when patients were carefully evaluated and selected for surgery, although variables such as lesion type, location, and severity, as well as time since injury also affected outcome. This was true also of TOSs and tumors arising from the plexus, especially if they had not been surgically treated previously. CONCLUSIONS: Surgical exploration and repair of brachial plexus lesions is technically feasible and favorable outcomes can be achieved if patients are thoroughly evaluated and appropriately selected.

Kim, J. E., S. Li, et al. (2003). "Axon regeneration in young adult mice lacking Nogo-A/B." Neuron 38(2): 187-99.
 After injury, axons of the adult mammalian brain and spinal cord exhibit little regeneration. It has been suggested that axon growth inhibitors, such as myelin-derived Nogo, prevent CNS axon repair. To investigate this hypothesis, we analyzed mice with a nogo mutation that eliminates Nogo-A/B expression. These mice are viable and exhibit normal locomotion. Corticospinal tract tracing reveals no abnormality in uninjured nogo-A/B(-/-) mice. After spinal cord injury, corticospinal axons of young adult nogo-A/B(-/-) mice sprout extensively rostral to a transection. Numerous fibers regenerate into distal cord segments of nogo-A/B(-/-) mice. Recovery of locomotor function is improved in these mice. Thus, Nogo-A plays a role in restricting axonal sprouting in the young adult CNS after injury.

Kimura, H., M. Kawatani, et al. (2003). "Effects of pituitary adenylate cyclase-activating polypeptide on facial nerve recovery in the Guinea pig." Laryngoscope 113(6): 1000-6.
 OBJECTIVES/HYPOTHESIS: Pituitary adenylate cyclase-activating polypeptide (PACAP) has neurotrophic effects of neural regeneration and gives protection to the nervous system. We investigated whether PACAP had a neurotrophic effect on peripheral motoneurons and whether PACAP could facilitate glial cell line-derived neurotrophic factor (GDNF), a neurotrophin, in nerve regeneration. The presence and distribution of PACAP receptors following facial nerve transection were also investigated. STUDY DESIGN: Animal experiment. METHODS: Unilateral transection of the facial nerve was performed in male Hartley guinea pigs, and PACAP was injected at the site. Saline was substituted as a control. Compound muscle action potentials were recorded to measure the changes of latency. Glial cell line-derived neurotrophic factor (GDNF) content in facial target muscle was measured using enzyme-linked immunosorbent assay. The regenerating site was taken for histological studies. RESULTS: Pituitary adenylate cyclase-activating polypeptide hastened the appearance of compound muscle action potentials and shortened the latency. Pituitary adenylate cyclase-activating polypeptide increased and prolonged the nerve transection-induced GDNF increase in the facial muscles. The number of myelinated fibers at 1 to 4 weeks after the transection was increased. PAC1 receptor or VPAC1 receptor or both were identified in the injury area at 2 to 4 weeks. CONCLUSIONS: Pituitary adenylate cyclase-activating polypeptide facilitated the recovery of latency of compound muscle action potentials or the number of myelinated axons, or both. Pituitary adenylate cyclase-activating polypeptide prolonged the GDNF levels in target organs. These data indicated that PACAP promoted regeneration of the facial nerve.

King, C. E., A. Wallace, et al. (2003). "Transient up-regulation of retinal EphA3 and EphA5, but not ephrin-A2, coincides with re-establishment of a topographic map during optic nerve regeneration in goldfish." Exp Neurol 183(2): 593-9.
 Eph tyrosine kinase receptors and their ligands, the ephrins, play a key role in the establishment of retinotectal topography during development. Tectal up-regulation of ephrin-A2 in goldfish, coincident with the reestablishment of a retinotectal map, suggests a similar role during optic nerve regeneration. Here we report a complementary study of EphA3, EphA5 and ephrin-A2 expression in the retina. EphA3 and EphA5 are transiently up-regulated as ascending naso-temporal gradients, whereas ephrin-A2 remains uniform. The expression profiles differ from those in developing chick and mouse, suggesting that different combinations of retinal Eph receptors and ligands can generate topographic guidance information.

King, C. T., L. D. Deyrup, et al. (2003). "Effects of gustatory nerve transection and regeneration on quinine-stimulated Fos-like immunoreactivity in the parabrachial nucleus of the rat." J Comp Neurol 465(2): 296-308.
 The distribution of quinine-stimulated Fos-like immunoreactivity (FLI) in several subdivisions of the parabrachial nucleus (PBN) known to be responsive to gustatory stimulation was examined in rats in which the chorda tympani nerve (CT) and/or glossopharyngeal nerve (GL) was transected (Experiment 1) and in rats in which the GL was transected with regeneration promoted or prevented (Experiment 2). We confirmed previous findings in the literature by demonstrating that rats intraorally infused with 3 mM quinine showed a robust population of FLI in the waist area and the external lateral (EL) and external medial (EM) subdivisions of the PBN (Yamamoto et al. [1994] Physiol Behav 56:1197-1202; Travers et al., [ 1999] Am J Physiol 277:R384-R394). In the waist area, only GL transection significantly decreased the number of FLI-neurons elicited by intraoral infusion of quinine compared with water-stimulated controls. In the external subdivisions neither neurotomy affected the number of FLI-neurons. The effect of GL transection in the waist area was enduring for rats in which the GL did not regenerate (up to 94 days), but regeneration of the GL after 52 days restored quinine-stimulated FLI to control values. In these same GL-transected animals, there were parallel decreases in the number of gapes elicited by intraoral quinine stimulation that recovered, but only subsequent to regeneration of the GL. These data provide support for the role of the waist area in the brainstem processing that underlies oromotor rejection behaviors and also help substantiate the hypothesis that the CT and GL are relatively specialized with regard to function. Moreover, when the quinine-induced pattern of neural activity in the second central gustatory relay, as assessed by FLI, is substantially altered by the loss of peripheral gustatory input from the GL, it can be restored upon regeneration of the nerve.

