1. Department of Gastroenterology and Nephrology, Graduate School of Medicine; Chiba University; 1-8-1 Inohana Chuo-ku, Chiba 260-8670 Japan
2. Department of Gastroenterology; Seikeikai Chiba Medical Center; Chiba Japan
3. Division of Pathology; Shonan Fujisawa Tokushukai Hospital; Fujisawa Japan