[1] Med Univ South Carolina, Charleston, SC 29425 USA
[2] Univ Pittsburgh, Med Ctr, Pittsburgh, PA USA
[3] Indiana Univ Sch Med, Indianapolis, IN 46202 USA
[4] Richmond Gastroenterol Associates, Richmond, VA USA
[5] Univ Michigan, Ann Arbor, MI 48109 USA
[6] Mayo Clin, Jacksonville, FL 32224 USA
[7] St Louis Univ, St Louis, MO 63103 USA
[8] Johns Hopkins Med Inst, Baltimore, MD 21205 USA
[9] Virginia Commonwealth Univ, Richmond, VA USA
[10] Brigham & Womens Hosp, 75 Francis St, Boston, MA 02115 USA
[11] Ohio State Univ, Columbus, OH 43210 USA
[12] Aurora St Lukes Med Ctr, Milwaukee, WI USA
[13] Yale Sch Med, New Haven, CT USA
[14] Univ Chicago, Chicago, IL 60637 USA
[15] Digest Hlth Specialists, Tupelo, MS USA
[16] Univ Florida, Gainesville, FL USA
[17] Univ Alabama Birmingham, Birmingham, AL USA
[18] Dartmouth Hitchcock Med Ctr, Lebanon, NH 03766 USA