Histological support for the difference between malignant hyperthermia susceptible (MHS), equivocal (MHE) and negative (MHN) muscle biopsies.

The aim of this study was to find, using modern techniques, any histological differences in muscle biopsies between malignant hyperthermia (MH) susceptible (MHS), MH equivocal (MHE) and MH negative (MHN) patients. On the basis of the European MH contracture test carried out in 83 patients, 23 were shown to be MHS, nine MHE and 51 MHN. Four lesions were found with a significantly high frequency in MHS and MHE biopsies: muscle fibre hypertrophy and atrophy, internal nuclei and myofibrillar necrosis.

In vitro contracture test for diagnosis of malignant hyperthermia following the protocol of the European MH Group: results of testing patients surviving fulminant MH and unrelated low-risk subjects. The European Malignant Hyperthermia Group.

Background: Determination of sensitivity and specificity of the in vitro contracture test (IVCT) for malignant hyperthermia (MH) susceptibility using the European MH Group (EMHG) protocol has been performed in some laboratories but only on a small sample from the combined EMHG. Thus, the purpose of the present study was to determine combined EMHG sensitivity and specificity of the test.

Methods: Results of IVCT of patients with previous fulminant MH and normal, low-risk subjects (controls) were collected from 22 centres of the EMHG.

Malignant-hyperthermia susceptibility is associated with a mutation of the alpha 1-subunit of the human dihydropyridine-sensitive L-type voltage-dependent calcium-channel receptor in skeletal muscle.

Malignant hyperthermia susceptibility (MHS) is characterized by genetic heterogeneity. However, except for the MHS1 locus, which corresponds to the skeletal muscle ryanodine receptor (RYR1) and for which several mutations have been described, no direct molecular evidence for a mutation in another gene has been reported so far. In this study we show that the CACNL1A3 gene encoding the alpha 1-subunit of the human skeletal muscle dihydropyridine-sensitive L-type voltage-dependent calcium channel (VDCC) represents a new MHS locus and is responsible for the disease in a large French family.

A genome wide search for susceptibility loci in three European malignant hyperthermia pedigrees.

Malignant hyperthermia (MH) is an autosomal dominant disorder which is potentially lethal in susceptible individuals on exposure to commonly used inhalational anaesthetics and depolarising muscle relaxants. Crises reflect the consequences of disturbed skeletal muscle calcium homeostasis. Susceptibility was first localised to chromosome 19q13.

Effects of preoperative intentional hemodilution on the extravasation rate of albumin and fluid.

Objective: To evaluate the effects of preoperative intentional hemodilution with 4% albumin solution on the extravasation rate of intravascular albumin and fluid in surgical patients.

Design: A prospective, randomized, clinical study.

Setting: University teaching hospital.

In vitro 31P-magnetic resonance spectroscopy of muscle extracts in malignant hyperthermia-susceptible patients.

Background: It was recently suggested that malignant hyperthermia-susceptible (MHS) patients could have an elevated peak of phosphodiesters in leg muscles using in vivo phosphorus magnetic resonance spectroscopy. In the current study, analysis of the phosphodiesters of muscle extracts of MHS and malignant hyperthermia-negative patients was performed using in vitro phosphorus magnetic resonance spectroscopy to chemically identify and to compare the muscle concentrations of water-soluble compounds between the two groups with respect to the muscle fiber type composition.

Methods: Perchloric acid extracts of the vastus medialis muscle of seven MHS patients and ten malignant hyperthermia-negative patients on the basis of the European malignant hyperthermia contracture test were subjected to in vitro phosphorus magnetic resonance spectroscopy carried out at 9.

[Prospective evaluation of a nuclear magnetic resonance score in the screening of malignant hyperthermia susceptibility. Initial results].

A prospective study for the noninvasive diagnosis of malignant hyperthermia (MH) susceptibility was conducted in 30 patients using 31P magnetic resonance spectroscopy (MRS). A score of MRS muscle abnormalities was determined before the in vitro contracture test. The patients were classified as MH susceptible or MH negative, according to an algorithm of MRS score values.

[Use of Diprivan in the elderly].

Propofol may be safely used in elderly patients provided that: hypovolaemia is corrected prior to procedure; a decrease in blood pressure of more than 25 per cent of the baseline value is treated with a sympathomimetic drug (e.g. ephedrine); bradycardia below 55 b.

