[Interaction of C60 fullerene-polyvinylpyrrolidone complex and brain Aß(1-42)-peptide in vitro].

Using a spectrophotometric method changes occurring in solution containing brain Aß(1-42)-peptide, fullerene C60, and polyvinylpyrrolidone were analyzed. Using the Bent-French method relative binding constants of fullerene C60 with Aß(1-42)-peptide and polyvinylpyrrolidone with Aß(1-42)- peptide were determined. These data suggest that Aß(1-42)-peptide interacting with the C60 fullerene-polyvinylpyrrolidone complex partially displaces polyvinylpyrrolidone and generates a new three molecular compound.

[Partitioning of taxifolin-iron ions complexes in octanol-water system].

The composition of taxifolin-iron ions complexes in an octanol-water biphasic system was studied using the method of absorption spectrophotometry. It was found that at pH 5.0 in an aqueous biphasic system the complex of [Tf2 x Fe x (OH)k(H2O)8-k] is present, but at pH 7.0 and 9.0 the complexes of [Tf2 x Fe x (OH)k(H2O)2-k] and [Tf x Fe x OH)k(H2O)4-k] are predominantly observed. The formation of a stable [Tf3 x Fe] complex occurred in octanol phase. The charged iron ion of this complex is surrounded by taxifolin molecules, which shield the iron ion from lipophilic solvent. During transition from water to octanol phase the changes of the composition of complexes are accompanied by reciprocal changes in portion of taxifolin and iron ions in these phases. It was shown that the portion of taxifolin in aqueous solution in the presence of iron ions is increased at high pH values, and the portion of iron ions is minimal at pH 7.0. In addition, the parameters of solubility limits of taxifolin-iron ions complexes in an aqueous solution were determined. The data obtained gain a better understanding of the role of complexation of polyphenol with metal of variable valency in passive transport of flavonoids and metal ions across lipid membranes.

[Effect of Zajdela ascite hepatoma growth on the extracellular antioxidant system of tumor bearer].

The influence of tumor development on the blood plasma antioxidant system in the area of tumor growth has been studied. Zajdela ascite hepatoma transplanted to the abdominal cavity of Vistar rats was used as a model of tumor growth. It hase been found that tumor development produced and imbalance between pro- and antioxidant systems in the organism of tumor bearer. Besides, a sharp decrease in tocopherol and uric acid concentrations (twice), as well as in the concentration of protein SH-groups (seven times) was noted. In the tumor growth area, along with the tocopherol level decrease, a 5-7 fold increase in the concentrations of uric acid and protein SH-groups was observed. As the concentration of low-molecular antioxidants decreases, the major part is played by protein components which bind or oxidize ions of variable valence. Thus, the level of transferrin (Tf, which is responsible for the transport of iron ions, is reduced in 2.5 to 3 times (from 5.0 to 1.6 mg/ml) in the blood plasma, whereas the Tf level in the ascitic fluid increased from 1.5 to 2.7 mg/ml. The concentration dynamics of the other protein functioning together with Tf, ceruloplasmin (Cp), had opposite (inverse) tendencies. Thus, the Cp concentration in the blood plasma increased 1.5-2 times (from 0.55 to 1.1 mg/ml) whereas it decreased from 0.55 mg/ml to 0.35 mg/ml in the ascites.

[Effect of the liposomal form of taxifolin complexes with metals of variable valence on skin regeneration after chemical burn].

The effect of the liposomal form formed by taxifolin and metals of variable valency was investigated. It was shown that the application of preparations based on the free flavonoid and its complexes with Fe(II/III) and Cu(II) ions after chemical burns results in a more effective skin regeneration and the repair of hair follicles and sebaceous glands. A tendency for a more effective wound healing after the applications of taxifolin-Cu(II) and taxifolin-Fe(III) liposomal complexes versus control was observed. It was assumed that the mechanism of action of these preparations is based on the oxidative polymerization and conjugation of the flavonoid, which results in the utilization of toxic metabolites and lipid peroxidation products.

[Influence of Biginelli pyrimidine on production reactive oxygen species by polymorphonuclear leukocytes].

