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

Skeletal muscles from four infants with a severe neonatal form of myotonic muscular dystrophy showed histopathologic features of immaturity. Three of the infants died in the neonatal period and were studied at autopsy; one of these and the still-living infant had a gastrocnemius muscle biopsy. The most severely involved muscles were those associated with arthrogrypotic joints regardless of function as flexors or extensors. Pharyngeal muscles and the diaphragm were also severely involved. Immature features included irregularly distributed small, round muscles fibers with large vesicular internal nuclei and sparse myofibrils. Histochemical differentiation was incomplete and fiber types often could not be distinguished. Muscle fiber degeneration and other features of myotonic dystrophy in adult muscle were lacking. Electron microscopy showed fine granular chromatin and convoluted nuclear membranes of centronuclear fibers, dialated transvers tubules that were aligned longitudinally as in fetal myotubes, poorly formed Z-bands, simple mitochondria, and many satellite cells. We suggest that these features represent an arrest in fetal muscle maturation due to unresponsiveness of an abnormal sarcolemma to trophic influences of normal innervation.
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PMID:Maturational arrest of fetal muscle in neonatal myotonic dystrophy. A pathologic study of four cases. 13 14

Seventy-two human figure drawings by forty-three patients who had a diagnosis of Duchenne's muscular dystrophy were examined. The study includes a description of these human figure drawings according to eleven emotional indicators and according to directionality quadrants. When the human figure drawings were used as a projective tool, four personality traits of some of the children were identified: physical inadequacy, immaturity, body anxiety, and insecurity. Both the emotional indicators and the quadrant in which the figures appeared were examined in relation to stages of the disease process to see if the human figure drawings of the children might reflect more stress and anxiety at a particular stage of the disease. Suggestions for improvements and recommendations for future study are given.
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PMID:Human figure drawings by children with Duchenne's muscular dystrophy. 110 54

The leg muscle EMG responses following perturbations during stance and gait were analysed in children between 1 and 8 years of age in order to study the development of those reflex systems responsible for the compensatory movements necessary to maintain body equilibrium. Single monosynaptic reflex potentials followed by a long-lasting (about 500 msec) polysynaptic gastrocnemius EMG response, along with coactivation of all antagonistic leg muscles, were characteristic of the EMG reactions following a treadmill acceleration impulse in early infancy. From 4 years of age on, the monosynaptic reflex potentials disappeared when perturbations were induced during gait. In addition, the polysynaptic reflex response became shorter (about 100 msec) and a reciprocal mode of leg muscle activation occurred, with a consequently more rapid and effective compensation of perturbation impulses. In older children with a disorder of the motor system acquired at an early age, a partial persistence of the immature motor responses could be observed, irrespective of whether the impairment was a cerebral lesion or a muscular dystrophy. It is concluded that the coactivation pattern is due to the immaturity of those nervous structures mediating afferent information necessary for the control of bipedal stance and gait. Furthermore, the existence of mutual inhibition of monosynaptic and polysynaptic spinal reflex responses, dependent on the function of supraspinal motor centres, can be assumed.
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PMID:Stance and gait perturbations in children: developmental aspects of compensatory mechanisms. 241 91

Muscle biopsies of 5 patients with congenital muscular dystrophy (CMD) (8 months to 3 years old) were examined by electron microscopy to determine ultrastructural abnormalities of the muscle as well as of the connective tissue cells. Two populations of muscle fibers were observed in each biopsy. Besides muscle fibers with normal or enlarged diameters there were frequently very small muscle cells indicating immaturity. The most interesting findings in each biopsy were myofibroblast-like cells exhibiting active protein synthesis. Large amounts of collagen fibrils with abnormal diameters as well as accumulation of elastic fibrils within the endomysium in CMD suggest abnormalities in collagen synthesis.
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PMID:Congenital muscular dystrophy (CMD) - a collagen formative disease? 720 42

The expression of laminin subunits M, A, B1 and B2 was studied immunocytochemically in 25 cases of classical congenital muscular dystrophy (CMD), 11 hypotonic infants, 20 cases of a variety of inherited and acquired neuromuscular disorders, and 11 controls. Merosin, as indicated by labelling for the M chain, was deficient in 12 (48%) of the cases of classical CMD. Seven cases had no detectable labelling for the M chain whereas five showed traces, including three cousins from the same family. This suggests that very low expression may relate to a possible difference in the molecular defect, compared with cases completely devoid of the M chain. The A chain was abundant in regenerating fibres and in immature fibres expressing fetal myosin. In all merosin-deficient cases the A chain was over-expressed but this was not due to immaturity. A secondary reduction in sarcolemmal expression of the B1 chain occurred in five merosin-deficient cases, whilst expression in vascular tissue was normal. B1 was also reduced in one merosin-positive case of CMD, suggesting that other subunits may be involved in other forms of CMD. No differences in the expression of the B2 chain were observed in any of the cases studied. No abnormality in laminin subunits was found in controls or other neuromuscular disorders.
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PMID:Expression of laminin subunits in congenital muscular dystrophy. 758 Feb 44

