Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine,Seoul National University College of Medicine; Clinical Research Institute, Seoul National University Hospital; Lung Institute, Medical Research Center, Seoul National University, Korea.
Address for correspondence: Chul-Gyu Yoo, M.D., Ph.D. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea. Phone: 02-760-3760, Fax: 02-762-9662, cgyoo@snu.ac.kr