King, V. R., M. Henseler, et al. (2003). "Mats made from fibronectin support oriented growth of axons in the damaged spinal cord of the adult rat." Exp Neurol 182(2): 383-98.
 A variety of biological as well as synthetic implants have been used to attempt to promote regeneration into the damaged spinal cord. We have implanted mats made from fibronectin (FN) into the damaged spinal cord to determine their effectiveness as a substrate for regeneration of axons. These mats contain oriented pores and can take up and release growth factors. Lesion cavities 1 mm in width and depth and 2 mm in length were created on one side of the spinal cord of adult rats. FN mats containing neurotrophins or saline were placed into the lesion. Mats were well integrated into surrounding tissue and showed robust well-oriented growth of calcitonin gene-related peptide, substance P, GABAergic, cholinergic, glutamatergic, and noradrenergic axons into FN mats. Transganglionic tracing using cholera toxin B indicated large-diameter primary afferents had grown into FN implants. Schwann cells had also infiltrated FN mats. Electron microscopy confirmed the presence of axons within implants sites, with most axons either ensheathed or myelinated by Schwann cells. Mats incubated in brain-derived neurotrophic factor and neurotrophin-3 showed significantly more neurofilament-positive and glutamatergic fibers compared to saline- and nerve growth factor-incubated mats, while mats incubated with nerve growth factor showed more calcitonin gene-related peptide-positive axons. In contrast, neurotrophin treatment had no effect on PGP 9.5-positive axons. In addition, in some animals with neurotrophin-3-incubated mats, cholera toxin B-labelled fibers had grown from the mat into adjoining intact areas of spinal cord. The results indicate that FN mats provide a substrate that is permissive for robust oriented axonal growth in the damaged spinal cord, and that this growth is supported by Schwann cells.

Kirby, B. P. and J. N. Rawlins (2003). "The role of the septo-hippocampal cholinergic projection in T-maze rewarded alternation." Behav Brain Res 143(1): 41-8.
 Administration of 192IgG-saporin, a cholinergic neurotoxin, to the medial septum destroys the cell bodies from which the septo-hippocampal cholinergic projection originates, leading to reductions in both hippocampal acetylcholinesterase (AChE) and choline acetyltransferase (ChAT). Despite reports that 192IgG-saporin-induced cholinergic loss leads to post-operative impairments in acquisition and performance of spatial memory tasks, a number of other reports have described intact spatial memory performance following these lesions. Factors that might account for these different outcomes include variations in toxin injection sites or volumes, and post-operative testing at times that might permit regeneration of damaged neuronal processes. We, therefore, assessed the effects of intraseptal microinjection of 192IgG-saporin, in rats, on the post-operative retention of pre-operatively acquired discrete-trial rewarded alternation in the T-maze. This design allowed us to assess the effects of the lesion 7 days post-surgery, at which point, at best, incomplete neuronal regeneration would have been expected to have occurred. The lesion led to a profound loss of hippocampal AChE staining, and a clear inflammatory response, as assessed by proliferation of OX42-stained macrophages in the medial septum and diagonal band nuclei, but there was no impairment in spatial working memory.

Kishino, A. and C. Nakayama (2003). "Enhancement of BDNF and activated-ERK immunoreactivity in spinal motor neurons after peripheral administration of BDNF." Brain Res 964(1): 56-66.
 Brain-derived neurotrophic factor (BDNF) shows neurotrophic effects on adult motor neurons when given systemically, But it is unknown whether systemically administered BDNF is transported to central cell bodies to affect them directly. Here we used immunohistochemistry to investigate the transport of peripherally injected BDNF to spinal motor neurons and the subsequent activation of a signaling pathway. We first injected BDNF into the flexor digitorum brevis (FDB) and analyzed the motor nucleus that projects to the FDB for BDNF immunoreactivity (BDNF-ir) and phosphorylated extracellular signal-regulated kinase (ERK) 1/2 immunoreactivity (pERK1/2-ir). Both immunoreactivities were observed in the motor neuron cell bodies. Next, BDNF was injected subcutaneously (s.c.) into rats with a unilaterally axotomized sciatic nerve. pERK1/2-ir was detected in motor neurons of the lesioned side. BDNF-ir and pERK1/2-ir were also observed on the unlesioned side when a high dose of BDNF was injected. Therefore, we examined BDNF-ir and pERK1/2-ir after injecting BDNF s.c. into normal rats. Both immunoreactivities were observed in motor nuclei on both sides. Finally, we examined pERK1/2-ir after a lower dose of BDNF was injected, which prevents the decrease in choline acetyl transferase that occurs in the motor neuron upon axotomy. Spinal motor nuclei contained a few cell bodies with pERK1/2-ir. These findings represent the first direct evidence that subcutaneously injected BDNF is transported to motor neurons and that it activates a signaling pathway in the spinal cord and exhibits neurotrophic effects in vivo.

