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Query: UMLS:C0024591 (malignant hyperthermia)
 2,353 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lactic acid, glucose, creatine phosphokinase (CPK) and some mineral components were determined in the blood of piglets before and after a halothane test of five minutes (only before for CPK). Two different experimental groups were studied: 222 Pietrain piglets from an INRA experimental herd, and 325 piglets from the Large White, French Landrace and Belgian Landrace breeds entering performance testing stations. Animals reacting positively to halothane ("MHS" piglets) have significantly higher blood levels of lactic acid and potassium before anesthesia than normal animals. CPK is also higher, except for the Belgian Landrace: in this breed CPK shows the same average value and distribution in the two groups of piglets (normal and MHS). There are also breed differences in blood magnesium, independently of the reaction to halothane. But the breed differences observed in lactic acid and CPK are related to the proportion of MHS piglets in each breed. Anesthesia by means of halothane lowers the measured blood characteristics--except for glucose--in normal animals, and rises them--except for potassium--in MHS piglets. The results are discussed in view of the incomplete discrimination between the two types of pigs, with a 5 minutes test, and, particularly, considering possible breed differences in that respect.
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PMID:[Blood characteristics of some french pig populations. Relationships with the malignant hyperthermia syndrome (author's transl)]. 54 25

Two cases of malignant hyperthermia with different clinical courses are reported. The patients showed the classical signs of malignant hyperthermia consisting of tachycardia, tachypnoea, ocasional peripheral cyanosis, high body temperature as well as characteristic rise in serum enzymes. In one of the patients the symptoms were recognized early during the operation. The immediate commencement of therapy with ice-cooled. Ringer-Lactate-Solution, Procainmedication, Corticoids as well as physical body cooling favourably influenced the clinical course and the patient survived. In both cases the patients underwent succinylcholine and halothane anaesthesia, but the symptoms of the second patient appeared after the reduction of anaesthesia. In spite of vigorous therapy the hyperpyrexia resulted in heart arrest and death. Morphologically, both patients showed signs of preexistent myopathy with volumetric alterations of the muscle fibres, centralisation of the nuclei and acute muscle fibre necrosis. On the basis of the observed variable course, the various symptom complexes reported in the literature to data are reviewed. A detailed discussion of the "carrier problem" and the available treatment possibilities is also made. Realising that malignant hyperthermia is an inheritable disease, prophylactic measures such as, f.i. the issue of medical certificates to the patient and his relatives are suggested.
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PMID:[Report on 2 cases of malignant hyperthermia with different clinical courses]. 96 90

Metabolic, hemodynamic and neuroendocrine responses to halothane were measured in five normal and five malignant hyperthermia-susceptible (MHS) swine. Constant-volume ventilation was used. There was no therapeutic intervention. In NHS animals, blood lactate concentrations increased first, and the initial increases appeared to be non-hypoxic in origin. Lactate concentrations increased progressively to more than 20 mum/ml. Whole-body oxygen consumption increased almost twofold, and hind limb muscle oxygen consumption increased almost threefold. Extrapolated increases in muscle oxygen consumption accounted for about 55 per cent of the increase in whole-body oxygen consumption. Respiratory and metabolic acidosis, marked hyperkalemia, and increases in catecholamines and temperature occurred secondarily and were accompanied by progressive circulatory failure.
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PMID:Halothane-induced porcine malignant hyperthermia: metabolic and hemodynamic changes. 124 73

