1. Department of Gastroenterology & Hepatology, Department for Hepatitis Control, Tokyo Medical & Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
2. Division of Gastroenterology & Hepatology, University of Connecticut Health Center, 263 Farmington Avenure, Farmington, CT 06030-1845, USA.