1. Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
2. Department of Internal Medicine, George Washington University, Washington, D.C. 20052, USA
3. Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, VA 23507, USA
4. Department of Gastroenterology, Carolinas Medical Center, Charlotte, NC 28203, USA
5. Department of Gastroenterology, Eastern VA Medical School, Norfolk, VA 23507, USA