Applying theoretical premises of binary toxicity mathematical modeling to combined impacts of chemical plus physical agents (A case study of moderate subchronic exposures to fluoride and static magnetic field).

Sodium fluoride solution was injected i.p. to rats at a dose equivalent to 0.1 LD50 three times a week up to 18 injections. Two thirds of these rats and of the sham-injected ones were exposed to the whole body impact of a 25 mT static magnetic field for 2 or 4 h a day, 5 times a week. For mathematical analysis of the effects they produced in combination, we used a response surface model. This analysis demonstrated that (like in combined toxicity) the combined adverse action of a chemical plus a physical agent was characterized by a diversity of types depending not only on particular effects these types were assessed for but on their level as well. From this point of view, the indices for which at least one statistically significant effect was observed could be classified as identifying (1) single-factor action; (2) additivity; (3) synergism; (4) antagonism (both subadditive unidirectional action and all variants of contradirectional action). Although the classes (2) and (3) taken together encompass a smaller part of the indices, the biological importance of some of them renders the combination of agents studied as posing a higher health risk than that associated with each them acting alone.

Toxicity of monazite particulates and its attenuation with a complex of bio-protectors.

BACKGROUND: Workers employed on mining, processing and storage of monazite are at risk of exposure to dust with expected adverse health effects. OBJECTIVES: To study the adverse health effects of monazite particles in experiments on rats and to test the possibility of attenuating these effects. METHODS: Outbred white rats were injected intratracheally with a suspension of ground monazite concentrate (MC) in order to investigate the cellular response of the lower airways 24 hours later and the organism's status 6 months after the injection. The bio-protective complex (BPC) tested in these experiments consisted of glutamate, an iodine preparation, methionine, a polyvitamin-polymineral composition, and/or "Eicosavitol" (fish oil preparation rich in PUFA, predominantly of the omega 3-group). Bio-protectors were administered together with the rat food and drink daily for one month before the MC injection in the short-term experiment, or over 6 months after such injection in the long-term experiment. RESULTS: MC induced manifestations of its cytotoxicity, fibrogenicity and systemic toxicity as well as genotoxicity. The tested BPC attenuated virtually all these effects. Although a similar protective potential of "Eicosavitol" against almost all of them was lower compared with that of BPC, combining BPC with "Eicosavitol" provided, as a rule, the greatest protective effect. CONCLUSION: It may be assumed that the many-sided adverse effects of MC on the organism is due, at least partially, to the presence in its composition of not only rare earth elements but also of natural radioisotopes of the thorium and uranium families. The combination of the bio-protectors tested was highly effective and may be recommended for administering in periodic preventive programmes to exposed workers.