Showing papers in "Ukraïns'kyĭ biokhimichnyĭ zhurnal in 2003"

Molecular mechanisms of apoptosis.

Abstract: Apoptosis (Programmed Cell Death) is a genetically regulated, morphologically distinct form of cell death that can be initiated by many different physiological and pathological stimuli. Such strategic intracellular programming is initiated in many instances during normal life cycle and development in order to maintain the homeostasis of a multicellular organism, to eliminate unwanted cells. However, apoptosis is also involved in a wide range of pathologic conditions, including neurodegenerative and cardiovascular diseases, cancer and autoimmune diseases. Therefore, the ability to understand and manipulate the cell death machinery is an obvious goal of medical research. Here we review the basic components of the death machinery, discuss their interaction in regulation of apoptosis, and describe the main pathways that are used to activate apoptosis.

Phospholipid and cholesterol levels in the tumor cell plasma membranes with different sensitivity to doxorubicin

Abstract: The investigation is aimed to study qualitative and quantitative composition of phospholipids, cholesterol content and lipids unsaturation index in plasma membranes of Guerin's carcinoma cells sensitive or resistant to doxorubicin. The comparison of infrared spectra and phospholipids unsaturation index showed that the unsaturation level of fatty acids in plasma membrane from resistant cells was lower than that from sensitive carcinoma cells. 31P-NMR spectroscopy of plasma membranes phospholipids shows the increase of phosphatidylserine and sphingomyeline content in plasma membrane isolated from resistant tumor as compared with sensitive tumor. The levels of phosphatidylcholine and phosphatidylethanolamine were equal in drug-resistant and drug-sensitive carcinoma strains. Changes in plasma membrane from resistant cells result in elevation of plasma membrane microviscosity and phosphatidylserine level increase can suggest the activation of P-glycoprotein-mediated efflux of doxorubicin.

Effect of temperature on structure and functional properties of horseradish peroxidase

Abstract: The dynamics of structural and functional changes proceeding in a peroxidase molecule under the effect of temperature was studied. It was shown that peroxidase thermoinactivation proceeds in two consequent stages. Based on the analysis of enzyme peroxidase and oxidase activity and peroxidase spectral and buffer characteristics, it was established that at temperatures from 20 to 55 degrees C reversible conformation there occur changes of the hemoprotein molecule related to consequent unfolding and folding of the protein globule. The influence of temperature of 60 degrees C and above induces the protein globule unfolding and loosing of peroxidase activity.

Enzymes of snake venoms

Abstract: Snakes' venom is a mixture of biologically active substances, containing proteins and peptides. A number of these proteins interact with haemostasis system components. Activators and inhibitors affecting blood coagulation and fibrinolysis systems are of special interest. Venom components can be classified into three main groups, such as procoagulants, anticoagulants and fibrinolytic enzymes according to their action. This review is focused on enzymes from Agkistrodon halys halys venom. They are thrombine-like enzyme, named Ancystron-H, flbrinogenolytic enzyme, protein C activator and platelet aggregation inhibitor. Ancystron-H is used for determination of fibrinogen level in blood plasma of patients undergoing heparin treatment and blood coagulation inhibitors accumulation. The fibrinogenolytic enzyme can be used as the instrument for protein-protein interactions in fibrinogen-fibrin system. The protein C activator is used for protein C level determination in blood plasma with different pathologies. Functions of the platelet aggregation inhibitor, belonging to disintegrins group, can be used for development of antithrombotic preparations. Information about the use of snake venoms in science and medicine is presented.

[Use of 1- and 2-thionaphthylacetates as cholinesterase substrates].

Abstract: 1- and 2-thionaphthylacetates were tested as cholinesterase substrates. It was shown that the butyrilcholinesterase from horse serum can hydrolize these compounds. The hydrolysis velocity of 1-thionaphthylacetate was comparable with hydrolysis velocity of acetylthiocholine (the well known cholinesterase substrate), but 2-thionaphthylacetate was hydrolysed more slowly. The values of the kinetic parameters V and K(m) for butyrylcholinesterase hydrolysis of 1- and 2-thionaphthylacetates were determined. It was offered to use 1-thionaphthylacetates as the substrate for cholinesterases.

[Metallothioneins: the structure and mechanisms of action].

