Steviol effect, a glycoside of Stevia rebaudiana, on glucose clearances in rats

Stevia rebaudiana, a South American plant normally used as a natural herbal sweetener, has been suggested as exerting beneficial effects on human health, including as an antihypertensive and antihyperglycemic. The present experiment was undertaken to evaluate the renal excretion of steviol, the aglycone of several natural products extracted from the leaves of S. rebaudiana, and to clarify the actual participation of this compound on the renal excretion of glucose in rats, which has been previously suggested as the preferential action of steviol on the Na+-glucose renal tubular transport system. Steviol was obtained by enzymatic hydrolysis of stevioside with pectinase. Thirty normal male Wistar rats weighing 345 g were used. After a control period, steviol was infused iv at three doses (0.5, 1.0 and 3.0 mg.kg-1/h), according to classical clearance techniques. During all the experiments no significant changes in inulin clearance (Cin) and p-aminohipuric acid clearance (C PAH) were observed. Administration of steviol resulted in a statistically significant increase in the fractional sodium excretion (FeNa+), fractional potassium excretion (FeK+), urinary flow as percent of glomerular filtration rate (V/GFR) and glucose clearance (C G) when compared to controls, but these effects were absent with the dose of 0.5 mg.kg-1/h. The steviol clearance (C S) was higher than the Cin and lower than the C PAH at all the doses employed in this study. The data suggest that steviol is secreted by renal tubular epithelium, causing diuresis, natriuresis, kaliuresis and a fall in renal tubular reabsorption of glucose.

The effect of using mixed initiator systems on the efficiency of photopolymerization of dental resins

A study was performed in order to determine the efficiency of the simultaneous use of the photoinitiators phenylpropanedione (PPD) and camphorquinone (CQ) in the polymerization of acrylic polymers and evaluate possible mechanisms leading to synergism or antagonism. It was found that efficiencies of both initiators taken individually are higher than that of their mixture, indicating that when both dyes are used simultaneously there will be an energy transfer from the more efficient initiator (CQ) to the less efficient one (PPD). Also, there was no proof of any reaction between the amine present in the CQ formulation and the PPD excited state.

Effect of temperature on the electro-oxidation of ethanol on platinum

We present in this work an experimental investigation of the effect of temperature (from 25 to 180 ºC) in the electro-oxidation of ethanol on platinum in two different phosphoric acid concentrations. We observed that the onset potential for ethanol electro-oxidation shifts to lower values and the reaction rates increase as temperature is increased for both electrolytes. The results were rationalized in terms of the effect of temperature on the adsorption of reaction intermediates, poisons, and anions. The formation of oxygenated species at high potentials, mainly in the more diluted electrolyte, also contributes to increase the electro-oxidation reaction rate.

Effect of experimental heat treatment on mechanical properties of resin composites

The aim of this study was to verify the influence of an experimental heat treatment (170ºC/10 min) using a casting furnace on the mechanical properties (hardness and flexural strength) of 2 commercial direct resin composites (TPH Spectrum and Filtek P60) compared to a commercial indirect resin system (BelleGlass). Heat treatment temperature was determined after thermal characterization by thermogravimetry (TG) and differential scanning calorimetry (DSC). Data was analyzed by ANOVA and Tukey's test at 5% significance level. There was statistical significance for the main factor heat treatment (p=0.03) and composite (p=0.02), for flexural strength. For Knoop hardness, only the main factor composite was statistically significant (p=0.00). P60 presented higher hardness than TPH. No statistically significant correlation between mechanical properties tested was detected. Based on these results, it was possible to conclude that heat treatment influenced flexural strength of direct composites, while it was not observed for hardness. The association of direct composites with a simple post-cure heat treatment may be an alternative for current indirect composite systems, although more studies are needed to verify other properties of the composites for this application.

Effect of cold fronts on the benthic macrofauna of exposed sandy beaches with contrasting morphodynamics

The aim of this study was to determine the short-term environmental changes caused by the simultaneous passage of a high energy event on two sandy beaches with different morphodynamic states and their influence on the richness, abundance and distribution of the benthic macrofauna. Two microtidal exposed sandy beaches with contrasting morphodynamics were simultaneously sampled before, during and after the passage of two cold fronts in Santa Catarina. The reflective beach showed a higher susceptibility to the increase in wave energy produced by the passage of cold fronts and was characterized by rapid and intense erosive processes in addition to a capacity for rapid restoration of the beach profile. As regards the dissipative beach, erosive processes operated more slowly and progressively, and it was characterized further by a reduced capacity for the recovery of its sub-aerial profile. Although the intensity of the environmental changes was distinct as between the morphodynamic extremes, changes in the composition, richness and abundance of macrobenthos induced by cold fronts were not evident for either of the beaches studied. On the other hand, alterations in the distribution pattern of the macrofauna were observed on the two beaches and were related to variations in sea level, position of the swash zone and moisture gradient, suggesting that short-term accommodations in the spatial structure of the macrobenthos occur in response to changes in environmental conditions in accordance with the temporal dynamics characteristic of each morphodynamic state.

