摘要:

AbstractA 66‐year‐old professional golf instructor developed pain, numbness, and weakness in an ulnar distribution, but the lesion could not be localized to either elbow or wrist by routine nerve conduction techniques. Stimulation along serial 1‐cm increments in the distal forearm disclosed a point of focal conduction block approximately 7 cm proximal to the ulnar styloid. At surgery, the flexor carpi ulnaris was enlarged, with muscle fibers extending all along the normally tendinous distal portion. A dense fibrovascular band coursed from the ulnar artery to the abnormal muscle, compressing the adjacent ulnar nerve. Intraoperative electroneurography precisely localized the area of conduction abnormality and helped identify the band as the compressing structure. Within 2 months following surgical decompression there was complete resolution of conduction block with excellent clinical rec

ISSN:0148-639X    

DOI:10.1002/mus.880120502

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe influence of melanocortins on the process of collateral sprouting has been investigated in rat soleus muscle. The soleus muscle was partially denervated by transecting and ligating the L5 mixed nerve. Collateral sprouting was assessed by means of isometric twitch tension measurements of soleus motor units that remained following L5 transection. The smaller the number of remaining soleus motor units, the larger the extent of collateral sprouting. Seven days following partial denervation, the index of sprouting (ratio between twitch tension of motor units in partly denervated muscles and in normal muscles) was significantly increased by treatment with the ACTH4–9analog Org.2766 (1 μg/48 hours). This increase appeared to be present also 28 days following partial denervation. The electrophysiological results were confirmed by histological investigations. The results provide evidence that Org.2766 increases the motor neuron collateral sprouting capacity of peripheral nerve. Org.2766 did not induce muscle fiber hypertrop

ISSN:0148-639X    

DOI:10.1002/mus.880120503

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

年代:1989

数据来源: WILEY

摘要:

AbstractColchicine may produce a neuromuscular disorder even when given in customary doses. We report the electrodiagnostic features in eight pathologically proven cases of colchicine‐induced myoneuropathy. Myopathic motor unit potentials and early recruitment were found in proximal limb and truncal muscles, frequently with fibrillations, positive sharp waves, or complex repetitive discharges. These electromyographic findings correlated with the course of the weakness, which rapidly resolved within weeks of drug discontinuation, indicating that the major functional disturbance in the patients was myopathy. The accompanying signs of axonal neuropathy persisted longer, with little functional consequence. Although often misrecognized as polymyositis, colchicine myoneuropathy was identifiable by the rapid clinical and electrophysiologic improvement following drug withdrawal as well as by its distinctive morpholog

ISSN:0148-639X    

DOI:10.1002/mus.880120504

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

年代:1989

数据来源: WILEY

摘要:

AbstractWe have carried out a comparative study of caffeine sensitivity of the sarcoplasmic reticulum (SR) of fast and slow normal human fibers chemically skinned. Human slow‐fiber SR is more sensitive to caffeine than fast fiber SR; however, it releases less calcium and at a lower rate than the SR of fast fibers when exposed to threshold concentrations of caffeine. These results indicate that the SR calcium release mechanisms of SR of fast and slow human fibers are homologous but not identical. An increased sensitivity of SR to caffeine is found in both fast and slow fibers from human malignant hyperthermia muscle. However, fast fibers seem to be the most affected, since their caffeine threshold for contraction is very close to that of slow fiber

ISSN:0148-639X    

DOI:10.1002/mus.880120505

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

年代:1989

数据来源: WILEY

摘要:

AbstractVarious parameters of single‐ fiber electromyography (SFEMG) were studied in 19 patients with electrophysiologically and histologically proven chronic demyelinating neuropathy. The mean duration of disease at the time of testing was four years.Motor nerve conduction in the median nerve was abnormal in all patients, whereas sensory nerve conduction was abnormal in all but one. Needle EMG in the extensor digitorum communis (EDC) muscle showed rare fibrillations and fasciculations and some abnormal motor unit potentials in most of patients. SFEMG in the EDC muscle showed an increased fiber density in seven cases (37%) and minimally abnormal jitter in 14 cases (74%). Single‐fiber action potentials were stable, whereas blocking was rare. Fiber density was significantly increased in patients with fibrillation in the conventional needle EMG.Our study showed that the SFEMG is mildly abnormal in many patients with demyelinating neuropathy and that this test is useful in detecting and quantitating axonal degeneration in demyelinating neuropa

ISSN:0148-639X    

DOI:10.1002/mus.880120506

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

年代:1989

数据来源: WILEY

摘要:

