[Levels of complement components in plasma of onco-hematologic patients with defective hemopoiesis]. / Soderzhanie komponentov komplementa v plazme onkogematologicheskikh bol'nykh pri nedostatochnosti gemopoéza.

Immunochemical assay using monoclonal antibodies was carried out to determine levels of a number of complement components (C3 and its derivatives-C4 and C5) and immunoglobulins (lg) in plasma of patients with onco-hematological diseases involving defective hemopoiesis: leukemia, myelodysplastic syndrome (clonal diseases) or aplastic anemia (delayed clonal disease). The most significant disorders were registered in the concentrations of component C3 and its derivatives. In acute leukemia, the nature and extent of C3 splitting was found to depend on disease while Ig level-on stage. Myelodisplasia usually involved a 2-3-fold decrease in C3 level matched by a rise in the concentrations of its derivatives-C3-like form and C3a fragment. Reduced C3 levels matched by increased ones of Ig were observed in some cases of aplastic anemia. It is suggested that disturbances in complement component level may cause changes in cascade reactions of the complement in onco-hematological patients and thus indirectly influence immune response regulation processes.

[Results of the study of the activity of bone marrow nucleolar organizers in patients with multiple myeloma]. / Rezul'taty izucheniia aktivnosti iadryshkovykh organizatorov kletok kostnogo mozga bol'nykh mnozhestvennoi mielomoi.

Data obtained from karyotyping and estimation of nucleolar organizer (NO) activity in bone marrow cells from 9 patients with multiple myeloma (MM) and from 8 donors are presented. Chromosomes of the 14th and 1st pairs in patients with MM are confirmed to be more frequently involved in rearrangements. It is proved that activity of NO in myeloma cells is rather high as compared to that of erythroid and granulocyte cells, that is associated with their participation in paraprotein synthesis.

[Metabolism of nucleotides and RNA in leukocytes in chronic myeloleukosis]. / Obmen nukleotidov i RNK v leikotsitakh pri khronicheskom mieloleikoze.

Biosynthesis of purine and pyrimidine nucleotides was distinctly increased in leukocytes of patients with chronic myeloid leukosis, involving mainly the reutilization of preformed nitrogenous bases and nucleosides. An increase in the rate of 14C-orotate and 3H-uridine incorporation into the pyrimidine pool of myeloid leukosis cells correlated with stimulation of uridine kinase and orotidine monophosphate pyrophosphorylase, catalyzing biosynthesis of pyrimidine nucleotides in the reutilization pathway and de novo, respectively. The system of adenosine deaminase, providing the high rate of adenosine incorporation into the nucleotide pool, was apparently responsible mainly for the rate of reutilization synthesis of purine nucleotides in normal and leukemic leukocytes. Synthesis of RNA in leukocytes of patients with chronic myeloleukemia was increased mainly due to consumption of nucleotides formed via the reutilization pathway.

[Effect of adenosine on synthesis of pyrimidine nucleotides and RNA in normal lymphocytes and under conditions of chronic lymphoid leukosis]. / Vliianie adenozina na sintez pirimidinovykh nukleotidov i RNK v normal'nykh limfots takh i pri khronicheskom limfoleikoze.

Effect of exogenous adenosine on synthesis of pyrimidine nucleotides and RNA was studied in lymphocytes of the patients with leukemic form of chronic lymphoid leukosis. In presence of adenosine lymphocytes were incubated in mixtures containing the precursors--2,3-2(3)H-aspartic and 2-14C-orotic acids as well as 5-3H-uridine. Effect of adenosine on the activity of key enzymes of pyrimidine nucleotide synthesis (orotidine monophosphate pyrophosphorylase and uridine kinase) was studied. The enzymatic activity was estimated using radiochemical procedures in extracts of lymphocytes stored at -20 degrees after acetone drying. Adenosine similarly inhibited synthesis of pyrimidine nucleotides and RNA in normal and leukemic leukocytes. One of the mechanisms, by means of which the inhibitory effect of adenosine was realized, was related to the enzymatic activity of orotidine monophosphate pyrophosphorylase and uridine kinase.

[Coordination of the main and reutilization pathways of nucleotide biosynthesis in the lymphocytes in leukemia]. / Koordinatsiia osnovnogo i reutilizatsionnogo putei biosinteza nukleotidov v limfotsitakh pri leikoze.

Coordination of these two pathways of nucleotide synthesis in leukocytes under chronic lympholeukosis was studied using incorporation of 14C-orotic acid and 14C-uridine into uridine mono-, di- and triphosphates and also into RNA. Simultaneously, activity of the key enzymes, participating in metabolism of orotic acid and of uridine, was measured: OMP-pyrophosphorylase /EC 2.4.2.10, orotidine-5'-phosphate: purophosphate phosphorybosyl transferase/ and uridine kinase /EC 2.7.1.48, ATP: uridine-5'-phosphotransferase/. The reutilizational pathway of pyrimidine nucleotide synthesis was distinctly activated. At the same time there was only a slight increase in the main pathway of their synthesis in lymphocytes in leukemic form of cronic lympholeukosis. Activities of OMP-pyrophosphorylase and uridine kinase were increased by 30%. An impairment in the coordination of the rates of both pathways of pyrimidine nucleotide synthesis was related to inhibition of OMP-pyrophosphorylase caused by and increase in uridine nucleotide pool.

[Alteration of leukocyte AMP- and IMP-pyrophosphorylase stability in leukemia]. / Izmenenie termostabil'nosti AMF- i IMF-pirofosforilazy leikotsitov pri leikozakh.

Effect of thermic treatment and of pre-incubation with phosphoribosyl pyrophosphate on activity of AMP- and IMP-pyrophosphorylases were studied in leukocytes under chronic forms of limpho- and myeloleukoses. AMP-pyrophosphorylase from leukemia leukocytes was inactivated after heating up to 65 degrees, which, at the same time, as distinct from the enzyme of normal leukocytes, proved to be reversibly reduced after incubation of the heated cell extracts with phosphoribosyl pyrophosphate. IMP-pyrophosphorylase of leukocytes was activated at this temperature; the activation of the enzyme was 15--20% higher in leukemic leukocytes than in leukocytes of healthy donors. The data obtained demonstrate the increased thermostability of purine nucleotide pyrophosphorylase from leukemic leukocytes, which is apparently due to conformational peculiarities of the enzyme molecules.