1. Department of Gastroenterology and Hepatology University Hospital of Zurich University of Zurich 8091 Switzerland
2. Maurice Müller Laboratories Department for Biomedical Research University Clinic of Visceral Surgery and Medicine, Inselspital, University of Bern Bern 3010 Switzerland
3. Department of Pharmacology and Department of Anesthesiology and Pain Medicine and Cardiovascular Research Centre University of Alberta Edmonton T6G 2G3 Canada
4. Division of Clinical Chemistry and Biochemistry University Children's Hospital Zurich Zurich 8032 Switzerland
5. Division of Gastroenterology and Hepatology University of North Carolina Chapel Hill NC 27599‐7080 USA