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Results for “Peripheral Nerves”

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PubMed1970

Peripheral nerve function in chronic liver disease.

Peripheral nerve function has been studied in 50 patients with chronic liver disease. An increase in the latency or a reduction in the response amplitude of the evoked sensory potential of the median nerve was detected in 34 of the 50 subjects. This was in striking contrast to the paucity of neurological signs and symptoms suggestive of peripheral nerve damage seen in these patients. There was no evidence to show that alcohol was responsible for the neuropathy. Abnormalities in the excitability changes of sensory nerve during ischaemia were detected in seven of the 16 subjects whose distal sensory latencies were within normal limits. A critical evaluation of the hypotheses which have been postulated to account for the increased resistance of peripheral nerve to inactivation by ischaemia has been made. It is concluded that an increase of the permeability of the periaxonal diffusion barrier to K offers the most acceptable explanation for this phenomenon.

Adult↗
PubMed2001

Paraneoplastic anti-CV2 antibodies react with peripheral nerve and are associated with a mixed axonal and demyelinating peripheral neuropathy.

Subacute sensory neuronopathy with anti-Hu antibodies is the best-characterized paraneoplastic peripheral neuropathy associated with carcinoma. Anti-CV2 antibodies, another group of paraneoplastic antibodies, react with a 66-kd brain protein belonging to the family of Ulip/CRMP proteins. The manifestations associated with anti-CV2 antibodies include cerebellar degeneration, uveitis, and peripheral neuropathy. Some of these patients also have anti-Hu antibodies. We have compared the clinical, electrophysiological, and pathological characteristics of the peripheral neuropathy in 9 patients with anti-CV2 antibodies (3 of whom also had anti-Hu antibodies) and 12 patients with only anti-Hu antibodies. Data for patients with anti-Hu antibodies alone indicated subacute sensory neuronopathy. Patients with anti-CV2 antibodies had a mixed axonal and demyelinating sensory motor neuropathy that was sometimes superimposed on subacute sensory neuronopathy when both anti-CV2 and anti-Hu antibodies were present. Unlike anti-Hu antibodies, anti-CV2 antibodies reacted with peripheral nerve antigens, as shown by their ability to bind to a 66-kd protein in human and rat nerve on Western blot analysis and to immunolabel peripheral nerve axons and sensory neurons on immunohistochemical study.

Aged↗
PubMed2005

Peripheral nerve transplantation: the role of chemical acellularization in eliminating allograft antigenicity.

This study tests the hypothesis that a chemically acellularized peripheral nerve allograft is as immunologically inactive as a peripheral nerve isograft. Cellular and acellular sciatic nerves were transplanted from BALB/c into C57BL/6 mice. C57BL/6 sciatic nerves were also transplanted into C57BL/6 recipients as isograft controls. Fourteen days post-transplantation, recipient splenocytes were isolated, stimulated with donor alloantigens, and IL-2, IL-4, IL-5, and gamma-IFN production was quantified using the ELISPOT technique. Cellular peripheral nerve allografts stimulated robust Th1 and Th2 systemic immune responses, whereas acellular peripheral nerve allografts elicited a response that is comparable to or lower than that quantified following peripheral nerve isograft transplantation. Chemical acellularization of peripheral nerve allografts dramatically reduces the cellular and humoral immunologic responses. These data indicate that chemically acellularized peripheral nerve constructs are relatively non-antigenic and may be a readily available source of nerve for peripheral nerve reconstruction.

Animals↗
PubMed2000

Augmentative treatment of chronic deafferentation pain syndromes after peripheral nerve lesions.

Deafferentation pain syndromes developing after peripheral nerve lesions are difficult to treat. According to the follow-up (mean: 39.5 months) of 6 patients suffering from causalgic pain we will present our method of augmentative therapy in chronic neuropathic pain caused by peripheral nerve lesions, i.e., peripheral nerve stimulation (PNS), spinal cord stimulation (SCS) and chronic intrathecal opioid infusion. None of the patients showed intraoperative or follow-up complications. Evaluated by visual analogue scales all patients reported a good to excellent pain relief (75-100%). (1) Regarding the favourable long-term results of PNS, this method should be considered in cases of mononeuropathic pain syndromes. (2) Neuropathic pain syndromes which are not assignable to a singular nerve lesion, can often be managed effectively by SCS. (3) In contrast to the widespread opinion, deafferentation pain syndromes of central or peripheral origin can be treated satisfactorily by intrathecal opiate administration.

