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Biomedical subjects

G I Klebanov

Publications and source records attributed to G I Klebanov.

At least 19 recordsLinked to original sources
PubMed2005

Changes in superoxide dismutase activity and peroxynitrite content in rat peritoneal macrophages exposed to He-Ne laser radiation.

The formation of reactive oxygen and nitrogen species by rat peritoneal macrophages induced by a low-intensity He-Ne laser radiation (LR) was studied in this work. It was found that the formation of reactive oxygen species, nitric oxide, and peroxynitrite as well as changes in the activity of superoxide dismutase (SOD) depended to a large extent on the LR dose. In particular, it was found that activation of SOD at low LR doses was accompanied by nitric oxide level increase, while the level of peroxynitrite showed no significant changes. On the other hand, an enhanced LR dose inhibited the enzyme, and this was accompanied by peroxynitrite accumulation. All the measurements were carried out the day after LR treatment. The revealed regularities consequently demonstrate the existence of a deferred LR action on macrophages associated with the production of reactive oxygen and nitrogen species.

Animals↗
PubMed2004

Photobiological principles of therapeutic applications of laser radiation.

Laser therapy based on the stimulating and healing action of light of low-intensity lasers (LIL), along with laser surgery and photodynamic therapy, has been lately widely applied in the irradiation of human tissues in the absence of exogenous photosensitizers. Besides LIL, light-emitting diodes are used in phototherapy (photobiostimulation) whose action, like that of LIL, depends on the radiation wavelength, dose, and distribution of light intensity in time but, according to all available data, does not depend on the coherence of radiation.

Animals↗
PubMed2003

Comparative study of antioxidant properties of immunoregulatory peptides.

We studied antioxidant properties of immunofan, bursin, cyclobursin, thymopoietin II fragment, glycine, and Siberian ginseng. Experiments were performed in 2 model systems: Fe(2+)-induced oxidation of multilamellar phospholipid liposomes in a heterogeneous water-lipid system and oxidation of luminol induced by alpha,alpha'-azo-bis(isobutyramidine dihydrochloride) in a homogenous aqueous system. By the ability to entrap lipid peroxyl radicals, antioxidant activity of substances decreased in the following order: Siberian ginseng extract>bursin>cyclobursin>thymopoietin II fragment>immunofan, glycine. Siberian ginseng extract and thymopoietin II fragment interacted with Fe(2+), which contributed to elimination of catalyst of lipid peroxidation from the system. The ability of substances to interact with aqueous peroxyl radicals and luminol radicals decreased in the following order: Siberian ginseng extract>thymopoietin II fragment>immunofan>glycine, cyclobursin, bursin. Substances with high antioxidant activity improved the state of the endogenous antioxidant system and protected cells from oxidative stress. They entrapped reactive oxygen species formed in the cytoplasm, modulated free radical processes, and regulated the synthesis of bioactive molecules.

Antioxidants↗
PubMed2001

Mechanism of therapeutic effect of low-intensity infrared laser radiation.

The effect of infrared low-intensity laser irradiation on functional activity of blood polymorphonuclear leukocytes was studied in vitro. A dose-dependent priming of polymorphonuclear leukocytes induced by infrared low-intensity laser irradiation was demonstrated. Similar effects were also observed in the presence of the photosensitizer photosense.

In Vitro Techniques↗
PubMed2000

Effect of the combined action of flavonoids, ascorbate and alpha-tocopherol on peroxidation of phospholipid liposomes induced by Fe2+ ions.

The effect of alpha-tocopherol, ascorbate, rutin and dihydroquercetin on chemiluminescence (CL) accompanying the Fe2+-induced peroxidation of unsaturated fatty acids in phospholipid liposomes has been investigated. The amplitude of CL decreased and the latent period increased in the presence of alpha-tocopherol, rutin and dihydroquercetin which is typical of peroxide radical traps. Ascorbate also reduced the CL amplitude but only at small concentrations up to about 4 microM. A further increase of ascorbate concentration had a negligible effect on the amplitude. At the same time, the latent period in CL development increased with the growth of ascorbate concentration, apparently, as a result of recycling of divalent iron oxidized in the course of lipid peroxidation. The effects of rutin and dihydroquercetin on the liposomal CL in the presence of alpha-tocopherol and ascorbate in all experiments were almost the same as when these compounds were added individually. The antioxidant effects were merely summed up without any mutual enhancement or inhibition of each other's action.

