Arachidonic acid metabolism in growth control of A549 human lung adenocarcinoma cells.

The role of individual eicosanoids of the arachidonic acid (AA) cascade in the growth control of A549 human lung adenocarcinoma cells has been studied. Cyclooxygenase and lipoxygenase metabolites of [14C]AA incorporated were actively synthesized in the cultures of tumor cells with full confluence unaccomplished. In such cultures inhibitors of AA metabolism (indomethacin and esculetin) and also a lipoxygenase metabolite of AA, 15-hydroxyeicosatetraenoic acid (15-HETE), significantly suppressed the incorporation of [3H]thymidine and biosynthesis of prostaglandin E2 (PGE2).

[The role of glycosaminoglycans and proteoglycans in hemopoiesis and the physiological functions of the blood cells].

Literature review as well as own data on the role of glycosaminoglycans and proteoglycans of leukocytes, platelets and hemopoietic microenvironment are presented. These compounds are involved in the storage of lysosomal enzymes, cationic antibacterial polypeptides and other granular constituents of blood cells, take part in mediating of cellular interactions, occurring in hematopoiesis, phagocytosis, immunity and other processes. Due to the capacity to react with many substances, including enzymes, cell growth factors, cytokines, receptors, changing their conformation and biological activity glycosaminoglycans and proteoglycans can take part in regulation of cell adhesion, migration, proliferation differentiation and special functions of various types of hematopoietic and lymphoid cells.

[The use of verapamil in tests for determining the drug resistance of leukemic blasts].

To determine prognostically unfavourable groups of acute leukemia patients, the authors studied the in vitro accumulation of 3H-vincristine (Vcr) and adriamycin (ADR) as well as inclusion of 3H-cytosar (Ara-C) into marrow blast DNA from patients showing different effects of treatment. It was found resistant to induction chemotherapy increases with verapamil addition to culture medium (Vrp+ cells). ADR inclusion into Vrp+ cells was the same as that into Vrp- cells.

[The carcinogenic activity of N-nitroso-N-ethylurea in kidney organ cultures of mice exposed transplacentally to cobalamin coenzymes and folinic acid].

Preneoplastic changes in organ cultures of mouse embryonic kidney (OCEK) under transplacental N-nitrosoethyl urea (ENU) did not increase under the influence of Ado-Cbl. The frequency of focal proliferation in OCEK under transplacental influence of Ado-C bl and ENU was 2.2 times less than the combination of carcinogen with MeCbl (32.

[Comparative evaluation of blast cell proliferation and effectiveness of combined chemotherapy in children with different immunocytological subvariants of acute lymphoblastic and nonlymphoblastic leukemia].

It has been found that kinetic parameters of proliferation in a dominating clone of bone marrow blast cells with Ia-positive and Ia-negative phenotype, as well as with expression of myeloid differentiating antigens (ICO-GM1 and ICO-G2), or in the absence of these antigens, do not significantly differ in children with subvariants MO-M4 of acute nonlymphoblastic leukemia, sensitive and resistant to the therapy. A higher rate of the bone marrow blast cell population growth and a lower effectiveness of the combined chemotherapy have been recorded in children with T-cell and pre-B-cell acute lymphoblastic leukemia as compared to acute lymphoblastic leukemia with the phenotype of blast cells that have only Ia-like or "common" antigens.

[The modifying influence of adenosylcobalamin on the transplacental carcinogenic effect of N-nitroso-N-ethylurea in organ cultures of the kidneys of DBA/2 mice].

Transplacental effect of cobalamin coenzyme, adenosylcobalamin (Adocbl), on the carcinogenic action of N-nitroso-N-ethylurea (ENU) was studied in culture of the mouse embryonic kidney tissue by histoautoradiography. Coenzyme methylmalonyl-CoA-mutase, Adocbl, injected into DBA/2 mice in the prenatal period did not stimulate the proliferative activity of epithelial cells of the embryonic kidney. The treatment with Adocbl did not intensify hyperplastic changes common for the early stages of carcinogenesis.

[Transplacental effect of methylcobalamine on the growth of embryonic mouse kidney tissue in organotypic cultivation].

Transplacental growth-stimulating effect of the Cbl-coenzyme methylcobalamine (MeCbl) was revealed in organ cultures of embryonic kidney tissue in DBA/2 mice. MeCbl improved the survival of embryonic kidney explants and decreased the incidence of degenerative damage in cultures. The frequency of regeneration development was 30%.

[Modifying effect of methylcobalamin in organ cultures of the mouse kidney when administered transplacentally in combination with N-nitrosoethylurea].

The influence of methylcobalamin (MeCbl) on transplacental effect of N-nitrosoethylurea (NEU) was studied in organ cultures of embryonic tissue of DBA/2 mice by the histoautoradiography (3H TdR). A combined transplacental treatment of pregnant mice with MeCbl and NEU produced a 3.3-fold increase in the frequency of focal hyperplastic growth of epithelium as compared to the effect of NEU alone.

[Cellular mechanism of the antileukemic action of quinoline dibromide].

Autoradiography (3H-thymidine) and DNA-cytofluorometry were used to study the effect of quinoline dibromide (QD), a potential inhibitor of cobalamine-dependent methionine synthetase, on the kinetics of cell proliferation of L-1210 mouse leukemia. QD was found to produce the secondary blockade of leukemic cells in the late S-phase of the mitotic cycle. Such a mechanism of QD action promoted the potentiation of antitumor activity of the antimetabolites methotrexate, cytosine arabinoside and 5-fluorouracil during combined chemotherapy.

[Methionine synthetase activity in tumor cells following administration of methylcobalamin and its analog].

Methylcobalamin (10 microgram/kg bw, intramuscularly, on the 3d and 5th days after tumor transplantation) or methylcobalamin chlorpalladat -- MeCbl.PdCl3 (250 mg/kg bw in 2% starch suspension per os on the 2d and 6th days) were given to C57BI mice bearing adenocarcinoma Ca--755. On the 8th day after transplantation the methionine synthetase activity and proliferative pool of tumor cells were estimated.

[Kinetics of the cell proliferation of murine mammary adenocarcinoma under the influence of methylcobalamine].

The mechanism of the stimulant effect of methylcobalamine on the growth of mouse adenocarcinoma 755 was studied. More rapid growth of adenocarcinoma 755 under the cobalamine coentzyme effect is consequent on an increased proliferative pool with the stable parameters of the mitotic cycle and minimal death of tumour cells. Apparently, inhibition of DNA synthesis in the greater S-phase cell subpopulation potentiated the antitumour effect of methotrexate combined with methylcobalamine.

[Effect of methylcobalamin and fluoralkylcobalamins on E. coli 113/3 cell growth and on a primary human embryonic fibroblast culture].

Comparative analysis of the functional activity of several fluoralkylcobalamines was carried out using E. coli 113/3 strain deficient in vitamin B12 and methionine. Difluoro chlor methylcobalamine (CF2Cl-Cbl) exhibited the most distinct inhibitory effect on growth of bacterial cells in the medium with cobalamine.