A Demonstration of the Radiation Hormesis Concept

Journal/Book: Z. Phys. Med. Baln. Med. Klim. (Sonderheft 2) 19 (1990) 12-18. 1990;

Abstract: Laboratoire de Radiobiologie et Biologie Spatiale Faculté de Médecine Toulouse France I. Introduction The effects of high doses of radiation have been extensively studied. In contrast very few experimental works have been done on the effects of very low doses. In our laboratory we have been working for many years on the influence of background radiation and chronic gamma irradiation at a very low dose rate. In this paper we will summarize the main results of investigations carried out at the cellular level and on the immune system of mice. Our results are in favour of the radiation hormesis concept (LUCKEY 1982) and demonstrate that the biological effects of very low doses of ionizing radiation can be different from those of high doses. II. Investigations performed on eucaryotic cells Effects of background and very low doses were investigated in paramecia. Paramecium caudatum and Paramecium tetraurelia are single cell free swimming organisms living in fresh water. Background and chronic gamma irradiation stimulate their proliferation. Indeed: -the cell growth rate is reduced when paramecia are cultivated in a shielding device i.e. in a lead chamber 5 or 10 cm thick (o. Fig. 1). - the growth inhibition disappears when the shielded cultures are simultaneously irradiated by a 232Th source giving a dose rate of 7 mGy/y close to background (o. Fig. 2); - an inhibition of cell proliferation occurs when paramecia are cultivated in a cave at the underground laboratory of Centre National de la Recherche Scientifique located at MOULIS in the Pyrénées Mountains under 200 m of rocks. The inhibition is more obvious when cultures are shielded by 5 cm of Pb against the radioactivity of cave walls and disappears when paramecia cultivated in the cave are exposed to 60Co gamma irradiation at a dose rate of 4 mGy/y (o. Fig. 3);... ___MH

Keyword(s): Radiation Hormesis Concept

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