1 Department of Internal Medicine, Institute of Gastroenterology, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo, 162-8666, Japan. ynakai-tky@umin.ac.jp.
2 Department of Internal Medicine, Institute of Gastroenterology, Tokyo Women's Medical University, 8-1 Kawada-Cho, Shinjuku-Ku, Tokyo, 162-8666, Japan.