title: Breath isoprene: temporal changes in respiratory output after exposure to ozone.
abstract: Isoprene is a major hydrocarbon found in human breath. This study was conducted to evaluate whether respiratory isoprene output could serve as a monitor for ozone exposure. Healthy young adult subjects (n = 10) underwent chamber exposure on separate days to filtered air and to a variable concentration of ozone. Exposures had durations of 130 min that included alternate periods of rest and light treadmill exercise; breath was sampled pre- and postexposure. For six subjects, breath was resampled 19 +/- 1 h postexposure. Breath samples were concentrated cryogenically and analyzed by capillary gas chromatography. Isoprene output immediately postexposure was significantly reduced by ozone or filtered air (17 and 19%, respectively). These results suggest that exercise alone reduces isoprene levels in breath without an additive ozone effect. However, in the six subjects restudied 19 +/- 1 h postexposure to ozone, breath isoprene concentrations were now increased above the preexposure output by 99% (P < 0.01) and exceeded the 51% increase in output of isoprene at this time point after filtered-air exposure (P < 0.01). Therefore, breath isoprene is proposed as a noninvasive marker of a physiological response to oxidant-induced injury to epithelial membranes and fluid linings of the lower respiratory tract by ozone.
authors.forename: W M
authors.initials: WM
authors.lastname: Foster
authors.forename: L
authors.initials: L
authors.lastname: Jiang
authors.forename: P T
authors.initials: PT
authors.lastname: Stetkiewicz
authors.forename: T H
authors.initials: TH
authors.lastname: Risby
mesh_terms: D000328:Adult; D015415:Biomarkers; D001944:Breath Tests; D002070:Butadienes / Q000032:analysis / Q000378:metabolism*; D002849:Chromatography, Gas; D005260:Female; D005540:Forced Expiratory Flow Rates; D045782:Hemiterpenes; D006801:Humans; D008176:Lung Volume Measurements; D008297:Male; D010083:Oxidants, Photochemical / Q000378:metabolism*; D010126:Ozone / Q000378:metabolism*; D010420:Pentanes; D013997:Time Factors; D014797:Vital Capacity
chemical_list: D015415:Biomarkers; D002070:Butadienes; D045782:Hemiterpenes; D010083:Oxidants, Photochemical; D010420:Pentanes; C005059:isoprene; D010126:Ozone