Kiwaki, T., F. Umehara, et al. (2003). "The clinical and pathological features of peripheral neuropathy accompanied with HTLV-I associated myelopathy." J Neurol Sci 206(1): 17-21.
 We describe the clinical and pathological studies in HTLV-I associated myelopathy (HAM)/tropical spastic paraparesis (TSP) patients with peripheral neuropathy as proven by sural nerve biopsy. Sural nerve pathology in HAM/TSP patients revealed that the most common type of pathologic change is a combination of both demyelination and remyelination and axonal degeneration and regeneration, and this change is modified by the complications. The pathologic changes were correlated with neither the duration of disease nor human T lymphotropic virus type I (HTLV-I) proviral load. This study suggests that peripheral nerves could be involved in HAM/TSP.

Kobayashi, T., K. Kihara, et al. (2003). "Spontaneous regeneration of the seriously injured sympathetic pathway projecting to the prostate over a long period in the dog." BJU Int 91(9): 868-72.
 OBJECTIVES: To explore the spontaneous regeneration, over a long period, of the seriously injured sympathetic pathway controlling the prostate. MATERIALS AND METHODS: The hypogastric nerve (HGN), which is part of the sympathetic pathway from the spinal cord to the prostate, was partly removed over half of its length on both sides in six dogs. Four years after surgery the responses of the prostate to electrical stimulation of the lumbar splanchnic nerve (LSN) or the HGN proximal to the site removed, were assessed. RESULTS: In six dogs, 10 of the 17 LSNs (second to fourth) and four of the 10 HGNs stimulated elicited prostatic contraction. The pathways via the ipsilateral HGN and/or the contralateral HGN from the LSNs to the prostate were identified as having regenerated in four of six dogs. CONCLUSION: These results indicate that the sympathetic pathways via the HGN to the canine prostate can regenerate spontaneously over a long period after serious injury, and that their cross-innervation system can also be repaired.

Kokaia, Z. and O. Lindvall (2003). "Neurogenesis after ischaemic brain insults." Curr Opin Neurobiol 13(1): 127-32.
 Evidence for neuronal self-repair following insults to the adult brain has been scarce until very recently. Ischaemic insults have now been shown to trigger neurogenesis from neural stem cells or progenitor cells located in the dentate subgranular zone, the subventricular zone lining the lateral ventricle, and the posterior periventricle adjacent to the hippocampus. New neurons migrate to the granule cell layer or to the damaged CA1 region and striatum, where they express morphological markers characteristic of those neurons that have died. Some evidence indicates that these neurons can re-establish connections and contribute to functional recovery.

Kolb, B. and J. Cioe (2003). "Recovery from early cortical damage in rats. IX. Differential behavioral and anatomical effects of temporal cortex lesions at different ages of neural maturation." Behav Brain Res 144(1-2): 67-76.
 Rats were given lesions of the temporal association cortex on postnatal day 4 or 10, or in adulthood. Ninety days later they were trained on two visual tasks (visual-spatial navigation; horizontal-vertical stripes discrimination). Lesion animals were compared behaviorally and neuroanatomically to littermate sham control rats. The day 4 lesions produced a larger deficit in the navigation task than day 10 or adult lesions. There were no deficits in the discrimination task. Analysis of the brains showed that the day 4 lesions produced a smaller brain and thinner cortex than day 10 lesions. The day 10 lesions produced hypertrophy in the dendritic arborization of pyramidal cells in parietal cortex. The results are consistent with the general findings that perinatal cortical injury in rats produces more severe behavioral and morphological effects than similar lesions in the second week of life and that cortical lesions around day 10 lead to an increase in cortical synaptogenesis.

Kolosova, L. I., A. D. Nozdrachev, et al. (2003). "[Effect of central axotomy of sensory neurones on the mechanoreception recovery in initial regeneration of the injured sciatic nerve in rats]." Ross Fiziol Zh Im I M Sechenova 89(5): 579-84.
 No apparent effect of lumbar dorsal rhizotomy performed simultaneously with the peripheral nerve injury, has been revealed on the triggering of regeneration of sensitive nerve fibers. Re-innervation of the foot skin by either decentralized regeneration of nerve fibers or those sustaining their connections with the central nervous system (CNS), has been shown to start 30 days after surgery. Using the recording of impulse activity of a single nerve fibre, the mechanical thresholds of decentralized regenerating receptors were found to be significantly higher as compared to the thresholds of the regenerating receptors sustaining their connections with the CNS. The findings suggest that afferent nerve fibers and mechanical receptors formed on the periphery, continue functioning after decentralization and sustain their regenerative capacity after injury. However, in marked contrast, the decrease in sensitivity of regenerating receptors is more pronounced.

