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

A 42-year-old woman had a 10-year history of external ophthalmoplegia, malabsorption resulting in chronic malnutrition, muscle atrophy and polyneuropathy. Computer tomography revealed hypodensity of her cerebral white matter. A metabolic disturbance consisted of lactic acidosis after moderate glucose loads with increased excretion of hydroxybutyric and fumaric acids. Post-mortem studies revealed gastrointestinal scleroderma as the morphological manifestation of her malabsorption syndrome, ocular and skeletal myopathy with ragged red fibers, peripheral neuropathy, vascular abnormalities of meningeal and peripheral nerve vessels. Biochemical examination of the liver and muscle tissues revealed a partial defect of cytochrome-c-oxidase (complex IV of the respiratory chain). This mitochondrial multisystem disorder may represent a separate entity to be classified between the spectrum of myoencephalopathies and oculo-gastrointestinal muscular dystrophy.
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PMID:Myo-, neuro-, gastrointestinal encephalopathy (MNGIE syndrome) due to partial deficiency of cytochrome-c-oxidase. A new mitochondrial multisystem disorder. 282 22

While deficient exercise performance of sick children results from hypoactivity and detraining, it can also be caused by specific pathophysiological factors. These can affect one or more components of physical fitness. A low maximal aerobic power will result from a low maximal stroke volume, as in aortic stenosis or cardiomyopathy; a low maximal heart rate, as in congenital complete heart block or intake of beta-blockers; a low O2 content of the arterial blood, as in anemia or advanced cystic fibrosis; and a high O2 content of mixed-venous blood, as in muscle atrophy or severe malnutrition. A high O2 cost of locomotion, as in advanced obesity or cerebral palsy, will cause the patient to exert at a high percentage of his maximal aerobic power and thus fatigue easily. A subnormal muscle strength, as in progressive muscular dystrophy or juvenile rheumatoid arthritis, is sometimes the primary factor that limits the walking ability or other daily functions. Recent data suggest that local muscle endurance, as assessed by the Wingate anaerobic test, is particularly deficient in some neuromuscular diseases. Examples are muscular dystrophies and spastic cerebral palsy. The ratio of peak anaerobic power to peak aerobic power seems lower in such patients than in able-bodied controls.
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PMID:Pathophysiological factors which limit the exercise capacity of the sick child. 372 7

The author reports on four patients (one male, three females) from the same kindred with a newly recognized autosomal recessive condition involving striated and smooth muscle that has been designated oculogastrointestinal muscular dystrophy. It is characterized by ptosis, ophthalmoplegia, and progressive intestinal pseudo-obstruction leading to malnutrition and death before 30 y. Autopsy studies in two cases showed a severe primary myopathy of smooth muscles of the stomach and intestine with intact myenteric plexus and vagus nerves. The proposita notably had myopathic changes of striated muscles but also involvement of the peripheral nerves and central nervous system characterized by demyelinating and axonal neuropathy and focal spongiform degeneration of the posterior columns.
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PMID:Oculogastrointestinal muscular dystrophy. 685 10

Dystrophin is associated with several novel sarcolemmal proteins, including a laminin-binding extracellular glycoprotein of 156 kD (alpha-dystroglycan) and a transmembrane glycoprotein of 50 kD (adhalin). Deficiency of adhalin characterizes a severe autosomal recessive muscular dystrophy prevalent in Arabs. Here we report for the first time two mongoloid (Japanese) patients with autosomal recessive muscular dystrophy deficient in adhalin. Interestingly, adhalin was not completely absent and was faintly detectable in a patchy distribution along the sarcolemma in our patients. Although the M and B2 subunits of laminin were preserved, the B1 subunit was greatly reduced in the basal lamina surrounding muscle fibers. Our results raise a possibility that the deficiency of adhalin may be associated with the disturbance of sarcolemma-extracellular matrix interaction leading to sarcolemmal instability.
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PMID:Abnormal expression of laminin suggests disturbance of sarcolemma-extracellular matrix interaction in Japanese patients with autosomal recessive muscular dystrophy deficient in adhalin. 804 Mar 15

