1. Department of Surgery, Suwa Central Hospital, 4300 Tamagawa, Chino, Nagano 3918503, Japan
2. Department of Medical Education Studies, International Research Center for Medical Education, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033, Japan
3. Department of Internal Medicine, Suwa Central Hospital, 4300 Tamagawa, Chino, Nagano 3918503, Japan