pH-Dependent Changes in the Mechanisms of Transport of Chlorine e6 and Its Derivatives in the Blood.

We studied the effects of medium pH on steady-state distribution of chlorine e6 and its derivatives between the main transport proteins of human blood plasma. The decrease in medium pH from weakly alkaline (pH 7.4) to acid (pH 5.0) was followed by an increase in relative affinity of chlorines to lipoproteins and reduced their affinity to serum albumin. pH-Dependent changes in the parameters of distribution of photosensitizers between the plasma and blood cells was revealed. We discussed the role of charge and polarity degree of photosensitizer molecule in the mechanism of binding to serum albumin. A possible role of changes in hydrogen ion activity in the processes of selective accumulation of chlorines by tumor cells is discussed.

[Evaluation of Photo- and Cytotoxicity of Chlorin e6 Ester Derivatives and Their Liposomal Forms].

Photophysical characteristics and photosensitizing activity of the chlorin e6 dimethyl and trimethyl ester derivatives in various solution and their liposomal forms were studied. It was shown that in lipid vesicles chlorin e6 ester derivatives are predominantly in the monomeric state and possess optimal photophysical properties and high photochemical activity. The rate of redistribution of the chlorin e6 dimethyl ester from lipid vesicle to cells was higher as compared with that one of the chlorin e6 trimethyl ester. The increase of the serum concentration in the incubation medium has a different effect on processes of accumulation of the liposomal forms of the chlorin e6 dimethyl and trimethyl ester derivatives by the cells. Cell culture studies showed that application of liposomal forms of the chlorin e6 dimethyl and trimethyl ester derivatives significantly decreases their cytotoxicity but keeps high cytotoxic effect of photodynamic activity of the chlorin e6 ester derivatives.

Comparative analysis of accumulation of chlorine e6 and hematoporphyrin derivatives in subpopulations of peripheral blood lymphocytes.

We studied accumulation of porphyrin photosensitizers chlorine e6, hematoporphyrin, and their derivatives by different lymphocyte subpopulations. The intensity of staining of B lymphocytes and natural killer cells with photosensitizers was higher compared to T lymphocytes. T cell subpopulation differed by their ability to bind photosensitizers. Relative accumulation of dimethyl esters of chlorine e6 and hematoporphyrin in cells surpassed that of nonesterified porphyrins.

[Selectivity of accumulation of chlorine e6 derivatives in blood leukocytes]. / Selektivnost' nakopleniia proizvodnykh khlorina e6 v leikotsitakh krovi.

The uptake of chlorine e6 derivatives by peripheral blood leukocytes was studied using a fluorescence-activated sorter. The analysis showed that the order of pigment uptake by leukocyte populations is the following: granulocytes > or = monocytes > lymphocytes. It was found that the accumulation of the pigments in the cell significantly varied. The level of chlorine e6 dimethyl ester accumulated by cells was found to be 15 times higher than that of chlorine e6. It was assumed that the differences in pigment uptake by different types of blood cells are due to structural and morphological features of leukocytes. The data obtained may be useful in developing the new methods of photodynamic therapy.

[Distribution of porphyrin sensitizers among protein and cellular blood elements]. / Raspredeleniie porfirinovykh sensibilizatorov mezhdu belkovymi i kletochnymi élementami krovi.

The distribution of porphyrin pigments between plasma proteins and blood cells was studied. It was shown that the relative fraction of sensitizer bound by blood cells changed significantly depending on the physicochemical features of pigment molecules. This parameter strongly correlates with porphyrin polarity. Polar watersoluble tetraphenylporphin derivatives, chlorine e6 and hematoporphyrin are bound by plasma proteins only. The decrease in pigment polarity by substitution of polar side groups results in a drastic increase of pigment affinity to blood cells. The binding of extremely apolar pigments by cells in blood occurs for a long period of time, probably as a result of a low rate of pigment redistribution between serum proteins and cellular membrane. The data obtained show that blood cells may be involved into the control of pigment transport and distribution in organism during photodynamic therapy. The parameters of porphyrin distribution between plasma proteins and cells in blood are of certain importance when the pharmacokinetic behavior of various sensitizers is compared.

[Combined effect of visible light sensitized by chlorine e6 and streptomycin on the obligate pathogenic bacterium Klebsiella rhinoscleromatis]. / Kombinirovannoe sensibilizirovannoe khlorinom e6 deistvie vidimogo sveta i streptomitsina na obligatno-patogennye bakterii Klebsiella rhinoscleromatis.

