1. Digestive Endoscopy Unit, St. Barbara Hospital, Iglesias, Italy
2. Digestive Diseases Center, Vitkovice Hospital, Ostrava, Czech Republic
3. Division of Digestive Endoscopy and Gastroenterology, Valduce Hospital, Como, Italy
4. Department of Surgical Sciences, University of Cagliari, Cagliari, Italy
5. Department of Medical Research, Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chiayi, Taiwan
6. Sepulveda Ambulatory Care Center, Veterans Affairs Greater Los Angeles Healthcare System, North Hills, California, United States