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Biomedical subjects

N K Zenkov

Publications and source records attributed to N K Zenkov.

16 recordsLinked to original sources
PubMed2006

Active defense under oxidative stress. The antioxidant responsive element.

This review considers the mechanisms and factors that stimulate transcription of genes regulated by the antioxidant responsive element (ARE). The latter is important for cell defense under conditions of oxidative stress and also for detoxification of electrophilic xenobiotics. There are differences in regulation of intracellular homeostasis involving Nrf2-mediated activation of ARE and other redox-sensitive factors (NF-kappaB and AP-1).

Animals↗
PubMed2002

Generation of reactive oxygen species by mitochondria in senescence-accelerated OXYS rats.

Chemiluminescence assay showed that oxygen reduction and production of superoxide anion and hydrogen peroxide by liver mitochondria in OXYS rats highly sensitive to oxidative stress were less intensive than in Wistar rats. Experiments with cytochrome c oxidase inhibitors showed that decreased O2-. generation in mitochondria of OXYS rats is probably associated with changes in complex III of the electron transport chain.

Aging↗
PubMed2000

Nitric oxide and NO-synthases in mammals in different functional states.

This review deals with the physical and chemical properties of nitric oxide as well as with the mechanisms and enzymes synthesizing this compound in animals including humans. The cytotoxic, vasodilatory, neuromediatory, and other properties of NO are analyzed. Polyfunctionality of NO in the norm and in pathologies of different genesis is shown. It is suggested that the analysis of the mechanisms of cyclic conversion of nitric oxide and the elucidation of the role of all NO metabolism products in living organisms would allow us to approach a more profound understanding of the NO problem in biology and medicine. It is reasonable to think the knowledge obtained in the course of the studies will permit an elaboration of the strategy and tactics of medical treatment of many diseases occurring on the background of disturbance in the mechanisms of formation and utilization of this compound.

Animals↗
PubMed2000

[Normal NO synthases and in pathology of different origins].

The paper deals with the physicochemical properties of nitric oxide (NO) and with the mechanisms of its action and synthesis in man and animals. The cytotoxic, vasodilatory, neuromediator, and other properties of NO are analyzed. NO is shown to perform many functions in health and in diseases of various genesis. Analyzing the structure and functions of NO in health and in diseases suggests that they all have both structural and functional properties and their own features. The currently available data lead to the conclusion that the NO-synthase mechanism that is responsible for the production of NO is its synthesis in the presence of oxygen. During functional exercises and hypoxia of various origin, another mechanism of NO may become active, which is associated with the reduction of NO2- in NO.

Animals↗
PubMed1995

Ketoconazole inhibits oxidative modification of low density lipoprotein.

Known cytochrome P450-dependent oxygenase inhibitor ketoconazole (5-50 microM) blocked the murine macrophage-mediated modification of human low density lipoprotein (LDL) as measured by production of thiobarbituric acid-reactive substance, stimulation of [125I]LDL degradation in a fresh set of macrophages and LDL electrophoretic mobility, in a dose-dependent manner with complete inhibition at 30-40 microM. When resident macrophages were incubated with LDL in the presence of metyrapone, methoxsalen and alpha-naphthaflavone at concentrations that have been shown to inhibit the cytochrome P450-dependent oxygenases, there was no change in LDL modification. Induction of benzo[alpha]pyrene hydroxylase activity in macrophages by 24 h incubation with benzo[alpha]pyrene was accompanied by a 1.5-fold increase of LDL modification which has been leveled down by ketoconazole as well as methoxsalen and alpha-naphthaflavone. Furthermore, ketoconazole effectively diminished cell-free LDL oxidation induced by iron, but not copper ions, and reduced the spontaneous and zymosan-stimulated lucigenin-amplified chemiluminescence of macrophages. The data allow us to suggest that ketoconazole inhibits LDL oxidation by acting as an iron chelator and/or inhibitor of prooxidant forms of iron-containing enzymes.

Animals↗
PubMed1991

[H2O2-induced blood serum biochemiluminescence].

Significant differences in the intensities of H2O2-induced biochemiluminescence of venous and capillary blood sera were revealed, as was a direct relationship between this parameter and hemoglobin level in the samples; this permits a conclusion on the improper employment of H2O2-induced biochemiluminescence of blood serum in diagnostic studies.

