The effect of UV irradiation and of UV-irradiated autologous blood on the functional state of human peripheral blood lymphocytes

The effect of UV irradiation (UVI, 254 nm) and of UV-irradiated autologous blood on the spontaneous and mitogen-induced DNA-synthetic activity of intact lymphocytes has been studied. Lymphocytes were isolated from nonirradiated and irradiated blood, and from the mixture of UV-irradiated blood with the intact one in the volume ratio close to that in the blood stream during UV-irradiated blood autotransfusion (1:10, 1:40, 1:160). It has been shown that UVI of the whole blood caused in some donors the increase in spontaneous DNA synthesis, while in others the decrease or no statistically significant changes were observed. The analysis of the results obtained shows an inverse relation of the UVI effect to the initial level of spontaneous DNA synthesis (r = -0.68). In contrast to direct UVI effect, an addition of UV-irradiated blood to the autologous intact one resulted in an increase in spontaneous DNA synthesis in lymphocytes of all the samples examined. A 7-day cocultivation of lymphocytes, isolated from irradiated and nonirradiated blood samples, revealed a 1.8 times increase compared to the calculated value. The mitogen-induced DNA synthesis has a low sensitivity to UV rays, since the mitogens and the irradiation of optical range have presumably the common targets. It is assumed that photomodification of HLA-D/DR antigens can be a trigger mechanism for activation of immunocompetent cells by UVI.     

Conditioning and sensitization in the edible snail: the neurophysiological and metabolic characteristics]

Electrophysiological parameters and bound calcium (Ca(b)) level dynamics during sensitization development or conditioning of food aversion were studied in the command neurons of defense behaviour in the snail Helix lucorum. Responses evoked by a testing sensory stimulus were facilitated 50-60 min after the first sensitizing stimulation, while conditioned responses appeared 80-90 min after the first conditioning. It was the most essential electrophysiological difference between the long-term sensitization and conditioning. Analysis of the Ca(b)) dynamics in the neurons showed significant differences in calcium-dependent metabolism during the sensitization and conditioning, likely underlying the electrophysiological differences.     

The development of the hemopoietic system: colony-forming splenic units in mouse embryogenesis

Localization and time of appearance as well as dynamics of quantitative changes of splenic colony-forming units (CFU-S) in mouse (C57BL/6 X CBA)F1 embryos were studied. Cells taken from the whole embryo (day 8), yolk sac and embryo per se (day 9), and also liver (day 10) were injected into the lethally irradiated syngenic mice. 7-8 days after the injection the spleens were fixed and the number of macrocolonies was counted. Statistically significant number of CFU-S was detected starting from day 10 of development, first in the embryo (30-33 somites), then in yolk sac and blood (37-38 somites) and liver (after the 40 somites stage). Rapid increase of CFU-S number during days 11-12 (two-fold increase in about 4.6 hours) suggest that not only active proliferation of CFU-S but also maturation of CFU-S precursors take place.     

Mechanisms of the bactericidal action of hydrogen peroxide

The comparative study of some aspects of the bactericidal action of H2O2 on Escherichia coli, Staphylococcus aureus and Bacterium subtilis wild-type cells and their mutants with lesions in the systems of the reparation of DNA has been carried out. Hydrogen peroxide has been shown to cause disturbances in the structure and permeability of the cell wall, the cytoplasmic membrane, as well as to induce ribosomal lesions and the ruptures of bacterial DNA. The activity of the systems responsible for the reparation of lesions in the cell genome plays an important role in the resistance of bacteria to H2O2.     

Excitatory effect of tuftsin tetrapeptide on the activity of white rats

Studies on male white rats have shown that tuftsin (trelys-pro-arg) enhances the locomotion in animals as disclosed by a series of the behavioral tests. The effect is dose-dependent: a dose of 50 microgram/kg did not change any of the test parameters, while that of 150 microgram/kg induced a short-term elevation of locomotion measured with an "Animeks". Administration of tuftsin in a dose of 300 microgram/kg led to the enhancement of the animals' locomotion as measured with the "Animeks", to the increased "open field" running time and to the reduced latent period of the reaction during the training in a T-shaped maze. Also, this dose of the peptide relaxed the reactions associated with fear. It is assumed that the effects observed are consequent on the stimulant action of tuftsin on the body of white rats.     

Quantitative analysis of survival during syngeneic and semisyngeneic bone marrow transplantation: relation of the protective effect and the ability to induce secondary disease as affected by differences in the major histocompatibility locus

The protective effect of bone marrow (BM) with both syngeneic and semisyngeneic transplantation is an exponential function of the number of transplanted cells. The regression coefficient in the logarithmic equation represents a fraction of hemopoiesis repair units (HRU). The quantitative analysis of the remote death of recipients of the parents' BM shows that the secondary disease (SD) is caused by other than HRU cells which is in agreement with the data obtained by other methods. The fraction of BM cells that induces SD is lower than the fraction of HRU. This helps to find an optimum BM dose range within which the risk of the SD-induced death is minimized.     

Morphofunctional characteristics of enzyme activity of the muscles in ontogenesis and after physical load

By means of histochemical methods using cytospectrophotometer in femoral muscles of white rats 1-, 3- and 12-month-old enzymatic activity of anaerobic and aerobic cycles has been estimated. The greatest changes occur after 20 days of physical load in 1- and 12-month-old animals. The semitendinous muscle (ventral origin), consisting mainly of red muscle fibers, works chiefly in aerobic regime and possesses a more manifested succinate dehydrogenase activity, and the quadriceps muscle (dorsal origin) consists principally of white fibers and its lactate dehydrogenase activity changes more noticeably.