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Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Effects of voluntary wheel running on contractile properties of diaphragm (DIA) and soleus (SOL) of dystrophic (mdx) and control (C57BL/10SNJ) mice were evaluated. In particular, we tested the hypothesis that daily voluntary running is not deleterious to muscle function in mdx mice. Both groups of mice ran extensively (control mice approximately 7 km/day, mdx mice approximately 5 km/day). Exercise increased maximal specific tetanus tension of mdx DIA from 1.02 +/- 0.04 to 1.33 +/- 0.06 kg/cm2 but did not restore it to the control level (2.55 +/- 0.17 kg/cm2). Maximal tetanus tension of sedentary mdx SOL (2.41 +/- 0.17 kg/cm2) was reduced compared with control (3.10 +/- 0.15 kg/cm2) and was not altered by running activity. Optimal length was significantly lower in DIA of mdx mice, and exercise did not change this. Fatigability and contractile properties of muscles measured in vitro were not altered by running activity with the exception of increased contraction time in mdx DIA. In conclusion, extensive wheel running is not deleterious to muscle function in mdx mice contrary to predictions of the "work overload" theory of muscular dystrophy. Rather, this exercise is beneficial for active tension generation of mdx DIA, the muscle most closely resembling muscles of patients with Duchenne muscular dystrophy.
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PMID:Voluntary exercise decreases progression of muscular dystrophy in diaphragm of mdx mice. 783 93

The effects of exercise and the combination of exercise and clenbuterol on progression of muscular dystrophy were studied in mdx mice. At 3 wk of age, mdx mice were randomly assigned to sedentary (MS), exercise (ME), or combined exercise and clenbuterol (MEC) groups. Clenbuterol was given in the drinking water (1.0-1.5 mg . kg body weight-1 . day-1), and exercise consisted of spontaneous running activity on exercise wheels. At 3 mo or 1 yr of age, ventilatory function, contractile properties, and morphological characteristics of the soleus (Sol) and diaphragm (Dia) muscles were measured. The mdx mice receiving clenbuterol ran less than the mice without clenbuterol. The combination of clenbuterol and exercise was associated with an increase in Sol muscle weight and a muscle weight-to-body weight ratio of 30-35% compared with the sedentary group and approximately 20% compared to exercise alone. Myosin and total protein concentrations of the Sol and Dia increased in the MEC group at 1 yr of age only. Normalized active tension was increased in the Dia at 1 yr of age in both the ME and MEC groups by approximately 30%. Absolute tetanic tension of the Sol was increased at both 3 mo and 1 yr of age in the MEC compared with the MS group. At 1 yr of age, there was an additional 23% increase compared with the ME group. Fatigability increased in the MEC group by approximately 25% in the Sol and Dia muscles at both ages compared with the MS and ME groups. Results indicate that exercise and exercise plus clenbuterol decrease the progression of muscular dystrophy. However, different mechanisms may be involved because the combination of clenbuterol and exercise resulted in increased fatigability and the development of deformities, whereas exercise alone did not. Therefore, clenbuterol may not be suitable for use in patients with muscular dystrophy.
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PMID:Exercise and clenbuterol as strategies to decrease the progression of muscular dystrophy in mdx mice. 896 30

The Congenital Myasthenic Syndromes (CMS), a group of heterogeneous genetic disorders of neuromuscular transmission, are often misdiagnosed as congenital muscular dystrophy (CMD) or myopathies and present particular management problems. We present our experience of 46 children with CMS, referred to us between 1992-2007 with provisional diagnoses of congenital myopathy (22/46), CMS or limb-girdle myasthenia (9/46), central hypotonia or neurometabolic disease (5/46), myasthenia gravis (4/46), limb-girdle or congenital muscular dystrophy (4/46) and SMA (2/46). Diagnosis was often considerably delayed (up to 18y4 m), despite the early symptoms in most cases. Diagnostic clues in the neonates were feeding difficulties (29/46), hypotonia with or without limb weakness (21/46), ptosis (19/46), respiratory insufficiency (12/46), contractures (4/46) and stridor (6/46). Twenty-five children had delayed motor milestones. Fatigability developed in 43 and a variable degree of ptosis was eventually present in 40. Over the period of the study, the mainstay of EMG diagnosis evolved from repetitive nerve stimulation to stimulation single fibre EMG. The patients were studied by several different operators. 66 EMGs were performed in 40 children, 29 showed a neuromuscular junction abnormality, 7 were myopathic, 2 had possible neurogenic changes and 28 were normal or inconclusive. A repetitive CMAP was detected in only one of seven children with a COLQ mutation and neither of the two children with Slow Channel Syndrome mutations. Mutations have been identified so far in 32/46 children: 10 RAPSN, 7 COLQ, 6 CHRNE, 7 DOK7, 1 CHRNA1 and 1 CHAT. 24 of 25 muscle biopsies showed myopathic changes with fibre size variation; 14 had type-1 fibre predominance. Three cases showed small type-1 fibres resembling fibre type disproportion, and four showed core-like lesions. No specific myopathic features were associated with any of the genes. Twenty children responded to Pyridostigmine treatment alone, 11 to Pyridostigmine with either 3, 4 DAP or Ephedrine and five to Ephedrine alone. Twenty one children required acute or chronic respiratory support, with tracheostomy in 4 and nocturnal or emergency non-invasive ventilation in 9. Eight children had gastrostomy. Another 11 were underweight for height indicative of failure to thrive and required dietetic input. A high index of clinical suspicion, repeat EMG by an experienced electromyographer and, if necessary, a therapeutic trial of Pyridostigmine facilitates the diagnosis of CMS with subsequent molecular genetic confirmation. This guides rational therapy and multidisciplinary management, which may be crucial for survival, particularly in pedigrees where previous deaths have occurred in infancy.
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PMID:Congenital myasthenic syndromes in childhood: diagnostic and management challenges. 1870 67