Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Peripheral Nerves”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources
PubMed1983

Central and peripheral nerve conduction in thyroid dysfunction: the influence of L-thyroxine therapy compared with warming upon the conduction abnormalities of primary hypothyroidism.

1. The latencies of the visual evoked responses, indices of central nerve conduction, and peripheral nerve conduction were slowed in patients with primary hypothyroidism compared with controls. 2. In thyrotoxic patients, there was no change in the latencies of the visual evoked responses and peripheral nerve conduction compared with the control group. 3. The abnormalities seen in hypothyroidism were reversed by L-thyroxine therapy. 4. Warming untreated hypothyroid patients significantly improved both central and peripheral nerve conduction. 5. The conduction delay found in hypothyroidism is to a large extent dependent upon a subnormal body temperature.

Evoked Potentials, Visual↗
PubMed1998

Transcutaneous electrical nerve stimulation: effect on peripheral nerve conduction, mechanical pain threshold, and tactile threshold in humans.

OBJECTIVES: To investigate the effect of different transcutaneous electrical nerve stimulation (TENS) parameters on nerve conduction in the human superficial radial nerve and on peripheral mechanical pain threshold (MPT) and tactile threshold (TT), and to further the current knowledge of the neurophysiologic effects of TENS. STUDY DESIGN: Fifty healthy human subjects were randomly allocated in equal numbers to a control group or one of four TENS groups to receive electrical stimulation consisting of four combinations of TENS pulse durations (50microsec and 200microsec) and frequencies (4Hz and 110Hz). In the TENS groups, TENS was applied under double-blind conditions for 15 minutes over the superficial radial nerve in the dominant forearm. Over a 1-hour period, compound action potentials, MPT readings, and TT readings were recorded bilaterally. RESULTS: Only one combination of TENS parameters (110Hz, 200microsec) effected consistent changes in all of the variables assessed, ie, TENS produced a significant increase in negative peak latency while simultaneously increasing both MPT and TT. CONCLUSION: The findings from this study suggest that at least part of TENS-mediated hypoalgesia is a consequence of a direct peripheral effect of TENS, although a "central" effect may not be excluded.

Adult↗
PubMed1993

The electrophysiological consequences of electrode impalement of peripheral nerves in the rat.

Peripheral nerve fascicles are deliberately impaled during microneurography experiments. We have assessed conduction block under these circumstances. First we recorded compound action potentials (CAP) in the sural nerve following stimulation of the sciatic nerve. The insertion of injection and microneurography electrodes between stimulation and recording sites produced a 20% decrease in the size of the CAP, which was maintained for the 10 min duration of impalement. After withdrawal, the conduction block partially resolved. In other experiments, single-unit action potentials were recorded from L4 and L5 dorsal roots following peripheral nerve stimulation. Microneurography electrodes inserted into the sciatic nerve produced conduction block in 50% of these axons. When axons were blocked, anodal stimulation through the tungsten electrode became more effective than cathodal stimulation. These results suggest that a temporary conduction block occurs in a significant number of myelinated fibers near the site of an inserted electrode.

Action Potentials↗
PubMed1994

Glandular peripheral nerve sheath tumours.

Glandular differentiation in peripheral nerve sheath neoplasms is a rare but well recognised phenomenon, believed to represent the least common of the various forms of heterologous differentiation which may occur in tumours of peripheral nerve. This group of tumours--the 'glandular peripheral nerve sheath neoplasms'--are the subject of this short review. The majority of glandular peripheral nerve sheath neoplasms arise in patients with von Recklinghausen's disease and follow a malignant course, but both benign and sporadic forms have now been described. Neither the presence nor the appearance of the glandular foci are believed to influence patient outcome. Predictions of likely biologic behaviour are best based upon an assessment of the nature of the accompanying spindle cell stroma. Glandular peripheral nerve sheath neoplasms must be distinguished from various tumours of soft tissue which may share similar histological features e.g. synovial sarcoma and the epitheloid nerve sheath tumours. Immunohistochemistry and ultrastructural examination may aid in this regard, and have also contributed to our understanding of the nature and origin of the glandular structures, though questions regarding their histogenic origins remain somewhat controversial.

Cell Differentiation↗
PubMed1986

Undulating course of nerve fibres and bands of Fontana in peripheral nerves of the rat.

