1. From the Department of Pathophysiology (J.T., A.R., A.K.), Semmelweis University, Budapest, Hungary; the Department of Physiology (J.T., P.M.K., M.S.W., A.K.), New York Medical College, Valhalla; and the Division of Clinical Physiology (Z.B.), Institute of Cardiology, University of Debrecen, Debrecen, Hungary.