1. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
2. Department of Gastroenterology and Hepatology, Hiroshima City Hiroshima Citizens Hospital, Hiroshima, Japan
3. Department of Gastroenterology, Okayama City Hospital, 3-20-1 Kitanagase-omotemachi, Kita-ku, Okayama, Japan