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

The results are reported of single muscle fiber uptake of tritiated leucine in muscle biopsy material from Duchenne dystrophy and Charcot-Marie Tooth disease. The uptake in the two conditions is compared and suggests that the previously reported increase in synthesis of cytoplasmic proteins in muscular dystrophy are probably related to regenerative efforts by the muscle fibers.
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PMID:The incorporation of 3H (G) L-leucine into single muscle fibers in Duchenne dystrophy and Charcot-Marie Tooth disease. 26 56

The autoradiographic findings using tritiated leucine are described in muscle biopsy material from five patients with progressive muscular dystrophy (P.M.D.), three with motor neuron disease (M.N.D.) and four with Charcot-Marie-Tooth disease (C.M.T.). In progressive muscular dystrophy there is a marked increase in uptake of leucine into cytoplasmic proteins and precursors, and reduced incorporation into structural protein. In Charcot-Marie Tooth disease muscle there is a significantly increased uptake into cytoplasmic elements and a normal uptake into structural protein. In motor neuron disease the uptake into cytoplasmic elements appears normal but is reduced into structural proteins. The abnormal uptake in C.M.T. could be explained as a product of regenerative efforts associated with reinnervation. However, the abnormal uptake may represent the primary effects of gene action in the muscle, as seems probable in progressive muscular dystrophy.
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PMID:An autoradiographic study of muscular dystrophy, motor neuron disease and Charcot-Marie-Tooth disease. 83 61

A study of the incorporation of hydrogen 3 (3H) leucine into skeletal muscle in patients with human muscular dystrophy and motor neuron disease showed uptake in cytoplasm and myofibrils. The techniques used were light and electron microscopy and autoradiography before and after glycerination (Szent-Gyorgyi). The results indicated an increase of 3H leucine uptake into cytoplasm of the dystrophic muscle and a marked drop in incorporation into structural protein. In the patients with motor neuron disease, the normal incorporation into cytoplasm was seen, with reduced uptake into structural protein. These results showed a different protein synthesis pattern in dystrophic and denervated muscle.
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PMID:Myofibrillar incorporation of 3H (G) L-leucine in pgrogressive muscular dystrophy and motor neuron disease. 94 52

The study of 3H leucine incorporation into skeletal muscle of mouse muscular dystrophy (129 ReJ/dy Bar Harbour strain) shows the uptake of isotope into myofibrils. The techniques employed were light and EM autoradiography before and after glycerination (Szent-Gyorgyi 1947). The results indicate a marked drop in uptake of the 3H-Leucine into myofibrils in the dystrophic animals, supporting the contention of Nihei et al (1971) that reduced myosin synthesis occurs in mouse muscular dystrophy.
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PMID:3H leucine incorporation into myofibrils of normal and dystrophic mouse skeletal muscle. 114 51

Assessments were made of the thymus and spleen weights and the total nucleotide, nucleic acid, and protein content as well as the incorporation of [14C]leucine into protein and of [3H]orotate into RNA, in the thymus, spleen, liver, brain, kidney, lungs, heart, pancreas, and skeletal muscle of normal (+/+) and dystrophic (dy/dy) 129 ReJ mice aged 40, 60, or 90 days. The weights of the thymus and spleen were lower at all stages of dystrophy. Total nucleotide and RNA levels per thymus were reduced at 90 days, while total DNA content was decreased at 60 and 90 days. Protein concentrations per thymus were diminished at each stage of the disease. The specific activity of the free amino acid pool and total free nucleotide pool did not show any significant variations in the thymus at any phase of dystrophy. Incorporation of [14C]leucine into protein and of [3H]orotate into RNA was considerably lower in the thymus at each stage of the disease. Total nucleotide content per spleen was decreased at 40 days, with no change at 60 days and followed by an increase at 90 days in the dystrophic mice. DNA, RNA, and protein levels were all reduced in the spleen at each stage of the disease. The specific activity of the free amino acid pool and total free nucleotide pool, as well as the incorporation of [14C]leucine into protein and of [3H]orotate into RNA, showed similar changes in the spleen as noted in the thymus at each phase of dystrophy. These observations indicate that significant alterations in cellular growth occur not only in skeletal muscle and other nonlymphoid organs, but also in the lymphoid organs of dystrophic mice. Such changes in the cellular growth of lymphoid organs could be responsible for an impairment of immunologic responses reflecting thymic atrophy in murine muscular dystrophy.
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PMID:Biochemical changes in progressive muscular dystrophy. XIII. Nucleic acids, proteins, and total nucleotides in the thymus and spleen of dystrophic mice. 241 88

