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1987
Journal Article
Title
Carcinogenic effects after combined exposure to PAH-containing emissions and other respiratory tract carcinogens.
Title Supplement
Abstract
Abstract
Rats, hamsters and mice were exposed to gasoline and Diesel engine exhaust (GE and DE) containig low concentration of polycyclicaromatic hydrocarbons (PAH) and to the PAH-rich mixture of pyrolized pitch and coal oven exhaust (PCE) 16-19 hrs/day, 5 days/week for a maximum of 2.5 years. Various carcinogens acting on the respiratory tract locally or systematically after noninhalative administration were used to investigate syn- and/or cocarcinogenic effects of the inhaled emissions. Nitrosamine (NA), PAH, urethane (U), crocidolite asbestos and glass fibers, calcium arsenate, cadmium chloride and oxide and nickel oxide were given subcutaneously (NA), intraperitoneally (U) or mostly intratracheally. Summarizing the results of these various combination treatment it appeared that the inhalation of DE and GE in most of the cases did not result in an enhancement of the tumor inducing effect of the carcinogenic substances administered additionally to the exhaust exposure; sometimes even an inhib itory effect was observed. Contrary to these findings, animals exposed to the PAH-rich emissions (PCE) and treated at the same time with other respiratory tract carcinogens showed syncarcinogenic (potentiating) or at least additive carcinogenic effects; e.g. with asbestos fibers or dibenz(a,h) anthracene in rats and with benzo(a)pyrene or diethylnitrosamine in hamsters.