Komiyama, T., Y. Nakao, et al. (2003). "A novel technique to isolate adult Schwann cells for an artificial nerve conduit." J Neurosci Methods 122(2): 195-200.
 The use of an artificial nerve conduit containing viable Schwann cells (SCs) is one of the most promising approaches to repair nerve injuries. Obtaining a large number of viable SCs in a short period is demanded for the clinical use of this technique. However, the previous methods using mitogens are not clinically acceptable, and other methods that do not require mitogens, failed to isolate adult SCs effectively or required a long period of time. In this study, we have developed a novel technique to isolate SCs from adult rat peripheral nerves for an artificial nerve conduit without mitogens, which has produced a total number of 1.21 x 10(5) cells per mg, with an average purity of 93.0+/-0.58% at 21 days in vitro. The Bottenstein-Sato (BS) medium used in this study, had originally been developed for oligodendrocyte culture, but here it is shown to have an effect on SC proliferation and survival. By changing fetal bovine serum (FBS) concentrations from 0 to 10% serially, SCs could be isolated maximally from the predegenerated nerves while suppressing fibroblast overgrowth. The combination of this technique and the altered medium promoted the migration and proliferation of SCs selectively by utilizing the supporting cells of SCs instead of discarding them by changing the culture dishes and media.

Koshima, I., Y. Nanba, et al. (2003). "Deep peroneal nerve transfer for established plantar sensory loss." J Reconstr Microsurg 19(7): 451-4.
 Patients with established or irreversible plantar sensory loss often have normal sensation on the dorsal aspect of the foot, due to an intact deep peroneal nerve. A new method of deep peroneal nerve transfer is proposed for repair of plantar sensory loss caused by extensive nerve gaps or high-level lesions of the posterior tibial nerve. Two cases in which this technique was used are described. The surgical technique is relatively easy, with a short operating time, rapid nerve regeneration after surgery, accurate sensory recovery, and minimal donor-site morbidity with sensory loss only on the first web space of the foot.

Koshimune, M., K. Takamatsu, et al. (2003). "Creating bioabsorbable Schwann cell coated conduits through tissue engineering." Biomed Mater Eng 13(3): 223-9.
 Enormous effort has been devoted to the generation of a synthetic guidance conduit for nerve repair instead of utilizing autograft. Several studies show neural guidance conduit is more effective when coated with Schwann cells. In this study, we synthesized bioabsorbable conduit consist of L-lactide and epsilon-caprolactone which was useful clinically and examined adhesion of Schwann cells to bioabsorbable conduits. In vivo studies were done in which these polymer conduits coated with Schwann cells were implanted across a 12 mm gap in the rat sciatic nerve. Silicone conduits were implanted across the same gap as control. At 12 weeks, axonal regeneration was observed in the midconduit region of these polymer conduits and was not in control. This study assesses the feasibility of a tissue engineering approach to constructing bioabsorbable conduits coated with Schwann cells.

Kotulska, K., J. Lewin-Kowalik, et al. (2003). "Bcl-2 deficiency deprives peripheral nerves of neurotrophic activity against injured optic nerve." J Neurosci Res 73(6): 846-52.
 Optic nerve injury leads to retinal ganglion cell apoptosis, thus preventing fiber regeneration. Peripheral nerve grafts are known to promote survival and regeneration in injured adult mammalian central nervous system, including optic nerve, but the mechanisms of their activity remain unclear. It is likely that they attenuate the apoptotic cascade triggered by axotomy in retinal ganglion cells. The aim of this work was to examine the role of the antiapoptotic gene bcl-2 in the optic nerve regeneration induced by such grafts. Experiments were carried out on bcl-2-deficient and wild-type mice. We have reported previously that predegeneration markedly enhances neurotrophic activity of peripheral nerve grafts, so we applied both predegenerated and non-predegenerated implants to the transected optic nerves. We studied the neurotrophic effects of bcl-2-deficient grafts on wild-type and bcl-2 knock-out optic nerves, as well as wild-type grafts on both strains of mouse optic nerves. After application of fluorescent dye to the end of the graft, we counted the stained retinal ganglion cells. Predegenerated wild-type grafts promoted survival and outgrowth of retinal ganglion cells axons in both types of mice. By contrast, non-predegenerated and predegenerated bcl-2-deficient grafts induced little or no regeneration in the optic nerves. These results indicate that the lack of bcl-2 gene does not deprive retinal ganglion cells of their regenerative potential. At the same time, we found that bcl-2 knock-out dispossesses peripheral nerves of their neurotrophic activity.

