摘要:

AbstractEleven patients with progressive weakness following polio (postpoliomyelitis muscular atrophy syndrome) were compared electromyographically with nine patients who had stable strength following polio. Abnormalities included (1) abnormal motor unit characteristics in many muscles indicating widespread loss of motor neurons and reinnervation in muscles, including many not clinically affected by the polio; (2) prevalent spontaneous denervation potentials; and (3) abnormalsingle‐fiber electromyographic jitter. These electromyographic abnormalities were similar in progressive and stable postpoliomyelitis patients even when muscles were separated by strength, stability, age and duration of the postpoliomyelitis state. Postpoliomyelitis muscular atrophy appears to be the clinically apparent end of the spectrum of abnormalities existing in all postpoliomyelitis patient

ISSN:0148-639X    

DOI:10.1002/mus.880130802

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

年代:1990

数据来源: WILEY

摘要:

AbstractA number of phosphoproteins were found in the soluble fraction of rat skeletal muscle by two‐dimensional polyacrylamide gel electrophoresis (PAGE). The pattern of some of these phosphoproteins differed in fast (extensor digitorum longus, EDL) or slow (soleus) muscles, was dependent on normal innervation, and was altered with denervation. In order to determine if the pattern was maintained by electrical activity or trophic factors, we compared the effect of electrical block by local neural application of tetrodotoxin with the effect of complete nerve section. Both methods produced similar alterations in phosphoproteins, indicating that the pattern is dependent on nerve activity, not trophic factors. Such phosphoproteins are possible mediators of neural activity on gene expressio

ISSN:0148-639X    

DOI:10.1002/mus.880130803

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe influences of coil position and coil–nerve distance on compound muscle action potentials (CMAPs), recorded from the first dorsalinterosseus muscle during magnetic stimulation of the brachial segment of the ulnar nerve, were studied in 10 healthy volunteers. A 14‐cm coil was held tangentially to the skin with the center overlying the nerve. Mapping of the CMAP latencies and amplitudes was made as the coil was displaced laterally in steps of 1 cm and in planes 0–3 cm from the skin surface. Stimulation with the coil center positioned 3 cm laterally to the nerve with the coil current directed proximally yielded the largest amplitudes with minimal variability and the most constant relationship to electrically evoked CMAPs. In this position the interindividual and intraindividual reproducibility of the magnetically evoked latencies were at least as good as those of electric stimulation when coil–skin distance was

ISSN:0148-639X    

DOI:10.1002/mus.880130804

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

年代:1990

数据来源: WILEY

摘要:

AbstractWe measured acetylcholinesterase (AChE) in the non‐endplate region of rat muscle, documenting its intrinsic activity within muscle fibers, as well as the extrinsic level in the capillaries and endomysium. When each muscle was considered as a whole, intrinsic AChE activity detected within the fibers was stronger in the fast‐twitch extensor digitorum longus than in the slow‐twitch soleus. Analysis of individual muscle fibers also showed the same tendency with a higher value in the fast‐twitch type II fibers than in the slow‐twitch type I fibers. On the average, 73% of the fibers showed intermediate or strong enzymatic activity in the fast‐twitch muscle, whereas 56% of the slow‐twitch muscle had only low activity. Sectioning or ligation of the sciatic nerve resulted in nearly complete abolition of the enzyme in the non‐endplate region of the denervated muscles within 7 days, suggesting that nerve transmission regulates AChE activity not only in the endplate, as is well known, but also outside this region. Human skeletal muscles showed the same pattern of AChE activity in the non‐endplate region as se

ISSN:0148-639X    

DOI:10.1002/mus.880130805

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

年代:1990

数据来源: WILEY

摘要:

AbstractSpike‐triggered averaging (STA) has been used to extract twitch profiles of single motor units (SMU) within the human masseter muscle. However, the reported twitch tensions may have been biased by thevoluntary firing frequency of the SMUs, the complex architecture ofthe muscle, and by the biomechanical linkage of the jaw. In this study, a rigid STA paradigm was used to record spike‐triggered “measured tensions” (STMTs) for 32 SMUs in the masseter musclesof four subjects. STMTs were recorded at two different orientations of a force transducer placed between the incisor teeth. The STMTs produced by each unit were used to calculate jaw torque. STMTs were also recorded in 11 units with differing degrees of muscle coactivation. STMTs for each unit varied according to the orientation of the force transducer. However, no systematic changes in STMTs occurred with reciprocal changes in the jaw moment arm. STMTs could be altered significantly by different degrees of muscle co‐activation. The use of STA as a method for determining SMU tension in the human masseter muscle appears to be highly task‐dependent and in the presence of co‐activation may be

ISSN:0148-639X    

DOI:10.1002/mus.880130806

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

年代:1990

数据来源: WILEY

摘要:

AbstractWe report a patient who presented with involvement of multiple cranial nerves associated with otherwise typical neuralgic amyotrophy. This syndrome of unknown etiology is not limited to the brachial plexus. Simultaneous involvement of cranial nerves IX, X, XI, and XII is a unique presentation. The electrophysiological data indicate the presence of a multifocal neuropathy.

