Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [95]-98).

Made available in DSpace on 2014-06-11T19:28:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-03-27Bitstream added on 2014-06-13T20:17:45Z : No. of bitstreams: 1 rocha_frg_me_arafo.pdf: 2074950 bytes, checksum: 44b81ca3437b0380ff6a9431b98cf128 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A regeneração periodontal ainda representa um importante desafio, devido a limitações na efetividade e imprevisibilidade das abordagens clínicas. O condicionamento radicular e a utilização de mediadores biológicos, como os fatores de crescimento, são duas das técnicas que tem sido estudadas para esta finalidade; também tem sido proposta a combinação de ambas. Foi avaliado in vitro o efeito do condicionamento ácido da dentina na liberação de bFGF e BMP-7 aplicados topicamente de forma isolada ou associados, além da influência de tais tratamentos na expressão de genesalvo relacionados ao metabolismo de tecido conjuntivo mineralizado e não mineralizado em três tipos celulares relevantes para o processo regenerativo no microambiente periodontal. Espécimes de dentina bovina foram subdivididos em dois grupos: não condicionados e condicionados com ácido cítrico 25% durante 3 minutos. bFGF recombinante humano (10 e 50 ng), BMP-7 (100 e 300 ng) e associação bFGF/BMP-7 (50 ng e 100 ng, respectivamente) foram suspendidos em 50 μL de meio de cultura e aplicados topicamente sobre a dentina. A liberação de fatores de crescimento aplicados topicamente sobre a dentina condicionada e não condicionada foi determinada por meio de ELISA. Linhagens celulares de camundongos – fibroblastos do ligamento periodontal, cementoblastos e células do estroma ósseo – foram plaqueadas sobre os espécimes de dentina com e sem condicionamento ácido prévio, tratados ou não com os fatores de crescimento. Após 24 horas, as células aderidas sobre as amostras de dentina foram coletadas, o RNA total extraído e a expressão gênica de colágeno 1-alfa1, fibronectina e Runx2 foi avaliada por RTqPCR. Os resultados encontrados neste estudo indicam que os fatores de crescimento são retidos pela dentina após aplicação tópica... / Periodontal regeneration still poses a challenge both in terms of predictability and magnitude of effect. Chemical root conditioning and the use of biological mediators are two strategies studied to improve the results of regenerative therapies. The objective of this study was to determine the effect of acid conditioning of dentin on the release of topically applied bFGF and BMP-7, isolated or associated. We also evaluated the impact of such treatment in the expression of target genes related to the metabolism of mineralized connective tissue and non-mineralized in three cell types relevant for the regenerative process in the periodontal microenvironment. Dentin specimens, which were obtained from bovine teeth, were divided into two groups: non-conditioned and conditioned with 25% citric acid for 3 minutes. Human growth factors produced by recombinant DNA technology were diluted in 50 mL of culture medium and topically applied on the dentin in the following amounts: recombinant human bFGF (10 and 50 ng), BMP-7 (100 and 300 ng) and associated bFGF/BMP-7 (50 ng and 100 ng, respectively). The released of growth factor topically applied on the conditioned and non-conditioning dentin samples was determined by ELISA. Murine cell lines - periodontal ligament fibroblasts, cementoblasts and bone marrow stromal cells - were grown on dentin specimens with and without prior acid conditioning and application of growth factors. After 24 hours, the cells adhered on the samples of dentin were collected, total RNA extracted and gene expression of collagen 1-alpha 1, fibronectin and Runx2 was determined by RT-qPCR. The results of this study indicate that: growth factors are retained by dentin after topical application and that the peak release occurs in two hours; the conditioning of dentin with citric acid favored the retention of topically applied growth... (Complete abstract click electronic access below)

Swallowing is a complex neurophysiological process involving the activation of several components of the central nervous system with bilateral but asymmetric representations of swallowing musculature in the motor cortex. Difficulty in swallowing (dysphagia) in stroke patients has been reported by up to 50% of victims, and can increase morbidity and mortality in this population due to the development of aspiration pneumonia and malnutrition. One of the common factors that predispose patients to dysphagia after a stroke is believed to be the reduced sensory awareness in the oropharyngeal area, which affects the swallowing process. The uses of diet modification to reduce thin liquid aspiration have gained interest but are often unpalatable or have limited success. Carbonated liquid have shown some beneficial effects in swallowing behaviour. However, there is very little evidence to support this intervention. Therefore, the aim of this thesis is to investigate the neurophysiological and behavioural effects of carbonated liquids on swallowing in healthy volunteers.The effects of carbonated solutions on swallowing performance compared to non-carbonated solutions (still water) was investigated in a pilot study and (still water and citric acid) in the main study using