Differential expression of ecto-5' nucleotidase activity by functionally and phenotypically distinct subpopulations of human Leu-2+/T8+ lymphocytes.

Subsets of Leu-2+/T8+ cytotoxic/suppressor T lymphocytes were isolated by using various methods of purification and were investigated for expression of ecto-5' nucleotidase (5'NT) enzyme activity by radiochemical, cytochemical, and ultrastructural techniques. By using both the radiochemical and the cytochemical methods. T4-OKM1- cells displayed higher 5'NT activity in comparison with the entire T4- subpopulation.

Decreased ecto-5'nucleotidase activity of peripheral blood lymphocytes in human monoclonal gammopathies: correlation with tumor cell kinetics.

Ecto-5'nucleotidase (5'NT) activity of peripheral blood (PB) lymphocytes was determined in 31 patients with serum monoclonal gammopathies (MG). Twenty-one patients had a diagnosis of multiple myeloma (MM), and ten patients had monoclonal gammopathy of undetermined significance (MGUS). The proliferative activity of the bone marrow plasma cells (LI%) was investigated in 28 of these MG patients by means of tritiated thymidine uptake evaluated by simultaneous autoradiography and cytoplasmic immunofluorescence.

Acetylation of polyamines in chicken brain and retina.

Both spermidine and spermine are acetylated in chicken brain and retina. From spermidine, more N1-acetylspermidine than N8-acetylspermidine is formed by both the brain and the retinal cytosol. Km for spermidine is similar with the enzyme preparation of the two tissues, but that for spermine is lower with the retinal preparation.

Regulation of ornithine decarboxylase: studies on the effect of insulin and diaminopropane on transglutaminase activity.

Transglutaminase activity measurements in the liver of insulin- and diaminopropane treated chickens showed that insulin enhances activity in the supernatant, but has no effect on the nuclear fraction. In the absence of exogenous Ca++ ions, both fractions were more active, showing that insulin promotes an increase in the available Ca++ ions. No modification was observed after diaminopropane.

Arginase, ornithine decarboxylase and S-adenosylmethionine decarboxylase in chicken brain and retina.

Arginase, ornithine decarboxylase and S-adenosylmethionine decarboxylase are active in both retina and brain. Activity is higher in cerebellum than in the cerebral hemispheres and optical lobes. Arginase and ornithine decarboxylase are very active in the retina of very young chicks, while S-adenosylmethionine decarboxylase is poorly active.