Affiliation: | 1. Internal Medicine, Yokote Municipal Hospital, 5‐31 Negishi‐cho, Yokote‐shi, Akita 013‐8602, Japan;2. Gastroenterology, Akita Red Cross Hospital, 222‐1 Kamikitade Saruta, Akita‐shi, Akita 010‐1495, Japan;3. Hitachi Medical Corporation, 1‐11‐1 Hon‐cho, Aoba‐ku, Sendai‐shi, Miyagi 980‐0014, Japan |