Chlorine e6-sensitized photodamage of Klebsiella rhinoscleromatis (an obligate pathogen) in the presence of streptomycin was studied. The pathogen is highly resistant to photosensitization characteristic of other gram-negative bacteria. Marked synergism of the bactericidal effect of the chlorine e6-sensitized visible light and streptomycin on K. rhinoscleromatis was observed. It was suggested that the synergistic action was due to the oxidative damage of the cell membranes resulting in higher rates of the streptomycin penetration to the cells and impairment of the intracellular protective mechanisms at the molecular level. The findings are in favour of the further investigation aimed at the development of a comprehensive method of photo- and chemotherapy of scleroma.

[The free-radical mechanisms of the cytotoxic action of 1,2-benzoquinone derivatives]. / Svobodnoradikal'nye mekhanizmy tsitotoksicheskogo deistviia proizvodnykh 1,2-benzokhinona.

The authors examined the interaction of 1,2-benzoquinone derivatives with HeLa cell cultures and ascite Ehrlich's cancer cells. 4-N (anilino)-5-methoxy-1,2-benzoquinone was found to produce a marked toxic effects against tumor cells. The cytotoxic effect is oxygen dependent and associated with the formation of oxygen radicals in quinone's redox cyclization reactions. The inhibitory analysis was used to show that the major mediators of the toxic action of the agent are superoxide radical-anion and hydrogen peroxide. It is concluded that the interaction of highly toxic oxygen radicals, which are generated in quinone redox cyclization, with plasma membrane cells is likely to be the mechanism responsible for cellular destruction when quinones act on tumor cells.

[A comparative study of the reactions of the peripheral blood neutrophils from donors and from lymphogranulomatosis patients to arachidonate stimulation of the cells]. / Sravnitel'noe issledovanie reaktsii neitrofilov perifericheskoi krovi donorov i bol'nykh limfogranulematozom pri stimuliatsii kletok arakhidonatom.

Arachidonate-induced aggregation and generalization of active oxygen forms (OAF) by peripheral blood neutrophils in donors were studied in donors and Hodgkin's disease patients. Leukocytes of the latter had incomplete ability to produce AOF in response to cell stimulation with arachidonic acid. The study of arachidonate-induced aggregation of neutrophils indicated no differences in the speed of the process in the patients and donors. AOF catchers did not act on the rate of leukocyte aggregation in the patients though accelerated the process in the donors. It is inferred that Hodgkin's disease is associated with dysfunction of oxygen activation by neutrophils. The findings suggest that defects in leukocytes ability to activate oxygen in Hodgkin's disease may entail deranged regulation of other processes essential for functional activity of polymorphonuclear leukocytes.

[Photodamage of gram-positive and gram-negative bacterial cells in the presence of chlorin e6 derivatives]. / Fotopovrezhdenie grampolozhitel'nykh i gramotritsatel'nykh bakterial'nykh kletok v prisutstvii proizvodnykh khlorina e6.

The kinetics of photoinduced damage sensitized by chlorine e6 and its derivatives was studied in Escherichia coli and Bacillus subtilis. The effectiveness of E. coli photoinactivation in the presence of chlorines was 100-200 times lower as compared with that of B. subtilis. The structural organisation of bacterial cell walls apparently played an essential role in the penetration of tetrapyrrole pigments into the cell and in their binding.

[Arachidonic acid-induced aggregation of human peripheral blood neutrophils in the presence of interceptors of active forms of oxygen]. / Arakhidonatindutsirovannaia agregatsiia neitrofilov perifericheskoi krovi cheloveka v prisutstvii perekhvatchikov aktivnykh form kisloroda.

Arachidonate-induced aggregation of human peripheral blood neutrophils and the influence of certain interreceptors of oxygen active forms (OAF) on its rate were studied. The results obtained have shown that OAF play an important role in the processes of interaction between arachidonate and leucocytes. Regulation of the process of leucocyte aggregation may be realized during arachidonate-induced aggregation of neutrophils, due to interaction of cell-generated OAF with arachidonic acid and its lipoxygenase metabolites.

[Modification of redox properties of cells by ortho-benzoquinones]. / Modifikatsiia okislitel'no-vosstanovitel'nykh svoistv kletok ortobenzokhinonami.

