DNA-damaging effects of dental bleaching agents.

We studied DNA-damaging effects of dental bleaching systems containing hydrogen peroxide and/or carbamide peroxide by the "comet assay" (alkaline version). Dental bleaching systems in a hydrogen peroxide concentration range from 0.03 to 30 mM produced a genotoxic effect on isolated HeLa cells in vitro comparable with the effects of pharmacopoeial hydrogen peroxide or urea peroxide. Catalase protected the cells against products containing hydrogen peroxide and had no effect on the genotoxicity of samples containing carbamide peroxide.

Dihydroquercetin (taxifolin) and other flavonoids as inhibitors of free radical formation at key stages of apoptosis.

Formation of free radicals in mitochondria plays a key role in the development of apoptosis, which includes formation of superoxide by the respiratory chain, formation of radicals by cytochrome c-cardiolipin complex in the presence of hydrogen peroxide or lipids, and chain lipid peroxidation resulting in cytochrome c release from mitochondria and initiation of the apoptotic cascade. In this work the effect of taxifolin (dihydroquercetin) and some other antioxidants on these three radical-producing reactions was studied. Peroxidase activity of the complex of cytochrome c with dioleyl cardiolipin estimated by chemiluminescence with luminol decreased by 50% with quercetin, taxifolin, rutin, Trolox, and ionol at concentrations 0.7, 0.7, 0.8, 3, and 10 microM, respectively. The lipid radical production detected by coumarin C-525-activated chemiluminescence decreased under the action of rutin and taxifolin in a dose-dependent manner, so that a 50% inhibition of chemiluminescence was observed at the antioxidant concentrations of 3.7 and 10 microM, respectively. Thus, these two radical-producing reactions responsible for apoptosis onset are inhibited by antioxidants at rather low concentrations. Experiments performed on liver slices and mash showed that taxifolin, quercetin, naringenin, and Trolox have low inhibitory effect on the lucigenin-dependent chemiluminescence in the tissue only at concentrations higher than 100 microM.

Blood testosterone in rats: correlation of the level of individual anxiety and its impairment after "death threat".

Studies of identical groups of male Wistar rats after preliminary selection to give groups including extreme behavioral types with low and high rankings on the anxiety scale showed that blood testosterone concentrations in intact rats (controls) correlated negatively with anxiety ranking, i.e., minimal hormone concentrations (no greater than 5 nM) corresponded to high levels of anxiety - with a predominance of passive defensive behavioral components on testing. Short-term exposure to a "death threat" situation (sight of a boa attacking and eating two individuals from the group of rats) impaired this correlational relationship in a manner comparable to the sequelae of chronic neuroticization by unavoidable pain stimulation. Impairments were manifest as scatter in measures in low-anxiety animals (3-21 nM). This characteristic, reflecting the multitude of adaptive pathways in the population in threat situations, distinguishes this type of action from neuroticization by unavoidable pain stimulation, which leveled out individual differences and decreased the hormone level.

[Blood testosterone in rats: correlation with individual anxiety and its derangement after the "death threat"].

After preliminary testing on a multiparameter scale, test and experimental groups of Wistar male rats were formed on the principle of identical distribution of individuals with different anxiety levels. A negative Spearman correlation between the testosterone blood concentration and the level of anxiety was observed in intact rats: the minimum hormonal concentrations (lower than 5 nmol/l) were found in rats with high anxiety, whereas the maximum concentrations (up to 16 nmol/l) corresponded to the higher anxiety level (prevalence of passive defense reactions during testing). After a sort-term exposure to life-threatening situation (viewing of a boa's attacking and devouring two victim rats from the test group), the correlation was deranged because of appearance of a scatter in testosterone blood concentration (from 3 to 21 nmol/l) in rats with low anxiety. Neurotization with inescapable pain stimulation also deranged the initial anxiety-testosterone correlation, but, as distinct from the exposure to life-threatening situation, eliminated individual differences in testosterone concentration at its low level. The results suggest the existence of multiple ways of adaptation to life-threatening situations in a rat population.

[Biologically active substances in grated cocoa and cocoa butter].

In the article results of comparative analysis of grated cocoa and cocoa butter samples are presented. The investigation was done by modern instrumental methods such as HPLC, GC, UV- VIS-spectroscopy, and also with application of titrimetric and grarimetric methods. In the analyzed samples contents of total phenolics changes in an interval 1,0-3,2%, including monomeric proantocyanidins 0,6-1,35%; pyrroloquinoline quinine (PQQ) 0,34-0,76 microg/g; phenyl ethylamine from 2,79 to 14,97 microg/g, tyramine from 9,56 to 71,68 microg/g, dopamine from 5,3 to 25,85 microg/g; theobromine from 3,3 to 8%, caffeine from 0,49 to 0,70%; among the amino acids at the greatest quantities were presented glutaminic and asparaginic acids, arginin and leucin; three main fatty acids were determined - palmitinic (31+/-2% rel.), oleinic (35+/-2% rel.) and stearinic (35+/-2% rel.); the main phytosterins were sytosterin (up to 192 mg%) and obtusifoliol (up to 198,5 mg%).

[Generation of negative air ions by wheat seedlings in a high voltage electrization of soil]. / Generatsiia otritsatel'nykh aéroionov prorostkami pshenitsy pri vysokovol'tnoi élektrizatsii pochvy.

