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Biomedical subjects

S Doubal

Publications and source records attributed to S Doubal.

4 recordsLinked to original sources
PubMed1990

Influence of aging rate change on mortality curves.

One of the key problems of experimental gerontology is that there is usually some degree of uncertainty in the correct interpretation of experimental or observational data. Namely, it is difficult to decide whether the changes in life span, mortality rate or physiological state are due to the changes in biological age of organisms or to other causes. The analysis of mortality curves, suggested here, can reveal relevant information and may also contribute to discussions on the nature of the aging process. Our models are designed to provide a mathematical and system-theoretical basis to this methodology. The conditions of the validity of the models are simple and their relevancy to reality is discussed. Further, the reliability model suggests an explanation of apparent discrepancy between constant relative decline in physiological functions, often observed during aging, and Gompertzian growth of mortality.

Aging↗
PubMed1989

[Stimulatory effects of small doses of mutagens].

Small radiation doses stimulate the organism. This so-called hormetic effect was first described in the fifties, however, only in recent years it has been accepted. According to data in the literature the hormetic effect comprises stimulation of the immune system, a general increase of the resistance of the organism, a reduced risk of cancer and in model organisms a protraction of the median life span was observed. Positive effects of small doses were observed in experiments with cell and tissue cultures of animal and plant origin. A prolongation of the median and maximal life span in Drosophilae was also observed. There are indications that the hormetic effect could be due to the action of chemical mutagens. Attempts to explain this phenomenon are as a rule based on the finding that the activity of reparative DNA systems is substantially increased in case of a disorder of newly synthetized DNA. This reduction is triggered by a feedback reaction in the regulatory chain of synthesis of reparative enzymes. In the literature experiments were already described on the application of the hormetic phenomenon in therapy. Wider use calls, however, for systematic research. The perspective seem promising.

Animals↗