1. Department of Gastroenterology and Clinical Oncology, Graduate School of Medicine; Chiba University; 1-8-1 Inohana, Chuo-ku Chiba 260-8670 Japan
2. Department of Emergency and Critical Care Medicine; Ichinomiya Municipal Hospital; Ichinomiya Aichi Japan
3. Department of Gastroenterology; Ogaki Municipal Hospital; Ogaki Japan
4. General Internal Medicine; Nagoya Daini Red Cross Hospital; Nagoya Japan
5. Department of Surgery; Teikyo University School of Medicine; Tokyo Japan