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

By the halothane test we determined the development of the syndrome of malignant hyperthermia in pigs of the Belgian Landrace breed with body weight of 20 kg. We found that from 27 animals that were subjected to the test 12 positively reacted to Narcotan - Spofa anaesthesis. Pigs with the syndrome of malignant hyperthermia had considerably higher rectal temperature after anaesthesis, lower PH of venose blood, higher concentration of lactic acid and glucosis in the blood plasma. Halothane-negative animals did not produce and conspicuous changes of these indices. Most differences were statisticaly highly significant.
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PMID:[Utilization of the halothane test in the detection of the malignant hypertension syndrome [MHS] in pigs]. 9 39

Pituitary-adrenal function was investigated in two groups of Pietrain pigs differing by their susceptibility to the malignant hyperthermia syndrome induced by halothane, and in Large White pigs (LW). Plasma basal levels of glucocorticoids, measured by a protein binding technique, and plasma ACTH concentrations, determined by radioimmunoassay, did not differ according to halothane susceptibility but were higher in LW pigs compared with Pietrain pigs. The reactivity of the pituitary-adrenal axis to such stressors as exposition to a novel environment or shaking was the same for all experimental groups. The same was true concerning plasma levels of glucocorticoids and ACTH after injection of dexamethasone and response of the adrenal cortex to a standard dose of ACTH. These results demonstrate that LW pigs have a higher tonic secretion of ACTH than Pietrain pigs, but with identical phasic response to stimulations. Halothane susceptibility by itself appears to have no influence of pituitary-adrenal function.
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PMID:Behavioural and pituitary-adrenal characteristics of pigs differing by their susceptibility to the malignant hyperthermia syndrome induced by halothane anesthesia. 2. Pituitary-adrenal function. 21 55

MHS and normal pigs were anaesthetized with nitrous oxide and diazepam. Halothane 1% was then administered for 1 hr. Immediately before and immediately after the halothane inhalation, 10 g of vastus lateralis muscle was excised. SR was isolated from this muscle. Calcium accumulation by the MHS sarcoplasmic reticulum in the absence of halothane was greater than normal. Halothane in vitro produced a similar increase in calcium uptake into both the MHS and the normal SR. Halothane in vivo significantly reduced calcium accumulation by hyperthermic SR but had no significant effect on calcium uptake into the normal SR. Thus the action of halothane on the MHS sarcoplasmic reticulum is indirect, occurring only in the intact cell. It is possibly a result of the deleterious effect which lack of ATP, a low pH or a high temperature is likely to have on the calcium accumulating mechanism of the SR membrane. Our results suggest that the primary defects of porcine and human malignant hyperthermia are not entirely synonymous.
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PMID:Calcium uptake into muscle of pigs susceptible to malignant hyperthermia: in vitro and in vivo studies with and without halothane. 23 50

Clinical concentrations of anesthetics augment caffeine-induced contracture of frog sartorius muscle; however, anesthetics differ in this characteristic. The potentiation was quantitated using six paired sartorius muscles for each specified concentration of anesthetic and controls. At a concentration of 1 MAC, the greatest potentiation occurred with 2 mM caffeine for all anesthetics studied. Under these conditions the order of magnitude of augmentations was: chloroform (15 times); halothane (11 times); methoxyflurane (10 times); cyclopropane (5 times); enflurane (4 times); isoflurane (3 times); diethyl ether (2 times); Baxter 3224 (2 times); fluroxene (1.4 times); nitrous oxide (1.3 times). Halothane at .5 MAC augments the 2 mM caffeine-induced contracture almost seven times, and at 2 MAC almost 13 times, whereas 2 MAC isoflurane potentiates the caffeine-induced contracture only four times and 4 MAC diethyl ether only two and a half times. It is postulated that those anesthetics that most potentiate caffeine-induced contracture may be the most potent triggering agents of malignant hyperthermia.
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PMID:An in-vitro model of malignant hyperthermia: differential effects of inhalation anesthetics on caffeine-induced muscle contractures. 30 36

To examine the function of sarcoplasmic reticulum (SR) in malignant hyperthermia, SR was isolated from semitendinosus muscle of normal and genetically susceptible Poland China swine. Determinations included rate of calcium binding (oxalate absent), rate and capacity of calcium uptake (oxalate present), and spontaneous calcium release (in the absence of ionic depolarization or calcium) with and without halothane, using the millipore filtration technique. Rate of calcium binding, and rate and capacity of calcium uptake were decreased, and spontaneous calcium release was greater in SR fragments from susceptible swine as compared to those from normal swine. Halothane 0.5% slightly increased the rate of calcium binding in susceptible and normal SR. Above 1%, halothane decreased calcium binding rate, and uptake rate and capacity, and increased calcium release similarly in susceptible and normal SR. These differences in SR function were insufficient to explain the etiology of malignant hyperthemia, nor did the effect of halothane account for its triggering action.
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PMID:Skeletal muscle sarcoplasmic reticulum in porcine malignant hyperthermia. 49 49

