摘要:

AbstractFour corticosteroid hormones were administered (5 mg/kg/day) to rats over 6 to 10 days. Both biochemical and microscopic techniques were employed to determine the influence of these corticosteroids on the fine structure and growth of five striated muscles. Throughout, dexamethasone and triamcinalone were more potent than prednisone or cortisone in influencing muscle growth. The corticosteroids' action on the heart was anabolic, increasing its RNA and protein content. In contrast, the same corticosteroids were catabolic against fast‐twitch muscles (e.g., extensor digitorum longus), inducing appreciable atrophy. However, slow‐twitch muscles (e.g., soleus) were more resistant to these hormones, exhibiting an intermediate response between that of the heart and fast‐twitch muscles. Only minor morphological changes were found in both fast and slow muscles 10 days after the corticosteroid treatments. The hormones′ atrophic effects on skeletal muscle primarily arose from the corticosteroid's ability to inhibit protein synthesis, via decreases in the muscles′ ribosomal capacities. Whole‐body protein synthesis was also suppressed by these corticosteroids, but to a lesser extent than in the whole skeletal

ISSN:0148-639X    

DOI:10.1002/mus.880090102

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

年代:1986

数据来源: WILEY

摘要:

AbstractA kinetic bioluminescence assay with optimized reagent conditions has been developed for application as a screening test for increased creatine kinase (CK) activities in dried blood spots. This test is used for the early detection of Duchenne muscular dystrophy (DMD) in a voluntary CK screening program in West Germany of the 176,600 boys tested up to December 31, 1984, 48 who were less than 6 months old had certain or probable DMD (frequency 1: 3679). In 1983 and 1984, the rate of false positive results was 0.016% for a cut‐off activity 300 U/liter and 0.061% for a cut‐off activity 180 U/liter. Long‐term counseling is offered to families of newly detected DMD patients in order to facilitate the aims of the screening program, namely, avoidance of secondary cases in affected families, early professional care for the sick child, and the early opportunity to make the appropriate decisions for a life with an handicapped child. Two types of a benign hereditary blood anomaly were also detected by CK screening (CK‐BB inside erythrocytes or thromb

ISSN:0148-639X    

DOI:10.1002/mus.880090103

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe present study was undertaken to establish normal values of theNτ‐methylhistidine to creatinine excretion ratio in very premature infants, to observe changes with postnatal age, and to determine whether or not reliable data on this index of myofibrillar protein breakdown could be obtained from untimed urine samples without recourse to the 24‐ hour collections used previously. The normal range (95% confidence limits) of the molar excretion ratio for unstressed infants was established to be between 0.0248 and 0.0440. Narrower limits of variability occurred when nutrient intake was controlled at a satisfactory level or when comparisons were between sequential urine samples from single infants. No diurnal changes could be detected. We conclude that analyses ofNτ‐methylhistidine and creatinine on spot urine samples permit the calculation of an excretion ratio that is reproducible both within and between individual infants and that should be useful in assessing changes in myofibrillar protein breakdown caused by differences in clinical, pharmacologic, or nutritional

ISSN:0148-639X    

DOI:10.1002/mus.880090104

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe proportions of different fiber types (type 1 and type 2) on the borders of fascicles are shown to differ from the proportions internally. This finding is based on the analysis of a total of 245 fascicles from whole cross‐sections of the vastus lateralis muscle from 13 men, aged from 26–80 years. Generally, the difference is more marked in the young than in the old. It is argued that the causes of this difference are likely to be local factors in the mus

ISSN:0148-639X    

DOI:10.1002/mus.880090105

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

年代:1986

数据来源: WILEY

摘要:

AbstractQuantitative electromyography (EMG) was performed in 223 infantile and juvenile cases of spinal muscular atrophy (SMA), which were classified into 3 groups: (A) form la, Werdnig‐Hoffmann disease; (B) forms lb and II, intermediate forms; and (C) form III, Kugelberg‐Welander disease. The groups differed in the occurrence of spontaneous activity; only groups A and B showed spontaneous rhythmic firing of motor units, whereas in long‐standing cases, pseudomyotonic volleys appeared. The parameters of individual motor unit potentials (MUPs) differed in the different forms of the disease. Group A showed, in addition to long potentials of high amplitude, some short and low amplitude potentials, and the histograms of amplitudes and durations were bimodal. In the long‐standing cases, the values of these parameters were shifted to longer durations and higher amplitudes of motor unit potentials. However, in long‐standing cases of the benign group C, the short, low potentials appeared as well as socalled linked potentials. In the very early stage of the disease, the children who were found to be suffering from chronic forms of SMA—both malignant (form lb and II or benign group C)—had an EMG record that was slightly different from that of acute form la. Their EMG record shows more so‐called “spinal” signs, particularly in the benign group C (Kugelberg‐Welander disease). These increasing features of chronic anterior horn cell involvement followed a pattern of reinnervation and hypertrophy of muscle fibers. These phenomena were particularly seen in the benign group C. These findings indicate that in the early stage of SMA, the EMG not only has diagnostic, but a

