[Densitometric investigation of the dynamics of bone defects regeneration in surgical treatment of chronic periodontitis].

Apicotomy of 105 teeth of 78 patients with chronic periodontitis has been performed. The periapical defect were filled with two kinds of osteoplastic matter: the first group was treated with demineralised bone matrix of newborn pigs (DBMNP), the second group with artificial hydroxyapatite, while both matters were enriched with platelet rich plazma (PRP).As a third, control group, cases. The defects of which were not filled with osteoplastic matter, were investigated. The dynamics of the regeneration of bone defects was studied based on the data of densitometric investigation. The results of objective observations have revealed high efficiency of surgical treatment of chronic periodontitis with the filling with DBMNP in combination with PRP.

[Role of glycolysis and antioxidant enzymes in the toxicity of amyloid beta peptide Abeta25-35 to erythrocytes].

The role of glycolysis and antioxidant enzymes in amyloid beta peptide Abeta(25-35) toxicity to human and rat erythrocytes was studied. The erythrotoxicity of Abeta(25-35) was shown to increase two- to fourfold both in the absence of glucose in the incubation medium and upon the addition of sodium fluoride, an enolase inhibitor. Potassium cyanide, a Cu,Zn-superoxide dismutase inhibitor, abolishes the toxic effect of Abeta(25-35) to erythrocytes, whereas mercaptosuccinate, a glutathione peroxidase inhibitor, and ouabain, a Na+,K+-ATPase inhibitor, promote it. Sodium azide, a catalase inhibitor, did not affect the cell lysis under the action of Abeta(25-35) . The results support the hypothesis that H2O2, Cu,Zn superoxide dismutase, and glutathione peroxidase are involved in the toxicity mechanism rather than superoxide radical. Glycolysis and Na+,K+-ATPase play a substantial protective role. Fullerene C(60) nanoparticles are toxic to erythrocytes of both types; their toxicity is not related to enhanced oxidative stress and the mechanism of toxicity differs from that of Abeta(25-35) .

[On the occasion of the 20th anniversary of the accident on the Chernobyl NPP: medical consequences in Armenia].

The aim of this work is the analysis of the indices of the health and of the structure of the sicknesses of the inhabitants of Armenia who took part in the liquidation of the consequences of the Chernobyl accident. Also it is the determination of possible dependence of the frequency of diseases for the most widespread classes of sicknesses on the received dose of the irradiation, according to the data of the clinical examination and dispensarysation; and also it is the revelation of the role of other factors influenced on the health indexes.

[Antioxidant enzymes of the rat liver, brain, heart and erythrocytes in ammonia intoxication].

Injection of large amounts of ammonium salts leads to rapid death of animals. However, the molecular mechanisms involved in ammonia toxicity remain to be clarified. We have tested the effect of toxic dose of ammonium acetate on the activities of antioxidant enzymes in rat liver, brain, heart and erythrocytes. Acute ammonia intoxication resulted in rapid (within 11 min) decrease in superoxide dismutase, catalase and glutathione peroxidase activities in liver and brain mitochondria and cytosol and in erythrocytes, but in increase of these enzyme activities in heart. Diminished activities of the antioxidant enzymes in liver, brain and erythrocytes suggest that the systemic oxidative stress takes place, whereas their elevated activities in heart can be the adaptive reaction to oxidative stress in hyperammoniemia.

[The estimation of the state of endogenous intoxication in the development of experimental bile peritonitis].

The indices of endogenous intoxication were investigated in 45 dogs. It was shown that the development of 24-hour bile peritonitis was accompanied by pronounced endogenous intoxication with injured cell membrane structure and impaired activity of NO-synthases.

[Circulating immune complexes in ischemic and hemorrhagic strokes]. / Tsirkuliruiushchie immunnye kompleksy pri ishemicheskom i gemorragicheskom insul'takh.

