[1] Med Univ Vienna, Div Gastroenterol & Hepatol, Vienna, Austria
[2] Haukeland Hosp, Inst Med, N-5021 Bergen, Norway
[3] Karolinska Univ Hosp, Dept Gastroenterol & Hepatol, Stockholm, Sweden
[4] Univ Basel Hosp, Div Gastroenterol & Hepatol, CH-4031 Basel, Switzerland
[5] Markus Krankenhaus, Dept Med 1, Frankfurt, Germany
[6] Haugesund Hosp, Surg Clin, Haugesund, Norway
[7] Hosp Clin Univ, Serv Aparato Digest, Zaragoza, Spain
[8] Linkoping Univ Hosp, Div Gastroenterol & Hepatol, Linkoping, Sweden
[9] Univ Hosp Heraklion, Dept Gastroenterol, Iraklion, Greece
[10] Univ Med Ctr Utrecht, Dept Gastroenterol, Utrecht, Netherlands
[11] Barts & London NHS Trust, Dept Gastroenterol, London, England
[12] Goethe Univ Frankfurt, Med Ctr, Div Gastroenterol & Hepatol, Frankfurt, Germany
[13] John Radcliffe Hosp, Gastroenterol Unit, Oxford OX3 9DU, England
[14] Univ Hosp Gasthuisberg, Dept Gastroenterol, B-3000 Louvain, Belgium