Three days of intermittent stretching after muscle disuse alters the proteins involved in force transmission in muscle fibers in weanling rats

The aim of this study was to determine the effects of intermittent passive manual stretching on various proteins involved in force transmission in skeletal muscle. Female Wistar weanling rats were randomly assigned to 5 groups: 2 control groups containing 21- and 30-day-old rats that received neither immobilization nor stretching, and 3 test groups that received 1) passive stretching over 3 days, 2) immobilization for 7 days and then passive stretching over 3 days, or 3) immobilization for 7 days. Maximal plantar flexion in the right hind limb was imposed, and the stretching protocol of 10 repetitions of 30 s stretches was applied. The soleus muscles were harvested and processed for HE and picrosirius staining; immunohistochemical analysis of collagen types I, III, IV, desmin, and vimentin; and immunofluorescence labeling of dystrophin and CD68. The numbers of desmin- and vimentin-positive cells were significantly decreased compared with those in the control following immobilization, regardless of whether stretching was applied (P<0.05). In addition, the semi-quantitative analysis showed that collagen type I was increased and type IV was decreased in the immobilized animals, regardless of whether the stretching protocol was applied. In conclusion, the largest changes in response to stretching were observed in muscles that had been previously immobilized, and the stretching protocol applied here did not mitigate the immobilization-induced muscle changes. Muscle disuse adversely affected several proteins involved in the transmission of forces between the intracellular and extracellular compartments. Thus, the 3-day rehabilitation period tested here did not provide sufficient time for the muscles to recover from the disuse maladaptations in animals undergoing postnatal development.

Duchenne and Becker muscular dystrophy: a molecular and immunohistochemical approach

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations in the dystrophin gene. We studied 106 patients with a diagnosis of probable DMD/BMD by analyzing 20 exons of the dystrophin gene in their blood and, in some of the cases, by immunohistochemical assays for dystrophin in muscle biopsies. In 71.7 percent of the patients, deletions were found in at least one of the exons; 68 percent of these deletions were in the hot-spot 3' region. Deletions were found in 81.5 percent of the DMD cases and in all the BMD cases. The cases without deletions, which included the only woman in the study with DMD, had dystrophin deficiency. The symptomatic female carriers had no deletions but had abnormal dystrophin distribution in the sarcolemma (discontinuous immunostains). The following diagnoses were made for the remaining cases without deletions with the aid of a muscle biopsy: spinal muscular atrophy, congenital myopathy; sarcoglycan deficiency and unclassified limb-girdle muscular dystrophy. Dystrophin analysis by immunohistochemistry continues to be the most specific method for diagnosis of DMD/BMD and should be used when no exon deletions are found in the dystrophin gene in the blood.

As distrofias musculares de Duchenne (DMD) e de Becker (DMB) são doenças causadas por mutação no gene da distrofina. Foram estudados 106 casos com a suspeita diagnóstica de DMD/BMD com a analise de 20 exons do gene da distrofina no sangue e biópsia muscular com imuno-histoquímica para distrofina em alguns casos. Em 71,7 por cento dos casos foi encontrada deleção em pelo menos um dos exons, sendo que 68 por cento das deleções localizam-se na região 3' hot spot. Foram encontradas deleções em 81,5 por cento dos DMD e em todos os BMD, sendo que os sem deleção tinham deficiência de distrofina, incluindo a mulher com DMD. As portadoras sintomáticas não tinham deleções mas anormalidades na distribuição da distrofina no sarcolema. Os outros casos sem deleção, com auxilio da biópsia muscular tiveram outros diagnósticos (atrofia muscular espinhal, miopatia congênita, deficiência de sarcoglicanos, distrofia de cinturas-membros sem classificação). A análise imuno-histoquímica para distrofina na biópsia muscular continua sendo o método mais específico para diagnóstico de DMD/DMB e deve ser utilizado quando não são encontradas deleções do gene da distrophina no sangue.

Utility of dystrophin and utrophin staining in childhood muscular dystrophy.

