1. Department of Medicine, Division of Gastroenterology & Hepatology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA. Email: wu5@jeflin.tju.edu
2. Department of Medicine, Division of Gastroenterology-Hepatology, University of Connecticut School of Medicine, Farmington, Connecticut 06030, USA.
3. College Building, Room 901, Jefferson Medical College, 1025 Walnut Street, Philadelphia, PA 19107-5083, USA. Tel: +1 215 955 6944; Fax: +1 215 923 7697; Email: zern1@jeflin.tju.edu