Composition of dental plaque formed in the presence of sucrose and after its interruption

Since dental plaque reservoirs of fluoride (F), calcium (Ca) and inorganic phosphorus (Pi) are susceptible to decreases in pH, this in situ crossover study was conducted to test the hypothesis that the low concentration of these ions in plaque, formed in the presence of sucrose, could be attributed merely to the fermentation of this sugar. Eleven volunteers wore palatal appliances containing 6 human enamel blocks during two stages. In each stage, the treatments were either 20% sucrose solution or distilled deionized water, which were dripped onto the blocks 8 times a day. After 28 days, in each stage, the dental plaque formed on two blocks was collected, the treatment was inverted and after a further 24 and 48 h, the biofilm formed was collected from the other blocks. The concentration of acid-soluble F, Ca and Pi, and the concentration of insoluble polysaccharide (IP) were determined in the dental plaque. Statistically lower concentrations of F, Ca and Pi, and a higher concentration of IP were found in the 28-day biofilm formed in the presence of sucrose than in its absence; after the treatment inversion the change in F, Ca and Pi was not statistically significant, but the IP concentration changed significantly. The hypothesis was rejected because change in concentration of F, Ca and Pi is not due to fermentation of the sucrose

Composition of dental plaque formed in the presence of sucrose and after its interruption

Since dental plaque reservoirs of fluoride (F), calcium (Ca) and inorganic phosphorus (Pi) are susceptible to decreases in pH, this in situ crossover study was conducted to test the hypothesis that the low concentration of these ions in plaque, formed in the presence of sucrose, could be attributed merely to the fermentation of this sugar. Eleven volunteers wore palatal appliances containing 6 human enamel blocks during two stages. In each stage, the treatments were either 20% sucrose solution or distilled deionized water, which were dripped onto the blocks 8 times a day. After 28 days, in each stage, the dental plaque formed on two blocks was collected, the treatment was inverted and after a further 24 and 48 h, the biofilm formed was collected from the other blocks. The concentration of acid-soluble F, Ca and Pi, and the concentration of insoluble polysaccharide (IP) were determined in the dental plaque. Statistically lower concentrations of F, Ca and Pi, and a higher concentration of IP were found in the 28-day biofilm formed in the presence of sucrose than in its absence; after the treatment inversion the change in F, Ca and Pi was not statistically significant, but the IP concentration changed significantly. The hypothesis was rejected because change in concentration of F, Ca and Pi is not due to fermentation of the sucrose.Desde que os reservatórios de flúor (F), cálcio (Ca) e fósforo inorgânico (Pi) na placa dental são suscetíveis a quedas de pH, este estudo in situ cruzado foi conduzido para testar a hipótese de que baixas concentrações destes íons na placa, formada na presença de sacarose, poderiam ser atribuídas simplesmente à fermentação deste açúcar. Onze voluntários utilizaram dispositivos palatinos contendo seis blocos de esmalte dental humano durante duas fases. Em cada fase os tratamentos foram solução de sacarose a 20% ou água destilada deionizada, que foram gotejadas sobre os blocos 8 vezes ao dia. Após 28 dias, em cada fase, a placa dental formada sobre dois blocos foi coletada, o tratamento foi invertido e após um tempo adicional de 24 e 48 horas, o biofilme formado foi coletado dos outros blocos. A concentração de F, Ca e Pi solúvel em ácido e a concentração de polissacarídeo insolúvel (PI) foram determinadas na placa dental. Concentrações estatisticamente menores de F, Ca e Pi, e uma concentração maior de PI foram encontradas no biofilme de 28 dias formado na presença de sacarose do que na sua ausência; após a inversão do tratamento a mudança no F, Ca e Pi não foi estatisticamente significante, mas a concentração de PI mudou significativamente. A hipótese foi rejeitada porque a mudança na concentração de F, Ca e Pi não é devida à fermentação da sacarose.147152Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Composition of dental plaque formed in the presence of sucrose and after its interruption

Since dental plaque reservoirs of fluoride (F), calcium (Ca) and inorganic phosphorus (Pi) are susceptible to decreases in pH, this in situ crossover study was conducted to test the hypothesis that the low concentration of these ions in plaque, formed in the presence of sucrose, could be attributed merely to the fermentation of this sugar. Eleven volunteers wore palatal appliances containing 6 human enamel blocks during two stages. In each stage, the treatments were either 20% sucrose solution or distilled deionized water, which were dripped onto the blocks 8 times a day. After 28 days, in each stage, the dental plaque formed on two blocks was collected, the treatment was inverted and after a further 24 and 48 h, the biofilm formed was collected from the other blocks. The concentration of acid-soluble F, Ca and Pi, and the concentration of insoluble polysaccharide (IP) were determined in the dental plaque. Statistically lower concentrations of F, Ca and Pi, and a higher concentration of IP were found in the 28-day biofilm formed in the presence of sucrose than in its absence; after the treatment inversion the change in F, Ca and Pi was not statistically significant, but the IP concentration changed significantly. The hypothesis was rejected because change in concentration of F, Ca and Pi is not due to fermentation of the sucrose

Núcleos de Ensino da Unesp: artigos 2013: volume 2: metodologias de ensino e a apropriação de conhecimento pelos alunos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Núcleos de Ensino da Unesp: artigos 2013: volume 2: metodologias de ensino e a apropriação de conhecimento pelos alunos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

The risk of COVID-19 death is much greater and age dependent with type I IFN autoantibodies

International audienceSignificance There is growing evidence that preexisting autoantibodies neutralizing type I interferons (IFNs) are strong determinants of life-threatening COVID-19 pneumonia. It is important to estimate their quantitative impact on COVID-19 mortality upon SARS-CoV-2 infection, by age and sex, as both the prevalence of these autoantibodies and the risk of COVID-19 death increase with age and are higher in men. Using an unvaccinated sample of 1,261 deceased patients and 34,159 individuals from the general population, we found that autoantibodies against type I IFNs strongly increased the SARS-CoV-2 infection fatality rate at all ages, in both men and women. Autoantibodies against type I IFNs are strong and common predictors of life-threatening COVID-19. Testing for these autoantibodies should be considered in the general population

The risk of COVID-19 death is much greater and age dependent with type I IFN autoantibodies

International audienceSignificance There is growing evidence that preexisting autoantibodies neutralizing type I interferons (IFNs) are strong determinants of life-threatening COVID-19 pneumonia. It is important to estimate their quantitative impact on COVID-19 mortality upon SARS-CoV-2 infection, by age and sex, as both the prevalence of these autoantibodies and the risk of COVID-19 death increase with age and are higher in men. Using an unvaccinated sample of 1,261 deceased patients and 34,159 individuals from the general population, we found that autoantibodies against type I IFNs strongly increased the SARS-CoV-2 infection fatality rate at all ages, in both men and women. Autoantibodies against type I IFNs are strong and common predictors of life-threatening COVID-19. Testing for these autoantibodies should be considered in the general population