摘要:

AbstractAmyloid fibrils were isolated from the myocardium of two patients with familial amyloid polyneuropathy. The solubilized amyloid fibril whole protein shared immunologic determinants with normal human serum prealbumin (transthyretin), but revealed subtle differences on immunoelectrophoresis and radial immunodiffusion. On sodium dodecyl sulfate‐polyacrylamide gel electrophoresis, amyloid fibril whole protein was resolved into numerous bands that reacted with antitransthyretin on immunoblots. The whole protein also contained peptide fragments of fibronectin, but was devoid of amyloid P protein. An antiserum raised against the whole protein was suitable for immunocytochemistry of amyloid in paraffin sections. In contrast, commercial antitransthyretin, raised against the intact tetrameric protein failed to react with tissue amyloid. Immunochemical and immunocytochemical results support the concept that familial amyloid polyneuropathy with cardiomyopathy is due to infiltration of susceptible tissues by an anomalous transthyreti

ISSN:0148-639X    

DOI:10.1002/mus.880080902

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

年代:1985

数据来源: WILEY

摘要:

AbstractMyofiber suspensions with 80% viability (morphological intactness) were prepared from rat m. flexor digitorum brevis by a 6‐hour collagenase treatment. The viable fibers had intact sarcolemmas and generally showed continuous basal laminae. The intracellular compartments exhibited normal muscular morphology. The suspended myofibers showed good tolerance against extracellular calcium (up to 30 mM), but were susceptible to 15mMEGTA. Calcium ionophore A23187 induced contraction, with loss of viability in both calcium‐containing and nominally calcium‐free Krebs‐Ringer medium. EGTA prevented the ionophore effect, but the muscle cells collapsed as soon as calcium was replenished. A calcium paradox, as observed with perfused heart, could not be induced in isolated skeletal myocytes. This suspended cell system should provide a useful tool for investigating relationships between metabolic parameters and muscle physiology. The extracellular environment can be manipulated easily, and cellular responses of individual skeletal muscle fibers can be measured and vis

ISSN:0148-639X    

DOI:10.1002/mus.880080903

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

年代:1985

数据来源: WILEY

摘要:

Abstract31P nuclear magnetic resonance (NMR) was used to investigate the resting energy metabolism of the calf muscle in boys with Duchenne's muscular dystrophy. Reductions in the phosphocreatine/adenosine triphosphate (PCr/ATP) and the PCr/Pi ratios were found, but ATP as a fraction of the total mobile phosphorus signal was not reduced, and intracellular pH was normal in the Duchenne muscle. Attempts at quantitation of the NMR signal suggested that the reduced total phosphorus signal seen in the Duchenne muscle was a result of muscle fiber loss only and that the muscle fiber ATP concentration was probably normal in the diseased tissue. An exercise study in one 7‐year‐old boy with Duchenne's dystrophy demonstrated that the muscle had a normal ability to break down and resynthesize phosphocreatine. Presented here are the first reported trials of the effects of two putative therapeutic agents on energy metabolism determined by NMR in Duchenne's muscular dystro

ISSN:0148-639X    

DOI:10.1002/mus.880080904

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

年代:1985

数据来源: WILEY

摘要:

AbstractMuscle conduction velocity and mean frequency of the electromyogram (EMG) spectrum were measured simultaneously in the biceps brachii muscles of nine healthy subjects during sustained isometric contraction. Recordings were made at 60% and 70% of the maximum voluntary contraction In all subjects, both conduction velocity and mean frequency decreased during the time period of the fatiguing contractions. Also, the muscle conduction velocity was found to vary linearly with the mean frequency. This demonstrates that the EMG spectral shifts observed during muscle fatigue are due to slowing of the conduction velocity.

