The removed colorectum was gently flushed withsaline to remove any fecal contents, opened longitudinally,and fixed in 10% neutralized formalin. After fixation, eachcolon was rinsed in PBS, stained with 0.2% methyleneblue, and microscopically observed. Identification ofACF was carried out according to the criteria describedpreviously (McLellan et al.,1998), and the amount of ACFformation was determined