Antioxidants↗
PubMed1999

[Serum antioxidative activity].

Model systems used in the determination of serum antioxidative activity (AOA), which differ both in the way of generating free radicals and in the mode of their detection, are clinically analyzed. The specific features and potentialities of the model systems developed at the authors' laboratory are characterized. These included yolk lipoprotein suspensions, liposomal suspensions formed from total phospholipid fraction, the hemoglobin-hydrogen peroxide-luminol system. The investigations show that most model systems for determining serum AOA contribute to the water soluble interceptors of free radicals (ascorbate, urate, plasma proteins, etc.), chelating and oxidative agents of catalytically active Fe2+ (ceruloplasmin, transferrin, albumin, etc.). The serum AOA levels measured with different model systems vary with the body's status. To determine serum AOA and the contribution of major endogenous antioxidants and inhibitors of free radical reactions may be a basis for the goal-oriented use of exogenous antioxidants in the therapy of a great variety of diseases.

Animals↗
PubMed1999

[Free radical mechanisms of low-intensive laser radiation].

A hypothesis of free radical mechanisms of stimulating action of low-intensive laser radiation (LILR) used for therapy of a variety of inflammatory diseases is formulated. The main points of the above hypothesis are as follows. Endogenous porphins are a LILR chromofor in the red band (lambda = 632.8 nm). Light absorption induces the production of initiating radicals that are involved in subsequent free radical reactions, in lipid peroxidation in particular. Modified lipid peroxidation in the cell membranes causes an increase in ion permeability, including that for Ca2+. The higher levels of Ca2+ in the leukocytic cytosol result in Ca(2+)-dependent cellular priming, which appeared as the increased cell functional potential and which is seen in subsequent leukocytic stimulation of the greater production of prooxidants and other biologically active products. These products include nitric oxide and a number of cytokines involved in the regulation of microcirculation. The paper presents experimental findings that can be regarded as evidence for some points of the above hypothesis which are used to provide a chain of events underlying the free radical mechanisms of stimulating action of low-intensive laser radiation.

Blood↗
PubMed1998

Effects of endogenous photosensitizers on the laser-induced priming of leucocytes.

The influence of He-Ne (lambda = 632.8 nm) laser irradiation on the functional activity of leucocytes was investigated. The functional activity of leucocytes irradiated in the presence of plasma with phthalocyanine raised. Irradiation of leucocytes without plasma had no influence on the chemiluminescent response of the blood cells. An increase in the concentration of phthalocyanine in plasma first led to an increase and then a decrease in the functional activity of the leucocytes. Similar results were obtained for the case of endogenous porphyrins in plasma. These results make it possible to consider the influence of laser irradiation on the leucocytes' functional activity as the priming. The basic concepts of the free-radical mechanism of laser therapy were formulated.

Free Radicals↗
PubMed1998

Low-power laser irradiation induces leukocyte priming.