Koussoulakos, S., L. H. Margaritis, et al. (2003). "Quantitative estimation of HRP-labeled sensory and motor neurons during nerve-dependent and nerve-independent periods of urodele limb regeneration." Izv Akad Nauk Ser Biol(4): 405-15.
 The relationship between urodele regeneration and possible regeneration in mammalian prospects is hard to evidence, but the idea of possible regeneration of neural elements in people is an area of potential clinical importance that is under investigation. One of the great challenges of the future is to understand enough about the basic biology of animal regeneration and to use it for the betterment of the mankind. It is well established that the initial stages of urodele limb regeneration depend on the presence of intact nerve fibres connected to their cell bodies. The nerve fibres severed at the limb amputation level, regrow and invade the blastema, providing blastema cells with indispensable factors. These factors are elaborated within the neuron perikarya and transported via their axons to the blastema. Numerous studies have been so far performed and have elucidated the quantitative relationships between nerve fibres and limb regeneration. However, there are no reports dealing with the individual nerve cells at work. The aim of the present investigation was to analyse the quantitative participation and qualitative distinction of nerve cells innervating regenerating parts of the urodele limb and their possible interrelationship with the nerve-dependent and nerve-independent periods of regeneration. The cells under study are housed in the dorsal ganglia (sensory neurons) and in the ventral aspect of the spinal cord grey matter (motor neurons). As a means of visualizing the direct implication of these neurons during various regeneration periods, the enzyme horseradish peroxidase was chosen. A total of 34 animals were used, 21 experimental and 13 controls, in order to study labeled nerve cell fluctuations. The results are summarized as follows: (a) The first nerve cells incorporating HRP within 5 days post amputation are found in the dorsal ganglia. Motor neurons in the grey matter are labeled within 7 days. (b) The number of labeled perikarya increases during the nerve-dependent regeneration period (0-21 dpa). The percentage of implicated sensory neurons exceeds that found in the control series. (c) During the next, nerve-independent period, the number of participating labeled neurons decreases gradually. Such fluctuations in the number of labeled neurons might represent the metabolic status of these cells in their effort to provide the blastema cells with the factors needed at the appropriate time. The current findings support previous observations that the periods of dependence and independence of urodele limb regeneration from the integrated control of brachial nerves reflect changes in the metabolism of individual sensory and motor neurons.

Kozorovitskiy, Y. and E. Gould (2003). "Adult neurogenesis: a mechanism for brain repair?" J Clin Exp Neuropsychol 25(5): 721-32.
 It is now generally accepted that new neurons are added to the adult mammalian brain. This raises the possibility that naturally occurring neurogenesis may be useful for repairing the damaged adult brain. Indeed, several studies have shown that damage to the adult brain can stimulate reparative neurogenesis. However, the production of new neurons is only one of several steps necessary to restore damaged neural circuits to their original state. Studies carried out on intact animals have identified several conditions that affect the production and survival of new neurons in adult brains. This review considers the evidence for compensatory neurogenesis in the adult mammalian brain with a view toward applying information from the undamaged brain to studies of regeneration.

Kudlachev, A. V. and V. A. Otellin (2003). "[Perspectives for the clinical application of the results of current neuromorphological studies of the optical nerve lesions and atrophies]." Morfologiia 123(3): 94-102.
 The review presents the analysis of advances in fundamental studies of the optic nerve regeneration and degeneration mechanisms. It is concluded that current experimental morphological investigations of mechanisms of pathogenesis and sanogenesis of the optic nerve atrophies are developing in several major directions. These include: 1) development of techniques for restoration of the integrity of the optic nerve stem, including those that use peripheral nerve grafts; 2) development of measures to decrease the retinal ganglionic cell (RGC) response to injury and to stimulate RGC repair processes; 3) search for the ways for axon growth stimulation in lesioned and undamaged RGC; 4) usage of RGC apoptosis inhibitors; 5) grafting of embryonic retina. Results of the experimental studies are evaluated in the context of their possible application in clinical practice.

Kuntzer, T., M. Dunand, et al. (2003). "Phenotypic expression of a Pro 87 to Leu mutation in the connexin 32 gene in a large Swiss family with Charcot-Marie-Tooth neuropathy." J Neurol Sci 207(1-2): 77-86.
 BACKGROUND: The clinical manifestations of CMTX have been well described but the natural history has not yet been studied in detail. We studied phenotype variability in a family with a Pro 87 to Leu mutation of the connexin 32 (Cx32) gene. METHODS: A total of 32 family members, of which 19 patients were affected, underwent clinical, electrophysiological, and genetic studies. RESULTS: Onset was in the second decade. Clinical features were similar in both sexes when quantitative scores were compared, but more males had a steppage gait and skeletal deformities. All adult patients had a predominant involvement of the thenar muscles. The median values of nerve conduction velocities (NCVs) were not statistically different in men and in women. The correlation coefficients were low between motor NCVs within the same extremities, indicating nonuniform slowing between nerves, the ulnar nerve being the least affected. When disability was rated, a strong correlation was seen in male patients between severity of motor axonal loss and duration of the disease. The main pathological features were axonal loss, clusters of regenerating fibers and paranodal demyelination, the hallmark of a Schwann cell pathology. CONCLUSIONS: Our data support the hypothesis that clinical disability in CMTX is caused by loss of large myelinated axons in men. Furthermore, this study shows that the nerves are not uniformly affected in terms of axonal loss. Preventing axonal degeneration and promoting axonal regeneration in the most affected nerves might be the best therapeutic approaches to ameliorate disability in CMTX.

