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Levin, George G. "Women and the Second Estate in 16th Century Zambezia: Gendered Powers, a 'Puppet' African Queen and Succession in vaKaranga Society, 1500-1700." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1106.
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Women in vaKaranga society of the 15th to 17th centuries have been portrayed as oppressed by an "extremely patriarchal" system, but the reality, while still fitting the simple classification of a 'patriarchal' monarchy, indicates quite a bit more negotiation of gendered powers than women, as a class, experienced in the Mediterranean or East Asia. The vaKaranga were the architects of Great Zimbabwe, the capital of a growing state, colonizing their cousins of the Zambezi river, which their Kusi-Mashariki Bantu forefathers had traversed southward a millennium before. Civil war had (apparently) split one nation into two states, Mutapa (Monomotapa) and Khami (Torwa, Toroa, Changamire) immediately before Portuguese ships arrived at Sofala in 1502. Statements like "women are dust, one does not count dust" have been used to illustrate the traditional social outlook of the Shona, descendants of the vaKaranga and a major population in present-day Zimbabwe, Zambia, Malawi and central Moçambique. However, close reading of early Portuguese-language sources on women in vaKaranga society suggests that, prior to influence from these original European colonists, vaKaranga women negotiated everyday and political power in a near-even exchange with men, predicated on the imbalance of power women held in the metaphysical dimension, their control of industries from gold production to staple crop production and a strategy for minimizing economic risk for a king transacting a brideprice or 'rovora' exchange. In this, vaKaranga women are exceptions to the theory that societies must become more gender imbalanced as they begin to form classes and state-level monarchies.
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Shankar, Suraj Kunnath Spilman Richard. "The Mutawa killers and other stories." Diss., A link to full text of this thesis in SOAR, 2007. http://soar.wichita.edu/dspace/handle/10057/1172.
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Muchakwana, Thomasina. "Evaluating the effect of conservation agriculture basin tillage system on household food security in Mutasa." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/d1015054.
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The research was done with the aim of evaluating the effect of the basin tillage system as a method of conservation agriculture, on improving smallholder farmers’ food security in Mutasa, Manicaland Province in Zimbabwe. This research focussed on the 2010/2011 agricultural season. The main objectives of this study were to determine the contribution of CA basin tillage system on increasing yields per hectare, to evaluate which CA principles are being practiced by smallholder farmers, and to determine how many months the harvested maize will last. The study compares smallholder farmers who practiced CA with farmers who practiced other tillage methods. The other tillage methods are ploughing and conventional hand hoe tillage systems. On average the farmers who practiced CA used 0.47 hectares of land whilst farmers who practiced other tillage methods used an average of 0.43 hectares of land. The average amount of maize produced by smallholder farmers who practiced CA was 824 kg while who practiced other tillage methods produced an average of 498 kg. Farmers practicing CA produced yield with an average of 1175 kg/ha of maize grain while farmers who practiced other tillage methods produced an average of 946 kg/ha. Food security in this reaseach was measured by the amount of months the maize grain produced was lasting in relation with the household size. 57 percent of the farmers who practiced CA are food secure because they have maize grain to last them a full consumption year and moreover surplus. Only 27 percent of the farmers who practiced other tillage methods produced enough to last a full consumption year.
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Grutzpalk, Jonas. "Mutawa : eine islamische Polizei in Saudi‐Arabien." Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2009/1707/.
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Larsson, Jakob. "Verkstaden för potentiell keramik : Eadem Mutata Resurgo." Thesis, Konstfack, Keramik & Glas, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-6349.
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Nita, Ana-Silvia. "Genetic mapping and molecular characterization of tbr1 mutant in Arabidopsis thaliana." Phd thesis, [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=977653145.
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Thevenot, Tracy Lynn. "Aspects of sugar transport via the phosphoenolpyruvate sugar phosphotransferase system of streptococcus mutans /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq23673.pdf.
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Monteiro-Oliveira, Marcela Pinto 1982. "Estudo da ação antimicrobiana da terapia fotodinamica sobre lesões de carie produzidas in vitro na dentina de dentes bovinos." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288089.
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Previous issue date: 2010<br>Resumo: Durante o processo conhecido como terapia fotodinâmica, a aplicação de fotossensibilizadores associados a uma fonte de luz de comprimento de onda complementar, gera produtos que podem danificar componentes essenciais das células, e causar a morte celular. Dentro desse contexto, a aplicação dessa terapia sobre microrganismos presentes em lesões de cárie é de grande valia, uma vez que poderá reduzir a quantidade de tecido dental a ser removido no tratamento da cárie, diminuir as chances de progressão da doença bem como os riscos de acometimento pulpar do elemento dentário. Assim, o objetivo deste estudo in vitro foi determinar parâmetros para o uso de um diodo emissor de luz (LED) associado ao corante azul de orto toluidina (TBO) na redução da contagem de Streptococcus mutans presentes em lesões de cárie dentinária. Para isto, 72 espécimes de dentina coronária de dentes bovinos foram imersos em cultura contendo Streptococcus mutans para produzir lesões de cárie. Tais espécimes foram divididos aleatoriamente em 6 grupos (n=12): Controle (exposição a NaCl a 0,9% por 5 min); TBO (exposição ao TBO a 0,01% por 5 min); LEDA (exposição ao LED por 4,2 min); LEDB (exposição ao LED por 6,5 min); PDTA (exposição ao corante associado ao LED por 4,2 min) e PDTB (exposição ao corante associado ao LED por 6,5 min). As densidades de energia utilizadas para os tempos de 4,2 e 6,5 min, foram de 166 e 249 J/cm2, respectivamente. Antes e após os tratamentos, amostras de tecido dentinário cariado foram coletadas e analisadas microbiologicamente, por meio da contagem das unidades formadoras de colônia (UFC) de S. mutans. A profundidade das lesões de cárie produzidas pelo modelo microbiológico utilizado foi determinada por meio da microscopia de luz polarizada. Foram utilizados os testes ANOVA/Tukey para comparar os valores de log redução dos grupos (a=5%). Observou-se redução significativa de S. mutans nos grupos em que aplicou-se TBO associado ao LED, com as duas densidades de energia utilizadas. Entretanto, nenhuma diferença significativa foi encontrada para os diferentes tempos de irradiação. Concluiu-se que os parâmetros utilizados no presente estudo, para o emprego do LED associado ao TBO, foram efetivos em reduzir a contagem de S. mutans presentes em lesões de cárie dentinária.<br>Abstract: Photodynamic therapy (PDT) is a technique that consists in the activation of certain photosensitizers by light in the presence of tissue oxygen, resulting in the production of reactive radicals capable of inducing cell death. In this context, this therapy may become a suitable approach to disinfect the dentin tissue during the caries treatment, and reduce the tissue removal, minimizing the probability of caries progression and pulp involvement. This randomized in vitro study determined parameters for using a light-emitting diode (LED) with toluidine blue O (TBO) for reduction of Streptococcus mutans counts inside dentin caries. Seventy two bovine coronary dentin slabs were immersed in Streptococcus mutans culture for demineralization production. Dentin slabs were allocated to 6 groups (n=12) as follows: Control (treated with 0.9% NaCl solution for 5 min); TBO (treated with 0.1 mg/ml TBO for 5 min); LEDA (submitted to irradiation for 4.2 min); LEDB (submitted to irradiation for 6.5 min); PDTA (treated with TBO plus irradiation for 4.2 min) and PDTB (treated with TBO plus irradiation for 6.5 min). The energy densities used for 4.2 and 6.5 min correspond at 166 and 249 J/cm2, respectively. Before and after treatments, dentin samples were analyzed with regard to S. mutans counts. The caries lesion depth produced by the microbiological model was analyzed by polarized light microscopy. ANOVA/Tukey tests were utilized to compare log reductions among groups (a=5%). Bacterial reduction was observed when dentin was exposed to both TBO and LED at both irradiation times. However, no difference in S. mutans reduction was found between the two energy densities. Concluding, although the use of LED combined with TBO was effective in reducing the Streptococcus mutans counts in carious dentin, this effect may not have clinical significance.<br>Mestrado<br>Odontopediatria<br>Mestre em Odontologia
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Vizoto, Natália Leal 1982. "Avaliação da função biológica do sistema de dois componentes SptRS de Streptococcus mutans." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288675.
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Previous issue date: 2015<br>Resumo: Streptococcus mutans é uma espécie bacteriana comum da microbiota bucal de seres humanos envolvida na patogênese da cárie dentária e em endocardites infecciosas promovidas por bacteremias de origem bucal. Para ser transmitido e ocupar seus nichos ecológicos, S. mutans precisa persistir na saliva e se adaptar fisiologicamente a cada fase da colonização, um processo que provavelmente envolve diversas alterações do seu transcriptoma. Para isto, S. mutans utiliza sistemas reguladores de transcrição de dois componentes (SDC). O SDC SptRS foi identificado através de análises in silico do genoma da cepa S. mutans UA159, como ortólogo do sistema SptSR (Spt de Saliva persistence) de Streptococcus pyogenes. O objetivo deste trabalho foi investigar a participação do sistema SptRS de S. mutans em fenótipos importantes para a colonização bucal. Para isto, mutantes knockout dos genes sptR e sptS, SMU.927 e SMU.928 respectivamente, foram construídos a partir da cepa UA159 (UAsptR- e UAsptS-) e comparados com a cepa parental em análises de morfologia, crescimento planctônico sob diferentes condições nutricionais, persistência em saliva humana, formação de biofilme e autólise a 44oC. Além disto, genes do regulon de SptRS foram pesquisados através de ensaios da Imunoprecipitacão de Cromatina seguido de sequenciamento (ChIP-seq), RT-PCR quantitativo (RT-PCRq) e de Ensaios de Retardamento da Mobilidade Eletroforética (EMSA) com proteína recombinante SptRr de S. mutans. Os mutantes sptR e sptS mostraram crescimento planctônico lento em meios de cultura RPMI e em MQD comparados à cepa parental, além de atividade autolítica reduzida em 22,4 e 53,13%, respectivamente. Não foram observadas, entretanto, alterações significativas na morfogênese, formação de biofilmes in vitro, nem na persistência em saliva humana. Os dados de ChIP-seq e RT-qPCR indicaram que SptRS regula genes envolvidos na resposta de estringência (SMU.926), repressão catabólica (ccpA), metabolismo de múltiplos açúcares (SMU.78, SMU.137, SMU.542, SMU.1734), sistemas fosfoenolpiruvato-fosfotransferase (PTS) (SMU.2047, SMU.114, SMU.115) sistemas de transporte do tipo ABC (SMU.182, SMU.880, SMU.905, SMU.1035, SMU.1095, SMU.1178c, SMU.1939) e biogênese de parede celular (SMU.1091, SMU.2147, SMU.609, SMU.1434c, SMU.22). SptR funcionou como um regulador negativo em 86% (37/43) dos genes testados. Análises de RT-qPCR e EMSA indicaram ainda que SptR regula diretamente o regulador de transcrição CovR (SMU.1924), envolvido na repressão de genes de virulência e formação de biofilmes. Este estudo fornece evidências de que SptRS regula diversas funções de S. mutans importantes para a sobrevivência em condições nutricionalmente escassos, aparentemente coordenando o metabolismo com o crescimento bacteriano e com a expressão de genes de virulência<br>Abstract: Streptococcus mutans is a common bacterial species of the bucal microbiota of humans involved in the pathogenesis of dental caries and infectious endocarditis promoted by bacteremia of bucal origin. To be transmitted and occupy their ecological niches, S. mutans need to persist in saliva and adapt physiologically to each phase of colonization, a process that probably involves several changes in its transcriptome. To this end, S. mutans uses transcriptional regulatory systems called Two Component System (TCS). The TCS SptRS was identified in an in silico analysis of the genome of S. mutans strain UA159, as an orthologue of the SptRS system (Spt of Saliva persistence) of Streptococcus pyogenes. The aim of this study was to investigate the role of the TCS SptRS in functional traits important for S. mutans to colonize its bucal niches. Thus, knockout mutants of sptR and sptS (SMU.927 and SMU.928, respectively) were obtained in strain UA159 (UAsptR-, UAsptS-) and compared to parental strain regarding morphology, planktonic growth under different nutritional conditions and persistence in human saliva, biofilm formation and autolysis at 44oC. In addition, genes of SptRS regulon were analised by Chromatin Immunoprecipitation followed the sequencing (ChIP-seq), quantitative RT-PCR (RT- qPCR) and Electrophoretic Mobility Shift Assays (EMSA) with S. mutans SptR recombinant protein. Inactivation of sptR/S promotes slow planktonic growth in RPMI and CDM, culture media 22.4 to 53.13% reductions in autolysis respectively, but does not significantly affect morphogenesis. However, mutants do not show significant alterations in biofilm formation or in persistence in human saliva. ChIP-seq and RT-qPCR analyses showed that SptRS regulates genes for stringent response (SMU.926), metabolism of multiple sugars (SMU.78, SMU.137, SMU.542, SMU.1734), catabolite repression (SMU.1591, ccpA), phosphoenolpyruvate phosphotransferase systems (PTS), ABC transport systems (SMU.182, SMU.880, SMU.905, SMU.1035, SMU.1095, SMU.1178c, SMU.1939) and cell wall biogenesis (SMU.22, SMU.609, SMU.1091, SMU.1434c, SMU.2147) SptR worked as a negative regulator of 86% (37/43) of the tested genes. RT-qPCR and EMSA analyses further showed that SptR directly represses expression of the transcriptional regulator CovR (SMU.1924), which is a repressor of genes involved in biofilm formation and virulence. This study provides evidence that SptRS regulates several functions important for S. mutans survival under poor nutritional conditions, apparently coordinating metabolism with bacterial growth and expression of virulence genes<br>Doutorado<br>Microbiologia e Imunologia<br>Doutora em Biologia Buco-Dental
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Murwira, Epifania. "Contract farming in Zimbabwe : the Mutasa garlic project." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/95627.
