[Study of the neuroprotective action of hybrid structures based on fullerene C60].

The neuroprotective action of hybrid structures based on fullerene C60 with attached proline amino acid has been studied. Hybrid structures contained natural antioxidant carnosine or addends with one or two nitrate groups. It has been shown that all studied compounds had antioxidant activity and decreased the concentration of malondialdehyde in homogenates of the rat brain. Compound 1, which contained the antioxidant carnosine, has been found to be the most effective antioxidant. All compounds except IV and V inhibited the activity of monoamine oxidase B, while compounds I-IV increased the activity of monoamine oxidase A. All investigated compounds inhibited glutamate-induced Ca2+ uptake into synaptosomes of the rat brain cortex. Compound III, containing two nitrate groups, has been found to be the most effective inhibitor. This compound caused a significant increase of the currents of AMPA receptors (AMPA, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid).

[Ecotoxicological value of sediments state from reservoir R-11 of Techa River reservoir cascade].

Researches of sediments state from reservoir R-11 of tandem Techa river reservoir cascade were made. Shershni (Shershni's reservoir, Chelyabinsk region) was used as reference reservoir. Radiochemical analysis of sediments and water from those reservoirs were made (radioactivity in sediments of R-11 ranged from 240 to 360 kBq/kg of dry weight for 90Sr and from 10 to 161 kBq/kg of dry weight for 137Cs). Hydrobiological researches were included (1) detection of quantitative progress and species composition of Oligochaeta fauna in reservoirs and (2) bioassay of sediments in laboratory conditions with using test-organisms Tubifex culture. Calculation of absorbed dose for Oligochaeta from reservoir R-11 was performed on basis of radiochemical analysis data. Our results indicated that quantitative progress of Oligochaeta in reservoir R-11 was less then progress in Shershni's reservoir. R-11 sediments bioassay did not show any toxic effect by tubificidae in laboratory experiments. Significant dependence for quantitative progress Oligochaeta in reservoir R-11, survival rate and breeding power from absorbed dose rate weren't found. However in subacute research breeding power for animals with higher radiation (absorbed) dose was reduced.

[Anticonvulsants as bioantioxidants under stress conditions].

The action of heterocyclic amides series (ethosuximide, phenytoin, primidone) on lipid peroxidation and membrane bound monoamine oxidases A and B under stress condition has been studied. The intraperitoneal injection of the drugs resulted in enhancement of SOD, decrease of brain malondialdehyde content and mitochondrial activity of monoamine oxidases A and B.

[The inhibitor of free radical processes decrease of protein biosynthesis in gun short wound tissues and weaken development of the general adaptation syndrome].

The dynamics of total protein biosynthesis and procollagen biosynthesis in skeletal muscle of injury tissues with the antioxidant BHT (dibunol) treatment and with common healing were studied. The obtained date indicate that the AO treatment reduce the rate of biosynthesis both the total proteins and procollagen at the 3th day of healing. Dibunol also considerably reduce the protein biosynthesis in adrenals and brake of corticosteroids biogenesis as measured by ESR-signals intensity of reduced adrenodoxine. AO treatment also reduce the protein biosynthesis in thymus, spleen and bone marrow. The lowering of functional activity of endocrine and immune systems indicate that the AO significantly inhibit the systemic reactions of organism induced by acute wound affect. It was suggested that as "primary mediator" of stress-reaction may be considered lipoperoxide radicals and decay products of lipohydroperoide.

[Inhibition of active transport of calcium ions by PT(IV) and PD(II) metal complexes. Correlation between the process and antimetastatic action of drugs].

Newly synthesized compounds, namely, platinum and palladium metal complexes based on substituted pyridinecarboxylic acids inhibit both active transport of Ca ions and hydrolysis of ATP, catalyzed by sarcoplasmic reticulum Ca(2+)-ATPase. The degree of active transport of Ca ions to vesicles correlated to the inhibition of metastases of experimental melanoma B16 by compounds studied. We suggest that the mechanism responsible for inhibition of metastases by newly synthesized compounds consists in change of normal ratio of extra- and intracellular content of Ca2+ ions that influences platelet aggregation, required for adhesion of metastasizing tumor cells to vascular walls.

[Modulation of reactivity of cyclic adenosine monophosphate phosphodiesterase under the effect of pyridinecarboxylic acid derivatives and Pt(IV) metal complexes on their basis].

