Blood borne markers in humans during multi-day exposure to
ozone.
Foster, W. Michael, Marsha Wills-Karp, Clarke G. Tankersley, Xiaoling
Chen, and Nicole C. Paquette.
DEPARTMENT OF ENVIRONMENTAL HEALTH SCIENCES, SCHOOL OF HYGIENE AND
PUBLIC HEALTH, THE JOHNS HOPKINS UNIVERSITY, BALTIMORE, MD 21205
APStracts 3:0133A, 1996.
Intermittent exposure of the human lung to ambient levels of O3 was
assayed in systemic fluids using serum [alpha]-tocopherol (ST) as a
gauge of oxidative stress, and the blastogenic activity of peripheral
blood monocytes (PBM) as an index of immune function. Healthy men
(n=10) were evaluated over 3 consecutive days (130 min/d) of chamber
exposure to O3 and filtered air (FA); subjects alternated between
rest and light treadmill exercise during exposures. For O3, level was
varied at 20 min intervals, i.e., 250, 350, 450, 450, 350, 250 ppb
and concluded with 10 min at 250 ppb. ST was quantitated by HPLC
techniques; and T-lymphocyte blastogenesis was measured in cell
cultures of PBM by comparing [3H]thymidine incorporation in mitogen
stimulated (concanavalin A) and non-stimulated cells. Following the
3rd day of O3 at 20 hr post-exposure, ST levels were reduced
significantly as compared to FA controls (down 14%, -0.96 [mu]mol/l).
Mitogen activated T-lymphocytes exhibited a 61% increase in
blastogenic activity after 3 days of O3 exposure, significant as
compared to the proliferative activity of activated T-lymphocytes
collected after FA or prior to O3. Acutely airway function was
impaired by O3, e.g., on day 1 the FVC and FEV1 were decreased 8% (
-0.92 l) and 14% (-0.86 l/s) from pre-exposure values and full
recovery was delayed beyond 24 hours. Effects of O3 exposure on
cellular and biochemical markers increased in magnitude after each
exposure and did not parallel the apparent adaptability of bronchial
sensitivity to O3.
Received 4 October 1995; accepted in final form 23 February 1996.
APS Manuscript Number A1073-5.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 20 March 96