ISSN:0148-639X    

DOI:10.1002/mus.880080905

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe total creatine content of rat extensor digitorum longus (EDL) muscles is reduced from 26.7 m̈mol·g−1to 5.2 m̈mol·g−1after 4 weeks on a diet containing b̃‐guanidinopropionate. The resting muscles of these animals contain only 5% of the normal creatine phosphate and about 30% of the normal adenosine triphosphate (ATP). Isometric twitch and brief tetanic responses are not significantly different from normal. However, following a 1‐second tetanus, the normal twitch potentiation (+80%) is reversed in depleted muscles (−40%). The initial suppression lasts 1–2 seconds and is followed by a small delayed potentiation (+25%). Relaxation rate, which is normally increased following a tetanus, is considerably reduced in depleted muscles. Reversal of potentiation appears to be due to a suppression of twitch activation. The suppression may result from a transient fall in ΔGATP, which is thought to be a critical parameter in the uptake of Ca++by the sarcoplasm

ISSN:0148-639X    

DOI:10.1002/mus.880080906

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

年代:1985

数据来源: WILEY

摘要:

AbstractSerum from a 2‐year‐old male Belgian sheepdog with eosinophilic myositis, which particularly affects the masticatory muscles, was tested for the presence of muscle‐specific autoantibodies. Control type 2 temporalis muscle fibers were selectively stained following incubation with the patient's serum and staphylococcal protein A conjugated to horseradish peroxidase (SPA‐HRPO). Likewise, type 2 fibers in the patient's temporalis muscle were selectively stained with SPA‐HRPO. The same staining procedures applied to limb muscle did not result in fiber staining. Proteins isolated from the temporalis and triceps brachii muscles of a normal dog were separated under denaturing conditions by onedimensional sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. The separated proteins were transferred onto nitrocellulose paper and incubated with either sera from the patient, normal dogs, or neuromuscular disease controls. Subsequent incubation with peroxidase‐conjugated goat anti‐dog lgG demonstrated antibodies to at least four proteins of the temporalis muscle (myosin heavy chain and three unidentified proteins) when incubated with the patient's serum but not with the controls. Under all conditions, antibodies to the proteins of the triceps brachii were not detected. These findings establish the presence of autoantibodies to specific temporalis muscle proteins that may initiate the myonecrosis and inflammatory response as well as limit the distribution

ISSN:0148-639X    

DOI:10.1002/mus.880080907

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

年代:1985

数据来源: WILEY

摘要:

AbstractTwo cases of botulism with autonomic and neuromuscular system involvment are presented. In both patients, dryness of the mouth and difficulties in swallowing were predominant symptoms. Esophageal manometry revealed a marked decrease in peristaltic amplitude, which was most pronounced in the upper third of the esophagus. These functional abnormalities returned to normal following recovery from the acute disease.

ISSN:0148-639X    

DOI:10.1002/mus.880080908

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

年代:1985

数据来源: WILEY

摘要:

AbstractChronic low‐frequency stimulation of a fast skeletal muscle effects a transition of myosin isozymes from those characteristic of a fast muscle to those characteristic of a slow muscle. This transformation involves changes in both myosin heavy and light chains. During development, muscles usually change directly from embryonic to neonatal to fast or from embryonic to neonatal to slow isozymes. We have questioned whether chronic stimulation of the adult fast muscle results in a direct fast‐to‐slow isozyme shift or whether transformation requires reexpression of the developmental isozymes prior to the synthesis of adult slow isozymes. We have examined these alternatives in the chronically stimulated dog diaphragm using adenosine triphosphatase (ATPase) histochemistry, pyrophosphate gel electrophoresis of native isozymes, peptide mapping of myosin heavy chains, immunoblotting with an antibody specific to embryonic myosin heavy chain, and solid‐phase radioimmunoassay. We have demonstrated that a transition from adult fast to adult slow isozymes during chronic stimulation does not involve a recapitulation of embryonic i

ISSN:0148-639X    

DOI:10.1002/mus.880080909

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

年代:1985

数据来源: WILEY

ISSN:0148-639X    

DOI:10.1002/mus.880080910

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

年代:1985

数据来源: WILEY

ISSN:0148-639X    

DOI:10.1002/mus.880080911

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

年代:1985

数据来源: WILEY