polonium and Cocarcinogenesis

Topics: Animals; Benzopyrenes; Cocarcinogenesis; Female; Humans; Male; Mammary Neoplasms, Experimental; Mice; Mining; Neoplasms; Neoplasms, Experimental; Neoplasms, Radiation-Induced; Osteosarcoma; Plutonium; Polonium; Pregnancy; Quartz; Radon; Rats; Respiratory Tract Neoplasms; Smoking; Uranium

Chronic inhalation intake of benzo(a)pyrene (BP) and polonium-210 (210Po) together with aluminum oxide caused increase of tumor formation in the lungs of mice. Synergy of BP and 210Po carcinogenic effect was pointed out, it was characterized by summation and possible effect involution by tumor development rates and the duration of the latent period. BP and 210Po carcinogenic effectiveness depended on the type of dust carrier and probably on the presence of silicon dioxide and also carcinogenic metals. It was pointed out that further studies were necessary to determine an etiologic role of mineral dust chemical components in carcinogenic activity of the above substances and also carcinogenic effectiveness of dusts as carriers of chemical carcinogens and alpha-active radionuclides.

Topics: Administration, Inhalation; Aluminum; Aluminum Oxide; Animals; Benzo(a)pyrene; Cocarcinogenesis; Drug Synergism; Dust; Female; Lung; Lung Neoplasms; Mice; Neoplasms, Radiation-Induced; Polonium

Lung cancer induction is commonly regarded as the most important somatic risk arising from the inhalation of radon and its decay products. Relating carcinogenesis to radiation exposure needs a detailed knowledge of the cellular dose distribution in the human respiratory tract. Different dosimetric models have been developed for the determination of cellular doses, particularly for the basal cells of the bronchial epithelium which are considered as the critical cells for lung cancer induction. Part 1 of the paper describes the influence of various environmental as well as anatomical and physiological factors on the resulting dose. Significant inter- as well as intra-subject variabilities of structural components of the human lung, respiration characteristics and clearance mechanisms demonstrate the necessity of applying stochastic models in lung dosimetry.

Topics: Adolescent; Adult; Bismuth; Child; Child, Preschool; Cilia; Cocarcinogenesis; Humans; Humidity; Lead; Lung Neoplasms; Neoplasms, Radiation-Induced; Polonium; Radiation Dosage; Radon Daughters; Respiration; Risk

Benzo(a)pyrene and 210Po were administered both simultaneously and sequentially by intratracheal instillations to Syrian golden hamsters in experiments designed to identify any synergistic interactions between these carcinogens. Their effects were additive after simultaneous administration. A significant synergistic interaction between the two agents appeared to occur when benzo(a)pyrene exposure followed 4 months after 210Po exposure. Most of this effect could be ascribed, however, to a potentiating effect of subsequent 0.9% NaCl solution instillations on 210Po carcinogenesis. These results emphasize the fact that seemingly innocuous stimuli may significantly potentiate lung carcinogenesis. The implications of these findings in terms of the interactions between alpha-radiation and cigarette smoke in human populations are discussed.

Topics: Adenocarcinoma; Alpha Particles; Animals; Benzopyrenes; Carcinoma, Squamous Cell; Cocarcinogenesis; Cricetinae; Humans; Lung Neoplasms; Male; Mesocricetus; Neoplasms, Experimental; Neoplasms, Radiation-Induced; Polonium; Smoking; Sodium Chloride; Solutions