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Under hypoxic conditions, aminolevulinic acid-induced accumulation of porphyrin pigments and increase in heme content was observed in bone marrow mesenchymal stem cells. The expression of transferrin receptor CD71 responsible for Fe(2+) transport into the cell was also enhanced. Blockade of porphyrin-transporting protein ABCG2 with fumitremorgin C under conditions of normoxia and hypoxia induced accumulation of porphyrin pigments; in hypoxia, these changes were more pronounced.

The levels and rates of accumulation of porphyrins in lymphoid cells and bone marrow cells treated with exogenous 5-aminolaevulinic acid (ALA) were studied. The dependence of the quantity of porphyrins accumulated in cell on ALA concentrations in the medium had maximum at 0.7-1.0 mM ALA for all the cell types studied (splenocytes, thymocytes, peripheral blood lymphocytes and bone marrow cells). The rate of accumulation of uro-, copro- and protoporphyrins depended on cell types. The lowest and the highest levels were found in splenocytes and highest in bone marrow cells respectively. It is suggested that photodynamic therapy employing ALA is potentially dangerous for blood cells.

It was demonstrated that fibroblast growth factor bFGF influences the process of heme synthesis, the proliferation activity and viability of bone marrow mesenchymal stem cells in culture under hypoxic conditions. The addition of fibroblast growth factor bFGF (7 ng/ml) to the medium under above conditions led to the accumulation of aminolevulinic acid--an early porphyrin and heme precursor, an increase in CD 71 expression--a transferrin receptor, and also a decrease in porphyrin pigments and heme contents--a late precursor and end products of heme synthesis, respectively. It was found that cultivation of the cells under hypoxic conditions and bFGF is an optimum to maintain high viability and proliferation capacity of the mesenchymal stem cells.

The influence of FGF2 on the efficiency of cardiomyocytes differentiation of mesenchymal stem cells (MSC) of bone marrow induced by 5-azacetidine (5-aza) was studied. The effect of FGF2 developing by the 14th day after the combined action of a differentiating agent and growth factor was manifested in an increase in Mef2A, Mef2D and gene transcription and a rise of ionized Ca2+ concentration in cytoplasm keeping cell viability and proliferation activity. In the presence of FGF2 this approach provided cardiomyogenesis and the increase in the formation of early precursors of cardiomyocytes.

This study was designed to investigate the dose-rate dependent effects of ionising radiation on endothelium- and NO-mediated reactivity of aorta and coronary vessels. Rats were exposed to acute ((137)Cs, 9 x 10(-4) Gy s(-1), 18 min) and chronic ((137)Cs, 2.8 x 10(-7) Gy s(-1), 41 days) radiation in 1 Gy dose. Acute irradiation transiently increased coronary flow in eNOS-activity-dependent manner on day 3 after exposure. In striking contrast, chronic irradiation caused a significant depression of coronary flow even on day 90 after irradiation and abolished the effects of NO-synthase inhibitor N-nitro-L-arginine methyl ester (10 micromol l(-1)). Furthermore, low intensity radiation strongly diminished the vasodilator properties of NO-donor sodium nitroprusside (5 micromol l(-1)). A similar pattern was observed in aortic rings. Endothelium-dependent vasodilation was increased on days 3 and 10 after acute irradiation, but strongly inhibited following chronic exposure for the entire post-radiation period. This was accompanied by a diminished vasodilator response to NO-donor on days 3, 10 and 30 of post-radiation but not on day 90. The data suggest that ionising radiation in 1 Gy induces changes of aortic and coronary vessels reactivity depending on the dose-rate and the interval after exposure.

The influence of cytokine LIF (Leukemia Inhibitory Factor) on the viability, and proliferation of mouse R1 line embryonic stem cells (ESC) and their distribution by cell cycle stages has been investigated. LIF (5-20 ng/ml) increased growth of colonies and maintained high proliferative and pluripotent properties of R1. LIF was also involved into the inhibition of spontaneous cell differentiation and apoptotic cell death; it also decreased the rations of S/G2+M cell cycle and doubling-time of cell population.

The effect of the stem cell factor on the state of membranes and functional activity of mouse embryonic stem cells cultivated in LIF (Leukemia Inhibitory Factor) cytokine-free and LIF-containing media has been studied. It was shown that the stem cell factor induces changes in the viscosity of membrane lipid bilayer and increases the respiration rate, the ATP level, and the proliferation activity of embryonic stem cells. An intricate character of the LIF-dependent modification of biological effects of the stem cell factor was revealed.

