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

Sorption properties of sarcolemma preparations isolated from skeletal muscles of normal and E-avitaminous rabbits were studied relative to organic ions. Analysis of isotherms of sarcolemma equilibrium binding of neutral red cations and turquoise direct lightfast "K" anions made it possible to determine the number of positively and negetively charged sorption centres, which fix the mentioned dyes. With E-avitaminous muscular dystrophy the number of the centres increases considerably. A larger number of the positively charged centres fixing the surquoise dye are found both in the control and in case of dystrophy. The calcium ions prevent the neutral red sorption and intensify the turquoise direct sorption. In the sarcolemma preparations isolated from the muscles of the E-avitaminous rabbits the content of calcium ions is almost twice as high and the number of sulphydryl groups is 30-40% less as compare to the normal level. The data presented evidence for structural changes in sarcolemma with E-avitaminous muscular dystrophy.
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PMID:[Structural changes in sarcolemma with E-avitaminosis dystrophy]. 1 66

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

A Ca2+-activated neutral protease activity was examined in muscles of normal and dystrophic hamsters and mice. Light grey and golden brown strains of normal and B10 14.6 strain of dystrophic hamsters were used. Normal and dystrophic mice were of the Bar Harbor 129 ReJ strain. Enzyme activity was measured in the post myofibrillar fraction (homogenate) and in the 75,000 x g pellet (particulate fraction) and supernatant using purified myofibrils. In normal and dystrophic hamsters or mice, the Ca2+-activated neutral protease was most active in the supernatant followed by the homogenate and particulate fractions. As compared to fractions from normal muscle, enzyme activity was significantly elevated in all 3 fractions from dystrophic muscles of hamsters and mice. Both homogenate and supernatant fractions from muscles of normal hamsters had significantly higher enzyme activity than those of normal mice. Enzyme activity was similar in the particulate fraction. Similarly enzyme activity in the 3 fractions from dystrophic hamster and mouse muscles showed no significant difference. It is suggested that the Ca2+-activated neutral protease may be involved in muscle fibre necrosis in muscular dystrophy.
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PMID:Increased calcium-activated neutral protease activity in muscles of dystrophic hamsters and mice. 43 97

The stability of washed erythrocytes from patients with muscular dystrophy was determined in hypotonic phosphate buffered sodium chloride. Control cells were more stable than cells from Duchenne and myotonic patients. After pretreatment of the cells with phospholipase from pancreas, snake venom or bee venom in the presence of 14 mmol/l Ca2+, the order of osmotic stability in the 3 groups was not changed. In isotonic phosphate buffered NaCl, however, the erythrocytes of the myotonic patients were much more stable than the cells of the Duchenne and the control group. The lytic process was further studied in control cells with pancreatic phospholipase. 21 +/- 3 (S.E.M.) % of the cells were lysed. This process was (partly) prevented by omitting the phospholipase, by replacement of Na+ by K+ or Li+, by lowering the Ca2+ concentration, by omitting phosphate, by ouabain, by glucose, by ribose, by sucrose, by tetrodotoxin, a Na+-transport inhibitor. Blocking of the Ca2+ transport by La3+ or mersalyl, greatly stimulated the lytic process.
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PMID:Osmotic stability of erythrocytes in human muscular dystrophy before and after phospholipase treatment. 46 13

Sorption properties of skeletal muscles nuclei in rabbits in normal state and with E-avitaminosis were studied using organic dyes: neutral red (cationic) and turquoise direct light-fast "K" (anionic) and the influence of calcium-modified membrane of nuclei on their sorption. The nuclear surface is established to have both positive and negative charged groups sorbing turquioise direct and neutral red, respectively. The maximum volume of the dyes binding and the dissociation constants of the membrane-dye complex are estimated. It is shown that with muscular dystrophy the number of charged groups of both signs on the nuclear surface decreases. Calcium ions decrease the cationic dye sorption both in the normal state and with dystrophy and insignificantly decrease the anionic dye with dystrophy.
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PMID:[Characteristic of sorption properties of skeletal muscle nuclei in the normal state and with E-avitaminotic muscular dystrophy]. 54 32

Possible roles of neurotrophic mechanisms and muscle activity in the contractile abnormalities of muscular dystrophy were studied by comparing human dystrophic muscle to denervated and immobilized muscle. As evident in denervated muscle from the decreased acceleration of twitch development (decreased active state intensity of shortening), and isoproterenol-induced decrease of twitch with shortened decay of the active state, part of the abnormality in the subcellular calcium transport system in dystrophic muscle seems to be influenced by disordered neural regulation. Other active state abnormalities relating to activation processes and contractile proteins in dystrophic muscle were also demonstrated in both denervated and immobilized muscle, with some being more marked in immobilized muscle. The findings indicate that a neurogenic hypothesis cannot entirely explain the pathogenesis of progressive muscular dystrophy.
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PMID:Active state properties of denervated and immobilized muscle: comparison with dystrophic muscle. 56 93


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