1. Division of Gastroenterology, “Brotzu” Hospital, 09124 Cagliari, Italy
2. Territorial Gastroenterology Service, ASL BAT, 76123 Andria, Italy
3. Department of Medical and Surgical Sciences, School of Medicine, Catholic University, 00168 Rome, Italy
4. Department of Medicine, Surgery and Pharmacy, University of Sassari, 07100 Sassari, Italy
5. Baylor College of Medicine, One Baylor Plaza Blvd., Houston, TX 77030, USA