1. Department of Internal Medicine, JA Shizuoka Kohseiren Enshu Hospital, 1-1-1 Chuo, Naka-ku, Hamamatsu, Shizuoka 430-0929 , Japan
2. Medical Education Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192 , Japan
3. Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192 , Japan
4. Department of Surgery, Maruyama Hospital, 39-10 Sukenobucho, Naka-ku, Hamamatsu, Shizuoka 430-0903 , Japan