1. Division of Gastroenterology, Hepatology, and Nutrition, Virginia Commonwealth University, Richmond, Virginia, USA
2. Department of Gastroenterology and Hepatology, Elson Floyd College of Medicine, Spokane, Washington, USA
3. Department of Medicine, Rush University, Chicago, Illinois, USA
4. Rutgers New Jersey Medical School, Newark, New Jersey, USA
5. Salix Pharmaceuticals, Bridgewater, New Jersey, USA
6. Central Virginia Veterans Healthcare System, Richmond, Virginia, USA