Tissue transplantation as a compensation for deleterious effects of ageing, radiation, diabetes, and craniocerebral trauma.

The presence of blood-brain and blood-ocular barriers allows the transplantation of various biological tissues into the brain and the anterior eye chamber without acute immune rejection. Tissue grafting into the immuno-privileged areas (brain, anterior eye chamber) allows its long-term functioning without immuno-suppression. This method was shown to be effective in compensating for the deleterious effects of ageing, radiation, diabetes, and craniocerebral trauma.

The effect of inhibitors of arachidonic acid metabolism on proliferation and death of tumor cells.

The effect of inhibitors of arachidonic acid metabolism on proliferation and death of tumor P-388 cells in a broad concentration range was studied. Cell proliferation was estimated by the metaphase frequency and the proportion of cells in S phase; cell death was determined from lysis, staining of cells with trypan blue, nuclear damage, percentage of cells with subdiploid DNA and the type of DNA fragmentation. It was shown that low concentrations of phospholipase A2 and lipoxygenase inhibitors stimulated the proliferation of P-388 cells.

The effect of melittin on proliferation and death of thymocytes.

The effect of melittin, an activator of phospholipase A2, on proliferation and death of rat thymocytes in a broad concentration range was studied. Cell proliferation was estimated by the accumulation of colchicin metaphases, necrotic death was determined from lysis and staining of cells with trypan blue, and apoptosis was assessed from the type of DNA fragmentation, the amount of fragmented DNA, and the percentage of cells with subdiploid DNA. It was shown that low melittin concentrations (below 5 microg/ml) stimulate thymocyte proliferation.

Intercellular interactions in the interphase death of irradiated thymocytes.

The effect of the interaction of different types of cells on the interphase death and pycnosis of thymocytes irradiated in vitro was studied. When removed from the thymus suspension of cells with natural killer activity, medullary thymocytes and macrophages did not change the radiation-induced death of cortical thymocytes. On the other hand, postirradiation incubation of cortical thymocytes together with unirradiated thymocytes or with cells of certain other cell lines diminished thymocyte death.

The mechanism of radiation-induced interphase death of lymphoid cells: a new hypothesis.

The interphase death of irradiated rat thymocytes depends on their concentration during postirradiation incubation. The kinetics of pycnosis and cell death determined with the trypan blue exclusion test in the samples with the highest cell concentration (1-2 x 10(7) cells/ml) is consistent with the data available in the literature, whereas the samples with the lowest concentration (2 x 10(5) cells/ml) undergo almost no pycnosis and death after irradiation with doses up to 50 Gy. On the basis of these results, we suggest a new mechanism of interphase death involving an interaction between irradiated thymocytes and the fraction of thymus cells possessing cytocidal activity.

Mechanisms of the radioprotective effect of cysteamine in Escherichia coli.

The values of the oxygen effect (m) and the maximal protective effect of cysteamine (DMF*) were estimated for four Escherichia coli strains: AB1157 (wild type), AB1886 (uvrA), AB2463 (recA), and p3478 (polA). A correlation made between DMF* and m as well as the kinetics of the increase of DMF with oxygen depletion showed that the protective effect of cysteamine is realized by three mechanisms: (i) anoxia achieved by oxygen reduction, with the DMF varying from 2.2 to 4.