The undulating course of nerve fibres and the optical effect of that course, i.e. the bands of Fontana, were studied in the peripheral nerves of the adult rat using light microscopy. The arrangement of collagen fibres in the endoneurium of these nerves was evaluated using transmission and scanning electron microscopy. No nerve fibres undulation was noted on the intracranial sections of the cranial nerves or on the spinal roots. In their endoneurium a few, irregularly arranged collagen fibrils were found. In contrast, the nerve fibres undulation and Fontana's bands were a constant feature in the peripheral course of the nerve trunks. They were discernible in vivo and on excised unfixed as well as fixed nerves. The nerve fibres follow a sine-curve course of variable frequency and amplitude. Exposed in vivo, the nerve fibres retained their wave-like course even after removal of the epineurium and perineurium. The endoneurium of these nerves contained numerous undulating longitudinally oriented bundles of collagen fibrils. These findings suggest that the undulating course of the nerve fibres in peripheral nerves is conditional upon the quantity and arrangement of their endoneurial collagen fibrils. When the nerve was stretched in the course of movement, the undulation became straightened out until it disappeared. Conversely, nerve shortening enhanced the undulation. Thus the wave-like alignment of the nerve fibres represents a physiological reserve length for nerve stretching.

Animals↗
PubMed2005

[Monitoring retrograde adenoviral transgene expression in spinal cord and anterograde labeling of the peripheral nerves].

OBJECTIVE: Targeted adenoviral gene delivery from peripheral nerves was used to integrally analyse the characterization and time course of LacZ gene (AdLacZ) retrograde transfer to spinal cord and transgene product anterograde labeling of peripheral nerve. METHODS: Recombinant replication-defective adenovirus containing AdLacZ was administrated to the cut proximal stumps of median and tibial nerves in Wistar rats. Then the transected nerve was repaired with 10-0 nylon sutures. At different time point post-infection the spinal cords of C5 to T1 attached with DRGs and brachial plexuses, or L2 to L6 attached with DRGs and lumbosacral plexuses were removed. The removed spinal cord and DRCs were cut into 50 microm serial coronal sections and processed for X-gal staining and immunohistochemical staining. The whole specimens of brachial or lumbosacral plexuses attaching with their peripheral nerves were processed for X-gal staining. The number of X-gal stained neurons was counted and the initial detected time of retrograde labeling, peak time and persisting period of gene expression in DRG sensory neurons, spinal cord motor neurons and peripheral nerves were studied. RESULTS: The gene transfer was specifically targeted to the particular segments of spinal cord and DRGs, and transgene expression was strictly unilaterally corresponding to the infected nerves. Within the same nerve models, the initial detected time of gene expression was earliest in DRG neurons, then in the motor neurons and latest in peripheral nerves. The persisting duration of beta-gal staining was shortest in motor neurons, then in sensory neurons and longest in peripheral nerves. The initial detected time of beta-gal staining in median nerve models was earlier in median nerve models compared with that in the tibial nerve models. Although the initial detected time and the beginning of peak duration of beta-gal staining were not same, the decreasing time of beta-gal staining in motor and sensory neurons of the two nerve models were started at about the same day 8 post-infection. The labeled neurons were more in tibial nerve models than that in median nerve models. Within the same models, the labeled sensory neurons of DRGs were more than labeled motor neurons of ventral horn. The beta-gal staining was tender in median nerves than that in tibial nerves. However the persisting time of beta-gal staining was longer in tibial nerve models. CONCLUSION: The strong gene expression in neurons and PNS renders this system particularly attractive for neuroanatomical tracing studies. Furthermore this gene delivery method allowing specific targeting of motor and sensory neurons without damaging the spinal cord might offer potentialities for the gene therapy of peripheral nerve injury.

Adenoviridae↗
PubMed2002

Nerve conduction studies in selected peripheral nerve disorders.

