[1] St Georges Univ London, London SW17, England
[2] Mayo Clin, Div Gastroenterol & Hepatol, Rochester, CA USA
[3] Univ Queensland, Sch Biomed Sci, Brisbane 4072, Australia
[4] Clarunis Univ Ctr Gastrointestinal & Liver Dis, St Clara Hosp & Univ Hosp, CH-4002 Basel, Switzerland
[5] Univ Basel, Fac Med, Dept Biomed Engn, CH-4123 Allschwil, Switzerland