The study aimed at determination of circulating immune complexes (CIC) levels in a serum of patients with ischemic and hemorrhagic strokes, isolation of the complexes and their antigen composition identification. Spectrophotometric assay, polyethylene glycol precipitation and SDS PAG electrophoresis were used. Comparing to controls, significantly elevated levels of both small and big CIC were detected in the serum of the patients with ischemic stroke, while in the patients with hemorrhage stroke only the level of small CIC was elevated. The antigen CIC composition was specific for each stroke form and for control group either. Being compared to literature data, the results obtained revealed a specificity of the antigen CIC composition in ischemic and hemorrhagic strokes.

[Genetic determination of the neurophysiological mechanisms of the cortico-subcortical integration of bioelectrical activity of the brain]. / Geneticheskaia obuslovlennost' neirofiziologicheskikh mekhanizmov korkovo-podkorkovoi integratsii bioélektricheskoi aktivnosti mozga.

Contribution of genetical factors to neurophysiological mechanisms of cortico-subcortical integration was investigated in 12 pairs of the monozygotic and 5 pairs of dizygotic twins (aged from 18 to 25). In each pair of twins as well as in all 544 unrelated pairs of subjects from both groups, interpairs similarity of the character of the spatial interaction of bioelectrical activity of the neocortex for different combinations of statistical correlations of EEG (from 16 monopolar electrodes) was estimated. The data obtained allow to suggest a higher common population invariance and a relatively small hereditary and phenotypic variability of morphofunctional systems, which underlie neurophysiological mechanisms of the brain integration in general. Apparently, the formation of the brain stem and subcortical regulatory structures in the ontogenesis, the structures that play the main role in the realization of system combination of different parts of the brain into united formation, occurs to all individuals according to a single principle since its disturbance can probably affect the fundamental monomorphal features of the species. In turn, one can expect a great interindividual variability of establishing of the intraregional connections of neocortex, the role of genetic and environmental factors in the formation of short and relatively long interactions being complex.

[Effect of the external electrostatic field on the conformation of a macromolecule containing charged groups]. / Vliianie vneshnego élektrostaticheskogo polia na konformatsiiu makromolekuly, soderzhashchei zariazhennye gruppy.

A method for calculating the free energy of a macromolecule containing charged groups in electrostatic field in aqueous solution was proposed. The non-electrostatic component of free energy was calculated with consideration of van der Waals interactions between uncharged parts of the macromolecule. The electrostatic component of free energy was calculated with regard for the interactions of charged groups of the macromolecule with each other and with water molecules. It was found that, depending on the strength of external electric field, the free energy of the system passes through a minimum, whereas the internal energy passes through a maximum. By minimizing the free energy, relative changes in the mean radius 'r' and the distance between the termini of the macromolecule 'h' were calculated. It was found that, at some values of field strength, both 'r' and 'h' decrease. An increase in strength led to an increase in 'r' and 'h'. The regularities observed depend on the charge of the macromolecule and the spatial redistribution of macromolecules and counterions.

Clastogenic factors in the plasma of Chernobyl accident recovery workers: anticlastogenic effect of Ginkgo biloba extract.

Clastogenic factors are found in the plasma of persons irradiated accidentally or therapeutically. They persisted in the plasma of A-bomb survivors over 30 years. Clastogenic factors were found in 33 of 47 Chernobyl accident recovery workers (often referred to as liquidators) in a previous study (I. Emerit et al., J. Cancer Res. Clin. Oncol. 120, 558-561, 1994). In the present study, we show that there is a positive correlation between clastogenic activity and dose and that these biomarkers of oxidative stress can be influenced successfully by appropriate antioxidant treatment. With the authorization of the Armenian Ministry of Health, 30 workers were treated with antioxidants from Ginkgo biloba leaves. The extract EGb 761 containing flavonoids and terpenoids was given at a daily dose of 3 x 40 mg (Tanakan, IPSEN, France) during 2 months. The clastogenic activity of the plasma was reduced to control levels on the first day after the end of the treatment. A 1-year follow-up showed that the benefit of the treatment persisted for at least 7 months. One-third of the workers again had clastogenic factors after 1 year, demonstrating that the process which produced clastogenic factors continued. However, the observation that antioxidants do not have to be given continuously is encouraging for intervention trials on a large-scale basis. These appear justified, since clastogenic factors are thought to be risk factors for the development of late effects of irradiation.

