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
4. Department of Emergency and Critical Care Medicine; Graduate School of Medicine, Chiba University; Chiba Japan