1. From the Departments of Nephrology (J.T.K., S.G., J.M., D.F.), Neuroradiology (F.D.), and Psychiatry (A.K.), Medical School, Hannover, and the Institute for Clinical Pharmacology (J.M.-L., F.S., S.M.B.-B.), Otto von Guericke Universität, Magdeburg, Germany, and the Division of Cardiovascular Medicine (J.T.K., J.P.C.), Stanford University School of Medicine, Stanford, Calif.