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C Izard

Publications and source records attributed to C Izard.

8 recordsLinked to original sources

[Effect of the gas phase of cigarette smoke on the rate of sister chromatid exchanges in human lymphocytes in vitro].

A technique of differential staining of chromatids after BudR treatment enabled us to study the influence of the gas phase of cigarette smoke on human lymphocytes. We ascertained that the number of exchanges increased in proportion to the concentration of gas phase extant in the medium. Moreover, the base-line exchange rate was a little higher in smokers than in nonsmokers.

Chromatids

Acrolein.

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Acrolein

[Experimental study in rats to reduce carbon monoxide in the blood induced by cigarette smoke, by inhaling oxygen at atmospheric pressure].

When animals are exposed to cigarette smoke, the concentration of carbon monoxide in blood is rapidly increased, so that intensive inhalation tests cannot be carried out. A simple apparatus is described to expose Rats alternatively to cigarette smoke and to oxygen in order to reduce the concentration of carbon monoxide in the blood. This method makes it possible to increase the daily administration of smoke considerably; nevertheless, under such conditions, lung tumors were not observed.

Animals

[Genetic effects of the gaseous phase of cigarette smoke on Saccharomyces cerevisiae].

The gaseous phase of cigarette smoke is active on Saccharomyces cerevisiae. A toxic effect and several genetic alterations were observed. Mitotic segregants are induced and the cytoplasmic "petite" mutation is selected and induced. These effects vary according to the growth phase of the culture and to the brand of cigarettes tested. Stationary phase cells are more resistant than exponentially growing ones.

Cell Division

Genetic effects of formaldehyde in yeast. II. Influence of ploidly and of mutations affecting radiosensitivity on its lethal effect.

Haploid and diploid cells of Saccharomyces cerevisiae have the same sensitivity to formaldehyde, exponentially growing cells being more sensitive than stationary phase cells for both degrees of ploidy. Strains defective (rad 1-3) or with a reduced capacity (p-, cytoplasmic respiratory deficient mutants) in excision repair of ultraviolet-induced pyrimidine dimers show a greater sensitivity to formaldehyde than the corresponding wild type. A mutant defective in radiation-induced gene conversion (rec5) shows the same sensitivity as the wild-type strain. It appears that the excision-repair system plays an important role, especially in stationary phase cells, in repairing a fraction of formaldehyde-induced lesions.

DNA Repair

Genetic effects of formaldehyde in yeast. I. Influence of the growth stages on killing and recombination.

In random cultures, stationary phase cells of Saccharomyces cerevisiae are more resistant to killing induced by formaldehyde than are exponentially growing cells. It is shown that this compound induces intra- and intergenic recombination in this eucaryotic organism. In synchronized populations the lag and G1 phases demonstrate the higher resistance to both killing and induction of recombinants by formaldehyde whereas maximal sensitivity occurs during the end of G2 and/or the mitotic division. This pattern in contrast with that found after treatments by ionizing or ultraviolet radiations.

Formaldehyde

[Research into the electrophysiological effects of nicotine and their interpretation as arousal or sedation mechanisms (author's transl)].

The effect of nicotine on the nervous system during rapid smoking of two calibrated cigarettes was measured in twenty subjects: light, medium, heavy and non-smokers, across the changes of a number of electrophysiological variables and in different situations. Although some systems are consistently activated: with rapid EEG rhythms and EDG, others depending upon sub-grouping are activated or, conversely, are depressed or sedated (alpha and theta rhythm enhancement), the passive situations selected being opposed to the active situations. Attempts to explain this phenomenon seem to be dependent on the hypothesis that combination of environmental constraints and certain personalities or constitutions leads smokers who implicitly seek a sedative effect in smoking to administer themselves with a relatively low dose of nicotine by virtue of the varied modulations in their manner of smoking: the effective volume of puffs and the interval between puffs, whilst those who wish to stimulate themselves or arouse their cerebral cortex automatically take a considerably higher dose.

Arousal