1. Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, 1670 University Boulevard, Volker Hall B140, Birmingham, AL 35294-0019, USA
2. Cardiovascular Division, Department of Medicine, University of Minnesota, 420 Delaware Street SE, MMC 508, Minneapolis, MN 55455, USA
3. School of Nursing, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294-1210, USA
4. Vascular Biology and Hypertension Program, Department of Medicine, University of Alabama, 1900 University Boulevard, Birmingham, AL 35233, USA
5. Section of Cardiology, Birmingham Veterans Affairs Medical Center, 700 19th Street South, Birmingham, AL 35233, USA