ISSN:0148-639X    

DOI:10.1002/mus.880090106

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

年代:1986

数据来源: WILEY

摘要:

AbstractFrog muscles bathed in solutions equilibrated with 0.5%–2.0% halothane develop large contractures when cooled to 2–4°C. These halothane‐cooling contractures (HCC) are dose dependent and reproducible; they are potentiated by lidocaine (5 mM), abolished by procaine (5‐mM), and partially inhibited by procainamide (5 mM) or sodium salicylate (2 mM). The HCC provides a simple model system for investigating the effects of low halothane concentrations on Ca homeostasis and contractility in skeleta

ISSN:0148-639X    

DOI:10.1002/mus.880090107

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

年代:1986

数据来源: WILEY

摘要:

AbstractWe report immunofluorescence observations on normal and dystrophic human muscle using an antibody (anti‐bF) raised against bovine fetal myosin and specific for fetal myosin heavy chains. In rat skeletal muscle, anti‐bF was previously found to react selectively with myosin isoforms expressed during fetal and early postnatal development and in regenerating muscles.11Anti‐bF stained most fibers in human fetal and neonatal muscle, whereas only nuclear chain fibers of muscle spindles were labeled in normal adult muscle. In muscle biopsies from patients with Duchenne's muscular dystrophy, numerous extrafusal fibers were stained: some were small regenerating fibers, others were larger fibers presumably resulting from previous regenerative events. Fetal myosin immunoreactivity in Duchenne's dystrophy appears to reflect the reexpression of fetal‐specific myosin isoforms and provides a new valuable tool for identifying regenerating fibers and following their destiny in dystrophic

ISSN:0148-639X    

DOI:10.1002/mus.880090108

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

年代:1986

数据来源: WILEY

摘要:

AbstractThis study was undertaken to determine whether the large delayed creatine kinase (CK) rise, previously only reported in normal subjects after stepping exercise, was caused by the eccentric or concentric contractions. On separate occasions, five normal subjects performed the same amount of total work by walking either up (mainly concentric contractions) or down (mainly eccentric contractions) a treadmill inclined at 13°. After uphill walking, peak plasma CK values of 60–200 IU/liter occurred 24 hours after exercise. Downhill walking resulted in peak values of 700–1500 IU/liter 4–7 days later. It is concluded that it is the eccentric contractions that are responsible for the large enzyme

ISSN:0148-639X    

DOI:10.1002/mus.880090109

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

年代:1986

数据来源: WILEY

摘要:

AbstractWe report a patient with progressive muscle weakness, areflexia, and no sensory loss. Electromyography revealed normal sensory nerve conductions, mild slowing of motor nerve conduction velocities, low amplitude compound muscle action potentials, a neuromuscular transmission defect characterized by prominent facilitation, and diffuse fibrillation potentials. Muscle biopsies showed acute denervation atrophy, and at autopsy, there was anterior horn cell loss and gliosis in the spinal cord. The findings suggest the coexistence of a motor neuropathy and a facilitating myasthenic syndrome.

ISSN:0148-639X    

DOI:10.1002/mus.880090110

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

年代:1986

数据来源: WILEY

摘要:

AbstractFrom 1 to 14 days after denervation, glucose uptake in the fast extensor digitorum longus and slow soleus muscles in rats was investigated and compared with that of the corresponding intact contralateral muscles. Denervation‐induced atrophy in soleus was greater than that in extensor digitorum longus muscle. Glucose uptake in extensor digitorum longus muscle increased significantly, but that in soleus decreased significantl

ISSN:0148-639X    

DOI:10.1002/mus.880090111

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

年代:1986

数据来源: WILEY