摘要:

AbstractThis study investigates the relationship between manual muscle test scores (MMT) and quantitative isometric strength measurements (QIS). It also evaluates the implications of that relationship for design of therapeutic trials. Extension and flexion strength at the elbows, hips, and knees of 21 neuromuscular disease patients were tested a total of 26 times utilizing both MMT and QIS testing. Paired data were evaluated with Spearman ranked correlation coefficients, and then QIS was predicted from MMT using Lowess, a consistent form of nonparametric regression. Finally, the implications of the Lowess analysis for designing a therapeutic trial were evaluated.MMT and QIS measurements were significantly correlated in all movements tested. Lowess analysis yielded prediction errors ranging from 16 to 24% of QIS range. Analysis of the sample size needed for a therapeutic trial suggested that a protocol measuring MMT would require more subjects for the same level of statistical significance as a protocol measuring QIS. Since it was not possible to reliably predict QIS values from MMT scores, such conversions are not appropriate for clinical use. This inconsistent relationship between MMT and QIS carries major implications for the design of therapeutic trials. Since therapeutic trials are time consuming, expensive, and most centers do not have large numbers of individuals available, using QIS as an outcome measure is a preferable research design.

ISSN:0148-639X    

DOI:10.1002/mus.880120302

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

年代:1989

数据来源: WILEY

摘要:

AbstractWe studied the electrical properties of intact muscle fibers from normal and malignant hyperthemia‐susceptible (MHS) pigs. Resting membrane potentials, action potentials, and current‐voltage relationships were measured with without the presence of halothane. There were no changes in the resting potentials or the specific membrane conductances at any concentration of halothane in either the normal or MHS fibers. The current‐voltage relationships of normal and MHS fibers did not differ. Contractures were observed in MHS muscle when the concentration of halothane was ≥0.8%. These halothane‐induced contractures were not associated with depolarization of the surface membrane. Contractures were not observed in normal muscle even at concentrations of 6.0% halothane. In contrast, halothane altered the shape of the action potentials of both MHS and normal fibers. However these changes were significantly greater in MHS fibers, occurred at much lower concentrations, and were partially prevented by preincubation in 10 μM

ISSN:0148-639X    

DOI:10.1002/mus.880120303

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

年代:1989

数据来源: WILEY

摘要:

AbstractTo evaluate the reliability of the in vitro contracture test for susceptibility to malignant hyperthermia, we studied muscles from normal pigs and those susceptible to malignant hyperthermia. We performed the contracture test with various muscles from the same animal. Trapezius and intercostal muscles gave similar results, whereas the extensor digiti II muscle had lower sensitivities to both caffeine and halothane. Thus, the muscle chosen to determine susceptibility to malignant hyperthermia is important. In several animals, a false negative diagnosis would have resulted if only the distal muscle had been studied, and this was true even if weak contractures (<200 mg) were considered significant. In addition, we compared the response to caffeine or halothane of cut and intact muscle fibers. Although the cut fibers were depolarized, the sensitivity to these drugs was unchanged. Hence, results of the in vitro contracture test are independent of the resting membrane potential.

ISSN:0148-639X    

DOI:10.1002/mus.880120304

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

年代:1989

数据来源: WILEY

摘要:

AbstractInternalized capillaries limited to type 1 muscle fibers were noted in seven patients. They occurred in each case in association with a similar admixture of neurogenic and myopathic features that included atrophic and hypertrophic fibers, internal nuclei, fiber splitting, and endomyseal and perimyseal fibrosis. Internalized capillaries in enlarged type 1 fibers arose from fiber splits on step section study of four patients. They occurred in the gastrocnemius, quadriceps, and soleus muscles from patients with a variety of disorders that included Becker dystrophy, diabetes mellitus and strenuous leg activities, Achilles tendon rupture, and myotonic dystrophy. Exercise‐induced myalgias were noted in the four patients with most plentiful intramuscular capillaries, and in three of these muscle hypertrophy was present. The concurrence of internalized myofiber capillaries and exercise induced myalgias may represent an associated biochemical/pathological defec

ISSN:0148-639X    

DOI:10.1002/mus.880120305

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

年代:1989

数据来源: WILEY

摘要:

AbstractNormal motor units (MUs) were simulated and their architecture altered to simulate the changes produced by myopathy. The concentric needle electromyographic recordings of motor unit action potentials (MUAPs) from the MUs were then also simulated. These simulated MUAPs showed features that are seen in myopathy: normal amplitude and slightly reduced area, MUAPs with simple waveform and reduced duration, and complex MUAPs with normal or increased duration. The MUAP waveforms were complex because of increased variability of fiber diameter and not because of loss of muscle fibers. The MUAP duration increased when the variability of fiber diameter increased. Finally, MUAPs similar to those seen in neurogenic diseases were produced from MUs in which the only abnormality was increased variability of fiber diameter.