Using immunohistochemical methods, we assessed the distribution of all 10 known laminin chains (alpha1-5, beta1-3, gamma1 and gamma2) in skeletal muscles from patients with Duchenne, congenital, limb girdle, or Emery-Dreifuss muscular dystrophies. The alpha2, beta1 and gamma1 chains were abundant in the basal lamina surrounding muscle fibers in normal controls; alpha1, alpha3-alpha5, beta3, and gamma2 were undetectable; and beta2 was present at a low level. Compared to controls, levels of the alpha5 chain were increased in muscles from many dystrophic patients; levels of beta1 were reduced and/or levels of beta2 were increased in a minority. However, these changes were neither specific for, nor consistent within, diagnostic categories. In contrast, levels of alpha4 were increased in muscles from all patients with alpha2 laminin (merosin)-deficient congenital muscular dystrophy. Loss of alpha2 laminin in congenital dystrophy is disease-specific but some other changes in laminin isoform expression in dystrophic muscles could be secondary consequences of myopathy, denervation, regeneration or immaturity. To distinguish among these possibilities, we compared the laminins of embryonic, denervated, regenerating, and mutant mouse muscles with those in normal adult muscle. Embryonic muscle basal lamina contained alpha4 and alpha5 along with alpha2, and regenerating muscle re-expressed alpha5 but not alpha4. Levels of alpha5 but not alpha4 were increased in dystrophin (mdx) mutants and in dystrophin/utrophin double mutants (mdx:utrn -/-), models for Duchenne dystrophy. In contrast, laminin alpha4 was upregulated more than alpha5 in muscles of laminin alpha2 mutant mice (dy/dy; a model for alpha2-deficient congenital dystrophy). Based on these results, we hypothesize that the expression of alpha5 in many dystrophies reflects the regenerative process, whereas the selective expression of alpha4 in alpha2-deficient muscle is a specific compensatory response to loss of alpha2.
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PMID:Distribution of ten laminin chains in dystrophic and regenerating muscles. 1054 49

Golden retriever muscular dystrophy (GRMD), a degenerative myopathy due to the absence of dystrophin, is genetically homologous to human Duchenne muscular dystrophy (DMD). Spontaneous death of GRMD neonates within the first 2 weeks of life occurs frequently. This report describes the microscopical muscle lesions that developed in 12 GRMD puppies aged 1-8 days of age, and makes a comparison with three normal age-matched siblings and two older GRMD dogs. Immunohistochemical methods were used to confirm dystrophin deficiency in GRMD puppies. Muscle lesions were assessed on sections stained with haematoxylin-eosin-saffron, Gomori's trichrome and alizarin red S, and their severity was graded semi-quantitatively. Muscle fibre types were determined immunohistochemically on the basis of the pattern of expression of developmental, slow and fast isoforms of myosin. Muscle lesions in the GRMD puppies were characterized by massive necrosis, affecting most muscles of the proximal limbs, trunk and neck at birth. Lingual lesions began to develop in utero, and respiratory muscles underwent terminal diffuse necrosis resulting in death from acute respiratory failure. However, GRMD puppies do not invariably die in the neonatal period. Muscle in 2-month-old GRMD dogs showed signs of regeneration (immunohistochemical immaturity of muscle tissue), which suggested that all GRMD dogs suffer from massive post-natal myonecrosis, whether fatal or not. Muscle lesions in neonates consisted mainly of hyalinization, hypertrophy, calcification and necrosis, followed by regeneration. Such "phase I" lesions due to the absence of dystrophin are found in all species in which dystrophin deficiency has been described (human beings, dogs, cats and mice), whereas the endomysial fibrosis and myofibre atrophy found in 2-month-old GRMD dogs constituted "phase II" lesions, which are specific to GRMD and human DMD.
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PMID:Muscle lesions associated with dystrophin deficiency in neonatal golden retriever puppies. 1194 98

A 2-year-old, male Weimaraner with muscular dystrophy was presented with generalized muscle atrophy of the limbs; hypertrophy of the neck, infraspinatus, and lingual muscles; dysphagia; and regurgitation. Unilateral cryptorchidism, unilateral renal agenesis, and hiatal hernia were also detected. Spontaneous muscle activity was identified on myography. Serum creatine kinase was markedly elevated. Immunohistochemical staining for dystrophin was restricted to suspected revertant (characteristics of immaturity) fibers. Histologically, skeletal myofiber degeneration, endomysial fibrosis, and mineralization were present. Following euthanasia, necropsy revealed hypertrophy of the diaphragm and cardiac muscle fibrosis. This case of muscular dystrophy represents a slowly progressive form with organ agenesis.
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PMID:Dystrophin-deficient muscular dystrophy in a Weimaraner. 1761 4