title: Modification by ozone of lung tumor development in mice.
abstract: Mice, either strain A/J or Swiss Webster, were exposed for 18 weeks either to filtered air or to 0.4 or 0.8 ppm ozone for 8 hours daily. Subgroups in each test group received a single ip injection of 1,000 mg urethan/kg or 0.9% sodium chloride vehicle 1 day prior to initiation of the exposure regimen. Tumor incidence in Swiss Webster mice was 0-3% in groups not receiving urethan and was 61-74% in groups receiving urethan. In A/J mice, the corresponding values were 9-38% and 100%, respectively. Exposure to ozone caused a decrease in the number of tumors per lung in urethan-treated mice of both strains, in a dose-dependent manner. There seemed to be a specific decrease in tumors derived from alveolar type II cells in the A/J mice given urethan plus ozone. Most interesting, perhaps, was a significant increase in the number of tumors per lung in A/J mice exposed to 0.8 ppm ozone without urethan, confirming a previous report by others. The corresponding ozone effect on lung tumor development was not observed in Swiss Webster mice.
authors.forename: J A
authors.initials: JA
authors.lastname: Last
authors.forename: D L
authors.initials: DL
authors.lastname: Warren
authors.forename: E
authors.initials: E
authors.lastname: Pecquet-Goad
authors.forename: H
authors.initials: H
authors.lastname: Witschi
mesh_terms: D000397:Air Pollution / Q000009:adverse effects; D000818:Animals; D003043:Cocarcinogenesis; D004347:Drug Interactions; D006801:Humans; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000473:pathology; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D009378:Neoplasms, Multiple Primary / Q000139:chemically induced* / Q000473:pathology; D010126:Ozone / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D014520:Urethane / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D014520:Urethane; D010126:Ozone