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Results for “Peripheral Nerves”

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At least 19 recordsLinked to original sources
PubMed1976

Infection of armadillos with Mycobacterium leprae. Ultrastructural studies of peripheral nerve.

Peripheral nerves of armadillos were studied 16 to 30 months after intradermal or intravenous inoculation with Mycobacterium leprae. Numerous bacilli were found within macrophages, Schwann cells, and perineurial cells; endothelial cells, pericytes and fibroblasts were involved as well. The bacilli were characteristically contained in membrane-limited vacuoles that were interpreted as being phagosomes. Some of the phagosomes contained granular, membranous, and vesicular debris considered to be bacillary degradation products, suggesting that lysosomal activity was present within the phagosomes. Multivesicular bodies, a few of which contained bacilli, were abundant in macrophages and perineurial cells. An unusual proliferation of irregular tubulovesicular profiles was noted, especially in Schwann and perineurial cell cytoplasm, surrounding and within phagosomes containing bacilli. The pattern of cellular involvement of neural structures with M leprae was similar to that observed in lepromatous leprous neuritis in humans.

Animals↗
PubMed1977

Incorporation of glycoproteins into peripheral nerve myelin.

Peripheral nerve myelin contains a dominant low molecular weight glycoprotein called Po. To study the metabolism of this glycoprotein, tritiated fucose was injected into the peripheral nerves of adult mice and developing rats, and the temporal distribution of label was examined by autoradiography and gel electrophoresis. Mice and rat pups, injected with fucose, were sacrificed from 1 h to 98 days later. Series of autoradiographs were prepared. At the shortest labeling periods, newly formed product was confined to juxtanuclear Schwann cell cytoplasm, in association with regions rich in Golgi apparatus. After longer labeling periods, silver grain levels in Schwann cell cytoplasm decreased; concomitantly, there was an increase of silver grains associated with myelin. In adult animals, label associated with myelin was concentrated over outer layers of thickly myelinated fibers. Even at the longest time intervals examined (72 and 98 days), this distribution of label was largely retained. In contrast, in developing animals, label became associated with inner layers of the thicker sheaths. At no time was label observed over axons. Gel electrophoresis revealed that tritiated fucose was a suitable precursor for the faster migrating peripheral nerve glycoprotein(s). At all times examined, there was a single major peak of radioactivity that co-migrated on sodium dodecyl sulfate (SDS) acrylamide gels with the Po protein. Sometimes, a faster migrating shoulder of radioactivity was noted. With increased labeling periods, there was an enrichment of radioactivity associated with Po, indicative of a relatively slow turnover rate.

Animals↗
PubMed1978

Recent developments in peripheral nerve surgery. Management of open traumatic peripheral nerve lesions.

The modern technique of operative repair of traumatic nerve interruption is discussed. The results of microsurgical repair have proved to be superior to those of conventional methods. Besides the anatomy and the operative technique, the indications and timing for surgical intervention are discussed. Reference to the literature and the authors' own experience show that delayed primary repair is the method of choice.

Humans↗
PubMed1979

Subperineurial space of the sural nerve in various peripheral nerve diseases.

The size of the subperineurial space of the sural nerve has been evaluated quantitatively in 69 cases of various peripheral nerve diseases and in controls. A significant increase was found in beriberi neuropathy (6 cases) and idiopathic polyradiculoneuropathy (9 cases) as compared with the control (8 cases). On electron microscopy a few macrophages, fibroblast processes, collagen fibrils with a diameter of 50 nm, microfibrils with a diameter of 8 nm, and amorphous material were observed in both the enlarged subperineural space and the endoneurial intercellular space. They were less frequently observed in controls. No significant correlation was found between the size of subperineurial space and the density of myelinated fibers.

Adolescent↗
PubMed1977

Nerve grafting in the repair of complicated peripheral nerve trauma.

Peripheral nerve trauma has been a challenge to surgeons, with significant advances in the surgery of repair occurring in major wars. The standard method of treatment involving wide mobilization and end-to-end suture to close traumatic gaps in peripheral nerves has not produced consistently acceptable results, particularly with large gaps. However, with the recent development of microsurgical techniques and instrumentation, the method of interfascicular nerve grafting has been applied to selected patients with trauma problems of the peripheral nerve, by resecting and autogenous nerve grafting at staggered levels to distribute scar formation, followed by plaster immobilization for 3 weeks. Ten patients are reported, with motor nerve recovery ranging from M2 to M4 and sensory recovery, S2-S4 (See Table I), based on Seddon's classification (11).

