摘要:

AbstractFive electrical characteristics—impedance, broadband noise generation, line interference sensitivity, signal distortion, and common‐mode conversion—were measured in five electromyographic (EMG) concentric needle electrodes (CNEs) from each of six commercial manufacturers. Untreated CNEs showed considerable variation in impedance and broadband noise characteristics, both within and among manufacturers. Electrolytic treatment reduced impedances by a factor between 1.5 and 4.0 and lessene within manufacture variability Average post‐treatment impedances at 100Hz ranged from 31 to 436 kOhms, reflecting in part the range of core surface areas. Treatment also reduced the broadband noise to the level of the instrumentation noise for all but the highest impedance CNEs. Distortion and common‐mode conversion were negligible for the lowest impedance CNEs. Line interference from a nearby power cord was completely suppressed only by those CNEs with fully shielded cables, and then only when the electromyographer also was grounded; there was no measurable benefit when the shield was driven, as opposed to grounded. We conclude that (1) there are consistent differences in the properties of CNEs from different manufacturers, reflecting differences in materials, design, and construction; (2) electrolytic treatment temporarily improves the performance of all CNEs, and tends to lessen the differences among them, most likely through a surface electrochemical effect; and (3) both active and passive cable shields are effective in reducing extraneous line int

ISSN:0148-639X    

DOI:10.1002/mus.880080102

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe localization of myoglobin (Mb) in skeletal muscle in various neuromuscular diseases was studied by an immunoperoxidase technique. The immunoreactivity of Mb was shown to be well preserved in muscle fibers that showed denervation atrophy or vacuolar degeneration, as well as in muscle fibers with apparently normal structure. Marked decrease or loss of Mb immunoreactivity was observed in muscle fibers with hyaline degeneration or floccular necrosis, where there was irreversible disruption of the muscle fibers. On the other hand, regenerated fibers showed variable immunostaining for Mb. Most regenerated fibers showed little or no immunostaining but some showed staining as strong as apparently normal fibers. These findings in various neuromuscular diseases suggested that the elevation of serum Mb in patients with these diseases was ascribed to its release from severely injured, necrotic muscle fibers. The immunohistochemistry for Mb was shown to be useful to evaluate plasma membrane injury and characterize muscle degeneration.

ISSN:0148-639X    

DOI:10.1002/mus.880080103

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

年代:1985

数据来源: WILEY

摘要:

AbstractAcute myopathy in conditions associated with endogenous or druginduced potassium loss has been reported. We describe six patients with potassium depletion myopathy (P‐DM). The clinical picture included flaccid muscle weakness without sensory loss, myalgia, polyuria, and polydipsia. All the cases had markedly increased serum creatine kinase (CK) levels. The most consistent pathological characteristics were phagocytosis of degenerating muscle fibers plus fiber regeneration. Atrophy of type 2 fibers was observed. Vacuoles and vesicular elements originating from T‐tubules were also encountered. The clinical manifestations and morphological changes had reversed after potassium repletion. Both constriction of vascular smooth muscle and cellular energy failure may be pathogenetic factors in P

ISSN:0148-639X    

DOI:10.1002/mus.880080104

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

年代:1985

数据来源: WILEY

摘要:

AbstractCreatine phosphate (CrP), adenosine triphosphate (ATP), creatine kinase (CK), adenylate kinase (AK), protein, and DNA were quantified in human muscle cell cultures undergoing transition from dividing myoblasts to multinucleate myotubes. CrP is negligible in cultures grown in commonly applied media but increases rapidly when sufficient exogeneous creatine is available. The rise in CrP content precedes the rapid increase of CK and cessation of DNA synthesis found during cell fusion. The addition of creatine has no significant effect on the CK and protein content and on the fusion of the human muscle cells. ATP, AK, and protein increase gradually during proliferation and differentiation. When expressed per milligram of protein, ATP and AK are in the same range as in human skeletal muscle and are not correlated to the cell fusion. In contrast, CrP and CK per milligram protein are much higher in myotubes than in myoblasts but remain much lower than in muscle. These data indicate that only an early differentiation phase has been reached in the muscle cell cultures.

ISSN:0148-639X    

DOI:10.1002/mus.880080105

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe endoneurial fluid potassium [K+]ehas potent effects on membrane potential and excitability but direct measurements have not been reported. The [K+]ewas measured with K+ion‐sensitive microelectrodes in normal, demyelinated, and regenerating rat peripheral nerve fibers. The mean value in normal nerve was 3.7 mM. The [K+]ewas consistently elevated in regenerating nerves and infrequently elevated in demyelinated nerves. The time course of [K+]ewas studied in the left tibial nerve of 22 rats 2 days to 3 months in the extended crush model. The [K+]ewas increased and peaked in the first 2 weeks, with a progressive decline toward control values after that. Single fiber recordings were made from the tibial division of the sciatic nerve in 13 animals. The mean number of single fibers studied per rat was 55.5 (SD 24.6). Spontaneous activity (SA) was present in all regenerating nerves and was maximal in the first 2–4 weeks. Endoneurial K+was further increased by intraarterial injection of potassium into the saphenous artery. Spontaneous activity was enhanced when [K+]ebegan to rise; there were further superimposed bursts of SA with the administration of additional boluses. These findings suggest that [K+]eincrease is a factor in enhancing SA in damaged nerve fib