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Thesis (MBA)--Stellenbosch University, 2012.<br>Contract farming is being given renewed attention on the African continent in the wake of reduced public expenditure for credit programmes. Many African countries have recognised the potential of contract farming in linking farmers to viable markets and stimulating agricultural production in the face of globalisation.
In Zimbabwe prior to 1998, smallholder farmers were poorly integrated in the cash economy and had extremely low incomes, largely due to poor access to productivity-enhancing inputs. Small-scale farmers were marginalised as the economy focused on the larger commercial farms. Currently, mainstream banks have been unable to provide funding due to their own capital inadequacy and the view that smallholder farming is a risky and unprofitable sector. There is also a shift in roles as the government moves from direct participation in agricultural production and marketing towards facilitation, legislation and enforcement. The private sector is now participating more actively in the agricultural sector, providing credit to smallholder farmers.
This research seeks to better understand the partnership between private and public sector players in Zimbabwe’s agricultural credit programmes, through a study of Leo Marketing and the Zimbabwe Agricultural Market Development initiative called the Agricultural Input Supply Programme (AISP). In this research, the Mutasa Garlic Project, implemented by the AISP, has been analysed to achieve the objective. One hundred smallholder farmers have been contracted to commercially produce garlic in the Mutasa district. Using a sample of 20 farmers, the study examined how this financing model contributes to improved access to productivity-enhancing inputs, viable markets and technical expertise for the farmers.
The analysis indicates that farmers have access to inputs but the model still needs improvement in distributing them efficiently to ensure that all farmers have their inputs in time for the planting season. Marketing and extension services in the project are operating well. The study reveals that there is potential for growth in the number of farmers contracted to the programme. As the contracting model continues to improve, the same model can be used for similar projects in surrounding districts.
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Tu, Shang-Min. "Probing the mechanism of 2-methyleneglutarate mutase and glutamate mutase." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515095.
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Galvão, Lívia Câmara de Carvalho 1985. "Avaliação da atividade antimicrobiana de óleos essenciais contra microrganismos do grupo mutans e determinação da atividade antiproliferativa." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288527.
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Previous issue date: 2012<br>Resumo: O objetivo desse trabalho foi avaliar a atividade antimicrobiana, in vitro, de óleos essenciais e frações dos óleos de melhor atividade, contra microrganismos do grupo mutans em estado planctônico. Além disso, os biofilmes de Streptococcus mutans foram submetidos às frações ativas e os óleos de melhor atividade e frações ativas foram avaliados quanto à sua citotoxicidade e caracterizados quimicamente. Para isso, vinte óleos essenciais (OE) foram obtidos por hidrodestilação a partir de plantas pertencentes ao banco de germoplasmas da Coleção de Plantas Medicinais e Aromáticas (CPMA/CPQBA/UNICAMP). Estes OE foram avaliados quanto à sua atividade antimicrobiana por meio dos ensaios: concentrações inibitória (CIM) e bactericida mínima (CBM) contra Streptococcus mutans UA159. Controles positivo (clorexidina 0,12 %) e negativo (propilenoglicol 6,12 % e 25 %) também foram testados...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital<br>Abstract: The aim of this study was to evaluate the in vitro antimicrobial activity of essential oils (EO) and fractions from highest activity EO against planktonic cells of mutans streptococci. Besides, the biofilms formed by this microorganism were submitted to active fractions and the higher activity EO and active fractions were evaluated regarding their citotoxicity and chemically characterized. For this, twenty essentinal oils were obtained from plants of the "Collectio of Medicinal and Aromatic Plants" (CPMA, CPQBA/UNICAMP), germplasm bank by hydrodistillation. These EO were evaluated by antimicrobial assays: minimum inhibitory (MIC) and bactericidal (MBC) concentrations against Streptococcus mutans UA159. Positive (chlorhexidine 0.12%) and negative (propylene glycol 6.12 % and 25%) controls were also tested...Note: The complete abstract is available with the full electronic document<br>Mestrado<br>Farmacologia, Anestesiologia e Terapeutica<br>Mestre em Odontologia
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Carneiro, Haline de Lima. "Avaliação de propriedades de superfície da liga Ti-35Nb-7Zr-5Ta submetida à anodização e seus efeitos n adesão bacteriana /." Araraquara, 2014. http://hdl.handle.net/11449/110821.
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Orientador: Luís Geraldo Vaz<br>Co-orientador: Laiza Maria Grassi Fais<br>Banca: Valfrido Antonio Pereira Filho<br>Banca: Valentim Adelino Ricardo Barão<br>Resumo: Este estudo comparou as propriedades de superfície e a adesão Streptococcus mutans na liga Ti-35Nb-7Zr-5Ta e no titânio comercialmente puro (Ti cp) antes e após a anodização. Foram utilizados discos (Ø8mmx2mm; N = 40) divididos em 2 grupos: T (Ti cp), TNZT (Ti-35Nb- 7Zr-5Ta), e subdivididos conforme a realização (A+) ou não (A-, controle) da anodização eletroquímica (300 V, 1 min) em β-glicerofostato de sódio + acetato de cálcio. As propriedades avaliadas foram: topografia de superfície e identificação qualitativa dos elementos químicos (microscópio eletrônico de varredura-MEV/EDS), energia livre de superfície (ELS, mensurada em goniômetro) e rugosidade média (Ra, determinada em rugosímetro). Para avaliação da adesão bacteriana, os discos foram contaminados com Streptococcus mutans (NTCC 25175) para determinação de UFC/mL e do padrão de adesão (MEV). Os valores de Ra e ELS de cada grupo foram comparados (A- vs. A+) por meio do teste Kruskal-Wallis associado ao teste de Dun (α = 0,05). Os valores de Ra (μm) e ELS (mN/m), respectivamente, foram: A-- T=0,97/44,24; TNZT=0,17/36,68; A+ - T=1,21/56,88; TNZT=0,53/53,64, com aumento significante de ambas propriedades (p < 0,05) após a anodização. A análise em MEV/EDS indicou a formação de uma camada multiporosa, com deposição de íons Ca e P nos subgrupos A+. Após a anodização houve aumento na adesão do patógeno apenas na liga TNZT. Conclui-se que a anodização do Ti cp e da liga TNZT alteram as propriedades de superfície com potencial para melhorias na osseointegração, contudo há aumento na adesão de S. mutans na liga TNZT.<br>Abstract: The aim of this study was to compare the surface properties and the adhesion of Streptococcus mutans on Ti-35Nb-7Zr-5Ta and commercially pure titanium (cp Ti) before and after the anodization. Discs (Ø8mmx2mm, N=40) were divided into 2 groups: T (cp Ti), TNZT (Ti-35Nb-7Zr- 5Ta), and subdivided in untreated (A- , control) or anodic treated (A+) in β- glicerofostato + calcium acetate (300 V, 1min). The evaluated surface properties were: surface topography and qualitative identification of chemical elements (in scanning electron microscope -SEM/EDS), surface free energy (SFE, measured with a goniometer), and the average roughness (Radetermined in profimoleter). The discs were contaminated with Streptococcus mutans (NTCC 25175) for determination of CFU/mL; the surfaces with adhered viable cell were also analyzed with SEM. The values of Ra and ELS were compared (A- vs . A+) by means of Kruskal-Wallis associated Dun test (α= 0.05). The median Ra (μm) and ELS (mN/m), respectively, were: A- T=0.97/44.24; TNZT=0.17/36.68; A+ T=1.21/56.88; TNZT=0.53/ 53.64. All groups showed significantly higher values of Ra and ELS (p < 0.05) after anodizing. The analysis in SEM/EDS indicated the formation of a multiporous layer with deposition of Ca and P ions. Only anodic treated TNZT exhibited an increase in adhesion of S. mutans. It was concluded that the anodic tretament of Ti cp and TNZT change the surface properties with potential improvements for osseointegration, despite the increase in the adhesion of S. mutans on TNZT.<br>Mestre
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Workman, Eileen. "Characterization of Mutant SMN and Development of Mutant SMN Transgenic Mice." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1237823559.
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Zinyengere, David Takudzwa. "Household Determinants of Malaria in Mutasa District of Zimbabwe." ScholarWorks, 2018. https://scholarworks.waldenu.edu/dissertations/5597.
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Malaria is a vector borne, acute febrile illness, caused by Plasmodium parasites. Malaria impacts the medical and socioeconomic development programs of affected communities, as it diverts both individual and national resources into managing the disease burden. The purpose of this study was to explore and evaluate household determinants of malaria in Mutasa District, Zimbabwe. The precede-proceed theoretical model guided the study. Secondary data from Demographic Health Survey and District Health Management Information System, and current data from household determinant questionnaires, were used to evaluate the influence and significance of identified household determinants. Multiple logistic regression models were used to examine the association between malaria prevalence and the identified household determinant factors. The study result showed the existence of household determinant factors that affected the prevalence of malaria in Mutasa District. The presence of livestock animals within a 50-meter radius of the household, ownership of animal drawn carts and low socioeconomic status significantly increased malaria risk, while availability of drinking water within a 50-meter radius of the household, significantly reduced malaria risk. Other variables, although not statistically significant, had varied levels of malaria infection risk. The study results may contribute to positive social change by providing an insight into innovative strategies that enhance existing interventions. The study results may also provide opportunities for upgrading malaria intervention policies and sustainable community participation, thus enhancing malaria elimination efforts
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Nguyen, Nhung Phuong. "Axial Ligand Mutant: H229A." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/honors_theses/1.
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Many pathogenic bacteria use their iron acquisition mechanisms to live inside hosts. Streptococcus pyogenes is a pathogenic bacterium that uses streptococcal iron acquisition ABC transporter to obtain heme. SiaA (HtsA, spy1795), a lipoprotein located on the cell surface, serves as a heme binding protein. To understand the iron-uptake mechanism, histidine 229, one of the two proposed axial ligands in SiaA, was mutated to alanine. SiaA H229A was expressed in E. coli, lysed by French Press, and purified by fast protein liquid chromatography (FPLC). SDS-PAGE indicated that pure protein was isolated. Nickel affinity FPLC gave purer H229A when 0.5 M imidazole was added to the binding buffer. Overall, histidine 229 is likely to be an axial ligand in wild type SiaA, as shown by the fact the mutant readily lost heme as evidenced by UV-vis spectra.
