[Features of adhesion of anaerobic periodontopathogenic bacteria and Candida albicans fungi to experimental samples of basis dental plastic depending on surface roughness and polishing method].

AIM: Study the main surface parameters of milled polyacrylic materials using atomic force microscopy and primary microbial adhesion of periodontopathogenic group bacteria and Candida albicans fungi taking into consideration the method of sample polishing. MATERIALS AND METHODS: Studied samples: mill-treated without polishing (control); ergobox polished; polished in dental laboratory conditions; polished by a rubber brush in dentists' office. Microbial strains belonging to periodontopathogenic species (clinical isolates) that had been isolated from periodontal pockets of periodontitis patients: Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sanguis, C. albicans fungi were used for modelling experiments of primary adhesion of microbes to the material samples. RESULTS: S. sanguis had the highest degree of adhesion to polymer after milling, P. gingivalis, C. albicans--medium, F. nucleatum--low. A significant reduction of adhesion is observed during polishing in dental laboratory conditions or ergobox, less significant--during polishing in dental office. CONCLUSION: The data obtained allow to make a conclusion that the samples from polymer materials for preparation of prosthesis basis have varying degree of intensity of microbial adhesion of members of periodontopathogenic microflora and C. albicans fungi that depends on the polishing method, that accordingly determined the differences in colonization resistance against formation of microbial biofilm during polymer use in clinical conditions. . ,

[Biofilm formation on temporary dentures: correlation of primary adhesion, coaggregation and colonization].

Forty-six patients (20 male and 26 female, age 45-76) with temporary dental prosthesis were followed-up both clinically and microbiologically. The results of quantitative and qualitative assessment proved biofilm formed on acrylic resin to be potentially more aggressive because of high incidence and significant number of virulent germs as well as yeast-like Candida fungal. Laboratory polished polyurethane samples showed much lower colonization by virulent germs and Candida fungal. After biofilm stabilization PCR revealed twice-fold less incidence of virulent germs on polyurethane when compared to other tested materials.

Consequences of group fission for the patterns of relatedness among rhesus macaques.

When mammalian social groups exceed their optimal size, they often tend to split. In view of the potential evolutionary benefits, it should be more advantageous for animals to stay with kin, rather than nonkin, during such fission events. In the present study, the spontaneous fission of two social groups, R and S, of rhesus macaques living on Cayo Santiago, Puerto Rico, provided the opportunity to compare the kinship structure of the corresponding parent and daughter groups, using information on both maternal and paternal relatedness. In both instances, maternal half-siblings and pairs of animals from the same family were significantly more prevalent in the fission products than in the parent group. During the split of group R, significantly more paternal half-siblings stayed in the remnants of the parent group than joined the seceding group. Our findings are compatible with previous behavioural studies demonstrating that female primates bias their social behaviour more to maternal than to paternal kin, but that both types of half-siblings prefer each other more than unrelated animals. It remains to be clarified by future research, however, whether the observed co-segregation of paternal half-sibs in our study reflects active choice or is a by-product of the group-specific kin structures, prior to fission.

[Participation of the inhibitory mechanisms in the gastric hypersecretion caused by overproduction of glucocorticoids]. / Ob uchastii tormoznykh mekhanizmov v gipersekretsii zheludka, vysvannoi izbytkom gliukokortikosteroidov.

Semichronic experiments on rats with gastric fistula discovered that subcutaneous glucocorticoid prednisolone attenuates adrenergic (adrenalin) and M-cholinoreceptor (gastrocepin) inhibition of basal gastric secretion. This enhances the secretion in the course of the inhibitory process.

[Effect of prednisolone on the inhibition of basal gastric secretion in laboratory rats induced by fats or blockade of H2-receptors]. / Vliianie prednizolona na tormozhenie bazal'noi zheludochnoi sekretsii laboratornykh krys, vyzyvaemoe zhirom ili blokadoi H2-retseptorov.

Experiments on rats with gastric fistulae for the first time have shown that glucocorticosteroid prednisolone causes weakening of the fat and H2-receptor inhibition of basal gastric secretion.

