摘要:

AbstractA newly developed technique for estimating the number of motor units in the biceps‐brachialis muscles and for studying the innervation patterns of motor units in the same muscles has been applied to the study of 17 patients with amyotrophic lateral sclerosis (ALS). Although severe motor unit losses were seen in many ALS cases, in most there were clear indications of increases in innervation densities, linked potentials, and blocking. This technique provides a powerful new tool for quantitatively assessing the extent of motor unit losses and the accompanying changes in innervation patterns in AL

ISSN:0148-639X    

DOI:10.1002/mus.880110502

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

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper presents a new method, here applied to the biceps‐brachialis muscles, for estimating motor unit numbers in healthy subjects. This method combines isometric contraction, intramuscular needle electrode recordings, and spike‐triggered averaging techniques to measure the sizes of motor unit potentials as recorded in the innervation zone with surface electrodes. The number of motor units is then estimated by division of the maximum biceps‐brachialis “M” potential recorded with the same surface electrodes and evoked by supramaximal stimulation of the musculocutaneous nerve, by the mean of at least 10 surface‐recorded motor unit potentials. The requisite intramuscular recordings provide additional information as to innervation density, incidence of linked potentials, and impulse blocking, phenomena that are particularly common in neurogenic and myogenic disoders. There was clear evidence of losses of motor units in older subjects: subjects over 60 years of age having approximately half the numbers of motor units of subjects under 60 y

ISSN:0148-639X    

DOI:10.1002/mus.880110503

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe muscle physiology and histochemistry of a hereditary neuromuscular syndrome of the mouse, “arrested development of righting response” (ADR), was studied. The speed of single twitches of fast ADR limb muscles was normal up to an age of about 60 days but decreased at later ages. At any age between 10 and 120 days postnatal, fast and slow muscles of the mutant displayed after‐contractions of 1–3 (5) seconds duration. These coincided with electrical after‐activity of muscle, as demonstrated by electromyography, After‐contractions and EMG signals were suppressed by the membrane‐stabilizing drug tocainide. These physiological data suggest that ADR is a myotonia. With a few exceptions, limb and trunk muscles of ADR animals showed a uniform oxidative phenotype with a lack of large diameter glycolytic fibers. The histochemical muscle phenotype of the ADR mouse was partially reversed by a long‐term treatment

ISSN:0148-639X    

DOI:10.1002/mus.880110504

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe hereditary neuromuscular syndrome of the mouse, “arrested development of righting response” (ADR), is characterized by after‐contractions of skeletal muscle. In order to analyze the etiology of this hereditary defect, mutant and wildtype muscle fibers were studied by intracellular recording. Direct stimulation of ADR muscle fibers elicited runs of action potentials of 1–5 seconds duration, with declining amplitudes and varying frequencies. The electrical after‐activity coincided with after‐contractions of the fiber, and both phenomena could be suppressed by the membrane‐stabilizing drug tocainide. Since similar runs of APs were observed with wildtype muscle in chloride‐free medium, the possible involvement of chloride conductance in the ADR syndrome was studied. Although membrane time constants in wildtype muscle were 4 times prolonged in chloride‐free medium, those of ADR muscle were only 1.4 times longer. This finding indicated a drastic reduction of chloride conductance of the ADR muscle membrane. We conclude that ADR is a myotonia, related in its etiology to hereditary

ISSN:0148-639X    

DOI:10.1002/mus.880110505

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

年代:1988

数据来源: WILEY

摘要:

AbstractA nerve conduction method is demonstrated for cranial nerve XII, the hypoglossal nerve. Submandibular surface stimulation is performed while recording over the anterior surface of the tongue. There were 30 normal adult subjects and 60 hypoglossal nerves studied. Evoked response parameters are reported as follows: mean latency 2.2 ± 0.4 msec, mean amplitude 3.8 ± 1.6 mV (baseline to peak, best of 5 responses). This nerve conduction method is reliable and should expand the electrophysiological assessment of XII cranial nerve motor functio

ISSN:0148-639X    

DOI:10.1002/mus.880110506

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe association of malignant hyperthermia (MH) with neuromuscular disorders has been recognized since 1970. These disorders include central core disease, Duchenne muscular dystrophy, myotonia congenita, myotonic dystrophy, nonspecific myopathies, and King–Denborough syndrome. In order to assess the anesthetic risk of MH in the neuromuscular population, we performed halothane and caffeine contracture testing for MH susceptibility on biopsied muscle removed from 25 consecutive neuromuscular patients during diagnostic evaluation. Positive contracture tests were found in 7 to 18 patients with myopathic disorders and 3 to 7 patients with neurogenic disorders. Two of our patients had anesthetic events suggesting MH. These findings suggest that myopathic and neuropathic disorders share pathogenic mechanisms with MH, resulting in positive contracture tests and possibly leading to clinical events during anesthesia. Although there is controversy regarding the interpretation of a positive contracture test, contracture testing remains the most widely accepted test for MH susceptibility. Thus, a variety of neuromuscular disorders may be associated with MH susceptibility, and caution should be exercised during anesthesia in this group of patient