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Nguyen, Nhung Phuong. "Axial ligand mutant H229A /." unrestricted, 2007. http://etd.gsu.edu/theses/available/etd-08082008-134926/.
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Thesis (honors)--Georgia State University, 2007.<br>Title from file title page. Under the direction of Dabney White Dixon. Electronic text (88 p. : col. ill.) : digital, PDF file. Description based on contents viewed Sept. 30, 2008. Includes bibliographical references (p. 46-47).
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Branting, Christina. "Studies on S̲t̲r̲e̲p̲t̲o̲c̲o̲c̲c̲u̲s̲ m̲u̲t̲a̲n̲s̲ glucans with special reference to cell adhesion." Stockholm : Kongl. Carolinska Medico Chirurgiska Institutet, 1988. http://catalog.hathitrust.org/api/volumes/oclc/18171129.html.
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Lindquist, Birgitta. "Mutans streptococci in human dentition some factors influencing colonization and distribution /." Göteborg : University of Göteborg, 1991. http://catalog.hathitrust.org/api/volumes/oclc/25383720.html.
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Almeida, Luciana Salles Branco de. "Atividade antimicrobiana dos extratos da Rheedia brasiliensis e potencial anticarie do seu composto bioativo." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288507.
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Orientador: Pedro Luiz Rosalen<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-10T06:14:10Z (GMT). No. of bitstreams: 1
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Previous issue date: 2008<br>Resumo: Este estudo avaliou a atividade antimicrobiana de extratos da Rheedia brasiliensis contra
Streptococcus mutans e o potencial anticárie do seu composto ativo isolado. Os extratos hexânicos (EH), acetato de etila e etanólico (concentrações entre 6,25-800 µg/ml) do fruto (¿bacupari¿) foram testados contra S. mutans UA159 por meio de determinação das concentrações inibitória mínima (CIM) e bactericida mínima (CBM). Biofilmes de 5 dias de formação foram tratados com os extratos ativos (100 x CIM), por 0, 1, 2, 3 e 4 h, e plaqueados para contagem das UFC/ml (time kill). Os extratos ativos foram submetidos à análise química por métodos espectroscópicos, e o composto ativo isolado (0,625-80 µg/ml) foi testado contra células de S. mutans por meio de CIM/CBM. A influência do composto isolado (12,5-100 µg/ml) sobre a síntese de glucanos foi avaliada através da atividade da enzima glucosiltranferase (GTF) B em superfície de hidroxiapatita. A ação do
composto sobre biofilmes (125 e 250 µg/ml) foi testada com os ensaios de queda de pH e inibição de formação de biofilme. O potencial anticárie do composto (250 µg/ml) foi avaliado em ratas Wistar sob alto desafio cariogênico. Os EH (casca e semente) inibiram S. mutans em baixas concentrações (CIM:12,5-25 µg/ml) e reduziram células viáveis dos biofilmes após 4 h de exposição. O composto ativo presente foi identificado como a 7- epiclusianona (7-epi), a qual inibiu o crescimento do S. mutans (CIM:1,25-2,5 µg/ml), a atividade da GTF B em superfície (48% de inibição) e a produção de ácidos do S. mutans em biofilme, porém não reduziu a formação e o acúmulo dos biofilmes. No estudo animal, a 7-epi reduziu a incidência e a severidade de cárie e a microbiota total, mas não diminuiu a porcentagem de S. mutans. A 7-epi diminuiu a virulência do S. mutans e inibiu o desenvolvimento de cárie in vivo, sugerindo ser um agente terapêutico promissor para o controle do biofilme dental cariogênico. Palavras-chave: Rheedia brasiliensis, 7-epiclusianona, Streptococccus mutans, fatores de virulência, cárie animal<br>Abstract: The present study evaluated the antimicrobial activity of Rheedia brasiliensis extracts against Streptococcus mutans and the anticaries properties of its isolated bioactive compound. Hexane (HE), ethyl-acetate and ethanolic extracts (concentrations ranging from 6.25 to 800 µg/ml) of R. brasiliensis fruits (¿bacupari¿) were tested against S. mutans UA159 by determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). S. mutans 5-days-old biofilms were treated with active
extracts (100 x MIC), for 0, 1, 2, 3 e 4 h (time-kill), and plated for colony counting (UFC/ml). Such extracts were submitted to exploratory chemical analyses to isolate and identify the bioactive compound using spectroscopic methods. The compound (0.625-80 µg/ml) was then tested against S. mutans cells using MIC/MBC assays. The influence of the bioactive compound (12.5-100 µg/ml) on glucans synthesis was evaluated by testing the
activity of glucosyltranferase (GTF) B on hydroxyapatite surface. The effects of the compound (125 e 250 µg/ml) on biofilms were analyzed using glycolytic pH-drop and inhibition of formation assays. The anticaries activity of such compound (250 µg/ml) was evaluated in Wistar rats submitted to a high cariogenic challenge. HE (peel and seeds) reduced S. mutans cells at low concentrations (MIC:12.5-25 µg/ml) and also biofilm viability after four hours, confirming the presence of the bioactive compound. This compound was identified as 7-epiclusianone (7-epi), which inhibited the S. mutans growth (MIC:1.25-2.5 µg/ml), the activity of GTF B (48% of inhibition) and the acid production, not interfering with the formation and accumulation of biofilms. In the animal study, 7-epi
additionally reduced the incidence and severity of caries and also the total microbiota, however no reduction on the percentage of S. mutans was observed. In conclusion, 7-epi may be considered a promising agent to control cariogenic dental biofilm. Keywords: Rheedia brasiliensis, 7-epiclusianone, Streptococccus mutans, virulence factors, animal caries<br>Mestrado<br>Farmacologia, Anestesiologia e Terapeutica<br>Mestre em Odontologia
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Ccahuana, Vasquez Renzo Alberto. "Desenvolvimento e validação de um modelo de crescimento de biofilmes de S. mutans e estudo do efeito da sacarose na expressão de gtfBCD e dexA em biofilmes dentais formados in vitro e in situ." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289274.
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Orientador: Jaime Aparecido Cury<br>Tese (doutorado) - Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-15T16:16:59Z (GMT). No. of bitstreams: 1
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Previous issue date: 2010<br>Resumo: Modelos in vitro e in situ tem sido desenvolvidos para o estudo do biofilme dental. Protocolos que simulem episódios de "fartura-miséria" quando açúcares da dieta estão presentes na cavidade bucal e permitam avaliação de cárie dental são necessários. Por outro lado, poucos estudos da expressão gênica de biofilmes formados in situ foram realizados. Assim, este trabalho teve como objetivos: Desenvolver e validar um modelo de formação de biofilme de S. mutans que simule episódios de "fartura-miséria" e permita avaliar mudanças no biofilme, e desmineralização do esmalte dental. Também, avaliar o efeito da sacarose na expressão de genes gtfB, gtfC, gtfD e dexA de biofilme dental formado in vitro e in situ. Para os primeros objetivos, biofilmes de S. mutans UA159 cresceram durante 5 dias sobre blocos de esmalte bovino a 37oC, 10% CO2, em meio de cultura ultrapurificado, sendo avaliado: o efeito de concentração (1 a 20%) de sacarose e da freqüência (0 a 8x/dia) de exposição à sacarose. O efeito da clorexidina (0, 012 a 0,12%) 2x/dia e de NaF 0,05% foram testados para validar o modelo. Foram determinadas: viabilidade bacteriana, acidogenicidade do biofilme, biomassa e polissacarídeos; e a desmineralização do esmalte. Para o último objetivo, no estudo in vitro biofilmes de S. mutans UA159 cresceram nas mesmas condições acima citadas e foram expostos à sacarose 1% constante (controle) ou sacarose 10% 8x/dia (grupo intermitente) e após 48, 72 e 120 h os biofilmes foram coletados para análise gênica de gtfB, gtfC, gtfD e dexA. No experimento in situ, um estudo cruzado de 2 fases experimentais de 7 dias foi realizado, com 9 voluntários que usaram um dispositivo palatino contendo 12 blocos de dentina que foram submetidos 8x/dia a soluções de sacarose de 1, 5, 10 e 20%. No final, os biofilmes foram coletados para análise microbiológica, bioquímica e de expressão gênica de gtfB, gtfC, gtfD e dexA. Os resultados de padronização mostraram que as concentrações de sacarose de 10% e 20% e a frequência 8x/dia provocam mudanças no biofilme e na demineralização similares ao controle. Clorexidina mostrou efeito dose resposta, diminuindo biomassa, viabilidade bacteriana, acidogenicidade do biofilme e demineralização do esmalte, NaF 0,05% não mostrou atividade antimicrobiana, mas apresentou similar efeito a clorexidina 0,12% na redução da desmineralização. Para o último objetivo, os resultados in vitro do grupo intermitente mostraram que a expressão de genes analisados parece ser constante enquanto que no controle a expressão desses genes incrementou-se em função ao tempo. No estudo in situ, o incremento da concentração de sacarose aumentou os valores de peso úmido do biofilme, lactobacilos e polissacarídeos extracelulares do biofilme. Quanto a expressão gênica, só foi possível quantificar o gtfB e não apresentou diferenças entre os grupos. Em conclusão, o modelo in vitro apresenta potencial para avaliar o efeito antimicrobiano de substâncias sobre biofilmes e desmineralização dental. A quantificação da expressão de genes gtfB, gtfC, gtfD e dexA foi possível in vitro, mas in situ somente a expressão de gtfB foi determinada e não parece ser regulada pela concentração de sacarose.<br>Abstract: In vitro and in situ models have been developed to study dental biofilms. Protocols, that simulate the alternations of "feast or famine" episodes that happen in oral environment in the presence of dietary carbohydrates and allowing dental caries evaluation, are necessaries. On the other hand, few studies about gene expression of dental biofilm formed in situ were performed. Thus, the objectives of this research were: To develop and to validate a model of S. mutans biofilm formation simulating 'feast-famine' episodes that allows biofilms and dental demineralization changes assessment. Also, to evaluate the effect of sucrose exposure on expression of gtfB, gtfC, gtfD and dexA of in vitro and in situ dental biofilms. For the first objectives, S. mutans UA159 biofilms were grown during 5 days on bovine enamel slabs at 37oC, 10% CO2 in ultra-purified culture media. To develop the model, the effect of sucrose concentration (1 - 20%) 8x/day and frequency (0 - 8x/day) exposure were evaluated and to validate the model, chlorhexidine (CHX) effect (0.012- 0.12%) 2x/day was tested. Bacterial viability, biofilm acidogenicity, biomass and polysaccharides were determined, and enamel demineralization was evaluated by surface hardness loss. To the last objective, for in vitro study, S. mutans UA159 biofilms were grown in the same conditions of previous experiments and were exposed to 1% sucrose constantly (control) or 10% sucrose 8x/day (intermittent group) and after 48, 72 and 120 h the biofilms were collected for analysis. For in situ experiment, a crossover study was conducted in two phases of 7 days each, with nine volunteers that wore intraoral palatal appliances containing 12 dental dentin slabs, which were extra orally submitted 8 times/day to sucrose solutions of 1%, 5%, 10% and 20% . On the 7th day, biofilms were collected for analysis. RNA from the in vitro and in situ biofilms were extracted and purified. Gene expression of gtfB, gtfC, gtfD and dexA were evaluated by real time PCR. In vitro development and validation results showed that 10% and 20% sucrose concentrations and frequency 8x/day provoked biofilm and enamel demineralization changes similar to control group. CHX showed dose-response effect decreasing biomass, bacterial viability and enamel demineralization (p<0.05). Also, 0.05% NaF did not show antimicrobial effect but had similar effect than 0.12% CHX decreasing enamel demineralization (p<0.05). With regard to gene expression of in vitro experiment, gene expression of intermittent group was constant along the time. In situ results showed that biofilm wet weight, lactobacillus, extracellular polysaccharides values of the biofilm increased according to the increase of sucrose exposure. No differences for gtfB gene expression between the groups were observed (p<0.05) and no levels of gtfC, gtfD and dexA were detected. In conclusion, the model developed and validated has potential to assess substances with antimicrobial effect on biofilm and dental demineralization. Quantification of gtfB, gtfC, gtfD and dexA gene expression levels were possible for S. mutans biofilms in vitro study but only gtfB gene expression of in situ study can be determined and was not regulated by sucrose concentration.<br>Doutorado<br>Cariologia<br>Doutor em Odontologia
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Cavichioli, Eder Augusto Mastropietro. "Fototerapia com luz azul combinada à aplicação de clorexidina 0,12% em um modelo ortodôntico com biofilme cariogênico /." Araraquara, 2020. http://hdl.handle.net/11449/192572.