Effect of morphodynamics on annual average zonation pattern of benthic macrofauna of exposed sandy beaches in Santa Catarina, Brazil

This study investigated the effect of environmental factors on the annual average zonation pattern of benthic macrofauna of sub-aerial profile of three exposed sandy beaches of Santa Catarina with different morphodynamic characteristics. Sampling was carried out between March 2000 and March 2001, with monthly frequency on reflective and dissipative morphodynamic extremes and bimonthly frequency on the intermediate state. Results showed that macrobenthic zonation presented marked differences across the morphodynamic spectrum. The main differences observed from reflective to dissipative conditions were: a) increase in the number of species in lower zones of the beach; b) expansion of zones characterized by high water content of sediment and c) increase in the overlapping of zones, mainly on lower levels of the beach. Canonical Correspondence Analysis related these differences to distinctive cross-shore gradients in sediment moisture levels, sediment reworking and mean grain size that exist across the morphodynamic spectrum, showing that it is important to analyze these environmental factors in studies conducted to investigate zonation on microtidal exposed sandy beaches.

Effect of CO2 and 1-octen-3-ol attractants for estimating species richness and the abundance of diurnal mosquitoes in the southeastern Atlantic forest, Brazil

Studies have shown that both carbon dioxide (CO2) and octenol (1-octen-3-ol) are effective attractants for mosquitoes. The objective of the present study was to evaluate the attractiveness of 1-octen-3-ol and CO2 for diurnal mosquitoes in the southeastern Atlantic forest. A Latin square experimental design was employed with four treatments: CDC-light trap (CDC-LT), CDC-LT and 1-octen-3-ol, CDC-LT and CO2 and CDC-LT with 1-octen-3-ol and CO2. Results demonstrated that both CDC-CO2 and CDC-CO2-1-octen-3-ol captured a greater number of mosquito species and specimens compared to CDC-1-octen-3-ol; CDC-LT was used as the control. Interestingly, Anopheles (Kerteszia) sp. was generally attracted to 1-octen-3-ol, whereas Aedes serratus was the most abundant species in all Latin square collections. This species was recently shown to be competent to transmit the yellow fever virus and may therefore play a role as a disease vector in rural areas of Brazil.

Efetividade de programa de suplementação alimentar no ganho ponderal de crianças

OBJETIVO: Avaliar a efetividade de programa governamental de suplementação alimentar no ganho ponderal de crianças. MÉTODOS: Estudo de coorte com dados secundários de 25.433 crianças de baixa renda com idade entre seis e 24 meses que ingressaram em programa de distribuição de leite fortificado Projeto Vivaleite, realizado no Estado de São Paulo de 2003 a 2008. O ganho ponderal foi medido por meio dos valores de escores z de peso para idade, calculados pelo padrão da Organização Mundial da Saúde (2007), obtidos, na rotina do programa, ao ingressar e a cada quatro meses durante a permanência. As crianças foram divididas em três grupos de escore z ao entrar: sem comprometimento de peso (z > -1); risco de baixo peso (-2 < z < -1) e baixo peso (z < -2). Utilizou-se regressão linear multinível (modelo misto), permitindo a comparação, em cada idade, das médias ajustadas do escore z dos ingressantes e participantes há pelo menos quatro meses, ajustadas para correlação entre medidas repetidas. RESULTADOS: Verificou-se efeito positivo do programa no ganho de peso das crianças, variando em função do estado nutricional ao ingressar; para as que entraram sem comprometimento de peso, o ganho médio ajustado foi 0,183 escore z;entre as que entraram com risco de baixo peso, foi 0,566; e entre as ingressantes com baixo peso, foi 1,005 escore z. CONCLUSÕES: O programa é efetivo para o ganho ponderal de crianças menores de dois anos, com efeito mais pronunciado entre as crianças que entram no programa em condições menos favoráveis de peso.