ISSN:0148-639X    

DOI:10.1002/mus.880120306

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

年代:1989

数据来源: WILEY

摘要:

AbstractA 6‐year‐old boy was examined with the dual purpose of establishing whether he had malignant hyperthermia (MH) and to investigate his complaint of excessive muscle fatiguability. In the course of such investigations, McArdle's disease was diagnosed, and the patient was also identified as an MH‐positive re

ISSN:0148-639X    

DOI:10.1002/mus.880120307

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

年代:1989

数据来源: WILEY

摘要:

AbstractSince the popularization of routine creatine kinase (CK) measurement, an increasing number of patients with unexplained CK elevation (“asymptomatic hyper‐CK‐emia”) are being identified. We studied 19 patients with persistent CK elevation of unknown etiology with electromyography (EMG) and muscle biopsy. Needle EMG was abnormal in 14 patients. Muscle biopsy was positive in all individuals with abnormal EMG and in one patient with normal EMG. Diagnoses included polymyositis in five patients, morphologically nonspecific myopathy in three, mitochondrial myopathy in two, and sarcoid myopathy, central core disease, multicore disease, inclusion body myopathy, and McArdle's disease in one case, respectively. Five patients with abnormal biopsies developed weakness within 1 year of presentation. We conclude that persistent asymptomatic CK elevation represents mild or early myopathy in a majority o

ISSN:0148-639X    

DOI:10.1002/mus.880120308

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe system causing myofilament damage is separate from the phospholipase A2pathway, Ca activation of which ultimately causes sarcolemma breakdown in muscle cells. Mitochondrial agents cause myofilament damage in saponin‐skinned frog pectoris cutaneous muscle when [Ca] = 0. There are parallels with other systems that generate oxygen radicals. However, a variety of protectors against oxygen radicals, or anoxia, failed to protect; Ca‐activated damage was not augmented by diethylthicarbamate, nor was it accompanied by a respiratory burst. Thus, there is no firm evidence implicating oxygen radicals in myofilament damage. Thiol‐oxidizing agents cause contraction damage in skinned muscle that resembles the quasirigor induced in myosin byN‐ethylmaleimide. Activation of transmembrane dehydrogenases and electron flow produced damage and increased Ca sensitivity in skinned muscle, and it is suggested that this enzyme system may be implicated in characteristic damage to the myofilaments via redox cycling and modification of sulphydryl groups; its possible location on the sarcoplasmic reticulum is di

ISSN:0148-639X    

DOI:10.1002/mus.880120309

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

年代:1989

数据来源: WILEY

摘要:

AbstractPeripheral nerve injury due to handcuff placement has been reported in the past, always involving the superficial radial nerve, and sometimes involving other peripheral nerves at the wrist. We present two unusual cases in which the ulnar nerves were affected, but the radial nerves were normal or only minimally affected. This serves to emphasize a broader clinical spectrum of handcuff injury. Significant disability may result. These cases also involve alcohol intoxication, which may predispose patients to this type of injury because of overly aggressive application of restraints motivated by the patients' bellicose behavior.

ISSN:0148-639X    

DOI:10.1002/mus.880120310

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

年代:1989

数据来源: WILEY

摘要:

AbstractScanning electron microscopic (SEM) studies on intrafusal muscle fibers and their various sensory and motor endings are not available thus far although SEM greatly increases the resolution power for analyzing surface structures in comparison to light microscopic preparations. From a total of 68 isolated muscle spindles in lumbrical muscles of Wistar rats, only one primary sensory ending could be isolated. Secondary sensory endings were of an annulospiral, a flat, cuff‐shaped, or a more complicated branched type; they were always completely surrounding intrafusal muscle fibers. Motor terminals were more focally arranged not surrounding the muscle fibers. Three types could be distinguished. Collagen fibrils were seen to insect on capsular elements as well as on the surface of intrafusal muscle fibers. Thus SEM helps understanding the most complicated electromechanical system for motor contro

ISSN:0148-639X    

DOI:10.1002/mus.880120311

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

年代:1989

数据来源: WILEY