reaction time task (chapter 2). Carbonation appears to alter swallowing performance compared to other liquids by improving complex tasks. In addition, beneficial neurophysiological effects of carbonated liquids were evident after 10 minutes of carbonated liquid swallowing compared to still water and citric acid solution in healthy volunteers (chapter 3).In chapter 4, the response of the healthy swallowing motor cortex to carbonated liquids following application of a virtual lesion compared to still water and saliva swallowing, was investigated. Carbonated liquids were able to reverse the inhibitory effect induced by 1 Hz rTMS to the dominant pharyngeal motor representation. Moreover, the beneficial effects of carbonated liquids on swallowing performance, measured with a swallowing reaction times task after application of a virtual lesion was observed in a pilot investigation in healthy volunteers (chapter 5). These data demonstrate that carbonated liquids have beneficial neurophysiological and swallowing performance effects and support notion that the chemical properties of carbonated liquids may provide the required peripheral sensory information that alter the brain swallowing function, which leads to an improvement in the swallowing performance of stroke dysphagic patients. These data lay the foundation for considering the use of carbonation as facilitating stimuli in dysphagic patients.

Orientador: José Eduardo Cezar Sampaio / Coorientador: Carlos Rossa Junior / Banca: Márcio Zaffalon Casati / Banca: Luis Carlos Spolidório / Resumo: A regeneração periodontal ainda representa um importante desafio, devido a limitações na efetividade e imprevisibilidade das abordagens clínicas. O condicionamento radicular e a utilização de mediadores biológicos, como os fatores de crescimento, são duas das técnicas que tem sido estudadas para esta finalidade; também tem sido proposta a combinação de ambas. Foi avaliado in vitro o efeito do condicionamento ácido da dentina na liberação de bFGF e BMP-7 aplicados topicamente de forma isolada ou associados, além da influência de tais tratamentos na expressão de genesalvo relacionados ao metabolismo de tecido conjuntivo mineralizado e não mineralizado em três tipos celulares relevantes para o processo regenerativo no microambiente periodontal. Espécimes de dentina bovina foram subdivididos em dois grupos: não condicionados e condicionados com ácido cítrico 25% durante 3 minutos. bFGF recombinante humano (10 e 50 ng), BMP-7 (100 e 300 ng) e associação bFGF/BMP-7 (50 ng e 100 ng, respectivamente) foram suspendidos em 50 μL de meio de cultura e aplicados topicamente sobre a dentina. A liberação de fatores de crescimento aplicados topicamente sobre a dentina condicionada e não condicionada foi determinada por meio de ELISA. Linhagens celulares de camundongos - fibroblastos do ligamento periodontal, cementoblastos e células do estroma ósseo - foram plaqueadas sobre os espécimes de dentina com e sem condicionamento ácido prévio, tratados ou não com os fatores de crescimento. Após 24 horas, as células aderidas sobre as amostras de dentina foram coletadas, o RNA total extraído e a expressão gênica de colágeno 1-alfa1, fibronectina e Runx2 foi avaliada por RTqPCR. Os resultados encontrados neste estudo indicam que os fatores de crescimento são retidos pela dentina após aplicação tópica... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Periodontal regeneration still poses a challenge both in terms of predictability and magnitude of effect. Chemical root conditioning and the use of biological mediators are two strategies studied to improve the results of regenerative therapies. The objective of this study was to determine the effect of acid conditioning of dentin on the release of topically applied bFGF and BMP-7, isolated or associated. We also evaluated the impact of such treatment in the expression of target genes related to the metabolism of mineralized connective tissue and non-mineralized in three cell types relevant for the regenerative process in the periodontal microenvironment. Dentin specimens, which were obtained from bovine teeth, were divided into two groups: non-conditioned and conditioned with 25% citric acid for 3 minutes. Human growth factors produced by recombinant DNA technology were diluted in 50 mL of culture medium and topically applied on the dentin in the following amounts: recombinant human bFGF (10 and 50 ng), BMP-7 (100 and 300 ng) and associated bFGF/BMP-7 (50 ng and 100 ng, respectively). The released of growth factor topically applied on the conditioned and non-conditioning dentin samples was determined by ELISA. Murine cell lines - periodontal ligament fibroblasts, cementoblasts and bone marrow stromal cells - were grown on dentin specimens with and without prior acid conditioning and application of growth factors. After 24 hours, the cells adhered on the samples of dentin were collected, total RNA extracted and gene expression of collagen 1-alpha 1, fibronectin and Runx2 was determined by RT-qPCR. The results of this study indicate that: growth factors are retained by dentin after topical application and that the peak release occurs in two hours; the conditioning of dentin with citric acid favored the retention of topically applied growth... (Complete abstract click electronic access below) / Mestre

No description available.

