Thesis (M. Sc. (Biochemistry))--Mahidol University, 1979. / Supported by the Faculty of Graduate Studies and the National Research Council.

Thesis (Ph. D.)--Columbia University, 1933. / Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: p. 15.

Thesis (Ph. D.)--University of Manitoba, 1971. / Typescript (Photocopy). Includes bibliographical references (leaves [176]-190).

Thesis (Ph. D.)--University of Manitoba, 1971. / Typescript (Photocopy). Includes bibliographical references (leaves [176]-190).

Thesis (M.S.)--Baylor University, 2006. / Includes bibliographical references (p. 77-80).

Orientadores: Lívia Maria Andaló Tenuta, Jaime Aparecido Cury / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-17T11:14:39Z (GMT). No. of bitstreams: 1 Fernandes_JulianadeKassiaBraga_M.pdf: 1468971 bytes, checksum: b69a8db4f9c99d75424124a9bd67e50a (MD5) Previous issue date: 2010 / Resumo: Depósitos minerais do tipo fluoreto de cálcio ("CaF2") são formados no esmalte após aplicação tópica profissional de flúor (ATPF). Esses depósitos atuam como um reservatório de íons flúor para o fluido do biofilme, os quais reduzem a desmineralização no esmalte. Neste trabalho, a hipótese de que o "CaF2" seja dissolvido mais rapidamente mediante desafios cariogênicos foi testada, assim como a influência do uso de dentifrício fluoretado nessa dissolução. Para isso, foi conduzido um estudo in situ, cruzado e duplo-cego com duas fases de 14 dias cada, nas quais 12 voluntários utilizaram um dispositivo intrabucal palatino contendo 12 blocos de esmalte tratados com flúor fosfato gel acidulado (12.300 ppm F, pH 3,6-3,9) no primeiro dia de cada fase experimental. Adicionalmente, dois blocos foram fixados com cera na porção anterior do dispositivo e 30 minutos após a ATPF foram retirados para a determinação do "CaF2" formado logo após o tratamento com fluoreto. Durante o período experimental, foi gotejada solução de sacarose a 20% sobre os blocos de esmalte nas freqüências de 2 ou 8X ao dia. Três vezes ao dia, os voluntários utilizaram dentifrício fluoretado (1100 µg F/g, NaF) ou não fluoretado. Após 2, 7 e 14 dias de uso do dispositivo, os blocos de esmalte foram coletados para a determinação do "CaF2" remanescente. A extração do "CaF2" foi feita com solução de KOH M, em duas extrações seqüenciais por 24 e 6 horas. Para análise estatística, os voluntários foram considerados blocos estatísticos (n=12) e o nível de significância adotado foi de 5%. A concentração do "CaF2" formado sobre os blocos de esmalte após a ATPF diminuiu em função do tempo (p<0,0001), embora 2 semanas após a ATPF continuasse mais alta do que blocos de esmalte não tratados com ATPF. Sob uso de dentifrício fluoretado, a dissolução do "CaF2" foi reduzida (p=0,0115), porém a freqüência de consumo de sacarose não parece ter interferido nessa dissolução (p=0,226). Os resultados sugerem que a dissolução do "CaF2" parece não ter sido influenciada pela freqüência de consumo de sacarose e que sua manutenção é favorecida pelo uso concomitante de dentifrício fluoretado. / Abstract: Calcium fluoride-like ("CaF2") deposits are formed on enamel after professional topical fluoride application, and they can serve as a reservoir of fluoride ions to the biofilm fluid, to reduce enamel demineralization. In the present study, the hypothesis that "CaF2" is more readily dissolved during a higher cariogenic challenge was tested. Also, the effect of exposure to fluoride dentifrices on "CaF2" dissolution was evaluated. Thus, a crossover, double-blind and in situ study was conducted in 2 phases of 14 days each. In each phase, 12 volunteers used intraoral palatal appliances containing 12 enamel blocks treated with acidulated phosphate fluoride, APF (12,300 ppm F, pH 3,6-3,9) on the first day of each phase. Additionally, two blocks were fixed with wax on the palatal appliance and removed 30 minutes after treatment with APF to determine the concentration of "CaF2" formed. During the experimental period, the enamel blocks were exposed to 20% sucrose solution 2X or 8X/day. Three times a day, the volunteers used fluoride dentifrice (1100 µg F/g, NaF) or non-fluoride dentifrice. On the 2th, 7th e 14th day of each phase, enamel blocks were collected and the remaining "CaF2" concentration was determined. For "CaF2" determination, blocks were immersed in 1.0 M KOH, for 24 and 6 h. Data was statistically analyzed considering the volunteers as statistical blocks (n=12) and the significance limit was set at 5%. "CaF2" concentration decrease with time (p<0.0001), but was still higher than enamel blocks not treated with APF 2 weeks after APF application. Under fluoride dentifrice use, "CaF2" dissolution was reduced (p=0.0115), but the frequency of sucrose exposure did not seem to have affected it (p=0.226). The findings suggest that the frequencies of sucrose exposure did not influence the "CaF2" dissolution; and that its maintenance is facilitated by the concurrent use of fluoride dentifrice. / Mestrado / Cariologia / Mestre em Odontologia

