1. Department of Gastroenterology, Endocrinology, Rheumatology and Infectious Diseases, University Hospital Regensburg, D-93053 Regensburg, Germany
2. Department of Gastroenterology, University Hospital Heidelberg, D-69120 Heidelberg, Germany
3. Department of General and Transplant Surgery, University Hospital Heidelberg, D-69120 Heidelberg, Germany