Orientador: Osvaldir Pereira Taranto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-24T04:56:08Z (GMT). No. of bitstreams: 1 Zanella_Karine_M.pdf: 2631881 bytes, checksum: f5478ae14939fdabde9f610a2bed60a8 (MD5) Previous issue date: 2013 / Resumo: A laranja é utilizada no Brasil principalmente no processamento de suco, o qual gera entre 40-60% (em peso) de resíduos líquidos e sólidos, que posteriormente são utilizados na produção de subprodutos. A casca da laranja é composta por flavedo (porção colorida) e albedo (porção branca e esponjosa) que, quando desidratados são utilizados no processo de extração da pectina, utilizada principalmente em indústrias alimentícias e farmacêuticas. Este trabalho teve como objetivo estudar a influência das variáveis operacionais da secagem convectiva, temperatura (40, 55 e 70 °C) e velocidade do ar (0,1, 0,2 e 0,3 m.s-1), no rendimento, na qualidade e nas características da pectina extraída da casca da laranja-pera (Citrus sinensis L. Osbeck). Os experimentos foram realizados em secador de leito fixo e os dados cinéticos foram avaliados através da modelagem matemática por aplicação dos modelos de Page, Henderson e Pabis e de Midilli. Este último foi o que melhor ajustou os dados experimentais, tanto para a secagem do albedo quanto do flavedo. As condições operacionais utilizadas na extração da pectina, do albedo e do flavedo foram: temperatura (80°C), velocidade de agitação (650 rpm) e pH (2,5). O agente extrator utilizado para o processo de extração foi a mistura entre água e ácido cítrico. Os maiores valores de rendimento obtido foram de 38,21% de pectina seca por albedo seco (g/g) (Pectina-A) e de 29,35% de pectina seca por flavedo seco (g/g) (Pectina-F), os quais foram desidratados nas seguintes condições de secagem: 70°C e 0,10 m.s-1 para o albedo e 40 ºC e 0,1 m.s-1 para o flavedo. Foi verificado pela análise de infravermelho por transformada de Fourier (FTIR), que tanto a Pectina-A quanto a Pectina-F, apresentaram grau de esterificação acima de 50%, sendo caracterizadas como pectinas de alto teor de metoxilação (ATM). Além disto, as pectinas foram analisadas quanto ao seu peso molecular pela técnica de cromatografia de permeação em gel (GPC) e variaram entre 337,41 e 606,85 para a Pectina-A e entre 487,92 e 1702,00 para a Pectina-F. A análise da qualidade das pectinas foi realizada pela determinação do teor de ácido galacturônico (AGA) por espectrofotometria. Os maiores valores de AGA foram de 93,64% para a Pectina-A e de 93,29% para a Pectina-F. Pela análise dos dados foi constatado que não houve influência das variáveis operacionais de secagem nas pectinas obtidas. Contudo, verificou-se que independente da configuração escolhida durante o processo de secagem, todas as pectinas apresentaram alta qualidade e podem ser utilizadas como pectinas comerciais. Portanto, concluiu-se que o processo de obtenção da pectina utilizado neste estudo é viável / Abstract: The orange production in Brazil is mainly directed to juice processing which generates ca. 40-60% (weight) of solid and liquid wastes, which are subsequently used in the production of by-products. The orange peel is composed of flavedo (colored portion) and albedo (the white and spongy portion) which when dried are used for the extraction process of pectin with great interest in pharmaceutical and food industries. The aim of this work were to study the influence of the operating variables of convective drying, temperature (40, 55 and 70 °C) and air velocity (0,1, 0,2 and 0,3 m.s-1), on the yield, quality and characteristics of pectin extracted from "Pera? sweet orange peel (Citrus sinensis L. Osbeck). The experiments were carried out in a fixed bed dryer and the drying kinetics data were evaluated through the application of mathematical modeling, by using the following models: Page, Henderson and Pabis and Midilli. The latter one was the best model that fitted the experimental data, for drying both albedo and flavedo. The operating conditions used for extraction of pectin, from albedo e flavedo, were: temperature (80 °C), stirring rate (650 rpm) and pH (2,5). The extracting agent used for the extraction process was a mixture of water and citric