1. Division of Gastroenterology and Hepatology, Department of Internal Medicine, Institute for Medical Sciences, Chonbuk National University Medical School and Hospital, Jeonju 561-712, Korea.
2. Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea.
3. Department of General Surgery, Chonbuk National University Medical School and Hospital, Jeonju 561-712, Korea.