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Orientador: Luiz Gonzaga Gandini Junior<br>Resumo: Aparelhos ortodônticos fixos criam áreas de estagnação para biofilmes dentários e dificultam a limpeza dos dentes; portanto, existe o risco de desenvolver lesões incipientes de cárie durante o tratamento ortodôntico. O objetivo deste estudo é verificar se a aplicação de luz azul antes da clorexidina 0,12% no esmalte, bráquete e elástico ortodôntico reduziria ou inibiria os biofilmes maduros de Streptococcus mutans e seu crescimento nesses substratos 24 horas após a aplicação dos tratamentos; e se esse tratamento interfere na adesão do bráquete ao esmalte. Biofilmes de S. mutans UA159 foram formados por 5 dias sobre amostras compostas por esmalte bovino, bráquete ortodôntico e elástico ortodôntico. Em seguida, as amostras foram tratadas com NaCl 0,89% por 1 minuto (NaCl), luz azul por 12 minutos (BL), clorexidina 0,12% por 1 minuto (CHX) e luz azul por 12 minutos seguido da aplicação de clorexidina 0,12% por 1 minuto (BL+CHX). O acúmulo de biofilme imediatamente após os tratamentos e 24 horas após os tratamentos foram avaliados por unidades formadoras de colônias (CFU) e peso seco (DW). O pH do meio foi medido no quinto dia e sexto dia. A formação de biofilme nas amostras após os tratamentos (Imediato) e no recrescimento (Regrowth) foi avaliada visualmente por microscopia confocal de varredura a laser (CLSM). O teste de adesão (SBS) entre o bráquete e o esmalte foi feito após as amostras serem termocicladas por 500 ciclos (5°C e 55°C), tratadas e termocicladas novamente nas me... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Fixed orthodontic appliances create areas of stagnation for dental biofilms and make it difficult to clean the teeth; therefore, there is a risk of developing incipient lesions of caries during the orthodontic treatment. The objective of this study is to verify if the application of blue light prior to 0.12% chlorhexidine (CHX) on enamel, orthodontic brackets and elastics would reduce or inhibit mature Streptococcus mutans biofilms and their regrowth on these substrates 24 h after the application of the treatment; and if this treatment would interfere with bracket adhesion to the enamel. Biofilms of S. mutans UA159 were formed for 5-days over samples composed by a bovine enamel, an orthodontic bracket and an orthodontic elastic. Then, the samples were treated with 0.89% NaCl for 1 minute (NaCl), blue light for 12 minutes (BL), 0.12% chlorhexidine for 1 minute (CHX) and BL for 12 min + 0.12% CHX for 1 min (BL+CHX). Biofilm accumulation immediately after treatments and 24-h after treatments (regrowth) were evaluated by colonies forming units (CFU) and dry weight (DW). The pH of the spent media was measured on the 5th and 6th day. Biofilm formation on the samples after the treatments and on the regrowth was visually evaluated by confocal laser scanning microscopy (CLSM). Shear bond strength (SBS) between bracket and enamel was evaluated after specimens were thermocycled for 500 cycles (5° and 55 °C), treated and thermocycled again in the same conditions. Shear forces (N/mm2 ) we... (Complete abstract click electronic access below)<br>Mestre
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Tournelle, Kimura Pamela Madeleine. "Prevalencia y diversidad de bacterias pertenecientes al género Streptococcus en saliva de niños pre-escolares chilenos entre 2 y 5 años de edad con y sin caries." Tesis, Universidad de Chile, 2013. http://www.repositorio.uchile.cl/handle/2250/117563.
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Trabajo de Investigación Requisito para optar al Título de Cirujano Dentista<br>Introducción: La cavidad oral es un ecosistema mixto, formado por diversas
especies microbianas, en donde las bacterias cumplen un rol fundamental en el
equilibrio salud- enfermedad. Se ha descrito a la caries dental como una de las
patologías orales más prevalentes a nivel mundial y se ha observado que especies
pertenecientes al género Streptococcus, específicamente al grupo viridans, están
fuertemente relacionadas con su desarrollo. S. mutans ha sido una de las
especies más asociadas a su inicio y progresión. Sin embargo, esta enfermedad
puede ocurrir en ausencia de él y, otras especies pertenecientes a este género,
podrían tener una inesperada relevancia en la enfermedad.
Objetivo: Determinar la prevalencia y diversidad de especies bacterianas
pertenecientes al género Streptococcus en saliva de niños pre-escolares chilenos
con y sin caries.
Metodología: Muestras de saliva total no estimulada fueron colectadas de la
cavidad oral de niños pre-escolares chilenos, entre 2 y 5 años de edad, que
presentan caries (10 individuos) o libres de caries (10 individuos), según índice
ICDAS II. Se determinó la capacidad tamponante y pH salival, recuento,
aislamiento e identificación bacteriana pertenecientes al género Streptococcus. La
identificación se realizó mediante test bioquímicos, Reacción en Cadena de la
Polimerasa (PCR) y secuenciación de ADN, según corresponda.
Resultados: Se observaron diferencias en relación a las especies identificadas en
las muestras de sujetos con y sin caries. De los aislados obtenidos de sujetos sin
caries, las especies más prevalentes fueron S. salivarius (40%), S. mutans (20%)
y S. thermophilus (13,3%) y las especies aisladas en baja proporción
correspondieron a S. vestibularis y S. sanguinis (3,3% cada una). De los aislados
obtenidos de sujetos con caries, la especie más prevalente correspondió a S.
salivarius (73,3%) y las especies encontradas en menor proporción
correspondieron a Bacillus subtilis subsp. subtilis (16,7%), S. anginosus y S. mitis
(3,3% cada una). Los análisis estadísticos para asociar las variables edad, pH,
capacidad tamponante y recuento bacteriano, en relación a prevalencia de caries,
resultaron ser no significativos.
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Conclusiones: Las especies del género Streptococcus y otras especies
identificadas, tanto para sujetos con y sin caries, fueron diferentes en cuanto a
diversidad. Sin embargo, especies que han sido identificadas como autores
principales tanto del desarrollo de caries como de su ausencia, fueron encontradas
en baja proporción o no fueron encontradas en este grupo etario. S. salivarius
resultó ser la especie aislada con mayor frecuencia en ambos grupos y,
parámetros como edad, pH, capacidad tamponante en relación con prevalencia de
caries, no fueron significativos. Esto podría revelar que las propiedades
cariogénicas y de virulencia de cada especie estarían en íntima relación con las
condiciones ambientales y las asociaciones bacterianas que ellas realicen dentro
del Biofilm, que una misma especie podría actuar tanto a favor o en contra del
hospedero y que un mayor tamaño muestral sería necesario para obtener
resultados más concluyentes.
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Ribeiro, Thyciana Rodrigues. "A study of salivary peptide profile in children with early childhood caries: envisioning saliva as a diagnostic tool." Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=3576.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico<br>The aim of the present study was to find a relation between salivary peptides, caries experience and mutans streptococci (MS) levels in saliva of caries free (CF) and caries susceptible (CS) children in early childhood. One hundred and six 10 â 71 month-old children participated in the study. Fifty-eight children were CF and 48 who had experienced dental caries formed the CS group. Two samples of whole saliva were collected from all participants. Unstimulated whole saliva was collected, subsequently centrifuged. Supernatants were lyophilized, divided into two pools (CF and CS) and individual samples, and stored at -20oC for posterior analysis using LC-MS (Liquid Chromatography Mass Spectrometry) to study the peptide profile. Identification of salivary peptides was based on theoretical molecular masses available from online databases. Stimulated whole saliva was collected and used for MS detection in MSB agar medium. MS concentration in saliva was reported in cfu/mL. Dental examination was performed and dmfs/dmft scores were calculated. Data was analysed by using logistic regression. The chromatograms from CF and CS pools of saliva had different peak patterns. The identification of molecular masses suggested the presence of 9 peptides. Three of them were significantly related with caries experience. The presence of HNP-3 (α-defensin 3) (p = 0.019) and HBD-3 (β-defensin 3) (p = 0.034) reduced the chances of experiencing early childhood caries (ECC). The presence of PRP IB-4 significantly increased caries experience (p = 0.035). In addition, age (p = 0.020) and MS counts (p = 0.036) increased caries experience, however gender was not associated with dental caries (p = 0.877). Our results suggest that presence of specific peptides in saliva of CF or CS children in early childhood predisposes to a higher or lower risk of caries experience.<br>Este trabalho buscou estudar o perfil de peptÃdeos salivares de crianÃas com cÃrie da primeira infÃncia, relacionando-o com nÃveis de estreptococos do grupo mutans (EGM) salivares e experiÃncia de cÃrie. Cento e seis crianÃas, na faixa etÃria de 10 a 71 meses de idade, participaram do estudo, sendo 48 com experiÃncia de cÃrie e 58 sem cÃrie da primeira infÃncia. Duas amostras de saliva total foram coletadas de todos os participantes. A primeira amostra era composta de saliva nÃo estimulada, utilizada para anÃlise dos peptÃdeos. ApÃs coletada, essa saliva foi centrifugada, o sobrenadante retirado, liofilizado, dividido em pools com cÃrie, sem cÃrie e em amostras individuais e armazenado em freezer a -20oC atà anÃlise em aparelho de LC-MS (Cromatografia LÃquida acoplado ao EspectrÃmetro de Massa). A busca por peptÃdeos foi baseada em massas conhecidas de peptÃdeos existentes em bancos de dados. Saliva estimulada representou a segunda coleta, utilizada para o cultivo dos EGM (UFC/mL) em meio Ãgar mitis salivarius bacitracina (MSB). Anamnese e exame dentÃrio foram realizados para cÃlculo do Ãndice ceo-s e ceo-d. Os dados foram analisados por meio de modelo logÃstico binÃrio. Resultados foram considerados significantes quando p-valor < 0,05. Os cromatogramas obtidos a partir dos pools de crianÃas com/sem cÃrie apresentaram diferenÃas em relaÃÃo aos picos apresentados. A identificaÃÃo das massas moleculares sugeriram a presenÃa de nove peptÃdeos. RegressÃo logÃstica mostrou que 3 peptÃdeos se relacionaram com experiÃncia de cÃrie. PRP IB-4 associou-se a um aumento de experiÃncia de cÃrie (p=0,035); α-defensina 3 (p=0,019) e β-defensina 3 (p=0,034) associaram-se à reduÃÃo de experiÃncia de cÃrie. Em adiÃÃo, aumento na idade (p=0,020) e aumento na contagem de EGM (p=0,036) ocasionaram um aumento na experiÃncia de cÃrie, mas sexo nÃo se relacionou com cÃrie dentÃria (p=0,877). A partir desses resultados, pÃde-se concluir que a presenÃa de peptÃdeos especÃficos na saliva de crianÃas com e sem cÃrie dentÃria predispÃem a um maior ou menor risco à essa doenÃa.
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Costa, Ana Rosa 1977. "Estudo in vitro do efeito da clorexidina e do etanol na dentina em diferentes condições do substrato dentinário e tempos de armazenagem : Study in vitro the effect of chlorhexidine and ethanol on dentin in different conditions of the dentin substrate and storage times." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288584.