acid. The highest yield values obtained were 38,21% of dried pectin for dried albedo (g/g) (Pectin-A) and 29,35% of dried pectin by dried flavedo (g/g) (Pectin-F), which were dehydrated in the following conditions: 70 °C and 0,10 m.s-1 for the albedo and 40 °C and 0,1 m.s-1 for the flavedo. It was found by analysis of Fourier transform infrared spectroscopy (FTIR) that both Pectin-A and Pectin-F showed a degree of esterification above 50%, being characterized as high methoxyl pectin (ATM). In addition, the pectin were analyzed for its molecular weight by the technique of gel permeation chromatography (GPC), and varied between 337,41 and 606,85 for Pectin-A and between 487,92 and 1702,00 for Pectin-F. The quality of pectin was obtained by determination of galacturonic acid (AGA) by spectroscopic analyzes. The highest values from AGA were 93,64% for Pectin-A and 93,29% for Pectin-F. From the data obtained, it was found that there was no influence of the operating variables of drying on the pectin. However, it was found that regardless of the chosen configuration during the drying process, all pectin had a high quality and can be used as commercial. Therefore, is possible to conclude that the process of obtaining pectin, used in this study, is viable / Mestrado / Engenharia de Processos / Mestra em Engenharia Química

A biomodificação radicular empregando ácido cítrico tem sido utilizada visando à reinserção dos tecidos periodontais a raízes expostas à doença periodontal. Entretanto, a grande diversidade metodológica entre os estudos ainda não possibilitou o estabelecimento de um protocolo amplamente aceito quanto à concentração e tempo de aplicação do ácido. Assim, 32 dentes extraídos por doença periodontal avançada forneceram 63 fragmentos radiculares que, após raspagem manual, foram divididos nos seguintes grupos de tratamento: Grupo AC-10-90: desmineralização com ácido cítrico a 10% em pH 1, durante 90 segundos; Grupo AC-10-120: desmineralização com ácido cítrico a 10% em pH 1, durante 120 segundos; Grupo AC-10-180: desmineralização com ácido cítrico a 10% em pH 1, durante 180 segundos; Grupo AC-50-90: desmineralização com ácido cítrico a 50% em pH 1, durante 90 segundos; Grupo AC-50-120: desmineralização com ácido cítrico a 50% em pH 1, durante 120 segundos; Grupo AC-50-180: desmineralização com ácido cítrico a 50% em pH 1, durante 180 segundos; Grupo C (controle): lavagem com soro fisiológico. Sobre as superfícies tratadas foram cultivados fibroblastos do ligamento periodontal humano por 24, 48 e 72 horas. A ampliação dos túbulos dentinários, morfologia celular e a porcentagem das superfícies radiculares recobertas por células foram avaliadas em microscopia eletrônica de varredura. As imagens microscópicas das superfícies recobertas por células foram comparadas pelo teste não paramétrico de Kruskal-Wallis seguido pelo teste de Dunn e na ampliação dos túbulos pelo teste de variância a dois critérios (ANOVA) complementado pelo teste de Tukey, em 5% de significância, ambos realizados por um programa computadorizado comparando os resultados entre os grupos. A Com exceção do grupo C, em todos os grupos houve aumento crescente da cobertura da superfície radicular por fibroblastos com o tempo. A maior área de cobertura foi apresentada pelo grupo AC-10-90 (98,82±2,57%) às 24 horas e essa diferença foi significante (p<0,001) em comparação aos grupos AC-50-90 (64,94±20,60%), AC-50-180 (56,59±35,42%) e C (0,06±0,24%). Nas demais comparações de tempo de aplicação e tempo de cultura, predominou a superioridade dos grupos tratados por ácido cítrico a 10% sobre os de 50%, porém, sem significância estatística. Todos os grupos teste foram significantemente superiores aos controle em todos os tempos de cultura. O menor valor médio para o diâmetro dos túbulos dentinários expostos pelos tratamentos foi apresentado pelo grupo AC-10-90 (4,55±0,69 &#x3BC;m) que diferiu significantemente (p<0,001) dos grupos AC-10-120 (5,33±0,95 &#x3BC;m), AC-10-180 (5,54±1,56 &#x3BC;m) e AC-50-180 (5,56±1,22 &#x3BC;m). Esse último apresentou a maior ampliação, porém sem diferença significante em relação aos demais grupos. Os fibroblastos apresentaram-se mais espalhados, achatados