The following persons participated in the APC Study: Steering Committee: M.M. Bertagnolli, E.T. Hawk, C.J. Eagle; Statistical Team: A.G. Zauber, K.M. Kim, D. Corle, R. Rosenstein, J. Tang, T. Hess, A. Wilton, M. Hsu; Medical Monitors: W. Anderson, L. Doody; Central Pathology Review: M. Redston, K.R. Geisinger; Project Directors: G.M. Woloj, D. Bagheri, A. Crawford, M. Schietrum, V. Ladouceur; Data and Safety Monitoring Board: S. Rosen (chair), L. Friedman, R. Makuch, R. Phillips, P. Taylor; Principal Investigators, United States: S. Auerbach (California Professional Research, Newport Beach), C.F. Barish (Wake Research Associates, Raleigh, NC), T. Barringer (Carolinas Medical Center, Charlotte, NC), R.W. Bennetts (Northwest Gastroenterology Clinic, Portland, OR), M. Blitstein (Associates in Gastroenterology and Liver Disease, Lake Forest, IL), J. Bruggen (Wake Forest University Baptist Medical Center, Winston Salem, NC), P Carricaburu (Veterans Affairs Hospital, Sheridan, WY), D. Chung (Massachusetts General Hospital, Boston, MA), F. Colizzo (Pentucket Medical Associates, Haverhill, MA), R. Curtis (Newton-Wellesley Hospital, Newton, MA), T. Dewar (Harris Methodist Hospital Fort Worth, Ft. Worth, TX), R. DuBois (Vanderbilt University Medical Center, Nashville, TN), T. Feinstat (Gastroenterology Consultants of Sacramento, Roseville, CA), T.R. Foley (Regional Gastroenterology Associates of Lancaster, Lancaster, PA, D. Gabbaizadeh (Huntington Research Group, Huntington Station, NY), J. Geenen (Wisconsin Center for Advanced Research, Milwaukee, WI), F. Giardiello (Johns Hopkins Hospital, Baltimore, MD), A. Goetsch (nTouch Research, Huntsville, AL), M. Goldberg (Regional Gastroenterology Associates of Lancaster, Evanston, IL), J.L. Goldstein (University of Illinois at Chicago, Chicago, IL), W. Harlan, III (Asheville Gastroenterology Associates, Asheville, NC), R. Hogan (Gastrointestinal Associates, Jackson, MS), M. Kamionkowski (Gastroenterology Associates of Cleveland, Mayfield Heights, OH), M. Kelfer (Fallon Clinic, West Boylston, MA), B. Kerzner (Health Trends Research, Baltimore, MD), K. Kim (University of Chicago Medical Center, Chicago, IL), I. Klimberg (Gastroenterology Associates of Ocala, Ocala, FL), G. Koval (West Hills Gastroenterology Associates, Portland, OR), C. Krone (Advanced Clinical Therapeutics, Tucson, AZ), S.Krumholz (Waterside Clinical Research, West Palm Beach, FL), M.W. Layton (South Puget Sound Clinical Research Center, Olympia, WA), C. Lightdale (Columbia-Presbyterian Medical Center, New York, NY), P.J. Limburg (May Clinic, Rochester, MN), C. Lind (Vanderbilt University Medical Center, Nashville, TN), D. Lipkis (Institute for Health Care Assessment, San Diego, CA), M. Lloyd (Idaho Gastroenterology, Meridian, ID), D. Maccini (Spokane Digestive Disease Center, Spokane, WA), F. MacMillan, Sr. (Pentucket Medical Associates, Haverhill, MA), R. Madoff (University of Minnesota, Minneapolis, MN), A. Malik (Advanced Clinical Research, North Providence, RI), A. Markowitz (Memorial Sloane-Kettering Cancer Center, New York, NY), R. Marks (Alabama Digestive Research Center, Alabaster, AL), C. J. McDougall (Manhattan Associates, New York, NY), P. Miner (Oklahoma Foundation for Digestive Research, Oklahoma City, OK), M. Murphy (Southern Digestive and Liver Disease Institute, Savannah, GA), A. Namais (Gastrointestinal Physicians, Salem, MA), N. Nickl (University of Kentucky Medical Center, Lexington, KY), M. Pochapin (Jay Monahan Center for Gastrointestinal Health, New York, NY), R.E. Pruitt (Nashville Medical Research Institute, Nashville, TN), J Puolos (Cumberland Research Associates, Fayetteville, NC), D.S. Riff (AGMG Clinical Research, Anaheim, CA), R. Roman (South Denver Gastroenterology, Englewood, CO), L. Rubin (New Jersey Physicians, Passaic, NJ), D. Ruff (Healthcare Discoveries, San Antonio, TX), M. Safdi (Consultants for Clinical Research, Cincinnati, OH), J. Saltzman (Brigham and Women's Hospital, Boston, MA), B. Salzberg (Atlanta Gastroenterology Associates, Atlanta, GA), J.A. Sattler (Western Clinical Research, Torrence, CA), P. Schleinitz (Americas Doctors Research, Medford, OR), J. Schwartz (Northwest Gastroenterologists, Arlington Heights, IL), M. Schwartz (Jupiter Research Association, Jupiter, FL), M. Silpa (Gastroenterology Associates of the East Bay Medical Group, Berkeley, CA), D. Silvers (Drug Research Services, Metairie, LA), D. Smoot (Howard University Cancer Center, Washington, DC), S. Sontag (Veterans Affairs Medical Center, Hines, IL), R.J. Sorrell (Gastroenterology Specialties, Lincoln, NE), D. Stanton (Community Clinical Trials, Orange, CA), J. Sturgeon (Americas Doctors Research, Shawnee Mission, KS), J.P. Tracey (Hawthorne Medical Associates, North Dartmouth, MA), T. Werth (Charlotte Gastroenterology and Hepatology, Charlotte, NC), C.M. Wilcox (University of Alabama at Birmingham, Birmingham, AL), R. Wohlman (Northwest Gastroenterology Associates, Bellevue, WA), S. Woods (Gastroenterology Associates of Fairfield County, Bridgeport, CT); United Kingdom: J. Burn (South Cleveland Hospital, Middlesbrough); Australia: H. Ee (Sir Charles Gairdner Hospital, Nedlands, W.A.), M. Korman (Monash Medical Centre, Clayton, Victoria), A. Lee (Concord Repatriation and General Hospital, Concord, NSW), B. Leggett (Royal Brisbane Hospital, Herston, Queensland), F. Macrae (Royal Melbourne Hospital, Melbourne, Victoria), L. Mollison (Freemantle Hospital, Freemantle, WA), N. Yeomans (Western Hospital, Footscray, Victoria), G. Young (Flinders Medical Center, Bedford, SA); Canada: G. Aumais (Hospital Maisonneuve-Rosemont, Montreal), R. Bailey (Hys Medical Center, Edmonton, Alberta), C. Bernstein (Winnipeg Health Sciences Centre, Winnipeg, Manitoba), L. Cohen (Sunnybrook and Women's Hospital, Toronto), C. Dallaire, R. Dube (Centre Hospitalier Universitaire de Quebec, Quebec), D. Morgan (McMaster University, Hamilton, Ontario), T. Sylwestrowicz (St. Paul's Hospital, Saskatoon, Saskatoon), G. Van Rosendaal (University of Calgary, Alberta), S.J. Van Zantan (Queen Elizabeth II Health Sciences Centre, Halifax, NS).