To determine the utility of dystrophin and utrophin staining in the differential diagnosis of childhood muscular dystrophy. Fifty muscle biopsies of histologically confirmed cases of childhood muscular dystrophy, below 16 years of age, were stained immunohistochemically for dystrophin and utrophin. All the 30 muscle biopsies of patients with Duchenne muscular dystrophy (DMD) showed all or majority of muscle fibers deficient for dystrophin and positive for utrophin. In the 4 female DMD carriers there was mosaic pattern of staining for dystrophin and reciprocal positivity for utrophin. All the muscle biopsies of patients with other childhood onset muscular dystrophies were positive for dystrophin and negative for utrophin. This study shows that dystrophin staining differentiates DMD and DMD carriers from other childhood muscular dystrophies and utrophin staining is of no added value. Utrophin up-regulation may compensate for structural deficiency in dystrophic muscle.

Deficiency of the 50 kDa dystrophin-associated-glycoprotein (adhalin) in an Indian autosomal recessive limb girdle muscular dystrophy patient : immunochemical analysis and clinical aspects.

Abnormalities of dystrophin are a common cause of muscular dystrophy and testing for dystrophin gene or protein has become a part of routine diagnostic evaluation of patients who present with progressive proximal muscle weakness, high serum creatine kinase concentrations, and histopathological evidence of a dystrophic process. Patients who have no dystrophin abnormalities are assumed to have autosomal recessive muscular dystrophy. In a family consisting of 5 sibs, 2 mentally normal brothers presented with abnormal gait and protrusion of chest and hips. Muscle biopsy from one of them showed dystrophic changes and reduced patchy binding of dystrophin. No detectable deletion was observed in the patient's DNA and his brother with cDMD probes. Dystrophin associated proteins, beta-dystroglycan showed discontinuous immunostaining in the sarcolemma and alpha-sarcoglycan (adhalin) was totally absent, while beta-, gamma-, and delta-sarcoglycans were highly reduced. Immunoblot analysis showed dystrophin of normal molecular weight but of decreased quantity, beta-dystroglycan was reduced by about 37% while alpha-sarcoglycan was completely absent. This study is a first attempt for a systematic clinical, genetic and molecular investigation of the autosomal recessive LGMD in India.

Rigid spine syndrome: case report

We describe a patient who had difficulty in walking since toddling stage and presented proximal upper and lower member weakness which have evolved to a progressive limitation of neck and trunk flexure, compatible with rigid spine syndrome. The serum muscle enzymes were somewhat elevated and the electromyography showed a myopatic change. The muscle biopsy demonstrated an active and chronic myopathy. The DNA analysis through PCR did not display any abnormality for dystrophin gene. The dystrophin by immnofluorescence was present in all fibers, but some interruptions were found in the plasma membrane giving it the appearance of a rosary. The test for merosin was normal.

Altered deposition of extracellular matrix components in the skeletal muscle and lymph node of the MDX dystrophic mouse

1. MDX mice derived from a colony of C57BL/10ScSn mice develop an X-linked recessive muscular dystrophy, thus providing an adequate to study the pathogenesis of muscular dystrophy. 2. Skeletal myofibers of MDX mutant mice were heterogenous, with disorganization of myofilaments and the absence of immunolabelling for dystrophin with monoclonal antibody DY4/6D3. 3. Marked deposition of reticulin, collagenic fiber (types I, IV) and laminin (LN) were consistently present mostly around lesioned and necrotic myofibers associated eith an intense inflammatory reaction, whereas strong immunolabelling for TIII-C, TIV-C and FN was often associated with regenerated fibers. 4. During the onset (3 weeks of postnatal life) of disease and height of myonecrosis (5-6 weeks of postnatal life), popliteal lymph nodes showed dense argyrophilic meshwork, intense immunolabeling for collagens types I and IV, FN, LN and enlargement of the hili which were packed with mononuclear cells. Such alterations, albeit less intense, were still observed in MDX mice with 20 weeks of postnatal life. 5 The results support the view that ECM components might be influencing the migration of inflammatory cells and the process of myonecrosis in the skeletal muscle of MDX dystrophic mice

Dystrophin assay in muscular dystrophies: an Indian experience.

