1. From the Duke Clinical Research Institute (L.H.C., M.A.G., A.M.S., D.J.W., B.G.H., P.S.D.) and Department of Medicine (L.H.C., D.J.W., P.S.D.), Duke University School of Medicine, Durham, NC; and the Department of Medicine (D.J.W.), Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pa.