1. From the University of Missouri-Columbia (G.C.F.), Columbia, Mo; McMaster University (J.P., S.Y., S.J.C.), Hamilton, Ontario, Canada; Brigham and Women’s Hospital (M.A.P., S.Z.G.), Harvard Medical School, Boston, Mass; Duke University (C.B.G.), Durham, NC; VA Medical Center and University of Minnesota (I.S.A), Minneapolis, Minn; University of Texas (R.H.), San Antonio, Tex.