1. Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
2. Department of Gastroenterology and Hepatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
3. Department of Gastroenterology, Japanese Red Cross Medical Center, Tokyo, Japan
4. Department of Gastroenterology, Tokyo Metropolitan Police Hospital, Tokyo, Japan
5. Department of Gastroenterology and Metabolism, Sapporo Medical University, Sapporo, Japan
6. Department of Gastroenterology, Japanese Red Cross Kitami Hospital, Hokkaido, Japan
7. Department of Gastroenterology, JR Tokyo General Hospital, Tokyo, Japan
8. Department of Gastroenterology, Saitama Medical University International Medical Center, Saitama, Japan
9. Department of Gastroenterology, Mitsui Memorial Hospital, Tokyo, Japan