title: Lung changes in rats following inhalation exposure to volcanic ash for two years.
abstract: Rats were exposed by inhalation to 5 or 50 mg/m3 Mount St. Helens volcanic ash, to 50 mg/m3 quartz (positive controls), or to filtered room air (sham-exposed controls), for 6 hr/day, 5 days/week, for up to 24 months to investigate biological effects of chronic inhalation exposure to volcanic ash under controlled laboratory conditions. Exposure-related lung changes comprised accelerated respiratory frequency; alveolar macrophage accumulation; interstitial reaction; lymphoreticular reaction in peribronchiolar regions and in mediastinal lymph nodes; alveolar proteinosis in the 50- mg/m3 ash- or quartz-exposed groups; increase in fresh lung weights; decreased body weight and increased mortality in the quartz-exposed group; and epidermoid carcinomas especially in the quartz-exposed females and, to a lesser extent, in the 50-mg/m3 ash-exposed females. The observed changes reflect significant dose-response and agent-response relationships.
mesh_terms: D000336:Aerosols; D000393:Air Pollutants; D000818:Animals; D001273:Atmosphere Exposure Chambers; D001835:Body Weight / Q000187:drug effects; D002244:Carbon / Q000378:metabolism / Q000633:toxicity*; D005260:Female; D008168:Lung / Q000032:analysis / Q000187:drug effects* / Q000473:pathology; D008297:Male; D011791:Quartz / Q000378:metabolism / Q000633:toxicity; D051381:Rats; D011916:Rats, Inbred F344; D012119:Respiration / Q000187:drug effects; D012825:Silicon / Q000032:analysis
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D011791:Quartz; D002244:Carbon; D012825:Silicon