1. Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2. Department of Pathology, Central Draft Physical Examination Office, Military Manpower Administration, Daegu, Korea.
3. Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
4. Division of Gastroenterology, Department of Internal Medicine, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, Korea.