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PubMed2003

Regeneration of sciatic nerves of adult rats induced by extracts from distal stumps of pre-degenerated peripheral nerves.

Despite numerous experimental and clinical attempts to reconstruct injuries of peripheral nerves, the methods developed until now have not been sufficiently effective. We examined the influence of extracts (postmicrosomal fractions) obtained from non-pre-degenerated or 7-day-pre-degenerated distal segments of peripheral nerves on the regeneration of injured sciatic nerves of male adult rats. The extracts were introduced to the site of injury with autologous connective tissue chambers filled with fibrin. Reference groups were treated with brain-derived neurotrophic factor (BDNF) or fibrin only. We examined DiI-labeled motoneurons, toluidine blue-labeled myelinated fibers in the mid-part of the chambers, and AChE-positive nerve endings to assess the regeneration intensity. In addition, the length of fibers regrowing within the chambers was measured. We found that extracts obtained from distal stumps of 7-day-pre-degenerated peripheral nerves enhanced nerve regeneration as strongly as BDNF.

Acetylcholinesterase↗
PubMed2002

Restoration of upper extremity function after peripheral nerve injuries.

These days injuries to the peripheral nerves of the upper extremity that necessitate total or partial lesion are very common in the household and working environment. With regard to the majority of these injuries, not only plastic surgeons or neurosurgeons must have knowledge of their correct treatment, but general surgeons as well. The principles of reconstruction of the peripheral nerves of the upper extremity are described. The authors refer to immediate and delayed nerve repair, free nerve grafting, free vascularised nerve grafting, tendon transfer for a paralyzed hand, pedicled muscle transfer, functioning free muscle transplantation and neurotization.

Arm↗
PubMed2003

Secreted glycoprotein myocilin is a component of the myelin sheath in peripheral nerves.

The structure of the myelin sheath in peripheral nerves requires the expression of a specific set of proteins. In the present study, we report that myocilin, a member of the olfactomedin protein family, is a component of the myelin sheath in peripheral nerves. Myocilin is a secreted glycoprotein that forms multimers and contains a leucine zipper and an olfactomedin domain. Mutations in myocilin are responsible for some forms of glaucoma, a neurodegenerative disease that is characterized by a continuous loss of optic nerve axons. Myocilin mRNA was detected by Northern blotting in RNA from the rat sciatic and ophthalmic nerves. By one- and two-dimensional gel electrophoresis of proteins from the rat and human sciatic nerves, myocilin was found to migrate at an isoelectric point (pI) of 5.2-5.3 and a molecular weight of 55-57 kDa. Immunohistochemistry showed immunoreactivity for myocilin in paranodal terminal loops of the nodes of Ranvier and outer mesaxons and basal/abaxonal regions of the myelin sheath. Double-labeling experiments with antibodies against myelin basic protein showed no overlapping, while overlapping immunoreactivity was observed with antibodies against myelin-associated glycoprotein. The expression of myocilin in the sciatic nerve became detectable at postnatal day (P) 15 and reached adult levels at P20. No or minor expression of myocilin mRNA was found in brain, spinal cord, and optic nerve. mRNA of myocilin was detected in schwannoma cells in situ, but at considerably lower levels than in myelinated nerves. Myocilin might significantly contribute to the structure of the myelin sheath in peripheral nerves.

Aging↗
PubMed2000

The future of peripheral nerve neurostimulation.

Electrical stimulation of selected peripheral nerves for treatment of intractable pain has been used inconsistently over the past 30 years due to difficulties in clarifying appropriate indications, utilizing approved device technology, and standardizing the surgical techniques. Circumferential electrodes treating mononeuropathies have given way to paddle electrode techniques and, most recently, the application of percutaneous wire electrode methods will allow for minimally invasive peripheral nerve stimulation for certain intractable CRPS and other painful monoeuropathies.

Electric Stimulation Therapy↗
PubMedDate not supplied

Effects of intraoperative hyperthermia on peripheral nerves: neurological and electrophysiological studies.

