1. Department of Gastroenterology, Gifu Municipal Hospital, Gifu 500-8513, Japan
2. First Department of Internal Medicine, Gifu University, Gifu 501-1194, Japan
3. Department of Gastroenterological Endoscopy, Kanazawa Medical University, Ishikawa 920-0293, Japan
4. Department of Gastroenterology, Gifu Prefectural General Medical Center, Gifu 500-8717, Japan
5. Third Department of Internal Medicine, Graduate School of Medicine University of Toyama, Toyama 930-0194, Japan