On simulating infection caused by different herpes simplex virus type 1 (HSV-1) variants responsive and unresponsive to the drugs acyclovir and phosphonoacetic acid in the cultured Vero and C6 cells has revealed the higher ability of target cells to accumulate 5-aminolevulenic acid (ALA)-induced endogenous porphyrins, which determines the selectivity of their photo damages. Optimal conditions have been defined for all the studied HSV-1 variants to show a virus-inhibiting effect upon photodynamic exposure of infected and ALA-treated cell cultures.

Endothelium- and NO-dependent relaxation of aortic segments and basal coronary flow and response of coronary vessels to exogenous NO in the Langendorff-perfused rat hearts were examined on the 3rd, 10th, 30th and 90th days following whole body irradiation in 1 Gy dose with different dose rate. NO-mediated elevation of coronary flow and increased aortic endothelium-dependent vasodilation were found at the early stage after acute irradiation (137Cs, 9 x 10(-4) Gy/s), while vascular reactivity to exogenous NO was not changed. Chronic irradiation (137Cs, 2.3 x 10(-7) Gy/s) significantly impaired endothelium-dependent relaxation within whole experimental period and decreased NO component of basal coronary flow at the 3rd, 10th and 90th day. It was associated with attenuated reactivity to NO-donor in aorta one month after irradiation and in the coronary vessels--shortly after irradiation. In the delayed period endothelial dysfunction and the diminution of NO-dependent coronary flow were mediated by selective impairment of NO synthesis/release. Decreased survival rate of the lethally-irradiated Nwnitro-L-arginine methyl ester-treated animals revealed radiosensitizing properties of NO synthase inhibition. The data obtained indicate the involvement of NO in the alterations of vascular reactivity depending on the dose rate and on the interval after the irradiation.

The postradiation changes of constriction effects of angiotensin II (Ang II) and angiotensin I (Ang I) on isolated preparations of thoracic aorta young and old rats which underwent gamma-irradiation in dose 1 Gy (137Cs, 9 x 10(-4) Gy/s) were investigated. It has been found, that the aging leads to the alteration of angiotensin receptors, which appears as changes in their density and/or sensitivity to action of agonist. With increase of age the activity of angiotensin-converting enzyme (ACE) in the wall of aorta is oppressed, and as a result, the level of local formation of Ang II and the constriction, caused by it are reduced. The inhibitory influence of endothelium on vasoconstriction effects of Ang II and Ang I in ontogenesis does not change. The influence of gamma-radiation in a dose of 1 Gy modifies the functional activity of the local vascular renin-angiotensin system (RAS): the sensitivity and/or density of angiotensin receptors and the activity of ACE increased the dilatation influences of endothelium were oppressed mainly for account of easing the synthesis of NO. The duration of postradiation infringements of functional activity of local vascular RAS in many respects are determined by the stage of ontogenic development of irradiated organism.

The composition of submerged mycelium of Lentinus edodes, grown in laboratory fermenters, has been studied. The mycelium contained 23-24% proteins, 8-9% lipids, up to 1800 mg% phenolic substances, and a significant amount of inorganic substances, including calcium and iron. The fungus produced up to 5.0% intracellular and 3.5-4.0 g/l extracellular polysaccharides. The submerged mycelium stimulated the development of humoral immune response elicited by sheep red blood cells.

The study of isolated segments of aorta has shown that prolongated exposure of rats to gamma-radiation with 50 cGy dose (with a dose rate of 2.8 x 10(7) Gy/s) causes the decrease in endothelium-dependent dilatation responses to M-cholinoreceptors stimulation. During oxygenation the post-radiation changes are displayed within one month, and under functional loads, specifically, during perfusion by hypoxic and anoxic solutions--in more remote terms of the post-radiation period.

Membranotropic amphiphilic chromophore merocyanine 540 sensitized photodynamic inhibition of drug-resistant and sensitive variants of type I herpes simplex virus in cultured Vero cell. Optimal conditions of photodamage to virus particles and infected cells were determined (merocyanine 540 concentration 1 microM, illumination dose 32.5-65.0 kJ/m(2), exposure at early stages of infection). Infected cells actively bind the photosensitizer, which explains their selective photodamage.

The study of heart isolated by Langendorf's method has shown that the prolongated gamma-irradiation of euthyroid rats in 1.0 Gy dose (2.8 x 10(-7) Gy/sec) causes the decrease in contraction ability, myocardium relaxation and functional response of heart to the stimulation of beta-adrenergic receptors, and the increase in myocardium reaction to the stimulation of alpha-adrenergic receptors. The irradiation of hypothyroid animals leads to more significant and long changes in contraction function of heart and its adrenergic regulation.