Halothane, at clinical concentrations, depolarizes the plasma membrane of skeletal muscle from Poland China pigs susceptible to malignant hyperthermia but does not affect the resting membrane potential of muscle from normal poland China pigs, mice, or frogs. The depolarization is reduced or partially reversed in the presence of dantrolene sodium. We suggest the possibility that malignant hyperthermia may be initiated by this abnormal depolarization of skeletal muscle by halothane.
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PMID:Role of plasma membrane defect of skeletal muscle in malignant hyperthermia. 51 15

This study compares several methods for diagnosing susceptibility to malignant hyperthermia, using two groups of Poland China swine narrowly defined as genetically susceptible or normal (five pigs each) depending respectively on their response to halothane or to halothane and succinylcholine. Vastus medialis muscle biopsies were excised under thiopental-N2O-O2 anesthesia and used for examination of (1) contracture responses to halothane, (2) contracture responses to caffeine and halothane-caffeine, and (3) adenosine triphosphate (ATP) depletion with and without halothane. All studies were performed in organ baths at 37 C. Halothane alone produced contractures in two susceptible and one normal preparation; caffeine always produced a contracture at lower concentrations in susceptible muscle; caffeine-halothane contractures in susceptible muscle occurred at lower mean caffeine concentrations, but there was some overlap of individual values; mean ATP depletion was greater in susceptible muscle, but with considerable overlap. Comparisons with the findings of others were hampered by use of absolute rather than comparative values for tension, e.g., grams, rather than grams per cross-sectional area or fraction of peak tension. Examination of the complete dose-response curve provided the best comparative information and caffeine was the consistent predictor of susceptibility.
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PMID:Muscle contractures and adenosine triphosphate depletion in porcine malignant hyperthermia. 57 59

A 31-year old male developed malignant hyperthermia (MH) during the initial minutes of Halothane induction. CPK rose to 6120 U/ml and decreased to normal levels as the patient became afebrile over a 10 day period of cooling measures and metabolic management. Muscle weakness, predominantly proximal and depressed deep tendon reflexes were found upon examination during convalescence. Muscle biopsy showed neurogenic changes characterized by fiber type grouping and targetoid fibers. CPK was elevated in one of the patient's children. This case supports the view of underlying hereditary neuromyopathy in MH.
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PMID:Neuromyopathy in malignant hyperthermia. 58 Feb 62

The rates of acid production were compared in thin strips of muscle biopsy samples isolated from malignant hyperpyrexia and control vastus internus human muscle. Halothane doubled the rate of acid production by malignant hyperpyrexia susceptible muscle but had no effect on control samples. This increased rate of release of acid from muscle was not from lactate. In addition, the pyruvate dehydrogenase activity of both control and malignant hyperpyrexia muscle samples was not stimulated by halothane.
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PMID:Effect of halothane on the rate of acid production, lactate production and pyruvate dehydrogenase activity of malignant hyperpyrexia human muscle. 67 67

Skeletal muscle from malignant hyperthermic (MH) pigs incubated at 37 C in 2.3 mM calcium-Krebs-Ringer solution contracts spontaneously when exposed to halothane. In contrast, halothane did not induce contracture in MH muscle incubated in 2.3 mM calcium-Krebs-Ringer solution at 25 C or in calcium-free Krebs-Ringer's solution at 37 C. Halothane did not induce contracture in normal control muscle in 2.3 mM Krebs-Ringer solution at 25 or 37 C. In the presence of halothane, addition of caffeine produced greater contracture in MH muscle than in normal controls. Halothane-caffeine-induced contractures of MH and control muscles at 25 and 37 C were similar. Elucidation that under certain experimental conditions halothane induces contracture in MH muscle, but not in normal muscle 1) may aid in development of a diagnostic test; 2) establishes further evidence for skeletal muscle as the target tissue for anesthetic-induced MH; 3) suggests that halothane may affect systems that regulate sarcoplasmic calcium concentration below contracture threshold in MH muscle. (Key words: Hyperthermia, malignant; Anesthetics, volatile, halothane; Ions, calcium; Muscle, skeletal, malignant hyperthermia.).
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PMID:Porcine malignant hyperthermia: effects of temperature and extracellular calcium concentration on halothane-induced contracture of susceptible skeletal muscle. 111 84


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