[1] CHIBA UNIV, SCH MED, DEPT MED 1, CHUO KU, CHIBA 260, JAPAN
[2] NAGASAKI CHUO NATL HOSP, INST CLIN RES, OHMURA, JAPAN
[3] TORANOMON GEN HOSP, DEPT GASTROENTEROL, TOKYO, JAPAN
[4] KURUME UNIV, SCH MED, DEPT PATHOL 1, KURUME, FUKUOKA, JAPAN
[5] TOKYO WOMENS MED COLL, INST GASTROENTEROL, TOKYO 162, JAPAN
[6] COLUMBIA UNIV, COLL PHYS & SURG, NEW YORK, NY USA
[7] MAYO CLIN, DEPT MED PATHOL, ROCHESTER, MN USA
[8] CHIBA UNIV, SCH MED, CHIBA 280, JAPAN