Abstract: Metallothioneins (MT)--4 groups (MT-I, II, III and IV) of low molecular mass (approximately 6.5 kDa, 61-62 amino acid residues) cytosol proteins. They are rich in sulphur--20 residues for cysteine, are found in cytosol and nuclei of eucaryotic cells. MT-I and MT-II are found in all animal tissues, MT-III and MT-IV--in the brain. The functions of MT are regulation and control of redox-homeostasis, thioldisulphide equilibrium in the cell in synergism with GSH. MT molecule involve two domains, alpha and beta. MT gene promoter have response elements to metals (MRE), to glucocorticoids (GRE) and to oxidative agents, electrophilic compounds and xenobiotics (ARE). Expression and synthesis of MT are induced for heavy metals (Zn, Cu, Cd and so Hg, Pb, As, Ni, Ag a.o.); glucocorticoids and other stress-hormones and cytokines; free radicals, peroxides, cancerogens and antitumor drugs, UV and ionizing radiation. Zn and partially Cu are physiological inductors of MT. Other inductors act more or less actively as stress-agents. Zinc stabilizes MT molecule, enhances some of their functional activities as a scavenger of metal ions, of free radicals, toxins and xenobiotics. MT are exceptional protection agents for embryo and adult from Cd and other heavy metals, from ionizing radiation, cancerogens, alkylating and DNA-linked agents, from oxidative stress. MT realizes negative control of immune system functions, of transcription factor NF-kB activity. The use of genetic engineering achievements (transgenic mice with defective MTF-1-genes and MT-overexpressing genes) enlarge the possibilities of MT study and application.

[Effect of mycotoxin T-2 on bioluminescence intensity of bacteria].

Abstract: The acute and chronic toxicity of T-2 was studied by bioluminescent method with the use of two strains of luminous bacteria--P. phosphorum Sq3 u V. fischeri F1 as biological objects. It was shown that in acute experiments after 10 min incubation of bacteria in the presence of T-2 the bioluminescence inhibition on the 50% level was observed at the toxin concentration equal to 12 mg/mL. In chronic experiments such a level of bioluminescence inhibition was registered after 16 hours incubation at the toxin concentration of 18 mg/mL. T-2 toxicity was also investigated in the presence of different serum albumin concentrations. It decreases with the increase of albumin concentration at the short term of incubation (5 min) of the mixture to be analyzed. In case of the longer term of incubation (up to 30 min) of this mixture T-2 toxicity was restored. Probably, it is a result of destruction of protein-toxin complex, which is, evidently, reversible and may be characterized by some index. It is necessary to emphasize that the sensitivity of T-2 analysis increases under the decrease of pH value up to lower bacterial physiological level, i.e. to 5-5.5. The revealed abilities of T-2 toxin effect on the intensity of bacterial bioluminescence may be used under the development of instrumental analytical approach on the basis of biosensor technology for testing this toxin in the environment. Taking into account the analysis simplicity and rapidity, such analytical device may have a perspective for wide practical application.

Biosynthesis of poppy isoquinoline alkaloids in nature and in vitro culture. 1. Opium poppy (Papaver somniferum L.)

Abstract: The analysis of literature data on production of isoquinoline alkaloids by Papaver somniferum L. plants and cell cultures has been made. The relationship of morphinane alkaloids biosynthesis with the processes of tissue and cell differentiation are discussed. The information on enzymes and pathways of regulation of morphine and sanguinarine biosynthesis are presented. The data on sanguinarine and morphine physiological role are analyzed.

Changes of mitochondrial oxidation and phosphorylation in the testes of white rats under excessive supply of sodium nitrate into the organism

Abstract: The functional state of mitochondria, obtained from the testicles, after chronic intoxication by sodium nitrate (in a dose of 200 mg/kg during 14; 30 and 90 days) was investigated in experiment on white rats It was revealed, that in dynamics of changes of mitochondrial oxidation and phosphorylation in the testicles under the excessive supply of sodium nitrate into the organism the determined phases should be marked: on the 14th day of intoxication this is the ascending of rate of respiration, on the 30th and 90th day--separation of the mitochondrial oxidation and ADP phosphorylation It is supposed, that in pathogenesis of these changes the essential role belongs to nitric oxide production

The problem of prozone in serum antibody titration and its mathematical interpretation.

