1. Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
2. Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
3. Department of Gastroenterology, Yuri-Kumiai General Hospital, Akita, Japan
4. Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, 1–6, Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8309, Japan