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G Chevalier

Publications and source records attributed to G Chevalier.

103 records · Page 6Linked to original sources
PubMedDate not supplied

Distribution study of radioactivity in rats after oral administration of the lipido/sterolic extract of Serenoa repens (Permixon) supplemented with [1-14C]-lauric acid, [1-14C]-oleic acid or [4-14C]-beta-sitosterol.

The study carried out on rats given orally the n-hexane lipido/sterolic extract of Serenoa repens (LSESR), supplemented with [14C]-labelled oleic or lauric acids or beta-sitosterol, demonstrated that radioactivity uptake in prostatic tissues shows the highest level in the case of administration of LSESR supplemented with [14C]-labelled oleic acid. This was clearly demonstrated on a rat with an induced fibro-muscular hyperplasia of the prostate and by quantitative measurements of radioactivity. Ratios of radioactivity in tissues compared to plasma show an uptake of radioactivity greater in prostate as compared to other genital organs, i.e. the seminal vesicles or to other organs such as liver.

Administration, Oral↗
PubMedDate not supplied

Inability of chrysotile asbestos fibers to modulate the 2-acetylaminofluorene-induced UDS in primary cultures of rat hepatocytes.

There is now growing evidence that asbestos fibers could act in association with genotoxic compounds, either as cocarcinogens or promoters, in the process of carcinogenesis. The hepatocyte/UDS assay system has been taken to advantage to investigate the capacity of fibers to modulate the effects of genotoxic compounds on the cell, as we previously demonstrated the hepatocytes can engage in phagocytosis of chrysotile fibers. Measurement of UDS was performed by a biochemical procedure involving liquid scintillation counting (LSC) of a purified DNA fraction as well as by radioautography. Both LSC and radioautography revealed that chrysotile asbestos fibers UICC B at concentrations up to 100 micrograms/ml do not elicit UDS, whereas 2-acetylaminofluorene (2-AAF) at low concentrations (0.05-0.625 micrograms/ml) significantly induces it in parallel positive controls. In an attempt to test the cocarcinogen hypothesis, cultures of hepatocytes were simultaneously exposed for 20 h to 2-AAF (0.05 and 0.25 micrograms/ml) and asbestos fibers (1 and 10 micrograms/ml) given as simple mixtures. It was found that the 2-AAF-induced UDS activity was the same whether fibers were present or not. This was observed with both UDS evaluation procedures at all concentration combinations selected. An analysis of variance applied to the data collected from several experiments confirmed that there was no significant 2-AAF-fiber interaction. Our data suggest the absence of intrinsic genotoxic properties for chrysotile fibers. They also indicate that the modulation of the cellular response to genotoxic agents by asbestos fibers is not detected under our test conditions and may require longer-term exposures to be expressed.

2-Acetylaminofluorene↗
PubMedDate not supplied

Interactions of asbestos fibers with hepatocytes in vitro: an ultrastructural study.

Cultures of rat hepatocytes have been used to study the interaction of chrysotile asbestos fibers with epithelial cells. The hepatocytes were incubated for 20 h with chrysotile asbestos (UICC B and a preparation of short fibers: 90% less than 2 micron) at concentrations of 1 or 10 micrograms/ml. Morphologic studies were then performed by means of transmission electron microscopy. Fibers were incorporated into plasma membrane invaginations, cytoplasmic vacuoles and phagolysosomes. These observations demonstrate that rat hepatocytes can engage in phagocytosis of chrysotile fibers. The results are compared to those previously obtained with mesothelial cells and tracheobronchial epithelium, exposed to asbestos in vitro. The advantages of the hepatocyte model to investigate the effects on cells of the association of asbestos fibers with genotoxic agents in relation to carcinogenesis are discussed.

Animals↗
PubMedDate not supplied

Age-related variations of lipid peroxidation in cadmium-treated rats.

Under specific conditions, Cd can induce a prooxidant state in biological systems resulting in the peroxidation of the polyunsaturated fatty acids. We investigated in vivo this phenomenon in major target organs of Long Evans rats (12- and 36-week-old), 24 hours after being injected i.p. with a range of cadmium chloride doses (0.00, 0.05, 0.25, 1.0 or 2.5 mg Cd/kg). The measurements of the thiobarbituric acid reactive substances demonstrated that the lungs showed the highest Cd-induced LPO in the 12-week-old rats even if the liver and kidneys accumulated the greatest amounts of Cd. Cd-induced LPO as measured by TBARS assay in the 36-week-old groups was, in all organs, less pronounced even if the control levels were higher for these groups. The reasons for this age-dependent differences are not clear. Some components of the antioxidant defense system were differently modulated as a function of age. However, it is not certain whether these changes have a causative role in the induction of LPO following Cd exposure.

Age Factors↗
PubMedDate not supplied

A new method for the measurement of tremor at rest.

This paper establishes a standard method for measuring human tremor. The electronic instrument described is an application of this method. It solves the need for an effective and simple tremor-measuring instrument fit for wide distribution. This instrument consists of a piezoelectric accelerometer connected to an electronic circuit and to an LCD display. The signal is also analysed by a computer after accelerometer analogic/digital conversion in order to test the method. The tremor of 1079 healthy subjects was studied. Spectral analysis showed frequency peaks between 5.85 and 8.80 Hz. Chronic cigarette-smoking and coffee drinking did not modify the tremor as compared with controls. Relaxation session decreased tremor significantly in healthy subjects (P less than 0.01). This new tremor-measuring method opens new horizons in the understanding of physiological and pathological tremor, stress, anxiety and in the means to avoid or compensate them.

Adult↗
PubMedDate not supplied

[Polymorphic secretory antigens (WZ) of the human adult and fetal colon].

The present paper concerns further data about the WZ polymorphic antigens of the human colon. A population study conducted with the immunofluorescence technique on rectal biopsies from 150 subjects, confirmed the frequency of the three phenotypes : W+Z (0.65), W-Z+ (0;25), W-Z- (0.10). The same three phenotypes were observed with the immunofluorescence technique in the colon goblet cells of 20 foetuses ranging in ages from 20 to 36 weeks. In these foetuses a comparative study of the WZ and ABH antigens along the length of the gastrointestinal tract showed the same reverse distribution of the two kinds of antigens as previusly reported in the adult. The comparison of the inhibition activity of adult or foetal colon mucosa extracts in a radioimmunoassay test showed that the WZ antigens are similarly present in heated water, phenolalcohol, and perchloric acid extracts. The WZ antigens are present in the meconium.

Colon↗