摘要:

AbstractIn the last few years, several conditions giving rise to increases of the MB and BB isoenzymes of creatine kinase, and several electrophoretic variants of creatine kinase, and several electrophoretic variants of creatine kinase have been described. This review summarizes the nonmyocardial causes of increases of both CK‐MB and CK‐BB and also discusses the various electrophoretic varia

ISSN:0148-639X    

DOI:10.1002/mus.880060203

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

年代:1983

数据来源: WILEY

摘要:

AbstractA prospective study of 114 patients with DMD provided data for “power” calculations for future therapeutic trials. There was a decline in strength of 0.4 units per year (on a 0‐10 scale). Contractures of the iliotibial bands, hip flexors, and heel cords developed before 6 years. Contractures of other joints accompanied the increased use of wheelchairs. All children walked until 8 years with functional “improvement” between 3–6 years. Children of the same age varied widely in their strength, degree of contracture, and functional abilities. Fifteen percent of the patients appear to have a milder variety of the disease and are termed “outliers.” To test a drug which might slow the disease to 25% of its original rate of progression, two groups (placebo and treatment) of 40 patients each would have to be follow

ISSN:0148-639X    

DOI:10.1002/mus.880060204

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe number of newly formed myelinated nerve fibers was counted in the sciatic and tibial nerves in the rat following sciatic nerve crush. Beginning at days 8 and 14 in the sciatic and tibial nerve, respectively, the number of new myelinated fibers increased steadily and eventually exceeded the original number by 40 and 30%, respectively. This overshoot in nerve fibers was accompanied by the presence of clusters of fibers. Both the overshoot and the clusters disappeared at later stages and returned gradually to normal values within 3 months. Chronic administration of ACTH4‐10to the animals resulted in higher numbers of new myelinated nerve fibers throughout the process of regeneration. This stimulation was most pronounced (a three‐fold increase) during the initial stages of regeneration. A higher number of myelinated nerve fibers was also observed in ACTH‐treated rats 60 and 96 days after sciatic nerve crush. No changes in diameter of the fibers could be observed. The results are discussed in terms of a stimulation of the number of outgrowing nerve fibers caused by the peptide trea

ISSN:0148-639X    

DOI:10.1002/mus.880060205

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

年代:1983

数据来源: WILEY

摘要:

AbstractMembrane potentials, current–voltage relationships, and contractile parameters were studied in intact muscle cell bundles obtained from two patients with adynamia episodica hereditaria. In a normal extracellular medium, the cell membranes had resting potentials of about –80 mV and their current–voltage relationships were not significantly different from control curves. In contrast to normal muscles the afflicted cells were paralyzed in a medium having 6–10 mmol/liter potassium. The mechanisms of paralysis in the two specimens were different from each other. Many fibers from one patient were spontaneously active even in normal solution. In high potassium solution spontaneous activity was increased and the cells gradually depolarized to values at which excitatory sodium current is normally inactivated. This depolarization was connected with an increased sodium conductance and was reversed by the application of tetrodotoxin (TTX). The fibers from the other patient were not spontaneously active. In high potassium solution they were paralyzed at membrane potential values at which normal fibers would still contract. The reason for this paralysis was a reduced excit

ISSN:0148-639X    

DOI:10.1002/mus.880060206

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

年代:1983

数据来源: WILEY

摘要:

AbstractEffects of sera or immunoglobulins from patients with acquired myasthenia gravis on motor neuron survival during critical stages of embryonic development were investigated in the trochlear nucleus–superior oblique muscle system of white Peking duck embryos. A significant increase in motor neuron survival occurred following application of myasthenia gravis sera or myasthenic immunoglobulin during the period of embryonic death of motor neurons. There was no reduction in limb or extraocular muscle movement in treated embryos. Trochlear motor neuron survival persisted after sera or immunoglobulin treatment was discontinued. The total number of muscle fibers and acetylcholine receptros were unchanged following immunoglobulin treatment. Myasthenic immunoglobulin is therefore unique in preventing motor neuron death without producing muscle paralysis and in promoting a prolonged augmentation of motor neuron survival. It is concluded that factors other than muscle activity may also control neuron survival during embryogenesis. Previous studies of myasthenic sera in muscle have shown effects only postsynaptically. This is the first demonstration that myasthenic immunoglobulin affects structures in the central nervous syste

ISSN:0148-639X    

DOI:10.1002/mus.880060207

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

年代:1983

数据来源: WILEY

摘要:

