998 resultados para Manuel Pereira Medeiros (1936-2013)
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Background: The purpose of this study was to estimate the genetic influences on the initiation of cigarette smoking, the persistence, quantity and age-at-onset of regular cigarette use in Brazilian families. Methods: The data set consisted of 1,694 individuals enrolled in the Baependi Heart Study. The heritability and the heterogeneity in genetic and environmental variance components by gender were estimated from variance components approaches, using the SOLAR (Sequential Oligogenic Linkage Analysis Routines) computer package. The mixed-effects Cox model was used for the genetic analysis of the age-at onset of regular cigarette use. Results: The heritability estimates were high (> 50%) for smoking initiation and were intermediate, ranging from 23.4 to 31.9%, for smoking persistence and quantity. Significant evidence for heterogeneity in variance components by gender was observed for smoking initiation and age-at-onset of regular cigarette use. Genetic factors play an important role in the interindividual variation of these phenotypes in females, while in males there is a predominant environmental component, which could be explained by greater social influences in the initiation of tobacco use. Conclusions: Significant heritabilities were observed in smoking phenotypes for both males and females from the Brazilian population. These data add to the literature and are concordant with the notion of significant biological determination in smoking behavior. Samples from the Baependi Heart Study may be valuable for the mapping of genetic loci that modulate this complex biological trait.
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Background: Although acceptability of combined oral contraceptives (COCs) is widespread, patients are often unaware of the noncontraceptive benefits. Study Design: An opinion survey through telephone interview was conducted to evaluate the knowledge of 500 Brazilian women 15-45 years of age who were current users or had recently used COCs. Data were obtained on their knowledge of adverse events, the effects of COCs on health- and menstrual-related symptoms, noncontraceptive benefits and aspects related to sexual response. Results: Most of the women interviewed learned about the pill from doctors or the Internet. Other than the pill, the best-known contraceptive methods were the condom and intrauterine device. The majority of women believe that COCs do not change the risk of gynecological cancers. Most believed that they had no significant effect on sexual response. Conclusions: COCs users in Brazil lack precise information on aspects related to general health, particularly menstrual-related symptoms and noncontraceptive health benefits. (C) 2012 Elsevier Inc. All rights reserved.
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Background: Warfarin-dosing pharmacogenetic algorithms have presented different performances across ethnicities, and the impact in admixed populations is not fully known. Aims: To evaluate the CYP2C9 and VKORC1 polymorphisms and warfarin-predicted metabolic phenotypes according to both self-declared ethnicity and genetic ancestry in a Brazilian general population plus Amerindian groups. Methods: Two hundred twenty-two Amerindians (Tupinikin and Guarani) were enrolled and 1038 individuals from the Brazilian general population who were self-declared as White, Intermediate (Brown, Pardo in Portuguese), or Black. Samples of 274 Brazilian subjects from Sao Paulo were analyzed for genetic ancestry using an Affymetrix 6.0 (R) genotyping platform. The CYP2C9*2 (rs1799853), CYP2C9*3 (rs1057910), and VKORC1 g.-1639G>A (rs9923231) polymorphisms were genotyped in all studied individuals. Results: The allelic frequency for the VKORC1 polymorphism was differently distributed according to self-declared ethnicity: White (50.5%), Intermediate (46.0%), Black (39.3%), Tupinikin (40.1%), and Guarani (37.3%) (p < 0.001), respectively. The frequency of intermediate plus poor metabolizers (IM + PM) was higher in White (28.3%) than in Intermediate (22.7%), Black (20.5%), Tupinikin (12.9%), and Guarani (5.3%), (p < 0.001). For the samples with determined ancestry, subjects carrying the GG genotype for the VKORC1 had higher African ancestry and lower European ancestry (0.14 +/- 0.02 and 0.62 +/- 0.02) than in subjects carrying AA (0.05 +/- 0.01 and 0.73 +/- 0.03) (p = 0.009 and 0.03, respectively). Subjects classified as IM + PM had lower African ancestry (0.08 +/- 0.01) than extensive metabolizers (0.12 +/- 0.01) (p = 0.02). Conclusions: The CYP2C9 and VKORC1 polymorphisms are differently distributed according to self-declared ethnicity or genetic ancestry in the Brazilian general population plus Amerindians. This information is an initial step toward clinical pharmacogenetic implementation, and it could be very useful in strategic planning aiming at an individual therapeutic approach and an adverse drug effect profile prediction in an admixed population.
