摘要:

AbstractAn adult male with C‐7 quadriplegia developed neck pain. Axillary F central latencies were prolonged, and MRI showed a syrinx extending to C‐1. After shunting, F latencies normalized. At subsequent follow‐up, a rostral syrinx persisted by magnetic resonance imaging (MRI); motor evoked potential (MEP) latencies were prolonged but F latencies were normal. Later, the syrinx was less distended by MRI, MEPs normalized, and strength improved. We discuss the electrophysiologic methods available for diagnosing and monitoring posttraumatic syringomyelia. © 1992 John Wiley&Son

ISSN:0148-639X    

DOI:10.1002/mus.880150702

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractHyperosmotic neurosecrtion was used to measure basal and insulin‐stimulated amino acid and myoinosital transport into rat motor nerve terminals. L‐Alanine and α(methylamino)‐isobutyric acid (a nonmetabolizable system A‐specific analog) transport was rapid into motor nerve terminals innervating a fast‐twitch muscle, the extensor digitorum longus, and slow into motor nerve terminals innervating the soleus, a slow‐twitch muscle. A physiological concentration of insulin, 10 μU/mL, increased L‐alanine and α(methylamino)‐isobutyric acid transport into motor nerve terminals in the soleus. Large doses of insulin, 100 or 1000 μU/mL, had no effect on L‐alanine or α(methylamino)‐isobutyric acid transport into nerve terminals in the extensor digitorum longus. There was negligible basal or insulin‐stimulated transport of D‐alanine or myoinsitol into nerve terminals of the soleus or extensor digitorum longus. These studies show that insulin regulates sterospecific amino acid transport into extensor digitorum longus motor axons. Differences in basal and insulin‐stimulated tranpsort suggest that motor axons differ in their metabolism, and might be selectively v

ISSN:0148-639X    

DOI:10.1002/mus.880150703

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractEleven acute radial nerve palsies were examined between 3 days and 14 weeks following the onset of the neuropathy. Our objective was to quantify the relative extent of axon loss and conduction block in radial motor fibers supplying the extensor and abductor pollicis longus (EPL/APL) muscles. In 10 of 11 cases, conduction block exceeded axon loss. Maximum motor and sensory conduction velocities were normal distal to the spiral groove, suggesting that the larger myelinated fibers were not selectively involved in this acute neuropathy. The localization of the conduction block and slowing was, in every case, across the spiral groove. This method provides a relatively simple way of assessing the approximate contributions of axon loss and conduction block, and fits well with the early and usually complete clinical recovery in these cases.

ISSN:0148-639X    

DOI:10.1002/mus.880150704

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractEpidermal growth factor (EGF) and bovine serum albumin (BSA) are both required for serum‐free clonal growth of human muscle satallite cells (HMSC). However, neither inhibits differentiation of HMSC, and when both are added to a minimal serum‐free differentiation medium, they enhance survival and maintenance of human myotubes. A combination of 10 ng/mL EGF and 0.5 mg/mL BSA, added to MCDB 120 plus 10 μg/mL insulin, increasesboth total protein per dish and total creatine kinase activity, and keeps the myotubes in good condition for a longer period of time. The myotubes become cross‐striated and exhibit frequent spontaneous twitching. Substantial amounts of neonatal myosin heavy chain and the MM isozyme of creatine kinase are expressed, together with detectable amounts of adult fast myosin heavy chain. With regular feeding, these cultures can be maintained for at least 3 weeks with no overgrowth by mononucleate cells, and with far less degeneration than with insulin as the only supp

ISSN:0148-639X    

DOI:10.1002/mus.880150705

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThis study investigated the relation of muscle fiber conduction velocity (MFCV) to difference power spectrum mean frequency (MF), their fatigue trends, and differences between their values and their fatigue trends in various neuromuscular disorders. Electromyographic interference pattern was recorded inside the biceps in continuous isometric maximal voluntary contractions. Each subject was encouraged to pull for as long as possible. Fatigue was calculated as percent of time to complete inability to sustain contraction. The MFCV was computed by cross‐correlation. The MF was computed by differencing, windowing, FFT, squaring of coefficient, and repeat averaging. There were 33 healthy, 86 polyneuropathic, 28 myasthenic, 13 myotonic, and 32 myopathic patients. Both MFCV and MF changed significantly with fatigue–the MFCV linearly, while the MF in a markedly nonlinear fashion. Both were found to be insensitive to the end stages of muscle fatigue–the MFCV did not change its slope toward complete fatigue, and the MF did not change at all beyond the 40% fatigue point. A statistically sound fatigue regression equation was derived for each, and a nonlinear equation was found to best describe their relationship. Neither MFCV nor its fatigue changes were found to be significantly different across the neuromuscular disorders. The MF, however, was found to be significantly different in some neuromuscular disorders in both its average values and fatigue trends. This study showed, in contrast to the literature, a nonlinear relationship between MFCV and MF. It also shows that neither the MFCV nor the MF had reasonable diagnostic power on its own; however, the MF was very promising to serve as an adjunct to other vari