Malnutrition is a serious threat to patients with neuromuscular disease and marginally-compensated respiratory muscle weakness. It causes atrophy of inspiratory muscles, further weakening them. It reduces respiratory drive, potentially aggravating respiratory failure, either directly or indirectly, by promoting atelectasis and pneumonia, and it contributes strongly to such patients' risk of infection, their most common cause of death. In treating such patients, it must be remembered that abrupt increases in nutritional support, particularly with high percentages of carbohydrates, will increase CO2 production, potentially worsening ventilatory failure. Certain selected neuromuscular disease patients benefit from specific nutritional treatments (carnitine for carnitine deficient patients, high-calorie diets for muscular dystrophy and acid-maltase deficiency). Finally, the amino acid, fat, and nucleic acid content of the diet affects the immune response in beneficial or harmful ways, that are just now being elucidate. The potential for useful nutritional interventions in patients with neuromuscular diseases has never looked better, but is not yet fully realized. The challenges for the future will be to work out the beneficial and harmful effects of the various nutrients in the various diseases, to find ways to rapidly identify patients who will benefit, and to determine the safest, least uncomfortable, and most effective methods of delivery of the required nutrients.
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PMID:Nutritional factors in the pathogenesis and therapy of respiratory insufficiency in neuromuscular diseases. 825 75

During the past year significant progress has been made in understanding how dystrophin deficiency leads to muscle cell necrosis in Duchenne muscular dystrophy and Becker muscular dystrophy. Dystrophin interacts with a glycoprotein complex spanning the muscle sarcolemma, effectively linking the actin cytoskeleton to the extracellular matrix. The carboxyl terminus of dystrophin is required for glycoprotein binding. Interestingly, at least three mRNAs transcribed from the distal end of the DMD gene in tissues other than muscle have been shown to encode this domain. Deficiency of a second component of the dystrophin-associated glycoprotein complex has been shown to occur in another muscle-wasting disorder, severe childhood autosomal recessive muscular dystrophy. Sequence analysis of the entire cDNA for the autosomal dystrophin-related protein utrophin has shown that dystrophin and utrophin are closely related. Furthermore, both of these proteins have been shown to bind to the same or a similar glycoprotein complex in muscle.
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PMID:Dystrophin and related proteins. 835 25

Merosin, also called laminin-2, is an isoform of laminin comprised of the alpha 2, beta 1 and gamma 1 chains. Deficiency of merosin alpha 2 chain was recently identified as the primary cause of the classical form of congenital muscular dystrophy (CMD), an autosomal recessive neuromuscular disorder characterised by muscular dystrophy and brain white matter abnormalities. Interestingly, merosin-deficient CMD and its animal model dy mouse are also accompanied by dysmyelination of peripheral motor nerves. In peripheral nerve, merosin is expressed in the endoneurium surrounding the Schwann cell/myelin sheath, while the putative merosin receptors dystroglycan and alpha 6 beta 4 integrin are expressed in the outer membrane of Schwann cell/myelin sheath. Together with the well known fact that the deposition of laminin in the basement membrane is essential for Schwann cell myelination, these findings indicate that the interaction of merosin with dystroglycan and/or alpha 6 beta 4 integrin plays an important role in peripheral myelinogenesis and that the disturbance of this interaction leads to peripheral dysmyelination in merosin deficiency. The clinical significance of peripheral dysmyelination in merosin deficiency is also discussed.
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PMID:Peripheral nerve involvement in merosin-deficient congenital muscular dystrophy and dy mouse. 913 44