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Orientador: Regina Maria Puppin Rontani<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-10-05T18:49:21Z (GMT). No. of bitstreams: 1
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Previous issue date: 2013<br>Resumo: O propósito deste estudo foi avaliar a influencia de diferentes tipos de substrato (Capitulo 1) e tratamento com etanol 100% (Capitulo 2) ou digluconato de clorexidina a 2% (CHX) (Capitulo 3) na resistência e longevidade da união compósito/dentina, apos diferentes períodos de armazenagem. Os dentes humanos hígidos foram divididos em 3 grupos, de acordo com o substrato dentinario: (Sd) dentina hígida, (Ci) dentina infectada (manutenção da carie) e (Ca) dentina afetada (remoção parcial de carie). As superfícies oclusais de terceiros molares hígidos foram removidas com disco diamantado dupla face sob refrigeração, a fim de expor a superfície plana dentinaria hígida, a qual foi submetida ao desenvolvimento da lesão de carie artificial com S. mutans. Brocas esféricas foram usadas para remover parcialmente o tecido cariado pigmentado, ate que permanecesse apenas a dentina levemente corada (Ca). Em seguida, os dentes foram novamente subdivididos, de acordo com o tratamento da superfície: Grupo Controle (Ct) - nenhum tratamento (Capitulo 1); Ct e (Et) - aplicação de etanol 100% (Capitulo 2); e, Ct e (CHX) - aplicação de digluconato de clorexidina a 2% (Capitulo 3). O substrato foi condicionado com acido fosfórico a 35% por 15 s, lavado por 30 s e seco com leve jato de ar. CHX ou Et foram aplicados apos o condicionamento acido. O sistema adesivo Adper Single Bond 2 (3M ESPE) foi aplicado de acordo com as recomendações do fabricante e fotoativado por 20 s com a fonte de aparelho de luz XL 2500. Sobre a superfície de união foram inseridos incrementos de 2 mm do compósito Z350 (3M ESPE), polimerizados usando a fonte de luz XL 2500 por 40 s, ate confeccionar um bloco com 6 mm de altura. As amostras foram armazenadas em água destilada a 37o C por 24 horas. Apos, os dentes foram seccionados perpendicularmente a área de união, de modo a obter palitos com área de secção transversal de 1mm2. Os palitos foram armazenadas em três períodos: 24 horas, 6 meses e 1 ano. Em seguida, as amostras foram submetidas ao ensaio de resistência de união a microtração usando a maquina de ensaio EZ test (EZS, Shimadzu) a velocidade de 0,5 mm/minuto. Os dados foram submetidos a Analise de Variância e ao teste de Tukey HSD (?=0,05). A união em Sd mostrou valores de resistência de união significativamente maior quando comparado a Ca e Ci. As amostras armazenadas nos períodos de 6 meses e 1 ano resultou na diminuição da resistência de união, independente do tipo de substrato e/ou tratamento. O etanol não foi efetivo em melhorar a resistência de união para os três substratos de dentina avaliados. A clorexidina não influenciou na resistência de união nos períodos de armazenagem avaliados, independente dos substratos<br>Abstract: The aim of this study was to evaluate the effect of 2% chlorhexidine digluconate (CHX) and 100% ethanol wet-bonding (Et) on the degradation of the adhesive system bond strength in sound or artificial caries-affected/infected dentin after different storage times under microtensile test (_TBS). The sound teeth were divided into 3 groups, according to dentin substrates: sound dentin, caries-infected dentin (maintained of caries) and caries-affected dentin (partial removal of caries). Non-carious human third molars had their occlusal enamel removed with a slow speed diamond saw, under copious water-cooling to expose a flat-surfaced sound dentin, which was submitted to the microbiological challenge (S. mutans) for the development of artificial caries. Spherical drill was used to remove soft pigmented carious tissue till hard and slightly pigmented dentin remains (Ca). After, the teeth will be assigned into 3 subgroups according to surface treatment: water wet- bonding (Ct) (Chapter 1); Ct and 100% ethanol application (Et) (Chapter 2); and, Ct and chlorhexidine digluconate 2% application (CHX) (Chapter 3). The substrate will was etched with 35% phosphoric acid gel for 15 s, rinsed for 30 s with tap water and dried with oil/water-free air. The CHX or Et was applied for 60 s, just after etching with 35% phosphoric acid gel. The adhesive system Adper Single Bond 2 (3M ESPE) was applied according to the manufacturer's instruction and polymerized for 10 s by a light-curing unit XL 2500. The bonded surfaces were coupled with a composite resin Filtek Z350 (3M ESPE) applied in 2 mm increments and polymerized using a curing unit XL 2500 (3M ESPE) for 40 s for each increment and to build 6 mm thick block. The restored teeth were stored in distilled water at 37o C for 24 h. After this period, the restored teeth were longitudinally sectioned across the bonded interface to produce a series of 1.0mm2 beams. The specimens were then submitted to three storage periods: 24 hours, 6 months, or 1 year. Afterwards, the storage periods, the specimens were submitted to a microtensile bond strength (_TBS) using EZ test machine (EZS, Shimadzu) at a crosshead speed of 0.5 mm/min until failure. Data were submitted to ANOVA and Tukey's HSD test (?=0.05). The bonding with sound dentin showed _TBS values significant higher when compared to caries-affected and caries-infected dentin. The 6 months and 1 year storage periods resulted in decreased bond strengths for all dentin conditions and/or treatment. The ethanol was not effective to improve the _TBS for the three dentin substrates evaluated. The CHX did not affect the 24- hour, 6 and 12 months _TBS, independent of the tested dentin substrates<br>Doutorado<br>Materiais Dentarios<br>Doutora em Materiais Dentários
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Dallmann, Robert. "Characterisation of Per mutant mice." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972545263.
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Roy, Ipsita. "Studies on methylmalonyl-CoA mutase." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240978.
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Lewis, Christopher Roger. "Chromosomal deletions in Streptococcus mutans." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297569.
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Biram, Dawn. "Spectroscopic studies of mutant myoglobins." Thesis, University of York, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292488.
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Turkenburg, Johannes Piet. "Structural studies on mutant insulins." Thesis, University of York, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306538.
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Stewart, Christine Catherine. "Toxicity of mutant membrane proteins /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/10259.
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Bycroft, Mark. "NMR studies of mutant proteins." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47373.
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Saundh, Harpal. "Targeting mutant p53 in cSCCs." Thesis, University of Dundee, 2016. https://discovery.dundee.ac.uk/en/studentTheses/29e37f0d-5ed7-483c-9a92-87212934d72b.
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Cutaneous squamous cell carcinoma (cSCC) is a type of non-melanoma skin cancer that is the 4th most common cancer registration in Scotland after BCC, lung and breast cancer. Over 30,000 cSCC incidences are reported each year in the United Kingdom. In addition, around 1 in 4 skin cancer deaths in the UK are due to cSCCs. Amongst those highly prone to developing cSCCs include organ transplant recipient, immunosuppressed, recessive dystrophic epidermolysis bullosa (RDEB) and Xeroderma Pigmentosum (XP) patients. cSCC patients that display regional metastasis have a 5-year survival rate of 25-50%, whilst this rate is close to 0% in RDEB patients with multiple cSCCs. Wild-type p53 (wt-p53) has been shown to prevent cSCC development and induce tanning and sunburn responses in skin cells. However, TP53 mutations are found in over half of all human cancers and cSCC is no exception as TP53 mutational frequency in cSCCs is around 64-87.5% (Durinck et al, 2011; South et al, 2014). The majority of TP53 mutations in cSCCs are UV-signature missense mutations, highlighting UV-radiation as one of the main risk factors for cSCC development. Mutant p53 proteins can lose wt-p53 functions, have dominant-negative effects against wt-p53 and acquire gain of function (GOF) activities. Mutant p53 GOF activity is induced by the accumulation of mutant p53 in tumour cells. Mutant p53 accumulation is not due to intrinsic properties of the mutants but requires other cellular events, possibly those known to stabilise wt-p53 under cellular stress. It is known that the TP53 mutations and mutant p53 accumulation are early steps in cSCC development. This makes skin an excellent system to investigate the early changes to p53. We have investigated the potential of targeting mutant p53 for cSCC therapy and mechanisms that promote mutant p53 accumulation in cSCCs. We selected low-passage cSCC cell lines that express hotspot mutant p53 proteins, in cSCCs and in general, by analysing TP53 mutational data from the IARC database and next generation sequencing studies performed on cSCC primary tumours by Dr South at Ninewells Hospital, Dundee. cSCC cell lines were generated from immunocompetent, transplant and RDEB patients by Dr South’s group at Ninewells Hospital, Dundee. We found that: 1. PRIMA-1MET, a small molecule reported to restore wt-p53 activity, lacked tumour selectivity as it is able to reduce cell viability in both normal skin and cSCC cells with similar potency. cSCC cell lines are relatively resistant to PRIMA-1MET compared to cell lines derived from other tumour types. 2. Mutant p53 knockdown studies performed on cSCC cell lines suggest that some p53 mutants play a pro-proliferative role. However, there is no evidence for a pro-migratory role of mutant p53 in cSCC. 3. There are no clear alterations in DNA-damage response pathways or the general ubiquitin proteasome system that could contribute to mutant p53 stabilisation in cSCC. 4. Heat shock factor 1 (HSF-1) is upregulated in cSCC compared to normal human keratinocytes (NHK). HSP90 inhibitors, 17-AAG and 17-DMAG, reduce mutant p53 protein levels suggesting that HSP90 plays a role in stabilising mutant p53 in cSCCs. 5. PR-619, a broad range deubiquitinating enzyme (DUB) inhibitor, reduces mutant p53 protein levels in a range of cSCC cell lines. This is rescued by the addition of bortezomib suggesting that DUBs can play a role in protecting mutant p53 from proteasomal degradation. Expression of HAUSP and USP10, which have been shown to stabilise wild-type p53, is generally elevated in cSCC compared to NHK. However, knockdown of these DUBs does not reduce protein levels of mutant p53 in cSCC cell lines. 6. A potential isoform of MDMX (51 kDa) is strongly upregulated in all cSCC cell lines examined. There is an association between the ability of MDMX siRNAs to deplete the 51 kDa protein and reduce mutant p53 protein levels and stability. Furthermore we show that the protein can form complexes with MDM2 in vitro and in cSCC cells. We propose that the MDMX isoform is able to stabilise mutant p53 in cSCC cells through this interaction with MDM2.
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Hunter, Jennifer Margaret. "Reprogramming a DNA methylation mutant." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/25874.
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Chemical modification of the cytosine base via the addition of a methyl group to form 5-‐methylcytosine (5-‐mC) is a well-‐studied example of an epigenetic mark, which contributes to regulation of gene expression, chromatin organisation and other such cellular processes without affecting the underlying DNA sequence. In recent years it was shown that 5-‐mC is not the only DNA modification found within the vertebrate genome. 5-‐hydroxymethylcytosine (5-‐hmC) was first described in 1952 although it wasn’t until 2009 when it was rediscovered in mammalian tissues that it sparked intense interest in the field. Research has found that unlike the 5-‐mC base from which it is derived, 5-‐hmC displays variable levels and patterns across a multitude of tissue and cell types. As such the patterns of these DNA modifications can act as an identifier of cell state. This thesis aims to characterize the methyl and hydroxymethyl profiles of induced pluripotent stem cells (iPSCs), derived from control mouse embryonic fibroblast cell line (p53-‐/-‐) as well as and methylation hypomorphic (p53-‐/-‐, Dnmt1 -‐/-‐) mutant cell lines. As such both somatic cells were subject to reprogramming with Yamanaka factors (Oct4, cMyc, Klf4 and Sox2) via the piggyback transposition technique. Successful reprogramming was confirmed by a number of techniques and outcomes, including the de novo expression of a number of key pluripotency related factors (Nanog, Sall4 and Gdf3). Reprogrammed cells were then analysed for transcriptomic changes as well as alterations to their methyl and hydroxymethyl landscapes that accompany reprogramming. Through this work I have shown that the reprogramming of MEF derived cell lines results in a global increase in 5-‐hmC for both p53-‐/-‐ and (p53-‐/-‐, Dnmt1 -‐/-‐) hypomorphic mutant cell lines – possibly through the reactivation of an alternative form of DNMT1. I demonstrate by both antibody based dot blot assay and genome wide sequencing that the reprogramming of the (p53-‐/-‐, Dnmt1 -‐/-‐) somatic cells towards a pluripotent state brings about an increase in methylation levels within the cells. This latter observation may indicate that the reprogramming of the cells is driving them towards a more wild type phenotypic state. My studies suggest that lack of DNMT1 function is not a barrier to reprogramming of somatic cells.