PURPOSE OF REVIEW: The physiological properties of nerve and muscle are influenced by pathological changes and the aim of this review is to discuss recent contributions of electrophysiological studies to the understanding and diagnosis of selected peripheral nerve disorders. The relationships between pathology and physiology emphasize the close interdependence between electrophysiological studies, clinical deficits and other laboratory information. Attention should be paid to the strengths and limitations of electrophysiological methods, considering their impact on diagnosis and treatment of patients. RECENT FINDINGS: Several studies have shown particular pathophysiological profiles associated with different antibody subtypes in autoimmune peripheral neuropathies and this association further supports the suggestion of pathological specificity in both acute and chronic neuropathy. The sensitivity and specificity of physiological profiles therefore become increasingly important since some of these neuropathies are accessible to treatment. On the other hand, the pathophysiological and clinical profiles may be heterogeneous in patients with some disorders. This could be related to a more indistinct division between different types of pathology with increased understanding of pathogenetic mechanisms. Moreover, new insights into disturbed axonal function have stimulated attempts to develop methods to explore normal and diseased human nerve function. SUMMARY: The exploration of axonal membrane and ion-channel function has become accessible using studies of excitability and are of potential value where conventional studies only provide nonspecific evidence of the number of fibers and the integrity of myelin. These studies will presumably become increasingly important in the years ahead considering the lack of understanding of the functional disturbances in axonal neuropathies.

Animals↗
PubMed1997

Immunocytochemical distribution of Ca(2+)-independent protein kinase C subtypes (delta, epsilon, and zeta) in regenerating axonal growth cones of rat peripheral nerve.

In the peripheral nerve, regenerating axonal sprouts usually emanate at nodes of Ranvier, and extend as growth cones along the inner surface of Schwann cells and/or through Schwann cell columns in the distal nerve segment. In order to elucidate the significance of Ca(2+)-independent protein kinase C in nerve regeneration, localizations of delta, epsilon and zeta subtypes were examined immunocytochemically in sprouts and growth cones of regenerating axons, as well as in normal intact nerves in the rat sciatic nerve. In normal nerves, intense immunoreactivities of delta, epsilon and zeta subtypes were present in axons of both myelinated and unmyelinated fibres. Subcellularly, the distribution of these subtypes in the axoplasm was patchy, and discontinuous in the axolemma and subaxolemmal peripheral zones of myelinated nerves. Some thin myelinated axons showed no immunoreactivity for epsilon subtype. Schwann cells of both myelinated and unmyelinated fibres had moderate immunoreactivities for each subtype. In areas of nerve regeneration, axonal sprouts at nodes of Ranvier, and growth cones extending along Schwann cell basal laminae, had intense immunoreactivities for delta, epsilon and zeta subtypes which are distributed diffusely throughout the axoplasm, and on the entire axolemma. In the sprouts, immunoreactivity for epsilon subtype was strong on the axolemma, but weak or almost absent in the axoplasm. These data, together with those of our previous study, indicate that Ca(2+)-independent protein kinase C subtypes (delta, epsilon and zeta) have basically the same distribution patterns as those of Ca(2+)-dependent subtypes in sprouts and growth cones of regenerating axons, as well as in normal intact axons; albeit epsilon subtype is somewhat different in distribution and intensity from delta and zeta subtypes. It is suggested that Ca(2+)-independent subtypes are involved in maintaining growth cone activities along with the Ca(2+)-dependent subtypes.

Amino Acid Sequence↗
PubMed1978

Transcutaneous electrical nerve stimulation in chronic pain after peripheral nerve injury.

Transcutaneous electrical stimulation was tested in 24 patients with chronic pain following a peripheral nerve injury in an extremity, in 10 patients with a good effect. All of these 10 patients displayed signs of increased sympathetic activity in addition to hyperalgesia. Sympathetic block gave complete freedeom from pain. In 14 patients with the same symptomatology but without an increased or with only very slightly increased sympathetic activity, no or an insignificant effect was obtained. Sympathetic block did not relieve the pain in this group. Transcutaneous electrical stimulation should be tried as an alternative to sympathectomy in causalgia major or minor.

Adult↗
PubMed2003

[Choice of anesthesia in microsurgical procedures on peripheral nerves].

Microsurgical procedures on peripheral nerve lesions have their own specifics. Those are: duration and extent of operation, and need to change body position during operation. General endotracheal anesthesia has been used for operations on brachial plexus lesions with neural transfer; on peripheral nerve lesions with sural nerve autotransplantations; on all extracranial lesions (facial n. and lesion hypoglossal n.); for lesions of plexus lumbalis and sciatic nerve. These operations are requesting turning of patient on the lateral or ventral position or they are performed on head and neck. Because operation and anesthesia last longer, general ET anesthesia is more suitable for neurosurgeons and anesthesiologist's interventions. Regional anesthesia, i.e. neural plexus block, is suitable for operations on upper extremity. Then we perform brachial plexus block with more approaches. There has been frequently in use axillary approach which is easier to perform, has minimum of complications and is suitable for procedures at cubital region, forearm and hand.

Anesthesia↗