Kurihara, H., H. Shinohara, et al. (2003). "Neurotrophins in cultured cells from periodontal tissues." J Periodontol 74(1): 76-84.
 We review the basic functions of neurotrophins and their receptors and discuss the expression and functions of neurotrophins and their specific receptors based on recent data using cultured cells from human periodontal tissues. Neurotrophins, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) play crucial roles in the differentiation and survival of neural cells. Neurotrophins activate 2 different receptor classes: the tropomyosin-related kinase (Trk) family of receptor tyrosine kinases (TrkA, TrkB, and TrkC) and the p75 receptor, a member of the tumor necrosis factor receptor superfamily. Neurotrophins regulate both cell death and cell survival through activations of Trk receptors and/or p75 neurotrophin receptor. It has been reported that neurotrophins are also produced from non-neuronal cells, such as leukocytes, osteoblasts, or fibroblasts, and act in many other ways on non-neuronal cells. Neurotrophin expression during bone fracture healing is especially interesting, and neurotrophins are now implicated in hard tissue regeneration. It is well known that neurotrophins and their receptors are expressed in tooth development. Recent studies have found that neurotrophins and Trk receptors are expressed in mouse osteoblastic cell lines. Human periodontal ligament cells, human gingival fibroblasts, and human gingival keratinocytes expressed mRNA for NGF and TrkA. The secretion of bioactive NGF peptides from human periodontal ligament cells and human gingival keratinocytes was confirmed by bioassay using PC12 cells (rat adrenal pheochromocytoma cells). The expression of NGF and TrkA.mRNA was regulated by interleukin (IL)-1beta. NGF increased DNA synthesis and expressions of mRNA for bone-related proteins, alkaline phosphatase, and osteopontin in human periodontal ligament cells. Neurotrophins and Trk receptors expressed in human periodontal tissue may contribute to regeneration as well as innervation of periodontal tissue through local autocrine and paracrine pathways. Recent data suggest that some functions of neurotrophins and Trk receptors relate to periodontal disease and periodontal tissue regeneration. However, in vivo studies will be required to clarify the roles of neurotrophins and their receptors, including p75, in periodontal disease and periodontal tissue regeneration.

Kvist, M., N. Danielsen, et al. (2003). "Effects of FK506 on regeneration and macrophages in injured rat sciatic nerve." J Peripher Nerv Syst 8(4): 251-9.
 Effects of FK506 [5.0 mg/kg body weight (BW), subcutaneous, daily] on nerve regeneration and presence of macrophages in lesioned rat sciatic nerves were studied. Models of autologous nerve graft or a nerve crush lesion were used and regeneration was evaluated by immunocytochemistry (also used to detect ED1/ED2 macrophages) and sensory pinch reflex test, respectively. Treatment with FK506 did not increase regeneration distance or regeneration rate in the autologous nerve grafts. However, regeneration distances after nerve crush were significantly longer following treatment with FK506. The number of macrophages (ED1/ED2) in nerve grafts increased over time, but treatment with FK506 had limited effects only in the presence of ED2 macrophages. Present and previously published studies may imply that there is a time-related and type-of-injury-related profile of FK506's pro-regenerative effect.

Lambert, C., A. M. Landau, et al. (2003). "Fas-beyond death: a regenerative role for Fas in the nervous system." Apoptosis 8(6): 551-62.
 Fas (CD95, APO-1), a member of the TNF superfamily, is a prototypical "death receptor" which transduces apoptotic signals in a variety of cell types. However, cell death is not the only possible outcome of Fas signalling. Fas engagement by Fas Ligand can also trigger proliferation or differentiation, promote tumour progression and angiogenesis, and induce cytokine secretion and integrin expression. Recently, we have reported that Fas engagement induces a potent regenerative response in sensory neurons in vitro, and enhances peripheral nerve regeneration in vivo. In contrast, other types of neurons, notably motoneurons, are acutely sensitive to Fas-induced apoptosis. Here, we review the literature on non-apoptotic Fas signalling pathways, and discuss the potential roles, molecular mechanisms, and regulators of Fas signalling in the nervous system.