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OBJECTIVE: To assess the prevalence of acute bronchitis, rhinitis, and sinusitis among children and adolescents and identify associated factors. METHODS: This is a population-based, cross-sectional study. A household survey was conducted with 1,185 children and adolescents from the city of Sao Paulo (Southeastern Brazil), from 2008 to 2009. The participants were selected by means of probability sampling, stratified by sex and age, and by two-stage cluster sampling. For the adjusted analysis, multiple Poisson regression was used. RESULTS: Of the respondents, 7.3% reported acute bronchitis, 22.6% rhinitis and 15.3% sinusitis. After the adjusted analysis, the following characteristics were associated with self;reported acute bronchitis: age 0 to 4 years (PR=17.86; 95%Cl: 3.65;90.91), 5 to 9 years (PR=37.04; 95%CI: 8.13;166.67), 10 to 14 years (PR.=20,83; 95%Cl: 4.93;90.91), allergy (PR=3.12; 95%Cl: 1.70;5.73), black and mixed-ethnicity (black and white) skin color (PR=2.29; 95%Cl: 1.21;4.35), and living in a household with 1 to 3 rooms (PR=1.85; 95%Cl: 1.17;2.94). As to self-reported rhinitis, the following characteristics were associated: age 10 to 14 years (PR=2.77; 95%Cl: 1.60;4.78), 15 to 19 years (P.R=2.58; 95%Cl: 1.52;4.39), allergy (PR=4.32; 95%Cl: 2.79;6.70), asthma (PR=2.30; 95%CI: 1.30;4.10) and living in flats (PR=1.70; 95%Cl: 1.06;2.73). Concerning self-reported sinusitis, the following characteristics were associated: age 5 to 9 years (PR=2.44; 95%Cl: 1.09;5.43), 10 to 14 years (PR=2.99; 95%CI: 1.36;6.58), 15 to 19 years (PR=3.62; 95%Cl: 1.68;7.81), allergy (PR=2.23 (95%CI: 1.41;3.52) and obesity (PR=4.42; 95%Cl: 1.56;12.50). CONCLUSIONS: Respiratory diseases were more prevalent in population groups with defined characteristics, such as age group, self-reported diseases, type of household and obesity.
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Objectives: To evaluate the effect of additives on the water sorption characteristics of Bis-GMA based copolymers and composites containing TEGDMA, CH(3)Bis-GMA or CF(3)Bis-GMA. Material and methods: Fifteen experimental copolymers and corresponding composites were prepared combining Bis-GMA and TEGDMA, CH(3)Bis-GMA or CF(3)Bis-GMA, with aldehyde or diketone (24 and 32 mol%) totaling 30 groups. For composites, barium aluminosilicate glass and pyrogenic silica was added to comonomer mixtures. Photopolymerization was effected by 0.2 wt% each of camphorquinone and N,N-dimethyl-p-toluidine. Specimen densities in dry and water saturated conditions were obtained by Archimedes' method. Water sorption and desorption were evaluated in a desorption-sorption-desorption cycle. Water uptake (%WU), water desorption (%WD), equilibrium solubility (ES; mu g/mm(3)), swelling (f) and volume increase (%V) were calculated using appropriate equations. Results: All resins with additives had increased %WU and ES. TEGDMA-containing systems presented higher %WU, %WD, ES, f and %V values, followed by resins based on CH(3)Bis-GMA and CF(3)Bis-GMA. Conclusions: Aldehyde and diketone led to increases in the water sorption characteristics of experimental resins.
