摘要:

AbstractThe acquired demyelinating polyneuropathies include acute (AIDP, Guillain‐Barré syndrome, GBS) and chronic (CIDP, dysproteinemic) forms which differ primarily in their temporal profile. They are inflammatory‐demyelinating diseases of the peripheral nervous system and likely have an immunologic pathogenesis. Although these neuropathies usually have a characteristic presentation, the electromyographer plays a central role in their recognition, since the demyelinating component of the neuropathy, which greatly reduces the differential diagnosis, is often first identified in the electromyography laboratory. In AIDP, the electromyographer, in addition to establishing the diagnosis, can sometimes predict the prognosis. Recognition of the chronic and dysproteinemic forms of acquired demyelinating polyneuropathy is important since they are treatable. The dysproteinemic forms also may be associated with occult systemic disorders that also may require treatment, independent of the neurop

ISSN:0148-639X    

DOI:10.1002/mus.880120602

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

年代:1989

数据来源: WILEY

摘要:

AbstractNerve and muscle blopsies were performed on 20 patients with HIV infection and peripheral neuropathy. Nine patients had distal symmetrical peripheral neuropathy (DSPN) (six ARC and three AIDS), six had inflammatory demyelinating polyneuropathy (IDP) (three ARC, one AIDS, and two otherwise asymptomatic patients), one had mononeuropathy multiplex (MM) (AIDS), 1 had mononeuropathy (ARC), one had meningoradiculitis (AIDS), and two had areflexia‐associated lymphocytic meningitides (ARC). DSPN exhibited axonal degeneration in four of nine cases and was associated with segmental demyelination in five of nine cases. IDP exhibited segmental demyelination associated with axonal degeneration in four of six cases. Demyelination was more frequent in asymptomatic patients (2 of 2 cases) and in ARC (7 of 12 cases), whereas axonal degeneration was predominant in AIDS (6 of 6 cases). Mononuclear cell infiltration was seen in 1 of 2 asympatomatic patients and in 11 of 12 ARC patients but was exceptionally found in AIDS (1 of 6 cases). Involvement of the walls of small vessels, mostly venules (“subacute microvasculitis”), was found in 1 of 2 asymptomatic patients, in 8 of 12 ARC patients, and never in AIDS. The polyclonal mononuclear cell population was composed mainly of Leu 2 (TB) positive cells in seven cases of ARC. No virions were seen in electron microscopy. HIV was isolated in two cases from the CSF or the nerve b

ISSN:0148-639X    

DOI:10.1002/mus.880120603

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

年代:1989

数据来源: WILEY

摘要:

AbstractAccessory hand muscles consistent with extensor digitorum brevis manus muscles were noted in a young women. Well‐defined compound muscle action potentials were elicited in these muscles with stimulation of the radial nerve. Needle electromyography showed poor recruitment and large motor unit potentials with frequent cramp discharges only in the anomalous muscles. Therefore, the extensor digitorum brevis manus is innervated by the posterior interosseous nerve, and symptoms may be due to chronic denervation and crampin

ISSN:0148-639X    

DOI:10.1002/mus.880120604

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

年代:1989

数据来源: WILEY

摘要:

AbstractAmong 13 patients with the Lambert–Eaton myathenic syndrome (LEMS), three different patterns on the repetitive nerve stimulation test were observed at the time of initial testing. Type 1 pattern, seen in one patient, had low normal CMAP amplitude, decremental response at the low rate of stimulation (LRS), and relatively normal response at the high rate of stimulation (HRS). Type 2, seen in nine patients, had the classical triad: low CMAP amplitude, decremental response at LRS, and incremental response at HRS. Type 3, seen in three patients, showed low CMAP amplitude, decremental response at LRS, and initial decremental response at HRS. We believe that these three patterns represent different degrees of blocking in LEMS, from the mildest in type 1 to the most severe in type 3. Since types 1 and 3 can be misinterpreted as myasthenia gravis patterns, they must be recognized in LEMS and an incremental response documented by prolonged stimulation at HR

ISSN:0148-639X    

DOI:10.1002/mus.880120605

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

年代:1989

数据来源: WILEY

摘要:

AbstractMyotonia is characterized by prolonged contraction (delay in onset of relaxation) of skeletal muscle fibers with characteristic electromyographic findings. Calcium channel blocking drugs may be expected to reduce myotonia, should they promote the onset of relaxation in a contracted skeletal muscle. This study was aimed at evaluating the effect of diltiazem, a calcium channel blocking agent, on myotonia induced by 2,4‐dichlorophenoxyacetic acid (2,4‐D).In rat diaphragm, exposed to 2.5 mM2,4‐D in a tissue bath, myotonia was quantified by documenting the contraction time in response to direct stimulation with supramaximal electric stimuli. At the peak of myotonia, different concentrations of diltiazem were added to the tissue bath and the effect on evoked contraction studied over a period of 6 minutes. A concentration of 5 × 10−5Mwas found to be the most effective, causing a decrease in contraction time of more than 90% in 3 minutes in 100% of specimens (n= 7).The above findings raise the possibility of using diltiazem as an antimyoton