The tolerance of peripheral nerves to heat may limit the heat dose which can be applied to tumours. This may be particularly important in intraoperative hyperthermia (IOHT) for pelvic and retroperitoneal tumours. Furthermore the effects of hyperthermia alone must be known before its effects can be assessed in combination with irradiation. In this study injury to sciatic nerves was evaluated in 30 beagle dogs for 1 year following IOHT. IOHT was performed using a water circulating hyperthermia device with multichannel thermometry system. Neurological and electrophysiological examinations were done before, during and after IOHT treatment. Electrophysiological examinations showed a significant decrease in sciatic nerve conduction velocity and potential amplitude immediately after 60 min of heating for all temperatures. The greatest decrease in conduction velocity was observed for a temperature of 45 degrees C. Full recovery of nerve conduction velocity was observed 3 weeks following hyperthermia for all dogs except for those exposed to 45 degrees C. Neurological findings correlated with electrophysiological results. All five dogs which had nerve exposed to 45 degrees C for 60 min had severe neurological changes, with recovery taking place between 3 and 11 months after treatment. Based on these results it appears that temperatures to the peripheral nerve exceeding 44 degrees C for 1 h are likely to cause significant, but not necessarily permanent, nerve injury.

Action Potentials↗
PubMed1982

Preparation of cell-free extracellular matrix from human peripheral nerve.

The extracellular matrix of human peripheral nerve, which is mainly basement membrane and fibrillar collagen, has been prepared by a procedure involving extensive detergent extraction of isolated endoneurium and perineurium obtained from various nerves. The ultrastructure of the isolated nerve extracellular matrix was indistinguishable from that seen in sections of intact nerve, indicating that the extraction procedure preserved the morphological integrity of these connective tissue components. The amino acid and carbohydrate compositions of the nerve extracellular matrix preparations were typically collagenous in nature containing a high content of glycine, proline, 4-hydroxyproline, and alanine and significant amounts of lysine and hydroxylysine. The preparations contained virtually no 3-hydroxyproline and low content of glucose and galactose compared to pure basement membranes, indicating that interstitial rather than basement membrane collagens predominated. This preparation appears well-suited to both the ultrastructural and biochemical study of the extracellular matrix of peripheral nerve.

Cell Fractionation↗
PubMed1996

Glucose transporters in rat peripheral nerve: paranodal expression of GLUT1 and GLUT3.

Peripheral nerve depends on glucose oxidation to energize the repolarization of excitable axonal membranes following impulse conduction, hence requiring high-energy demands by the axon at the node of Ranvier. To enter the axon at this site, glucose must be transported from the endoneurial space across Schwann cell plasma membranes and the axolemma. Such transport is likely to be mediated by facilitative glucose transporters. Although immunohistochemical studies of peripheral nerves have detected high levels of the transporter GLUT1 in endoneurial capillaries and perineurium, localization of glucose transporters to Schwann cells or peripheral axons in vivo has not been documented. In this study, we demonstrate that the GLUT1 transporter is expressed in the plasma membrane and cytoplasm of myelinating Schwann cells around the nodes of Ranvier and in the Schmidt-Lanterman incisures, making them potential sites of transcellular glucose transport. No GLUT1 was detected in axonal membranes. GLUT3 mRNA was expressed only at low levels, but GLUT3 polypeptide was barely detected by immunocytochemistry or immunoblotting in peripheral nerve from young adult rats. However, in 13-month-old rats, GLUT3 polypeptide was present in myelinated fibers, endoneurial capillaries, and perineurium. In myelinated fibers, GLUT3 appeared to be preferentially expressed in the paranodal regions of Schwann cells and nodal axons, but was also present in the internodal aspects of these structures. The results of the present study suggest that both Schwann cell GLUT1 and axonal and Schwann cell GLUT3 are involved in the transport of glucose into the metabolically active regions of peripheral axons.

Animals↗
PubMed1994

Efficacy of pretransection of peripheral nerve for promoting the survival of cografted chromaffin cells and recovery of host dopaminergic fibers in animal models of Parkinson's disease.

Nerve growth factor (NGF) concentration in the distal stump of the transected peripheral nerve has been shown to increase more than 20 times one day after transection. We performed adrenal medullary alone grafts or cografts of adrenal medulla and acutely transected or pretransected (24 h before) sciatic nerve into the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice, and compared the survival of chromaffin cells and the recovery of the host-intrinsic dopaminergic fibers using tyrosine hydroxylase immunocytochemistry and high-performance liquid chromatography. We also performed peripheral nerve alone grafting (acutely transected or pretransected) for comparison. Adrenal medullary chromaffin cells cografted with pretransected sciatic nerve survived better than those in adrenal grafts alone or those cografted with acutely transected sciatic nerve. Host dopaminergic fiber recovery was also most prominent in mice cografted with pretransected peripheral nerve. Animals receiving grafts of peripheral nerve alone showed limited recovery of host dopaminergic fibers and the degree of recovery was lower than that of animals receiving cografts of adrenal medulla with pretransected peripheral nerve. We conclude that pretransected peripheral nerve enhanced the survival of cografted chromaffin cells and this increased survival led to promote the recovery of host-intrinsic dopaminergic fibers. This grafting procedure might be promising in application to patients with Parkinson's disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1981

Morphological observations of peripheral nerves by the scanning electron microscope.