ISSN:0148-639X    

DOI:10.1002/mus.880080106

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

年代:1985

数据来源: WILEY

摘要:

AbstractWe investigated the effect of denervation on the concentration of total, free, and acyl carnitine in the soleus (S), extensor digitorum longus (EDL), and anterior tibial (AT) muscles of the rat. Soon after denervation there was a marked decrease in total carnitine in all three muscles. Acyl carnitine levels decreased concomitantly with changes in total carnitine. In control but not in denervated muscle, the carnitine concentration was age‐dependent during the period of rapid growth of the animals. The highest carnitine concentration was observed at 14 weeks of age. The results of this study suggest that normal innervation significantly influences carnitine‐mediated lipid metabolism in skeletal mus

ISSN:0148-639X    

DOI:10.1002/mus.880080107

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

年代:1985

数据来源: WILEY

摘要:

AbstractSensory and/or motor nerve conduction velocities (NCVs) were measured in median, radial, sural, and peroneal nerves of 54 healthy girls and 75 healthy boys aged 3–19 years. Independent of the nerve and sex, both motor and sensory NCVs increased in the upper extremities and decreased in the lower ones as a function of age/growth in length. NCV increased in the upper limbs on an average 3.17 m/sec in the boys and in the girls 1.47 m/sec per 10 years of life. As for the nerves of the lower extremities, NCV slowed down on the average 1.81 m/sec in the boys and in the girls 3.62 m/sec per 10 years of age. The change varied in different nerves. A highly significant one (P<0.001) was found in both the motor and sensory NCVs of peroneal nerve in the girls and in the sensory NCV of radial nerve in boys. On the average NCV was in most nerves faster in the girls than in boys of the same age. According to these results, changes occur in the function—and thus probably also in the morphology—of peripheral nerves even in later childhood and adolescence. These changes pertain to general maturation, growth in length of the limbs, and possibly als

ISSN:0148-639X    

DOI:10.1002/mus.880080108

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

年代:1985

数据来源: WILEY

摘要:

AbstractThe regenerative capacity of the cervical anterior horn cells was studied at 4 and 7 days following forelimb nerve crush in 19 Wobbler mice and 18 normal littermates. Quantitative histologic and radiolabeled axonal transport techniques showed that the axotomized neurons of the wobbler mouse supported active axonal elongation. However, the average axon outgrowth rate determined by histologic technique was diminished by 25% and the fastest axon outgrowth rate determined by axonal transport technique was also decreased by 30% in wobbler mice as compared to controls. The distal labeled peak was absent in the wobbler mouse at 7 days, indicating that the regeneration rate of individual axons was widely dispersed. Histologic studies also showed that the wobbler axons grew slowly. This study suggests that axonal regeneration does occur in motor neurons undergoing a primary neuronopathy. However, the regenerative capacity was reduced and this appears to reflect an impairment of functional integrity in the anterior horn cells of the wobbler mouse.

ISSN:0148-639X    

DOI:10.1002/mus.880080109

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

年代:1985

数据来源: WILEY

摘要:

AbstractFine granular (hyaline) intranuclear inclusion bodies were found in perivascular cells of a muscle and a sural nerve biopsy from a 32‐year‐old woman with slowly progressive motor disturbances. The hyaline nuclear inclusion bodies could be distinguished from other intranuclear hyaline inclusions by their granularity, the size of the granules (approximately 5–15 nm), and the positive iron staining reaction. They were not seen in muscle fibers or Schwann cells. Because of these apparently pathognomonic structural features the patient appears to present a condition that has not been described b

ISSN:0148-639X    

DOI:10.1002/mus.880080110

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

年代:1985

数据来源: WILEY

摘要:

AbstractWe have determined the value of creatine and pyruvate kinase (CK and PK) in carrier detection by evaluating 811 females in 73 families participating in the Collaborative Investigation of Duchenne Dystrophy. Thirty‐nine obligate carriers, 244 normal controls (paternal females), as well as 76 possible carriers and 351 carrier suspects had three CK and PK specimens analyzed at a central laboratory. The CK and PK values varied with age in normals: both fell with age early in life, and CK rose after the fifth decade. Discriminant analysis indicated that the combination of mean CK and PK corrected for age yielded the best data for calculation of carrier probability. Using the best model, only 45% of obligate carriers could be identified at a false‐positive rate of 2.5%. Daughters of obligate carriers have a disproportionate decline in CK and PK with age as compared to noncarrier females, suggesting that the rate of carrier detection will be higher in the first two decades. Our low rate of carrier detection, as compared to other studies, may reflect both the age of our obligate carrier population and the use of a control group that is more representative of the carrier populat

ISSN:0148-639X    

DOI:10.1002/mus.880080111

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

年代:1985

数据来源: WILEY