869 resultados para electroabsorption modulator (EAM)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Medicina Veterinária - FCAV
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Zootecnia - FCAV
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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We report on the generation of tunable light around 400 nm by frequency-doubling ultrashort laser pulses whose spectral phase is modulated by a sum of sinusoidal functions. The linewidth of the ultraviolet band produced is narrower than 1 nm, in contrast to the 12 nm linewidth of the non-modulated incident spectrum. The influence of pixellation of the liquid crystal spatial light modulator on the efficiency of the phase-modulated second harmonic generation is discussed.
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Objective: To investigate the relationship between TXNIP polymorphisms, diabetes and hypertension phenotypes in the Brazilian general population. Methods: Five hundred seventy-six individuals randomly selected from the general urban population according to the MONICA-WHO project guidelines were phenotyped for cardiovascular risk factors. A second, independent, sample composed of 487 family-trios from a different site was also selected. Nine TXNIP polymorphisms were studied. The potential association between TXNIP variability and glucose-phenotypes in children was also explored. TXNIP expression was quantified by real-time PCR in 53 samples from human smooth muscle cells primary culture. Results: TXNIP rs7211 and rs7212 polymorphisms were significantly associated with glucose and blood pressure related phenotypes. In multivariate logistic regression models the studied markers remained associated with diabetes even after adjustment for covariates. TXNIP rs7211 T/rs7212 G haplotype (present in approximately 17% of individuals) was significantly associated to diabetes in both samples. In children, the TXNIP rs7211 T/rs7212 G haplotype was associated with fasting insulin concentrations. Finally, cells harboring TXNIP rs7212 G allele presented higher TXNIP expression levels compared with carriers of TXNIP rs7212 CC genotype (p = 0.02). Conclusion: Carriers of TXNIP genetic variants presented higher TXNIP expression, early signs of glucose homeostasis derangement and increased susceptibility to chronic metabolic conditions such as diabetes and hypertension. Our data suggest that genetic variation in the TXNIP gene may act as a "common ground" modulator of both traits: diabetes and hypertension. (C) 2011 Elsevier Ireland Ltd. All rights reserved.
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Some mechanisms have been proposed to explain the role of bradykinin on glucose homeostasis and some studies reported that the BDKRB2 +9/-9 polymorphism was associated to the transcriptional activity of the receptor. In this scenario, the main aim of this study was to evaluate the association of the BDKRB2 +9/-9 polymorphism with diabetes mellitus risk in the Brazilian general population. This study included 1,032 subjects of the general urban population. Anthropometrical, blood pressure, biochemical, and genotype analyses for the BDKRB2 +9/-9 bp insertion/deletion polymorphism were performed. Individuals carrying +9/+9 or +9/-9 genotypes had higher glucose values (84.5 mg/dL versus 80.6 mg/dL, resp.) and higher frequency of diabetes mellitus (7.6% versus 3.6%, resp.) compared to individuals carrying -9/-9, adjusting for age and gender. In addition, higher diabetes mellitus risk was associated to presence of the +9/+9 or +9/-9 genotypes (OR = 1.91; 95% CI = 1.09-4.19; P = 0.03). Our data suggest that the BDKRB2 +9/-9 polymorphism may act as a genetic modulator of glucose homeostasis. It was previously associated to insulin sensitivity, glucose uptake, and insulin secretion, and, in this study, data suggest that the polymorphism may increase susceptibility to chronic metabolic conditions such as diabetes in the Brazilian population.
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Tamoxifen, a selective estrogen receptor modulator, has antifibrotic properties; however, whether it can attenuate renal fibrosis is unknown. In this study, we tested the effects of tamoxifen in a model of hypertensive nephrosclerosis (chronic inhibition of nitric oxide synthesis with L-NAME). After 30 days, treated rats had significantly lower levels of albuminuria as well as lower histologic scores for glomerulosclerosis and interstitial fibrosis than untreated controls. Tamoxifen was renoprotective despite having no effect on the sustained, severe hypertension induced by L-NAME. Tamoxifen prevented the accumulation of extracellular matrix by decreasing the expression of collagen I, collagen III, and fibronectin mRNA and protein. These renoprotective effects associated with inhibition of TGF-beta 1 and plasminogen activator inhibitor-1, and with a significant reduction in a-smooth muscle actin-positive cells in the renal interstitium. Furthermore, tamoxifen abrogated IL-1 beta- and angiotensin-II-induced proliferation of fibroblasts from both kidney explants and from the NRK-49F cell line. Tamoxifen also inhibited the expression of extracellular matrix components and the production and release of TGF-beta 1 into the supernatant of these cells. In summary, tamoxifen exhibits antifibrotic effects in the L-NAME model of hypertensive nephrosclerosis, likely through the inhibition of TGF-beta 1, suggesting that it may have therapeutic use in CKD treatment.
