title: Preface.
authors.affiliation: Dept. of Medicine, Division of Gastroenterology, Zeidler Bldg 2-24, 130 University Campus, Edmonton, T6G 2X8, Canada.
authors.forename: Levinus Leo A
authors.initials: LL
authors.lastname: Dieleman
authors.affiliation: Rabin Medical Center (RMC), Beilinson Hospital, 39 Jabotinski St., Petah Tikva, 49100, Israel. Electronic address: udiringel@clalit.org.il.
authors.forename: Yehuda Udi
authors.initials: YU
authors.lastname: Ringel