ISSN:0148-639X    

DOI:10.1002/mus.880120606

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

年代:1989

数据来源: WILEY

摘要:

AbstractTo determine whether the decrease in muscle artifact provided by diazepam is of sufficient clinical value to justify its use, somatosensory evoked potentials recorded in examinations of 73 consecutive patients were compared with those recorded from 33 subsequent patients who were given 10 mg of diazepam orally just before the examination. With diazepam pretreatment there was clear improvement in the quality of lumbar and neck recordings—increased reproducibility and definition and ease of measurement— and also greater tolerance of the procedure and a slight shortening of time required for the t

ISSN:0148-639X    

DOI:10.1002/mus.880120607

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

年代:1989

数据来源: WILEY

摘要:

AbstractFibrous collagen from normal (line 412) and dystrophic (line 413) chicken pectoral muscles was examined for susceptibility to bacterial collagenase by a pH‐stat titration method to assess the kinetics of peptide bond hydrolysis. These experiments showed that there was a profound difference in the kinetics of hydrolysis using fibrous collagen purified from normal and dystrophic muscle. Although normal collagen was readily hydrolyzed by the collagenase, dystrophic collagen was not hydrolyzed in the presence of 200 μMCa and was hydrolyzed slowly in the presence of 5 mMCa. At this high Ca concentration, theKmfor collagenase was six times higher in dystrophic collagen than in normal, whereas the maximum reaction rate (Vmax) remained the same. After CNBr digestion, peptides from both sources were readily hydrolyzed by collagenase in the presence of 200 μMCa, and there was no noticeble difference in the reaction kinetics. The above results were not modified whether the chicken was sacrificed on day 4 or day 98 posthatching, and the insusceptibility to collagenase preceded the clinical manifestations of dystrophy. The structure of both fibrous and CNBr‐treated collagen from normal and dystrophic muscle was compared. One and two‐dimensional gel electrophoreses showed identical peptide maps. Gel filtration of CNBr peptides showed in the excluded volume the presence of twice as much high‐molecular‐weight (presumably crosslinked) peptides from dystrophic collagen compared with normal. We conclude that the intermolecular crosslinks are more extensively formed in dystrophic collagen and that this increased crosslinking results in the increased resistance of the dystrphic collagen to

ISSN:0148-639X    

DOI:10.1002/mus.880120608

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe resting tension and stiffness in the range of sarcomere lengths 2.4–3.6 μm were studied in highly inbred normal and dystrophic chicken pectoral muscle bundles, and the results were compared with the collagen content and the extent of crosslinkage of the collagen. All parameters increased in the order normal homozygote (003/003)

ISSN:0148-639X    

DOI:10.1002/mus.880120609

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

年代:1989

数据来源: WILEY

摘要:

AbstractAverage muscle fiber conduction velocity, mean power frequency, and mean EMG voltage have been measured in human vastus lateralis during prolonged isometric knee extensions at 10, 20, 30, and 40% of the maximum knee extension force. During contractions at 10 and 20% of maximum force, conduction velocity and mean power frequency rose as the contraction progressed, whereas the conduction velocity and mean power frequency fell at 30 and 40% of the maximum force. The mean EMG voltage rose during the contractions, with steeper increases for higher forces. It is argued that two principal factors influence the EMG during prolonged submaximal contractions: firstly, the fatigue of current active motor units, and, secondly, recruitment of fresh motor units. These factors act in opposition to muscle fiber conduction velocity. Recruitment gives an increase in average conduction velocity, whereas fatigue provokes a slowing in conduction velocity.

ISSN:0148-639X    

DOI:10.1002/mus.880120610

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

年代:1989

数据来源: WILEY

摘要:

AbstractSensory and autonomic small nerve fiber function was studied in 142 type I diabetics and 45 control subjects. Thermal sensitivity (TS), hot pain sensitivity, and the activity of sweat glands (SGs) were quantitated on the dorsum of the hand and the foot. TS was abnormal in 86% of patients in the foot and 66% in the hand. TS was more sensitive than the hot pain threshold, the number of pilocarpine activated SGs, or the amount of sweat secreted, all of which were abnormal in about 50% of patients for the foot and less than 25% in the hand. Thermal and sweating tests correlated significantly with the scores of abnormal temperature and pinprick sensation obtained by physical examination but not with the duration of the diabetes. TS was also correlated with motor and sensory nerve conduction parameters, but SG number was not. The results indicate that diabetic neuropathy has a variable presentation in different types of nerve fibers.

ISSN:0148-639X    

DOI:10.1002/mus.880120611

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

年代:1989

数据来源: WILEY