1. Division of Gastroenterology; Department of Translational Research and New Technology in Medicine and Surgery; University of Pisa; Pisa Italy
2. Division of Gastroenterology; Department of Surgery, Oncology and Gastroenterology; University of Padua; Padua Italy
3. Gastroenterology and Hepatology Unit; Internal Medicine Department; Assiut University Hospital; Assiut Egypt
4. Division of Gastroenterology; Department of Internal Medicine (DIMI); University of Genoa; Genoa Italy