1. Division of Gastroenterology, Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy
2. Division of Gastroenterology, Department of Internal Medicine, University of Genoa, Genoa, Italy
3. Unit of Gastroenterology, Campus Bio-Medico University, Rome, Italy
4. Pathophysiology Unit, Baggiovara Hospital, Modena, Italy