1. Department of General Internal Medicine; Hiroshima University Hospital; 1-2-3 Kasumi, Minami-ku Hiroshima 734-8551 Japan
2. Department of Gastroenterological Surgery; Dokkyo Medical University; Tochigi Japan
3. Department of Medicine and Clinical Oncology, Graduate School of Medicine; Chiba University Hospital; Chiba Japan
4. Department of Internal Medicine; Tokyo Metropolitan Komagome Hospital; Tokyo Japan
5. Department of Gastroenterology; The University of Tokyo; Tokyo Japan
6. Department of Gastroenterological Surgery; Tokai University Hospital; Tokyo Japan
7. Department of Gastroenterology, Second Teaching Hospital; Fujita Health University; Nagoya Japan