1. Cardiorenal Research Laboratory, Department of Cardiovascular Medicine, Mayo Clinic, Rochester MN (H.H.C., S.R.I., J.S., J.C.B.).
2. Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas (S.-H.W.).
3. Department of Internal Medicine, University of Parma, Parma, Italy (V.C.).
4. Integrium, Tustin, CA (J.N.).