Activity of epimerases in in vitro cultured fibroblasts.

The process of collagen and proteoglycan synthesis in the in vitro cultured fibroblasts was studied by four original histoenzymological methods: UDP-glucuronic-5-epimerase, hydroxyproline epimerase, UDP-4-epimerase and UDP-N-acetyl-glucosamine epimerase. The process of epimerasization varied in terms of the cell growth stages. Synthesis of collagen and proteoglycans developed in the cells of the same culture but with various intensities in different cell groups.

Histochemical study of leucine aminopeptidase in leukemia.

By means of a histochemical method, the leucine aminopeptidase activity was studied in human normal and leukemic peripheral blood. Before administration of cytostatics the enzymic activity was high in the cytoplasm of blasts and in the nuclei of segmented cells. After therapy the activity of leucine aminopeptidase in blasts decreased, while in polymorphs it became negative in nuclei and positive in their cytoplasm.

Histoenzymatic activity of leucine aminopeptidase in normal bone marrow cells.

Human, monkey, cat and rat bone marrow cells were studied for the histochemical localization of leucine aminopeptidase activity. The granulocytes have a weak enzymic activity in the immature cells and a very strong one in the differentiated cells. The lymphopoiesis is characterized by a strong reaction in the lymphoblasts and different degrees of the enzyme activity in the lymphocytes.