摘要:

AbstractAlthough electromyography (EMG = nerve conduction and needle electromyographic examination) is among the most sensitive and reliable approaches to detect and even to characterize certain aspects of nerve disease, it is important for physicians to appreciate that EMG has limited value in (1) inferring symptoms and neuropathic deficit (particularly the overall deficit recorded by clinical neurologists), (2) inferring involvement of small‐diameter fibers, (3) inferring underlying biochemical or other pathophysiologic derangement, (4) inferring the presence and type and pathologic alterations in single fibers or Schwann cells, or (5) inferring interstitial pathologic abnormality. For 1 and 2, an adequate neurologic history and examination in needed. For 2, quantitative sensory (QSE) and quantitative autonomic (QAE) examination and histologic study of nerve often are especially helpful. For 3, clinical evaluation and a variety of laboratory examinations are needed. For 4 and 5, clinical evaluation and/or pathologic study of nerve may be neededElectromyography has deservedly gained considerable acceptance as a worthwhile evaluative procedure for the study of neuromuscular disease. For some purposes, however it is of limited value and other evaluative procedures are more informative. In this review, I trace the history of some of the reasons for the popularity of EMG and highlight some of its limitations. The purpose is not to diminish EMG or to elevate the procedure of nerve biopsy, rather to provide a conceptual framework for how these techniques and the clinical and other laboratory examinations can be used together in the assessment and follow‐up of neuropa

ISSN:0148-639X    

DOI:10.1002/mus.880130502

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

年代:1990

数据来源: WILEY

摘要:

AbstractElectron‐microscopic immunoperoxidase technique revealed plasmalemmal localization of dystrophin in microscopically normal human skeletal muscle fibers obtained from nine routine diagnostic muscle biopsies. There was no evidence of periodicity of the immunoreactive product nor was there any evidence of immunostaining in any organelle besides the plasma membrane. Dystrophin appears to be a cytoskeletal protein associated with the plasmalemma. Its function is presumed to be the maintenance of the mechanical stability of the surface membrane so that it can withstand the normal contraction‐induced stresses without disrupt

ISSN:0148-639X    

DOI:10.1002/mus.880130503

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

年代:1990

数据来源: WILEY

摘要:

AbstractA case of spontaneous acute sensory neuronopathy is described in a previously healthy 19‐year‐old male. He had marked sensory ataxia with relative sparing of cutaneous sensation. There was no recovery over 4 years. Sural nerve biopsy showed modest axonal loss. Sensory evoked potentials were mildly abnormal in the face of absent sensory nerve action potentials. The long‐latency (R2) reflex was preserved whereas the short‐latency (R1) reflex was absent. The findings indicate that loss of large‐diameter (groupla) ganglion cells are primarily responsible for this

ISSN:0148-639X    

DOI:10.1002/mus.880130504

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

年代:1990

数据来源: WILEY

摘要:

AbstractSeveral groups of cases of fasciitis and myositis with eosinophilia are reported. The common features are inflammation into fascia and/or perimysium, and/or muscle fibers; eosinophilia in blood and/or in muscle biopsy. The following classification of 24 cases is suggested: at one end of the spectrum are fasciitis with eosinophilia: diffuse fasciitis (Shulman syndrome): 10 cases (3 with hematological complications); 2 cases of diffuse fasciitis with muscle atrophy; 3 cases of restricted fasciitis. Relapsing perimyositis with eosinophilia belong to the same spectrum, either diffuse (5 cases) with myalgias, or localized (2 cases). Other cases are focal myositis or multiple myositis, polymyositis with eosinophilia. The relationship among these cases is discussed. There is a continuum among the different groups. The pathophysiology remains unknown.

ISSN:0148-639X    

DOI:10.1002/mus.880130505

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe application of rapidly changing magnetic fields (magnetic stimulation) over the neck or lower back elicits EMG responses in the muscles of the arm or leg respectively. Such responses have stable onset latencies but their amplitudes vary depending on the position of the coil over the neck or lower back. Supramaximal responses could not be obtained. Comparison of onset latencies with estimates of peripheral conduction time using a conventional F‐wave technique suggest that the site of excitation of the motor axons is about 1.3 msec conduction time distal to the cervical motoneurons and 3 msec distal to the lumbosacral motoneurons. Response configuration after paravertebral magnetic stimulation was similar to that of the standard electrically evoked M‐wave in the small hand muscles but not in lower limb muscles. Responses in lower limb muscles after paravertebral magnetic stimulation may consist of additional F‐wave and H‐reflex components. The possible clinical role of paravertebral magnetic stimulation in the investigation of peripheral and central motor pathways is discussed in the light of these f

ISSN:0148-639X    

DOI:10.1002/mus.880130506

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

年代:1990

数据来源: WILEY

摘要:

