title: Pulmonary macrophage phagocytosis and enzyme production after in vivo exposure to silica dust.
abstract: Guinea pigs were exposed to silica dust (SiO2) aerosols at 6, 13, 28, and 46 mg/m3 for 3 weeks and examined 4, 8, 16, and 23 weeks later. Twenty-four milligrams of TiO2 per cubic meter served as the control dust. Lung weights were increased at 8 weeks and later. Free lung cells showed a tendency to decrease in phagocytosis capacity at 8 weeks after cessation of exposure and later. Alveolar macrophage production of N-acetyl-beta-D-glucosaminidase, cathepsin D, and acid phosphatase was decreased at 8 weeks after exposure and later. The relationship between the depressant effect on macrophages and the absence of an exposure-related polymorphonuclear neutrophil response for the development of fibrosis could be part of the mechanism behind fibrosis.
mesh_terms: D000818:Animals; D004391:Dust / Q000009:adverse effects*; D005260:Female; D006168:Guinea Pigs; D008168:Lung / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D009504:Neutrophils / Q000187:drug effects; D010587:Phagocytosis / Q000187:drug effects*; D012822:Silicon Dioxide / Q000633:toxicity*
chemical_list: D004391:Dust; D012822:Silicon Dioxide