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Biomedical subjects

A Astier

Publications and source records attributed to A Astier.

At least 91 records · Page 5Linked to original sources
PubMed1991

Elevated blood cyanide concentrations in victims of smoke inhalation.

BACKGROUND: The nature of the toxic gases that cause death from smoke inhalation is not known. In addition to carbon monoxide, hydrogen cyanide may be responsible, but its role is uncertain, because blood cyanide concentrations are often measured only long after exposure. METHODS: We measured cyanide concentrations in blood samples obtained at the scene of residential fires from 109 fire victims before they received any treatment. We compared the results with those in 114 persons with drug intoxication (40 subjects), carbon monoxide intoxication (29 subjects), or trauma (45 subjects). The metabolic effect of smoke inhalation was assessed by measuring plasma lactate at the time of admission to the hospital in 39 patients who did not have severe burns. RESULTS: The mean (+/-SD) blood cyanide concentrations in the 66 surviving fire victims (21.6 +/- 36.4 mumol per liter, P less than 0.001) and the 43 victims who died (116.4 +/- 89.6 mumol per liter, P less than 0.001) were significantly higher than those in the 114 control subjects (5.0 +/- 5.5 mumol per liter). Among the 43 victims who died, the blood cyanide concentrations were above 40 mumol per liter in 32 (74 percent), and above 100 mumol per liter in 20 of these (46 percent). There was a significant correlation between blood cyanide and carbon monoxide concentrations in the fire victims (P less than 0.001). Plasma lactate concentrations at the time of hospital admission correlated more closely with blood cyanide concentrations than with blood carbon monoxide concentrations. Plasma lactate concentrations above 10 mmol per liter were a sensitive indicator of cyanide intoxication, as defined by the presence of a blood cyanide concentration above 40 mumol per liter. CONCLUSIONS: Residential fires may cause cyanide poisoning. At the time of a patient's hospital admission, an elevated plasma lactate concentration is a useful indicator of cyanide toxicity in fire victims who do not have severe burns.

Adolescent↗
PubMed1990

Organic arsenic-induced Guillain-Barré-like syndrome due to melarsoprol: a clinical, electrophysiological, and pathological study.

A young woman suffering from sleeping sickness was treated with melarsoprol. Thirty-eight days after the first administration of this organo-arsenic compound, myalgias, distal paresthesias and rapidly progressive weakness developed in all four limbs. Electrophysiological studies were misleading for Guillain-Barré syndrome. Neuropathological data included massive distal wallerian degeneration in peripheral nerves and abnormalities in dorsal ganglia and spinal cord where vacuolation of anterior horn cells and axonal neurofilamentous masses were observed. Very high concentrations of arsenic were found in the spinal cord, contrasting with undetectable levels in peripheral nerves. Our findings are consistent with an arsenic neuronopathy manifested by initial proximal demyelination and delayed distal axonal damage. Renal and hepatic dysfunctions, which were implicated in the toxic arsenic accumulation, should be systematically detected before administration of melarsoprol. The diagnosis of Guillain-Barré syndrome must be considered with caution in patients treated with this compound.

Adult↗
PubMed1990

In vitro demonstration of the antidotal efficacy of hydroxocobalamin in cyanide poisoning.

The effects of sodium cyanide (1 mM) and the antidotal action of hydroxocobalamin (1 mM) were studied on rat cardiac papillary muscle. A 10-min period of exposure to cyanide induced a marked decrease in inotropy as shown by a decrease in the maximum unloaded shortening velocity (Vmax: 64 +/- 11% of precyanide values, p <0.01) and active isometric force (AF/s: 35 +/- 13%, p <0.01). The impairment of contraction-relaxation coupling under low load and the nearly complete disappearance of the load sensitivity of relaxation suggested a decrease in sarcoplasmic reticulum function. The proportional acceleration in isometric relaxation suggested a decrease in myofilament calcium sensitivity. There was a nearly complete recovery from cyanide poisoning after 5 min of exposure to hydroxocobalamin, whereas in a control group receiving cyanide alone, the mechanical parameters remained unchanged or were further impaired. The effects of hydroxocobalamin developed very quickly, beat to beat. The main toxic target of cyanide is brain and heart cytochrome oxidase, and brain damage appears only a few minutes after the onset of anoxia. Because hydroxocobalamin is a rapid and powerful antidote, it may be useful in the treatment of acute cyanide poisoning.

Journal Article↗
PubMed1990

[New valvular homografts. Prospects and limits of their viability. Report of 42 implantations].

The regain of interest in aortic homograft bioprostheses is related to the prospects of improved viability resulting from explanation from organ donors, preservation in rich tissue culture media, together with the progress made in techniques of cryopreservation. Viability studies examining morphology of electron microscopy and tests of tissue culture confirm this notion of longer viability. These properties raise hopes of satisfactory long-term results while acknowledging outstanding antigenic problems which require strict A-B-O system compatibility. The results of a preliminary series of 42 valve homografts implanted at Henri Mondor Hospital over the last 5 years are reported. Twenty-one bioprostheses were implanted on the right side in congenital heart disease with good results in every case. Twenty-one were implanted in the aortic position in children and show no signs of degeneration as yet. One poor result was related to a technical error in calibration. The rebirth of this technique raises certain hopes, especially in aortic valve replacement.

Adolescent↗
PubMed1990

[Viability of new valvular homografts. An evaluation at the Henri Mondor Hospital].

