F Dederichs1, I Iesalnieks2,3. 1. Department of Internal Medicine and Gastroenterology, Marienhospital Gelsenkirchen, Virchowstr. 135, 45886, Gelsenkirchen, Germany. F.Dederichs@arcor.de. 2. Department of Surgery, Marienhospital Gelsenkirchen, Gelsenkirchen, Germany. 3. Department of Surgery, Städtisches Klinikum München Bogenhausen, Munich, Germany.