[1] WASHINGTON UNIV, SCH MED, DEPT INTERNAL MED, DIV GASTROENTEROL, ST LOUIS, MO 63110 USA
[2] WASHINGTON UNIV, SCH MED, CHROMALLOY AMER KIDNEY CTR, DIV RENAL, ST LOUIS, MO 63110 USA
[3] WASHINGTON UNIV, SCH MED, MALLINKRODT INST RADIOL, ST LOUIS, MO 63110 USA