1. From the Division of Pulmonary and Critical Care Medicine (M.-J.L., W.-M.Z., X.-R.Y., J.S.K.S.), Division of Gastroenterology (G.P.H.L., C.-M.T.), Johns Hopkins School of Medicine, Baltimore, Md; the Department of Physiology and Biophysics (K.-P.Y.), College of Medicine, University of South Florida, Tampa; and the Department of Physiology and Pathophysiology (M.-J.L.), Fujian Medical University, Fuzhou, Fujian, People’s Republic of China.