Adolescent↗
PubMed1978

Effect of parathyroid hormone and uremia on peripheral nerve calcium and motor nerve conduction velocity.

Peripheral neuropathy is not an uncommon complication of chronic uremia. Because parathyroid hormone, by raising brain calcium, is partly responsible for central nervous system aberrations in uremia, we studied the relative role of uremia, per se, and(or) parathyroid hormone on peripheral nerve calcium and motor nerve conduction velocity (MNCV). Studies were made in six groups of six dogs each, as follows: (a) normal dogs, (b) thyroparathyroidectomized (T-PTX) animals, (c) dogs with 3 days of uremia produced by bilateral nephrectomy, (d) T-PTX before the induction of acute renal failure, (e) normal dogs receiving 100 U/day of parathyroid extract (PTE) for 3 days, and (f) normal animals receiving 3 days of PTE followed by 5 days without PTE. Calcium content in peripheral nerve (expressed as milligram per kilogram of dry weight) was 252+/-5 (SE) in normal animals and 262+/-4 in T-PTX dogs. It was significantly (P < 0.01) higher in dogs with acute renal failure and intact parathyroid glands (410+/-12) and in normal animals receiving PTE (362+/-7). T-PTX, before acute renal failure, prevented the rise in peripheral nerve calcium (262+/-4) and PTE withdrawal was followed by the return of peripheral nerve calcium to normal (261+/-3). The increments in peripheral nerve calcium were associated with slowing of MNCV. It decreased significantly from 70+/-4 to 43+/-1 m/s after 3 days of acute uremia in dogs with intact parathyroid glands and T-PTX before acute renal failure prevented the fall in MNCV. Administration of PTE to normal animals reduced MNCV from 63+/-3 to 35+/-3 m/s and the withdrawal of PTE restored MNCV to normal (73+/-2 m/s). The results show that (a) excess parathyroid hormone increases peripheral nerve calcium and slows MNCV, (b) T-PTX, previously performed, prevents these changes in acute uremia, and (c) the withdrawal of PTE administration is followed by a reversal of the abnormalities.

Animals↗
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↗
PubMed1978

A light microscopic study of bovine peripheral nerve sheath tumours.

Peripheral nerve sheath tumours from 66 cattle were classified as schwannomas and neurofibromas. Bovine neurofibromatous tissue probably represents a dysplasia whilst bovine schwannomas are true neoplastic growths. Bovine schwannomas probably develop from neurofibromatous nerve and the two entities may represent parts of a single pathological condition.

Animals↗
PubMed1977

The characterization of type I and type III collagens from human peripheral nerve.

The normal chemical features of peripheral nerve collagens were determined on postmortem, histologically normal adult human femoral nerve. 1. Genetically distinct type I, [alpha1(I)2]alpha2, and type III, [alpha1(III)]3, were isolated by differential salt precipitation and the component subunit chains, alphal(I), alpha2 and alphal(III) were obtained by ion-exchange chromatography and gel filtration. 2. The molecular weight of alphal(I) and alpha2 of type I collagen was 95 000 and that for type III was 280 000. Reduction of type III with dithiothreitol yielded expected alpha1(III) chains of 95 000 molecular weight. 3. The amino acid composition of the three collagen chains, alpha1(I), alpha2, and alpha1(III), was the same as previously reported values for the corresponding chains from human skin except for slightly elevated hydroxylysine content. 4. Peripheral nerve collagen was found to contain 81% type I collagen and 19% type III. These results indicate that peripheral nerve collagen characteristics closely simulate that of human skin and differ from that of human aorta and other parenchymal organs. These data will permit a chemical analysis for possible abnormalities of peripheral nerve collagen in various neurogenic disorders.

Aged↗
PubMed1978

Studies on myelin proteins in human peripheral nerve.

