1. From the Department of Internal Medicine (J.D.M., R.M.W., K.M.S., L.E.C., R.M.B., and D.D.H.), University of Iowa Carver College of Medicine, Iowa City; the Department of Veterans Affairs Medical Center (K.Z. and D.D.H.), Iowa City, IA; and the Department of Pharmacology (D.D.H.), University of Iowa Carver College of Medicine, Iowa City.