[Microbiological validation of the choice of basic plastic for removable dentures]. / Mikrobiologicheskoe obosnovanie vybora bazisnoi plastmassy s"emnykh zubnykh protezov.

Adhesion of obligate and facultative anaerobic bacteria, favoring the development of oral inflammatory diseases, including the cariesogenic and periodontogenic bacteria and Candida albicans fungi, isolated from patients with periodontitis, to 13 basic materials used in removable denture making, was studied. The adhesion of all bacteria (Streptococcus sanguis, Prevotella melangogenica, Fusobacterium nucleatum, Corynebacterium xerosis) and fungi to hot polymerization basic materials was the maximum. The most perspective basic plastic for clinical use (preserving intact oral microbiocenosis and preventing stomatitis induced by denture wearing) are cold polymerization materials, such as Redont-03, Dentoplast Breden, Leocryl, and UHF polymerization materials Acron GC, AKR-MV, and Etakril-02.

Kink nucleation in the two-dimensional Frenkel-Kontorova model.

A computer simulation of thermofluctuation nucleation of kinks on dislocations and their dynamics is carried out in the framework of the two-dimensional Frenkel-Kontorova model. It is shown that at relatively low temperatures and applied stresses the kinks can appear as a result of developing instability of phonon modes localized in the vicinity of the dislocation. The transition from this mechanism to the ordinary thermofluctuation kink nucleation with temperature increase can reveal itself in the peculiarities of yield stress temperature dependence.

[Clinical and laboratory studies of bacterial adhesion to validate the choice of material for making provisional dentures for patients with periodontal diseases]. / Vybor konsruktsionnogo materiala dlia izgotovleniia vremennykh zubnykh protezov litsam s bolezniami parodonta na osnovanii klinicheskikh i laboratornykh issledovanii bakterial'noi adgezii.

Adhesion of bacteria favoring the development of oral inflammations, including cariesogenic and periodontopathogenic (Actinobacillus actinomycetemcommitans, Streptococcus sanguis, Fusobacterium nucleatum, Staphylococcus warneri) and yeast fungi (Candida albicans), to 13 materials used for making provisional dentures was studied. Adhesion of all the studied bacteria and fungi to Russian material Esterfil Foto was the minimum. Clinical use of this material in patients with chronic generalized periodontitis showed that it was well tolerated and the treatment led to improvement of oral microbiocenosis.

[Effect of prednisolone on the basal gastric secretion in laboratory rats depending on functional state of the stomach adrenoreceptors]. / Vliianie prednizolona na bazal'nuiu zheludochnuiu sekretsiiu laboratornykh krys v zavisimosti ot funktsional'nogo sostoianiia adrenoretseptorov zheludka.

Activation of the stomach adrenoreceptors with adrenaline resulting in inhibition of fundal glands promotes stimulating effect of prednisolone glucocorticosteroid action on basal gastric secretion.

Increased reproductive success of MHC class II heterozygous males among free-ranging rhesus macaques.

Gene conversion and balancing selection have been invoked to explain the ubiquitous diversity of the antigen-presenting proteins encoded in the vertebrate major histocompatibility complex (MHC). In the present study, direct evidence for over-dominant selection promoting MHC diversity in primates is provided by the observation that, in a large free-ranging population of rhesus macaques, males heterozygous at MHC class II locus Mamu-DQB1 sired significantly more offspring than homozygotes (the male-specific selection coefficient s equals 0.34). This heterozygote advantage appeared to be independent of the actual male Mamu-DQB1 genotype. No similar effect emerged for a captive group of monkeys of similar genetic background but under veterinary care.

Natal dispersal in rhesus macaques is related to serotonin transporter gene promoter variation.

