1. Department of Gastroenterology, National Hospital Organization Ureshino Medical Center, Ureshino, Japan
2. Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, Saga University, Saga, Japan
3. Department of Gastroenterology, Saga-Ken Medical Centre Koseikan, Saga, Japan
4. Department of Internal Medicine, Karatsu Red Cross Hospital, Karatsu, Japan