1. From the Pulmonary Hypertension Program, Department of Medicine (Cardiology Division), University of Alberta, Edmonton, Alberta, Canada (E.D.M.); Division of Experimental Medicine, Imperial College of Medicine, London, UK (M.R.W.); Cardiopulmonary Research Program, Department of Pediatrics, Stanford University, Stanford, Calif (M.R.); and Pulmonary Vascular Research Institute, Canterbury, UK (E.D.M., M.R.W., M.R.).