The effect of 6 synthetic Biginelli pyrimidines on production of reactive oxygen species by polymorphonuclear neutrophils was investigated. It has been shown by method of luminol-dependent chemiluminescence that test compounds in a concentrations of 10-100 microM stimulate production of reactive oxygen species. An increase in the reactive oxygen species production by stimulated neutrophils in the presence of 10 microM 1-(3, 4-dimetoxyphenyl)ethyl-4(alkyl/aryl) substituted Biginelli pyrimidines was 50-90 %. An increase in the priming effect of Biginelli pyrimidines on reactive oxygen species production by neutrophils was noted in the case of replacement of phuryl radical by phenyl and alkyl radicals at C(4) pyrimidine cycle and in the case of replacement benzyl radical at N(1) by 3, 4-dimetoxyphenyl radical. It has been revealed a high inhibitory effect of 1-(3, 4-dimetoxyphenylethyl)-4(alkyl/aryl) substituted Biginelli pyrimidine in concentration 0.01-0.10 microM. It has been found that high concentration of ethyl-1-[2-(3, 4-dimethoxyphenyl)ethyl]-6- methyl-4-phenyl-2-thioxo-1, 2, 3, 4-tetrahydropyrimidine -5-carboxylate (1 mM and more) is able to cause respiratory burst of neutrophils without additional stimulation.

[Variations in cell population size and reactive oxygen species level in the blood and the ascites liquid of tumor carrier].

Using Seidel ascites hepatoma as a model, we studied in detail changes in cell population size and in the level of reactive oxygen species in the tumor growth zone and in the blood plasma of tumor carrier. It was found that reduction-oxidation conditions in the blood plasma and in the tumor growth zone were different. Thus, because of hyperactivity and increase in the number of leukocytes, the blood plasma exhibited strong oxidative stress inducing damage to healthy cells, whereas the tumor growth zone showed the decrease in macrophage concentration, as well as in oxygen and ROS levels. These conditions favor intensive growth of tumor cells.

[Peroxidation of lecithin in the presence of dihydroquercetin and its complex with ferrous iron ions].

The ability of the flavonoid dihydroquercetin to prevent or accelerate the accumulation of reactive oxygen species and the metabolites of oxidative stress, carbonyl compounds has been studied. It has been shown on a model of oxidation of lecithin that dihydroquercetin exhibits a prooxidant effect in the alkaline region of pH, whereas at neutral and acidic pH values dihydroquercetin is an effective antioxidant. In the presence of ferrous iron ions, which catalyze the Fenton's reaction, dihydroquercetin forms a complex with metal that shows the antioxidant activity in the region of high pH values. It has been found that the oxidation of lecithin in the presence of 20-200 microM ferrous iron is inhibited by dihydroquercetin to a concentration of 3.2 mM. At higher concentration of dihydroquercetin in the presence of ferrous iron, the accumulation of malonic dialdehyde occurs, indicating the presence of the prooxidant activity of dihydroquercetin.

[A comparison of antioxidant properties of hypoxen and duroquinone by the method of chemiluminescence].

The antioxidant activity of duroquinone and hypoxen was compared with that of alpha-tocopherol and vitamin C in a model system (luminol-peroxidase-H2O2), and their influence on the level of reactive oxygen species in systems containing polymorphonuclear leukocytes of healthy and tumor-bearing animals was studied. It was shown that, in a model chemical system, the concentrations of antioxidants (the inverse of antioxidant activity) necessary to decrease twice the intensity of the chemiluminescence answer (C50%) are arranged in the following order: alpha-tocopherol > duroquinone > hypoxen > ascorbic acid. In this case, the concentrations of the hydrophobic antioxidants (C50% for alpha-tocopherol and duroquinone 10-30 mkM) should be 20-50 times higher than for hydrophilic antioxidants (C50% for vitamin C and hypoxen 0.5-0.6 mkM). It was revealed that the generation of reactive oxygen species by blood phagocytes of tumor-bearing animals is 2-2.5 times higher than by phagocytes of healthy animals. The antioxidant concentration necessary to decrease the chemiluminescence answer in the cellular system should be one order of magnitude higher than in the model chemical system. The distribution of a hydrophobic antioxidant between water/lipid phases promotes an increase in the concentration of the antioxidant necessary to decrease the level of reactive oxygen species twice. Thus, the major factor influencing the antioxidant activity is the constant of distribution of these compounds in a water/lipid system.

[Changes of the goldfish Mauthner neuron ultrastructure and function under the influence of 3,4-dihydro-2(1H)-pyrimidinethione].

