1. Department of Gastroenterology, Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, Nanjing, P.R. China
2. School of Medicine, Nanjing University, No.22 Hankou Road, Nanjing, P.R. China
3. Department of Gastroenterology, Subei People’s Hospital of Jiangsu Province, Yangzhou, P.R. China