The effect of substituted nicotinamides and isonicotinamides and Pt(IV) metal complexes based on the substituted nicotinamides and isonicotinamides on the activity of cAMP phosphodiesterase was studied. Isonicotinamide derivatives are efficient enzyme activators, whereas substituted nicotine amides are inhibitors of enzymatic cAMP phosphodiesterase activity; their inhibitory potency is comparable to that of theophylline used as a reference drug.

Brachytherapy after laser recanalization versus external beam radiotherapy after laser recanalization versus laser alone in inoperable oesophagocardial cancer: a controlled pilot study.

PURPOSE: To compare the results of combined laser/radiation therapy with laser treatment alone, and to evaluate the potential benefit of brachytherapy vs. external beam radiotherapy after laser recanalization in patients with dysphagia due to oesophagocardial cancer. PATIENTS AND METHODS: Twenty patients with grade 4 malignant dysphagia caused by oesophagocardial cancer underwent Nd: YAG laser desobstruction up to grade 0-1. Ten of them were referred afterwards for external beam radiotherapy at a dose of 30 Gy for 10 sessions, while the remaining were administered endocavitary afteloading brachytherapy at a dose of 2x7.5 Gy. Twenty preselected patients (to maximally match the above group), who successfully underwent laser re-establishment of the continuity, served as controls to the groups described. Criteria for evaluation were: mean interval to re-stenosis, mean number of additional laser procedures needed, mean survival and Karnofski's performance status (PS). Patients were followed to death. Statistical analysis was carried out with the Student's t-test. RESULTS: It was found that laser plus brachytherapy increased almost 3 times the interval to re-stenosis and decreased almost 2 times the need of additional laser usage in comparison to laser alone. It was also found that laser plus brachytherapy is statistically superior option to laser plus external beam radiotherapy. CONCLUSION: Laser plus brachytherapy has the potential to become a single modality-single session treatment for the relief of dysphagia in patients with stage IV oesophagocardial cancer.

[On the influence of silicate feeding on metabolism of 137Cs in rabbit]. / O vliianii kormovogo ispol'zovaniia silikatov na metabolizm 137Cs v organizme krolikov.

The features of 137Cs metabolism in the rabbit's organism when feeding on silicates were investigated. By results of two experiments on rabbits radiosorption by of zeolite, saponit, humolit, vermiculite and palygorskit in the gastrointestinal tract was evaluated. It was found that vermiculite and palygorskit had the strongest influence on processes of accumulation and decorporation 137Cs, when a dose of additives was 5% of the weight of forage.

[Railway use of asbestos-containing rubble: environmental hygienic aspects]. / Ekologo-gigienicheskie aspekty primeneniia asbestsoderzhashchego ballasta na zheleznykh dorogakh.

The paper presents the results of a study of the gravimetric and counting concentrations of respirable asbestos fibers while working with sand-and-crushed stone mixtures, obtained from the concentration of chrysotile asbestos, at distances of 25, 50, and 100 m from the working place, as well as in a car saloon when the electric train passes along the area of these operations following an hour, a day, and a year after the completion of work, in warm and colds seasons of a year. It is concluded that the use of asbestos-containing sand-and-crushed stone mixtures on the railway leads to a higher anthropogenic asbestos load on the population living in the railway right-of-way, on railway workers and passengers. In this connection, it is necessary to evaluate risk factors of asbestos-induced diseases among the above contingents. The authors consider that due to the fact that asbestos-containing sand-and-crushed stone mixtures are well wetted with water, followed by the formation of a firm surface crust that prevents dust formation, as well as the short duration and rare frequency of operations relating their change, it is necessary to irrigate the repair areas with water or surfactant liquids after work termination.

Coupled microstrip line transverse electromagnetic resonator model for high-field magnetic resonance imaging.

The performance modeling of RF resonators at high magnetic fields of 4.7 T and more requires a physical approach that goes beyond conventional lumped circuit concepts. The treatment of voltages and currents as variables in time and space leads to a coupled transmission line model, whereby the electric and magnetic fields are assumed static in planes orthogonal to the length of the resonator, but wave-like along its longitudinal axis. In this work a multiconductor transmission line (MTL) model is developed and successfully applied to analyze a 12-element unloaded and loaded microstrip line transverse electromagnetic (TEM) resonator coil for animal studies. The loading involves a homogeneous cylindrical dielectric insert of variable radius and length. This model formulation is capable of estimating the resonance spectrum, field distributions, and certain types of losses in the coil, while requiring only modest computational resources. The boundary element method is adopted to compute all relevant transmission line parameters needed to set up the transmission line matrices. Both the theoretical basis and its engineering implementation are discussed and the resulting model predictions are placed in context with measurements. A comparison between a conventional lumped circuit model and this distributed formulation is conducted, showing significant departures in the resonance response at higher frequencies. This MTL model is applied to simulate two small-bore animal systems: one of 7.5-cm inner diameter, tuned to 200 MHz (4.7 T for proton imaging), and one of 13.36-cm inner diameter, tuned to both 200 and 300 MHz (7 T).