Lambiase, A., L. Manni, et al. (2003). "Clinical application of nerve growth factor on human corneal ulcer." Arch Ital Biol 141(2-3): 141-8.
 Nerve growth factor (NGF) is a neurotrophic and immunomodulatory factor contributing of the control of cutaneous morphogenesis, wound healing and inflammatory responses. Following the evidence that topical administration of NGF leads to healing of human corneal ulcers, we investigate the therapeutic action of NGF on immune and/or autoimmune cutaneous ulcers. We found that 1-10 micrograms of highly purified murine NGF dissolved in 50 microliters of physiological solution and topically applied to skin ulcer leads, after 4-12 weeks of daily treatment (depending on the size and depth of the lesion) to complete healing of the ulcer. Thus, NGF was able to promote complete repair in human skin and corneal ulcers which were poorly or non-responsive to conventional topical and systemic treatments. No side effects were observed and a follow up after 4 months showed no signs of relapse. These findings indicate that failure of cutaneous tissues to produce sufficient amounts of NGF might represent a prominent mechanism implicated in the clinical manifestation of ocular ulcers.

Lancelotta, M. P., R. N. Sheth, et al. (2003). "Severity and duration of hyperalgesia in rat varies with type of nerve lesion." Neurosurgery 53(5): 1200-8; discussion 1208-9.
 OBJECTIVE: To learn how lesions with differing capacity for nerve regeneration affect the severity and duration of hyperalgesia in an animal model of neuropathic pain. METHODS: Three groups of rats were studied: 1). L5 nerve root crush (favorable for regeneration); 2). L5 root ligation and section; and 3). sham-operated group. An experimenter who did not know the rats' groups tested the animals for hyperalgesia to mechanical and cold stimuli. RESULTS: Measures of adverseness of mechanical and cooling stimuli for the crush group and ligation/cut groups were significantly higher than for the sham-operated group (P < 0.001 for both) for the first 30 days after lesioning. By 40 days, the crush group recovered from mechanical hyperalgesia, whereas the ligation/cut group continued to have significant hyperalgesia. At this time, both lesion groups displayed hyperalgesia to the cooling stimulus (P < 0.001), but the hyperalgesia in the ligation/cut group was significantly greater (P < 0.01). No recovery from cooling hyperalgesia was evident during the 54-day period of observation. Histological studies of the sciatic nerve indicated higher numbers of regenerating fibers in the crush group compared with the ligation/cut group. CONCLUSION: This study demonstrates that axotomy, regardless of how it is induced, produces hyperalgesia to both mechanical and cold stimuli. However, the lesion that favors regeneration is associated with earlier signs of recovery from mechanical hyperalgesia and less severe signs of cooling hyperalgesia. The data support the hypothesis that inputs from the injured afferents play an ongoing role in neuropathic pain from nerve injury. Nerve ligation induces more severe and more sustained behavioral signs of pain than nerve crush.

Landi, F., L. Aloe, et al. (2003). "Topical treatment of pressure ulcers with nerve growth factor: a randomized clinical trial." Ann Intern Med 139(8): 635-41.
 BACKGROUND: The prevalence of pressure ulcers of the foot is a major health care problem in frail elderly patients. A pressure sore dramatically increases the cost of medical and nursing care, and effective treatment has always been an essential nursing concern. Management options for pressure ulcers include local wound care; surgical repair; and, more recently, topical application of growth factors. OBJECTIVE: To examine the effects of topical treatment with nerve growth factor in patients with severe, noninfected pressure ulcers of the foot. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Teaching nursing home of Catholic University of the Sacred Heart, Italy. PATIENTS: 36 persons with pressure ulcers of the foot. INTERVENTION: 18 patients received nerve growth factor treatment, and 18 patients received only conventional topical treatment. MEASUREMENTS: The course of the ulcers during follow-up was evaluated by tracing the perimeter of the wound onto sterile, transparent block paper and determining the stage. RESULTS: At baseline, the treatment and control groups did not differ across demographic variables, clinical characteristics, and functional measures. The mean area (+/-SD) of the ulcers was 1012 +/- 633 mm2 in the treatment group and 1012 +/- 655 mm2 in the control group (P > 0.2). The average reduction in pressure ulcer area at 6 weeks was statistically significantly greater in the treatment group than in the control group (738 +/- 393 mm2 vs. 485 +/- 384 mm2; P = 0.034). CONCLUSION: Topical application of nerve growth factor may be an effective therapy for patients with severe pressure ulcers.

Lanzetta, M., A. Gal, et al. (2003). "Effect of FK506 and basic fibroblast growth factor on nerve regeneration using a polytetrafluoroethylene chamber for nerve repair." Int Surg 88(1): 47-51.
 Peripheral nerve repair can be accomplished by using a polytetrafluoroethylene tubular chamber to guide nerve healing and regeneration. In this study, we delivered basic fibroblast growth factor (bFGF) into the chamber for sciatic nerve repair in rats. In addition, the animals were given systemically 1 mg/kg/day FK506 (tacrolimus), a potent immunosuppressant with neurotrophic properties. Nerve regeneration was evaluated by means of a nociceptive test and a grasping test starting 2 weeks postoperatively. Animals that received bFGF and FK506 showed a significantly faster recovery from injury than did the control group. Morphometric analysis at 3 months showed no difference between the two groups in total number of axonal fibers, fiber diameter, fiber density, and myelin:axon ratio. We conclude that the combination of bFGF and low dose FK506 enhances nerve healing in this animal model by accelerating early regrowth but has no effect on the final outcome.

