Eksperimental'naia onkologiia最新文献

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.

When administered subcutaneously, ortho-aminoazotoluene induces predominantly liver tumours in A/HeJ mice but vascular tumours (located mainly in the interscapular brown fat pads) in CC57BR/Mv mice. Liver tumours are more frequent in females, while vascular tumours--in males. Under crossing, the susceptibility to induction of the both types of tumours in male F1 hybrids is inherited intermediately, whereas in females the resistance to induction of vascular tumours predominates.

It has been shown that phosphoprotein p53 may participate in the DNA-synthesis stimulation in the mixed culture of tumour cells and syngeneic embryonic mouse cells (10 days of pregnancy). This effect has been eliminated by the preliminary treatment of embryonic cells in vitro by the monoclonal antibodies to p53 (pAb421) in the model system. A conclusion is drawn that p53-epitopes of embryonic cell surface membrane take part in the formation of the determinant which is recognized by receptors of tumour cells. The stimulation of DNA-synthesis in tumour cells is resulted by this process.

Four monoclonal antibodies (Mabs) of series IGR-1 and IGR-2 to nuclear antigens of neutrophilic granulocytes of human peripheral blood were obtained. Mabs IGR-1 2B8 and IGR-1 6B5 are bound to their specific antigens in the nuclei of all the investigated human cell lines. These Mabs were also specific for metaphase chromosomes of cell lines HL-60 and U-937. Investigations on the ultrastructural level showed that Mabs IGR-1 6B5 reacted with the HL-60 nuclear heterochromatin region. Mabs IGR-1 3D3 and IGR-2 2F1 manifested high specificity only for the nuclei of mature neutrophils and of plasma cells.

Problems of the origin, structure and functions, in the cells and tissues, of the so-called proto-oncogenes (c-onc)--cell genes, homologues and oncogene foreparents (v-onc)--are considered in the review. Up-to-date data are given to show the participation of the main groups of proto-oncogenes in the processes of cell division, proliferation and differentiation. The role of c-onc genes is found to be important for fundamental manifestations of the cell life activity. Special attention is paid to the problem of interrelation of the proto-oncogenes with growth factors and their receptors.

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.