RectumBiopsyColitis, UlcerativeHirschsprung DiseaseProctitisIntestinal MucosaRectal DiseasesProctocolitisCrohn DiseaseColonic Diseases, FunctionalSigmoidoscopyAminosalicylic AcidsSpirochaetales InfectionsBiopsy, NeedleConstipationColonColitisIntestinal DiseasesDiarrheaRectal NeoplasmsHistocytochemistryCystic FibrosisFecesChloridesImmunohistochemistryInfant, NewbornImage-Guided BiopsyBiopsy, Large-Core NeedleBiopsy, Fine-NeedleSentinel Lymph Node Biopsy