The effects of pyrimidine derivative 3,4-dihydro-2(1H)-pyrimidinethione, (DPT) used as a test-system for detection of tumor growth, on the goldfish Mauthner neurons (MN) ultrastructure and function, as manifested in behavioral changes, were studied. The results of investigations demonstrated that an application of DPT on MN had the effects similar to those of dopamine application, as established earlier, causing the enhancement of MN resistance to fatigue stimulation, accompanied by an increase of the dimensions of the actin containing desmosome-like afferent admembranous synaptic contacts, and formation of the cytoplasmic bundles of actin stress-fibers. Similarity of morpho-functional changes of MN, induced by DPT, an artificial chemical substance, which has no receptors on the neuronal membrane, and by natural neurotransmitter dopamine, allows us to suggest possible trophic stabilizing and polymerizing effects of both substances on cytoskeletal actin due to their direct penetration into postsynaptic neuron.

[Cytotoxicity of amyloid fibrils of X-protein].

It is known that amyloid oligomers, protofibrils, and fibrils induce cell death, and antibiotic tetracycline inhibits the fibrillization of beta amyloid peptides and other amyloidogenic proteins and disassembles their pre-formed fibrils. Earlier we have demonstrated that sarcomeric cytoskeletal proteins of the titin family (X-, C-, and H-proteins) are capable to form in vitro amyloid fibrils, and tetracycline effectively destroys these fibrils. Here we show that the viability of polymorphonuclear leukocytes in the presence of X-protein amyloids depends on the concentration of amyloid fibrils of X-protein and the time of incubation. In addition to the disaggregation of X-protein fibrils, tetracycline eliminated the cytotoxic effect of the protein. The antibiotic itself did not show a toxic effect, and the cell viability in its presence even increased. Our results evidence the potential of this approach for evaluating the effectiveness of drugs preventing or treating amyloidoses.

[DNA, proteins and lipids distribution in the cells of olfactory bulbs of rats of various ages].

Using luminescent and absorption stains, specific for DNA (acridine orange, ethidium bromide), proteins (silver nitrate) and lipids (sudan III), the distribution of these substances was studied in the sections of rat olfactory bulbs, fixed by paraformaldehyde. DNA prevalence was found in glomerular cell layer as compared with the mitral one. Large amount of DNA was detected in granular cell layer, underlying the mitral one. The peculiarities of cellular layers of olfactory bulbs of 2-day-old rats were compared with those ones in 1-month-old animals. In rats of different ages, the differences were found in DNA content and distribution between layers, while no differences were detected in total protein and lipids. In 2-day-old rats glomerular underdevelopment was demonstrated.

[Cytotoxic action of polymorphonuclear leukocytes on tumor and normal cells during ascite tumor development in vitro and in vivo].

A vast number of studies, including the authors' own research, support the important role polymorphonuclear leukocytes (PMNL) in the development of ascite tumors. The method of luminol-dependent chemiluminescence (CL) was used to show the presence of two functionally different PMNL pools in a tumor-bearing organism: 1) "primed" PMNL, which circulate in the blood stream, and 2) "activated" PMNL, which are accumulated in the tumor zone and are capable of spontaneous CL. The purpose of the present investigation was to compare cytotoxic effects of primed and activated PMNL on tumor cells (ascite Ehrlich carcinoma (AEC), ascite Zajdel hepatoma) upon co-cultivation, as well as on normal cells of the organism, erythrocytes in vitro and in vivo. Upon stimulation with phorbol myristate acetate (PMA), PMNL effectively damaged AEC cells within the first 24 h until PMNL apoptosis occurred. Upon further co-cultivation, the tumor cells grew in number, which suggest the participation of PMNL in tumor protection. When stimulated with PMNL, pools suppressed tumor growth in vitro, since in this case the cytotoxicity was due to both reactive oxygen species and proteolytic enzymes. As it has been shown earlier by the authors, the functional potential of PMNL increases many times during tumor growth, and we suggested that not only tumor but also normal cells could be damaged. In this connection, we have studied the cytotoxic effect of primed and activated PMNL on rat erythrocytes in vitro on their co-cultivation. On stimulation with PMA, the rate of lysis of erythrocytes by primed PMNL increase many times compared to the norm. The fMLP-stimulated cytotoxity was 1.5-2.0 times higher than in the norm. Activated PMNL without stimulation are capable of producing only a partial lysis of erythrocytes (5-7 %). In order to assess the cytotoxic action of PMNL on erythrocytes in vivo, the hemoglobin content in erythrocytes and blood plasm of rats was measured in the course of tumor growth. The hemoglobin content in erythocytes during growth tumor decreased from 135 +/- 10 to 85 +/- 5 g/l, whereas in the blood plasm the hemoglobin content gradually increased by almost two times. The results enable us to suggest that one of death causes of tumor-bearing organisms may be the cytotoxic action of PMNL on normal cells of the organism caused by hyperproduction of ROS.