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

Resting metabolic rate and the energy cost of performing a specific (light work load on a bicycle ergometer were measured in nine subjects susceptible to malignant hyperpyrexia (MHS) and nine control subjects, both fasting and following a 600-kcal meal. Blood glucose, lactate, pyruvate and serum triglycerides, thyroxine, cortisol, creatine kinase, growth hormone, and calcium and potassium levels at rest and immediately following exercise, after fasting and eating, were measured. There was no evidence of increased heat production in the MHS subjects compared with controls. The MHS subjects, however, showed a complete absence of dietary-induced thermogenesis with exercise. Compared with the controls, MHS subjects had higher insulin levels for essentially the same blood glucose values. Triglycerides in the MHS group rose steadily over the course of the experiment, whereas in the controls they did not vary from the initial value. Lactate did not rise as much with exercise in the MHS group but did nor fall with rest, and pyruvate did not change from resting fasting values, whereas in the controls it rose steadily. Differences were also found in thyroxine and cortisol levels between the MHS and control groups. The shunting of blood away from thermogenic tissue is suggested as a mechanism for the absence of diet-induced thermogenesis with exercise in the MHS group and the possibility of an underlying abnormality of cardiovascular (sympathetic) control mechanisms in these subjects is discussed. The biochemical abnormalities are discussed in relation to previous biochemical data from MHS humans and pigs and in relation to the abolition of dietary-induced thermogenesis.
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PMID:Metabolic rate and blood hormone and metabolite levels of individuals susceptible to malignant hyperpyrexia at rest and in response to food and mild exercise. 724 57

We hypothesized that IM halothane and caffeine injection increases local lactate concentration dose-dependently in malignant hyperthermia-susceptible (MHS) and nonsusceptible (MHN) pigs and that the hypermetabolic reaction measured by regional distribution of lactate and carbon dioxide is limited to a small muscle volume. Microdialysis probes were placed in the hindlimbs of 7 MHS and 7 MHN pigs and perfused with Ringer's solution. After equilibration, boluses of increasing halothane and caffeine concentrations were injected. For the second hypothesis regarding regional distribution, microdialysis probes were positioned in 7 MHS and 6 MHN pigs at the injection site for halothane and caffeine and at a distance of 10 mm and 25 mm. Lactate was measured in the dialysate by spectrophotometry. In addition, PCO2 was measured in the halothane experiments. Halothane and caffeine increased IM lactate dose-dependently in MHS pigs significantly more than in MHN pigs. Lactate and PCO2 were increased only at the injection site but not at 10 mm and 25 mm distance. MH susceptibility leads to a leftward shift of the dose-response curve for IM lactate after local injection of halothane and caffeine. The increase of lactate and carbon dioxide levels after local MH trigger injection is limited to a small area around the probe.
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PMID:The dose-response relationship and regional distribution of lactate after intramuscular injection of halothane and caffeine in malignant hyperthermia-susceptible pigs. 1642 44

(1)H-NMR has been used to study the evolution of water proton transversal relaxation times in ageing skeletal muscles of normal and halothane-positive Pietrain pigs. Malignant hyperthermia was confirmed by the caffeine contracture test. Lactic acid, creatine phosphate, and ATP levels in muscle biopsies were measured by biochemical analysis. The NMR dynamic results revealed malignant hyperthermia, but knowledge of animal age and muscle type improved significantly the detection ability. The NMR results revealed large differences between muscles. Halothane sensitivity detection seems to be less affected by animal age, than by muscle effect but discrimination was more efficient in the older animal group. It is concluded that (1) H-NMR is a suitable method for diagnosing halothane sensitivity on a well identified muscle biopsy and that water dynamics might be related to acidosis in muscle fibres.
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PMID:NMR relaxation of water protons in normal and malignant hyperthermia-susceptible pig muscle. 2205 42

Mutations in the skeletal muscle Ca2+ release channel, the type 1 ryanodine receptor (RYR1), cause malignant hyperthermia susceptibility (MHS) and a life-threatening sensitivity to heat, which is most severe in children. Mice with an MHS-associated mutation in Ryr1 (Y524S, YS) display lethal muscle contractures in response to heat. Here we show that the heat response in the YS mice is exacerbated by brown fat adaptive thermogenesis. In addition, the YS mice have more brown adipose tissue thermogenic capacity than their littermate controls. Blood lactate levels are elevated in both heat-sensitive MHS patients with RYR1 mutations and YS mice due to Ca2+ driven increases in muscle metabolism. Lactate increases brown adipogenesis in both mouse and human brown preadipocytes. This study suggests that simple lifestyle modifications such as avoiding extreme temperatures and maintaining thermoneutrality could decrease the risk of life-threatening responses to heat and exercise in individuals with RYR1 pathogenic variants.
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PMID:Adaptive thermogenesis enhances the life-threatening response to heat in mice with an Ryr1 mutation. 3303 2