1. Gastroenterology Unit, Ospedali Riuniti di Foggia, Foggia, Italy
2. Moores Cancer Center, University of California at San Diego, La Jolla
3. Division of Gastroenterology and Hepatology, University of Utah School of Medicine, Salt Lake City
4. Section of Gastroenterology, Veterans Affairs San Diego Healthcare System, San Diego, California
5. Division of Gastroenterology, University of California at San Diego, La Jolla