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Hartzoulakis, Basil. "Mechanistic studies on glutamate mutase." Thesis, University of St Andrews, 1994. http://hdl.handle.net/10023/14380.
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The coenzyme B12-dependent enzyme glutamate mutase (E.C. 5.4.99.1) catalyses the rearrangement of (2S)-glutamic acid to (2S,3S)-3-methylaspartic acid. Each of the two components of the enzyme was purified to homogeneity using a combination of low and high performance chromatographic techniques. Component E and S displayed molecular weights of 53 KDa and 13 KDa respectively as determined by gel electrophoresis, contrary to literature reports. A large number of glutamate and 3-methylaspartate analogues were synthesised and tested as substrates for the enzyme from Clostridium tetanomorphum. No rearrangement products could be detected for (2S,3R)-3-methylaspartic acid, (2S,3S)-3-ethylaspartic acid, 3-methylglutamic acid, (2S,3R)-3-methylsuccinic acid or A/-methyl-3-methylaspartic acid. Five inhibitors were discovered for the enzyme. Four of them were typical competitive inhibitors: (2S,3S)- and (2S,3R)-3-methylglutamates (Ki = 1.0 mM and Ki = 1.5 mM respectively); (2S)-homocysteic acid, Ki = 5 mM; and 1-bromo-cis-1,2-cyclopropanedicarboxylic acid (Ki= 2.2+/-0.2 mM). Finally 1-bromo-trans-1,2- cyclopropanedicarboxylic acid prevented the enzyme from processing (2S)- glutamic acid for periods of times proportional to its concentration. Our results support a radical mechanism with a protein bound glycyl radical as an intermediate, and provide evidence for the existence of two distinct conformations of the holoenzyme, prior to and after the activation of the cofactor. (2S,3R)-3- and (2S,3S)-3-Methylglutamic acids were synthesised stereospecifically by extending Schollkopf's bis-lactim ether methodology. The attack of various carbon anions at C-5 of isopropyl N-benzyl-(4S,5R)-1,2,3- oxathiazolidone-5-methyi-4-carboxyiate S,S-dioxide was not a versatile pathway. Nevertheless, the reaction of the oxathiazolidone with an allylmagnesium lithium cuprate complex gave some promising results, but more research is necessary to optimise certain problematic steps. Several different routes were evaluated for the preparation of 1-amino-1,2-cyciopropanedicarboxylic acid, but either low yields or instability of intermediates thwarted any attempts to achieve this goal. Finally 1- bromo-cis-and trans-1,2-cyclopropanedicarboxylic acids were synthesised by reacting methyl acrylate with methyl dibromoacetate in the presence of sodium hydride. The two pairs of enantiomers, cis- ((2S,3S) and (2R,3R)) and trans- ((2R,3S) and (2S,3R)) were separated by selective ester formation.
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Gustavsson, Alma. "Cloning of an aldolase mutant." Thesis, Uppsala universitet, Institutionen för kemi - BMC, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-397493.
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Isaac, Mutasa. "Commúnity Media and peace building in post-conflict Rwanda." Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-22306.
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AbstractThe main import of this case study is to understand how community radio has contributed to peace in the aftermath of the genocide in Rwanda which in essence was the massacring of the Tutsi and Hutu moderates by Hutu extremists. The inquiry embraces the citizen participation theory and a rhizomatic approach to the study of community media as its analytic lenses. This task is accomplished through expert interviews with community media practitioners. The main research question for the study is; How has community radio contributed to peace building in post-conflict Rwanda? A subsidiary question is posed: How have changes in post genocide Rwanda´s media environment impacted the operations of community radios? These questions are important in post-conflict Rwanda where one ethnic group fought the other aided by the radio amidst accusations and counter accusations of marginalisation in developmental matters and political influence.The study finds that community radio has contributed to peace by defining community in terms of region and not defining the concept along the same ethnic lines that have proven to be problematic in the past They have instead placed emphasis on homogeneity e.g. same language and culture rather than difference and have adopted a new narrative to describe the socio-economic challenges of the Rwandan people. A platform for citizen participation was created for people to share experiences and resolve disputes and regular reconciliatory messages pass through the airwaves. While there have been challenges with the restructuring of the media-legal framework which in the eyes of some resulted in too harsh media laws and strict government control, community media is one of the major benefactors of the changes. A measure of decency was established.
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Paula-Eduardo, Laila Facin de 1984. "Isolamento e identificação de compostos bioativos da geoprópolis (Melipona scutellaris) bioguiado pelo efeito antimicrobiano = Isolation and identification of bioactive compounds of geopropolis (Melipona scutellaris) bioguided by the antimicrobial effect." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288513.
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Orientadores: Pedro Luiz Rosalen, Cínthia Pereira Machado Tabchoury<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-26T11:28:01Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014<br>Resumo: Os produtos naturais, comprovadamente, têm sido uma fonte promissora para descoberta de novos compostos bioativos. Dentre eles, a própolis coletada por abelhas Apis mellifera possui atividades biológicas descritas na literatura como anticárie, antibacteriana, anti-inflamatória, entre outras. Entretanto, a maioria dos estudos sobre própolis se refere àquelas coletadas por A. mellifera e pouco se tem conhecimento de outras, como a geoprópolis, produzida por abelhas sem ferrão do gênero Melipona. Em estudos recentes, a geoprópolis apresentou promissoras atividades antimicrobiana e anti-inflamatória, porém estas pesquisas ainda não evidenciaram quais as substâncias responsáveis por tais ações biológicas, especialmente contra o biofilme oral cariogênico. Portanto, o objetivo desse trabalho foi isolar e identificar o composto ativo da geoprópolis de Melipona scutellaris com atividade contra biofilme formado por Streptococcus mutans. Este objetivo foi alcançado por meio das seguintes metodologias: 1- fracionamento bioguiado do extrato etanólico da geoprópolis (EEGP); 2- isolamento e identificação do composto ativo; 3- avaliação do potencial anticárie do composto ativo utilizando modelo in vitro de inibição de biofilme oral monoespécie. Como resultado do fracionamento bioguiado foi isolado e identificado o composto nemorosona (C33H42O4, MM= 502 g/mol), uma benzofenona prenilada. A concentração inibitória mínima da nemorosona foi de 6,25 ¿ 12,5 ?g/mL e na concentração de 100 ?g/mL foi capaz de inibir em 95% a aderência do S. mutans em biofilme formado em microplacas de fundo côncavo. Em biofilme formado em discos de hidroxiapatita, a nemorosona na concentração 250 ?g/mL (0,50 mM) reduziu 65 % do peso seco, mais de 70% dos polissacarídeos e 48% da quantidade proteica além de diminuir a viabilidade bacteriana, quando comparada com o controle negativo (veículo, p<0,05). Estes resultados não diferiram estatisticamente da clorexidina a 0,12% (1,33 mM) (p>0,05). Portanto, concluímos que a nemorosona é um composto ativo isolado e identificado da geoprópolis com atividade antibiofilme de S. mutans com capacidade de alterar a composição bioquímica da matriz do biofilme de S. mutans, o que torna este composto promissor agente químico para o controle do biofilme oral<br>Abstract: Natural products have been demonstrated a promising source to discover new bioactive compounds. Among then, the propolis collected by Apis mellifera bees has biological activity described in the literature as anticairies, antimicrobial, anti-inflammatory, besides other activities. However, most of the studies on propolis refer to those collected by A. mellifera and little is known about others as geopropolis, which is collected by stingless bees of the genus Melipona. In recent studies, geopropolis presented promising antimicrobial and anti-inflammatory activities, but these studies have not revealed which is (are) the substance(s) responsible(s) for such biological activities, especially against the cariogenic oral biofilms. Therefore, the objective of this study was to isolate and identify the active compound from Melipona scutellaris geopropolis, which has activity against the biofilm formation by Streptococcus mutans. This goal was achieved by the following methodologies: 1- bioassay-guided fractionation of the goeporpolis ethanolic extract (EEGP); 2- isolation and identification of the active compound; 3- anticarie potential assessment of the active compound using an in vitro model of inhibition of the oral mono-species biofilm. As result of the bioassay-guided fractionation, the poliprenil benzophenone compound named nemorosone (C33H42O4, MW=502 g/mol) was isolated and identified. The nemorosone¿s minimum inhibitory concentration (MIC) was 6.25 ¿ 12.5 ?g/mL and the concentration of 100 ?g/mL was capable to inhibit by 95% the adherence of S. mutans¿s biofilm formed in U-bottom microtiter plates. In biofilm formed in hydroxyapatite disks, the nemorosone concentration of 250 ?g/mL (0.5 mM) reduced 65% of the dry weight, more than 70% of the polysaccharides and 48% of the protein content. In addition, it reduced the bacterial viability when compared to negative control (vehicle, p<0.05). These results did not differ statistically from chlorhexidine 0.12% (1.33 mM) (p> 0.05). Therefore, the conclusion is that nemorosone is the active compound isolated and identified from geopropolis with antibiofilm activity that is able to alter the biochemical composition of the S. mutans biofilm matrix, it makes this chemical compound promising to oral biofilm control<br>Mestrado<br>Farmacologia, Anestesiologia e Terapeutica<br>Mestra em Odontologia
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Borges, FÃtima Maria Cavalcante. "EficÃcia antimicrobiana do digluconato de clorexidina sobre dentina humana infectada por bactÃrias cariogÃnicas: estudo in vitro e in situ." Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=3514.
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nÃo hÃ<br>O objetivo deste estudo foi avaliar in vitro e in situ os efeitos de um agente de limpeza cavitÃria a base de digluconato de clorexidina a 2% (CHX) na desinfecÃÃo de dentina cariada, bem como determinar a susceptibilidade de diferentes espÃcies a este agente antimicrobiano. Setenta blocos de dentina humana foram distribuÃdos de forma aleatÃria e submetidos a desafio cariogÃnico por um mÃtodo microbiolÃgico in vitro (n=15), bem como um in situ (n=20). No estudo in vitro, 30 blocos de dentina foram imersos por 5 dias, em caldo BHI inoculado com Streptococcus mutans, para induÃÃo de cÃrie. No estudo in situ, 20 voluntÃrios usaram dispositivos palatinos contendo dois blocos de dentina, que foram gotejados com soluÃÃo de sacarose 40%, 10 vezes ao dia, durante 14 dias. Ao final de cada perÃodo experimental, os blocos de dentina foram divididos aleatoriamente em dois grupos: Controle (soluÃÃo de NaCl a 0,9%) e CHX. Amostras de dentina infectada foram coletadas antes e 5 min apÃs cada tratamento, em seguida, as bactÃrias foram cultivadas e os microorganismos contados. Foram avaliados os seguintes microorganismos: estreptococos mutans in vitro e in situ, estreptococos totais, microorganismos viÃveis totais e lactobacilos, in situ. A reduÃÃo microbiana promovida por cada tratamento foi calculada e comparada entre os grupos pelo teste t, a susceptibilidade dos microorganismos isolados in situ foi comparada pela anÃlise de variÃncia ANOVA (= 5%). A reduÃÃo microbiana promovida pela CHX foi significativamente maior quando comparada ao grupo controle para todos os microorganismos avaliados tanto in vitro quanto in situ. No entanto, nÃo houve diferenÃa na susceptibilidade dos vÃrios microorganismos avaliados. Desta forma, a CHX foi capaz de reduzir a populaÃÃo microbiana em dentina infectada, sugerindo que esta abordagem pode ser uma ferramenta auxiliar para desinfecÃÃo de dentina cariada residual suprimindo o crescimento de microorganismos associados ao desenvolvimento de cÃrie.
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Pereira, Agnes de Fatima Faustino. "Estudo dos efeitos de um verniz contendo xilitol sobre estreptcocos do grupo mutans." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/25/25149/tde-18082010-101800/.
