1. From the Wake Forest University School of Medicine (R.P.B., C.D.F., D.M.H., W.R., T.C., W.B.A.), Winston-Salem, NC; Baylor College of Medicine (J.A.H.), Houston, Tex; University of Minnesota (D.H.), Minneapolis; University of Miami School of Medicine (M.L.), Miami, Fla; and University of California (L.C., C.C.I.), San Francisco.