Abstract: The question of the mechanism of "prozone" creation was considered from the point of view of the concentrations of free and semi-blocked bivalent antibodies in the mixture of these antibodies with monovalent antigen. Using the so called "coordinates of dilution", suggested by the author earlier, it was possible to calculate the relationships between the concentrations of either free or semi-blocked bivalent antibodies and the dilution of the antigen-antibody mixture. It was shown that dilution of antigen-antibody mixture leads to an increase of the concentration of free bivalent antibodies and simultaneous sharp decrease of the concentration of semi-blocked antibodies. It is suggested, that such a relationship is quite enough for the creation of prozone effect in reactions, when only bivalent antibodies are active and semi-blocked antibodies compete with free antibodies, providing inhibition of the reaction.

[Effect of acetaldehyde on ethanol- and aldehyde-metabolising systems of the liver and brain of rats].

Abstract: Lately the mechanism of craving for alcohol has been related to the local level of brain acetaldehyde occurring in ethanol consumption and depending on the activities of the brain and liver ethanol and acetaldehyde-metabolizing systems. In this connection, we studied the effect of chronic acetaldehyde intoxication on the activities of alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), the microsomal ethanol oxidizing system (MEOS) and liver and brain catalase as well as ethanol and acetaldehyde levels in the blood. The results showed that the chronic acetaldehyde intoxication did not alter significantly the activities of liver ADH, MEOS and catalase as well as liver and brain ALDH. In parallel with this, the systemic acetaldehyde administration led to shortened time of ethanol narcosis and activation of catalase in the cerebellum and left hemisphere, which may indicate involvement of this enzyme into metabolic tolerance development.

Determination of the binding parameters for a pre-existing antigen-antibody mixture.

Abstract: A new method, which allows to evaluate parameters of interaction between antibodies (or receptors) and an antigen (or ligand) is suggested The method is based on the use of so-called coordinates of dilution suggested by the author earlier Representation of the data of the titration curves for the mixtures of antibodies (or receptors) and antigen (or ligand) in these coordinates allows one to determine the affinity of interaction and the concentration of antigen (or ligand), which can reversibly block antibodies (or receptors) Simple formulas, which allow to estimate which part of paratopes or bivalent antibodies is free and which part is blocked by the antigen, depending on dilution of the considered system, are also suggested Such a method could be useful for characterization of infection and autoimmune processes when the antigen and antibodies circulate together in the bloodstream

[Effect of omega-3 polyunsaturated fatty acids on activity of glutathione-dependent enzymes in the liver cytosol and blood erythrocytes in rats with experimental chronic bronchitis and in the norm].

Abstract: The influence of omega-3 polyunsaturated fatty acids (omega-3 PUFA) on the activity of glutathione reductase, glutathione transferase and glutathione peroxidase in the liver cytosole and red blood cells of normal rats and animals with experimental chronic bronchitis. omega-3 PUFA ("Tekom" medication) activate glutathione reductase of liver cytosole and glutathionperoxidase in the red blood cells in rats. In the rats with chronic inflammatory process in bronchia omega-3 PUFA corrects the glutathione-dependent systems of detoxication. Effects were more expressed in the liver cytosole in comparison with the red blood cells. The using of omega-3 PUFA as a means for treatment and prophylaxis was more effective than for treatment only.

[Interferon-induced 2',5'-oligoadenylate system: key components and biological functions].

Abstract: The current data about the 2',5'-oligoadenylate system is reviewed. Its role in interferon signaling and cell metabolism regulation is discussed. The interferon system is known to be characterized by a wide range of biological functions such as antiviral defense, control of cell growth and differentiation, oncogenic stability, apoptosis, immune activation, etc. The biological role of interferon that is the multifunctional cytokine is discussed more in detail. The structure of main components of interferon signal transduction cascade (2',5'-oligoadenylate, 2',5'-oligoadenylate-synthetase and ribonuclease L) is reviewed. The interferon-induced 2',5'-oligoadenylate system is considered as the component of common regulatory system coordinating cell metabolism.

[Effect of nickel compounds on glutathione-dependent antioxidant system of pea and maize shoots].

Abstract: Accumulation of Ni ions in vegetative bodies of 6- and 10-days shoots of peas and maize, as well as the influence of Ni compounds on accumulation of the glutathione reduced form and activity of glutathione-dependent antioxidant enzymes were investigated. It was established, that Ni accumulation by the root system of plants is carried more efficiently, than by leaves. The increase of concentration of these toxic cations in cultivation medium results in the decrease of the glutathione reduced form in vegetative bodies of plants. A general tendency to the increase of antioxidant enzymes activity is shown under the action of Ni compounds.

