1. Division of Gastroenterology and Hepatology Department of Internal Medicine Keio University School of Medicine Tokyo Japan
2. Department of Gastroenterology and Hepatology Tokyo Dental College Ichikawa General Hospital Ichikawa City Japan
3. Department of Surgery Keio University School of Medicine Tokyo Japan
4. Department of Gastroenterology and Hepatology National Hospital Organization Saitama Hospital Wako City Japan
5. Department of Gastroenterology International University of Health and Welfare School of Medicine Narita City Japan
6. Division of Pharmacotherapeutics Keio University School of Pharmacy Tokyo Japan