1. 1Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, U.S.A.
2. 2Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh, Pittsburgh, PA 15261, U.S.A.
3. 3Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, U.S.A.
4. 4Department of Urology, Roswell Park Cancer Center, Buffalo, NY 14263, U.S.A.
5. 5Department of Human Performance - Exercise Physiology, West Virginia University, Morgantown, WV 26506, U.S.A.