The renewed interest in valvular homograft is due to the new concept of their viability. This viability requires procurement from organ donors and preparation in rich tissue culture medium immediately prior to cryopreservation. This viability, confirmed by morphological tests especially electron microscopy, and by cell culture tests is the basis for satisfactory long-term results. Antigenic aspects justify rigorous respect of A-B-O compatibility. A preliminary clinical series of 35 valvular homografts (16 on the right side and 19 in the aortic position), implanted especially in children over the last five years at the Henri Mondor Hospital, is reported here, No tissue failures have been reported to date.

Aortic Valve↗
PubMed1988

Enhancement of adriamycin antitumor activity by its binding with an intracellular sustained-release form, polymethacrylate nanospheres, in U-937 cells.

We investigated the antitumor activity of Adriamycin on a monocytic-like cancer cell line U-937 after its binding on polymethacrylate nanospheres (diameter, 270-350 nm). Compared to free Adramycin (F-ADR), nanosphere-bound Adriamycin (B-ADR) exhibits a 3-fold enhancement of cytotoxicity, as determined by cell growth inhibition and DNA synthesis, after continuous exposure to 0.02 and 0.04 microgram/ml. The 90% growth inhibition concentration was 0.051 microgram/ml for F-ADR and was 0.018 microgram/ml for B-ADR (P less than 0.001). Furthermore, the nanosphere densities per cell play an important role since for the same drug concentration the higher the density increases, the better the activity is. Indeed, after 4 days of incubation in a medium containing 160 nanospheres at 0.5 fg/cell, the cell counts were 62.8 +/- 12.8% (SD) of the initial inoculum and they were only 16.1 +/- 0.1% after incubation in a medium containing 800 nanospheres at 0.1 fg/cell (P less than 0.001). A comparable enhancement of activity regarding the nanosphere densities was observed after a 24-h exposure to 0.02 and 0.05 microgram/ml. Short-term uptake studies showed that B-ADR accumulation was higher with B-ADR than with F-ADR. In addition, the efflux kinetics was modified. For cells exposed to F-ADR for 4 h, the efflux half-life was 23.7 +/- 7.7 h and the area to infinity under the efflux curve was 8.6 +/- 2.8 micrograms/mg protein x h-1. For cells exposed to B-ADR, the efflux half-life increased to 85.9 +/- 19.2 h and the area to infinity under the efflux curve to 29.6 +/- 6.6 micrograms/mg protein x h-1 (P less than 0.001). Electron transmission microscopy and previous findings have revealed that B-ADR was well internalized into cells. Our data support the hypothesis that B-ADR acts as an intracellular drug release complex after endocytosis. The findings regarding the number of nanospheres per cell and dose-effect relationships are consistent with mechanisms of drug actions extending to membrane domains.

Cell Compartmentation↗
PubMed1985

Oxalic acid level in bronchoalveolar lavage fluid from patients with invasive pulmonary aspergillosis.

Oxalic acid is a fermentation product of Aspergillus. We have measured the oxalic acid level in bronchoalveolar lavage fluids recovered from immunocompromised patients with and without invasive pulmonary aspergillosis. These levels were significantly higher in patients with invasive aspergillosis than in patients with pneumonitis of other causes. Thus, the determination of oxalic acid in bronchoalveolar lavage could be a presumptive argument for invasive aspergillosis until positive fungal cultures or histologic diagnosis; its potential value in monitoring the course of invasive pulmonary aspergillosis, particularly under treatment, has to be confirmed in more patients.

Adolescent↗
PubMed1983

[Pulmonary diffusion of gentamicin administered by the direct intravenous route].

Gentamicin diffusion in pulmonary parenchyma was studied in 10 adult patients with normal renal functions before undergoing thoracic surgery. This aminoside was given in a one time dose of 120 mg directly and by way of IV route in 10 min time; blood samples from peripheral and pulmonary sources were drawn at regular intervals between the 10 min period and the 8th hr; parenchymal samples were collected 1 and 2 hrs after drug administration. After separation of residual blood by centrifugation at high speed, the tissues are grinded and homogenized. The assay was performed with an immunological method using a fluorescent polarized detection system. Tissue levels were low in all the patients (0.5 to 2.75 micrograms/g of fresh tissue) and this in spite of the high level of blood collected throughout the administration protocol. As a rule, the relation between tissue/blood is lower than those discussed in literature concerning bronchial secretion. Beside this, the concentrations are similar in peripheral and pulmonary blood collected. Practical conclusions are drawn for therapeutic purpose.

Gentamicins↗
PubMed1983

[Pharmacokinetics of gentamicin in the decompensed alcoholic cirrhotic patient. Therapeutic consequences].

Aminoglycosides and in particular gentamicin are still largely used in the treatment of spontaneous bacterial peritonitis in the decompensed alcoholic cirrhotic patient. For that matter, we decided to study the various passage of gentamicin in the ascites after its administration through IM injection (80 mg in 6 patients and 120 mg in 6 other patients) and through IV injection (120 mg in 6 other patients). What could possibly be the best protocol to replace the daily intraperitoneal injections? We found out that no matter what the style of injection is, the peritoneal levels are only exceptionnaly higher than 3 mg/g at the highest peak period. These results brought us to analyze the passage of gentamicin in the blood when injected intraperitonealy (160 mg in 6 patients), and then to propose a therapeutic protocol combining on the first day, to the peritoneal injection a loading dose of an IP injection of 160 mg, the relay been taken over later with a peritoneal injection of 80 or 120 mg repeated 2 or 3 times daily. For each of the protocol the pharmacokinetic coefficients of gentamicin were calculated.

Bacterial Infections↗