e com menor definição de limites nos grupos tratados com ácido cítrico a 10% do que nos de 50%, cujas células apresentavamse fusiformes e arredondadas. Concluiu-se que o ácido cítrico a 10% por 90 segundos produziu superfície mais favorável à proliferação celular com características morfológicas de estágios mais avançados de diferenciação e área de cobertura superficial por fibroblastos mais extensa no período inicial de cultura do que na concentração de 50%. A ampliação dos túbulos dentinários pareceu não influenciar a cobertura superficial por fibroblastos. Estudos subsequentes devem investigar a influência das propriedades químicas do agente biomodificador radicular para contribuir para a elucidação das diferenças produzidas no comportamento celular. / The root biomodification employing citric acid has been used in order to reattach periodontal tissues to root surface exposed to periodontal disease. However, the methodological diversity among studies has not allowed the establishment of a widely accepted protocol as the concentration and time of acid application. Thus, 32 teeth were extracted due to advanced periodontal disease, so that 63 root fragments were provided. After scaling and root planning, the fragments were divided into the following treatment groups : AC-10-90 group: demineralization with 10% citric acid at pH 1 for 90 seconds; AC-10-120 group: demineralization with 10% citric acid at pH 1 for 120 seconds; AC-10-180 group: demineralization with 10% citric acid at pH 1 for 180 seconds; AC-50-90 group: demineralization with 50% citric acid at pH 1 for 90 seconds; AC-50-120 group: demineralization with 50% citric acid at pH 1 for 120 seconds; AC-50-180 group: demineralization with 50% citric acid at pH 1 for 180 seconds; group C (control) : rinsing with saline solution. On the treated surfaces, fibroblasts from human periodontal ligament were cultured by 24, 48 and 72 hours. The enlargement of the dentinal tubules, cell morphology and the percentage of root surface covered by cells were evaluated by scanning electron microscopy. Those microscopic images from the root surfaces covered by cells were compared by the nonparametric Kruskal-Wallis test followed by Dunn\'s test and the enlargement of tubules by two variance (ANOVA) complemented by the Tukey test, both performed by a computer program comparing the results between the groups, at 5% significance. With the exception of group C, all groups showed increasing coverage of the root surface by fibroblasts over time. The largest area of coverage was presented by AC-10-90 (98.82±2.57%) at 24 hours and this difference was significant (p <0.001) compared to AC-50-90 (64.94±20.60%), AC-50-180 (56.59±35.42%) and C (0.06±0.24%). In other comparisons the application time and culture time groups treated with citric acid at 10% were superior to groups of 50%, without statistical significance. All test groups were significantly better than the control ones at all times of culture. The shortest average diameter of dentinal tubules exposed by the treatments was presented by AC-10-90 (4.55±0.69 &#x3BC;m) group that differed significantly (p<0,001) from AC-10-120 (5 groups 33±0.95 &#x3BC;m), AC-10-180 (5.54±1.56 &#x3BC;m) and AC-50-180 (5.56±1.22 &#x3BC;m). This last showed the highest enlargement, but without significant difference compared to the other groups. The fibroblasts were more spread, flattened and had less identifiable limits in the groups treated with citric acid 10% than those in 50% which cells had become rounded and spindle. It was concluded that the demineralization with 10% citric acid for 90 seconds produced more favorable surface to cell proliferation, more morphological characteristics of later stages of differentiation and larger surface area coverage by fibroblasts in the initial periods of culture than any of the groups treated with 50% citric acid. The enlargement of dentinal tubules did not seem to influence the surface coverage by fibroblasts. Subsequent studies should investigate the influence of the chemical properties of the root conditioner agent on the root surfaces in order to contribute to the elucidation of the differences produced in the cell behavior.