Improved noninvasive diagnostic testing for malignant hyperthermia susceptibility from a combination of metabolites determined in vivo with 31P-magnetic resonance spectroscopy.

Background: Phosphorus magnetic resonance spectroscopy (31P-MRS) in vivo has been suggested recently as a possible noninvasive diagnostic test in malignant hyperthermia (MH) susceptibility. However, differences between protocols and also within subjects may have led to inconsistent MRS abnormalities reported during and after exercise. The aim of the current study was to detect discriminant abnormalities in the leg muscles using in vivo 31P-MRS during the rest period.

Muscular metabolism during oxygen supplementation in patients with chronic hypoxemia.

The effects of supplemental oxygen (O2) versus air on working calf muscle metabolism were studied in seven patients with stable chronic obstructive pulmonary disease (COPD) and chronic hypoxemia (PaO2 = 57 +/- 3 SE mm Hg) and seven age-matched control subjects. Oxygen and air were randomly administrated at 24-h intervals, and O2 flow rate was adjusted to correct hypoxemia (PaO2 = 87 +/- 4 mm Hg) in the COPD group. The relative concentrations of ATP, phosphocreatine (PCr), inorganic phosphate (Pi), phosphomonoesters (PME), and the intracellular pH (pHi) were determined with 31P magnetic resonance spectroscopy at rest, during a graded standardized and localized exercise protocol (360 active plantar flexions), and during recovery.

Comparative effects of halothane associated with verapamil and ischaemia on myocardial metabolism in isolated perfused rat hearts.

The association of verapamil with halothane causes ischaemic-like myocardial dysfunction. Using an isolated rat heart model perfused with a radiolabelled fatty acid (123I-labelled iodohexadecenoic acid) as a sensitive marker of ischaemia this study investigated whether or not this dysfunction is of ischaemic origin. Hearts were perfused with a control solution or with solutions containing either 1% of halothane or 150 ng ml-1 of verapamil or the association of 0.

Exertional heatstroke and muscle metabolism: an in vivo 31P-MRS study.

An impairment of muscle energy metabolism has been suggested as a predisposing factor for, as well as a consequence of exertional heatstroke (EHS). Thirteen young men were investigated 6 months after a well-documented EHS using 31Phosphorus Magnetic Resonance Spectroscopy (31P-MRS). The relative concentrations of ATP, phosphocreatine (PCr), inorganic phosphate (Pi), phosphomonoesters (PME), and the intracellular pH (pHi) were determined at rest, during a graded standardized exercise protocol (360 active plantar flexions) and during recovery.

[Pharmacokinetics of methohexital given by constant rate intravenous infusion].

The pharmacokinetic characteristics of a constant rate methohexitone infusion were studied in young ASA 1 patients undergoing maxillofacial surgery. They were randomly assigned to two groups; group M patients (n = 7) were given 9 mg.kg-1.

[Management of a patient with malignant hyperthermia susceptibility during anesthesia and daily living].

Death from malignant hyperthermia (MH) still occurs in France. However, anaesthesia of the MH susceptible (MhS) patient is quite possible without any more risk than for patients who are not MhS. Guidelines have been worked out: "trigger" drugs such as volatile anaesthetics (halothane, enflurane, isoflurane) and depolarizing muscle relaxants must be imperatively avoided; "non-trigger" drugs should be used, such as nitrous oxide, barbiturates, benzodiazepines, propofol, opiates, non-depolarizing muscle relaxants, amide or ester local anaesthetics at the usual doses without adrenaline.

[Registration of peranesthetic cases of malignant hyperthermia in France. An update].

Sixty-two suspected crises of anaesthetic malignant hyperthermia (MH) were collected between 1969 and 1988 by a retrospective inquiry which lasted four years. 33 patients (53%) died whilst 29 survived. 20 cases were confirmed to be MH, either directly or indirectly by way of muscle biopsy and halothane and caffeine contracture tests carried out according to the European MH group protocol by two laboratories.

[Comparison of the clinical effects of propofol and methohexital in induced abortion].

The clinical effects of propofol and methohexitone were compared in a group of 59 women undergoing abortion under general anaesthesia. At induction, the premedicated patients were given 2.5 mg .