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

Erythrocyte ghost (Na+ + K+) ATPase activity was studied in mice with hereditary muscular dystrophy (strain C 57 BL 6J/dy) and appropriate controls. No difference was observed in the enzymatic activity between dystrophic and any of the healthy genotypes. Ouabain 5 mM and 0.1 mM inhibited the enzymatic activity and no difference was observed between dystrophic and control animals. The results are discussed in the light of the literature.
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PMID:Erythrocyte ghost (Na+ + K+) ATPase activity in mice with hereditary muscular dystrophy (strain C57 BL/64J/dy). 7 52

A comparative study was carried out in the properties of ATPase system of the skeletal muscle nuclei in the rabbits in norm and with experimental muscular dystrophy conditioned by E-avitaminosis. It is shown that in the system, containing 1.5 mM of MgCl2, ATPase system of the nuclei is activated by sodium and potassium ions. In norm maximum activation is observed with their presence in the medium, the concentration being 80 and 70 mM, respectively. With experimental muscular dystrophy maximum activating concentrations decrease and are equal for both cations - 30 mM. Activation of the enzymatic system by these ions is specific because the introduction of equimolar quantities of cholin-chloride or lithium, cesium ions instead of sodium ions into the incubation medium evokes no activation of the ATPase system of the rabbit skeletal muscles both in norm and with experimental muscular dystrophy. A simultaneous presence of sodium and potassium ions in optimum concentrations in the incubation medium makes for an increase of ATPase activity to the same extent as the presence of one of these cations. Oubain, a specific inhibitor of Mg2+, Na+, K+- ATPase, taken in the concentrations of 10(-4) and 10(-3) M did not decrease the intensity of ATP hydrolysis and its activation conditioned by the presence of sodium or potassium. A conclusion is made that Mg2+, Na+, K+-ATPase taking part in the work of "sodium pump" is absent in the nuclei of skeletal muscles.
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PMID:[Availability of Mg2+, Na+, and K+-ATPase in the nuclei of the skeletal muscles of rabbits normally and during experimental muscular dystrophy]. 12 69

The total ATPase activity of the rabbit skeletal muscle nuclei was established to be a sum of activities of two ATPases--Mg2+ and Mg2+, Ca2+-ATPases. The latter composes 50% of total ATPase activity for skeletal muscles nuclei of the normal rabbits and 30% for skeletal muscles nuclei of the rabbits with muscular dystrophy. Mg+, Ca2+-ATPase of the skeletal muscle nuclei is activated by calcium ions within a range of 10(-6)--10(-4) M and is inhibited with its concentration of 0.5-10(-3) M and higher. Sodium and potassium ions activate Mg2+, Ca2+-ATPase. Inhibition of Mg2+-ATPase is observed for the skeletal muscle nuclei of the rabbits in norm with the presence of 80 mM of Na+ and 70 mM of K+ in the incubation medium. Under experimental muscular dystrophy such an effect is not observed in connection with the fact that the concentration of monovalent cations in the incubation medium does not exceed 60 mM. The ATPase activity in nuclei of the rabbit skeletal muscles may be also manifested in the presence of Mn2+ greater than Ca2+ greater than Ba2+. A problem is under discussion as to substitution of ions Mg2+ by ions Mn2+, Ca2+, Ba2+ in manifestation of the Mg2+ATPase activity for the skeletal muscle nuclei of the normal rabbits and of those with experimental dystrophy.
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PMID:[Mg 2+, Ca 2+-ATPase of skeletal muscle nuclei in normal rabbits and in rabbits with experimental muscular dystrophy]. 12 61

The level of the ATPase activity in the skeletal muscles nuclei with experimental muscular dystrophy and the sensitivity to bivalent (Mg2+, Ca2+) and univalent (Na+, K+) cations under conditions of delipidation were studied. It is established that among ATPases of the young rabbit skeletal muscles nuclei there is ATPase sensitive to monovalent cations: the presence of Na+ or K+ produces a 45% increase in its activity in some experiments as compared to the initial level. This activation is attributed to Mg2+, Ca2+-ATPase the action of which is not realized in the presence of EGTA-chelator of calcium ions. A decrease in the total ATPase activity in the skeletal muscles nuclei resulted from the experimental muscular dystrophy development occurs due to a decrease in the Mg2+, Ca2+-ATPase activity as the ability for activation by the monovalent cations is practically lost under these conditions. Delipidation of the skeletal muscles nuclei, which results in their loss of some phospholipids and cholesterin, is accompanied by the ATPase activity decrease. At the same time the nuclei ATPase activity lose its ability to activate by monovalent cations: Na+, K+. A conclusion is made that during delipidation the decrease in the total ATPase activity is due to a decrease in the activity of its Mg2+, Ca2+-part.
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PMID:[Changes in the ATP-ase activity of skeletal muscle nuclei of rabbits with dystrophy and following their delipidation]. 13 32