ISSN:0148-639X    

DOI:10.1002/mus.880150706

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractAmiodarone was injected endoneurially at increasing doses into the exposed tibial nerve of rats to study its electrophysiologic and pathologic effects on peripheral nerve fibers. Forty‐five male Wistar rats were used, and each of the following concentrations was injected into 15 nerves: 25 μg/mL, 50 μg/mL, and 100 μg/mL. Microinjection of a 25 μg/mL concentration of amiodarone resulted in a subacute, incomplete conduction block evident at day 3 postinjection. This conduction block remained stable until day 10 and recovery was complete at day 35. Microinjection of a 50 μg/mL concentration of amiodarone produced a faster evolving conduction block, and significant axon degeneration (approximately 40% of fibers). Injection of a 100 μg/mL concentration resulted in severe acute motor axon degeneration followed by complete but delayed regeneration. Results of morphological studies closely correlated with electrophysiological findings. Amiodarone thus seems to have a direct toxic effect on axons at high concentrations in the peripheral nerve, and we suggest that different pathological changes described in human amiodarone neuropathy could be related to different concentrations of the drug in the nerve, perhaps due to variability of blood‐nerve barrier

ISSN:0148-639X    

DOI:10.1002/mus.880150707

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractEosinophilia–myalgia syndrome (EMS) is a newly recognized disorder, characterized by myalgia, weakness, scleroderma‐like changes, and eosinophilia. EMS is associated with lots of L‐tryptophan allegedly contaminated with byproducts of the manufacturing process. We describe 3 patients with EMS who presented with a severe demyelinating sensorimotor polyneuropathy. Electrodiagnostic studies revealed multifocal conduction block, slowing and temporal dispersion of motor responses, and prolonged or absent F‐responses. Despite plasmapheresis; corticosteroids; and, in 1 patient, cyclophosphamide, 2 patients died and the remaining patient experienced minimal recovery. Pathology revealed patchy perivascular infiltrates and fibrosis in the connective tissue of muscle and nerve. Autopsy of the central nervous system in 2 patients did not reveal changes unique to EMS. In addition to other organ involvement, EMS may manifest as a potentially fatal polyneuropathy, which initially appears to have prominent demyelinating f

ISSN:0148-639X    

DOI:10.1002/mus.880150708

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThere has been no reliable evidence that the actions of anabolic steroids extend to limb muscles. In this study, female rabbits were treated with anabolic steroid (nandrolone decanoate) or arachis oil placebo for 4 weeks or 12 weeks. After 12 weeks, tibialis anterior muscles of treated animals showed highly significant increases in wet weight (38%), twitch tension (66%), maximum isometric tetanic tension (48%), maximum cross‐sectional area (27%), and specific tension (17%). Fiber type composition showed a significant trend toward a less oxidative metabolic character. The experiments provided clear physiological and morphological evidence of a steroid‐induced hypertrophy that was not attributable to fluid retention or changes in body weight. Of the muscles examined, the myotrophic effect was confined to the tibialis anterior muscle; extensor digitorum longus, plantaris, and soleus muscles showed no significant response. The work establishes an experimental model for the response of limb muscles to anabolic compou

ISSN:0148-639X    

DOI:10.1002/mus.880150709

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractConduction along the sural nerve was studied in 64 normal subjects using near‐nerve electrodes. Conduction velocities over the same nerve segments were calculated: (1) from the latency recorded from a site of stimulation to a site of recording (1R‐method); and (2) from the difference in latency between 2 recording sites, the site of stimulation being situated elsewhere along the nerve (2R‐method). Consistently faster velocities were seen with the 2R‐method and could best be explained by a fixed delay of about 0.15 ms at the stimulus site (latency of activation, utilization time). This delay was markedly prolonged when a ramp rather than a rectangular stimulus was applied, though fast fibers were excited with both types of stimuli. The delay is thought to be dependent on the relationship between the density of current at the stimulus site and the threshold of responding fibers. © 1992 John Wiley&S

ISSN:0148-639X    

DOI:10.1002/mus.880150710

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractWe report the first case of McArdle's disease (muscle phosphorylase deficiency) and tophaceous gout. To examine the contribution of adenine nucleotide degradation to the disturbance of uric acid metabolism, we labeled the adenine nucleotide pool with [8‐14C]adenine, and measured plasma and urine purines following vigorous exercise tests. Plasma and urinary hypoxanthine and xanthine concentrations and the specific radioactivity of urinary purines increased markedly, but plasma urate levels and uric acid excretion were not substantially modified. We suggest that, in this patient, the association of McArcle's disease with gout is coincidental. © 1992 John Wiley&Sons, I

ISSN:0148-639X    

DOI:10.1002/mus.880150711

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY