1. Department of Internal Medicine, MedStar Georgetown University Hospital, Washington, DC 20007, USA
2. Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, VA 23501, USA
3. Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23284, USA
4. Department of Gastroenterology, Carolinas Medical Center, Charlotte, NC 28203, USA
5. Division of Gastroenterology, Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, VA 23501, USA