Assessing the validity of a food frequency questionnaire among low-income women in São Paulo, southeastern Brazil

This study describes the validity of a food frequency questionnaire (FFQ) in 93 low-income women (20-65 years), participating in a case-control study in São Paulo, Brazil. Two FFQ (FFQ1 and FFQ2, 12 months apart) and three 24-hour dietary recalls (24hR) were conducted between 2003 and 2004 to estimate dietary intake during the past year. The Pearson correlation coefficients (crude, energy-adjusted and de-attenuated) were used for comparisons between FFQ and 24hR. The agreement between the methods was further examined by the Bland-Altman analysis. For the assessment of long-term reliability, the energy-adjusted intra-class correlation coefficients were mostly around 0.40, but higher for vitamin A and folate (0.50-0.56). Energy-adjusted, attenuation-corrected Pearson validity correlations between FFQ and DR ranged from 0.30-0.54 for macronutrients to 0.20-0.48 for micronutrients, with higher value for calcium (0.75). There were small proportions of grossly misclassified nutrient intakes, while Bland-Altman plots indicated that the FFQ is accurate in assessing nutrient intake at a group level.

Influência da mídia em universitárias brasileiras de diferentes regiões

A mídia tem impacto na satisfação com a imagem corporal e risco para o desenvolvimento de transtornos alimentares. OBJETIVO: Avaliar a influência da mídia em universitárias e possíveis associações com idade, estado nutricional, renda e escolaridade do chefe da família. MÉTODOS: 2.489 estudantes do sexo feminino das cinco regiões do Brasil responderam à Sociocultural Attitudes Towards Appearance Scale (SATAQ-3). O escore na SATAQ foi comparado entre as regiões por meio de uma análise de variância. Uma análise de covariância foi utilizada para verificar a influência das variáveis estudadas no escore da SATAQ. Uma regressão logística foi realizada para verificar a interferência conjunta das variáveis em relação à influência da mídia. RESULTADOS: Não foram encontradas diferenças regionais na SATAQ total (p = 0,164) e subescalas Internalização atlética (p = 0,293) e Pressão (p = 0,150); houve diferença para as subescalas Internalização geral (p = 0,010) e Informação (p = 0,002). Idade, estado nutricional e renda influenciaram o resultado. CONCLUSÕES: O escore total na SATAQ foi similar entre as regiões, mas o Sul e o Nordeste apresentaram maiores pontuações para subescalas Internalização geral e Informação respectivamente. Estudantes com menos de 25 anos, com excesso de peso e maior renda foram em média mais influenciadas pela mídia.

Calibration of the dietary data obtained from the Brazilian center of the Natural History of HPV Infection in Men study: the HIM Study

The objective of this study was to estimate the regressions calibration for the dietary data that were measured using the quantitative food frequency questionnaire (QFFQ) in the Natural History of HPV Infection in Men: the HIM Study in Brazil. A sample of 98 individuals from the HIM study answered one QFFQ and three 24-hour recalls (24HR) at interviews. The calibration was performed using linear regression analysis in which the 24HR was the dependent variable and the QFFQ was the independent variable. Age, body mass index, physical activity, income and schooling were used as adjustment variables in the models. The geometric means between the 24HR and the calibration-corrected QFFQ were statistically equal. The dispersion graphs between the instruments demonstrate increased correlation after making the correction, although there is greater dispersion of the points with worse explanatory power of the models. Identification of the regressions calibration for the dietary data of the HIM study will make it possible to estimate the effect of the diet on HPV infection, corrected for the measurement error of the QFFQ.

Desigualdades no uso e acesso aos serviços de saúde entre idosos do município de São Paulo

OBJETIVO: Analisar os fatores relacionados à determinação e às desigualdades no acesso e uso dos serviços de saúde por idosos. MÉTODOS: Estudo integrante do Projeto Saúde, Bem-estar e Envelhecimento (SABE), no qual foram entrevistados 2.143 indivíduos com 60 anos ou mais no município de São Paulo, SP, em 2000. A amostra foi obtida em dois estágios, utilizando-se setores censitários com reposição, probabilidade proporcional à população e complementação da amostra de pessoas de 75 anos. Foi mensurado o uso de serviços hospitalares e ambulatoriais nos quatro meses anteriores à entrevista, relacionando-os com fatores de capacidade, necessidade e predisposição (renda total, escolaridade, seguro saúde, morbidade referida, auto-percepção, sexo e idade). O método estatístico utilizado foi regressão logística multivariada. RESULTADOS: Dos entrevistados, 4,7% referiram ter utilizado a internação hospitalar e 64,4% o atendimento ambulatorial. Dos atendimentos ambulatoriais em serviço público, 24,7% ocorreram em hospital e 24,1% em serviço ambulatorial; dentre os que ocorreram em serviços privados, 14,5% foram em hospital e 33,7% em clínicas. Pela análise multivariada, observou-se associação entre a utilização de serviços e sexo, presença de doenças, auto-percepção de saúde, interação da renda e escolaridade e posse de seguro saúde. A análise isolada com escolaridade apresentou efeito inverso. CONCLUSÕES: Foram observadas desigualdades no uso e acesso aos serviços de saúde e inadequação do modelo de atenção, indicando necessidade de políticas públicas que levem em conta as especificidades dessa população, facilitem o acesso e possam reduzir essas desigualdades.

