1. Gastroenterological Center Yokohama City University Medical Center Yokohama Japan
2. Department of Gastroenterology Saiseikai Yokohamashi Nanbu Hospital Yokohama Japan
3. Department of Gastroenterology Yokohama Minami Kyosai Hospital Yokohama Japan
4. Department of Gastroenterology Fujisawa City Hospital Fujisawa Japan
5. Department of Gastroenterology, Graduate School of Medicine Yokohama City University Yokohama Japan
6. Department of Gastroenterology Yokosuka City Hospital Yokosuka Japan
7. Department of Gastroenterology Kanagawa Prefectural Ashigarakami Hospital Ashigarakami Japan