1. Division of Gastroenterology, Department of Medicine,Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, CA
2. Department of Radiology,Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, CA
3. Department of Pathology,Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, CA
4. Division of Epidemiology, Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, CA