title: Particle activity and in vivo pulmonary response to freshly milled and aged alpha-quartz.
abstract: This study examined the possibility of freshly fractured alpha-quartz being more toxic and inflammatory in vivo than aged quartz of the same composition and particle size. Fresh quartz was generated by a jet mill, and used immediately, while aged dust was stored for two months before use. Both the production of hydrogen peroxide and hydroxyl radicals and the analysis of surface radicals verified the enhanced surface activity of fresh quartz. Male Fischer 344 rats were exposed to fresh or aged alpha-quartz by inhalation (20 mg center dot m-3, 5 h per day, 5 d per week, for 2 weeks) and their pulmonary responses were determined 1--3 d postexposure. Exposure to aged quartz resulted in an increase in cytotoxic and inflammatory parameters. In comparison, the inhalation of freshly cleaved quartz resulted in dramatically greater increases in all of the pulmonary responses. This finding suggests that exposure to freshly machined quartz may result in a greater risk of pulmonary disease.
authors.affiliation: Division of Biomedical and Behavioral Science, National Institute for Occupational Safety and Health, Cincinnati, OH 45226, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Shoemaker
authors.forename: J R
authors.initials: JR
authors.lastname: Pretty
authors.forename: D M
authors.initials: DM
authors.lastname: Ramsey
authors.forename: J L
authors.initials: JL
authors.lastname: McLaurin
authors.forename: A
authors.initials: A
authors.lastname: Khan
authors.forename: A W
authors.initials: AW
authors.lastname: Teass
authors.forename: V
authors.initials: V
authors.lastname: Castranova
authors.forename: W H
authors.initials: WH
authors.lastname: Pailes
authors.forename: N S
authors.initials: NS
authors.lastname: Dalal
authors.forename: P R
authors.initials: PR
authors.lastname: Miles
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology*; D016001:Confidence Intervals; D004195:Disease Models, Animal; D017563:Lung Diseases, Interstitial / Q000139:chemically induced* / Q000503:physiopathology; D008297:Male; D010865:Pilot Projects; D011791:Quartz / Q000008:administration & dosage / Q000009:adverse effects*; D051381:Rats; D011916:Rats, Inbred F344; D012829:Silicosis / Q000209:etiology / Q000503:physiopathology
chemical_list: D011791:Quartz