[1] NHLBI, Lung Biol & Dis Program, Div Lung Dis, Rockledge Ctr 2, Bethesda, MD 20892 USA
[2] NHLBI, Div Heart & Vasc Dis, Bethesda, MD 20892 USA
[3] Harvard Univ, Cardiovasc Res Ctr, Boston, MA 02115 USA
[4] Harvard Univ, Div Vasc Res, Boston, MA 02115 USA
[5] Univ Penn, Dept Rehabil Med, Philadelphia, PA 19104 USA
[6] Univ Alabama, Dept Anesthesiol, Birmingham, AL USA
[7] Univ Toronto, Div Cardiovasc Res, Toronto, ON, Canada