1. Departments of Biology, University of Ferrara and Sant'Anna Hospital, Ferrara - Italy
2. Departments of Human Anatomy, University of Ferrara and Sant'Anna Hospital, Ferrara - Italy
3. Departments of Gastroenterology and University of Ferrara and Sant'Anna Hospital, Ferrara - Italy
4. Departments of Surgery, University of Ferrara and Sant'Anna Hospital, Ferrara - Italy