1. From the Brigham and Women's Hospital, Harvard Medical School, Boston, MA (N.R.C., N.P.P., J.E.M., P.MR.); Brown University School of Medicine, Providence, RI (C.B.E.); George Washington University School of Medicine, Washington, DC (L.W.M.); University of Iowa, Iowa City (J.G.R.); National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (J.E.R.); and Albert Einstein College of Medicine, Bronx, NY (S.W.-S.).