[Effect of ucrinol on lipid metabolism in liver tissue]. / Vliianie ukrinola na lipidnyi metabolizm v tkani pecheni.

Alterations in content of phospholipids as well as dynamics of lipid free-radical oxidation were studied in the hepatocytes of the rats poisoned with various doses of the toxic agent ucrinol within 1.3 and 6 months. Low concentrations of the toxin (1.5 mg/kg) did not cause any detectable alterations of the patterns studied. However, higher concentrations of ucrinol (15-150 mg/kg) produced markedly pronounced destructions which were dose- and time-dependent.

[Prostaglandin D2-synthase from cattle brain: purification and physico-chemical properties]. / Prostaglandin D2-sintaza iz mozga byka: ochistka i fiziko-khimicheskie svoistva.

Prostaglandin D2-synthase has been purified from bovine brain for the first time and characterized. The enzyme has a molecular mass of 21 kDa and a pH optimum at 9.0 and is activated by dithiothreitol. The presence in the enzyme molecule of carbohydrates and lipids has been established and a preliminary conclusion made about the qualitative composition of the lipids. The ability of the enzyme to form aggregates under the influence of the detergent has been demonstrated. The role of the lipid component in the preservation of the enzyme monomeric structure as well as the possible mechanisms of action of the above inhibitors and activators are discussed.

Transferable clastogenic activity in plasma from persons exposed as salvage personnel of the Chernobyl reactor.

Clastogenic factors were first described in the plasma of people who had been accidentally or therapeutically irradiated. They were found also in A-bomb survivors, where they persisted for many years after the irradiation. The present study searched for these factors in the plasma of 32 civil workers from Armenia, who had been engaged as "liquidators" around the Chernobyl atomic power station in 1986. It also included 15 liquidators who had emigrated from the ex-Soviet Union to Israel. Reference plasma samples were obtained from 41 blood donors from the Armenian Blood Center in Yerevan. The samples were tested for their clastogenic activity in blood cultures from healthy donors. The majority of results from the liquidators exceeded those from the unexposed reference samples. The samples from the first Armenian group, with the higher average irradiation dose (0.6 +/- 0.6 Gy), were more clastogenic than those from the second group exposed to 0.2 +/- 0.2 Gy. The number of aberrations in the test cultures was 17.9 +/- 2.9% and 10.5 +/- 3.8% respectively, compared to 5.7 +/- 3.2% in the cultures exposed to the reference ultrafiltrates from Armenian blood donors. The samples from the Israeli liquidators also induced significantly increased aberration rates (14.0 +/- 3.9% aberrant cells). The clastogenic activity was regularly inhibited by superoxide dismutase, indicating that the chromosome-damaging effects of radiation-induced clastogenic factors are exerted via the intermediation of superoxide radicals, as is known for clastogenic factors of different origin.

[The role of phospholipids and their fatty acids in the structural organization of membranes of plasmid-containing and plasmid-less Salmonella derby cells]. / Rol' fosfolipidov i ikh zhirnykh kislot v strukturnoi organizatsii membran plazmidosoderzhashchikh i besplazmidnykh kletok Salmonella derby.

The effect of R-plasmid on the qualitative and quantitative compositions of phospholipids and their fatty acids in bacterial (S. derby) cells has been studied. It has been found that the lack of R-plasmid in bacterial cells leads to a sharp decrease in the phospholipid content, in the phosphatidylcholine content in particular, and causes an increase in the per cent content of lysophosphatidylcholines. The per cent content of saturated and nonsaturated fatty acids of phospholipids in plasmid-free cells does not change appreciably. In the plasmid-free strain of S. derby the intensity of lipid peroxidation is associated with a relatively high content of alpha-tocopherol.