1. Quadriceps muscle protein synthetic rate has been determined in healthy subjects in the post-absorptive (n = 18) and fed (n = 10) states and in patients with a variety of myopathies, by analysis of the enrichment of serial muscle biopsies taken during primed continuous infusion of L-[1-13C]leucine. 2. Quadriceps protein synthetic rates in normal subjects were (mean +/- SD) 0.046 +/- 0.012 and 0.075 +/- 0.014%/h in the post-absorptive and fed states respectively. These results are significantly lower than we previously reported (M. J. Rennie et al., Clinical Science, 1982, 63, 519-523 [1]) but show the same relative differences of direction and magnitude, confirming the effects of feeding previously reported. In patients with muscular dystrophy, muscle protein synthetic rate was, as previously reported [1], much lower in the fed state than in normal subjects. A new finding is that for patients with myotonic dystrophy the rate is also depressed in the post-absorptive state. 3. We suggest that the present estimates in post-absorptive and fed normal subjects be used as reference values for quadriceps mixed muscle protein synthetic rate.
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PMID:Rate of protein synthesis in skeletal muscle of normal man and patients with muscular dystrophy: a reassessment. 334 33

We have studied the structure of myosin heavy chain (MHC) in the pectoralis muscle of genetically dystrophic (Connecticut Strain) and White Leghorn chicks. MHC was alkylated with N-ethylmaleimide, purified by Sepharose-4B chromatography, and cleaved with cyanogen bromide. The MHC CNBr peptides were analyzed by one-dimensional and two-dimensional isoelectric focusing/sodium dodecyl sulfate gradient gels and by amino acid sequencing. Specific changes were detected in the gel patterns which could be correlated with the loss of muscle function as measured by the exhaustion score (the ability of chicks to rise from a reclining position) in three experimental groups (exhaustion scores: less than 3, 10-20, greater than 30). We have also examined the amino acid sequence of a 3-methyl-histidine-containing peptide which originates from the 20-kDa fragment of pectoralis muscle MHC in dystrophic chicks: Val-Leu-Asn-Ala-Ser-Ala-Ile-Pro-Glu-Gly-*Gln-Phe-*Ile-Asp-Ser-Lys-Lys- Ala-Ser-Leu-Gln-Lys-Leu-Gly-Ser-Ile-Asp-Val-(Asp, 3-methylhistidine, Gln). Comparison of the homologous MHC sequences shows two positions at which MHC from dystrophic chicks differs from that of the White Leghorn chicks *(Glu----Gln and Met----Ile). Thus, both the peptide map and sequence analyses demonstrate that in avian muscular dystrophy an abnormal pectoralis MHC is synthesized. It is not yet clear whether the "dystrophic" MHC is a variant MHC or if it arises from the abnormal expression of an earlier developmental form (embryonic or neonatal) of pectoralis muscle MHC.
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PMID:Structure of myosin heavy chain in avian muscular dystrophy. 399 78

