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)

Our aim was to develop an exercise protocol using 31P-magnetic resonance spectroscopy (31P-MRS), which can discriminate between malignant hyperthermia-susceptible (MHS) individuals and controls. MRS spectra of the forearm muscles were recorded at rest, during and after a standardized exercise protocol in 10 MHS patients and compared with spectra obtained in 10 controls. There was no difference in resting intracellular pH (pHi) or PCr/(Pi+PCr) ratio between the groups (PCr = phosphocreatine, Pi = inorganic phosphorus). At the end of the exercise and during the initial recovery phase, the pHi and PCr/(Pi+PCr) ratio were significantly lower in the MHS group ([pHi: 6.37 (0.07) for MHS vs 6.70 (0.05) for controls, P < 0.005; PCr/(Pi+PCr): 0.784 (0.017) for MHS vs 0.954 (0.020) for controls, P < 0.0005]). For PCr/(Pi+PCr), complete separation between the two groups was observed during the initial recovery phase. The mean recovery time of PCr/(Pi+PCr) was 0.57 min for the control group and 1.28 min for the MHS group. The slower recovery of PCr/(Pi+PCr) is likely to be caused by a combination of several factors, including the lower pHi in MHS subjects at the start of recovery (inhibiting ATP production) and excessive sarcoplasmic calcium overload (causing continued enzyme activation and ATP consumption). Our exercise protocol can be a valuable adjunct to discriminate between MHS and non susceptible subjects.
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PMID:Slower recovery of muscle phosphocreatine in malignant hyperthermia-susceptible individuals assessed by 31P-MR spectroscopy. 940 43

Phosphorus magnetic resonance spectroscopy (P-MRS) has now been used in the investigation of muscle energy metabolism in health and disease for over 15 years. The present review describes the basics of the metabolic observations made by P-MRS including the assumptions and problems associated with the use of this technique. Extramuscular factors, which may affect the P-MRS results, are detailed. The important P-MRS observations in patients with mitochondrial myopathies, including the monitoring of experimental therapies, are emphasized. The findings in other metabolic myopathies (those associated with glycolytic defects or endocrine disturbances) and in the destructive myopathies (the dystrophies and the inflammatory myopathies) are also described. Observations made in normal and abnormal fatigue, fibromyalgia, and malignant hyperthermia are considered. Finally, a summary of the possible diagnostic use of P-MRS in exercise intolerance is provided.
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PMID:Insights into muscle diseases gained by phosphorus magnetic resonance spectroscopy. 1095 34

Malignant hyperthermia (MH) is a metabolic myopathy with an abnormal release of calcium by the sarcoplasmic reticulum (SR), triggered by volatile anesthetics and succinylcholine. Similarly, caffeine enhances Ca(2+)release by the SR in vitro. In a prospective, randomized study, high-energy phosphates were studied by intramuscular 31-phosphorus magnetic resonance spectroscopy ((31)P-MRS) in 10 MH-susceptible (MHS) and 7 MH-nonsusceptible (MHN) subjects before and after injection of 0.5 ml caffeine (20 mM). Intramuscular energy balance, measured by the ratios of P(i)/PCr and P(i)/gamma-ATP, did not differ between MHS and MHN patients before and after intramuscular caffeine injection. However, within each group, P(i)/PCr and P(i)/gamma-ATP increased significantly only in the MHS group. Intramuscular caffeine injection seemed to impair the metabolic balance in MHS individuals. This may reflect a local calcium overload leading to consumption of high-energy phosphates and increase of inorganic phosphate. Intramuscular stimulation by caffeine and (31)P-MRS may provide a valuable tool to investigate MH-related metabolic disturbances.
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PMID:Caffeine impairs intramuscular energy balance in patients susceptible to malignant hyperthermia. 1292 96