[1] Johns Hopkins Univ, Sch Med, Baltimore, MD USA
[2] Virginia Commonwealth Univ, Med Ctr, Richmond, VA USA
[3] Beth Israel Deaconess Med Ctr, Boston, MA 02215 USA
[4] Univ Penn Hlth Syst, Philadelphia, PA USA
[5] McCone Endoscopy Ctr, Alexandria, VA USA
[6] Clin Ctr Liver Dis, Dallas, TX USA
[7] Thomas Jefferson Univ, Philadelphia, PA 19107 USA
[8] Brooke Army Med Ctr, Ft Sam Houston, TX 78234 USA
[9] Schering Plough Res Inst, Kenilworth, NJ USA
[10] Duke Clin Res Inst, Durham, NC USA