[Content of asbestos fibers in water sources of the Bazhenovo deposit]. / Soderzhanie volokon asbesta v vodoistochnikakh Bazhenovskogo mestorozhdeniia.

The paper provides preliminary measurements of asbestos levels in water sources from an area of the Bazhenovo chrysotile-asbestos deposit. All study water samples have been found to contain chrysotile-asbestos fibers at concentrations one-three orders less that the values standardized in the USA (7 x 10(6) vol/l). The authors consider it advisable to continue studies to measure asbestos levels in the water sources in the areas in vicinity of other Russian deposits.

[Sanitary characteristics of the production of asbestos membranes]. / Gigienicheskaia kharakteristika proizvodstva asbestovykh membran.

The paper presents preliminary results of sanitary assessment of the production of asbestos membranes. The production may emit highly disperse asbestos-containing aerosols of disintegration with low levels of filamentous particles and respirable fibers of chrysotile-asbestos into the air of working areas. It is concluded that latest chrysotile-asbestos processing is not a significant source of air pollution in the working areas where asbestos-containing and related noxious substances are present.

[Structural-functional changes in biomembranes during complications of diabetes mellitus and their pharmacological correction]. / Strukturno-funktsional'nye izmeneniia biomembran pri oslozhneniiakh sakharnogo diabeta i ikh farmakologicheskaia korrektsiia.

The decrease of sorbitol dehyidrogenase activity and the increase both of aldoso reductase activity and sorbitol concentration in aorta or eye lens under experimental diabetic angiopathy have been shown. The structural and functional alterations in erythrocytes membranes under angiopathy studied by spin- and luminesoense probes confirm the hypothesis on the major role of membrane pathology processes in the pathogenesis of diabetic mellitus. Pharmacological correction of diabetic angiopathy by glucophag or new antioxidant LBK-78 normalized the studied diversions on the membranes level.

Membranotropic properties of the water soluble amino acid and peptide derivatives of fullerene C60.

The modifying effects of the products of the equimolar addition Of DL-alanine and DL-alanyl-DL-alanine to fullerene C60 on the structure and permeability of the lipid bilayer of phosphatidylcholine liposomes has been studied using the luminescence probe technique. It is shown that these water soluble amino acid and dipeptide derivatives of fullerene (C60-AD) are quenchers of pyrene fluorescence and erythrosine phosphorescence of in both a water solution and liposomes. To study the permeability of the lipid bilayer a procedure based on the triplet probe technique has been developed. It has been found that the C60-AD derivatives under study are able to localize inside the artificial membrane, to penetrate into the liposomes through the lipid bilayer and to perform activated transmembrane transport of bivalent metal ions.

Comparative in vitro and in vivo study of a nitroxyl derivative of 5-fluorouracil (magnizil) on human gastrointestinal tumors.

AIMS AND BACKGROUND: There is much interest in nitroxyl derivatives of cytotoxic agents. We evaluated the potential activity of magnizil, a derivative of 5-fluorouracil, on human gastrointestinal tumors in 3 different in vitro and in vivo experimental models. METHODS: The activities of magnizil and 5-fluorouracil were comparatively determined in vitro on the HT29 cell line by a clonogenic assay and on tumor clinical specimens by an antimetabolic assay. The activity of both the drugs against human tumors was also assessed in mice with the subrenal capsule assay. RESULTS: A similar cytotoxic activity was found for magnizil and 5-fluorouracil on the HT29 cell line. As regards human tumors, a lower activity was observed for the nitroxyl derivative than for 5-fluorouracil, with response rates of 25% and 50%, respectively, at comparable concentrations. Moreover, among the tumors transplanted in the subrenal capsule of mice, two were sensitive to magnizil and 3 to 5-fluorouracil. CONCLUSIONS: Even though experimental results on human tumors indicate a somewhat lower activity for magnizil than the parent compound, its low toxicity and the possibility to clinically use high doses suggest the opportunity to further investigate the potential of this new anticancer agent on larger series of colorectal cancers in experimental systems.