Adult↗
PubMed1987

Elongation of peripheral nerve and viscera containing smooth muscle.

Peripheral nerve, ureter, and small bowel will all elongate over a soft-tissue expander. Elongation of peripheral nerve serves as an effective alternative to nerve grafting both in selected clinical cases and in experimental settings. While canine ureter functions well with little morphologic change following elongation, the rabbit small bowel morphology and function are significantly altered after elongation through expansion.

Animals↗
PubMed2006

cDNA microarray analysis of cancer associated gene expression profiles in malignant peripheral nerve sheath tumours.

BACKGROUND: Malignant peripheral nerve sheath tumour (MPNST) is a highly aggressive malignancy that arises within peripheral nerves, and is associated with poor prognosis. Little is known about the underlying biology of MPNST, especially the mechanisms involved in cell proliferation, invasion, or escape from apoptosis. AIMS: To identify genes differentially expressed in MPNST compared with benign tumours, such as neurofibromas and schwannomas, by means of cDNA microarray analysis. METHODS: Six MPNST cases and five benign cases (three schwannomas and two neurofibromas) were analysed. RESULTS: Six genes (keratin 18, survivin, tenascin C, adenosine deaminase, collagen type VIa3, and collagen type VIIa1) were significantly upregulated in MPNST, whereas one gene, insulin-like growth factor binding protein 6, was downregulated in MPNST. Survivin and tenascin C expression was validated by reverse transcription polymerase chain reaction. Immunohistochemistry confirmed upregulation of survivin in MPNST at the protein level in six of eight cases compared with benign tumours. Tenascin C was also expressed at the invasive front and tumorous stroma in all MPNST cases. MPNST cells expressed tenascin C in four of nine cases. CONCLUSIONS: Survivin and tenascin C may be associated with the malignant potential of MPNST and could be considered as potential therapeutic targets.

Adult↗
PubMed1998

Peripheral nerve and transgene cells transplantation in the treatment of experimental neuropathy of SD rats.

PURPOSE: To observe whether optic nerve can regenerate by peripheral nerve transplantation and GDNF gene transfer. METHODS: Optic nerve was transected about 2 mm posterior to the eye to establish experimental models of optic neuropathy. Sciatic nerve was sutured to the sheath of injury optic nerve by a 10-0 nylon, pcDNA3-GDNF was smeared to the joint and injected to the vitreous cavity. The regenerated retinal ganglion cells axons were observed by HRP. The retina and optic nerve were observed by pathohistological methods. RESULTS: Some retinal ganglion cells with regenerated axons could be seen a week after transplantation with large cell bodies. The cells could be identified by HRP. The regenerated nerve fibers grew to the transplanted sciatic nerve. Then the number of retinal ganglion cells with regenerated axons increased with time going. Only a few regenerated retinal ganglion cells could be seen two months after transplantation. The large retinal ganglion cells were seen to have plenty of cytoplasms and be in an active state under electron microscope. Some nerve fibers could be seen in the joint. Sciatic nerve transplantation combined with GDNF gene therapy could increase the amount of retinal ganglion cells with regenerated axons compared with those without GDNF transgene. CONCLUSIONS: Optic nerve could regenerate by peripheral nerve transplantation and GDNF gene transfer.

Animals↗
PubMed1997

The role of magnetic resonance imaging in the management of peripheral nerve tumours.

Fourteen cases of peripheral nerve tumour which had been examined by MRI were reviewed. T1-weighted images showed the tumours to be of intermediate signal and T2-weighted images showed a high signal with some heterogeneity. These appearances are not specific to peripheral nerve tumours, although the diagnosis may be suggested if the lesion arises from a major nerve trunk. The association with a nerve trunk may be defined by MRI, thus assisting with surgical planning. Neurilemmomas, neurofibromas and malignant nerve sheath tumours could not be differentiated with certainty using MR alone. The MR features of lipofibromatous hamartoma are reported.

Adult↗
PubMed1978

Microsurgery of the peripheral nerve: a physiological approach.

Results with peripheral nerve injuries, which today still fall short of our goals, should intensify our efforts in this specialized field of microsurgery. We are living in an exciting era of functional reconstitution. Long gone are the times when a pink replanted digit or a successful free flap comprised the end-point of our surgical efforts. The direction from now on is toward achieving functional restoration by utilizing basic principles while armed with the unlimited potentials of reconstructive microsurgery. To this end we need the assistance and cooperation of other sciences since the enigma of the peripheral nerve can be deciphered only by a multidisciplinary approach.