Lee, A. C., V. M. Yu, et al. (2003). "Controlled release of nerve growth factor enhances sciatic nerve regeneration." Exp Neurol 184(1): 295-303.
 Based on previous studies demonstrating the potential of growth factors to enhance peripheral nerve regeneration, we developed a novel growth factor delivery system to provide sustained delivery of nerve growth factor (NGF). This delivery system uses heparin to immobilize NGF and slow its diffusion from a fibrin matrix. This system has been previously shown to enhance neurite outgrowth in vitro, and in this study, we evaluated the ability of this delivery system to enhance nerve regeneration through conduits. We tested the effect of controlled NGF delivery on peripheral nerve regeneration in a 13-mm rat sciatic nerve defect. The heparin-containing delivery system was studied in combination with three doses of NGF (5, 20, or 50 ng/mL) and the results were compared with positive controls (isografts) and negative controls (fibrin alone, NGF alone, and empty conduits). Nerves were harvested at 6 weeks postoperatively for histomorphometric analysis. Axonal regeneration in the delivery system groups revealed a marked dose-dependent effect. The total number of nerve fibers at both the mid-conduit level and in the distal nerve showed no statistical difference for NGF doses at 20 and 50 ng/mL from the isograft (positive control). The results of this study demonstrate that the incorporation of a novel delivery system providing controlled release of growth factors enhances peripheral nerve regeneration and represents a significant contribution toward enhancing nerve regeneration across short nerve gaps.

Lehnert, M., W. I. Steudel, et al. (2003). "Histochemical alterations of re-innervated rat extensor digitorum longus muscle after end-to-end or graft repair: a comparative histomorphological study." J Anat 203(1): 21-9.
 Changes in the histochemical profile of 43 rat extensor digitorum longus muscles undergoing de-innervation and re-innervation were recorded. Assessment of fibre type composition and muscle fibre cross-sectional area was performed at 15, 30, 90 and 180 days post operative (p.o.) after either primary end-to-end repair or autologous graft repair of the common peroneal nerve (n = 5 per time point and type of repair). The size and histochemical profile of single muscle fibres were analysed by computer-assisted quantification on the basis of their myofibrillar ATPase (pH 4.3) and succinate dehydrogenase (SDH) activities in serial, whole-muscle cross-sections. Accordingly, four muscle-fibre types could be functionally identified: (1) slow oxidative (SO, type I); (2) fast-oxidative glycolytic (FOG, type IIA); (3) fast glycolytic (FG, type IIB); and (4) succinate dehydrogenase intermediate (SDH-INT). At 15 days following end-to-end repair, the SDH-INT muscle fibre type was observed. By contrast, 15 days following graft repair, no changes in fibre type composition were observed (vs. control). At 30 days p.o. in the group that received end-to-end repair, type SDH-INT reached its maximum and was significantly higher than in the group that underwent graft repair. At 90 days p.o., the amount of SDH-INT fibres declined after end-to-end repair, but it was still significantly higher than in the group treated with a nerve graft. The increase of the SDH-INT fibre type was mirrored by a proportional disappearance of FG and FOG fibres. These changes were time-dependent, not reversible at 180 days p.o and largely blunted after nerve graft. Muscle-fibre size decreased at 15 and 30 days after both types of nerve repair. This decrease was transient and reversible within 90 days p.o. These findings reflect the fact that the reorganization of the histochemical profile in re-innervated muscles is both time dependent and long lasting. The degree of this reorganization is significantly higher after end-to-end repair than after graft repair.

Leis, A. A., J. A. Lancon, et al. (2003). "Retrograde regeneration following neurotmesis of the ulnar nerve." Muscle Nerve 28(4): 512-4.
 A 41-year-old woman experienced a gunshot wound to the forearm with neurotmesis of the ulnar nerve. Surgery 9 months later revealed a neuroma-in-continuity in the midforearm. Intraoperative nerve stimulation failed to elicit direct nerve responses or motor responses from the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles. However, neurotonic discharges in response to mechanical irritation of the neuroma were recorded in the FDI, but not the ADM. Surprisingly, after resecting the ulnar nerve distal to the neuroma, neurotonic discharges were still elicited in the FDI following perturbation of the neuroma. Moreover, neurotonic discharges were elicited during ulnar nerve resection 2 cm proximal to the neuroma. No anastomoses or anomalous branches were noted. The findings suggest that regenerating fibers did not reach the FDI through the distal nerve segment. Rather, we speculate that nerve fibers regenerating at random, or impeded by scar tissue, contacted the proximal nerve portion, at which point growth became polarized in a retrograde direction. Retrograde regeneration may have proceeded to a branch point in the forearm (possibly an undetected anomalous branch or fibrous adhesion), where growth of regenerating fibers extended outward into surrounding damaged tissue planes before redirecting distally to reach the FDI.

Leszczynsk