1. From the Department of Internal Medicine (H.A.G.), Medical Clinic II/V, University Hospital Giessen and Marburg GmbH, Giessen, Germany; Experimental Medicine & Toxicology (M.W.W.), Imperial College London, Hammersmith Hospital, London, United Kingdom; and Center for Pulmonary Hypertension (S.R.), Section of Cardiology, University of Chicago, Chicago, Ill.