Blood↗
PubMed1991

[Granulocyte metabolic activity in chronic nonspecific lung diseases].

Biochemiluminescent (BCL) investigation of oxidative metabolism in patients suffering from chronic nonspecific lung diseases (CNLD) has shown activation of granulocyte metabolism measured by zymosan-dependent luminol-amplified chemiluminescence and the intensification of lipid peroxidation estimated by spontaneous serum BCL. At the same time H2O2-induced BCL was decreased, attesting to the abatement of antioxidative activity. The revealed imbalance of oxidative and antioxidative processes may be the pathogenic factor in CNLD development.

Adolescent↗
PubMed1990

[A comparative analysis of the chemiluminescence of capillary and venous blood granulocytes].

The parameters of zymosan-stimulated luminol-dependent chemiluminescence of whole capillary and venous blood were compared in patients with chronic nonspecific diseases of the lungs. The parameters of a chemiluminescence response were in good correlation in general, but the mean values of luminescence intensity of granulocytes from the blood collected from the finger were 1.6 times lower that may be explained by the inhibiting effects of the lymph and intercellular fluid.

Adult↗
PubMed1982

[Biochemiluminescence of the human body surface].

Biochemiluminescence of human body surface was studied with a modern photometric apparatus. It was shown that different parts of the body surface had different radiation levels. Open parts of human body (face, palms) and feet had the highest radiation level. The maximum radiation was detected in the blue spectrum range. The intensity of such biochemiluminescence was about 10 photons/sec/cm2.

Adolescent↗
PubMedDate not supplied

[Blood granulocyte priming in inflammation].

Metabolic activity of peripheral blood granulocytes during the development of inflammatory processes in animals (rats) was studied by chemiluminescence (CL) with luminol. Intensification of the CL- response of granulocytes during an acute inflammatory process induced by intravenous or intraperitoneal zymosan injection reflected the development of mononuclear infiltrative processes. No changes occurred in CL of circulating granulocytes in oxidative injury to the lungs of rats breathing pure oxygen, which was attended by increased infiltration of polynuclear cells.

Animals↗
PubMedDate not supplied

[The effect of UV-radiation on the metabolic activity of human blood granulocytes].

Influence of UV irradiation (254 nm) on chemoluminescence of blood granulocytes was studied in patients with chronic unspecific lung impairments. Chemoluminescence of leukocytes was decreased after blood irradiation at the rate 10 J/ml as well as after the first course of the UV irradiated blood transfusion. At the same time, high dissimilarity of reactions to the irradiation was found in individual patients: in patients with low initial parameters of metabolism a stable decrease of chemoluminescence was observed to the 2nd, 3d and 4th courses of the irradiation, while in patients with high parameters--only to the 2nd course. This suggests that functional activity of phagocytes may be altered due to UV irradiation effects.

Blood Transfusion, Autologous↗
PubMedDate not supplied

[Change in the oxidative metabolism of macrophages during transformation into foam cells].

Oxidative metabolism of murine peritoneal macrophages was studied after cultivation in a mixture containing acetylated low density lipoproteins within 24 and 48 hr using luminol- and lucigenin-dependent chemiluminescence. Chemiluminescence of foamy cells, induced by opsonized zymosan, was not distinctly altered as compared with native macrophages; at the same time, the rate of both lucigenin- and luminol-dependent spontaneous chemiluminescence was distinctly decreased. The imbalance of the oxidative reactions observed enables the authors to propose the antioxidative mechanism of atherosclerotic lesion.

Acetylation↗
PubMedDate not supplied

[Effect of cytochrome P-450 inhibitors on oxidative modification of low-density lipoproproteins by macrophages].

Unlike other cytochrome P450-dependent oxygenase inhibitors, ketoconazole has been shown to suppress the murine macrophage-mediated oxidative modification of human low-density lipoproteins (LDL) in a dose-dependent manner. The benzo[alpha]pyrene-induced microsomal monooxygenase activity was accomplished by a 1,5-fold increase in LDL oxidation by macrophages, ketokonazole (20 mu), methoxalene (20 mu), and alpha-naphthaflavone (50 mu). Ketoconazole was also effective in inhibiting macrophageal NADPH oxidase and LDL autooxidation induced by Fe2+ rather than Cu+, which is likely to be associated with its ability to act as a chelator of free and heme-bound iron ions.

Animals↗