[1] Massachusetts Gen Hosp, Liver Ctr, Boston, MA 02114 USA
[2] Massachusetts Gen Hosp, Gastrointestinal Div, Boston, MA 02114 USA
[3] Harvard Med Sch, Boston, MA 02114 USA
[4] Sichuan Univ, Western China Hosp, Chengdu, Peoples R China
[5] Massachusetts Gen Hosp, Liver Ctr, Div Gastroenterol, Dept Med, Boston, MA 02114 USA
[6] Chinese Acad Med Sci & Peking Union Med Coll, Beijing, Peoples R China