Ensaio clínico randomizado duplo-cego do perfil inflamatório e do nível de estresse oxidativo em indivíduos com diagnóstico polissonográfico de SAOS antes e após o uso de CPAP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese e caracterização de hidrogéis nanoestruturados contendo nanoargila e zeólita com potencialidade de aplicação em sistemas de liberação controlada de fármacos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Síntese, caracterização e aplicação de hidrogéis nanoestruturados contendo nanoargila para melhorar a germinação e qualidade de muda de hortaliça

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de hidrogéis nanoestruturados baseados em polissacarídeo e zeólita para aplicação em sistemas de liberação controlada

Pós-graduação em Ciência dos Materiais - FEIS

Síntese e caracterização de nanocompósitos constituídos por nanoargila e hidrogel para uso agrícola

Pós-graduação em Ciência dos Materiais - FEIS

Avaliação da atividade antitumoral de uma clinoptilolita de origem natural e outra sintética em modelo experimental de EHRLICH

O câncer destaca-se pela alta incidência e mortalidade. Os tratamentos atualmente usados são agressivos e não específicos, com isso cresce a busca por novas drogas. Uma substância que vem despertando muito interesse são as zeólitas, minerais com característica porosa e estrutura conhecida. Estas possuem ações como adjuvante de vacinas, imunomoduladores e imunoestimuladores, o que desperta o interesse em estuda-las no modelo antitumoral. O presente estudo avaliou o efeito antitumoral e imunomodulador da zeólita natural clinoptilolita e da zeólita comercial, utilizando um modelo de câncer mamário (Tumor de Ehrlich). Para tanto a zeólita natural foi caracterizada (Microscopia Eletrônica de Varredura e Difração de raio X), realizada avaliação da viabilidade celular (ensaio de MTT), determinada a produção de óxido nítrico por macrófagos peritoneais, quantificação de citocinas (ELISA) e avaliação do crescimento tumoral. As zeólitas natural e comercial apresentaram elevada ativação de macrófagos, e não produziram quantidades significativas de NO. A zeólita natural apresentou citotoxicidade frente ao Tumor de Ehrlich em duas concentrações testadas (5 e 25 mg/ml). Não houve liberação significativa da citocina IL-10, no entanto os grupos que foram reestimulados com zeólita natural apresentaram maior liberação de IL-1β e TNF-α. Nos testes in vivo, a zeólita comercial foi a única que apresentou inibição tumoral frente ao Tumor de Ehrlich, sendo necessários estudos mais aprofundados para definir a sua atividade antitumoral nesse tipo celular.

Differences between Tethered Polyelectrolyte Chains on Bare Mica and Hydrophobically Modified Mica

This study investigates the structures of layers of amphiphilic diblock copolymers of poly(t-butyl styrene)-poly- (styrene sulfonate) (PtBS-PSS) adsorbed on both the bare mica surface (hydrophilic) and an octadecyltriethoxysilane (OTE)-modified mica surface (hydrophobic). When the surface is rendered hydrophobic, the nonsoluble block exhibits stronger interaction with the surface and higher adsorbed masses are achieved. Interaction forces between two such adsorbed layers on both substrates were measured using the surface forces apparatus. The effect of salt concentration (Cs) and molecular weight (N) on the height of the self-assembled layers (L0) was examined in each case. The resulting scaling relationship is in good agreement with predictions of the brush model, L0 ∞ N1.0 in the low-salt limit and L0N-1 ∞ (Cs/σ)-0.32 in the salted regime, when adsorption takes place onto the hydrophobized mica surface. For adsorption on the bare mica surface, L0N-0.7 ∞ Cs -0.17 agrees with the scaling prediction of the sparse tethering model. The results suggest that, on the hydrophilic bare mica surface, the adsorbed amount is not high enough to form a brush structure and only very little intermolecular stretching of the tethered chains occurs; in contrast, the presence of the hydrophobic OTE layer increases the tethering density such that the polyelectrolyte chains adopt a brush conformation.

Avaliação da atividade antitumoral de uma clinoptilolita de origem natural e outra sintética em modelo experimental de EHRLICH

O câncer destaca-se pela alta incidência e mortalidade. Os tratamentos atualmente usados são agressivos e não específicos, com isso cresce a busca por novas drogas. Uma substância que vem despertando muito interesse são as zeólitas, minerais com característica porosa e estrutura conhecida. Estas possuem ações como adjuvante de vacinas, imunomoduladores e imunoestimuladores, o que desperta o interesse em estuda-las no modelo antitumoral. O presente estudo avaliou o efeito antitumoral e imunomodulador da zeólita natural clinoptilolita e da zeólita comercial, utilizando um modelo de câncer mamário (Tumor de Ehrlich). Para tanto a zeólita natural foi caracterizada (Microscopia Eletrônica de Varredura e Difração de raio X), realizada avaliação da viabilidade celular (ensaio de MTT), determinada a produção de óxido nítrico por macrófagos peritoneais, quantificação de citocinas (ELISA) e avaliação do crescimento tumoral. As zeólitas natural e comercial apresentaram elevada ativação de macrófagos, e não produziram quantidades significativas de NO. A zeólita natural apresentou citotoxicidade frente ao Tumor de Ehrlich em duas concentrações testadas (5 e 25 mg/ml). Não houve liberação significativa da citocina IL-10, no entanto os grupos que foram reestimulados com zeólita natural apresentaram maior liberação de IL-1β e TNF-α. Nos testes in vivo, a zeólita comercial foi a única que apresentou inibição tumoral frente ao Tumor de Ehrlich, sendo necessários estudos mais aprofundados para definir a sua atividade antitumoral nesse tipo celular.

