[1] Chinese Univ Hong Kong, Dept Surg, Sha Tin, Hong Kong, Peoples R China
[2] Chinese Univ Hong Kong, Inst Digest Dis, Sha Tin, Hong Kong, Peoples R China
[3] Oxford PharmaGenesis TM Ltd, Res Evaluat Unit, Oxford, England
[4] Northwestern Univ, Feinberg Sch Med, Div Gastroenterol, Chicago, IL 60611 USA
[5] Hosp Univ Penn, Dept Gastroenterol, Philadelphia, PA 19104 USA