1. Internal Medicine Department, Division of Gastroenterology, Kasr Al-Aini School of Medicine, Cairo University, Cairo, Egypt
2. Hospital of the Ministry of Interior and Administration, Endoscopy Unit, Department of Gastroenterology, Szczecin, Poland
3. Armed Forces College of Medicine, Cairo, Egypt
4. Internal Medicine Department, Hepatology and Gastroenterology Unit, Mansoura Faculty of Medicine, Mansoura University, Mansoura, Egypt
5. Baylor St. Luke’s Medical Center Houston, Texas, United States
6. Department of Gastroenterology and Hepatology, Military Medical Academy, Cairo Egypt
7. Internal Medicine, gastroenterology and Hepatology Department, Assiut University, Assiut, Egypt