Pesquisas prévias evidenciaram que a desmineralização óssea com ácido cítrico melhora a consolidação de enxertos autógenos em bloco e favorece o espalhamento e a morfologia de pré-osteoblastos em cultura. Os resultados promissores encontrados com o ácido cítrico levantaram a suspeita de que a tetraciclina ácida pudesse suscitar efeitos semelhantes. Assim, este estudo se propôs a avaliar comparativamente o comportamento de células pré-osteoblásticas MC3T3-E1 cultivadas sobre superfícies ósseas de calvária de ratos desmineralizadas com tetraciclina ácida (50mg/mL) e com ácido cítrico (10%, pH1) em diferentes tempos de aplicação. Foram removidas 126 amostras ósseas bicorticais da calvária de 63 ratos Wistar adultos machos empregando broca trefina de 5 milímetros de diâmetro. As amostras foram distribuídas aleatoriamente em um dos seguintes grupos de estudo (n=18): AC 15 no qual as amostras foram desmineralizadas por ácido cítrico durante 15 segundos; AC 30, no qual as amostras foram desmineralizadas por ácido cítrico durante 30 segundos; AC 60, no qual as amostras foram desmineralizadas por ácido cítrico durante 60 segundos; TCN 15 no qual as amostras foram desmineralizadas por tetraciclina durante 15 segundos; TCN 30, no qual as amostras foram desmineralizadas por tetraciclina durante 30 segundos; TCN 60, no qual as amostras foram desmineralizadas por tetraciclina durante 60 segundos e C, grupo controle formado por amostras não desmineralizadas. Os pré-osteoblastos foram cultivados sobre as amostras por 24, 48 e 72 horas (n= 6) para serem examinadas à microscopia eletrônica de varredura. Vinte e uma amostras coletadas de outros 11 animais foram distribuídas entre os mesmos grupos e analisadas com espectroscopia de energia dispersiva (EDS) para análise da composição química superficial (n=3). A área de recobrimento superficial por células foi significantemente maior após 24 e 48 horas de cultura nos grupos AC15 (60,38% e 100% respectivamente), AC30 (99,32% e 100% respectivamente), AC60 (99,22% e 100% respectivamente), TCN15 (96,73% e 70,24% respectivamente) e TCN30 (64,72% e 57,40% respectivamente) do que nos grupos TCN60 (9,67% e 51,45% respectivamente) e C (5,99% e 31,83% respectivamente). Às 72 horas os grupos apresentaram recobrimento praticamente completo das superfícies ósseas por células, com exceção do grupo TCN60 (56,15%). As células apresentaram-se com morfologia compatível com em estágios mais avançados de diferenciação nos grupos que sofreram desmineralização do que no controle. As variações nas porcentagens anatômicas (A%) dos elementos C, O, Na, Mg, P e Ca foram insuficientes para justificar mudanças no comportamento celular. Concluiu-se que a desmineralização quer por ácido cítrico ou tetraciclina de superfícies ósseas são favoráveis para o crescimento e diferenciação de células pré-osteblásticas especialmente quando empregada conforme os grupos AC30 e TCN15. Os mecanismos por trás desses resultados ainda carecem de elucidação. / Previous researches have demonstrated that bone demineralisation by citric acid improves the consolidation of bone autografts and promotes spreading and morphology of pre-osteoblasts in culture. The promising results with citric acid raised the suspicion that tetracycline could elicit similar effects. Thus, the aim of this study was to comparatively evaluate the behavior of pre-osteoblastic MC3T3-E1 cultured on bone surfaces of rat calvaria demineralized with tetracycline (50mg / ml) and citric acid (10%, pH1) at different times of application. 