摘要:

AbstractIliofibularis muscles ofRana temporariawere minced and allowed to regenerate in the iliofibularis or the sartorius bed of the same frog. Regenerated muscles were examined for the presence of slow muscle fibers using electrophysiologic, histochemical, and contractile parameters. Muscle regeneration from sartorius mince was also studied. Regeneration was more successful from iliofibularis than from sartorius mince, and the iliofibularis bed was more favorable for regeneration than the sartorius bed for both types of muscle. Twitch fibers regenerated within a few months, but slow fibers could not be identified earlier than 14 months after muscle destruction. Slow muscle fibers regenerated only from iliofibularis mince, both orthotopically and heterotopically. All regenerates capable of maintaining a K‐contracture contained histochemically identified slow fibers; the membrane properties of electrophysiologically identified slow fibers were normal. It is concluded that slow muscle fibers regenerate only from the remnants of a muscle that contains slow fibers. The results are discussed with respect to the role of innervating nerve fiber

ISSN:0148-639X    

DOI:10.1002/mus.880080802

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

年代:1985

数据来源: WILEY

摘要:

AbstractA 62‐year‐old patient who had had acute paralytic poliomyelitis in early childhood developed bilateral lower limb muscle pseudohypertrophy. The pseudohypertrophy was caused primarily by an enormous excess of adipose tissue replacing muscle fibers, and, in part, by work hypertrophy of muscle fib

ISSN:0148-639X    

DOI:10.1002/mus.880080803

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

年代:1985

数据来源: WILEY

摘要:

AbstractForty‐three patients with myotonic dystrophy (MyD) and 43 age‐ and sex‐matched controls were prospectively evaluated for mitral valve prolapse (MVP) using both cardiac auscultation and echocardiography (ECHO). Prevalence of MVP was significantly increased in MyD patients when using either abnormal auscultation plus abnormal ECHO (23.3%,P<0.02) or abnormal ECHO alone (30%,P<0.01) as diagnostic criteria for MVP. Frequency of MVP was even more increased in patients with a thin, flat chest compared with patients with normal physical appearance (P<0.007). These findings are in support of the concept that the increased frequency of MVP in neuromuscular disorders is likely due to geometrical changes of the heart caused by thorax deformities, rather than structural changes of the mitral valve. For this reason, MVP in MyD probably belongs to the entity of so‐called benign, secondary MVP. This is further supported by the absence of symptoms of “systemic” complications of MVP in our patient

ISSN:0148-639X    

DOI:10.1002/mus.880080804

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

年代:1985

数据来源: WILEY

摘要:

AbstractWe have analyzed the effect of 6‐propylthiouracil‐induced hypothyroidism on neonatal fiber type differentiation in the rat soleus muscle. Body weight, total soleus fiber number, histochemical fiber type differentiation, and morphometry were determined at 7, 14, 21, and 28 days. Neonatal hypothyroidism (1) inhibits the apparent ∼50% increase in soleus muscle fiber number occurring at 14–21 days, (2) blocks the transformation of type 2C to type 2A fibers occurring between 14 and 21 days, (3) preferentially inhibits the increase in type 2 fiber diameter, and (4) retards the development of sarcoplasmic reticulum. Immature muscle fibers reveal type 1 and type 2 fiber myosin adenosine triphosphatase (ATPase) differentiation at pH 10.3, which drops to pH 9.4 with maturation. No myosin ATPase differentiation was found at pH 9.4 in the hypothyroid animals, even at

ISSN:0148-639X    

DOI:10.1002/mus.880080805

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

年代:1985

数据来源: WILEY

摘要:

AbstractRespiratory distress from diaphragmatic and intercostal muscular weakness was the presenting feature of two neonates with progressive spinal muscular atrophy, leading to death in the first 2 months of life. This atypical feature provides evidence of heterogeneity within the commonly used clarification of type 1 spinal muscular atrophy.

