1 Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, 949-7302, Japan. kandatatsuo@gmail.com.
2 Divison of Gastroenterology and Hepatology, Uonuma Institute of Community Medicine, Niigata University Medical and Dental Hospital, Uonuma Kikan Hospital, Minamiuonuma, Niigata, 949-7302, Japan. kandatatsuo@gmail.com.
3 Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, 949-7302, Japan.