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Introduction: Human leukocyte antigen (HLA)-G is a nonclassic class I molecule that acts as a modulator of immune responses, and the expression of these molecules in virus-infected cells has been associated with subversion of the immune response. Objective: In this study, we performed a cross-sectional study, systematically comparing the expression of the HLA-G in benign, premalignant, and malignant oral lesions and correlating it with the presence of high-risk and low-risk human papillomavirus (HPV) types. Specimens and Methods: Oral biopsies were collected from 51 patients and analyzed by immunohistochemistry using anti HLA-G antibody. Human papillomavirus detection and typing from oral biopsies were obtained by polymerase chain reaction using GP5+/GP6+ and specific primers. Results: The 51 biopsies were stratified into 3 groups according to lesion grade: oral benign lesions (oral hyperplasia and papilloma, n = 16), oral premalignant lesions (oral leukoplakia with dysplasia and lichen planus, n = 17), and malignant lesions (oral squamous cell carcinoma, n = 18). Human leukocyte antigen G overexpression was mainly observed in benign and premalignant oral lesions but was not related to HPV infection (P>.05). On the other hand, HPV DNA was detected in 24 (47%) oral lesions, mainly in benign and premalignant lesions, with the most frequent type detected being high-risk HPV type. Conclusion: The HLA-G molecule was expressed in a significant number of benign oral lesions and was not correlated with HPV infection or oral cancer. Crown Copyright (C) 2012 Published by Elsevier Inc. All rights reserved.
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The 18 kDa translocator protein (TSPO) also known as the peripheral benzodiazepine receptor (PBR), mediates the transportation of cholesterol and anions from the outer to the inner mitochondrial membrane in different cells types. Although recent evidences indicate a potential role for TSPO in the development of inflammatory processes, the mechanisms involved have not been elucidated. The present study investigated the ability of the specific TSPO ligands, the isoquinoline carboxamide PK11195 and benzodiazepine Ro5-4864, on neutrophil recruitment promoted by the N-formylmethionyl-leucyl-phenylalanine peptide (fMLP), an agonist of G-protein coupled receptor (GPCR). Pre-treatment with Ro5-4864 abrograted fMLP-induced leukocyte-endothelial interactions in mesenteric postcapillary venules in vivo. Moreover, in vitro Ro5-4864 treatment prevented fMLP-induced: (i) L-selectin shedding and overexpression of PECAM-1 on the neutrophil cell surface; (ii) neutrophil chemotaxis and (iii) enhancement of intracellular calcium cations (iCa(+2)). Intriguingly, the two latter effects were augmented by cell treatment with PK11195. An allosteric agonist/antagonist relation may be suggested, as the effects of Ro5-4864 on fMLP-stimulated neutrophils were reverted by simultaneous treatment with PK11195. Taken together, these data highlight TSPO as a modulator of pathways of neutrophil adhesion and locomotion induced by GPCR, connecting TSPO actions and the onset of an innate inflammatory response. (C) 2011 Elsevier Inc. All rights reserved.
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Background: We investigated whether 9p21 polymorphisms are associated with cardiovascular events in a group of 611 patients enrolled in the Medical, Angioplasty or Surgery Study II (MASS II), a randomized trial comparing treatments for patients with coronary artery disease (CAD) and preserved left ventricular function. Methods: The participants of the MASS II were genotyped for 9p21 polymorphisms (rs10757274, rs2383206, rs10757278 and rs1333049). Survival curves were calculated with the Kaplan-Meier method and compared with the log-rank statistic. We assessed the relationship between baseline variables and the composite end-point of death, death from cardiac causes and myocardial infarction using a Cox proportional hazards survival model. Results: We observed significant differences between patients within each polymorphism genotype group for baseline characteristics. The frequency of diabetes was lower in patients carrying GG genotype for rs10757274, rs2383206 and rs10757278 (29.4%, 32.8%, 32.0%) compared to patients carrying AA or AG genotypes (49.1% and 39.2%, p = 0.01; 52.4% and 40.1%, p = 0.01; 47.8% and 37.9%, p = 0.04; respectively). Significant differences in genotype frequencies between double and triple vessel disease patients were observed for the rs10757274, rs10757278 and rs1333049. Finally, there was a higher incidence of overall mortality in patients with the GG genotype for rs2383206 compared to patients with AA and AG genotypes (19.5%, 11.9%, 11.0%, respectively; p = 0.04). Moreover, the rs2383206 was still significantly associated with a 1.75-fold increased risk of overall mortality (p = 0.02) even after adjustment of a Cox multivariate model for age, previous myocardial infarction, diabetes, smoking and type of coronary anatomy. Conclusions: Our data are in accordance to previous evidence that chromosome 9p21 genetic variation may constitute a genetic modulator in the cardiovascular system in different scenarios. In patients with established CAD, we observed an association between the rs2383206 and higher incidence of overall mortality and death from cardiac causes in patients with multi-vessel CAD.
