[1] Humboldt Univ, Dept Pediat, Berlin, Germany
[2] Humboldt Univ, Dept Med, Berlin, Germany
[3] Humboldt Univ, Inst Lab Med & Pathobiochem, Berlin, Germany
[4] Univ Zurich Hosp, Dept Med, Div Gastroenterol, CH-8091 Zurich, Switzerland
[5] Derriford Hosp, Dept Surg, Plymouth PL6 8DH, Devon, England
[6] Univ Magdeburg, Dept Surg, D-39106 Magdeburg, Germany
[7] OutPatient Clin Addict Dis, Magdeburg, Germany
[8] Univ Hamburg, Klinikum Eppendorf, Dept Surg, Hamburg, Germany
[9] Univ Leipzig, Dept Med, D-7010 Leipzig, Germany