[Liposomal form of lipoic acid: preparation and determination of antiplatelet and antioxidant activity]. / Liposomal'naia forma lipoevoi kisloty: poluchenie i opredelenie antiagregatsionnoi i antioksidantnoi aktivnosti.

Optimal conditions for obtaining phosphatidylholine (PC) liposomes with lipoic acid (LA) are chosen that lead to the formation of nanoparticles with a size of 175¸284 nm with efficiency (extent) of inclusion of LA in liposomes equal 85% and characterized by a slow release of substance from the nanoparticles. The effect of "empty" liposomes and liposomal form of LA on platelet aggregation induced by arachidonic acid (AA) is established. It is found that liposomes with LА inhibit platelet aggregation, caused by AА, to 80%. In addition, it is shown that "empty" liposomes slightly (to 30%) suppress platelet aggregation, caused by AА. The amount of TBA-sensitive products in samples of platelet-rich plasma (PRP) incubated with liposomal LA is determined. It is shown that LA in the composition of liposomes retains its antioxidant properties, and the amount of products of lipid peroxidation in platelet-rich plasma decreases in a dose-dependent manner when arachidonic acid is used as an inductor of platelet aggregation. It is assumed that the antiplatelet action of the liposomal form of LА is induced by inhibition of the initiation of lipid peroxidation products caused by exogenous inducer AА. It is supposed that, after additional research, the liposomal form of LA can be considered as a new drug in complex treatment of cerebral ischemia.

[Study of the influence of gold nanoparticles on activation of human blood neutrophils].

Activation of neutrophils in the presence of gold nanoparticles is accompanied by the formation of free radical peroxidation products recording the flash of chemiluminescence. The basis for the activation mechanism has its origins most likely in the influence of the gold particles on the surface membrane potential of neutrophils. Investigation of changes in the fluorescence intensity of the negatively charged ANS probe on the surface of model membranes by adding different concentrations of gold nanoparticles indicates the change in the membrane surface charge density that can cause cell activation.

[The interaction of hypochlorite with fatty acid hydroperoxides results in the generation of free radicals].

The interaction of hypochlorite with linoleic acid hydroperoxides was studied by the coumarin C-525-enhanced chemiluminescence and ESR spin trapping techniques. Linoleic acid hydroperoxide was obtained in the reaction of lipoxygenase and linoleic acid. Alpha-(4-pyridyl-1-oxyl)-N-tert Butylnitron was used as a spin trap. It was shown that the addition of hypochlorite to the incubation media containing linoleic acid and lipoxygenase resulted in an intensive chemiluminescence flash. The intensity of this flash correlated with the hydroperoxide concentration. The analysis of ESR spectra of spin adducts produced in the reaction of hypochlorite with linoleic acid hydroperoxide showed the presence of O-centered, most likely peroxyl, radical with the splitting constants alphabetaH = 0.260 mT aN = 1.662 mT and C-centered penthyl radical with the splitting constants alphabetaH = 0.260 mT; aN = 1.662 mT. These data suggest that hypochlorite produced by phagocytes in vivo can induce the generation of free O- and C-centered radicals, promoters of free radical processes.

[Interaction of tert-butyl hydroperoxide with hypochlorite induces peroxyl radicals. A chemiluminescence study]. / Vzaimodeistvie tret-butilgidroperoksida s gipokhloritom privodit k obrazovaniiu perekisnykh radikalov. Issledovanie metodom khemiliuminestsentsii.

The interaction of hypochlorite (HOCl/OCl-) with tert-butyl hydroperoxide ((CH3)3COOH) was investigated by chemiluminescence. It was shown that the addition of HOCl/OCl- to (CH3)3COOH induces a fast chemiluminescent flash. The intensity of this flash increases with the increase in both HOCl/OCl- and (CH3)3COOH concentration. The chemiluminescence is quenched in a concentration-dependent manner in the presence of free radical spin traps N-tert-butyl nitrone and alpha-(4-pyridyl-1-oxyl)-N-tert-butyl nitrone. This fact proves that free radicals take part in the interaction of HOCl/OCl- and (CH3)3COOH. Hypochlorite yielded a very similar chemiluminescence spectrum in its reaction with (CH3)3COOH as Ce4+. It differed considerably from the spectrum in the system H2O2 and HOCl/OCl-. It is well known that the interaction of Ce4+ and (CH3)3COOH produces peroxyl radicals. These results confirm the hyothesis that the interaction of HOCl/OCl- and (CH3)3COOH is mediated by peroxyl radicals. Thus, organic hydroperoxides always present in unsaturated lipids can induce lipid peroxidation processes in the reaction with HOCl/OCl-.

