Analysis of substances issuing from Zajdela ascitic hepatoma cells after exposure to UV radiation of different wave-lengths. I. Relationship to dose]

The release of substances from the Zaidela ascitic hepatoma cells after irradiation with physiological doses of short-wave (254 nm) and long-wave (300-380 nm) UV light (far and near UV light) has been studied spectrophotometrically. Within the range of 200-520 nm, the absorption spectra of releasing substances show maxima at 215 and 260 nm and are identical to spectra of non-irradiated cells. The amount of substances increases with dose making up, at the maximal alteration, 180-220%, of the amount releasing from non-irradiated cells. Irradiation with far UV light exceeds by one order that with near UV light. The effect of minimum doses is opposite to the action of high doses: the release of substances from irradiated cells is much less.     

Analysis of substances issuing from Zajdela ascitic hepatoma cells following exposure to UV radiation of different wavelength. II. Proton release]

The release of protein from the Zaidela ascitic hepatoma cells following irradiation with physiological doses of short-wave (254 nm) and long-wave (300--380 nm) UV light (far and near UV radiation) has been investigated. The amount of protein increases with dose making, upon the maximal radiation damage, 180 and 2 per cent of the protein against, resp., the protein amount releasing from non-treated cells and the total protein of the intact cell. The far UV light is by one order more efficient than the near UV light. Irradiation of cells with the former and the latter results in the release of high and low molecular proteins, resp. The near UV irradiation brings about heavier releasing of proteins than does the far UV light.     

Antibacterial activity of rifampicin against the causative agents of suppurative, septic diseases]

The antibacterial activity of rifampicin was studied in comparison with other antibiotics with respect to clinical strains isolated from cases with various purulent inflammatory processes caused by Staphylococcus, E. coli, Ps. aeruginose, Proteus. The aim of the study was to define the role of rifampicin in the treatment of the above infections. No rifampicin resistant strains were found among staphylococci belonging to the phenotype carrying the determinants of resistance to 2-8 antibiotics. Rifampicin was less active against gramnegative organisms. High heterogeneity of the microbial population of rifampicin was shown with respect to all microbial strains tested. The rate of the spontaneous mutants was high. The average rate of the mutants was 1-7.7-10-8. The studies on the dynamics of the rifampicin resistance increase in the strains of Staphylococci, E. Coli, Ps. aeruginosa and Proteus showed that the resistance increased after 1-2 passages, which means that one-stage mutation was characteristic rifampicin.     

Destructive changes in the outer perimembrane layers (glycocalyx) of Zajdela ascites hepatoma cells under the action of UV radiation]

Immediately after far (254) nm and near (300--380 nm) UV light in small and moderate doses alcian blue sorption by glycocalix of Zaidela ascitic hepatoma cells decrease, which is indicative of destruction and solubilization. The effect of UV light on the cell surface is compared with the action of trypsin. Contribution of the damage of outer perimembrane layers to the lethal effect of UV light is discussed.     

Study of hematopoietic stem cell pool maintenance in successive transplantations using a quantitative method of assessment]

The ability of transplantable hemopoietic stem cells (HSC) to maintain their pool was studied using successive bone marrow transplantations with quantitative evaluation of hemopoiesis restoring units (HRU) in each transfer. The number of injected HRU increased (3.6-48.6--fold) upon each transfer; however, the normal level could not be attained. The ability fo HRU for further multiplication was exhausted after five transfers. HRU lost totipotentiality after four transfers. The data obtained support the concertion of Kay (1965) that HSC department is a pool of heterogeneous cells, and the property of "stemness" is inversely related to the number of divisions of ancestral cells. Transplantation, being a proliferative stress for the dormant HSCs, thus lowers the stem potential of the whole pool. The experimental data suggest that while dividing stem cell does not have a choice to self-renew or to differentiate into maturing cells, but it really differentiates into HSCs of lower rank.     

