[1] Kaiser Permanente Med Ctr, Dept Gastroenterol, San Diego, CA USA
[2] Univ Hosp, Div Gastroenterol, Nottingham, England
[3] Cent Surg, Rugby, England
[4] GKT Sch Med, Dept Gen Practice & Primary Care, London, England
[5] Univ Calif Los Angeles, Sch Med, Div Digest Dis, Los Angeles, CA USA
[6] AstraZeneca R&D Molndal, Molndal, Sweden