Detritylation of tri-O-trityl-penta-O-acetyl sucrose with catalytic bydrogenolysis or graded hydrolysis with aqueous acetic acid gave in yields up to 60% a new crystal line penta-O-acetyl sucrose derivative. Methylation of the pentaacetate with the Purdie reagents, followed by deacetylation and chromatographic purification gave a sirupy tri-O-methyl sucrose which was shown to be 1’, 4, 6' -tri-O-methyl sucrose by periodate oxidation and by hydrolysis to equal parts of 4-O-methyl-D-glucose and 1, 6-di-O-methyl-D-fructose. The glucose derivative was identified by paper chromatography, specific rotation and by conversion to the known, crystalline osazone, and the structure of the new sirupy 1, 6-di-O-raethyl-D-fruetose was established by analysis, periodate oxidation, paper chromatographic behavior and the specific rotation. Deacetylation of tri-0-trityl-penta-O-acetyl sucrose gave an amorphous tri-O-trityl sucrose and methylation of this compound with the Purdie reagents, followed by detritylation with aqueous acetic acid gave a sirupy penta-O-methyl sucrose derivative, which was identified as 2, 3, 3', 4, 4’ -penta-O-methyl sucrose by hydrolysis to equal parts of the known 2, 3, k -tri-O-methyl-D-glueose and 3, 4 -di-O-methyl-D-fructose. It was therefore established that the trityl groups in the original tri-O-trityl-penta-O-acetyl sucrose occupied the three primary positions (1’, 6 and 6’) in the sucrose molecule and that acetyl migration from C4 to C6 in the glucose moiety had occurred during the synthesis of the tri-O-methyl sucrose. Vinylation of 1: 2-3: 4-di-O-isopropylidene-D-galactose with vinyl acetate after the method of Adelraan gave after catalytic hydrogenation followed by removal of the acetone groups a 0.7% yield of sirupy 6-O-ethyl-D-galactose. The new galactose derivative was identified by comparison with an authentic sample synthesized by direct ethylation of 1; 2 -3: 4 -di-O-iaopropylidene-D-galactose. Preliminary studies of the vinylation of the new crystalline penta-O-acetyl sucrose are reported. The action of Dowex I on several acetates of non-reducing carbohydrates was found to result in deacetylation in nearly quantitative yields. / Science, Faculty of / Chemistry, Department of / Graduate

Bibliography: pages 143-154. / This dissertation forms part of the study on the molecular biology of the aerobic, collagenolytic, halotolerant, gram-negative organism Vibrio alginolyticus. The cloning, expression and regulation of the v. alginolyticus sucrose utilization system in Escherichia coli is discussed and the results of a molecular analysis of the sucrase gene (scrA) are presented. The clone pVSlOO, containing a sucrose utilization system, was isolated from a genomic library of v. alginolyticus. Plasmid pVSlOO was mapped and the origin of its insert determined by Southern blotting and DNA hybridization. The number and sizes of the polypeptide products encoded by plasmid pVSlOO were determined by DNAdirected cell-free protein synthesis. The capsule, produced by transformed and untransformed E. coli JA221 cells, was shown to be independent of the presence of plasmid pVSlOO. The sucrase activity assay was optimized with respect to time, pH, temperature and salt requirements.

In general, the velocity of inversion of sucrose ie a function of several variables; namely, the temperature, the viscosity, and the concentrations of hydrogen ions, undissociated acid, sucrose, added salts, and non-electrolytes. It can readily be seen, then, that this reaction offers a broad field for research with decidedly varied and diversified lines of attack.

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