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The electrochromic behavior of iron complexes derived from tetra-2-pyridyl-1,4-pyrazine (TPPZ) and a hexacyanoferrate species in polyelectrolytic multilayer adsorbed films is described for the first time. This complex macromolecule was deposited onto indium-tin oxide (ITO) substrates via self-assembly, and the morphology of the modified electrodes was studied using atomic force microscopy (AFM), which indicated that the hybrid film containing the polyelectrolyte multilayer and the iron complex was highly homogeneous and was approximately 50 nm thick. The modified electrodes exhibited excellent electrochromic behavior with both intense and persistent coloration as well as a chromatic contrast of approximately 70%. In addition, this system achieved high electrochromic efficiency (over 70 cm(2) C-1 at 630 nm) and a response time that could be measured in milliseconds. The electrode was cycled more than 10(3) times, indicating excellent stability.
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It is well known that crystals of topaz from the Eastern Brazilian Pegmatite Province may turn blue by the irradiation with Co-60 gamma rays followed by heat treatment. Also, it is known that the sensation of color changes with the thickness of these crystals. The dependence of the color, given by 1931 CIE chromaticity coordinates, with the thickness of the crystal was analyzed. The absorbance used in the calculation of these coordinates was given by the sum of Gaussian lines. The parameters of these lines were determined through the decomposition of the optical absorption spectra in the ultraviolet and visible regions. The decomposition revealed several lines, whose assignment was made considering studies in spodumene and beryl crystals and highly accurate quantum mechanical calculations. The transmittance becomes very narrow with increasing thickness, and the CIE chromaticity coordinates converge to the borderline of the CIE Chromaticity Diagram at the wavelength of maximum transmittance. Furthermore, the purity of color increases with increasing thickness, and the dominant wavelength reaches the wavelength of maximum transmittance.
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Background: A recent study investigated the MYLIP region in the Mexican population in order to fine-map the actual susceptibility variants of this locus. The p.N342S polymorphism was identified as the underlying functional variant accounting for one of the previous signals of genome-wide association studies and the N342 allele was associated with higher cholesterol concentrations in Mexican dyslipidemic individuals. To date, there is no further evaluation on this genotype-phenotype association in the literature. In this scenario, and because of a possible pharmacotherapeutic target of dyslipidemia, the main aim of this study was to assess the influence of the MYLIP p.N342S polymorphism on lipid profile in Brazilian individuals. Methods: 1295 subjects of the general population and 1425 consecutive patients submitted to coronary angiography were selected. General characteristics, biochemical tests, blood pressures, pulse wave velocity, and coronary artery disease scores were analyzed. Genotypes for the MYLIP rs9370867 (p.N342S, c.G1025A) polymorphism were detected by high resolution melting analysis. Results: No association of the MYLIP rs9370867 genotypes with lipid profile, hemodynamic data, and coronary angiographic data was found. Analysis stratified by hyperlipidemia, gender, and ethnicity was also performed and the sub-groups presented similar results. In both general population and patient samples, the MYLIP rs9370867 polymorphism was differently distributed according to ethnicity. In the general population, subjects carrying GG genotypes had higher systolic blood pressure (BP), diastolic BP, and mean BP values (129.0 +/- 23.3; 84.9 +/- 14.6; 99.5 +/- 16.8 mmHg) compared with subjects carrying AA genotypes (123.7 +/- 19.5; 81.6 +/- 11.8; 95.6 +/- 13.6 mmHg) (p = 0.01; p = 0.02; p = 0.01, respectively), even after adjustment for covariates. However, in analysis stratified by ethnicity, this finding was not found and there is no evidence that the polymorphism influences BP. Conclusion: Our findings indicate that association studies involving this MYLIP variant can present distinct results according to the studied population. In this moment, further studies are needed to reaffirm if the MYLIP p.N342S polymorphism is functional or not, and to identify other functional markers within this gene.
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In this paper, we investigate the behavior of a family of steady-state solutions of a nonlinear reaction diffusion equation when some reaction and potential terms are concentrated in a e-neighborhood of a portion G of the boundary. We assume that this e-neighborhood shrinks to G as the small parameter e goes to zero. Also, we suppose the upper boundary of this e-strip presents a highly oscillatory behavior. Our main goal here was to show that this family of solutions converges to the solutions of a limit problem, a nonlinear elliptic equation that captures the oscillatory behavior. Indeed, the reaction term and concentrating potential are transformed into a flux condition and a potential on G, which depends on the oscillating neighborhood. Copyright (C) 2012 John Wiley & Sons, Ltd.
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RNA interference (RNAi) is a natural endogenous process by which double-stranded RNA molecules trigger potent and specific gene silencing in eukaryotic cells and is characterized by target RNA cleavage. In mammals, small interfering RNAs (siRNAs) are the trigger molecules of choice and constitute a new class of RNA-based antiviral agents. In an efficient RNAi response, the antisense strand of siRNAs must enter the RNA-induced silencing complex (RISC) in a process mediated by thermodynamic features. In this report, we hypothesize that silent mutations capable of inverting thermodynamic properties can promote resistance to siRNAs. Extensive computational analyses were used to assess whether continuous selective pressure that promotes such mutations could lead to the emergence of viral strains completely resistant to RNAi (i.e., prone to transfer only the sense strands to RISC). Based on our findings, we propose that, although synonymous mutations may produce functional resistance, this strategy cannot be systematically adopted by viruses since the longest RNAi-refractory sequence is only 10 nt long. This finding also suggests that all mRNAs display fluctuating thermodynamic landscapes and that, in terms of thermodynamic features, RNAi is a very efficient antiviral system since there will always be sites susceptible to siRNAs.
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Background: Several models have been designed to predict survival of patients with heart failure. These, while available and widely used for both stratifying and deciding upon different treatment options on the individual level, have several limitations. Specifically, some clinical variables that may influence prognosis may have an influence that change over time. Statistical models that include such characteristic may help in evaluating prognosis. The aim of the present study was to analyze and quantify the impact of modeling heart failure survival allowing for covariates with time-varying effects known to be independent predictors of overall mortality in this clinical setting. Methodology: Survival data from an inception cohort of five hundred patients diagnosed with heart failure functional class III and IV between 2002 and 2004 and followed-up to 2006 were analyzed by using the proportional hazards Cox model and variations of the Cox's model and also of the Aalen's additive model. Principal Findings: One-hundred and eighty eight (188) patients died during follow-up. For patients under study, age, serum sodium, hemoglobin, serum creatinine, and left ventricular ejection fraction were significantly associated with mortality. Evidence of time-varying effect was suggested for the last three. Both high hemoglobin and high LV ejection fraction were associated with a reduced risk of dying with a stronger initial effect. High creatinine, associated with an increased risk of dying, also presented an initial stronger effect. The impact of age and sodium were constant over time. Conclusions: The current study points to the importance of evaluating covariates with time-varying effects in heart failure models. The analysis performed suggests that variations of Cox and Aalen models constitute a valuable tool for identifying these variables. The implementation of covariates with time-varying effects into heart failure prognostication models may reduce bias and increase the specificity of such models.
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An overview is given of the limitations of Luttinger liquid theory in describing the real time equilibrium dynamics of critical one-dimensional systems with nonlinear dispersion relation. After exposing the singularities of perturbation theory in band curvature effects that break the Lorentz invariance of the Tomonaga-Luttinger model, the origin of high frequency oscillations in the long time behaviour of correlation functions is discussed. The notion that correlations decay exponentially at finite temperature is challenged by the effects of diffusion in the density-density correlation due to umklapp scattering in lattice models.