In order to observe a normal peripheral nerve and a changed peripheral nerve by means of a scanning electron microscope, the present study was carried out. In the changed nerve fibers, they were enveloped by many processes of hypertrophied Schwann cells, and the processes of the Schwann cells seemed to make a pseudosyntitium-like structure with each other. From this finding, it was speculated that these Schwann cells seemed to follow the reverse process in the development of normal peripheral nerve fibers.

Animals↗
PubMed1993

Enhanced peripheral nerve regeneration by acidic fibroblast growth factor.

Transection of peripheral nerves may cause permanent denervation with paralysis and disability in humans and represents a challenging problem in microsurgery. Physiologic repair at increasing intervals after the acute phase of injury results in progressively worse recovery, emphasizing the importance of rapid and timely reinnervation to optimize endorgan viability. Despite recent advances in microsurgical techniques, imperfect reinnervation results in partial return of neuromuscular function, even in the mildest neuropraxias. Axonal repair of mature neurons involves a complex interaction of molecular events, suggesting that the presence of specific neuronotropic factors might enhance the regeneration process. Recombinant human fibroblast growth factor (FGF-1) has been shown to induce both rapid angiogenesis and neurogenesis through a synthetic conduit across a 15-mm surgical gap in the peripheral nerve of the rat. Evidence of newly formed neural structures was confirmed postoperatively by histological examination in a temporal fashion over a 24-week interval. Functional motor recovery of regenerated nerves was evaluated by determining the amplitude and latency of compound muscle action potentials in treated animals. Electrophysiology studies demonstrated consistent return of motor function in 43 and 57% of animals harboring an FGF-1 conduit at 8- and 24-week intervals, respectively. None of the control animals exhibited restoration of motor function. Collectively, these data suggest that FGF may serve as an important mediator of controlled growth during peripheral nerve regeneration.

Action Potentials↗
PubMed1997

Characterization of a 30-kDa peripheral nerve glycoprotein that binds laminin and heparin.

We have shown previously that a bovine peripheral nerve protein with a molecular mass of about 30 kDa binds laminin in blot overlay assay. In this paper, we have characterized this 30-kDa laminin-binding protein (LBP30). LBP30 was extracted from the crude bovine peripheral nerve membranes at pH 12 or by 0.5 M NaCl but not by 2% Triton X-100. LBP30 bound to heparin-Sepharose in the presence of 0.5 M NaCl. The results of lectin staining indicated that LBP30 contained both terminally sialylated and nonsialylated Ser/Thr-linked oligosaccharides. LBP30 bound laminin-2 as well as laminin-1 but not fibronectin or collagen type IV. When immobilized LBP30 was incubated with the crude peripheral nerve membrane extracts, all of the endogenous peripheral nerve laminin chain isoforms, the alpha1, alpha2, beta1, beta2, and gamma1 chains, were detected bound to LBP30. The binding of LBP30 to laminin was inhibited by heparin, heparan sulfate, dextran sulfate, or NaCl but was not affected significantly by chondroitin sulfate, dextran, or EDTA. Although LBP30 bound to laminin-1 denatured with SDS in a nonreducing condition, the binding was reduced drastically when laminin-1 was denatured with SDS in a reducing condition, suggesting that the binding of LBP30 is somewhat dependent on the high order structure of laminin-1. Immunohistochemical analysis demonstrated the broad distribution of LBP30 in the perineurium and endoneurium of bovine peripheral nerve. These results indicate that LBP30 is a laminin- and heparin-binding glycoprotein localized in the perineurium and endoneurium of bovine peripheral nerve.

Animals↗
PubMed1983

The peripheral nerve involvement in spinocerebellar degenerations.

