1 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX.
2 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX ; Department of Internal Medicine, VA North Texas Health Care System, Dallas VA Medical Center, Dallas, TX.
3 Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX ; Department of Surgery, VA North Texas Health Care System, Dallas VA Medical Center, Dallas, TX.