BACKGROUND. Dystrophin, a protein situated on the plasma membrane of skeletal muscle has been found to be abnormal in quality and quantity in patients with muscular dystrophies and may be useful in distinguishing between the different types. Experience with the technique has been limited to western countries. METHODS. We used dystrophin staining with monoclonal NCL-DYS (rod domain) antidystrophin antibody using the avidin-biotin conjugate immunoperoxidase technique in 16 out of 20 patients with various types of muscular dystrophies at a large tertiary care medical centre in India. RESULTS. The technique was unsuccessful in 4 cases. In the others the dystrophin staining pattern correlated well with the clinical diagnosis in 11 out of 16 patients. In the other 5 patients dystrophin assay helped to differentiate between Duchenne muscular dystrophy and the Becker muscular dystrophy in 2 patients suspected to have limb-girdle muscular dystrophy, it differentiated Duchenne muscular dystrophy from the Emery-Dreifuss muscular dystrophy and detected a manifest female carrier with Duchenne's dystrophy. CONCLUSION. Dystrophin staining may be useful in the differential diagnosis of patients with muscular dystrophies in India.

Carrier detection of Duchenne and Becker muscular dystrophy using muscle dystrophin immunohistochemistry

Para determinar se imuno-histoquímica com distrofina poderia melhorar a detecçäo de portadoras de distrofia muscular de Duchene (DMD) e de Becker (DMB), analisamos 14 biopsias musculares de 13 portadoras prováveis ou possíveis de DMD e de uma portadora provável de DMB. Todas as mulheres foram também avaliadas usando métodos convencionais, incluindo análise genética, avaliaçäo clínica e neurológica, níveis séricos de CK, EMG e biópsia muscular com estudo histoquímico. Em 6 casos havia um mosaico de fibras musculares distrofina-positivas e distrofinas-negativas, que permitia caracterizar um estado de portadora. Comparando imuno-histoquímica com distrofina e métodos tradicionais, notou-se que este método é menos sensível que medidas de CK, mas é mais sensível que EMG e biópsia muscular. O uso deste método associado a CK, EMG e biópsia muscular aumentou a possibilidade de detecçäo de portadoras. Este método é também útil para distinguir portadoras manifestantes de DMD de pacientes com outras doenças neuromusculares como a distrofia cintura-membros e amiotrofia espinhal progressiva

Dystrophin test in differential diagnosis of childhood muscular dystrophies.

Two cases of childhood muscular dystrophy are described. One of them had clinical features suggestive of Emery-Dreifuss muscular dystrophy and the other with some features of Prader-Willi syndrome, besides proximal muscle weakness. Muscle biopsy from both cases revealed a clear abnormality of dystrophin, and were diagnosed as having Duchenne muscular dystrophy (DMD) by immunofluorescence examination; that is, absent dystrophin at the membrane of the muscle fibers. The clinical spectrum of DMD-related myopathies and the importance of dystrophin testing in childhood muscular dystrophies is discussed.

Distrofina na diferenciaçäo das distrofias de Duchenne e Becker: estudo imuno-histoquímico comparado com o estadio clínico, enzimas séricas e biópsia muscular / Dystrophin in the differentiation between Duchenne and Becker muscular dystrophies: an immunohistochemical study compared with the clinical stage, serum enzymes and muscle biopsy

Foram estudados 55 casos de distrofia muscular progressiva (34 Duchenne, 12 Duchenne com distrofina residual e 9 Becker), comparando idade, época de início e tempo de sintomas, graduaçäo na escala de Vignos e Archibald, níveis de enzimas séricas e presença de distrofina nas biópsias musculares por imunofluorescência. A intensidade dos sintomas, gravidade do quadro clínico, proliferaçäo de tecido conjuntivo endomisial e infiltraçäo por tecido adiposo estäo inversamente relacionadas à quantidade de distrofina presente nas biópsias e, diretamente, à presença de fibras hipertróficas e fibras angulares escuras atróficas. Nos comentários säo abordados alguns aspectos sobre a diferenciaçäo da distrofina muscular de Duchenne e Becker, a distrofina residual nos casos de Duchene e a importância do teste para o diagnóstico adequado