1. Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan
2. Division of Gastroenterology and Hepatology, Department of Medicine, Chiyoda-ku, Nihon University School of Medicine, Chiyoda-ku, Tokyo, Japan
3. Department of Gastroenterology and Metabolism, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan