Eksperimental'naia onkologiia最新文献

A degree of destruction of tumour cells after their inoculation to a syngenic recipient correlates positively with sensitivity to the lytic effect of macrophages. A clear-cut participation of macrophages in elimination of tumours cells can be detected 8 h after their inoculation.

The inhibiting activity of bone marrow fibroblasts and their ability to sustain survival of granulocytic cell precursors have been studied in patients with chronic myelocytic leukemia, chronic lymphoproliferative disorders, acute leukemia, myelodysplastic syndrome. Fibroblast conditioned medium inhibits proliferation of granulomonocytic precursors stimulated by leucocyte feeder layer or leucocyte conditioned medium. The effect depends both on the presence of monocytes and the specificity of the disease. The inhibitory effect is related with long-ranged factors. Bone marrow fibroblasts are able to sustain survival of hemopoietic precursors via humoral and cell-cell mechanisms. The regulatory role of bone marrow fibroblasts in hemopoietic disorders is discussed.

Frequency and spectrum of chromosomal aberrations were studied in hemopoietic cells of Wistar rats myeloid leukaemia induced by the prolonged exposure to tritium oxide. Differences in quantitative and structural damages of chromosomes were revealed by the cytogenetic assessment of eighteen rats with acute myeloid leukaemia (AML) and six rats with chronic myeloid leukaemia (CML). The most characteristic chromosomal aberrations for AML appeared to be rearrangements in chromosomes 1-3. In CML translocations by one of chromosomes 15-20 coupled with defects in the groups of chromosomes 5-10 seemed to be nonrandom.

Samples of tissue from malignant fibrous histiocytoma of rats induced by subcutaneous injection of paraffin pill-enclosed DMBA were studied for localization of acid phosphatase and non-specific esterases (15 samples) and cell ultrastructure (10). Tumours showed cellular heterogeneity consisting of 5 types of cells: histiocyte-like, fibroblast-like, giant multinuclear xanthomatous and undifferentiated. Acid phosphatase and non-specific esterases were found both in histiocyte-like and fibroblast-like cells which means that those enzymes are not the specific markers of tumors arising from monocytic-macrophagal system. Histochemical and ultrastructural features of experimental malignant fibrous histiocytoma were similar to those of its human analogue.

Seven clonal sublines of the strain of syrian hamster embryo cells transformed in vitro by the Rous sarcoma virus were obtained. All clones possessed both high resistance to damage by hydrogen peroxide and a capacity to release E-type prostaglandins in response to contact with NK-cells in vitro. The clones did not differ from each other and from the parent population in respect to these qualitative properties. Possible relation between these two properties and their role in resistance of transformed cells to cytotoxic activity of macrophages, neutrophils and NK-cells and thus to their ability to survive in vivo are discussed.

The results obtained provide evidence concerning the nature of the Hodgkin and Reed-Sternberg cells. The data based on application of new methods developed during last years such as different enzymo- and immunocytochemical techniques, monoclonal antibody and lectin application and molecular studies of gene rearrangement are presented.

The architecture and fields of application of the expert systems in oncology are described. These systems allow systematization, developing and realizing the approximate knowledge, heuristics and algorithms of the expert-oncologists by the computer systems for solution of optimization problems of diagnosis and treatment of cancer patients. Principles of the functioning of expert systems are considered through the examples of solutions of concrete problems in oncology. Intellectual possibilities of the man-machine interaction under clinical conditions are discussed. The vistas of technological development of expert systems in oncology are evaluated.

The data on carcinogenic activity of certain metals and their compounds to humans and experimental animals are reviewed. Cellular uptake and intracellular distribution of metal compounds, metal-induced genotoxicity in different short-term tests are described. Specific lesions of DNA produced by carcinogenic metals, the influence of metal ions on the cell growth, DNA replication and DNA repair involved in mutagenesis and oncogenesis are under discussion. Mechanisms of metal carcinogenesis are studied to a less extent as compared with organic carcinogenesis.

Proliferative activity and differentiation levels of lymphocytes of lymph nodes and peripheral blood of practically healthy people and patients with chronic lymphocytic leukemia have been studied using the present physicochemical methods (autoradiography with labelled DNA and RNA precursors, microspectrocytometry, NMR spectroscopy, kinetic formaldehyde method, etc.). The following points have been stated: stage character of changes in normal and leukemic cells, differences in synthesis of nucleic acids in different periods of the cell cycle in norm and under chronic lymphocytic leukemia, proliferation peculiarities of lymphocytes in lymph nodes and in blood, presence of DNA defects in the process development, changes in lipids of lymphocytes and blood plasma at early stages of the disease and in the process of its development.