1. Digestive Center for Diagnosis & Treatment, 29 Ayar Street, Damascus, Syrian Arab Republic
2. Division of Gastroenterology and Hepatology, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
3. Division of Anesthesiology and Perioperative Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, USA
4. Division of Health Care Policy and Research, Mayo Clinic, 200 First Street SW, Rochester, MN, USA