Electrophysiology↗
PubMed1989

[Restoration of severed peripheral nerves].

The state of the art in restoration of severed peripheral nerves is outlined. Discussion of the prerequisites for an optimal nerve-repair such as intraneural anatomy of peripheral nerves (topography of nerves in cross-section), techniques for preparation of nerve stumps, lesions in continuity, precise rotational orientation, nerve-suture, interfascicular dissection and nerve-grafting, including harvesting of autologous nerve grafts and finally the postoperative management after restoration of peripheral nerves are discussed.

Humans↗
PubMed1998

Direct convective delivery of macromolecules to peripheral nerves.

OBJECT: Although many macromolecules have treatment potential for peripheral nerve disease, clinical use of these agents has been restricted because of limitations of delivery including systemic toxicity, heterogeneous dispersion, and inadequate distribution. In an effort to overcome these obstacles, the authors examined the use of convection to deliver and distribute macromolecules into peripheral nerves. METHODS: For convective delivery, the authors used a gas-tight, noncompliant system that provided continuous flow through a small silica cannula (inner diameter 100 microm, outer diameter 170 microm) inserted into a peripheral nerve. Increases in the volume of infusion (Vi) (10, 20, 30, 40, and 80 microl) of 14C-labeled (nine nerves) or gadolinium-labeled (two nerves) albumin were infused unilaterally or bilaterally into the tibial nerves of six primates (Macaca mulatta) at 0.5 microl/minute. The volume of distribution (Vd), percentage recovery, and delivery homogeneity were determined using quantitative autoradiography, an imaging program developed by the National Institutes of Health, magnetic resonance (MR) imaging, scintillation counting, and kurtosis (K) analysis. One animal that was infused bilaterally with gadolinium-bound albumin (40 microl to each nerve) underwent MR imaging and was observed for 16 weeks after infusion. The Vd increased with the Vi in a logarithmic fashion. The mean Vd/Vi ratio over all Vi was 3.7+/-0.8 (mean+/-standard deviation). The concentration across the perfused region was homogeneous (K=-1.07). The infusate, which was limited circumferentially by the epineurium, followed the parallel arrangement of axonal fibers and filled long segments of nerve (up to 6.8 cm). Recovery of radioactivity was 75.8+/-9%. No neurological deficits arose from infusion. CONCLUSIONS: Convective delivery of macromolecules to peripheral nerves is safe and reliable. It overcomes obstacles associated with current delivery methods and allows selective regional delivery of putative therapeutic agents to long sections of nerve. This technique should permit the development of new treatments for numerous types of peripheral nerve lesions.

Animals↗
PubMedDate not supplied

An explanation of axonal regeneration in peripheral nerves and its failure in the central nervous system.

Nerve fibres severed within peripheral nerves are able to regenerate and reinnervate the structures they formerly supplied. Most axons severed within the mammalian central nervous system (CNS) do not regenerate in this way. Regenerative axonal growth begins to occur in the CNS but ceases about two weeks after injury. Five earlier theories purporting to explain this difference are reviewed and found not to account satisfactorily for many experimental observations. A new hypothesis is advanced in which it is held that in order for regeneration to take place, the growing tips of the axons must be surrounded by extracellular fluid containing proteins (of specified identity) derived from the blood plasma. Such proteins are thought to be imbibed by the tips of the fibres and transported retrogradely to the neuronal cell-bodies. With this hypothesis it is possible to explain the success of axonal regeneration in peripheral nerves and its failure in the CNS. It is also possible to account for the exceptional circumstances in which axons do regenerate in the CNS. Various experiments are suggested for testing the validity of the new hypothesis.

Amphibians↗
PubMed1982

Increased polyunsaturated fatty acids in developing and regenerating peripheral nerve.

Characteristic fatty acids of peripheral nerve myelin are mainly saturated and monounsaturated. A marked increase of polyunsaturated fatty acids, particularly arachidonic acid, was found in endoneurial phosphatidylethanolamine of both developing and regenerating rat sciatic nerve, suggesting a close association between polyunsaturated fatty acids and peripheral nerve myelination.

Animals↗
PubMed1986

Evidence indicating trophic importance of IGF-I in regenerating peripheral nerves.