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OBJECTIVE: Endostatin is a potent endogenous inhibitor of angiogenesis. It is derived from the proteolytic cleavage of collagen XVIII, which is encoded by the COL18A1 gene. A polymorphic COL18A1 allele encoding the functional polymorphism p.D104N impairs the activity of endostatin, resulting in a decreased ability to inhibit angiogenesis. This polymorphism has been previously analyzed in many types of cancer and has been considered a phenotype modulator in some benign and malignant tumors. However, these data are controversial, and different results have been reported for the same tumor types, such as prostate and breast cancer. The purpose of this study was to genotype the p.D104N variant in a cohort of pediatric and adult patients with adrenocortical tumors and to determine its possible association with the biological behavior of adrenocortical tumors. METHODS: DNA samples were obtained from 38 pediatric and 56 adult patients (0.6-75 yrs) with adrenocortical tumors. The DNA samples were obtained from peripheral blood, frozen tissue or paraffin-embedded tumor blocks when blood samples or fresh frozen tissue samples were unavailable. Restriction fragment length polymorphism analysis was used to genotype the patients and 150 controls. The potential associations of the p.D104N polymorphism with clinical and histopathological features and oncologic outcome (age of onset, tumor size, malignant tumor behavior, and clinical syndrome) were analyzed. RESULTS: Both the patient group and the control group were in Hardy-Weinberg equilibrium. The frequencies of the p.D104N polymorphism in the patient group were 81.9% (DD), 15.9% (DN) and 2.2% (NN). In the controls, these frequencies were 80.6%, 17.3% and 2.0%, respectively. We did not observe any association of this variant with clinical or histopathological features or oncologic outcome in our cohort of pediatric and adult patients with adrenocortical tumors.
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Cancer cachexia is a multifaceted syndrome whose aetiology is extremely complex and is directly related to poor patient prognosis and survival. Changes in lipid metabolism in cancer cachexia result in marked reduction of total fat mass, increased lipolysis, total oxidation of fatty acids, hyperlipidaemia, hypertriglyceridaemia, and hypercholesterolaemia. These changes are believed to be induced by inflammatory mediators, such as tumour necrosis factor-alpha (TNF-alpha) and other factors. Attention has recently been drawn to the current theory that cachexia is a chronic inflammatory state, mainly caused by the host's reaction to the tumour. Changes in expression of numerous inflammatory mediators, notably in white adipose tissue (WAT), may trigger several changes in WAT homeostasis. The inhibition of adipocyte differentiation by PPAR gamma is paralleled by the appearance of smaller adipocytes, which may partially account for the inhibitory effect of PPAR gamma on inflammatory gene expression. Furthermore, inflammatory modulation and/or inhibition seems to be dependent on the IKK/NF-kappa B pathway, suggesting that a possible interaction between NF-kappa B and PPAR gamma is required to modulate WAT inflammation induced by cancer cachexia. In this article, current literature on the possible mechanisms of NF-kappa B and PPAR gamma regulation of WAT cells during cancer cachexia are discussed. This review aims to assess the role of a possible interaction between NF-kappa B and PPAR gamma in the setting of cancer cachexia as well as its significant role as a potential modulator of chronic inflammation that could be explored therapeutically. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.
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RAMOS RT, MATTOS DA, REBOUCAS ITS, RANVAUD RD. Space and motion perception and discomfort in air travel. Aviat Space Environ Med 2012; 83:1162-6. Introduction: The perception of comfort during air trips is determined by several factors. External factors like cabin design and environmental parameters (temperature, humidity, air pressure, noise, and vibration) interact with individual characteristics (anxiety traits, fear of flying, and personality) from arrival at the airport to landing at the destination. In this study, we investigated the influence of space and motion discomfort (SMD), fear of heights, and anxiety on comfort perception during all phases of air travel. Methods: We evaluated 51 frequent air travelers through a modified version of the Flight Anxiety Situations Questionnaire (FAS), in which new items were added and where the subjects were asked to report their level of discomfort or anxiety (not fear) for each phase of air travel (Chronbach's alpha = 0.974). Correlations were investigated among these scales: State-Trait Anxiety Inventory (STAB, Cohen's Acrophobia Questionnaire, and the Situational Characteristics Questionnaire (SitQ, designed to estimate SMD levels). Results: Scores of SitQ correlated with discomfort in situations involving space and movement perception (Pearson's rho = 0.311), while discomfort was associated with cognitive mechanisms related to scores in the anxiety scales (Pearson's rho = 0.375). Anxiety traits were important determinants of comfort perception before and after flight, while the influence of SMD was more significant during the time spent in the aircraft cabin. Discussion: SMD seems to be an important modulator of comfort perception in air travel. Its influence on physical well being and probably on cognitive performance, with possible effects on flight safety, deserves further investigation.