The properties and localization of ATPase system in nuclei of skeletal muscle of normal rabbit and of those with experimental muscle dystrophy were studied by electron cytochemistry. The product of cytochemical reaction of ATP hydrolysis, which is a marker of ATPase activity localization in nuclear ultrastructures, was detected on the nuclear membrane, in chromatin and in the nucleolus, ATPase activity in the nuclei was detected in the presence of both, Mg2+ and Ca2+. Addition to the incubation medium, originally containing Mg2+, Na+ and K+, resulted in an increased formation of the product reaction in all the nuclear ultrastructures in both in the norm and under experimental muscle dystrophy. However, specific inhibitor of Mg2+, Na+, K+-ATPase--ouabain--suggests the absence in the nuclei of skeletal muscles of rabbit of transport ATPase working in the "Na-pump" system. The results of experiments with a specific complex of Ca2+--EGTA allow to suppose that Mg2+, Ca2+-ATPase of skeletal muscle nuclei of normal rabbits is localized in the nucleoplasm, whereas Mg2+-ATPase is found on the nuclear membrane. Using EGTA we failed to detected the localization of Mg2+, Ca2+-ATPase in nuclear ultrastructures upon experimental muscular dystrophy.
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PMID:[Electron-cytochemical study of the localization and properties of ATPases in the isolated nuclei of rabbit skeletal muscle under normal conditions and in experimental muscular dystrophy]. 14 28

Studies were carried out to examine oxidative phosphorylation, cation uptake, and electrokinetic properties of liver mitochondria from genetically dystrophic mice in comparison with those from livers of littermate controls. While no differences were seen with respect to the rates of substrate oxidation, ADP/oxygen ratio, and RCl and cytochrome content, the mitochondria from the dystropic group were characterized by an elevated basal ATPase activity in the presence of NaCl. Additionally, these mitochondria were highly sensitive to high concentrations of exogenously added K+ that, besides stimulating state 4 respiration, caused uncoupling in the mitochondria. These mitochondria accumulated Ca2+ at a higher rate, and unlike the controls, Ca2+ uptake was not sensitive to exogenously added K+. It was also observed that the net negative charge on mitochondria decreased significantly in the dystrophic state. It is thus apparent that muscular dystrophy manifests itself also in terms of alteration in the membrane properties of liver mitochondria.
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PMID:Energy coupling in liver mitochondria from dystrophic mice: differential sensitivity of oxidative phosphorylation and Ca2+ uptake to K+. 14 26

The purpose of this study was to determine whether the previously reported differences in adenylate cyclase activity between the sarcolemma of normal and dystrophic chick muscles are also found in the SR, to search for a possible relationship between the adenylate cyclase changes and the pathophysiology of dystrophy, and to investigate whether the findings can be extended to Duchenne human muscular dystrophy by studying the adenylate cyclase and ATPase activities of erythrocyte ghosts from DMD patients and carriers. Microsomes were separated by standard techniques from the pectoralis muscles of normal and dystrophic ckeckens of various ages. The microsomal yields were significantly larger in dystrophic muscles. Adenylate cyclase activities in dystrophic microsomes were higher than those in matched controls and increased with the progression of the disease. The ratio between the two rose from one at 2 weeks of age to nine at about 9--10 weeks. Kinetic analyses showed that the ks for MgATP2- was about 40 microM (at 3 mM Mg2+ and 0.3 mM Ca2+) both in normal and dystrophic microsomes, that calcium caused umcompetitive inhibition of the enzyme (Ki = 0.2 mM), that the effect of calcium was noncooperative (Hill coefficient, nH = 1), that calcium did not affect the cooperativity for MgATP2-, and that magnesium competitively removed the calcium inhibition and caused additional, cooperative stimulation of the enzymatic activity (ka = 1.5 mM; NH =2). The major difference between normal and dystrophic adenylate cyclase was a higher enzymatic velocity in the latter, suggesting a larger amount of enzyme. We investigated whether altered cAMP levels may effect calcium accumulation. Calcium uptake measured (in the presence of oxalate) at several ages revealed no difference between normal and dystrophic chickens. The extent of calcium binding was also similar, although the kd for Ca2+ was lower in dystrophic microsomes. Binding was enhanced in the presence of exogenous protein kinase, but the responses of normal and dystrophic tissues were similar. We concluded that the elevation of adenylate cyclase in dystrophy was not related to microsomal calcium accumultion. Ivestigation of the localization of microsomal adenylate cyclase supported this view. Separation of calcium-loaded microsomes on a discontinuous sucrose gradient into four fractions demonstrated that adenylate cyclase activity, measured in the presence of Lubrol-PX and EGTA, was inversely related to calcium-accumulating activity. Na+, K+-ATPase comigrated with adenylate cyclase. Highest specific activities were found in the lightest fraction. These observations were confirmed by histochemical studies. The reaction product from adenylate cyclase activity was present predominantly in the terminal cisternae of the SR. In the context of the literature, our findings suggest that the rises in adenylate cyclase and Na+, K+-ATPase in avian dystrophy are compensatory changes, elicited by a defect in ECC at the calcium release step...
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PMID:Adenylate cyclase in muscular dystrophy. 15 10