A chlorotetracycline fluorescent probe--an indicator of calcium ion binding with calcium-binding proteins

It has been found in in vitro experiments that fluorescence intensity of deionized solution containing a chlorotetracycline fluorescent probe increases insignificantly at the addition of calmodulin of S-100 proteins. Subsequent introduction of Ca2+ into the medium results in the pronounced fluorescence increase depending on Ca2+ concentration. Addition of specific protein blockers--W7 (calmodulin inhibitor) and antibodies to S-100 brought about a decrease of fluorescence. In in vivo experiments on chlorotetracycline-stained neurons of Helix Pomatia ganglia subesophageal complex it has been shown that bringing of antibodies to S-100 and calmodulin significantly decreases the fluorescence intensity of these cells. These data suggest that the chlorotetracycline probe is an indicator of calcium ions binding with calcium-binding proteins both in in vitro and in vivo systems.     

Enhancement of fibroblast growth promoting activity of human blood after its irradiation in vivo (transcutaneously) and in vitro with visible and infrared polarized light

Visible and infrared (IR) irradiation of laser and non-laser sources has a pronounced wound-healing effect promoting tissue repair without hyperproduction of connective tissue elements. This effect develops as a consequence of local and systemic light effects, but many aspects of their mechanism have been yet unclear. In the present work, we have shown that in 0.5 h after irradiation of a small area of the volunteers' body surface with polychromatic visible + IR light (400-3400 nm, 95% polarization, 12 J/cm2) the amounts of PDGF and TGF-beta 1 in the blood serum increase, on average, by 20 and 43%, respectively. This effect is preserved for at least 24 h to be recorded only in volunteers with the initially normal and decreased levels of the growth factors; the initially elevated content of PDGF-AB decreases. Addition of such a plasma (2.5%) to the nutrient medium of primary cultures of human embryonal fibroblasts stimulates cell proliferation, on average, by 10 and 17%, but only in the case if the initial growth-promoting (GP) blood activity was low. Similar changes occur in parallel experiments following irradiation of blood samples of the same volunteers in vitro, as well as at mixing irradiated and non-irradiated autologous blood at the ratio 1:10 (v/v), i.e. at modeling a situation in the vascular bed, when the transcutaneously photomodified blood contacts with the rest of its volume. Similar changes in the blood GP activity under conditions in vitro were recorded as well after 4-9 daily phototherapy sessions. This allows us to suggest that changes in GP activity of circulating blood of the irradiated volunteers may be, to a large extent, the consequence of effect exerted on the blood by small amounts of transcutaneously photomodified blood. The obtained results are discussed in terms of light effect on wound healing and scar tissue formation, with regard to the authors' previous data on much higher GP of the irradiated blood in respect to keratinocytes, the fast decrease in proinflammatory cytokine levels, and the increase in IFN-gamma content.     

Structural characteristics of ionotropic glutamate receptors revealed by channel blockade

The topography of the channel binding site in glutamate receptors (AMPA and NMDA types of rat brain neurons, receptors of molluscan neurons and insect muscle), and in two subtypes of nicotinic cholinoreceptors (in frog muscle and cat sympathetic ganglion), has been investigated by comparison of the blocking effects of mono- and dicationic derivatives of adamantane and phenylcyclohexyl. The channels studied can be divided into two groups. The first one includes AMPA receptor and glutamate receptors of mollusc and insect, and is characterised by the absence of activity of monocationic drugs and the strong dependence of dicationic once on the internitrogen distance in the drug molecule. The second group includes NMDA receptor and both nicotinic cholinoreceptors. Contrary, here the blocking potency of monocations and dications are practically equal irrespective of molecule length. The data obtained suggest that hydrophobic and nucleophilic components of the binding site are located close to each other in the channels of the NMDA receptor type but are separated by approximately 10 A in the AMPA receptor channel.     

The ecology and prevalence of arboviruses on the territory of the Saratov Region

The territorial spread of Tahyna, Batai, Sindbis, West Nile fever and Crimean-Congo hemorrhagic fever viruses throughout the Saratov region in 1998 - 2000 was analyzed. The characteristics of the epizootic activity of the natural foci of these arboviruses in different landscape zones (temperate forest-steppes, steppes and semi-deserts) were calculated. The species composition of small mammals, the natural reservoirs of the causative agents of arbovirus infections, was determined.