title: Pulmonary response to Mount St. Helens' volcanic ash.
abstract: The pulmonary response to a sedimented sample of Mount St. Helens' volcanic ash from the first eruption was studied at 1, 7, 28, 90, and 180 days postintratracheal administration of 1 or 10 mg of ash in specific-pathogen-free rats. One day administration of volcanic ash all animals exhibited a marked inflammatory cell response centered on respiratory bronchioles in which polymorphonuclear leukocytes predominated. At 7 days the reaction was characterized by mononuclear cellular infiltrates. The macrophages within the respiratory bronchioles and alveoli contained intracytoplasmic ash particles. At 28 days the intraalveolar aggregates of mononuclear cells had condensed to form granulomas. Most of the granulomas contained foreign body-type giant cells and some showed central necrosis. The granulomas enlarged in size from 28 days until the termination of the experiment at 180 days with progressive increase in the amount of collagenous tissue. The results of these studies suggest that the volcanic ash may pose a risk for pneumoconiosis in heavily exposed human populations.
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects*; D000818:Animals; D002244:Carbon / Q000009:adverse effects*; D005260:Female; D008168:Lung / Q000648:ultrastructure; D008297:Male; D011009:Pneumoconiosis / Q000209:etiology* / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains; D013047:Specific Pathogen-Free Organisms; D014861:Washington
chemical_list: D000393:Air Pollutants; D002244:Carbon