Impact of bleaching pine fibre on the fibre/cement interface

The goal of this article was to evaluate the surface characteristics of the pine fibres and its impact on the performance of fibre-cement composites. Lower polar contribution of the surface energy indicates that unbleached fibres have less hydrophilic nature than the bleached fibres. Bleaching the pulp makes the fibres less stronger, more fibrillated and permeable to liquids due to removal the amorphous lignin and its extraction from the fibre surface. Atomic force microscopy reveals these changes occurring on the fibre surface and contributes to understanding the mechanism of adhesion of the resulting fibre to cement interface. Scanning electron microscopy shows that pulp bleaching increased fibre/cement interfacial bonding, whilst unbleached fibres were less susceptible to cement precipitation into the fibre cavities (lumens) in the prepared composites. Consequently, bleached fibre-reinforced composites had lower ductility due to the high interfacial adhesion between the fibre and the cement and elevated rates of fibre mineralization.

Systematic Evaluation of Extraction Methods for Multiplatform-Based Metabotyping: Application to the Fasciola hepatica Metabolome

Combining data from multiple analytical platforms is essential for comprehensive study of the molecular phenotype (metabotype) of a given biological sample. The metabolite profiles generated are intrinsically dependent on the analytical platforms, each requiring optimization of instrumental parameters, separation conditions, and sample extraction to deliver maximal biological information. An in-depth evaluation of extraction protocols for characterizing the metabolome of the hepatobiliary fluke Fasciola hepatica, using ultra performance liquid chromatography and capillary electrophoresis coupled with mass spectroscopy is presented. The spectrometric methods were characterized by performance, and metrics of merit were established, including precision, mass accuracy, selectivity, sensitivity, and platform stability. Although a core group of molecules was common to all methods, each platform contributed a unique set, whereby 142 metabolites out of 14,724 features were identified. A mixture design revealed that the chloroform:methanol:water proportion of 15:59:26 was globally the best composition for metabolite extraction across UPLC-MS and CE-MS platforms accommodating different columns and ionization modes. Despite the general assumption of the necessity of platform-adapted protocols for achieving effective metabotype characterization, we show that an appropriately designed single extraction procedure is able to fit the requirements of all technologies. This may constitute a paradigm shift in developing efficient protocols for high-throughput metabolite profiling with more-general analytical applicability.

Liquid Crystal Nanodispersions Enable the Cutaneous Delivery of Photosensitizer for Topical PDT: Fluorescence Microscopy Study of Skin Penetration

Topical photodynamic therapy (PDT) has been applied to almost all types of nonmelanoma skin cancer and numerous superficial benign skin disorders. Strategies to improve the accumulation of photosensitizer in the skin have been studied in recent years. Although the hydrophilic phthalocyanine zinc compound, zinc phthalocyanine tetrasulfonate (ZnPcSO4) has shown high photodynamic efficiency and reduced phototoxic side effects in the treatment of brain tumors and eye conditions, its use in topical skin treatment is currently limited by its poor skin penetration. In this study, nanodispersions of monoolein (MO)-based liquid crystalline phases were studied for their ability to increase ZnPcSO4 uptake by the skin. Lamellar, hexagonal and cubic crystalline phases were prepared and identified by polarizing light microscopy, and the nanodispersions were analyzed by dynamic light scattering. In vitro skin penetration studies were performed using a Franz's cell apparatus, and the skin uptake was evaluated in vivo in hairless mice. Aqueous dispersions of cubic and hexagonal phases showed particles of nanometer size, approximately 224 +/- 10 nm and 188 +/- 10 nm, respectively. In vitro skin retention experiments revealed higher fluorescence from the ZnPcSO4 in deeper skin layers when this photosensitizer was loaded in the hexagonal nanodispersion system when compared to both the cubic phase nanoparticles and the bulk crystalline phases (lamellar, cubic and hexagonal). The hexagonal nanodispersion showed a similar penetration behavior in animal tests. These results are important findings, suggesting the development of MO liquid crystal nanodispersions as potential delivery systems to enhance the efficacy of topical PDT.