ISSN:0148-639X    

DOI:10.1002/mus.880110507

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

年代:1988

数据来源: WILEY

摘要:

AbstractDorsiflexion of one unloaded hind limb caused hypertrophy of the soleus relative to weight‐bearing controls and faster growth of the plantaris and gastrocnemius muscles relative to the contralateral freely moving muscles. Unloading of the soleus muscle diminished primarily myofibrillar proteins whereas stretching increased all proteins. Stretching the soleus increased RNA, accelerated, especially, in vitro synthesis of sarcoplasmic proteins, and diminished in vitro proteolysis. Both in vivo and in vitro results showed slower synthesis and faster degradation in the freely moving than in the weight‐bearing soleus muscle, faster synthesis and slower degradation in the stretched than in the freely moving soleus muscle, and faster degradation in the stretched than in the weight‐bearing soleus muscle. Hence, stretching of the soleus muscle prevented changes in mass and protein metabolism produced by unloading. Shortening of the extensor digitorum longus muscle produced less muscle growth, slowed in vitro protein synthesis, and lowered RNA relative to the contralateral, freely moving m

ISSN:0148-639X    

DOI:10.1002/mus.880110508

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe ulnar nerve normally enters the flexor carpi ulnaris (FCU) proximally and anteriorly between the humeral and ulnar heads of the muscle. After an intramuscular course of several centimeters, the nerve exits the FCU distally to lie in a tissue plane between the FCU and the flexor digitorum profunds (FDP). A patient with ulnar neuropathy studied by intraoperative electroneruography demonstrated major focal conduction block at the point where the nerve exited the FCU. A fivefold increase in amplitude and reversal of a dispersed, irregular compound muscle action potential to a more normal configuration occurred with stimulation just distal to the point of exit. There was no evidence by inspection, probing, or electroneurography of compression in the retrocondylar groove or at the cubital tunnel. In a series of 100 cadaver dissections, the intermuscular septum between FCU and FDP was thick and tough in several specimens. This septum may represent a site of ulnar nerve entrapment.

ISSN:0148-639X    

DOI:10.1002/mus.880110509

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe membrane lipid and fatty acid composition of red blood cell ghosts from three paramyotonia patients was investigated. Cholesterol and total phospholipid contents were not different from the controls, but the sphingomyelin content was reduced, and this was compensated for by an increase in phosphatidylcholine. Thus, the molar ratios of phosphatidylcholine/sphingomyelin and phophatidylcholine/phosphatidylethanolamine were greater than normal. The saturated fatty acids in the total phospholipids were increased so that the ratio of saturated/unsaturated fatty acids was 1.4–1.6 versus 1.1–1.2 in the controls. The polyunsaturated fatty acids comprised only 22–26% of the fatty acids versus 31–32% in controls. The reduction in content of unsaturated fatty acids concerned all phospholipid classes in one patient and only the choline phospholipids in the two other patients who were related to each other. The pattern of the fatty acids in the C2‐position of the glycerophospholipids reflected the finding in the total phospholipids. Thus, an alteration of the activity of the acyl‐CoA: 1‐monoacylphosphoglyceride‐acyltransferase seems unlikely. The results support the notion of a generalized membrane defect in paramyotonia congenita, although the degree of abnormality in the fatty acid pattern was not correlated with the severity of the cl

ISSN:0148-639X    

DOI:10.1002/mus.880110510

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

年代:1988

数据来源: WILEY

摘要:

AbstractWe studied 10 patients with late onset spinocerebellar ataxia including electrophysiological and muscle biopsy examinations. Nerve conduction studies of eight patients revealed axonal neuropathy, and six cases also showed signs of the involvement of the lower motor neuron. In 9 patients quantitative analysis of single motor unit potentials (MUPs) of the tibialis anterior or biceps brachii muscles showed mild to severe neuropathic changes and in all 10 patients the histopathological examination of the tibialis anterior showed mild to severe neuropathic changes. Neither nerve conduction studies, quantitative MUP analysis, nor histological findings of the muscle were related to the severity or duration of the disease.

ISSN:0148-639X    

DOI:10.1002/mus.880110511

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

年代:1988

数据来源: WILEY