Antioxidant properties of rhenium cluster complexes with butyric acid derivatives in blood plasma and erythrocytes

Abstract: The antioxidant action of rhenium cluster complexes with isobutiric and gamma-aminobutiric acids were studied in vitro. It was established that strong antiradical properties were found in the reaction with stable radical diphenylpycrylhydrazile Re2(i-C3H7COO)4Cl2, [Re2(GABA)2Cl5(H2O)]Cl.2H2O. The chemiluminescence investigation of antioxidant properties of both substances Re2(i-C3H7COO)4Cl2 and [Re2(GABA)2Cl5(H2O)]Cl.2H2O has established that these properties are realized in the blood plasma and erythrocytes, but to different extent.

[Changes of nitric oxide level at different stages of primary open-angle glaucoma].

Abstract: The contents of NO stable metabolites in tears, and blood serum of the patients with different stages of open-angle glaucoma have been studied. The increasing of NO stable metabolite contents was found in tears, aqueous humor and blood serum during glaucoma progression. The depletion of glaucoma pathogenesis oxidative link was found at the terminal stage of the disease. The results of our investigation are proposed to be used for glaucoma diagnostic.

[Effect of forskolin and quinacrine on leukocyte functions under the effect of low-dose radiation].

Abstract: The adenylate cyclase and phospholipase A2 incorporation in the functional responses as well as lipid peroxidation processes and glutathione system homeostasis of animal leukocytes to small doses of ionizing radiation (1-100 mGy) have been estimated. The cells were irradiated by introduction of radioactive isotope 14C-leucine into the incubation medium. It is established that the ionizing radiation has different effects on the modification of cellular functions by the agents, which change adenylate cyclase and phospholipase A2 activity. Neutralization of stimulative irradiation effect on chemokinesis of polymorphonuclear leukocytes by quinacrine (the inhibitor of phospholipase A2) indicates for certain, that metabolism of eicosanoids takes immediate part in the cell response to ionizing radiation. Apparently, adenylate cyclase has no influence on this process, where at indicates the lack of influence of forskolin (the stimulator of adenylate cyclase) on the spontaneous motility, and on the radiation action on this leukocyte function. Rosette forming ability of lymphocytes is regulated by both enzymes because it is modified both by the inhibitor of phospholipase A2, and by the adenylate cyclase stimulant. In this case it is impossible to exclude the action of ionizing radiation both through the adenylate cyclase cascade, and through the eicosanoid metabolism. In all the concentration range the radionuclides do not affect the studied biochemical indexes of the cell, but change the action of the modifiers.

[Catalytic characteristics of 5'-nucleotidase in the structure of cell membrane rafts in smooth muscles].

Abstract: 5'-nucleotidase (EN 3.1.3.5) is widely distributed enzyme occurring in vertebrate, bacterial and plant cells. The main physiological function of 5'-nucleotidase is hydrolysis of 5'-AMP to adenosine and Pi. It was found that the detergent-insoluble membrane domains (rafts) are enriched by proteins possessing high 5'-AMPase activity. This study is aimed to investigate some physical and chemical properties of 5'-nucleotidase, which is present in detergent insoluble membrane domains isolated from pig stomach and lung. It was shown for the first time that catalytic properties of the raft-associated 5'-nucleotidase and of the pure enzyme described in literature differ. Our results demonstrate that the greatest activity of the raft-associated enzyme takes place in the physiological conditions contrary to the pure enzyme. Our data suggest that such changes of 5'-nucleotidase catalytic activity might be due to the disruption of its interaction with membrane rafts.

Interaction of annexin VI with actin

Abstract: Actin polymerization was investigated using fluorescence probe N-(1-pyrenyl)iodoacetamide, which was bound covalently to reactive sulfhydryl group, Cys-373. Labeled actin in the bulk was 0.5 to 1% of total actin concentration. Actin polymerization at concentration 12 mM was started by addition of 20 mM KCl and 2 mM MgCl2. The label fluorescence was excited at 365 nm and registered at 386 nm. Under actin polymerization the label fluorescence increased almost 10 times. Two main phases may be distinguished in the process of actin polymerization: 1) monomer activation and nucleus (trimer) formation, 2) growth of actin filaments on the nuclei. In our experimental conditions, both for pure actin and for that with added annexin VI, the 1st phase continued for about 3 min and after that the 2nd phase was perfectly approximated by exponential dependence. An analysis of the exponential curves showed that actin monomer lifetime increased from 327 s, at annexin absence, to about 373 s at 0.7 microM annexin and more. Calculation of rate constants at two ends of growing actin filament suggests that annexin VI binds with pointed ("slow") end so that at sufficient annexin concentration the filament grows only on barbed ("fast") end. Our results, together with data of other researchers showing that annexin VI binds with the inner membrane surface of smooth muscle cell through Ca2+, may indicate that, at Ca2+ entering the cell, this annexin binds actin filament pointed ends to cell surface making it ready for the act of contraction.

