1. Department of Visceral, Vascular and Endocrine Surgery, Martin Luther University Halle-Wittenberg, Ernst-Grube-Str. 40, D-06097 Halle (Saale), Germany
2. Department of Endocrinology, Diabetology and Metabolism, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany
3. Department of General, Visceral and Transplantation Surgery, Division of Endocrine Surgery, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany