1000 resultados para Ricardo Ferraço


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Electrospray ionization mass spectrometric analysis of lapachol (2-hydroxy-3-(3-methy1-2-butenyl)-1,4-naphthoquinone) was accomplished in order to elucidate the gas-phase dissociation reactions of this important biologically active natural product. The occurrence of protonated and cationized species in the positive mode and of deprotonated species in the negative mode was explored by means of collision-induced dissociation (CID) experiments. For the protonated molecule, the H(2)O and C(4)H(8) losses occur by two competitive channels. For the deprotonated molecule, the even-electron rule is not conserved, and the radicalar species are eliminated by formation of distonic anions. The fragmentation mechanism for each ion was suggested on the basis of computational thermochemistry. Atomic charges, relative energies, and frontier orbitals were employed aiming at a better understanding of the gas-phase reactivity of lapachol. Potential energy surfaces for fragmentation reactions were obtained by the B3LYP/6-31+G(d,p) model. Copyright (C) 2010 John Wiley & Sons, Ltd.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The phytochemical investigation of Dimerostemma arnottii (Asteraceae) afforded, in addition to a known eudesmanolide, two unusual eudesmane methyl ester derivatives and a new eudesmanolide. Structural elucidation of the compounds was based on their ID and 2D NMR spectroscopic as well as HR-ESI-MS data. There is a remarkable similarity between the structures of the eudesmanes from D. arnottii and those previously encountered in other Dimerostemma species, which is in agreement with the results of a previous phylogenetic study based on molecular data. The chemotaxonomic relevance of the isolated compounds is briefly discussed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Blood pressure (BP) within pre-hypertensive levels confers higher cardiovascular risk and is an intermediate stage for full hypertension, which develops in an annual rate of 7 out of 100 individuals with 40 to 50 years of age. Non-drug interventions to prevent hypertension have had low effectiveness. In individuals with previous cardiovascular disease or diabetes, the use of BP-lowering agents reduces the incidence of major cardiovascular events. In the absence of higher baseline risk, the use of BP agents reduces the incidence of hypertension. The PREVER-prevention trial aims to investigate the efficacy, safety and feasibility of a population-based intervention to prevent the incidence of hypertension and the development of target-organ damage. Methods: This is a randomized, double-blind, placebo-controlled clinical trial, with participants aged 30 to 70 years, with pre-hypertension. The trial arms will be chlorthalidone 12.5 mg plus amiloride 2.5 mg or identical placebo. The primary outcomes will be the incidence of hypertension, adverse events and development or worsening of microalbuminuria and of left ventricular hypertrophy in the EKG. The secondary outcomes will be fatal or non-fatal cardiovascular events: myocardial infarction, stroke, heart failure, evidence of new sub-clinical atherosclerosis, and sudden death. The study will last 18 months. The sample size was calculated on the basis of an incidence of hypertension of 14% in the control group, a size effect of 40%, power of 85% and P alpha of 5%, resulting in 625 participants per group. The project was approved by the Ethics committee of each participating institution. Discussion: The early use of blood pressure-lowering drugs, particularly diuretics, which act on the main mechanism of blood pressure rising with age, may prevent cardiovascular events and the incidence of hypertension in individuals with hypertension. If this intervention shows to be effective and safe in a population-based perspective, it could be the basis for an innovative public health program to prevent hypertension in Brazil.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The aim of present study was to verify the in vitro antitumor activity of a ruthenium complex, cis-(dichloro)tetraammineruthenium(III) chloride (cis-[RuCl(2)(NH(3))(4)]Cl) toward different tumor cell lines. The antitumor studies showed that ruthenium(III) complex presents a relevant cytotoxic activity against murine B cell lymphoma (A-20), murine ascitic sarcoma 180 (S-180), human breast adenocarcinoma (SK-BR-3), and human T cell leukemia (Jurkat) cell lines and a very low cytotoxicity toward human peripheral blood mononuclear cells. The ruthenium(III) complex decreased the fraction of tumor cells in G0/G1 and/or G2-M phases, indicating that this compound may act on resting/early entering G0/G1 cells and/or precycling G2-M cells. The cytotoxic activity of a high concentration (2 mg mL(-1)) of cis-[RuCl(2)(NH(3))(4)]Cl toward Jurkat cells correlated with an increased number of annexin V-positive cells and also the presence of DNA fragmentation, suggesting that this compound induces apoptosis in tumor cells. The development of new antineoplastic medications demands adequate knowledge in order to avoid inefficient or toxic treatments. Thus, a mechanistic understanding of how metal complexes achieve their activities is crucial to their clinical success and to the rational design of new compounds with improved potency.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Ruthenium compounds in general are well suited for medicinal applications. They have been investigated as immunosuppressants, nitric oxide scavengers, antimicrobial agents, and antimalarials. The aim of this study is to evaluate the immunomodulatory activity of cis-(dichloro) tetraammineruthenium(III) chloride (cis-[RuCl(2)(NH(3))(4)]Cl) on human peripheral blood mononuclear cells (PBMC). The cytotoxic studies performed here revealed that the ruthenium( III) complex presents a cytotoxic activity towards normal human PBMC, only at very high concentration. Results also showed that cis-[ RuCl(2)(NH(3))(4)] Cl presents a dual role on PBMC stimulating proliferation and interleukin-2 (IL-2) production at low concentration and inducing cytotoxicity, inability to proliferate, and inhibiting IL-2 production at high concentration. The noncytotoxic activity of cis-[RuCl(2)(NH(3))(4)] Cl at low concentration towards PBMC, which correlates with the small number of annexin V positive cells and also the absence of DNA fragmentation, suggest that this compound does not induce apoptosis on PBMC. For the first time, we show that, at low concentration (10-100 mu g L(-1)), the cis-[ RuCl(2)(NH(3))(4)] Cl compound induces peripheral blood lymphocytes proliferation and also stimulates them to IL-2 production. These results open a new potential applicability of ruthenium(III) complexes as a possible immune regulatory compound acting as immune suppressor at high concentration and as immune stimulator at low concentration.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The use of metformin throughout gestation by pregnant women with polycystic ovary syndrome (PCOS) significantly reduces the number of first trimester spontaneous abortions and the rate of occurrence of gestational diabetes. The objective of this study was to investigate the pharmacokinetics and the placental transfer of metformin in pregnant women with PCOS. Eight pregnant women with PCOS taking 850 mg metformin every 12 h during the third trimester of pregnancy were evaluated. Maternal blood samples were collected at steady state during the dose interval (0-12 h). Maternal and umbilical cord blood samples were also obtained at delivery. Metformin plasma concentrations were analyzed by high-performance liquid chromatography, and pharmacokinetic parameters were determined using a non-compartmental model. Data are reported as median and minimum and maximum values. Metformin pharmacokinetic parameters were: t(A1/2), 3.8 (2.8-5.4) h; t(max), 2.0 (0.5-3.0) h; C(max), 1.4 (0.5-2.1) mg/L; C(mean), 0.5 (0.2-0.9) mg/L; AUC(0-12), 6.4 (1.1-9.2) mg h/L; Cl/f, 105 (60-274) L/h; Vd/f, 551 (385-1173) L; median fluctuation, 89 (79-95)%. Umbilical/maternal metformin plasma concentration ratios were 0.7 (0.4-1.3). Metformin oral clearance (Cl/f) had increased in our patients relative to nonpregnant healthy volunteers or diabetic patients. Therefore, lower plasma metformin concentrations were observed for nondiabetic pregnant women with PCOS. Future studies should be conducted to demonstrate the therapeutic efficacy of metformin during pregnancy. Caution is warranted as umbilical/maternal metformin plasma concentrations ratios of around 0.7 require metformin dosage adjustment.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Purpose This study investigated the influence of gestational diabetes mellitus on the kinetic disposition and stereoselective metabolism of labetalol administered intravenously or orally. Methods Thirty hypertensive women during the last trimester of pregnancy were divided into four groups: non-diabetic and diabetic women treated with intravenous or oral labetalol. Results The pharmacokinetics of labetalol was not stereoselective in diabetic or non-diabetic pregnant women receiving the drug intravenously. However, oral administration of labetalol resulted in lower values of the area under the plasma concentration versus time curve (AUC) for the beta-blocker (RR) than for the other enantiomers in both diabetic and non-diabetic women. Gestational diabetes mellitus caused changes in the kinetic disposition of the labetalol stereoisomers when administered orally. The AUC values for the less potent adrenoceptor antagonist (SS) and for the alpha-blocking (SR) isomers were higher in diabetic than in non-diabetic pregnant women. Conclusions The approximately 100% higher AUC values obtained for the (SR) isomer in diabetic pregnant women treated with oral labetalol may be of clinical relevance in terms of the alpha-blocking activity of this isomer.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The present study reports on the preparation and testing of a desoxycholate amphotericin B (D-AMB) sustained delivery system based on poly(lactic-co-glycolic acid) (PLGA) and dimercaptosuccinic acid (DMSA) polymeric blends (Nano-D-AMB) aimed at reducing the number of AMB administrations required to treat mycosis. BALB/c mice were infected with the yeast Paracoccidioides brasiliensis intravenously to mimic the chronic form of paracoccidioidomycosis. At 30 days post-infection, the animals were treated with Nano-D-AMB [6 mg/kg of encapsulated D-AMB, intraperitoneally (ip), interval of 72 h] or D-AMB (2 mg/kg, ip, interval of 24 h). Drug efficacy was investigated by the fungal burden recovery from tissues. Toxicity was assessed by renal and hepatic biochemical parameters, physical appearance of the animals and haematological investigation. The control groups used were non-infected and the infected mice mock treated with PBS. Nano-D-AMB presented results comparable to free D-AMB, with a marked antifungal efficacy. The Nano-D-AMB-treated group presented lower loss of body weight and absence of stress sign (piloerection and hypotrichosis) observed after D-AMB treatment. No renal [blood urea nitrogen (BUN), creatinine] or hepatic (pyruvic and oxalacetic glutamic transaminases) biochemical abnormalities were found. The micronucleus assay showed no significant differences in both the micronucleus frequency and percentage of polychromatic erythrocytes for Nano-D-AMB, indicating the absence of genotoxicity and cytotoxic effects. The D-AMB-coated PLGA-DMSA nanoparticle showed antifungal efficacy, fewer undesirable effects and a favourable extended dosing interval. Nano-D-AMB comprises an AMB formulation able to lessen the number of drug administrations. Further studies would elucidate whether Nano-D-AMB would be useful to treat systemic fungal infections such as paracoccidioidomycosis, candidiasis, aspergillosis and cryptococcosis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Mutations of Kit at position D816 have been implicated in mastocytosis, acute myeloid leukaemia and germ cell tumours. Expression of this mutant Kit in cell lines results in factor-independent growth, differentiation and increased survival in vitro and tumourigenicity in vivo. Mutant D816VKit and wild-type Kit were expressed in murine primary haemopoietic cells and grown in stem cell factor (SCF) or the absence of factors. Expression of D816VKit did not lead to transformation as assessed by a colony assay, but resulted in enhanced differentiation of cells when compared to control cells. D816VKit induced an increase in the number of cells differentiating along the megakaryocyte lineage in the absence of factors. SCF had an added effect with an increase in differentiation of mast cells. Expression of wild-type Kit in the presence of SCF also failed to cause transformation and induced differentiation of mast cells and megakaryocytes. We conclude that constitutive expression of D816VKit in primary haemopoietic cells is not a sufficient transforming stimulus but leads to the survival and maturation of cells whose phenotype is influenced by the presence of SCF. (C) 2003 Elsevier Science Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The increase of the women purchase power has led some companies to adopt strategies of products differentiation as well as to produce specific products to the female public. The auto industry is not immune to this phenomenon, once the women represent, approximately half of the automobile sales in the country. Considering the consumption and the behavior differences between women and men, it has set the following question: are there differences between the choices associated to the automobile by men and the choices associated to the automobile by women? It has been presented to the participants items found in the people`s day-by-day, which are valorized by them, and the participants have been asked to choose and associate these items to the automobile. The results analysis revealed there are more similarities than differences between choices associated to the automobile by men ad choices associated to the automobile by women. The similarity between the choices suggests that the representations, the meanings and values assigned. to the car by men ana women are similar and thus the strategy of product differentiation does not apply to the automotive industry

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This special section brings together 4 of the 12 studies conducted within a research program analyzing the relationships among social mobilization, governance. and rural development in contemporary Latin America. The introduction Lives an overview of the contemporary significance of social movements For rural development dynamics in the region, and of the principal insights of the section papers and the broader research program of which they were a part. This significance varies Lis an effect of two distinct and uneven geographics: the geography of social movements themselves and the geography of the rural political economy. The effects that movements have oil the political economy of rural development also depend significantly oil internal characteristics of these movements. The paper identifies several such characteristics. The general pattern is that movements have had far more effect oil widening the political inclusiveness of rural development than they have oil improving its economic inclusiveness and dynamism. (c) 2008 Elsevier Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The incentives and governance system of organizations are important in explaining how they behave in localized development processes. This article builds on the observation that the literature on territorial development does not generally address the action of social movements. At the same time, research on social movements rarely studies their effects on the territories ill which they act. This text is a contribution to fill this gap. It compares two social movement organizations: a trade union federation and a credit cooperative system operating throughout southern Brazil, Both organizations share common origins and social bases, yet their impacts oil territories have been quite different. The analysis focuses Oil the social ties that link trade unions and cooperatives to their territories to show that governance systems may explain the performance of each organization, especially with regard to their capacity for innovation. (c) 2008 Elsevier Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

To attend and obtain the systems and. internal controls mechanisms proposed by Sarbanes-Oxley certifications is actually a big challenge,for most of the multinational companies registered in SEC (US Securities and Exchange Commission). This work has the objective of contributing to the analysis of this methodology, not only to attend the law but to reduce cost and generate value through the strengthen of the internal control systems, turning them into animating value generation process mechanisms. So, the idea is to identify the main gaps in the theory through the literature revision and a case study in order to put a question to the main deficiencies, strong points or contributions through the evaluation of the noticed practices. Finally, we can say that a a result of the research and the analyses made in. this case, the vast majority of executives and other employees recognize the benefit that Sarbanes-Oxley Act has brought to the company searched. Also recognize that, although there is still necessity for systemic adequacy and infrastructure, it helps and reinforce reducing and controlling the risks. the system of internal controls in all areas of expertise. They approach and understand that there is the need for a change in the other employees` culture to be inserted in the day-today routine as internal controls, attention to Sarbanes-Oxley and Corporate Governance, making the control cost smaller when compared to the benefits generated.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cyrtopodium includes similar to 42 species, among which is Cyrtopodium polyphyllum (Vell.) Pabst ex F. Barros that occurs in a rainforest in south-eastern Brazil. Its non-rewarding flowers, which attract Centridini bees by deceit, are rain-assisted self-pollinated, a phenomenon rarely found in orchids and other plant families. In addition, self-pollination has never been reported in Cyrtopodiinae and data on the pollination of South American orchids are scarce. Flowers were observed at different times of the day, on both sunny and rainy days, to record floral morphology, visitors and the effects of rainfall on flowers. On rainy days, water accumulates on the stigma and dissolves the adhesive substance of the stigmatic surface. A viscous drop thus forms, which contacts the pollinarium. When evaporation makes the viscous drop shrink, the drop moves the pollinarium with the anther onto the stigmatic surface and promotes self-pollination. Fruit set in natural habitat was low, with 2.4% at one study site, where a similar value (2.2%) was recorded in flowers self-pollinated by rain. In C. polyphyllum, facultative self-pollination assisted by rain is thus an important strategy that guarantees fruit set when pollinator`s visits are scarce, which is common in species pollinated by deceit.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

(Triphora uniflora A.C. Ferreira, Baptista & Pansarin (Orchidaccae: Triphorcae): a new species and the first record of the genus Triphora Nutt. for Sao Paulo state, Brazil). Triphora uniflora A. C. Ferreira, Baptista & Pansarin, a new species of Orchidaceae, is described and illustrated. Furthermore, this is the first report of the genus Triphora for Sao Paulo state, Brazil. The relationship of this new species to other taxa of the genus and the need to preserve the natural habitat of this Triphora species are discussed.