AbstractClinical and experimental data indicate that long‐term corticosteroid use leads to atrophy of the type 2 muscle fibers. The purpose of this study was to characterize and quantify the nature of muscle function in rheumatic disease patients who have been on long‐term corticosteroid therapy. Quadriceps function (i.e., peak torque and power) in 19 patients (11 with rheumatoid arthritis, five with systemic lupus erythematosis, and 3 other) and 11 age‐ and activity‐matched normal controls was measured with an isokinetic dynamometer (Cybex II), during four constant velocity movements. Power was significantly lower for the patients at all speeds. At the higher speeds the patients' deficit in power production increased as indicated by a difference in the slopes of power‐velocity regression lines. Measures of peak torque could not be consistently used to differentiate the groups. Patients with rheumatic diseases receiving corticosteroids have a decreased ability to generate muscle power. The method described allows for quantification of these deficits in a clinica

ISSN:0148-639X    

DOI:10.1002/mus.880060208

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

年代:1983

数据来源: WILEY

摘要:

AbstractAging of skeletal muscle in the hindleg of the mouse is accompanied by a progressive increase in the amount of the interstitial tissue and especially that of lipid cells and fibroblasts. Quantitative analysis indicates that there was a nonsignificant increase in the total number of muscle fibers per unit area, perhaps due to a splitting process. The proportion of high oxidative fibers was decreased to a nonsignificant degree, and the remaining high oxidative fibers underwent a significant compensatory hypertrophy. Concomitantly, the number of low oxidative fibers increased significantly. This study revealed that endurance training in young animals induced morphometric changes very similar to those noticed in intact aging animals (i.e., splitting phenomenon, hypertrophy of high oxidative fibers, and an increased proportion of low oxidative fibers). It also became apparent that the skeletal muscle of old animals lacks the capacity to respond to enforced training, except for a further increase in the proportion of low oxidative fibers. It appears that aging muscle is unable to adapt to changing environmental circumstances.

ISSN:0148-639X    

DOI:10.1002/mus.880060209

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

年代:1983

数据来源: WILEY

摘要:

AbstractTwo siblings and a first degree cousin of a consanguinous marriage were afflicted with recessive generalized myotonia (RGMy). All had muscle weakness which was particularly prominent after rest, thinning of the forearms, weakness of anterior compartment muscles, and muscular contractures. The first degree cousin was the most severely afflicted with congenital myotonia. Muscle biopsy and electromyography were consistent with a myopathy. Exercise after rest demonstrated a marked reduction in muscle membrane excitability in all patients.

ISSN:0148-639X    

DOI:10.1002/mus.880060210

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

年代:1983

数据来源: WILEY

摘要:

AbstractIsometric contraction time (Tc) of 19 fast and slow rat motor units in the soleus and the tibialis anterior muscles was measured. The motor unit fibers subsequently marked by glycogen depletion were histochemically fiber typed as well as analyzed ultrastructurally with respect to volume of the sarcoplasmic reticulum terminal cisternae. The volume density of terminal cisternae (VvTC) was inversely related to Tcover the whole range of motor units, irrespective of type of muscle. The continuous variations in VvTC are concluded to match the extrinsic control of time course of contraction, and fusion frequency of the motor unit to match the frequency characteristics of the individual motoneurons. The volume density dependence of terminal cisternae function would result in an indirect coupling between amount and rate of calcium release and rate of calcium recaptured. VvTC and Tcwere the same for some tibialis anterior and soleus motor units in spite of the different types of myosin, indicating that the type 1 and type 2 myosins have specific structural differences in fast as compared with slow muscles.

ISSN:0148-639X    

DOI:10.1002/mus.880060211

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe chronic administration of nafenopin, a hypolipidemic drug, induced an increase in catalase and acyl‐CoA oxidase activities in various skeletal muscles, including the gracilis, diaphragm, soles, and extensor digitorum longus. The magnitude of the increase was around 100% for both enzymes in each of the muscles studied in spite of the different basal level. These changes seem to be specific of the peroxisomal enzymes because acetylcholinesterase, which is not peroxisomal, did not follow the same pattern in all the muscles. Concomitant with the increase in muscle peroxisomal enzymes, the skeletal muscles presented an altered electromyogram with prolonged insertional activity, repetitive firing of action potentials, and myotonic runs characteristic of myotonia. Our results suggest a role for peroxisomes in the myotonic disorde

ISSN:0148-639X    

DOI:10.1002/mus.880060212

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

年代:1983

数据来源: WILEY