We studies peripheral nerves electrophysiologically in 15 cases of spinocerebellar degenerations (SCD). Three patients showed abnormalities in 40% or more of the 13 items examined in this study. Two patients showed abnormalities in 20--40% of the items. Ten patients showed abnormalities in 20% or less of the items; six of them showed no abnormalities in any of the items. The incidence of abnormalities was slightly higher in the sensory nerve than in the motor nerve and was slightly higher in the peripheral areas than in the proximal areas in both the motor and sensory nerves. A high incidence of abnormalities was observed in cases of olivo-ponto-cerebellar atrophy (OPCA), the longer the history of the disease, the higher the incidence of abnormalities. This finding supports the idea that OPCA, not being only a single system, will develop into multiple system atrophy in a broad sense through rigidity and peripheral nerve disorders during a long course of the disease. Two patients with talipes cavus with muscular atrophy had peripheral nerve disorders.

Adult↗
PubMed1996

Is axonal sprouting able to traverse the conjunctival layers of the peripheral nerve? A behavioral, motor, and sensory study of end-to-side nerve anastomosis.

The repair of large peripheral nerve defects is not always possible, especially when the proximal stump is not available. In these cases, end-to-side nerve anastomosis has been proposed. In the present experiment, using the terminal branches of the rat brachial plexus, the authors studied behavioral responses after end-to-side nerve anastomoses using fibrin glue, 3 and 6 months after surgery. Rats were evaluated by results of a grasping test, a capsaicin test and a hot-plate test. The collected data demonstrated that there was no functional motor or sensory reinnervation after the end-to-side nerve anastomoses. The conjunctive layers of the peripheral nerve thus represented an effective barrier to reinnervation.

Anastomosis, Surgical↗
PubMed1984

[Benign tumors of the peripheral nerve sheaths].

Benign tumors from sheaths of peripheral nerves (25 neurolemmomas and 6 neurofibromas) were studied. The ultrastructural data presented attest to the principal differences between these tumors and the possibility of their differential diagnosis. The typical signs of tumor cells of neurilemmoma include numerous complicatedly interwoven processes not infrequently forming " pseudomesaxonal " structures, and the presence of permanent basal membrane. These signs indicate the histogenetic relationship of neurilemmoma with cells of the Schann sheath of the peripheral nerve ( lemmocytes ). Neurofibroma tumor cells were characterized by the presence of bipolar thin, long non-interwoven cytoplasmic processes with inconstant basal membrane, desmosome-like contacts between the processes, and pinocytic vesicles in the cytoplasm. The revealed ultrastructural signs indicate the histogenetic relationship of neurofibroma with cells of the perineurium of peripheral nerves.

Adolescent↗
PubMed2000

Peripheral nerve and neuromuscular allotransplantation: current status.

Some major peripheral nerve deficits in otherwise salvageable extremities are unreconstructable with autogenous nerve grafts because of their limited availability. Peripheral nerve allotransplantation has been attempted experimentally and clinically for more than a century. It is only since the advent of the immunophyllin-immunosuppressive agents (Cyclosporin A and FK506) that nerve regeneration across allografts has been comparable to that observed across autografts. Experimental studies have demonstrated excellent regeneration through nerve allografts with recipient CsA and FK506 immunosuppression given continuously and for limited periods. This permitted the development of a clinical trial. To date, seven patients received major nerve reconstructions with nerve allografts under temporary immunosuppression; six have had sensory recovery; three motor recovery; and one no recovery due to rejection. The experimental and clinical work will be reviewed and relevance to composite tissue allotransplantation discussed.

Animals↗
PubMed2007

Peripheral nerve stimulation and monitoring during operative procedures.

Monitoring of peripheral nerve function is important during the surgical treatment of peripheral nerve and plexus lesions, allowing for rapid assessment of the integrity of the roots, plexus, and nerves. The results of this monitoring assist the surgeon in the overall approach to treatment of these lesions. There are, however, many technical challenges to providing this neurophysiological information in an accurate and rapid fashion. This study assesses the equipment and techniques involved in intraoperative peripheral nerve monitoring and describes its use in the more common clinical scenarios.

Animals↗
PubMedDate not supplied

Development of a standardized peripheral nerve block procedure note form.

OBJECTIVES: Despite the tremendous growth of peripheral nerve blocks, no standard format exists to document their performance. Our objective was to create a peripheral nerve block form based on key elements of literature evidence and on our own group consensus. RESULTS: We describe the process and results of our multi-institutional effort to construct a standardized peripheral nerve block procedure form. CONCLUSION: A form was developed to help meet the medical, legal, and billing requirements of documentation consistent with the performance of peripheral nerve block.

Humans↗