1. Gastroenterology, Hepatology & Digestive Endoscopy Section, Department of Medicine and Surgery, University of Perugia
2. Gastroenterology & Hepatology Unit, Santa Maria della Misericordia Hospital
3. Public Health Section, Department of Medicine and Surgery, University of Perugia
4. Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, Perugia, Italy