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O presente estudo foi dividido em quatro etapas distintas. A primeira etapa teve por objetivo avaliar a liberação de xilitol na saliva de humanos ao longo do tempo após aplicação de verniz controle e contendo 10% e 20% de xilitol. Um estudo cruzado foi realizado pela aplicação de 32 mg de cada verniz sobre as superfícies vestibulares de todos os incisivos centrais de 10 voluntários. Amostras salivares foram coletadas no baseline e após 5 min, 10 min, 15 min, 30 min, 1 h, 1 h 30 min, 2 h, 4 h e 8 h da aplicação dos vernizes para posterior análise da concentração de xilitol na saliva. Um estudo clínico foi realizado na segunda etapa com o objetivo de verificar a influência do verniz contendo xilitol a 20% sobre a contagem de estreptococos do grupo mutans provenientes de biofilme dentário. Semanalmente, 32 mg de verniz controle (grupo G1) ou verniz contendo xilitol a 20% (grupo G2) foram aleatoriamente aplicados sobre as superfícies vestibulares dos incisivos centrais de 67 crianças. Após quatro semanas de procedimento, amostras de biofilme dentário foram coletadas do terço cervical de todos os dentes presentes na cavidade bucal e a contagem relativa e absoluta dos microrganismos foi determinada. A terceira etapa objetivou analisar a influência do xilitol sobre a ultra-estrutura de Streptococcus mutans ATCC 33478 e Streptococcus sobrinus ATCC 25175. Além disso, a capacidade do xilitol e do flúor em promover estresse celular em S. mutans UA 159 geneticamente modificados (deleção do gene vicK) foi determinada na quarta etapa. As concentrações de xilitol na saliva (F=5,228, p=0,024) em diferentes tempos de coleta (F=18,24, p<0,0001) foram estatisticamente diferentes após aplicação dos vernizes contendo 10% e 20% do açúcar (etapa 1). Na etapa 2, contagens absolutas inicial e final de estreptococos do grupo mutans (Teste-t, p=0,4192) e de estreptococos totais (Teste-t, p=0,3506) não foram significativamente diferentes nos indivíduos pertencentes ao grupo G2. No entanto, uma redução significativa na porcentagem relativa inicial e final de estreptococos do grupo mutans em relação aos estreptococos totais foi observada (Teste-t, p= 0,0095). Xilitol a 20% promoveu alterações na morfologia de S. mutans ATCC 33478 e S. sobrinus, ATCC 25175, resultando em paredes celulares mais difusas e menos definidas, cápsulas 24 polissacarídicas mais dispersas e irregulares em relação ao grupo controle (etapa 3). Os tratamentos envolvendo xilitol a 1,25% e 2,5% mostraram-se capazes de produzir maior estresse celular à S. mutans geneticamente modificados quando comparados aos tratamentos com NaF a 22,5 mM e 45 mM em todos os tempos analisados (ANOVA a um critério, Teste de Tukey, p<0,05). Portanto, o verniz contendo xilitol pode ser considerado um interessante veículo para a administração do açúcar, uma vez que demonstrou propiciar uma liberação mais lenta do poliol na cavidade bucal. Além disso, a significativa redução da contagem relativa de estreptococos do grupo mutans em relação aos estreptococos totais pode auxiliar na prevenção de cárie dentária. Este estudo também demonstrou a habilidade do xilitol em produzir alterações ultra-estruturais de S. mutans ATCC 33478 e S. sobrinus, ATCC 25175, além de ser capaz de produzir estresse celular em S. mutans UA159 com deleção do gene vicK.<br>This study was divided in four distinct stages. The first one aimed to assess the xylitol release in human saliva along time after application of control, 10% or 20% xylitol varnishes. A cross-over design study was performed by application of 32 mg of each varnish on buccal surfaces of all incisors of 10 volunteers. Salivary samples were collected to analyze the xylitol concentration in baseline and after 5 min, 10 min, 15 min, 30 min, 1 h, 1 h 30 min, 2 h, 4 h and 8 h from varnishes application. A clinical study was executed in the second stage aiming observe the influence of 20% xylitol varnish on mutans streptococci counts from dental plaque. Weekly, 32 mg of control varnish (group G1) or 20% xylitol varnish (group G2) were randomly applied on buccal surfaces of central incisors of 67 children. After 4 weeks of procedures, dental plaque samples were collected from cervical of all teeth and relative and absolute counts of microorganisms were determined. The third stage aimed to analyze the effect of xylitol on the ultrastructure of Streptococcus mutans ATCC 33478 and Streptococcus sobrinus ATCC 25175. Moreover, the capacity of xylitol and fluoride to promote cellular stress in S. mutans UA 159 knockout vick gene was determined in the fourth stage. Salivary xylitol concentrations (F=5,228, p=0,024) in different collection times (F=18,24, p<0,0001) were statistically different after 10% and 20% varnishes application (stage 1). In stage 2, initial and final absolute mutans streptococci (Teste-t, p=0,4192) and total streptococci counts (Teste-t, p=0,3506) did not differ significantly in volunteers from group G2. However, a significant reduction of initial and final relative mutans streptococci counts was observed in relation to total streptococci (Teste-t, p= 0,0095). 20% xylitol promoted alterations in morphology of S. mutans ATCC 33478 and S. sobrinus, ATCC 25175, resulting in more diffuse and less defined cellular wall, more dispersive and irregular polysaccharidic capsules in comparison to control group (stage 3). 1.25% and 2.5% xylitol treatments were able to produce higher cellular stress to genetically modified S. mutans when compared to 22.5 mM and 45 mM NaF treatments throughout the time (ANOVA, Tukeys test, p<0.05). Therefore, xylitol varnish can be regarded as interesting vehicle to administer the polyol because it achieved a slower xylitol release into the oral cavity. Furthermore, a significant reduction of relative mutans streptococci counts in relation to total streptococci can aid in prevention of dental caries. The present study also demonstrated the ability of xylitol in producing ultrastructural alterations in S. mutans ATCC 33478 and S. sobrinus, ATCC 25175, besides generating cellular stress to S. mutans UA159 knockout vicK gene.
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Paschoal, Marco Aurélio Benini. "Avaliação in vitro da terapia fotodinâmica sobre microrganismos cariogênicos presentes na saliva de crianças." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/25/25133/tde-03072009-105829/.
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O surgimento de resistência bacteriana aos tratamentos convencionais tem proporcionado o desenvolvimento de novas modalidades terapêuticas para o tratamento e/ou controle da cárie dentária. Nesse contexto, a utilização da terapia fotodinâmica (TFD) é sugerida como alternativa para a inativação de microrganismos patogênicos envolvidos na gênese da cárie. O objetivo do presente estudo foi avaliar in vitro o efeito antimicrobiano da terapia fotodinâmica (TFD) sobre três culturas de S. mutans: uma cepa padrão de S. mutans (ATCC 25175) e dois isolados clínicos (43513 e 47513) oriundos da saliva de crianças. O corante (C) azul de orto-toluidina (TBO) foi utilizado associado à iluminação com LEDs (L) no comprimento de onda vermelho. Estas suspensões foram transferidas para placas de 96 orifícios, tratadas com quatro concentrações de TBO (0,25; 2,5; 25 e 250 µg/mL) e expostas a quatro dosimetrias (12; 24; 36 e 48 J/cm2) constituindo o grupo C+L+ (TFD). Suspensões adicionais foram tratadas somente com as quatro concentrações de TBO (C+L-) ou apenas com as quatro dosimetrias (C-L+). Amostras não submetidas ao tratamento com a fonte de luz nem ao corante, constituíram a condição C-L- (controle positivo). Alíquotas de 100 µL de cada orifício foram transferidas para tubos de ensaio para se verificar a presença ou ausência de crescimento microbiológico. Adicionalmente, alíquotas de 25 µL do grupo correspondente a TFD (C+L+) foram semeadas em placas de Petri, as quais foram incubadas a 370C por 48 horas para posterior visualização de halos de inibição e/ou crescimento microbiológico correspondente a efetividade ou ineficiência da TFD, respectivamente. Com o intuito de confirmar os achados, essas mesmas amostras foram submetidas à análise pela microscopia confocal a laser. Os resultados demonstraram que a TFD, em determinadas condições experimentais, foi efetiva no controle do crescimento microbiológico das espécies de S. mutans usadas neste estudo. A concentração mínima de TBO necessária para a inativação in vitro das três culturas de S. mutans foi de 2,5 µg/mL associada à dosimetria mínima de 24 J/cm2 da fonte de luz LED utilizada no estudo.<br>The increase of bacterias resistance to conventional treatment resulted in the development of new therapeutic modalities for dental caries treatment and/or prevention. In this field, the use of photodynamic therapy (PDT) is suggested as an alternative for inactivation of patogenic microrganisms involved in the etiology of tooth decay. The aim of this study was to evaluate in vitro the antimicrobian effect of the photodynamic therapy (PDT) on bacteria suspensions of S. mutans (ATCC 25175) and two suspensions (43513 and 47513) from infants saliva. Toluidine blue O (TBO) (D) and a red light-emmiting diodes (LEDs) (L) were used in association. Samples were inserted into 96 well-plate and treated with four TBO concentrations (0.25; 2.5; 25 e 250 µg/mL) and exposed to four dosimetries (12; 24; 36 e 48 J/cm2) defining the D+L+ group (PDT). Additional samples were treated only with TBO (D+L-) or only with red LEDs (D-L+). The treatment without dye and none red LED constituted the D-L- condition (positive control). Aliquots from D+L+ (TFD group) were inserted in Petri dishes, which were incubated at 370C for 48 hours. Posterior analysis of microbiologic growth, corresponding to PDT effectivity, was conducted. These samples were also submitted to laser confocal microscopy analysis for microbiologic data confirmation. The results showed PDT effectiveness for S. mutans inactivation in particular conditions. It was demonstrated that PDT was efficient to kill S. mutans species in the presence of the TBO at 2.5 µg/mL (minimum concentration) associated to 24 J/cm2 dosimetry.
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Gazola, Filho Jaime. "Influencia de concentrações subinibitórias de agentes antimicrobianos sobre a fisiologia e genética de S.mutans /." Araçatuba, 2016. http://hdl.handle.net/11449/148029.
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Orientadora: Cristiane Duque<br>Banca: Ana Claudia Okamoto<br>Banca: Marcelle Danelon<br>Banca: Natália Leal Vizoto<br>Banca: Thiago Cruvinel da Silva<br>Resumo: Streptococcus mutans é conhecido por sua capacidade de aderir, colonizar e formar biofilme nas superfícies dentárias. Para sobreviver na cavidade bucal, S. mutans coordena a expressão de vários genes em resposta aos fatores ambientais, como na presença de agentes antimicrobianos. Os objetivos deste estudo foram: 1) avaliar a influência de concentrações subinibitórias (sub-MIC) de fluoreto de sódio (NaF) e digluconato de clorexidina (Chx) sobre o crescimento planctônico; 2) avaliar a influência desses antimicrobianos em concentrações sub-MIC na formação de biofilme das cepas de S. mutans; 3) avaliar a expressão dos genes covR e vicR de cepas de S. mutans expostas aos sub-MIC de Chx e NaF. Cepas de S. mutans padrão (ATCC 25175 e UA159) e isolada de criança com cárie precoce da infância (3FV2) foram reativadas em BHI caldo e expostas a Chx e NaF para determinação da MIC e MBC. A partir desses valores, curvas de crescimento foram obtidas para as cepas de S. mutans expostas a concentrações sub-MIC de Chx (0,25 x MIC a 0,75 x MIC) e NaF (0,125 x MIC a 0,75 x MIC). Ensaios de biofilme foram realizados para as cepas de S. mutans expostas ou não aos sub-MIC dos agentes antimicrobianos (0,25 x MIC; 0,5 x MIC e 0,75 x MIC). A expressão dos genes covR e vicR foram avaliadas por PCR quantitativo para as cepas de S. mutans em condições planctônicas expostas a 0,125/0,25/0,5 x MIC de NaF e Chx. Os dados obtidos foram submetidos à análise estatística considerando p≤0,05. Os resultados mostra... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Streptococcus mutans is known for its ability to adhere, colonize and form biofilm on dental surfaces. To survive in the oral cavity, S. mutans coordinates the expression of several genes in respon se to environmental factors, such as in the presence of antimicrobial agents. The objectives of this study were: 1); to evaluate the influence of subinhibitory concentrations (sub - MIC) of chlorhexidine (Chx) and sodium fluoride (NaF) on planktonic growth 2) to evaluate the influence of sub - MIC of these agents on biofilm formation of S. mutans strains; 3) to evaluate the expression of the covR and vicR genes of S. mutans strains exposed to sub - MIC of Chx and NaF. Standard strains of S. mutans (ATCC 25175 or UA159) and clinical strain isolated from child with caries (3FV2) were reactivated in BHI broth and exposed to Chx and NaF for determination of MIC and MBC. From these values, growth curves were obtained for S. mutans strains exposed to sub - MIC concentrations of Chx (0.25 x MIC to 0.75 x MIC) and NaF (0.125 x MIC to 0.75 x MIC). Biofilm assays were performed for S. mutans strains exposed or not to the sub - MIC of antimicrobial agents (0.25, 0.5 and 0.75 x MIC). Expression of covR and vicR gen es were evaluated by quantitative PCR for strains of S. mutans under plankton conditions exposed to 0.125 / 0.25 / 0.5 x MIC of NaF and Chx. The data were submitted to statistical analysis considering p≤0.05. The results showed that Chx and NaF sub - MIC aff ected planktonic growth of S. mutans strains in a dose - dependent manner. Sub - MIC of Chx only affect the biofilm formation for ATCC 25175, and, NaF values above 0.5 x MIC caused reduction of the biofilm growth for all tested strains, in a dose - dependent m anner, except for ATCC 25175, which was also affected by all concentrations evaluated. Gradual sub - MIC concentrations (Complete abstract electronic access below)<br>Doutor
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Levitt, Nicola C. "Role of RecQ helicases in maintenance of genome integrity." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275469.