126 bicortical samples were removed from the calvarial bone of 63 adult male Wistar rats using trephine drill of 5 mm in diameter. Samples were randomly assigned to one of the following study groups (n = 18) AC 15 in which the samples were demineralized by citric acid for 15 seconds; AC 30, in which the samples were demineralized by citric acid for 30 seconds; AC 60 wherein the samples were demineralized by citric acid for 60 seconds; TCN 15 in which the samples were demineralized tetracycline for 15 seconds; TCN 30, in which the samples were demineralized tetracycline for 30 seconds; TCN 60 wherein the samples were demineralized tetracycline for 60 seconds, and C, control group of samples not demineralized. The pre-osteoblasts were cultured on the samples for 24, 48 and 72 hours (n = 6) to be examined in the scanning electron microscope. Twenty-one samples were collected from other 11 animals and were distributed among the same groups for analysis of the surface chemical composition by energy dispersive spectroscopy (EDS) (n = 3). The average percentage of the bone surfaces covered by cells was significantly higher after 24 and 48 hours of culture in groups AC15 (60.38% and 100% respectively), AC30 (99.32% and 100% respectively), AC60 (99.22% and 100% respectively) TCN15 (96.73% and 70.24% respectively) and TCN30 (64.72% and 57.40% respectively) than in groups TCN60 (9.67% and 51.45% respectively), and C (5.99% and 31.83% respectively). At 72 hours, all the groups presented almost complete covering of the surfaces by cells, with the exception of TCN60 group (56.15%). Cells presented with morphology compatible with more advanced stages of differentiation in groups undergone to demineralization than control. Variations in the anatomical percentages (A%) of the elements C, O, Na, Mg, Ca and P were insufficient to justify changes in cell behavior. The conclusion was that both demineralization of citric acid or tetracycline are favorable for the growth and differentiation of pre-osteoblasts especially when used according to AC30 and TCN15 groups. The mechanisms behind these results still need elucidation.

Typescript (photocopy)

One of the most elusive challenges in the diagnosis and treatment of dysphagia is the reliable identification of silent aspiration (aspiration in the absence of cough). The citric acid inhalation cough challenge offers potential for aiding in identification of silent aspiration; however clinical application of this technique is currently problematic due to an absence of normative data. Therefore, this study aimed to establish a normative data set for the Citric- Acid Inhalation Cough Challenge, as administered with facemask method. 80 healthy subjects will participate in this study, constituting 2 age groups: above and below 60 years, with equal gender representation. On 3 separate trials, they will be asked to passively inhale, via a facemask, nebulised citric acid of concentrations ranging from 08M to 2.6M with placebo interspersed. ‘Natural cough thresholds’ (NCT) and ‘Suppressed Cough Thresholds’ (SCT) will be reached when subjects cough on at least 2 out of 3 trials. The majority (92.5%) of participants reached Natural Cough Threshold by 0.8M, with 68% demonstrating Suppressed Cough Threshold also at this concentration. There were no significant differences found between males and females (p<0.05) for either NCT (p=0.9885) or SCT (p=0.44). Whilst no difference was found between youngers and elders for NCT (p=0.7254), there was a significant difference for SCT (p=0.018), with youngers better able to suppress cough. Over 90% of healthy people were found to elicit cough at 0.8M, inferring that this level would be an adequate guide for use by clinicians testing for presence/absence of cough.