ISSN:0148-639X    

DOI:10.1002/mus.880130807

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

年代:1990

数据来源: WILEY

摘要:

AbstractWe studied a patient with no prior history of neuromuscular disease who became virtually quadriplegic after parenteral magnesium administration for preeclampsia. The serum magnesium concentration was 3.0 mEq/L, which is usually well tolerated. The magnesium was stopped and she recovered over a few days. While she was weak, 2‐Hz repetitive stimulation revealed a decrement without significant facilitation at rapid rates or after exercise, suggesting postsynaptic neuromuscular blockade. After her strength returned, repetitive stimuation was normal, but single fiber EMG revealed increased jitter and blocking. Her acetylcholine receptor antibody level was markedly elevated. Although paralysis after magnesium administration has been described in patients with known myasthenia gravis, it has not previously been reported to be the initial or only manifestation of the disease. Patients who are unusually sensitive to the neuromuscular effects of magnesium should be suspected of having an underlying disorder of neuromuscular transmissio

ISSN:0148-639X    

DOI:10.1002/mus.880130808

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

年代:1990

数据来源: WILEY

摘要:

AbstractExtensores digitorum longi of rats, infarcted and denervated by different surgical procedures, were used to analyze by biochemical and cytochemical methods the acetylcholinesterase (AChE) changes during muscle degeneration, regeneration, and early or delayed reinnervation. Biochemical tests showed that the regenerating muscle produces globular AChE forms (36% of controls) and small amounts of A12 (16S) asymmetric from (5% of controls); at the end of the regeneration, innervation and electromechanical function are required for the complete recovery of globular forms, and are absolutely critical to prevent A12 (16S) disappearance. Cytochemical observations showed that, unlike nicotinic receptor, AChE deposited at the neuromuscular junction before ischemic necrosis is protected from breakdown, as is the basal lamina of muscle fibers. Taken together, these observations contribute to the understanding of the factors that play a critical role in muscle repair and are, therefore, of clinical relevance.

ISSN:0148-639X    

DOI:10.1002/mus.880130809

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe incidence of an elevated creatine kinase (CK) in a group of polio patients with delayed weakness (15/29) did not differ from polio patients without delayed weakness (9/31) or others with amyotrophic lateral sclerosis (ALS; 10/21). Mean CK in polio patients withoutdelayed weakness (151 IU/L) was lower than the CK in those with delayed weakness (270 IU/L) or ALS (224 IU/L) (P>0.05). An elevated CK in polio patients with delayed weakness did not correlate with new or residual weakness. These findings suggest that muscle overuse is either not important or inadequately measured by CK. Widely distributed fibrillations were associated with an elevated CK for all polio patients combined (P>0.01). Fibrillations occurred in more muscles of polio patients with delayed weakness (P>0.01) and implies that late denervation may play a role in the development of newweakness in some polio patients.

ISSN:0148-639X    

DOI:10.1002/mus.880130810

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

年代:1990

数据来源: WILEY

摘要:

AbstractLambert‐Eaton myasthenic syndrome (LEMS) is an autoimmune disorder characterized by reduced acetylcholine release at the neuromuscular junction. We report a model of the disease developed by active immunization of rats with purely cholinergic nerve terminals (synaptosomes) isolated from theTorpedoelectric organ. Electromyographic studies of neuromuscular transmission in these rats showed a weak initial response followed by a pronounced incremental response to paired supramaximal stimuli (8 msec apart). There was no such response in control rats. There was no evidence of a postsynaptic transmission deficit in the synaptosomes immunized rats. We conclude that immunizing rats withTorpedocholinergic nerve terminals causes a specific presynaptic dysfunction and may serve as a model for the study of LEM

ISSN:0148-639X    

DOI:10.1002/mus.880130811

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

年代:1990

数据来源: WILEY