A VNTR polymorphism previously characterized in the promoter region of the human serotonin transporter (SLC6A4) gene was also found to segregate two major alleles (l and s) among the free-ranging rhesus macaques of Cayo Santiago, Puerto Rico. When VNTR genotypes were related to age at male natal dispersal on Cayo Santiago, ss homozygotes (43 of 532 males tested) were found to have left their natal groups significantly earlier (age 57.1 +/- 2.6 months) than carriers of the l allele (ll age, 71.5 +/- 2.1 months; ls age, 63.5 +/- 1.5 months; P = 0.0001). Since migration implies reproductive costs and benefits that change with age at dispersal, migration at an intermediate age might have conferred a heterozygote advantage serving to maintain the VNTR polymorphism via overdominant selection.

DNA sequence polymorphisms in genes involved in the regulation of dopamine and serotonin metabolism in rhesus macaques.

A systematic search was performed for DNA sequence variation in genes regulating neurotransmitter metabolism in rhesus macaque (Macaca mulatta). These genes included dopamine and serotonin receptors and transporters, and tyrosine hydroxylase. A total of 13 single nucleotide polymorphisms in five different genes were identified, namely: DRD1 (-244T->G), q = 0.45; DRD1 (-179C->T), q = 0.19; DRD1 (-127G->A), q = 0.25; DRD1(-11T->G), q = 0.08; DRD1(-81C->T), q = 0.19; DRD3 (248G->A), q= 0.08; DRD3(341G->C), q = 0.11; DRD3(377A->G), q = 0.19; DRD3 (403C->T; A59V), q= 0.11; DRD4(2608G->A), q= 0.48; HTR1D(-506G->T), q = 0.47; HTR1D(-173C->T), q = 0.47; and HTT(340G->A), q = 0.39. The nucleotide positions listed correspond to the human homologs.

[Effect of prednisolone on the gastric juice basal secretion during blockade of M-cholinoreceptors by gastrozepin in rats]. / Vliianie prednizolona na bazal'nuiu sekretsiiu zheludochnogo soka v usloviiakh blokady M-kholinoretseptorov gastrotseptinom u krys.

A moderate depression of the stomach M-cholinic receptors was found to facilitate the prednisolone glucocorticoid stimulating effect on basal gastric secretion.

[Effect of resection of the proximal part of the small intestine on inhibition of gastric secretion as affected by pituitrin, gastrozepin and histodil]. / Vliianie rezektsii proksimal'noi chasti tonkoi kishki na tormozhenie zheludochnoi sekretsii, vyzyvaemoe pituitrinom, gastrotsepinom i gistodilom.

Semichronic experiments on rats with gastric fistula have revealed that the resection of the proximal third of the small intestine results in impairments of the gastric secretion inhibition induced by gastrozepin or histodil blockade of M-choline- and H2-receptors. At the same time the operation has no noticeable impact on the gastric secretion inhibition caused by pituitrin (vasopressin) on V1-receptors. The difference found is accounted for by a relative specialization of the enterogastric influences that regulate the sensitivity of gastric secretory mechanisms to inhibitory signals.

[The participation of the small intestine in the inhibition of gastric secretion induced by H2-receptor blockade]. / Uchastie tonkoi kishki v tormozhenii zheludochnoi sekretsii, vyzyvaemom blokadoi H2-retseptorov.

Resection of the proximal portion of small intestine impaired the inhibition of spontaneous gastric secretion induced by the hystodile H2-receptors blockade in rats. The data obtained suggests participation of enteral mechanisms in the inhibition of gastric secretion.

[The effect of resection of the proximal small intestine on the inhibition of gastric secretion induced by gastrotsepin]. / Vliianie rezektsii proksimal'noi chasti tonkoi kishki na tormozhenie zheludochnoi sekretsii, vyzyvaemoe gastrotsepinom.

The removal of the proximal 1/3 part of the intestine led to reduction of "spontaneous" inhibition of gastric secretion caused by gastrocepin provoking selective blockade of gastric M-cholinoreceptors in rats with gastric fistulae. The enteral mechanisms regulating gastric secretion, seem to participate in this inhibition and gastric M-cholinoreceptors seem to change their function under the influence of enterogastric activity.