AbstractA 51‐year‐old man with proven adenosquamous carcinoma of the lung presented with clinically acute steroid myopathy. Postabsorptive whole body leucine kinetics and fractional mixed muscle protein synthesis rate (MPSR) were determined by a steady‐state approach during continuous L‐(1–13C) leucine infusion. Plasma13C α‐ketoisocaproic acid enrichment was taken to represent labeling of the precursor pool. Postabsorptive whole body leucine flux and protein synthesis were less than the 1 in 500 confidence intervals of control values. Fractional MPSR was significantly reduced (P<0.01). Simultaneous calculation of MPSR from two adjacent sites was in excellent agreement (0.0372 and 0.0395% h−1). This is the first report that steroid myopathy is associated with reduced whole body protein synthesis and fraction

ISSN:0148-639X    

DOI:10.1002/mus.880120507

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

年代:1989

数据来源: WILEY

摘要:

AbstractComparisons have been made between torque (isometric and isokinetic), electrophysiological (SFEMG, Macro EMG), and muscle fiber characteristics in the vastus laterlis muscle of both legs in healthy subjects aged between 20 and 70 years. Torque was greater in males and decreased with age in both sexes. Multifactorial analysis showed a positive correlation between torque, body surface area, and mean fiber area. These variables explained only about 30–40% of the torque changes. The electrophysiological parameters (Marco EMG amplitudes and fiber density) revealed evidence of reinnervation, indicating preceeding denervation and therefore loss of motor units. It was concluded that this fall out of motor units also contributes to the reduction in torque, when compensatory reinnervation begins to fall. Other factors, such as reduction in muscle fiber contractility, metabolic factors, and central factors, may also play a role in age‐related reduction in tor

ISSN:0148-639X    

DOI:10.1002/mus.880120508

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

年代:1989

数据来源: WILEY

摘要:

Abstract31Phosphorus‐NMR spectroscopy may have the potential to help in the noninvasive diagnosis of malignant hyperpyrexia (MH). Changes in the phosphate‐metabolite profile of MH‐susceptible (MHS) skeletal muscle occur more readily under conditions of anoxia than in control muscle. Induction of anoxia caused a rapid fall in intracellular phosphocreatine, an elevation of inorganic phosphate, and finally a diminution of ATP in MHS muscle. The onset of metabolic change was slower in control tissue. Increased oxygen consumption may occur in anoxic MHS muscle, which leads to accelerated glycolysis and a rapid fall in the intracellular high‐energy phosphates. In MHS muscle an abnormality may exist in carbohydrate metabolism linked with poor resynthesis of the high‐energy phosphates, which may be precipitated under anaerobic conditions. Accelerated muscle metabolism is also observed in the presence of 2 mMcaffeine and 3% halothane in MHS muscle. Changes in the concentrations of metabolites could be mapped noninvasively under anoxic conditions using topic

ISSN:0148-639X    

DOI:10.1002/mus.880120509

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

年代:1989

数据来源: WILEY

摘要:

AbstractNeurophysiologic evidence of median nerve entrapment in the carpal tunnel was present in 25% of patients with late Lyme borreliosis. Sixty‐eight of 76 consecutive, prospectively studied patients with late Lyme underwent neurophysiologic testing. Nineteen reported intermittent hand paresthesias; 17 had neurophysiologically confirmed carpal tunnel syndrome. This was not consistently associated with clinically apparent wrist arthritis or with neurophysiologically evident peripheral neuropathy. We conclude that a significant proportion of patients with late Lyme borreliosis develop carpal tunnel syndrom

ISSN:0148-639X    

DOI:10.1002/mus.880120510

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

年代:1989

数据来源: WILEY

摘要:

AbstractWhole muscle grafts were made between mdx and normal mice to investigate whether the mdx myopathic lesion is intrinsic to mdx muscle or is a property of its environment. Grafts were examined between 20 and 101 days. Unequivocal necrotic muscle fibers and/or newly formed basophilic myotubes were noted in 8 of 16 grafts of mdx muscle made in normal hosts but in none of 16 grafts of normal muscle made in mdx hosts. In older grafts, the proportion of centrally nucleated fibers and variability of fiber diameter were both higher in mdx muscle grafted into normal hosts than in normal muscle grafted into either mdx or normal hosts. Analysis of the glucose‐6‐phosphate isomerase (GPI) isoenzyme content of the grafts indicated that the muscle formed was predominantly of donor origin. These findings provide evidence that the mdx lesion is a primary myopathy rather than secondary to an extramuscular primary les

ISSN:0148-639X    

DOI:10.1002/mus.880120511

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

年代:1989

数据来源: WILEY