The mechanisms influencing regeneration of peripheral nerves are incompletely known, but growth factors are supposed to play a key role. In the present study, we demonstrate, with the aid of immunohistochemical methods, that somatomedin C (Sm-C/insulin-like growth factor I/IGF-I) rapidly increased from low to high concentrations, reaching peak values in 2 weeks, in regenerating sciatic nerves of adult rats. In addition, IGF-I was demonstrated extracellularly, never observed in the control nerves. Reactive Schwann cells appeared to be the major source for IGF-synthesis. Higher concentrations were seen in tubulated nerves as compared to sutured ones. It is proposed that IGF-I exerts important growth supporting effects on regenerating peripheral nerves.

Animals↗
PubMed2000

[Repair of traumatic lesions in peripheral nerves--introduction].

The reconstruction of traumatic lesions of peripheral nerves (PN) underwent the most significant improvement with the introduction of operating microscopes, microsurgical techniques and pertinent instruments, including microsutures. New information with respect to the pathophysiology of the degeneration and regeneration of peripheral nerves on a subcellular level also helped in the delineation of the rules and timing of optimal conditions for suturing. The present microtechnique seems to have reached its plateau with regard to capacity of available materials, technology and methodology. Despite this progress there is room for further improvement as addressed in this presentation. In this part of our work we would like to present a survey and analysis of the necessary theoretical knowledge of the basis of degeneration of a traumatized peripheral nerve at the level of molecular changes, as well as to indicate new technologies and materials. A detailed comparison of the classical method (microsuture) with the new technology (laser) has so far failed to demonstrate any significant difference. Therefore it appears necessary, when seeking advantages of the new methodology, to examine its application and not its quality, which will be the subject of the second part our work.

Humans↗
PubMed1989

Pathological studies of aberrant peripheral nerve bundles of spinal cords.

Aberrant peripheral nerve fiber bundles, i.e., masses of peripheral nerve fibers without perineural sheath cells, are found in the perivascular spaces of some spinal cords. The 514 spinal cords examined for these structures were separated into two groups; 507 spinal cords without definite necrotic lesions (group 1) and 7 spinal cords (group 2) with old necrotic lesions in which there were numerous aberrant peripheral never bundles (APNB). In group 1, APNB were found in 41.0% of spinal cords. The incidence was the same for both sexes and increased in proportion to age. APNB were found predominantly in the middle and lower thoracic segments. On the transverse sections, APNB were located mainly in the central gray matter and in the anterior median fissure. Ultrastructural and histochemical studies showed that the myelin in APNB was peripheral in origin. Serial sections showed continuity between APNB and nerve roots. In group 2 cases, APNB were diffusely distributed throughout the old necrotic lesions and not restricted to perivascular areas.

Adult↗
PubMed2000

Surgery for peripheral nerve and brachial plexus injuries or other nerve lesions.

The selection of patients who will benefit from peripheral nerve surgery continues to evolve. The evaluation of patients with peripheral nerve problems, and the indications and timing of surgery are reviewed. This includes patients with transections, lesions in continuity, entrapments, tumors, injection injuries, and birth palsies. The treatment outlined for patients with peripheral nerve and brachial plexus injuries is based on a comprehensive clinical and electrodiagnostic evaluation complemented by imaging studies. A systematic approach to the surgical management of these neural lesions has evolved at our institution, based in part on extensive experience with intraoperative recording of nerve action potentials (NAPs) and a resultant large number of referrals. Advanced microsurgical techniques including use of grafts have expanded the scope of peripheral nerve surgery. These advances coupled with intraoperative electrophysiologic measurements have improved outcomes.

Brachial Plexus↗
PubMed1997

[Intraoperative extra strong electrical stimulation in the treatment of peripheral nerve injury].

In order to enhance the therapeutic effectiveness of peripheral nerve injury, intraoperative extrastrong electrical stimulation was used in peripheral nerve surgery. In 16 cases of incomplete peripheral rnerve injuries or poorly regeneratedn erves, continuous intraoperative electrophysiological monitoring was used for guidance of neurolysis. Meanwhile, extrastong electrical stimulation was applied. The latency and amplitude before and after electrical stimulation were recorded and the extent of improrement was compared. In all cases, the latency and amplitude were improved after neurolysis and electrical stimulation. Clinical follow-up also showed that the function of corresponding innorvated muscle was improved. Continuous intraoperative extrastrong electrical stimulation could be used as an practical measure to increase the effectiveness of peripheral nerve treatment.

Adolescent↗