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Biomedical subjects

C Michel

Publications and source records attributed to C Michel.

At least 325 records · Page 18Linked to original sources
PubMed1986

[Renovascular hypertension with renal failure: value of renal revascularization].

The purpose of this work was to determine the effects of renal revascularization on blood pressure and renal function in 9 patients with arterial stenosis involving both kidneys (7) or a solitary kidney (2). There were five women and four men with a mean (SD) age for 64.5 +/- 7 years. The duration of hypertension ranged from 2 to 28 years (mean = 12 +/- 8). Blood pressure ranged from 210/100 to 260/150 mmHg, despite the use of three or more antihypertensive agents in 7 cases. The serum creatinine level, on presentation, ranged from 160 to 265 mumol/l (mean = 198 +/- 30 mumol/l). Intravenous pyelograms were not suggestive of renovascular disease in 4 of 7 cases. Digital angiography or arteriography demonstrated severe stenosis of the artery of the solitary kidney in 2 patients, severe bilateral atherosclerotic disease in 7 patients, three of them had complete occlusion of a main renal artery. During hospitalization, therapy with captopril (5 patients) or minoxidil (1 patient) lowered blood pressure in 3 cases, but induced a marked increase in serum creatinine level in 4 cases. In two patients, medically treated, severe and rapidly progressive impairment of renal function was observed. The seven remaining patients underwent surgical revascularization (two after unfructuous percutaneous transluminal angioplasty). One died 45 days later. Blood pressure control with diastolic blood pressure of 100 mmHg or less was achieved in the other six, although each patient continued to require antihypertensive medication (bitherapy: 2, monotherapy: 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Pharmacokinetics of teniposide (VM 26) after IV administration in serum and malignant ascites of patients with ovarian carcinoma.

Nine patients with ovarian carcinoma and malignant ascites treated with IV teniposide chemotherapy (30 mg/m2/30 min) entered this study. Plasma and peritoneal fluid levels were measured by an HPLC method with electrochemical detection. Plasma decay kinetics followed a triexponential function. A high variability of drug diffusion in ascites was noticed. Peak concentrations in ascites ranged from 1.6% to 20.5% of serum peak concentration. The concentration in peritoneal fluid reached a maximum level 6 h after the infusion ended. Teniposide was less slowly eliminated from ascites than from serum. The exposure of the inflammatory peritoneal fluid to the drug expressed by area under the concentration-time curve (AUC) was also subject to significant interindividual variation, ranging from 223 to 2332 micrograms/ml X min. However, the peritoneal AUC was correlated with serum AUC and with the systemic clearance of the drug. A significant relationship between gamma glutamyltranspeptidase and both systemic clearance and either the serum or the peritoneal AUC was found, suggesting that liver plays a role in drug disposition.

Aged↗
PubMed1985

Models to predict operational loads of flight schedules.

Several concepts have been presented in the literature which have the potential to predict the operational load on aircrews during long-distance flights. They are briefly described and applied to a flight duty pattern actually scheduled for an airline route. For each model relative and absolute difficulty grades for the different segments of the pattern are evaluated and compared. Relative ranking results in an excellent agreement between the various models. Absolute classification into "normal," "heavy," and "definitely severe" segments reveals less conformity. From our observations on this route, it is concluded that the index of Mohler's model reflects the most realistic load estimates. Finally, a new approach is introduced which considers duty period, night flying, number of transits, preceding layover time, and preceding time-zone transitions as those elements constituting a computable and essential part of the operational load.

Aerospace Medicine↗
PubMed1983

Cellular damage and recovery of the early developing mouse eye following low dose irradiation. II. X-rays on day 9 of gestation.

Mouse embryos on day 9 of gestation were exposed in utero to 90 rad X-rays. At different time intervals after treatment the eye primordia were examined for cell death. The irradiation caused an altered necrosis pattern compared with day 8, and massive cell killing during a limited time period. The rapid recovery from the pronounced damage points to a high restitution efficiency of the involved tissue.

Animals↗
PubMed1983

Combined application of misonidazole and piotron pions on mouse embryos.

Mouse embryos on day 8 of gestation were irradiated with negative pions (12.5-100 rad) or 200 kV X-rays (12.5-150 rad). Misonidazole (MISO), a hypoxic cell radiosensitizer, was applied 30 min before exposure. On day 13 the fetuses were examined for lethality, growth retardation and malformation. No significant embryolethal effects were observed after irradiation alone in the dose range of 12.5-100 rad (X-rays or pions). However, MISO alone and in combination with radiation led to high rates of lethality. The frequency of growth retardation was significantly increased at 100 rad and in combined treatments at low radiation doses. MISO and irradiation with 50 rad and more induced complex damages consisting of multiple and severe malformations and growth retardation. The relative biological effectiveness (RBE) for teratogenic effects was 1.6. In conclusion, the combined application of MISO and radiation of different LET revealed a strong enhancing action compared to single treatments. The extent of enhancement depends on both radiation quality and dose.

Abnormalities, Drug-Induced↗
PubMed1982

Radical intermediates involved in the bleaching of the carotenoid crocin. Hydroxyl radicals, superoxide anions and hydrated electrons.

The participation of the primary radicals in the bleaching of aqueous solutions of the carotenoid crocin by ionizing radiation was investigated, employing both X-radiolysis and pulse radiolysis. The pulse-radiolytic data demonstrated a very rapid diffusion-controlled attack by both hydroxyl radicals (.OH) and hydrated electrons (eaq-), while superoxide anions (O2-) did not react at all. The site of the initial reaction of these radicals was not limited to the polyene chromophore. Slower secondary reactions involving crocin alkyl or peroxy radicals contribute mainly to the overall bleaching, in particular during steady-state irradiation.

Carotenoids↗
PubMed1982

[Effect of temperature on the results of the antibiotic sensitivity test performed by the diffusion method in fish pathology].

The sensitivity disk method is currently used in fish pathology to assess the efficacy of antimicrobial drugs. However, it is generally performed at temperatures lower than 37 degrees C, at which standard procedures were recommended by WHO. In order to check up the reliability of the results, selected strains and antibiotic substances were at once studied at 37 degrees C and 22 degrees C. In the last case, two readings of the zones of inhibition were done, after 24 and 48 h of incubation. Minimal inhibitory concentrations (MIC) had been determined using an agar-plate dilution method. Each association drug-bacterial strain provided three samplings of 30 measures which were compared by variance analysis and mean comparison tests. Variances did not differ, except with chloramphenicol and tetracyclines. But the mean values of the diameters significantly differed according to the incubation temperature. The variations could reach 7 to 8 mm, in any way. So, it appears that the disk method fails to allow any quantitative interpretation when performed at 22 degrees C. Consequences in diagnostic of fish diseases are stressed.

Animals↗