1. Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan
2. Gastroenterology Medicine Center, Shonan Kamakura General Hospital, Japan
3. Department of Gastroenterology, Nayoro City General Hospital, Japan
4. Department of Gastroenterology, Hokkaido P.W.F.A.C. Asahikawa Kousei General Hospital, Japan
5. Department of Gastroenterology, Shibetsu City Hospital, Japan