Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024591 (malignant hyperthermia)
 2,353 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A comparison was made of muscle from two locations in both the longissimus and the semitendinous muscles of normal and malignant hyperthermia-susceptible swine. Serial frozen sections were stained for alkali-stable adenosine triphosphatase (ATPase), phosphorylase, and the oxidative enzymes succinate dehydrogenase and reduced nicotinamide adenine dinucleotide (NADH)-diaphorase. Myofiber types were identified on the basis of these staining reactions. There was no consistent statistically significant difference between muscle from normal and muscle from susceptible swine with any system of fiber classification. This is contrary to several published reports but consistent with physiologic studies which indicate that both oxidative and glycolytic pathways are abnormally active during the onset of malignant hyperthermia.
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PMID:Histochemical observations on muscle from normal and malignant hyperthermia-susceptible swine. 644 66

In porcine malignant hyperthermia-susceptible (MHS) skeletal muscles, calcium release is abnormal and resting calcium may be elevated. Thus MHS muscles may have prolonged twitch relaxation and lower fusion frequencies, which would be augmented by inhibition of sarcoplasmic reticulum (SR) Ca2+ adenosine triphosphatase (ATPase) activity; bundles of intact muscle cells from MHS and normal pigs were used to investigate this possibility. Cooling and low-frequency stimulation, in combination, enhanced twitch fusion and prolonged twitch relaxation significantly more in MHS than in normal muscles (e.g., 34 +/- 4% versus 16 +/- 4% fusion, and 82.4 +/- 9.4 ms versus 43.2 +/- 7.8 ms half-relaxation time, for MHS and normal muscles, respectively). Similarly, inhibition of the SR Ca2+ ATPase by cyclopiazonic acid resulted in significantly greater twitch fusion in MHS muscles. These results were consistent with predicted effects of enhanced SR Ca2+ release and/or elevated resting calcium in MHS muscles and indicate that cooling during a malignant hyperthermia crisis could actually increase the force of muscle contractures.
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PMID:Malignant hyperthermia: effects of sarcoplasmic reticulum Ca2+ pump inhibition. 948 65