[1] Georgetown Univ, Sch Med, Dept Gen Surg, Medstar Washington Hosp Ctr, Washington, DC USA
[2] Medstar Georgetown Univ Hosp, Dept Gastroenterol, Washington, DC USA
[3] Medstar Georgetown Univ Hosp, Dept Pathol, Washington, DC USA
[4] Georgetown Univ, Medstar Washington Hosp Ctr, Sch Med, Dept Gen Surg,Div Thorac Surg, 110 Irving St,NW G253, Washington, DC 20010 USA