1. Division of Gastroenterology, Department of Internal Medicine, Incheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul 403-720, Republic of Korea
2. Bucheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul 403-720, Republic of Korea
3. Yeouido St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul 403-720, Republic of Korea
4. Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul 403-720, Republic of Korea
5. St. Paul’s Hospital, College of Medicine, The Catholic University of Korea, Seoul 403-720, Republic of Korea