The influence of high ambient glucose level on the production of pericellular glycosaminoglycans by cultured endothelial cells.

Abstract: The 14C-acetate metabolic labeling of glycosaminoglycans (GAGs) was used to investigate the effect of high glucose level on the production of hyaluronic acid (HA), heparan sulphate (HS), chondroitin sulphate (CS) and dermatan sulphate (DS) by human immortalized umbilical vein endothelial cells. It is demonstrated that 30 mM glucose decreased the accumulation of HS and increased the accumulation of CS and DS in the cell layer, pericellular matrix and conditioned medium in 48 h of incubation. The modulation of the overall metabolism of sulphated GAGs by high glucose is in contrast to the observed redistribution of HA from the conditioned medium to the pericellular matrix of endothelial cells. The preincubation at 30 mM glucose increased also the attachment of hyaluronidase-treated endothelial cells to HA-coated surface and had no effect on the cell attachment to poly-D-lysine, indicating the alterations of CD44 binding to immobilized HA. The treatment of endothelial cells with p-nitrophenyl-beta-D-xylopyranoside, which inhibits the coupling of CS to the core protein, attenuated high glucose-induced pericellular HA accumulation and decreased cell attachment to HA-coated surface. It is supposed the implication of CD44-related CS in the accumulation of pericellular HA by endothelial cells exposed to high glucose level.

[Intracellular localization of thiamine-binding proteins in the liver and kidneys of rats].

Abstract: The distribution of thiamine-binding and thiamine triphosphatase activity typical of thiamine-binding proteins was studied in intracellular structures of rats liver and kidneys. It was found that the fraction of microsomes has the highest rate of specific thiamine-binding activity amide fractions of subcellular structures that was isolated using differential centrifugation in the both organs. Hydrolysis of thiamine triphosphate (pH 7.4) was also extremely active in these structures. The results of our research allow to make a conclusion that subcellular structures precipitated as fraction of microsomes (endoplasmic reticulum and vesicled parts of plasma membranes) are the sites of the most probable localisation of thiamine-binding proteins of liver and kidneys.

[Effect of the composition of branched chain amino acids, taurine, and tryptophan on the amino acid metabolism in experimental models of alcoholism]

Abstract: Ethanol withdrawal after forced alcoholization of rats according to Majchrowicz led to the development of amino acid imbalance in the pool of free amino acids in the liver (increasing levels of alanine, aspartate, glutamate, glutamine and histidine, decreasing levels of glycine, lysine, threonine and taurine) and blood plasma (increasing levels of tyrosine and alanine, decreasing levels of most glycogen aminoacids, branched-chain aminoacids and Lys). Less profound changes were observed after prolonged alcohol intoxication (decreasing levels of alanine, ornitine, citrulline and increasing level of Glu in liver, increasing levels of sulfur-containing compounds, Asp and Lys in blood plasma). Amino acid mixture which contained branched-chain amino acids, taurine and tryptophan administered intragastrically was found to correct levels of sulfur-containing amino acids, threonine, lysine and isoleucine after ethanol withdrawal and to eliminate disorders in urea cycle, exchange of threonine, glycine and phenylalanine after prolonged alcohol intoxication.

[Effect of ADP and GroES on interaction of molecular chaperonin GroEL with non-native lysozyme].

Abstract: The interaction of the molecular chaperonin GroEL with fluorescein-labeled lysozyme in the presence of high concentrations of thiol reagent--dithiothreitol (DTT) has been studied. In case of high concentrations of DTT lysozyme loses the native conformation due to the disruption of the intramolecular disulfide bonds stabilizing its structure and effectively aggregates. It has been shown that in the presence of high concentrations of DTT and two-fold molar excess of GroEL the lysozyme tightly interacts with GroEL that essentially decreases the efficiency of its aggregation. The addition of ADP to the complex of GroEL with nonnative lysozyme noticeably decreases the interaction of the chaperonin with nonnative protein target resulting in some increase of the efficiency of its aggregation. However, the addition of the co-chaperonin GroES together with ADP (i.e. the formation of the complex of GroEL with GroES) leads to drastic weakness of the interaction of GroEL with nonnative lysozyme and the efficiency of its aggregation becomes comparable with that in the absence of GroEL.

