Figure 1.

Immunohistochemistry for trypsinogen-1. A: Lack of immunopositivity for trypsinogen-1 (Tryp-1) in a colonic sample at the diagnosis of a pediatric patient with ulcerative colitis who was operated on two years after diagnosis (× 200); B: Immunopositivity for Tryp-1 in the colonic epithelial cells of a diagnostic tissue sample from a conservatively treated patient with seven years follow-up from the diagnosis (× 400).