[1] UNIV BOLOGNA, DEPT GASTROENTEROL, I-40126 BOLOGNA, ITALY
[2] L SACCO HOSP, DEPT GASTROENTEROL & DIGEST ENDOSCOPY, MILAN, ITALY
[3] BOLZANO GEN HOSP, DEPT GASTROENTEROL, BOLZANO, ITALY
[4] POLICLIN UMBERTO 1, DEPT SURG, ROME, ITALY
[5] UNIV NAPLES, DEPT SURG ANAT, I-80138 NAPLES, ITALY
[6] SS ANNUNZIATA CIVIL HOSP, INST MED PATHOL, CHIETI, ITALY
[7] NEW POLYCLIN, DEPT GASTROENTEROL, NAPLES, ITALY
[8] HOSP MAGGIORE, INST CLIN MED 3, MILAN, ITALY
[9] HOSP MAGGIORE S GIOVANNI BATTISTA, DEPT GASTROENTEROL, TURIN, ITALY