1. Institute for Transfusion Medicine, University Hospital, University Duisburg-Essen, Essen, Germany
2. Division of Paediatric Surgery, Department of General-Visceral and Transplant Surgery, University Hospital, University Duisburg-Essen, Essen, Germany
3. Department of General-Visceral and Transplant Surgery, University Hospital, University Duisburg-Essen, Essen, Germany
4. Department of Pediatric Gastroenterology, Clinic for Pediatrics II, University Hospital, University Duisburg-Essen, Essen, Germany
5. Department of Pediatric, University Hospital, University Duisburg-Essen, Essen, Germany
6. Department of Pediatrics, University Hospital Duisburg, Germany