AbstractA particular myasthenia gravis (MG) plasma Ig has previously been shown to block a single α‐bungarotoxin (α‐BuTX) binding site on embryonic rat muscle acetylcholine receptor (AChR). We have investigated its effect on embryonic/denervated and adult human AChR both in extracts and in situ. Plasma Ig blocked125I‐α‐BuTx binding by greater than 85% to the AChR extracted from denervated muscle, but only by 55% to AChR extracted from normal human muscle. Incubation of intact human muscle fibers with the plasma Ig reduced125I‐α‐BuTx binding to the endplate AChRs by 63%, and substantially decreased the amplitude of miniature endplate potentials. We conclude that anti‐α‐BuTx site antibodies, when present, can be important in the pathophysi

ISSN:0148-639X    

DOI:10.1002/mus.880130507

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe utility of the magnetic coil for stimulation of the cervical spinal nerves was compared to electrical stimulation by a monopolar needle cathode placed onto the spinal lamina in six volunteers. No statistical difference in average amplitudes or areas of evoked CMAPs was found although the size of the magnetic coil evoked potentials was less at C7–8 in several subjects. Electrical stimulation resulted in depolarization at a more proximal site. Electrical stimulation was associated with more discomfort, especially at C5–6. We conclude that electrical stimulation using a monopolar needle as the cathode is the superior technique for the clinical electrophysiologic study of the proximal brachial plexus and cervical spinal ner

ISSN:0148-639X    

DOI:10.1002/mus.880130508

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe cross‐sectional area of the fibers of hindlimb muscles of rats increased 10–40 times during the first 6 weeks after birth. Denervation at birth stopped the growth of the muscle fibers. The number of satellite cells decreased, and eventually all fibers vanished. Reinnervation, if any, was poor. Partial denervation did not induce collateral reinnervation. Some denervated gastrocnemius muscles were reinnervated and after 8–12 months contained hypertrophic fibers and signs of necrosis and regeneration. When soleus muscles were completely denervated and cross‐reinnervated after 4 weeks by the peroneal nerve, only half as many fibers became reinnervated after neonatal denervation as compared to muscles denervated at the age of 4 weeks. The experiments suggest that immature muscle fibers are less apt to become reinnervated than mature fibers. The few reinnervated fibers may be overloaded and therefore hypertrophy and eventually necrotize. Regeneration is abortive because satellite cells are scarce. These results may be relevant for the understanding of neuromuscular disorders with early (fetal

ISSN:0148-639X    

DOI:10.1002/mus.880130509

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

年代:1990

数据来源: WILEY

摘要:

AbstractElectrophysiologic findings in thallium intoxication are usually untimely, limited in extent, and often uninformative. This report documents serial conduction and electromyographic findings in a case of thallium poisoning, beginning 10 days after symptom onset and ending 24 months later. Initially, the plantar nerves in the foot demonstrated profound axonal loss while the sural and peroneal nerves were essentially normal. The latter two nerves subsequently underwent axonal loss. Two years were required for the sural and peroneal nerves to display recovery. At 24 months, the plantar nerves continue to remain absent. A primarily distal axonopathy, significantly worse in the lower than upper extremities and requiring more than 2 years for recovery, now documents what was previously speculated: the electrophysiologic course of thallium intoxication. Additionally, this case emphasizes the need to examine the plantar nerves of the foot to avoid missing distal axonopathies during the early course of the disease process. The clinical course and pathophysiology of thallium poisoning are also reviewed.

ISSN:0148-639X    

DOI:10.1002/mus.880130510

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

年代:1990

数据来源: WILEY

摘要:

AbstractMetabolic events were followed by 31‐P NMR spectroscopy during mechanical exhaustion of directly stimulated rat gastrocnemius. During mechanical fatigue, phosphocreatine (PCr) and pH first declined but although stimulation continued high values were recovered without mechanical recovery. Total recovery was only observed after cessation of stimulation. Partial mechanical recovery was elicited by lowering stimulation rhythm; it was accompanied by decrease in PCr to a steady–state level without pH alteration. When exhaustive exercise was induced immediately after nonexhaustive exercise, failure of mechanical function occurred without decrease in pH. Major findings were: first, during exhaustive stimulations, the greater the muscle fatigue, and the higher the PCr level at the end of stimulation. Secondly, PCr and force levels did not depend on preceding levels of PCr and pH. Thirdly, acidosis was observed transiently during the first minutes of the first exercise period. These findings strongly suggested that electrical events and/or excitation–contraction (EC) coupling play a crucial role in this type of fa

ISSN:0148-639X    

DOI:10.1002/mus.880130511

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

年代:1990

数据来源: WILEY