The study of heart isolated by Langendorf's method has shown that the prolonged gamma irradiation of rats with 1.0 Gy dose (2.8 x 10(-7) Gy/sec) causes the decrease in contraction and relaxation ability, of myocardium, reduces functional response of heart to the stimulation of beta-adrenergic receptors, and increases of myocardium reaction to the stimulation of alpha-adrenergic receptors.

Nonstimulated and isoproterenol, GTF, GITF, NaF stimulated activities of the adenylate cyclase in sarcolemma in white rats' myocardium was studied after two weeks of hypokinesia. As was established, in restrained animals the sensitivity of adenylate cyclase to the specified agents was increased and transition to the bimodal GTF regulation took place. It is hypothesised that involvement of membrane-bound Gi-proteins in the adrenergic effects on cardiomyocytes is one of mechanisms of the cardiotropic effects of restraint and heart distresses.

At a stimulation rate of 1 Hz, activation of alpha-adrenoreceptors prolonged the AP duration at 10%, 50%, and 90% repolarisation at 10(-7), 10(-6) M in the rat isolated right atria, but shortened it at a higher concentration of 10(-5) M. The frequency-induced depression of the AP duration became more evident in cardiomyocytes stimulated by 10(-7), 10(-6) M and less obvious at 10(-5) M of alpha-adrenoagonist. Activation of alpha-adrenoreceptors by isoprenalin shortened the AP duration and enhanced the stimulation-rate-dependent changes in the atrial AP configuration.

It is shown on isolated aorta preparations that prolonged gamma-irradiation of rats results in depression of endothelium-dependent and endothelium-independent vasodilatation responses to beta-adrenoceptors stimulation by isoprenaline and M-cholinoceptors by carbachol.

It was established that prolonged gamma-irradiation of rats leads to the decrease of amplitude and duration of action potentials of right atrial cells, attenuation of the dependence of these electrophysiological characteristics upon the stimulation frequency, depression of the interval of cardiomyocytes reaction on the hypoxia. The revealed post-radiation changes determine the reduction of function resistance of heart cells bioelectrical activity and promote the initiation of arrhythmias.

It is shown on isolated aorta preparations, that external gamma-irradiation of rats in dose 6 Gy results in intensification of endothelium-dependent relaxation which reaches of maximum in 30th days of post-radiation period. Constriction effect of norepinephrine on preparations without endothelium in remote terms after irradiation decreases with maximum on 90th days.

It was shown with endothelium-containing and endothelium-denuded aorta segments that external gamma-irradiation of rats (6.0 Gy) results in intensification of vasodilatation reactions on beta-adrenoceptor stimulation by isoprenaline with maximum in 30th day of post-radiation period. This post-radiation alteration is not related with endothelium-derived relaxing factor.

Incorporated 137Cs (absorbed dose of 0.26 Gy) causes decrease of myocardial's contractile function and inotropic response to beta-adrenagonists effect, isoproterenol-stimulated adenylate cyclase activity and beta-adrenoreceptors affinity. Adrenergic effects, mediated by alpha-adrenergic structures on heart contractile function, on the contrary, become stronger, that is due to the increase of the receptors' density on sarcolemma surface.

Chronic gamma-irradiation (1 Gy, 100 mR/hr) increases cell titre in rat thymus and decreases glucose transport activation by phorbol ester. Animals kept in the Chernobyl evacuation zone over a period of 30 days exhibit reduced thymus cellularity and decreased PMA (200 nM) stimulation of glucose uptake by thymus cells.

Rats kept within the ten-kilometer zone of Chernobyl disaster over a period of 30 days exhibited a decreased heart function response to beta-adrenoreceptor stimulus, reduced density of the receptor structures in cardiomyocytes and their affinity to specific agonists. The number of beta-adrenoreceptors in myocardium cells was restored in 6 months, but their affinity and heart function response to the effect of beta-adrenoagonists remained decreased. No significant changes were observed in regulation influenced indirectly via alpha-adrenoreceptors.

The influence of incorporated cesium 137 (the absorbed doses of 0.26-0.08 Gy) on the erythrocyte membrane structure has been investigated. It has been shown that chronic internal exposure to gamma radiation causes structural reorganization of erythrocyte membranes at remote postirradiation times (in 3 and 6 months) that influences the annular membrane lipid.

The study was made of the rat heart isolated according to Langendorf and right auricles. Intraperitoneal injections of 2.5 MBq/kg 131I were performed. Electrophysiological and biomechanical myocardium response to stimulation of alpha and beta-adrenoreceptors with isoprenalin and phenylephrine hydrochloride was analyzed. Postradiation modification of adrenergic control in animals with incorporated 131I appeared as reduced functional response of cardiomyocytes and intact heart to beta-adrenoagonist and enhanced response to alpha-agonist was detected.