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Purpose Recent studies reported the association of SLCO1B1 haplotypes with the development of musculoskeletal side effects during simvastatin use. The aim was to evaluate the pharmacogenetic association of SLCO1B1 haplotypes with atorvastatin-induced myalgia in a sample of individuals on high-dose atorvastatin regimens. Methods One hundred and forty-three patients with familial hypercholesterolemia were followed for at least 12 months while receiving atorvastatin. Genotypes for the rs2306283 (c.A388G) and rs4149056 (c.T521C) polymorphisms were detected by high-resolution melting analysis. These markers form four distinct haplotypes (*1A, *1B, *5 and *15). Results During the follow-up period, 14 (9.8%) patients developed myalgia and 16 (11.2%) presented CK levels more than 3 times the upper limit of the normal range. No association of the SLCO1B1 rs2306283 and rs4149056 genotypes or haplotypes with the presence of myalgia or creatine kinase (CK) values was found. Presence of rs2306283 AG+GG genotypes was not associated with increased risks of myalgia or abnormal CK values (OR 2.08, 95% CI 0.62-7.00, p=0.24 and OR 0.51, 95% CI 0.21-1.26, p=0.15 respectively). The presence of rs4149056 TC+CC genotypes was also not associated with increased risk of myalgia or abnormal CK values (OR 2.24, 95% CI 0.47-10.72, p=0.31 and OR 1.51, 95% CI 0.57-3.96, p=0.41 respectively). Conclusions Our findings reaffirm that the SLCO1B1 genetic risk appears to be greater in those patients receiving simvastatin compared with those receiving atorvastatin. This suggests that the importance of SLCO1B1 haplotypes depends on the specific statin that has been used.
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Recent studies on the obligate interaction between fig trees and their pollinating agaonid wasps have focused on population aspects and wasp-seed exploitation at the level of the inflorescence. Detailed studies on larval and gall development are required to more fully understand how resources are exploited and adaptations fine-tuned by each partner in nursery pollination mutualisms. We studied the larval development of the active pollinating fig wasp, Pegoscapus sp., and the galling process of individual flowers within the figs of its monoecious host, Ficus citrifolia, in Brazil. The pollinator development is strongly dependent on flower pollination. Figs entered by pollen-free wasps were in general more likely to abort. Retained, unpollinated figs had both higher larval mortality and a lower number of wasps. Pegoscapus sp. larvae are adapted to plant development, with two contrasting larval feeding strategies proceeding alongside gall development. The first two larval stages behave as ovary parasites. Later larval stages feed on hypertrophied endosperm. This indicates that a successful galling process relies on endosperm, and also reveals why pollination would be a prerequisite for the production of high-quality galls for this Pegoscapus species.
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de Oliveira Alvim R, Lima Santos PCJ, Goncalves Dias R, Rodrigues MV, de Sa Cunha R, Mill JG, Junior WN, Krieger JE, Pereira AC. Association between the C242T polymorphism in the p22phox gene with arterial stiffness in the Brazilian population. Physiol Genomics 44: 587-592, 2012. First published April 10, 2012; doi:10.1152/physiolgenomics.00122.2011.-NADPH oxidase p22phox subunit is responsible for the production of reactive oxygen species in the vascular tissue. The C242T polymorphism in the p22phox gene has been associated with diverse coronary artery disease phenotypes, but the findings about the protective or harmful effects of the T allele are still controversial. Our main aim was to assess the effect of p22phox C242T genotypes on arterial stiffness, a predictor of late morbidity and mortality, in individuals from the general population. We randomly selected 1,178 individuals from the general population of Vitoria City, Brazil. Genotypes for the C242T polymorphism were detected by PCR-RFLP, and pulse wave velocity (PWV) values were measured with a noninvasive automatic device Complior. p22phox and TNF-alpha gene expression were quantified by real-time PCR in human arterial mammary smooth muscle cells. In both the entire and nonhypertensive groups: individuals carrying the TT genotype had higher PWV values and higher risk for increased arterial stiffness [odds ratio (OR) 1.93, 95% confidence interval (CI) 1.27-2.92 and OR 1.78, 95% CI 1.07-2.95, respectively] compared with individuals carrying CC + CT genotypes, even after adjustment for covariates. No difference in the p22phox gene expression according C242T genotypes was observed. However, TNF-alpha gene expression was higher in cells from individual carrying the T allele, suggesting that this genetic marker is associated with functional phenotypes at the gene expression level. In conclusion, we suggest that p22phox C242T polymorphism is associated with arterial stiffness evaluated by PWV in the general population. This genetic association shed light on the understanding of the genetic modulation on vascular dysfunction mediated by NADPH oxidase.