1. From the Department of Molecular Physiology and Biophysics (N.M., S.S., R.J.v.O., S.S., N.L., D.G.S., J.H.B., X.H.T.W.) and the Department of Medicine, Division of Cardiology (N.M., X.H.T.W.), Baylor College of Medicine, Houston, Tex; and Methodist Hospital/Weill College of Medicine at Cornell University (S.W., M.V.), Houston, Tex.