[1] Univ Washington, Div Pulm & Crit Care Med, Dept Med, Seattle, WA 98195 USA
[2] Univ Washington, Dept Physiol & Biophys, Seattle, WA 98195 USA
[3] Univ Washington, Dept Pathol, Seattle, WA 98195 USA
[4] Vet Affairs Puget Sound Healthcare Syst Med Res S, Seattle, WA 98195 USA