The dystrophin-based membrane cytoskeleton of muscle fibers has emerged as a critical multi-protein complex which seems to impart structural integrity on the muscle fiber plasma membrane. Deficiency of dystrophin causes the most common types of muscular dystrophy, Duchenne and Becker muscular dystrophies. Muscular dystrophy patients showing normal dystrophin protein and gene analysis are generally isolated cases with a presumed autosomal recessive inheritance pattern (limb-girdle muscular dystrophy). Recently, linkage and candidate gene analyses have shown that some cases of limb-girdle muscular dystrophy can be caused by deficiency of other components of the dystrophin membrane cytoskeleton. The most recently identified component, delta-sarcoglycan, has been found to show mutations in a series of Brazilian muscular dystrophy patients. All patients were homozygous for a protein-truncating carboxy-terminal mutation, and showed a deficiency of the four sarcoglycan proteins. To determine if delta-sarcoglycan deficiency occurred in other world populations, to identify the range of mutations and clinical phenotypes, and to test for the biochemical consequences of delta-sarcoglycan gene mutations, we studied Duchenne-like and limb-girdle muscular dystrophy patients who we had previously shown not to exhibit gene mutations of dystrophin, alpha-, beta-, or gamma-sarcoglycan for delta-sarcoglycan mutations (n = 54). We identified two American patients with novel nonsense mutations of delta-sarcoglycan (W30X, R165X). One was apparently homozygous, and we show likely consanguinity through homozygosity for 13 microsatellite loci covering a 38 cM region of chromosome 5. The second was heterozygous. Both were girls who showed clinical symptoms consistent with Duchenne muscular dystrophy in males. Our data shows that delta-sarcoglycan deficiency occurs in other world populations, and that most or all patients show a deficiency of the entire sarcoglycan complex, adding support to the hypothesis that these proteins function as a tetrameric unit.
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PMID:Mutations in the delta-sarcoglycan gene are a rare cause of autosomal recessive limb-girdle muscular dystrophy (LGMD2). 1073 75

There are currently 27 national hospitals with the wards for progressive muscular dystrophy (PMD) in Japan. Today, most patients in these wards are severely motor handicapped and complicated with respiratory and/or cardiac failure. Malnutrition, dysphagia, insufficient respiratory tract clearance are common problems that cause fragility to infection. Although progress in the treatment of infection have remarkably prolonged their life-span, frequent use of antibiotics is a major factor for occurrence of drug resistant bacteria. Since we had the first case of methicillin resistant Staphylococcus aureus (MRSA) infection in 1994 in our hospital, the number of MRSA carriers increased year by year. To prevent the spread of MRSA, we revised our infection precaution manual and surveyed its consequence. We encouraged handwashing of staffs, introduced green tea in cleansing genital region and abolished the use of a private room except a patient with severe seborrheic eczema. The revision of the manual resulted in decrease of MRSA carriers. The surveillance revealed that many patients had MRSA in genital regions, although there were no relationships between colonization of MRSA and severlity of disability or complications. It was strongly suggested that toilettary care by the hands of nursing staffs was a major factor of transferring MRSA. Our study revealed that encouragement of handwashing is more powerful in preventing the spreading MRSA, and more favorable for quality of lives of PMD patients than isolating the patients.
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PMID:[MRSA infection control in the wards for progressive muscular dystrophy: the effects of encouraged handwashing]. 1082 93

Deficiency of delta-sarcoglycan (delta-SG), a component of the dystrophin-glycoprotein complex, causes cardiomyopathy and skeletal muscle dystrophy in Bio14.6 hamsters. Using cultured myotubes prepared from skeletal muscle of normal and Bio14.6 hamsters (J2N-k strain), we investigated the possibility that the delta-SG deficiency may lead to alterations in ionic conductances, which may ultimately lead to myocyte damage. In cell-attached patches (with Ba(2+) as the charge carrier), an approximately 20-pS channel was observed in both control and Bio14.6 myotubes. This channel is also permeable to K(+) and Na(+) but not to Cl(-). Channel activity was increased by pressure-induced stretch and was reduced by GdCl(3) (>5 microM). The basal open probability of this channel was fourfold higher in Bio14.6 myotubes, with longer open and shorter closed times. This was mimicked by depolymerization of the actin cytoskeleton. In intact Bio14.6 myotubes, the unidirectional basal Ca(2+) influx was enhanced compared with control. This Ca(2+) influx was sensitive to GdCl(3), signifying that stretch-activated cation channels may have been responsible for Ca(2+) influx in Bio14.6 hamster myotubes. These results suggest a possible mechanism by which cell damage might occur in this animal model of muscular dystrophy.
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PMID:Stretch-activated cation channels in skeletal muscle myotubes from sarcoglycan-deficient hamsters. 1144 68


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