[Use of three-hybrid system to detect RNA-binding activity of alfalfa mosaic virus coat protein].

Abstract: We used yeast three-hybrid system, for studying interaction of alfalfa mosaic virus coat protein AMVCP (AMVCP) with RNA4, which codes this protein. We have shown that AMVCP with high affinity is bound to plus-chain of RNA4 in vivo. The mutational analysis has shown, that the N-terminal part of AMVCP (aa 1 to 85) contains RNA-binding domain. C-terminal part of this protein (aa 86 to 221) does not participate in direct interaction with RNA4. However activity of the reporter-gene LacZ, which codes beta-galactosidase, in case of interaction only N-terminal part of AMVCP is five times lower, in comparison with full-length hybrid protein, that confirms that the tertiary structure of full-length AMVCP is more favourable for interaction with RNA4.

Ontogenic characteristics of lipid peroxidation and antioxidant system enzymes in the brain of geese

Abstract: Peculiarities of antioxidant homeostasis of geese brain tissue during embryogenesis and early postnatal period have been studied. It has been shown that the cerebrum and hindbrain tissues are characterized by a higher level of lipid peroxidation compared to liver. Main antioxidative enzymes' activity (superoxide dismutase, catalase, glutathione peroxidase) in the brain already reaches its maximum in the middle period of embryogenesis. We have found that brain tissues are characterized by a lower activity of intracellular enzymes (superoxide dismutase, catalase) but increased glutathione peroxidase activity as compared to liver. The rate of Fe2+ initialized lipid peroxidation and coefficient of antioxidative activity were used as a criterion for evaluation of antioxidative system's status. According to the dynamics of these factors the highest tension of antioxidative system in the brain appears in the period of the contour (28 days) and juvenile (49 days) feather formation.

Homocysteine metabolism and its role in pathology

Abstract: Results of the study of homocysteine metabolism and its role in physiological and pathological processes are given in this review. The participation of homocysteine in the process of methionine synthesis, transsulfuration, formation of homocysteine thiolacton and their regulation, polymorphism of homocysteine metabolism enzymes, the ways of homocysteine and thiolactone incorporation into protein molecule, sources and forms of homocysteine in the blood plasma, the role of hyperhomocysteinemia in pathogenesis of cardiovascular and other diseases have been considered. Principles of homocysteine determination in the blood plasma are described here.

Proteolytic enzymes and apoptosis

Abstract: Information about basic mechanisms of programmed cell death (apoptosis) development with participation of proteolytic enzymes is given in the review. The basic mechanisms of apoptosis launching are conditionally subdivided into three groups, depending on the "points of application" of apoptosis development initiating factor: membrane (receptor-dependent), mitochondrial and nuclear. Attention is accentuated on ubiquitin-dependent proteasomal proteolysis as the key system regulating apoptosis. The possible disturbances of apoptotic program realization are specified under various pathological processes and diseases.

Interferonogenic activity of immobilized ribopolynucleotides in vitro

Abstract: In vitro experiments the authors have studied a property of yeast RNA--tilorone hydrochloride complex covalently linked to spheron to induce the synthesis of interferons type I (alpha- and beta-interferons) in the culture of peripheral mononuclear human cells. Such a complex is shown to possess a marked interferonogenic activity. The data obtained appear to be a proof of the interferon induction to be realised by a mechanism needing at the first stage the contact between the inducer and the cell surface without its penetration into the cell.

Activity of antioxidant enzymes in enterocytes of the small intestine and blood cells after ionizing irradiation and administration of vitamin E in rats

Abstract: The long-term influence of low X-ray irradiation increases lipid peroxidation (LP) in radiosensitive (bone marrow, enterocytes of small intenstine) and in relatively radioresistant blood cells (erythrocytes). The activation of antioxidant system enzymes in observed cells does not decrease LP intensity. We concluded that additional administration of alpha-tocopherol provided the decrease of the first and end products of LP in the observed tissues mostly in the beginning of the experiment. Antioxidant effect of the preparation is more significant in cells with high proliferative activity but normal activity of enzymes was not determined.