Influence on Cell Proliferation of Background Radiation Or Exposure to Very Low, Chronic Gamma Radiation

Abstract

Investigations carried out on the protozoan Paramecium tetraurelia and the cyanobacteria Synechococcus lividus, which were shielded against background radiation or exposed to very low doses of gamma radiation, demonstrated that radiation can stimulate the proliferation of these two single-cell organisms. Radiation hormesis depends on internal factors (age of starting cells) and external factors (lighting conditions). The stimulatory effect occurred only in a limited range of doses and disappeared for dose rates higher than 50 mGy/y.

Documented optimum and threshold for ionising radiation

“…They used natural (radioactive) potassium in the media. Planel et al (1987) led the French team at Toulouse to explore the effects of subambient levels of ionising radiation. Under full illumination, the blue-green alga (#3 , Table 1) grew at a reduced rate when grown in lead boxes.…”

“…They ignored radon, used natural (radioactive) KCl in their media and took no precautions to reduce radon. Kuzin and Krymskya (1994) 10 mouse 42 growth <50 100 Kuzin and Krymskya (1994) Notes: 1 Escherichia coli -these experiments were performed in ambient levels of ionising radiation at Argonne National Laboratory (ANL) with non-radioactive potassium, 39 K, in the medium (Luckey, 1983) 2 Mastigocladus laminosus -experiments #2, #4 and #8 were performed within a 10 cm steel box with light in a room at the middle of the Simlon Tunnel, about 8000 feet below Mt Leone-Massive, France (Eugaster, 1964) 3 Synechococcus lividus -when housed in a 10 cm lead box with light in a surface laboratory, the level of ionising radiation was only 17% that of the control (Planel et al, 1987) 4 Hordeum bonus -the conditions were those described in #2 (Eugster, 1964) 5 Paramecium tetraurelia -conditions were as in #3, without light and with bacteria as a food source (Planel et al, 1987) 6 Paramecium bursaria -cultures were maintained in a surface laboratory within a 10 cm lead box inside an incubator (Luckey et al,. 1978).…”

Germination and cytological aspects of <i>Dolichos lablab</i> L. exposed to gamma radiation

“…The beneficial effects of low doses of gamma irradiation accomplished with the phenomenon of Hormesis (Luckey 1980;Sagan 1987;Planel et al 1987;Korystov and Narimanov 1997).…”

Réflexions sur la radiocancérogenèse

“…Dans ce second cas, qui est le plus important, je serais enclin à qualifier de bénéfique tout effet qui confère un avantage sélectif à cette population. Il convient alors de prendre en considération les travaux poursuivis à Toulouse depuis une quinzaine d'années par Hubert PLANEL et son équipe [14]. Selon leurs résultats, d'abord contestés mais aujourd'hui admis, les faibles doses administrées à faible doses administrées à faible débit par l'irradiation naturelle, augmentent le taux de croissance de populations de micro-organismes monocellulaires (paramécies notamment).…”