1. From the Medical and Research Services (J.C.Q.V., M.N.B., J.M.A., J.R.R., M.G.J.), Ralph H. Johnson Veterans Affairs Medical Center; and the Division of Nephrology (J.C.Q.V., K.J.R., C.E.H., A.M.B., M.N.B., J.M.A., W.R.F., J.R.R., M.G.J.), Department of Medicine, Medical University of South Carolina, Charleston.