title: Enzyme histochemical study on human thymus and its age change.
abstract: Human thymuses, ranging in age from newborn to 62 years old, were studied enzyme histochemically. The thymic epithelial cells covering cortical surface and bordering vascular areas in the medulla were positive for 5'-nucleotidase, but not for other enzymes. The thymic epithelial cells composing Hassall's corpuscles were positive for acid phosphatase, esterases, beta-glucuronidase, and alkaline phosphatase, regardless of age, but totally negative for 5'-nucleotidase and ATPase. All enzymes examined except for beta-glucuronidase were demonstrated in some of the thymic epithelial cells scattered in the medulla, although the pattern of distribution and the degree of positivity were different by enzymes. These findings suggest that the thymic epithelial cells are composed of functionally heterogenous subpopulations. Acid phosphatase was demonstrated in thymocytes in both cortex and medulla, but 5'-nucleotidase and ATPase were observed in some thymocytes in the medulla of young thymus.
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D000251:Adenosine Triphosphatases / Q000032:analysis; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D004950:Esterases / Q000032:analysis; D006651:Histocytochemistry; D006801:Humans; D007223:Infant; D008875:Middle Aged; D009708:Nucleotidases / Q000032:analysis; D013945:Thymoma / Q000201:enzymology; D013950:Thymus Gland / Q000166:cytology / Q000201:enzymology*
chemical_list: D004950:Esterases; D009708:Nucleotidases; D000135:Acid Phosphatase; D000251:Adenosine Triphosphatases