It was shown on isolated myocardium preparations that internal gamma irradiation of rats with 137Cs (1.6 MBq/kg) decreased the contractile function of ventricles and had no essential effect on the auricle contractility. The inotropic response of myocardium to activation of alpha-adrenergic receptors decreased, and of beta-adrenergic receptors decreased.

It has been shown of isolated muscle preparations of rat heart that external gamma-irradiation with a dose of 6 Gy reduces the contractile capacity of myocardium and changes the chronoinotropic relationships: in the auricle, the rate/power relationship and the potentiating effect of the passive interval increase, and in the ventricles, the potentiating effect decreases. Modification of the chronoinotropic relationships may be associated with changes in the calcium ion transport in the heart cells.

Studies on isolated rat hearts showed that in contrast to 8-month-old animals, in 26-month-old rats the contractile activity of the myocardium increases by the 3rd day after administration of toxic adrenalin doses (1 mg/kg i.m.). The maximum functional response of catecholamine injured hearts to stimulation of alpha- and beta-adrenoceptors reduced in both age groups, while the sensitivity of the myocardium to beta-adrenoceptor agonists in mature rats increased.

The contractile function of myocardium was impaired and its inotropic response to stimulation of alpha- and beta-adrenoreceptors decreased at early times (1-30 days) following whole-body gamma-irradiation with a dose of 1.0 Gy. Six months after irradiation the response of the isolated myocardium to stimulation of adrenoreceptors increased to exceed that of intact animals. In a year the reactivity of the myocardium towards alpha-adrenoreceptor agonists remained high and its sensitivity of phenylephrine hydrochloride increased considerably; the response to beta-adrenoreceptor agonists was virtually absent.

Using the fluorescent probe and membrane filtration methods it has been shown that 3 days after gamma-irradiation of rats with a dose of 1 Gy microviscosity of membranes increases and their Ca2(+)-transport function decreases with a simultaneous increase in the affinity of Ca2(+)-pump for calcium. In 15 days, the characteristics under study do not differ from those of the intact controls.

Experiments were performed on isolated hearts of adult (8-10 months old) and aged (24-26 months old) rats perfused with the Krebs-Henseleit solution according to the method of Langendorf. It was demonstrated that when oxygen supply was insufficient (pO2 of the perfusion solution-100 mm Hg), the chronotropic reaction of the heart to the stimulation of alpha- and beta-adrenergic receptors with phenylephrine hydrochloride (5 x 10(-7)--10(-5) M) and isoprenaline (10(-9)--10(-6) M), respectively, increased in adult rats and decreased in aged animals. Positive inotropic effects of adrenoagonists in hypoxic hearts diminished but their values as well as those at adequate oxygenation (pO2 = 600 mm Hg) were higher in aged rats. Stimulation of adrenoreceptors in the case of inadequate oxygenation increased hypoxic myocardial contracture, the increase being greater in adult rats.

The studies on the isolated papillary muscles have shown age-dependent differences in the tension developed, the rate of its development and decline in adult (10 months) and old (27 months) rats at 0.1 Hz stimulation frequency and different concentrations of external calcium (0.3, 1.25, 5.0). With 0.3 mM of Ca2+ in the solution, the negative inotropic frequency effect, and resting potentiation of contractions (interstimulus interval 30 s) in the myocardium of old rats were considerably lower than those in adult animals. Calcium level elevation (5.0 mM) resulted in elimination of frequency inotropic effect and resting potentiation in the rat myocardium in both age groups. The abnormalities of chronoinotropic relations in the myocardium during aging can probably be explained by the changes in Ca2+ transport.

Hypoxia is shown to decrease chronotropic and inotropic responses of the isolated heart of mature rats to stimulation of M-choline receptors. In aged tissue hypoxia has no influence on the inotropic response to carbocholine effect. The results permit a conclusion to be made on the higher resistance of cholinergic mechanisms that regulate the cardiac function to hypoxic effects in aged animals.

The experiments on rat papillary muscles revealed that in ageing rats myocardium has a decreased distension ability. The curves of shortening value/length and force/velocity for the myocardium of old animals are shifted downwards. The alterations in isotonic contraction parameters had a distinct age differentiation, while the age did not affect the inotropic effects of increased frequency, paired stimulation and external calcium. It is suggested that changes in biomechanical properties of ageing myocardium are associated with alterations in calcium transport in sarcoplasmic reticulum.