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)

Two patients in a family of exertion-induced heat stroke were reported. Case 1: A 23-year-old male, paternal cousin of case 2, was admitted to our hospital because of loss of consciousness during running under a burning sun. On physical and neurological examinations, he was deeply comatose with high fever, tachycardia, and increased deep tendon reflexes. Laboratory findings disclosed rhabdomyolysis, acute renal failure, disseminated intravascular coagulation, liver injury, and brain edema. He recovered after intensive cooling, some antibiotics, glycerol and sodium dantrolene administration. Case 2: A 19-year-old male experienced loss of consciousness and high fever during playing soccer at 15 years of age, and was admitted to a hospital. On admission, he had high fever of 38.7 degrees C, and increased serum CK level. He recovered two weeks after admission. He was readmitted to our hospital to evaluate the predisposition for malignant hyperthermia. His physical and neurological examinations showed no abnormalities. Routine laboratory findings were within normal limits. Muscle biopsy findings of cases 1 and 2 were mildly increased number of fibers with centrally placed nuclei. Caffeine test on skinned muscle fibers from the biopsies showed normal response in both type 1 and 2 fibers. The present patients were diagnosed as having exertion-induced heat stroke, but with no increased muscle fiber sensitivity to caffeine, suggesting that the pathomechanism differs from that of malignant hyperthermia induced by malfunction of sarcoplasmic reticulum.
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PMID:[Two familial cases with exertion-induced heat stroke--relationship to malignant hyperthermia]. 139 27

Diltiazem inhibited and antagonized the abnormal contractures induced by halothane, caffeine and potassium chloride in isolated skeletal muscle from pigs susceptible to malignant hyperpyrexia (MHS). Contractile responses to caffeine and electrical stimulation also were suppressed by diltiazem in control tissue. Similar effects were obtained in the presence of dantrolene. In both MHS and control preparations, diltiazem antagonized caffeine-induced contractures in the presence of maximal effective concentrations of dantrolene, and the converse was true also. In MHS and control preparations detubulated by glycerol, diltiazem did not inhibit or antagonize caffeine-induced contractures while dantrolene did. Diltiazem seems to modify contractile responses at the level of the transverse tubule membrane by inhibiting the inward flow of extracellular Ca2+, while dantrolene inhibits Ca2+ release directly from the sarcoplasmic reticulum. Ca2+ influx through transverse tubules may be important in the aetiology of the MH syndrome.
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PMID:Effect of diltiazem and dantrolene on the contractility of isolated malignant hyperpyrexia-susceptible porcine skeletal muscle. 273 Aug 30

It has been speculated that, in malignant hyperthermia-susceptible (MHS) individuals, an abnormality of sympathetic activity is seen during stressful situations, such as exercise. The authors investigated whether muscle metabolism in eight MHS subjects, at rest and during moderate and heavy short-term exercise, is different then that in normals. Leg exchange of energy substrates (glucose, lactate, and glycerol) was quantified by measuring leg blood flow and arterial-venous concentration differences. Muscle biopsies were also performed, and ATP, glycogen, and lactate were analyzed. Catecholamines and oxygen uptake were also measured. The study was performed at rest with subjects in the supine position and during two periods (40% and 80% of the subjects maximal oxygen uptake, respectively) on a bicycle ergometer. The principal finding of the study was that there was no major difference in oxygen uptake or leg exchange of glucose, lactate, and glycerol between MHS-subjects and previously standard normals during different grades of exercise. Furthermore, muscle metabolites and plasma catecholamines did not differ between the groups. This study indicates a normal sympathetic activity and muscle metabolism in MHS subjects during rest, as well as during moderate and severe exercise. The authors' results do not support the opinion that persons with positive in vitro tests for MH should restrict their physical activity.
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PMID:Effects of graded exercise on leg exchange of energy substrates in malignant hyperthermia susceptible subjects. 363 4

Hepatic metabolism during porcine malignant hyperthermia (MH) was investigated in seven Pietrain pigs. The estimated hepatic blood flow decreased during MH, but an increase in oxygen extraction enabled the splanchnic oxygen uptake to be maintained. There was a large release of glucose and potassium from the liver in MH which made an important contribution to the hyperglycaemia and hyperkalaemia. Measurement of hepatic uptake of the precursors of gluconeogenesis, lactate, glycerol and alanine, showed that glucose efflux from liver was derived mainly from glycogenolysis. Lactate uptake by the liver increased during MH, and there was no evidence of hepatic lactate production during the profound acidosis as suggested by in vitro studies with the isolated liver. There was no evidence of major abnormality of hepatic function during porcine MH.
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PMID:Porcine malignant hyperthermia. VII: Hepatic metabolism. 699 Sep 47

The halothane test was performed under different conditions in 10 halothane-sensitive growing pigs (Landrace, line 01). Haematological and metabolic changes in blood were monitored during the handling of the pigs before the test, during the exposure to halothane and thereafter. Already in connection with the catching and fixation of the pigs, the levels of haemoglobin in blood, and of glucose, lactate and potassium in plasma increased significantly. However, the concentration of glycerol was not raised before the occurrence of the malignant hyperthermia. While the level of potassium decreased already from the beginning of the halothane exposure until the development of symptoms, the values of haemoglobin, glucose and lactate continued to increased. The level of the free fatty acids did not show any changes during the experimental period. An infusion of phentolamine reduced the increase of haemoglobin and potassium and an infusion of propranolol reduced the increase of haemoglobin and glycerol significantly, without any effect on the result of the halothane test. By an anaesthesia, starting 30 minutes before the exposure to halothane, the development of the typical halothane reaction was obviated for at least 10 minutes. Observed metabolic changes during a simultaneous epinephrine administration were exclusively due to its adrenergic effects.
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PMID:[The effect of anesthesia, of an alpha or beta adrenergic blockade in conscious and of adrenaline in anesthetized halothane-positive swine on hematologic and metabolic parameters in the blood during the course of halothane exposure]. 812 1

The purpose of this study was to show the behaviour of the plasma level of catecholamines in stress-susceptible pigs during an acute stress and to gain new insights in the role of catecholamines in the initiation of malignant hyperthermia. Therefore, a halothane challenge test was performed in stress-susceptible growing pigs, and the changes of haematocrit, hormones and metabolites were monitored during the handling before the test, during halothane exposure and thereafter. Already in connection with the handling before the test, haematocrit values and plasma levels of epinephrine, norepinephrine, glucose, lactate and potassium increased significantly. However, the plasma concentration of cortisol and free glycerol increased gradually and the level of nonesterified fatty acids did not show any changes. While the levels of catecholamines and potassium decreased already during halothane exposure, haematocrit values and concentrations of glucose and lactate continued to increase. The present results indicate that the catecholamines are not involved in the initiation of malignant hyperthermia.
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PMID:[Effect of acute stress on plasma levels of catecholamines and cortisol in addition to metabolites in stress-susceptible growing swine]. 899 69