1. Department of Digestive Diseases, Sant’Orsola-Malpighi Hospital, Bologna, Italy;
2. L. Sacco, Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy;
3. Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy;
4. Department of Health Sciences, San Paolo Hospital, University of Milan, Milan, Italy