Cel The aim of the research is to correlate the fibrogenicity and carcinogenicity of certain types of silica and coal with the presence of radical species in these materials; these radical species may permit electron exchange with the intracellular medium and may, for example, be involved in the reduction of oxygen to oxygenated radicals which are highly toxic through mechanisms related to oxidative stress. Determining how the amount of time between the fragmentation of the solid material and its inhalation affects the reactivity of the materials could have important implications in terms of prevention.The project is divided into three sections: 1) identifying the parameters which determine the appearance and disappearance of the radical species (S1, S10, S102, etc. in silica and "fossil radicals" in coal); the half-life will be determined in relation to the treatment conditions. 2) correlating the concentration of certain radical sites in silicas, and the concentration of fossil radicals in coal, with in-vitro and in-vivo experimantal data on their fibrogenic, transforming and carcinogenic potency. 3) comparing the results of these studies with the epidemiological data available. METHODS AND MEANS BY WHICH THE AIMS ARE TO BE ACHIEVEDThe radical species, their characteristics and their change time will be studied by electron paramagnetic resonance spectroscopy (EPR). The reactivity of these species towards oxygen will be tested in an aquous medium; the oxygenated radicals or other radical species formed by attack of oxygenated radicals on target molecules will be assayed by EPR using the technique of radical trapping. Fibrogenotocity will be studied (i) in vitro by tests employing macrophage and fibroblast cultures, and (ii) in vivo by intratracheal injection in rats. Carcinogenic effects will be investigated (i) in vitro by measuring transforming potency in hamster embryo cells, and (ii) in vivo by intratracheal injection in rats. The in-vitro and in-vivo experiments will be performed using the most representative samples identified in the physico-chemicals experiments. Program(-y) ECSC-MEDRES 5C - Fifth medical research programme (ECSC) "Protection of workers against risks arising from work in the coal and steel industries", 1988-1992 Temat(-y) Data not available Zaproszenie do składania wniosków Data not available System finansowania CSC - Cost-sharing contracts Koordynator Université P. et M. CURIE - C.N.R.S. Wkład UE Brak danych Adres 75252 PARIS Francja Zobacz na mapie Koszt całkowity Brak danych
