1. Department of Gastroenterology, the First Affiliated Hospital of Dalian Medical University, China
2. Department of Pathology, Dalian Municipal Central Hospital, Dalian, Liaoning Province, China
3. Department of Gastroenterology, Harrison International Peace Hospital, Hengshui, Hebei Province, China
4. Department of Anesthesiology, the First Affiliated Hospital of Dalian Medical University, China