Number of mast cells in the lesional tissue from eight patients with UC. The number was compared between active stage and remission in the same patients. In addition, the number was compared between the lesions and adjacent healthy tissues in nine healthy volunteers who visited our clinic for annual routine physical examination, which comprised the healthy controls. Data were analyzed with non-parametric Kruskall-Wallis and Mann-Whitney tests. Collated specimens were analyzed with Wilcoxon test for non-parametric data, Statistical significance between the groups as indicated at .