1. Section of Digestive Diseases; VA-Connecticut Healthcare System; West Haven CT USA
2. Section of Digestive Diseases; Yale School of Medicine; New Haven CT USA
3. Division of Gastroenterology; Azienda Ospedaliero-Universitaria di Modena and University of Modena and Reggio Emilia; Modena Italy
4. Department of Medicine; Federal University of Sao Carlos; Sao Carlos Brazil