Avian muscular dystrophy is an autosomal recessive genetic disease characterized by early hypertrophy and loss of function of pectoralis major. The disease is progressive, ultimately resulting in atrophy and heavy lipid deposition. Previous investigators have noted a decrease in the ability of the dystrophic sarcoplasmic reticulum to concentrate Ca2+. More recently, other investigators have shown an abnormal calcium uptake in avian dystrophic sarcoplasmic reticulum. They indicated, using freeze-fracture techniques, that a 90 A particle of the vesicle membrane exhibited a decreased population and suggested that they might be the ATPase involved in calcium transport. Our studies confirm earlier observations of a decreased rate of Ca2+ uptake and Ca2+ binding capacity of dystrophic fragmented sarcoplasmic reticulum vesicles which are isolated from both embryonic and adult pectoralis. These observations correlate in turn with a 75% drop in the Ca:ATP transport efficiency of the dystrophic sarcoplasmic reticulum determined by measuring the rate of 32Pi liberation from gamma-ATP32 during active calcium transport by the isolated sarcoplasmic reticulum SR. In addition, we have found a quantitative deficiency in a 65,000 dalton component of the dystrophic fragmented SR at the time of myoblast fusion by measuring 35S-Methionine incorporation into the SR, coupled to high resolution polyacrylamide gel electrophoresis and radioautography. Analysis of total tissue calcium by atomic absorption spectroscopy revealed a decrease in the total calcium content of dystrophic muscle.
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PMID:Ca2+ binding, ATP-dependent Ca2+ transport, and total tissue Ca2+ in embryonic and adult avian dystrophic pectoralis. 75 24

The acceptance of a syndrome as a distinct nosological entity depends upon our ability to demonstrate that it consistent genetic, pathological and biochemical abnormalities. During the past two decades the application of enzyme histochemistry and electronmicroscopy to the study of biopsy muscle from patients from a variety of ill-defined neuromuscular disorders has enabled us to classify them with much greater precision. This approach, together with increasingly sophisticated electrophysiological techniques, has lead to a much clearer separation of neurogenic and primarily myopathic disorders with a consequent shrinkage in the category of pure muscular dystrophy. Perhaps the most useful application of morphological techniques alone has been in the field of congenital and metabolic myopathies, the histochemical and ultrastructural abnormalities in some cases providing valuable clues to the pathogenesis or even the aetiology of the underlying disease process. This applies particularly to the various glycogen storage diseases affecting skeletal muscle, disorders in which there appear to be structural and functional abnormalities of muscle mitochondria or in which excessive amounts of lipid are stored in muscle fibres. In this communication the histochemical and ultrastructural characteristics of these diseases will be detailed, their possible significance discussed and the relative non-specificity of some of these morphological abnormalities will be noted. A comment will be made on the frequency with which simple Type II fibre atrophy (as demonstrated by the myofibrillar ATPase preparation) may be accompanied by gross and bizarre ultrastructural abnormalities, e.g. in the myopathy accompanying chronic renal failure. Such inconsistencies underline the fact that it is not always possible to demonstrate a close correlation between histochemical and ultrastructural abnormalities in muscle disease. However, it should be emphasized that the combined approach is essential to the rational morphological study of these disorders.
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PMID:Correlations between histochemical and ultrastructural studies of diseased muscle. 123 67

It is believed that one muscle fiber consists of one fiber type determined by its innervating neuron. In biopsied muscles of Duchenne muscular dystrophy (DMD), however, the author has incidentally found a double-typed fiber which is divided into inner and outer parts. The author termed it a "boiled-egg fiber". The author has examined the appearance rate of the boiled-egg fibers on 682 biopsied muscles obtained from patients with various neuromuscular disorders, and classified the types of the inner and outer parts of the boiled-egg fibers by ATPase staining. Boiled-egg fibers were recognized in 17 cases out of 60 with DMD, 5 out of 146 with other types of muscular dystrophy and 6 out of 94 with myositis. No boiled-egg fiber was found in the remaining 382 cases with other disorders which did not represent necrosis with regeneration of muscle fibers. The total number of boiled-egg fibers was 235 with 192 in DMD and 43 in other disorders. 197 of 235 (83.8%) had the same type for both inner and outer parts and remaining 38 (16.2%) had different types for their inner parts. In 133 of 235 (56.6%), the inner parts were type 2C fibers. Boiled-egg fibers were segmentally found with the length of several hundred micrometers. The above findings suggest that boiled-egg fibers reflect an abnormal regenerating process. It remains to be clarified whether or not inner and outer parts of boiled-egg fibers are double-innervated respectively.
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PMID:[The significance of boiled-egg fibers in biopsied muscles of neuromuscular disorders]. 173 23


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