Laser radiation (LR) of various spectral composition has been broadly used in clinical practice. However, the mechanism of the stimulating effects of LR remains obscure. The effect of He-Ne LR (633 nm) on human blood leukocytes was investigated both in the absence and presence of 8.65 nmol/l phthalocyanine (PhC). Irradiation of non-stimulated leukocytes with 0.025 to 0.5 J/cm2 did not lead to any activation of their luminol-dependent chemiluminescence (LCL). On the other hand, LR increased in most cases the subsequent CL response of the cells to opsonized zymosan (priming action of He-Ne-laser light). The effect of LR on the leukocytes was not standard. In irradiated leukocytes isolated from patients with severe acute or chronic pneumonia, or chronic bronchitis, the maximal LCL exceeded that for non-irradiated cells by 80% (0.05 J/cm2), 20-25% (0.15 J/cm2), and 0%, respectively (doses are shown in parentheses). Further increase of the exposure brought about a dose-dependent inhibition of LCL in cells from patients with severe acute and chronic pneumonia. There was an intriguing relationship between maximal CL responses of leukocytes subjected to laser irradiation in the presence and without PhC. When the priming effect of LR on isolated cells was small, it increased in the presence of exogenous photosensitizer, phthalocyanine; in cells of severely ill patients where the initial effect of LR was strong, Pc inhibited the priming action of LR. Apparently, different cells contained different amounts of endogenous photosensitizer(s); the addition of exogenous sensitizer increased the priming action of LR at low concentrations and decreased it at higher concentrations of the endogenous photosensitizer.

Bronchitis↗
PubMed1998

Hematoporphyrin derivative or phthalocyanine photosensitized hemolysis of erythrocytes under laser irradiation.

The effect of laser irradiation on the photosensitized hemolysis of rabbit erythrocytes was investigated. Two photosensitizers of domestic production were used: Photohem (a hematoporphyrin derivative) and Photosense (sulfonated phthalocyanine aluminium). The hemolysis was activated by laser irradiation in the presence of Photohem or Photosense. The process depended on the irradiation dose, the concentration of the photosensitizers and on the time during which the erythrocytes were incubated with the photosensitizers. Three lasers with wavelengths 520, 632.8 and 850 nm were used. The photosensitized hemolysis of rabbit erythrocytes was found to be inhibited by antioxidants.

Animals↗
PubMed1998

Effect of carnosine and its components on free-radical reactions.

The antioxidant properties of carnosine and its components histidine and beta-alanine were compared using several model systems: glutathione-horseradish peroxidase-luminol (GSH-HRP-luminol), xanthine-xanthine oxidase (X-XO), stimulated human blood polymorphonuclear leukocytes (PML), and egg yolk phospholipid liposomes in the presence of Fe2+ ions. Carnosine and histidine (30-40 mM) were shown to cause 50% suppression of free radical reactions in the GSH-HRP-luminol system, whereas beta-alanine displayed no activity. The O(2-)-scavenging activity of carnosine in the X-XO system was demonstrated; 50% inhibition was achieved at 7.1 x 10(-5) M. Suppression of the luminol-dependent PML chemiluminescence by carnosine and reduction of the latent period of the Fe(2+)-induced chemiluminescence of the liposome suspension was suggested to demonstrate its ability to interact with Ca2+ and Fe2+ ions. This was confirmed by the o-phenanthroline test. The results obtained demonstrate that carnosine is capable of scavenging different radicals and binding divalent metal ions. The antioxidant activity of carnosine was observed in all the systems studied, and carnosine effective concentrations corresponded to those found in the brain and muscles. The universal effects of carnosine and its high concentration in excitable tissues suggest this dipeptide to be an inhibitor of free radical reactions in vivo.

Antioxidants↗
PubMed1998

Effect of antioxidants on the kinetics of chain lipid peroxidation in liposomes.

To elucidate the mechanism of action of various antioxidants, we studied the kinetics of chemiluminescence which accompanies the peroxidation of phospholipid liposomes as induced by divalent iron ions in the presence of C-525, a chemiluminescence activator. EDTA and desferal reduced the chemiluminescence latent period, probably, due to the chelation of Fe2+ ions which, thus, dropped out of chain oxidation reactions in the lipid phase. In contrast, ascorbate increased the chemiluminescence latent period, apparently, as a result of regeneration of divalent iron oxidized during lipid peroxidation. alpha-Tocopherol and rutin reduced the amplitude of the chemiluminescence slow flash and increased the duration of the latent period. beta-Carotene displayed its effect only at rather high concentrations, when the decrease in chemiluminescence intensity could be due (at least partially) to the reabsorption of chemiluminescence by this compound. The latent period remained invariable in this case.

