1. From Departments of Biochemistry (C.I.S., Q.K., L.E., B.K., G.A.W.), Pharmacology (J.T.T.), Physiology (M.W., M.S.), and Internal Medicine (M.W., M.S.), University of Missouri-Columbia, Columbia, Mo; Biomedical Sciences Department (R.C.G.), Southwest Missouri State University, Springfield, Mo; and Department of Chemistry (F.A.G.), University of Puerto Rico, Río Piedras, Puerto Rico.