1. Gastrointestinal Endoscopy Service. Gastroenterology Department, Clinics Hospital, University of Sao Paulo School of Medicine, Sao Paulo, Brazil
2. Surgical Division, Gastroenterology Department, Clinics Hospital, University of Sao Paulo School of Medicine, Sao Paulo, Brazil
3. Basil I. Hirschowitz Endoscopic Center of Excellence, Division of Gastroenterology and Hepatology, UAB School of Medicine, Birmingham, Alabama, USA