Animals↗
PubMed1998

The antioxidant properties of lycopene.

The antioxidant properties of the carotenoid lycopene were compared in three different model oxidative systems. In egg yolk liposomes, in the presence of 2.5 mM FeSO4 and 200 mM ascorbate, lycopene, alpha-tocopherol, and beta-carotene inhibited the accumulation of lipid peroxidation products reacting with 2-thiobarbituric acid (TBARS) in a dose-dependent mode, with the concentration of half-inhibition being 80, 30 and 130 mM, respectively. In the liposomes subjected to illumination with a He-Ne laser (632.8 nm) at a dose of 10.5 J/cm2, in the presence of 32.5 micrograms/ml hematoporphyrin derivatives (Fotogem, NIOPIC, Russia) TBARS accumulated, and this effect was inhibited by lycopene, alpha-tocopherol, and dihydroquercetin with approximately equal efficiencies (the half-inhibition concentrations were 10(-5) mM). In both systems studied, sodium azide at a concentration of 10 mM inhibited the TBARS accumulation by no more than 20%. Apparently, the inhibitory action of not only alpha-tocopherol, but also beta-carotene and lycopene was the result of their antiradical action, rather than quenching of the singlet oxygen in an aqueous medium. The introduction of lycopene, as well as beta-carotene in liposomes subjected to Fe(2+)-induced lipid peroxidation decreased the chemiluminescence (CL) intensity at the stage of CL slow flash, with no essential influence on the lag period. These data suggest that the effect of lycopene on lipid peroxidation was the result of its interaction with free radicals rather than chelating ferrous ions. The antiradical activity of lycopene was also confirmed by the method of luminol photochemiluminescence (PCL). Lycopene increased the PCL lag period (L) and decreased the PCL amplitude (A), which implies its antiradical and SOD-like activity in this system.

Animals↗
PubMed1997

Evidence for a direct interaction of superoxide anion radical with carnosine.

Using photochemiluminescence, the interaction between carnosine and superoxide anion was measured directly. Carnosine at physiological concentrations decreased the amplitude of luminol chemiluminescence like superoxide dismutase (SOD) did, and prolonged the lag-period of the chemiluminescence similar to the effect of ascorbic acid. From the interaction of nitro blue tetrazolium with superoxide anion generated by the xanthine oxidase system, the constant for interaction of carnosine with 02-. was calculated to be 10(5) M-1.sec-1. The possible biological significance of the quenching of superoxide anion by carnosine is discussed.

Carnosine↗
PubMed1991

Priming of phagocytes by cytokines and water-soluble products of lipid peroxidation.

It is well known that during certain pathological processes phagocytes acquire the ability to generate activated oxygen species during phagocytosis. The priming of phagocytes by cytokines and water-soluble products of lipid peroxidation (LPO) is described. Preincubation of human polymorphonuclear leukocytes (PMNL) with the water-soluble products of LPO or oxidised liposomes for 15-20 min at 37 degrees C enhanced their functional activity when they were stimulated by opsonised zymosan or latex particles. There was a 2-3-fold increase in luminol-dependent chemiluminescence response of cells stimulated in this way, and an increase in Fc-receptor expression on the PMNL surface. An endogenous cytokine alone did not activate the phagocytes for an oxidative burst response, but preincubation of murine peritoneal macrophages (MP) and human PMNL with cytokines (molecular mass 20-30 kDa) for 3-48 h at 37 degrees C enhanced the cell chemiluminescence response to opsonised zymosan by a factor of 5-9 for MP and a factor of 2-3 for PMNL. Treatment of phagocytes with the cytokine complex also increased other effector functions of the phagocytes such as tumouricidal activity, phagocytosis, secretion of interleukin-1, and antiparasitic activity. The protein synthesis inhibitor cycloheximide abolished cytokine-induced priming of MP (but not of PMNL). The mechanisms of short-term and prolonged priming of the two types of phagocytes (MP and PMNL) are discussed.

Animals↗