Peso insuficiente ao nascer e crescimento alcançado na idade pré-escolar, por crianças atendidas em creches filantrópicas do município de Santo André, São Paulo, Brasil

OBJETIVOS: comparar o crescimento alcançado e a prevalência de baixa estatura na idade pré-escolar entre recém-nascidos de peso insuficiente (PNI) e de peso adequado (PNA). MÉTODOS: foram estudadas 323 crianças com PNI e 886 com PNA de famílias de baixa renda de quinze creches filantrópicas de Santo André, São Paulo, Brasil, em 2001 e 2002. As variáveis foram o escore Z de peso e de estatura para a idade, pelo referencial Center for Disease Control (CDC) and National Center for Health Statistics (NCHS) 2000, comparando-se as médias dos dois grupos. Calculou-se a razão de prevalência (RP) de baixa estatura na idade pré-escolar em decorrência do peso insuficiente ao nascer. RESULTADOS: o escore z médio de peso foi -0,09 e 0,39 e o escore z médio de estatura foi de -0,06 e de 0,24 para as crianças de PNI e de PNA, respectivamente. A prevalência de baixa estatura foi de 2,78% para as crianças com PNI e de 0,79% para aquelas com PNA. A RP de baixa estatura na idade pré-escolar para as crianças de PNI foi de 3,5 (IC95% 1,3-9,4). CONCLUSÕES: as crianças com PNI apresentaram crescimento inferior e maior risco de falhas de crescimento até a idade pré-escolar, sugerindo um efeito negativo do peso insuficiente ao nascer sobre o crescimento infantil.

Effect of an energy-deficient diet on populations of ciliate protozoans in bovine rumen

Ten young rumen-cannulated crossbred steers were randomly divided into two groups: a control group (C; n=4), which was fed a balanced diet for daily weight gain of 900g; and a pronounced energy-deprived group (PED; n=6), receiving 30% less of the required energy for maintenance. After 140 days of these alimentary regimes, rumen fluid and urine samples were collected for biochemical and functional tests, before feeding and at 1, 3, 6, and 9 hours after feeding. The energy-deprivation diet caused a significant reduction in the number of Entodinium, Eodinium, Isotricha, Dasytricha, Eremoplastron, Eudiplodinium, Metadinium, Charonina, Ostracodinium, and Epidinium protozoa. There was no effect of the time of sampling in both groups on the total number of ciliates in rumen fluid. A higher number of protozoan forms in binary division were recorded in the control group, at the 6th and 9th hours after feeding (P<0.019). There was a high positive correlation between the total count of protozoans in rumen fluid and glucose fermentation, ammonia, and urinary allantoin excretion index; and a negative correlation between the total count of protozoa and metilene blue reduction, and a medium correlation between the total count of protozoa and total volatile fatty acids concentration. The determination of the protozoa populations does not imply in the use of complex and hard-to-execute techniques, although it is time consuming and needs practice. This exam particularly helps in clinical expected diagnosis.

Effect of the kappa-casein gene polymorphism, breed and seasonality on physicochemical characteristics, composition and stability of bovine milk

The objective of this study was to evaluate the effect of genetic polymorphism of kappa-casein, breed and seasonality on the physicochemical characteristics, composition and stability of milk in commercial dairy herds. A total of 879 milk and blood samples were collected from 603 Holstein and 276 Girolando cows, obtained during rainy and dry seasons. Milk samples were analyzed to determine the physicochemical characteristics, composition and ethanol stability, while blood samples were subjected to polymerase chain reaction to identify the kappa-casein genotype. The frequencies of genotypes AA, AB and BB of k-casein were respectively, 66.83, 31.84 and 1.33% for Holstein, and 71.38, 27.90 and 0.72% for the Girolando cows, respectively. The A allele was more frequent than the B allele, both for Holstein (0.827 and 0.173) and Girolando cows (0.853 and 0.147), respectively. Cows of AB and BB genotypes showed a higher milk fat content compared to the AA genotype. There was an interaction between breed and seasonality on the concentration of milk urea with higher values for Holstein and Girolando cows in the rainy and dry season, respectively. The levels of lactose, total solids, crude protein, true protein, casein and the casein:true protein ratio were higher during the dry season, while during the rainy season, the somatic cell count and milk urea concentration were higher. There was no association between milk stability and k-casein genotypes, but Holstein cows showed higher milk stability than Girolando cows, and milk was more stable during the rainy season than during the dry season.