1 From Duke University School of Medicine, Durham (L.E.B.), and the University of North Carolina at Chapel Hill School of Medicine, Chapel Hill (G.C.) - both in North Carolina; the University of California, Davis, School of Medicine, Sacramento (S.A.-G.); Vanderbilt University School of Medicine, Nashville (C.H.W.); the University of Rochester Medical Center, Rochester, NY (R.R., A.V.); and the Medical College of Wisconsin, Milwaukee (L.E.E.).