1. Division of Endoscopy, Shimane Prefectural Central Hospital, Shimane, Japan
2. Division of Gastroenterology, Shimane Prefectural Central Hospital, Shimane, Japan
3. Division of Liver, Shimane Prefectural Central Hospital, Shimane, Japan
4. Division of Pathology, Shimane Prefectural Central Hospital, Shimane, Japan
5. Division of Endoscopy, Kaken Hospital, International University of Health and Welfare, Chiba, Japan