PubMed Health⌕ Search

Biomedical subjects

B Vallet

Publications and source records attributed to B Vallet.

14 recordsLinked to original sources
PubMed1992

Myasthenia gravis and steroid-induced myopathy of the respiratory muscles.

OBJECTIVE: We report a case of corticosteroid-induced myopathy with involvement of respiratory muscles observed in a myasthenic patient. PATIENT: A 37-years-old woman, under corticosteroid treatment for two years for typical myasthenia gravis was admitted to ICU for acute myasthenic respiratory failure. Weaning from mechanical ventilation remained impossible despite 4 plasma exchanges and azathioprine. The patient exhibited a progressive 12 kg weight loss with muscular weakness and atrophy. MEASUREMENTS AND RESULTS: Peripheral and diaphragmatic electromyography as well as histological study were consistent with a steroid-induced myopathy. Discontinuation of corticosteroid treatment was followed by a rapid weight gain with general improvement and allowed weaning from mechanical ventilation with a complete recovery. CONCLUSION: This case provides evidence that corticosteroid-induced myopathy may be observed in myasthenia gravis and may involve the respiratory muscles as well as the peripheral musculature.

Adrenal Cortex Hormones↗
PubMed1992

[Cardiac herniation and sub-herniation. Complication of intrapericardial pneumonectomy].

Two cases are reported of cardiac herniation complicating intrapericardial pneumonectomy in the early postoperative period. Both patients had a radical pneumonectomy for right-sided bronchial carcinoma invading, in one patient, the carina and the superior vena cava. The pericardial defect, made necessary by the surgical procedure, had not been closed in either patient. About two hours after the end of surgery, both patients, lying supine, developed a state of shock, with tachycardia and arterial hypotension. The diagnosis of cardiac herniation was made in both cases on the chest film. Placing the patient on his left side was only partly efficient in one patient, slowing the heart rate from 160 b.min-1 to 120 b.min-1 and increasing the systolic blood pressure (from 60 mmHg to 80 mmHg). Both patients therefore required to be operated on again. In one patient, the heart had completely herniated through the pericardial defect, and had turned to the right side about the vena caval axis; in the other patient, partly improved by being turned to his left, the heart had returned to its normal position. The pericardial defects were closed in both cases with a strip of dura mater previously treated with 2 (ethyl-mercurithiol-5-benzoxazol) carboxylic acid. The immediate postoperative course was uneventful. Unexpected symptoms and sign occurring in the early postoperative period after intrapericardial pneumonectomy must imperatively lead to carrying out a chest X-ray.

Adult↗
PubMed1992

[Relation between oxygen delivery and consumption during septic states. Value of an early dobutamine test].

From previous studies it has been hypothesized that multiple organ failure and high level of mortality, seen in critically ill septic patients, may be due to defective oxygen extraction and tissue hypoxia occurring early in the course of sepsis. Oxygen flux test has been proposed as a method of revealing an occult oxygen debt. We used a one hour dobutamine infusion test, in septic patients, without increase in blood lactate. Fifty patients with sepsis syndrome entered a multicentric prospective study. After fluid loading to increase pulmonary artery occlusion pressure (Paop) to a minimum value of 10 mmHg, all the patients were given 10 mcg/kg.min of dobutamine for one hour. Hemodynamic and metabolic variables were recorded before, HO, and after the test, H1 (cardiac index, Paop, oxygen deliver, DO2, and consumption, VO2, oxygen extraction ratio, (OER), blood lactate). The dobutamine test allowed to identify responders (R) who increased VO2 by more than 15% and non-responders. R and NR differed significantly in mortality (8.5% vs 44.4%). The test has a good predictive value for surviving. Without respect of the result of the test, the patients were randomized in two groups. The group D+ was given conventional therapy and dobutamine at the same rate of infusion for 9 consecutive days and the D- group received only conventional therapy. The RD+ patients improved more rapidly when compared with RD-, NRD+, NRD-. We concluded that a one hour dobutamine test is able to identify R and NR critically ill septic patients. The response is associated with significant difference in outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Infections↗
PubMed1991

[Dobutamine: mechanisms of action and use in acute cardiovascular pathology].

High levels of circulating catecholamines associated with heart failure down-regulate cardiac beta-receptors, with a more pronounced effect on beta-1 receptors, leading to impaired inotropic effect. The use of exogenous inotropic agents is therefore a logical therapeutic approach in heart failure. Dobutamine is a synthetic catecholamine that acts on alpha-1, beta-1 and beta-2 adrenergic receptors. In the heart, the stimulation of these receptors produces a relatively strong, additive inotropic effect and a relatively weak chronotropic effect. In the vasculature, alpha-1 agonist activity (vasoconstriction) balances the beta-2 agonist effect (vasodilatation). In clinical use, dobutamine has a rapid onset of action and a short half-life. It increases myocardial contractility, while the reflex reduction in sympathetic tone, in response to augmentation of stroke volume, leads to a decrease in total peripheral resistance. The expected hemodynamic effects are an increase in cardiac output and a decrease in systemic vascular resistance without significant change in arterial pressure or heart rate. In acute cardiac failure state with elevated afterload pressures, resulting from myocardial dysfunction, dobutamine therapy remains, nowadays, the reference.

Acute Disease↗
PubMed1989

[Anaphylactic shock caused by fluorescein].

Authors report one case of death caused by anaphylactic collapsus after a fluorescein angiography. They make a review of all the complications described and particularly insist about the anaphylactic reactions. They conclude on the modalities of treatment.

Aged↗
PubMed1979

Purification and characterization of bovine cardiac calmodulin-dependent myosin light chain kinase.

Myosin light chain kinase, which is located primarily in the soluble fraction of bovine myocardium, has been isolated and purified approximately 1200-fold with 16% yield by a three-step procedure. The approximate content of soluble myosin light chain kinase in heart is calculated to be 0.63 microM. The isolated kinase is active only as a ternary complex consisting of the kinase, calmodulin, and Ca2+; the apparent Kd for calmodulin is 1.3 nM. The enzyme also exhibits a requirement for Mg2+ ions. Myosin light chain kinase is a monomeric enzyme with Mr = 85,000. The enzyme exhibits a Km for ATP of 175 microM, and a K0.5 for the regulatory light chain of cardiac myosin of 21 microM. The optimum pH is 8.1. Kinase activity is specific for the regulatory light chain of myosin. The specific activity of the isolated enzyme (30 nmol 32P/min/mg of protein) is considerably less than and corresponding values reported for the skeletal and smooth muscle light chain kinases. This is probably due to proteolysis during extraction of the myocardium, a phenomenon which has, as yet, proven impossible to eliminate. In contrast to the smooth muscle enzyme (Adelstein, R.S., Conti, M.A., Hathaway, D.R., and Klee, C.B. (1978) J. Biol. Chem. 253, 8347-8350), the cardiac kinase is not phosphorylated by the catalytic subunit of cAMP-dependent protein kinase.

Animals↗
PubMed1975

2,3-2, 3-.

Erythrocityc variations of glycolytic intermediates and 2,3-DPG levels in rabbits performing strenuous exercise under hypoxic conditions are correlated with blood pH variations. The hypoxia alone is not able to induce directly an increase of erythrocytic 2,3-DPG level which would facilitate tissue oxygenation.

Animals↗