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Biomedical subjects

C Michel

Publications and source records attributed to C Michel.

At least 361 records · Page 20Linked to original sources
PubMed1977

Radiation damage in mouse embryos exposed to 1 rad x-rays or negative pions.

Pregnant mice of two different strains (F/A and NMRI) were exposed to 1 rad of whole-body pion- or X-irradiation at day 8 of gestation. Lucanthone (Miracil D), a known radiosensitizer in various biological systems, was applicated 30 min before irradiation. Five days after treatment the fetuses were observed for developmental anomalies. In both strains of mice it was found that the radiation dose as low as 1 rad results in a significant increase in the rate of abnormal fetuses compared to nonirradiated, but restrained fetuses. Comparing the effectiveness of negative pions (peak irradiation) with X-rays for teratogenic effects, the RBE was between 1.7 and 1.9. The application of Lucanthone increased the number of damaged fetuses and led to various degrees of sensitization depending on the mouse strain and dosage used. Differences between the strains as regards the frequency of damages are explained by different development stages at the time of treatment.

Animals↗
PubMed1977

Modification of Cunningham's method for the detection of proteases in tissue sections.

A modification of Cunningham's method to show the protease activity in fresh tissue sections on gelatin film is proposed. The diazotization of the gelatin film in two successive baths of Fast blue B salt sharply increases the colour intensity of the film, improving the contrast between the intact zones and the enzymatic lysis zones of the substrate. The various washings of the stained film have been simplified. After incubation, the histological staining of the sections by solid nuclear red is an improvement over the much more tricky Feulgen reaction, combined with PAS, used by Cunningham.

Animals↗
PubMed1977

Effects of low-dose irradiation with x-rays and pi-mesons on embryos of two different mouse strains.

The effects of two different kinds of radiation (X-rays and negative pions) on embryonic development of mice was examined. The application of a known radiosensitizer (lucanthone) combined with 13.5 rd whole-body irradiation on day 8 of gestation showed enhanced teratogenic action compared to treatment with each of the agents alone. The extent of intensification varied both with mouse strain and treatment, indicating possible differences in repair capacity and LET-dependency of sensitization effects. Strain differences were found in the incidence and type of chemical and radiation-induced malformations, which may be explained by different developmental stages at the time of treatment.

Animals↗
PubMed1975

Pulse-radiolytic investigations of catechols and catecholamines. I. Adrenaline and adrenochrome.

Adrenaline (epinephrine), adrenochrome and C4-substituted catechol model compounds were pulse-irradiated in aqueous neutral and alkaline solutions. Transient spectra are reported after oxidizing adrenaline and reducing adrenochrome. All species appearing during 20 msec interval after the pulse have been identified: the OH adduct with an absorption maximum at 300-310 nm, the semiquinone (at 245 nm), and adrenaline quinone (at 340 nm). The reaction of superoxide anions (O2-) with adrenaline was less efficient, compared with OH radicals. A novel oxidation product, derived from the semiquinone and O2-, has been identified as the 4-hydroxy-3,6-dioxo derivate. The pulse-radiolytic reduction of adrenochrome by hydrated electrons (eaq-) yielded the semiquinone of adrenochrome (absorbing at 470 nm), which subsequently decays by a second-order process. The dismutation products leuco-adrenochrome (absorbing at 300 nm, pH 9-8) and the adrenochrome tautomer (absorbing at 375 nm) are unstable, forming 5,6-dihydro-N-methyl indole and regenerating adrenochrome.

Adrenochrome↗
PubMed1975

["Pearl necklace" arteries in vascular nephropathy with acute renal insufficiency (author's transl)].

The authors study "pearl necklace" arteries (PNA) in vascular nephropathies with acute renal insufficiency. Seventeen patients underwent aortography complemented by selective angiography of the renal, superior mesenteric and coeliac arteries to seek renal and extra-renal lesions. PNA were discovered remarkably often (mesenteric branches and renal arteries above all). Three types of PNA are described. PNA do not occur in acute angitis (3 cases, 2 PAN). They almost invariably occur in ATN (7 cases) and may be seen in ASMN (7 cases), which eliminates any diagnostic value in the distinction of these two types of acute anuric vascular nephropathy. The functional nature of PNA is open to discussion, but it appears that in the long term histological changes and functional modifications in the involved areas may occur. The role of hypertension and vaso-active substances in the aetiology of PNA is discussed.

Acute Kidney Injury↗