title: Generation of superoxide (O2-.) from alveolar macrophages exposed to asbestiform and nonfibrous particles.
abstract: Active oxygen species are implicated causally in tumor promotion by 12-O-tetradecanoylphorbol-13-acetate and in cell damage by asbestos, a putative tumor promoter of the respiratory tract. To determine the properties of asbestos important in generation of the oxygen free radical, superoxide (O2-.), hamster and rat alveolar macrophages were exposed in vitro to nontoxic concentrations of fibrous (crocidolite, erionite, Code 100 fiberglass, sepiolite) and nonfibrous (riebeckite, mordenite, glass) particulates. The amount of O2-. released by cells in response to dusts was determined by measuring the reduction of cytochrome c in the presence and absence of superoxide dismutase. Results showed that all fibrous (defined as a greater than 3:1 length:diameter ratio) dusts caused a significant increase in both release of O2-. from rat macrophages and enhancement of zymosan-triggered O2-. from hamster macrophages. Nonfibrous particles were less active than fibers at comparable concentrations. These results suggest that the geometry of particulates is of critical importance in the generation of O2-. from cells of the respiratory tract.
mesh_terms: D000818:Animals; D001194:Asbestos / Q000633:toxicity*; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D005609:Free Radicals; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008647:Mesocricetus; D010316:Particle Size; D011650:Pulmonary Alveoli / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013481:Superoxides / Q000378:metabolism*; D015054:Zymosan / Q000494:pharmacology
chemical_list: D005609:Free Radicals; D013481:Superoxides; D001194:Asbestos; D015054:Zymosan