Eksperimental'naia onkologiia最新文献

Dextran-ferrite (DF) was injected via the femoral artery to the dogs and followed by local magnetization (induction 0.3 T, grade 0.024 T/cm). It has been shown that the local retention of the iron in some tissues of the leg was 3-5 times as high as the control. The magnetization did not increase the local retention of the iron after intravenous injection of DF to mice and rabbits.

A modifying influence of ortho-cresol (o-cresol) on the carcinogenic effect of benzo(a)pyrene (B(a)P) in their combined peroral administration to CC57Br mice has been revealed. During the simultaneous administration of the o-cresol (1 mg) and B(a)P (1 mg) the rate of tumours, their multiplicity index, the degree of malignancy increased and the latent period shortened. In case of o-cresol administration before or after B(a)P (in the same doses) the decrease of carcinogenic effect has been revealed. In case of simultaneous administration of 10 mg of the o-cresol and 5 mg of the B(a)P the tumor incidence did not change in comparison with the animals of the control group which received only B(a)P. But their progression was hampered which was confirmed by a decrease of the malignancy rate, frequent occurrence and prolongation of the period of the malignization beginning.

Water solutions of adriblastin, dactinomycin, rosevin, methotrexate, cisplatin, sarcolysine, rubomycin, cyclophosphamide, 5-fluorouracil or ftorafur were combined with dextran ferrite. The obtained compositions were injected i.p. to BDF1 mice 24 hours after they were inoculated with one million of murine P388 leukemic cells. Antitumor activity was fully retained for each of these agents in combination with dextran ferrite.

Hepatocytes in cell culture have been studied for their sensitivity to mitogenic effect of the epidermal growth factor, epidermal growth factor and insulin, 10% of cattle blood serum after hyperthermia. It is established that heat shock (43 degrees C, 90 min) induces hypersensitivity of hepatocytes to the mentioned mitogens, its maximum being observed 20-24 h after hyperthermia and coinciding in time with the development of thermotolerance and intensification of protein biosynthesis after the heat shock 68, 70, 94 kD.

Chromosomal damages and their dynamics in blood lymphocytes of mongrel white L10 rats treated (once) intravenously with nitrosomethyl urea (NMU) at a dose of 50 mg/kg have been analyzed. A direct correlation is revealed between carcinogenesis, chromosome aberration level in somatic cells, polyploid and hyperaneuploid cell frequency 24 hs after the NMU treatment and in the precancerous period. An increase of hyperaneuploid and polyploid cells in the organism can serve as a prognostic factor of carcinogenesis.

The biological effect of 211At alpha-particles has been investigated using the Chinese hamster fibroblasts and Ehrlich carcinoma cells growth in vitro. The mean energy of 211At alpha-particles is 6.8 MeV, LET in tissue is 70-160 keV/microns; the half-life period of decomposition of 211At is 7.2 h. The end-points used were a decrease in the mitotic activity, an elevation of the number of degenerating cells, cell with chromosome aberrations and the cell survival. The RBE of alpha-particles in comparison with 60Co gamma-rays is close to 3.

The cell chemiluminescence method was used to demonstrate the ability of asbest and zeolite dusts from 8 deposits of the USSR to induce generation of free oxygen radicals in the phagocytosing cells suspension. It has been found that asbest and zeolite (0.01 and 0.05 mg/ml) increase levels of cells with chromosome aberrations in human cell cultures. The cytogenetic effect of asbest was inhibited by superoxide dismutase (50 mg/ml). The damaging effect of zeolite was decreased by the pharmacological drug bemithyl (0.007-0.07 mM) and completely eliminated by catalase (20 mg/ml). The results obtained indicate that mutagenic effect of dust particles of asbest and zeolite is mediated by oxygen radicals.

The data from literature on chromosome abnormalities in various subgroups of the myelodysplastic syndrome (according to FAB-classification) are presented. Special attention is paid to information about changes in the number and structure of chromosomes during the disease and their prognostic significance. The relation of definite chromosome aberrations to the clinical course and prognosis of the disease, in particular to its transformation into acute leukosis is under discussion.

Pharmacokinetics of the antitumour agent 14CO-dimetinur (100 mg/kg) after oral administration to the intact mice and those with solid leukemia P 388 is characterized by its rapid delivery to organs and tumours with the achievement of maximum radioactivity 5 hours later and the further gradually decline during 4 days. The increased accumulation of the 14CO-products in kidneys and their retarded output from the brain and lungs against a background of the relatively equal distribution of radioactivity between other tested organs have been established. The same level of carbamoylated products in large tumours (the 16th day after leukemia transplantation) as well as in small tumours (the 9th day after inoculation) is in agreement with the conservation of the initial marked inhibitory effect of the drug against advanced tumours.

Mice bearing Ehrlich carcinoma cells received one 80 mg/kg dose of DFMO. After 20 hours the cells were extracted from the peritoneal cavity and separated by means of sedimentation of 1 g in saccharose gradient into 9 fractions depending on the mitotic cycle phase. The content of polyamines in the cells of each fraction was detected by the fluorescent method using fluorescamine. It was shown that the tumor cells during G1 phase mitotic cycle (13-15% cells blocked) and especially cells in the 1st half of S-phase (19-23% cells blocked) were most sensitive to inhibitory effect of DFMO.