Ortho-benzoquinones have been studied for their effect on the processes of methemoglobin formation in the rabbit erythrocytes and reduction of potassium ferricyanide by the HeLa cells. It is established that the incubation of cells in the presence of lipophilic quinone OBQ-1 results in the formation of the intracellular methemoglobin in erythrocytes and the intensification of the ferricyanide reduction by HeLa cells. OBQ-2 differing in the presence of the polar sulphogroup does not react with the intracellular oxyhemoglobin and exerts no effect on the ferricyanide reduction. It is supposed that OBQ-1 may change the ratio of the oxidized and reduced metabolites in a cell, thus inducing in it a state of the oxidative stress. A conclusion is drawn hat ortho-benzoquinones are able to modify the redox properties of cells, the efficiency of modification depending on the chemical structure of the compounds.

[Photosensitization by chlorine and porphyrin causing structural damage of erythrocytes]. / Fotosensibilizirovannye khlorinami i porfirinami structurnye povrezhdeniia éritrotsitov.

Kinetics of hemolysis of human erythrocytes photosensitized by porphyrin and chlorin derivatives was investigated by small angle light scattering method. The compounds used were arranged in the following order of photosensitizing activity decrease: ethylendiamide of chlorine e6, chlorine e6 dimethylester chlorine e6 haematoporphyrin diacetate tetracarboxyphenylporphyn. The substances having a greater number of binding sites with liposomes (chlorine e6 dimethylester) or with albumin (ethylendiamide of chlorine e6) showed the greatest photohemolytic activity. The photohemolytic activity of porphyrins was suggested to depend on the number of the pigment molecules bound by erythrocytes membranes.

[Effect of concanavalin A on the level of sulfhydryl groups in thymocytes]. / Vliianie konkanavalina A na soderzhanie sul'fgidril'nykh grupp v timotsitakh.

Fluorescein mercury acetate (FMA), a fluorescent probe, is used for the investigation of SH-groups of thymocytes' plasma membrane. It is found that mitogenic lectin Con A decreases the amount of membrane SH-groups and increases the fluorescence polarization degree of FMA (PFMA). The value of PFMA increases also during the incubation of cells with potassium ferricyanide and H2O2 but it decreases in the presence of NADH. The analysis of the data permits a conclusion that the thymocyte activation by Con A results in the selective oxidation of certain SH-groups with the formation of disulphide cross-linking between the plasma membrane receptors bound with the lectin molecules.

[Production and study of therapeutic proton beams on the remodeled phasotron]. / Poluchenie i issledovanie terapevticheskikh protonnykh puchkov na rekonstruirovannom fazotrone.

The first results of the formation and transportation of therapeutic proton beams at the JINR phasotron are presented. To ensure flat-top depth-dose distributions with a steep back slope, a method of forming a beam with a necessary energy spectrum from a non-monoenergic beam is employed. Extension of the flat hop of depth-dose distribution is 4.7 g/cm2 for a proton beam with the mean energy of 200 MeV.

[Measuring equipment for communication with a computer]. / Izmeritel'naia apparatura na sviazi s EVM.

A brief consideration of the hardware and software of the automated control system for proton beam therapy in the clinicophysical complex at the JINR Laboratory of Nuclear Problems is presented.

[Changes in the activity of hydrogen ions in lymphocytes during the endocytosis of concanavalin A]. / Izmenenie aktivnosti ionov vodoroda v limfotsitakh pri éndotsitoze konkanavalina A.

Changes of hydrogen ions activity in rat thymocytes were studied during the process of concanavalin A (Con A) endocytosis by cells. A possibility was shown to use fluoresceinisothiocyanate-labeled Con A for measuring pH values in the sites of mitogen localization. It is established that during the action of Con A endocytotic vesicles with low pH value are formed, while the pH value of the cytoplasm is increased. The pH value measured in the sites of mitogen localization depends on the treatment of cells by alpha-methyl-D-mannoside and sodium azide. Mechanisms of acidic-basic equilibrium changes in the cytoplasm of lymphocytes upon cell stimulation with mitogens are discussed.

[The effect of concanavalin A on the thymocyte intracellular pH]. / Vliianie konkanavalina A na vnutrikletochnuiu velichinu pH timotsitov.

The effect of different concentration of concanavalin A on intracellular pH of rat thymocytes has been studied by means of fluorescent probe 9-aminoacridine. It has been shown that the addition of mitogen to cells results in an increase of pH value inside the thymocytes. The value of pH changes depends on the concentration of concanavalin A.