1. Department of Medicine; Michael E. DeBakey VAMC and Baylor College of Medicine; Houston Texas
2. GI Division, Ren Ji Hospital, School of Medicine; Shanghai Jiao Tong University, Shanghai Institution of Digestive Disease; Shanghai China
3. Key Laboratory of Gastroenterology & Hepatology; Ministry of Health; Shanghai China
4. Dipartimento di Scienze Mediche, Chirurgiche e Sperimentali, Clinica Medica; University of Sassari; Sassari Italy