1. Gastroenterology and Endoscopy Unit, S. Elia Hospital, ASP di Caltanissetta, Caltanissetta, Italy
2. Gastroenterology Unit, National Institute of Gastroenterology-IRCCS "Saverio de Bellis", Castellana Grotte, Bari, Italy
3. Gastroenterology Unit, Buccheri La Ferla Fatebenefratelli Hospital, Palermo, Italy
4. Gastroenterology and Endoscopy Unit, Fondazione Istituto San Raffaele G Giglio di Cefalù, Cefalu, Italy
5. Digestive Diseases Endoscopy Unit, Policlinico G. Martino Hospital, University of Messina, Messina, Italy
6. Gastroenterology and Hepatology, The University of Utah School of Medicine, Salt Lake City, United States
7. Gastroenterology Unit, Department of Medical Sciences, University of Foggia, Foggia, Italy