1. Department of Gastroenterology, General Hospital of Northern Theater Command (formerly General Hospital of Shenyang Military Area), Shenyang, P.R. China
2. Postgraduate College, Jinzhou Medical University, Jinzhou, P.R. China
3. Department of No.1 Cadre Ward, General Hospital of Northern Theater Command (formerly General Hospital of Shenyang Military Area), Shenyang, P.R. China
4. Department of Gastroenterology and Hepatology, Theodor Bilharz Research Institute, Cairo, Egypt
5. Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia, USA
6. Department of Gastroenterology, General Hospital of Northern Theater Command (formerly General Hospital of Shenyang Military Area), No. 83 Wenhua Road, Shenyang, Liaoning Province 110840, China