Institution: | ? Division of Gastroenterology and Hepatology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan § Department of Physiology, Keio University School of Medicine, Tokyo, Japan ‡ Department of Medicine and Therapeutics, Control and Prevention of Infectious Diseases, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan ∥ Department of Surgery, Yokohama Municipal Citizen's Hospital, Yokohama, Japan |