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Wheatley, Kay. "The role of the Arabidopsis LHY gene in regulating flowering time and circadian rhythms." Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365052.
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Perry, Susan Elizabeth. "A site directed mutagenic analysis of the regulatory flovoprotein NifL from Azotobacter vinelandii." Thesis, University of East Anglia, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247106.
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Darley, Daniel James. "Mechanistic investigations into coenzyme Bâ†1â†2 dependent enzymes." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364804.
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Camling, Elisabeth. "Studies of naturally-occuring antibodies to mutans stretococci in humans." Göteborg : University of Göteborg, 1991. http://catalog.hathitrust.org/api/volumes/oclc/25384123.html.
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Pina, Marcos Rogerio Rosa. "Avaliação da eficacia da escovação da lingua sobre a contagem de Estreptococos mutans e Lactobacilos da saliva." [s.n.], 1998. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289679.
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Orientador: Alcides Guimaraes<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-07-23T08:43:07Z (GMT). No. of bitstreams: 1
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Previous issue date: 1998<br>Resumo: Essa pesquisa foi desenvolvida com um grupo de 20 escolares, com 10 anos de idade, do município de Limeira. O estudo compreendeu duas fases. A primeira fase constou de 20 dias de escovação supervisionada da língua e a segunda, iniciada imediatamente após o término da primeira, constou de 20 dias de paralisação da escovação. Nenhuma modificação nas medidas de higiene oral pessoal foi executada a não ser a inclusão da escovação da língua, dividindo-se a mesma em 3 partes (lateral direita, porção central e lateral esquerda). Cada parte foi escovada com 20 movimentos, partindo da região posterior para a anterior, sem retroceder o movimento. Seguidamente à escovação, foi realizado um bochecho, por 5 segundos, com água de abastecimento público. As escovações não continham dentifrício. Para efeitos de padronização, uma escova dental (Oral B, n.o P-30) foi dada a cada um dos componentes do grupo no início da pesquisa. As amostras de saliva foram colhidas nos tempos 0, 20 e 40 dias de pesquisa para avaliações das quantidades de Unidades Formadoras de Colônias (U.F.C.) bacterianas por ml. Para tanto, utilizou-se de um teste simplificado, comercialmente conhecido pelo nome de "CARITEST SM" (para Estreptococos mutans) e "CARITEST LB" (para Lactobacilos). Os resultados obtidos para Estreptococos mutans ressaltam que, dos 20 pacientes estudados, 40% (08) apresentaram diminuição do número de colônias após 20 dias de escovação da língua, 40% (08) mantiveram seus valores iniciais e 20% (04) apresentaram valores maiores que os iniciais. Aos 40 dias do experimento, ou seja, 20 dias após a cessação da escovação da língua, pôde-se verificar que para 50% (10) dos pacientes houve um aumento de seus valores e os restantes 50% (10) mantiveram seus valores iniciais. Dessa mesma forma, verificou-se que, para Lactobacilos, dos 20 pacientes estudados, 30% (06) apresentaram diminuição do número de colônias após 20 dias de escovação da língua, 55% (11) permaneceram nos seus valores iniciais e 15% (03) apresentaram valores maiores que os iniciais. Aos 40 dias do experimento, ou seja, 20 dias após a cessação da escovação da língua, chegou-se a conclusão que para 60% (12) dos pacientes houve um alimento de seus valores, 30% (06) mantiveram seus valores iniciais e 10% (02) apresentaram valores menores que os iniciais<br>Abstract: This research has been developed with a school group of 20, in the 10 year-old age group, within Limeira City. The study has had two phases. The first consisted of 20 days of supervised brushing of the tongue and the second, of 20 days of nonbrushing, and, the second phase has begun immediately after end of the first one. No modification at the personal oral hygiene measurement has been executed unless the inclusion of the tongue brushing, wich was accomplished in such a way that it has been divided in 3 parts (lateral right, central portion and lateral left). Each part has been brushed with 20, movements from the posterior area to the previous one, without going back the movement. Afterwards, a rinsing was accomplished, for 5 seconds, with the public provisioning water. The brushing didn't contain toothpaste. For standardization effects, a toothbrush (Oral B, n° P-30) was given to each one of the components of the group in the beginning of the research. The saliva samples were picked in the times 0, 20 and 40 days of research for evaluations of the amounts of Colonies Formated Unit (C.F.U.) bacteria for ml. For so much, it was used of na easy test, wellknown commercially for "CARITEST SM' (for Streptococcus mutans) and "CARITEST LB" (for Lactobacilli). The results obtained for Streptococcus mutans, have stood out that, of the 20 studied patients, 40% (08) have presented the number of colonies decrease after 20 days of tongue brushing, 40% (08) have stayed within of their own values and 20% (04) have presented larger values than the previous ones. To the 40 days of the experiment, that is to say, 20 days after the ceasing of tongue brushing, it ean be verified that for 50% (10) of the patients there has been an increase o(their values and the remaining ones 50% (10) have been within of their own values. Thus, it ean be verified that, for Lactobacilli, of the 20 studied patients, 30% (06) have presented the number of colonies decrease after 20 days of tongue brushing, 55% (11) have stayed within of their own values and 15% (03) have presented larger values than the previous ones. To the 40 days of the experiment, that is to say, 20 days after the ceasing of the tongue brushing, it can be verified that for 60% (12) of the patients there has been an increase of their values, 30% (06) have been within of their own values and 10% (02) have presented smaller values than the previous ones<br>Mestrado<br>Fisiologia e Biofisica do Sistema Estomatognatico<br>Mestre em Odontologia
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Murata, Ramiro Mendonça. "Avaliação in vitro do efeito do kaempferol e tt-farnesol sobre o biofilme dental : inibição e viabilidade bacteriana." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288511.
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Previous issue date: 2004<br>Mestrado
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Teixeira, Alrieta Henrique. "Ação da terapia fotodinâmica antimicrobiana sobre biofilmes orais crescidos in vitro e in situ." reponame:Repositório Institucional da UFC, 2010. http://www.repositorio.ufc.br/handle/riufc/1325.
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TEIXEIRA, Alrieta Henrique. Ação da terapia fotodinâmica antimicrobiana sobre biofilmes orais crescidos in vitro e in situ. 2010. 53 f. Dissertação (Mestrado em Odontologia) - Universidade Federal do Ceará, Fortaleza, 2010.<br>Submitted by denise santos (denise.santos@ufc.br) on 2011-11-11T12:56:25Z
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Previous issue date: 2010<br>The treatment of diseases caused by oral biofilms involves mechanical removal and use of antibiotics and antiseptics which can lead to problems of bacterial resistance. Photodynamic antimicrobial chemotherapy (PACT) represents an alternative option to conventional treatment, promoting bacterial killing by photo-sensitization of microbial components. This study assessed the antimicrobial action of photodynamic therapy on oral biofilms produced in vitro and in situ using a light emitting diode (LED) associated with the photosensitizer toluidine blue O (TBO). Biofilms of Streptococcus mutans UA159 were grown on hydroxyapatite discs immersed in bathing culture and submitted to PACT after 5 days. For the in situ study, twenty-one volunteers were previously selected to use intra-oral palatal appliances containing eight blocks of human dentin during 7 days. Sucrose solution (10%) was dripped onto the dental blocks 8 times a day. The biofilm formed on one side of the device received treatment (PACT), and the opposite side acted as control. The collected material has gone through a process of disruption to the dispersion of cells and diluted in decimal series (10-1 to 10-4). In both experiments, specific culture media for the growth of total streptococci and mutans streptococci were inoculated and incubated under optimal conditions for growth of these microorganisms. Significant reductions in excess of 99.99% (p<0.05) were observed in the viability of colonies of S. mutans UA159 when exposed to TBO and LED on in vitro study. However, the biofilms formed in situ and subjected to the same experimental conditions showed no statistically significant differences (p≥0.05) in the microbiological counting when compared with control group. Therefore, we conclude that PACT was effective in microbiological reduction of S. mutans UA159 grown in an in vitro biofilm model, but very little effective on oral streptococci biofilms produced in situ.<br>O tratamento das doenças ocasionadas por biofilmes orais envolve basicamente a remoção mecânica e o uso de antibióticos e agentes anti-sépticos os quais podem originar cepas resistentes aos antimicrobianos tradicionais. A Terapia Fotodinâmica Antimicrobiana (TFDA) apresenta-se como uma opção alternativa ao tratamento clássico, promovendo a morte bacteriana por meio da fotossensibilização dos componentes microbianos. Este estudo verificou a ação antimicrobiana da terapia fotodinâmica sobre biofilmes orais produzidos in vitro e in situ utilizando um diodo emissor de luz (LED) associado ao fotossensibilizador azul de orto-toluidina (TBO). No estudo in vitro, biofilmes de Streptococcus mutans UA159, foram formados sobre discos de hidroxiapatita utilizando um modelo de banhos de cultura e submetidos à TFDA após 5 dias. Para o estudo in situ, vinte e um voluntários foram previamente selecionados para utilizar dispositivos intra-orais palatinos contendo 8 blocos de dentina humana durante 7 dias. Solução de sacarose 10% foi gotejada sobre os blocos dentais 8 vezes ao dia. O biofilme formado em um dos lados do dispositivo recebeu tratamento da TFDA, e o lado oposto serviu como grupo controle. O material coletado passou por um processo de disrupção para a dispersão das células e diluição em série decimal de 10-1 a 10-4. Em ambos os experimentos, meios de cultura específicos para o crescimento de estreptococos totais e estreptococos do grupo mutans foram inoculados e incubados em condições ideais para o crescimento desses microrganismos. Reduções significativas acima de 99,99% (p<0.05) foram observadas na viabilidade das colônias de S. mutans UA159 quando expostos ao TBO e LED no estudo in vitro. Entretanto, nos biofilmes formados in situ e submetidos às mesmas condições experimentais, não foram verificadas diferenças estatisticamente significantes (p≥0.05) da contagem microbiana quando comparadas ao grupo controle. Portanto, podemos concluir que a TFDA foi efetiva na redução microbiológica de S. mutans UA159 crescidos em modelo de formação de biofilme in vitro, mas, pouco efetiva sobre biofilmes de estreptococos orais formados in situ.