It was shown that plantlets of wheat (Triticum vulgare) are capable of generating negative aeroions during the electrization of soil by high-voltage impulses. Soil electrization was carried out either from the moment of planting of seeds or from the appearance of the first seedlings. The concentration of negative ions was measured in the air at a distance of 50 cm from plants. In both variants, similar growth-related changes in the concentration of negative ions were observed. The generation of negative ions began on day 6 after the planting of seeds and reached a concentration of 380 x 10(3) ion/cm3. During the next three days, this level remained unchanged. On day 10, the generation of negative aeroions increased abruptly; on days 10-14, it was twofold as high as on days 7-9. The level of generation of negative aeroions by plants stimulated from the moment of appearance of plantlets was 5-8% higher than by plants stimulated from the moment of planting. The intensity of generation of negative aeroions upon additional illumination and in full darkness remained unchanged.

[Pharmacologic correction of the adverse effects of beta-adrenoblockaders on the kidneys in patients with hypertension]. / Medikamentoznaia korrektsiia otritsatel'nogo vliianiia beta-adrenoblokatorov na pochki u bol'nykh gipertonicheskoi bolezn'iu.

Determination of the slow isoenzymes of carbon esterases (SICE) in the urine by the disc-electrophoresis techniques was used as a marker of kidney impairment in 90 patients with II stage essential hypertension. In obsidan and visken treatment the frequency of SICE detection in the urine has increased from 30-50 to 70-100 per cent; the effective renal blood flow was reduced and specific peripheral resistance was increased and leg blood flow deteriorated. Subsequent administration of trental. phentolamine and corinfar alleviated the unfavourable effect of beta-adrenoblockers, enhanced renal blood flow, decreased the frequency of SICE detection to the initial level and improved the results of treatment.

[Treatment procedures in the vasoconstrictive form of hypertension using calcium antagonists in relation to their effect on kidney function]. / Taktika lecheniia vazokonstriktornoi formy gipertonicheskoi bolezni antagonistami kal'tsiia v zavisimosti ot ikh vliiania na sostoianie pochek.

Single sublingual administration of nifedipine at a dose of 20 mg to patients with essential hypertension (EH) with subsequent hemodynamic observation every hour for 4 h resulted in the reduction of systolic and diastolic arterial pressure (AP) by 10-15%, arteriolar tone (AT) by 30-40%. Renal metabolism was assessed by the presence of slow isoenzymes of carbonic esterases in urine. They were absent in healthy persons; before nifedipine administration they were detected in 62% of cases, after it--in 22%. Regular administration of nifedipine (30-60 mg/day) and verapamil (160-240 mg/day) in a less severe course of EH (AT less than 4500 conv. units) improved the renal blood flow decreasing AT and AP. Severe EH (AT greater than 4500 conv. units) was characterized by cases of inadequate action of the drugs: dramatic reduction of ERF was followed by a rise of AT and AP which could be accounted for by excessive vasodilation at the 1st stage with further development of the renal steal syndrome and a rise of AP and AT. In such cases lower doses of nifedipine, the combination of verapamil with hydrochlorthiazide and verapamil with prazosin hydrochloride were more effective; the combination of nifedipine with propranolol did not prevent a negative effect on the kidneys and was ineffective in high AT.

[Kidney function and the effectiveness of hypotensive therapy of patients with hypertension]. / Sostoianie pochek i éffektivnost' gipotenzivnoi terapii bol'nykh gipertonicheskoi bolezn'iu.

Ischemic renal lesion in 108 patients with hypertension was diagnosed by means of the determination of slow isoenzymes of carbonic esterases (CE5-7) in the urine. Their detection was a poor prognostic sign for any therapeutic method, particularly with the use of propranolol deteriorating renal circulation. The use of drugs not deteriorating or improving the renal blood flow (dopegyt, chlophelin, reserpine, apressin, corinfar, isoptin) brought about more promising results in such cases.

Pattern of blood circulation in the brain during rest and functional tests by Salyut-4 space crewmen.

Changes in the rheoencephalogram (REG) obtained for cosmonauts on the first and second expeditions during their time aboard the orbiting station, Salyut-4, are described. REGs were recorded by a small apparatus, Levkoi-3, with subsequent transmittal of the information to Earth stations. It was established that during flight under conditions of negative pressure on the lower half of the body (NPLHB), there was a decrease, in all cases, in pulse filling of brain blood vessels and an improvement in venous outflow from the cranial cavity. This indicates the efficiency of the compensation-adaptation reaction of the system studied to the state of weightlessness and the positive effect of prophylactic measures taken during flight. REG changes in indices affected by negative pressure were mainly such as were observed in preflight investigations, but there were individual differences. It was discovered that in all cosmonauts during performance of functional tests on a veloergometer, there was a significant increase in indices of pulse filling of brain blood vessels in response to muscle load in comparison with preflight studies. Normalization of basic REG indices took 3-7 min after the work was concluded. Planimetric analysis with REGs registered under conditions of long flight disclosed a variety of reactions of different sections of the vascular channels in the brain. Data obtained indicated the value of the REG method for making observations on crew members of space ships during orbital flights.