To elucidate the metabolic abnormality of musclar dystrophy, 27 kinds of enzyme activity in various organs of control and dystrophic mice were examined. The organs examined included muscle, bone, heart, testis, uterus, spleen, thymus, submaxillary gland, stomach, pancreas, liver, kidney, brain, and lung. The activities of 14 different aminopeptidases, 5 endopeptidases, 4 glycosidases, phosphatase, esterase, and ribonuclease were measured. Most of the enzyme activities were significantly elevated in muscles and bones of dystrophic mice. These organs were similar in their patterns of enzyme abnormality. Among the 14 kinds of aminopeptidase activity studied, the degree of increased activity was greater for the aminopeptidases (AP):Ala-AP, Leu-AP, Met-AP, Phe-AP, Trp-AP, Gly-Pro-Leu-AP. In addition to aminopeptidases, there were significant increases in activities of chymotrypsinlike enzyme, cathepsin C, cathepsin D, several glycosidases and neutral ribonuclease in the muscles of dystrophic mice. Similarly increased enzyme activity was also observed in organs other than muscle and bone. Furthermore, protein content in most organs was higher in dystrophic mice than in those of control mice. These abnormalities were seen in both males and females. The present results suggest that there are extensive abnormalities in the protein metabolism in dystrophic mice. It seems therefore that the therapeutic approach to muscular dystrophy should be studies not only from the well-known abnormality of intramuscular endopeptidases, but from other aspects as well.
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PMID:Various enzyme activities in muscle and other organs of dystrophic mice. 625 14

Interactins between skeletal muscle protein and amino acid metabolism were investigated using C57BL and 129ReJ mice with hereditary muscular dystrophy. On incubation, hind limb muscle preparations from dystrophic mice released large quantities of amino acids, particularly alanine and glutamine which were increased 70% and 40% compared to muscles from carrier or control mice. The increased alanine release did not result from altered alanine oxidation to CO2 or reincorporation into protein. Alanine and glutamine formation from added amino acids were equal with dystrophic and control muscles. Incorporation in vitro of leucine, alanine, and glutamate into proteins of dystrophic muscle was 3- to 7-fold greater than control muscle, and the incorporation in vivo of [3H]- or [14C]arginine into muscle proteins was greater in extent and earlier in time with dystrophic as compared to control muscle. Proteins were also labeled in vivo using [guanido-14C]arginine. On incubation of these muscles in vitro, a 100% greater loss of label from protein was observed with dystrophic as compared to control preparations, and the appearance of label in the media was correspondingly increased. Sodium dodecyl sulfate-gel electrophoresis of dystrophic skeletal muscle showed numerous protein bands to be reduced in density, but autoradiographic studies demonstrated that these same bands were more highly labeled in vitro by [35S]methionine in dystrophic than in control muscle. Although insulin stimulation of glucose uptake was markedly blunted in dystrophic muscle, insulin inhibited alanine and glutamine release equally from both control and dystrophic muscle. These data indicate that alanine and glutamine formation and release are increased in hereditary mouse muscular dystrophy. An accelerated degradation and an increased resynthesis of many muscle proteins were also observed in dystrophic compared to control animals. This increased proteolysis may account for the increased alanine and glutamine formation in dystrophic muscle.
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PMID:Skeletal muscle protein and amino acid metabolism in hereditary mouse muscular dystrophy. Accelerated protein turnover and increased alanine and glutamine formation and release. 689 25

1. To investigate the effects of starvation, elective surgery, accidental injury and other clinical conditions on the metabolism of branched-chain amino acids in man, we have measured the basal concentration of leucine and the removal of metabolic effects of infused L-leucine. 2. The blood concentration of leucine as significantly increased by surgery, starvation and accidental injury, and decreased in cirrhosis. It tended to increase in diabetes and was unaffected by muscular dystrophy. 3. The half-life of infused leucine was nearly doubled by 4 days of complete starvation, unaltered by surgery and decreased by severe accidental injury, Infusion with Intralipid, which increased free fatty acid and ketone-body concentrations, had no effect on the removal of a leucine load. The clearance rate of infused leucine was reduced in diabetes and muscular dystrophy and increased in cirrhosis. 4. The effects of infused leucine on blood glucose and ketone bodies differed according to the groups studied. 5. Since the traumatized patients were given sufficient energy and nitrogen and disposed of a leucine load at a different rate from the starved patients, the causes of the increase in blood concentration of leucine in these two conditions are different.
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PMID:The removal of infused leucine after injury, starvation and other conditions in man. 742 95


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