[Nitric oxide, hemoglobin and laser irradiation]. / Oksid azota, gemoglobin i lazernoe obluchenie.

The paper deals with the present views of some chemical properties and biological effects of nitric oxide (NO) and chiefly its formation and primary conversions. The interaction of NO with superoxide radical is shown to one of the most important reactions of the former, which gives rise to peroxynitrite whose breakdown yields a hydroxy radical. Emphasis is laid on the substances that are a temporary depot or a possible transport form of NO, such as nitrosothiols and nitrosyl complexes of non-hemic iron. NO is well-known to release when these compounds are degraded. It is suggested that hemoglobin is another NO depot, which forms stable complexes with the latter. These hemoglobin complexes may be degraded on exposure to laser radiation to form free NO that ha a vasodilatory effect. Photolysis of nitrosyl complexes of hemoglobin may be responsible for the therapeutical effect of laser radiation.

Photochemical reactions of nitrosyl hemoglobin during exposure to low-power laser irradiation.

Relaxation of blood vessel walls is one of the physiological effects induced by visible radiation. This effect is similar to the endothelium-derived relaxation (based on endothelium-derived relaxing factor, EDRF) and depends on the presence of nitric oxide donors. We assumed that nitric oxide hemoglobin (HbNO) might participate in the mechanism of this phenomenon and investigated the photochemical reactions using low-power He-Cd (441.6 nm) and He-Ne (632.8 nm) lasers. It was found that in the presence of oxygen the He-Cd laser but not He-Ne laser induced a photolytic decrease of the HbNO EPR signal amplitude by 25-35%. Using optical absorption measurements, we showed that methemoglobin was formed during irradiation. The comparison of the kinetics of this process and the irreversible reduction of paramagnetic centers suggest that the laser radiation leads to dissociation of the heme-NO complexes, but not to oxidation of the heme iron. In the absence of oxygen the photodissociation effect did not exceed 5-10% and was reversible. We suppose that this finding can be explained by fast reassociation of NO with unligated Hb. The EPR spectrum of iminonitroxide was observed upon irradiation of HbNo with nitronyl nitroxide in a vacuum, suggesting the formation of free NO. Thus, our experiments confirm that NO-hemoglobin can reversibly dissociate and release free NO during exposure to He-Cd laser radiation.

[Mechanism of human blood neutrophil activation by electric field pulses]. / Mekhanizm aktivatsii neitrofilov krovi cheloveka impul'sami élektricheskogo polia.

High voltage electric field pulses, was shown previously, induced activation of blood neutrophil respiratory burst, registered as increase in luminol-dependent chemiluminescence of cell suspension. The quantitative analysis of this phenomenon by fluorescent probes and radioisotope methods have shown that electric pulse induced neutrophil chemiluminescence is a result of Ca2+ ions entering the cells through reversible pores in plasma membrane. Electric pulse of amplitude 5 kV/cm generates two tens of reversible pores with average diameter nearly 2 nm and lifetime 1 minute. Total amount of calcium penetrating at this conditions from the medium (1 mM Ca2+) into the cells was as high as 1.2 fmole/cell that is nearly 3.6 mM concentration per cell volume. Whereas the increase in the cytoplasmic concentration of free calcium did not exceed 1.3 microM, that is more then 3 order less. Data presented is discussed with relation to possible biological role of electroporation by natural electric fields presented in living systems.

[The effect of continuous millimeter low-intensity radiation on the Na+ ion transport in the frog skin]. / Vliianie nepreryvnogo millimetrovogo izlucheniia nizkoi intensivnosti na transport ionov Na+ v kozhe liagushki.

Many data on the effect of millimeter (MM) radiation of low intensity (of the order of 1 mVt/cm2) on living organisms were accumulated [1]. The specifics of this effect is first of all manifested in frequency--selective (resonance) pattern of the biological system response and the effect of threshold dependence of exposition time and power of MM radiation. To study the mechanism of this effect it seems perspective to investigate the influence of radiation on the membrane transport. The present work investigated the effect of MM radiation on a comparatively simple and well investigated object--isolated frog skin.