1. Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, The University of British Columbia, Kelowna, Canada (A.M.W., P.N.A.).
2. Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada (A.M.W.).
3. Pulmonary and Critical Care Section, VA Loma Linda Healthcare System, Loma Linda, CA (J.D.A., C.G., P.S.).