1. Division of Surgery; Department of Surgery; Second University of Naples; Naples Italy
2. Division of Gastroenterology; Department of Internal Medicine; University of Pisa; Pisa Italy
3. Division of Gastroenterology; Department of Internal Medicine; University of Genoa; Genoa Italy
4. Division of Gastroenterology; Department of Surgery, Oncology and Gastroenterology; University of Padua; Padua Italy
5. Digestive Physiology; Hospices Civils de Lyon; Lyon I University and Labtau, INSERM 1032; Lyon France