The myelin fraction from human peripheral nerve was prepared. Two basic protein fractions (BF-P2 and PB) were isolated from acid extracts of the myelin fraction and three glycoproteins (BR-PO, PASII and Y protein) were purified from its acid-insoluble residue. In biochemical analysis the human BF-P2 protein (M.W.13,000) showed similar but not identical properties to bovine BF-P2 protein. The PB fraction was suggested to include the encephalitogenic CNS-BP (M.W.18,000) and another, new protein of similar molecular weight. Both the human BR-PO protein (M.W.28,000) and PASII protein (M.W.13,000) showed similar biochemical properties to the corresponding myelin proteins of bovine peripheral nerve, while they both are clearly different from other myelin proteins. Close relationship between the BR-PO protein and the Y protein (M.W.22,000) was suggested by amino acid analysis. Injection of the myelin fraction of bovine peripheral nerve with the complete adjuvant produced EAN while the CNS-BP induced EAE in laboratory animals. However, all three purified proteins, BF-P2, BR-PO and PASII, from bovine peripheral nerve myelin were inactive in inducing demyelinating diseases.

Amino Acids↗
PubMed1979

Autotomy following peripheral nerve lesions: experimental anaesthesia dolorosa.

(1) When hindlimb peripheral nerves are cut across in rats and mice, there is a tendency for the animal to attack the anaesthetic limb. We have called this attack "autotomy". In this paper we describe the time course and degree of autotomy following various types of nerve injury. (2) Four different types of lesion were applied to the sciatic nerve of rats. The most serious autotomy was produced by section of the nerve and encapsulation of its cut end in a polythene tube. Section followed by immediate resuturing also produced serious autotomy. Simple ligation of the nerve end was followed by less autotomy than encapsulation or cut and resuture. A crush lesion caused only minimal attack. (3) Section of the saphenous branch of the femoral nerve produced no autotomy. However, if the saphenous and sciatic nerves were ligated at the same time so that the entire foot became anaesthetic there was a great increase of autotomy over that seen when the sciatic nerve alone was ligated. This increase with the double lesion occurred even if the saphenous nerve was ligated more than 100 days after the sciatic nerve had been cut. (4) Mice showed autotomy very similar to that seen in rats but the onset was somewhat faster. (5) Reasons are given to propose that autotomy is triggered by an abnormal afferent barrage generated in the cut end of the nerve. Autotomy from peripheral nerve lesions is a different phenomenon from that seen after dorsal root section. Autotomy occurs under conditions which produce anaesthesia dolorosa in man. This simple model may be suitable for studies of the prevention of irritations originating from chronic lesions of peripheral nerves.

Animals↗
PubMed1979

Differential atrophy of sensory and motor fibers following section of cat peripheral nerves.

Differential effects of peripheral nerve section on myelinated sensory and motor fiber populations were investigated in 5 hindlimb nerves of cats. Upon electrical stimulation of each nerve, monophasic compound action potentials were recorded from the L6, L7 and S1 dorsal and ventral roots, and the impedance of each root was measured. The decline in the electrical charge computed from potentials 43 to 252 days after nerve section gave a measure of the effect of axotomy on the diameters of sensory and of motor fibers in each nerve. No significant difference in the rate of atrophy of sensory and motor fibers was observed after about 45 days following nerve section. After about 145 and 245 days, however, dorsal root charge contributions had decreased significantly more than ventral root values. Exponential decay curves were fitted separately to charge data for sensory and for motor fibers. The calculated value for the endpoint of the decay was about 35% of the control value for motor fibers, and not significantly different from zero to sensory fibers. These results suggest that in response to axotomy, myelinated motor fiber diameters decline at first but later stabilize, while myelinated sensory fibers continue to decline and may atrophy completely if regeneration is prevented. Possible roles of electrical activity and of 'trophic' interactions with the periphery in the maintenance of cell properties are discussed.

Animals↗
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↗
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↗
PubMed1979

Tension and creep phenomena in peripheral nerve.

Tension introduced into peripheral nerves during their surgical repair may reduce the success of this procedure. Two mechanical factors are important; the tension required to effect a repair, and the rate at which this tension changes after surgery. These two factors have been investigated in the rat sciatic nerve. The results show an increasing resistance to elongation of the nerves with increasing tension. Under a constant elongation the tension in the nerves reduces by about 30 per cent in the first 10 minutes and by a small amount in the following 20 minutes.

Animals↗
PubMed1976

Nerve suture without tension, a method for repairing transected peripheral nerves.

An analysis of primary epineural end to end sutures of transsected peripheral nerves, operated upon before 1970, showed good motor and sensory function in only 60%. With the new perineural suturing technique without tension and if necessary by using autologous nerves for bridging large nerve defects the good results raised to 87%.

Humans↗