ISSN:0148-639X    

DOI:10.1002/mus.880080806

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

年代:1985

数据来源: WILEY

摘要:

AbstractWe developed two modified methods for the preparation of cryostat sections of skeletal muscle: one using solid carbon dioxide and the other using the ultra‐low freezer to prepare 2‐methylbutane (isopentane) for freezing of skeletal muscle. The results were quite satisfactory, with good preservation of cellular details and histochemical properties. Freezing artifacts were minimal when compared with the standard liquid nitrogen met

ISSN:0148-639X    

DOI:10.1002/mus.880080807

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

年代:1985

数据来源: WILEY

摘要:

AbstractElectron microscopy of intramuscular nerves in biopsy material from a child with glycogenosis type III showed massive glycogen accumulation in the Schwann cells of unmyelinated nerve fibers. Other cells, including Schwann cells of myelinated fibers, perineurial cells, endoneurial fibroblasts, endothelial cells, and pericytes, were not similarly affected.

ISSN:0148-639X    

DOI:10.1002/mus.880080808

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

年代:1985

数据来源: WILEY

摘要:

AbstractIn a reported patient with myopathic carnitine deficiency, addition of exogenous carnitine to muscle homogenates failed to correct palmitate oxidation, and oral carnitine was of no clinical benefit.27In a muscle biopsy from this patient, we found that, in contrast to the marked deficiency of free carnitine (3% of normal) short‐ and medium‐chain acylcarnitines were in the normal range and long‐chain acylcarnitine was increased almost four times. As this result confirmed the hypothesis of a muscle defect of mitochondrial oxidation of palmitate, all eight enzymes of beta‐oxidation were measured spectrophotometrically in the muscle extract. None of them was found to be defective. These data suggest that the underlying biochemical abnormality in this patient may be a deficiency of the carnitine–acylcarnitine translocase system or a defective interaction between acyl‐CoA dehydrogenase and its flavoprote

ISSN:0148-639X    

DOI:10.1002/mus.880080809

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

年代:1985

数据来源: WILEY

摘要:

AbstractIn this review, the present knowledge about the mechanisms involved in the control of the phenotypic expression of mammalian muscle fibers is summarized. There is a discussion as to how the activity imposed on the muscle fibers by the motoneuron finally induces in the muscle cells the expression of those genes that define its particular phenotype. The functional and molecular heterogeneity of skeletal muscle is thus defined by the existence of motor units with varied function, while the homogeneity of muscle fibers belonging to the same motor unit is yet another indication of the importance of activity in the control of gene expression of the mammalian muscle fiber.

ISSN:0148-639X    

DOI:10.1002/mus.880080810

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

年代:1985

数据来源: WILEY

摘要:

AbstractF‐waves were determined in the peroneal nerves of 17 normal subjects, 11 amyotrophic lateral sclerosis (ALS) patients, and 13 patients with other disorders causing neurogenic atrophy (NA) in extensor digitorum brevis muscle. F‐waves were examined with regard to latency and waveform. Latency was increased above normal for both ALS and NA patients (P<0.024 andP<0.003, respectively). In normal subjects, the mean number of repeated responses (same latency and waveform) was 1.9 (r= 1.0–5.0), where 1.0 corresponds to no repeated response. In ALS patients, repeated responses were 2.9 (r= 1.2–7.8), which is not significantly different from normal (P<0.099). In NA patients, repeated responses were 6.5 (r= 1.6–23), which is significantly above normal (P<0.041). A dominant waveform occurred in 21.5% (mean) of responses in normal subjects (r= 4%–58%). In ALS and NA, corresponding values were 40.3% (r= 10%–88%) and 44.1% (r= 17%–100%), both of which were significantly above normal (P<0.014 andP<0.012, respectively). The distribution of F‐wave latencies is often nonrandom in normal, ALS, and NA subjects. The dominant F‐wave that was present in normal subjects and significantly increased in ALS and NA subjects may result from decreased numbers of motoneurons capable of contributing to the F‐response and would seem to be a useful additional m

ISSN:0148-639X    

DOI:10.1002/mus.880080811

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

年代:1985

数据来源: WILEY