Dillapiole as Antileishmanial Agent: Discovery, Cytotoxic Activity and Preliminary SAR Studies of Dillapiole Analogues

In this paper, the isolation of dillapiole (1) from Piper aduncum was reported as well as the semi-synthesis of two phenylpropanoid derivatives [di-hydrodillapiole (2), isodillapiole (3)], via reduction and isomerization reactions. Also, the compounds' molecular properties (structural, electronic, hydrophobic, and steric) were calculated and investigated to establish some preliminary structureactivity relationships (SAR). Compounds were evaluated for in vitro antileishmanial activity and cytotoxic effects on fibroblast cells. Compound 1 presented inhibitory activity against Leishmania amazonensis (IC50?=?69.3 mu M) and Leishmania brasiliensis (IC50?=?59.4 mu M) and induced cytotoxic effects on fibroblast cells mainly in high concentrations. Compounds 2 (IC50?=?99.9 mu M for L. amazonensis and IC50?=?90.5 mu M for L. braziliensis) and 3 (IC50?=?122.9 mu M for L. amazonensis and IC50?=?109.8 mu M for L. brasiliensis) were less active than dillapiole (1). Regarding the molecular properties, the conformational arrangement of the side chain, electronic features, and the hydrophilic/hydrophobic balance seem to be relevant for explaining the antileishmanial activity of dillapiole and its analogues.

Microparticulated Hydrochlorothiazide Solid Dispersion: Enhancing Dissolution Properties via Spray Drying

The aim of the present study was to obtain microparticles of hydrochlorothiazide, a diuretic drug that practically insoluble in water, by spray drying and to investigate the influence of process parameters using a three-level, three-factor Box-Behnken design. Process yields, moisture content, particle size, flowability, and solubility were used to evaluate the spray-dried microparticles. The data were analyzed by response surface methodology using analysis of variance. The independent variables studied were outlet temperature, atomization pressure, and drug content. The formulations were prepared using polyvinylpyrrolidone and colloidal silicon dioxide as the hydrophilic carrier and drying aid, respectively. The microparticle yield ranged from 18.15 to 59.02% and resulted in adequate flow (17 to 32 degrees), moisture content between 2.52 to 6.18%, and mean particle size from 45 to 59 mu m. The analysis of variance showed that the factors studied influenced the yields, moisture content, angle of repose, and solubility. Thermal analysis and X-ray diffractometry evidenced no drug interactions or chemical modifications. Photomicrographs obtained by scanning electron microscopy showed spherical particles. The solubility and dissolution rates of hydrochlorothiazide were remarkably improved when compared with pure drug. Therefore, the results confirmed the high potential of the spray-drying technique to obtain microparticulate hydrochlorothiazide with enhanced pharmaceutical and dissolution properties.

Enzyme Microheterogeneous Hydration and Stabilization in Supercritical Carbon Dioxide

Supercritical carbon dioxide is a promising green-chemistry solvent for many enzyme-catalyzed chemical reactions, yet the striking stability of some enzymes in such unconventional environments is not well understood. Here, we investigate the stabilization of the Candida antarctica Lipase B (CALB) in supercritical carbon dioxide-water biphasic systems using molecular dynamics simulations. The preservation of the enzyme structure and optimal activity depend on the presence of small amounts of water in the supercritical dispersing medium. When the protein is at least partially hydrated, water molecules bind to specific sites on the enzyme surface and prevent carbon dioxide from penetrating its catalytic core. Strikingly, water and supercritical carbon dioxide cover the protein surface quite heterogeneously. In the first solvation layer, the hydrophilic residues at the surface of the protein are able to pin down patches of water, whereas carbon dioxide solvates preferentially hydrophobic surface residues. In the outer solvation shells, water molecules tend to cluster predominantly on top of the larger water patches of the first solvation layer instead of spreading evenly around the remainder of the protein surface. For CALB, this exposes the substrate-binding region of the enzyme to carbon dioxide, possibly facilitating diffusion of nonpolar substrates into the catalytic funnel. Therefore, by means of microheterogeneous solvation, enhanced accessibility of hydrophobic substrates to the active site can be achieved, while preserving the functional structure of the enzyme. Our results provide a molecular picture on the nature of the stability of proteins in nonaqueous media.

Application of Polysaccharide Hydrogels in Adsorption and Controlled-Extended Release of Fertilizers Processes

This article studied the applicability of poly(acrylamide) and methylcellulose (PAAm-MC) hydrogels as potential delivery vehicle for the controlled-extended release of ammonium sulfate (NH(4))(2)SO(4) and potassium phosphate (KH(2)PO(4)) fertilizers. PAAm-MC hydrogels with different acrylamide (AAm) and MC concentrations were prepared by a free radical polymerization method. The adsorption and desorption kinetics of fertilizers were determined using conductivity measurements based on previously built analytical curve. The addition of MC in the PAAm chains increased the quantities of (NH(4))(2)SO(4) and KH(2)PO(4) loaded and extended the time and quantities of fertilizers released. Coherently, both loading and releasing processes were strongly influenced by hydrophilic properties of hydrogels (AAm/MC mass proportion). The best sorption (124.0 mg KH(2)PO(4)/g hydrogel and 58.0 mg (NH(4))(2)SO(4)/g hydrogel) and desorption (54.9 mg KH(2)PO(4)/g hydrogel and 49.5 mg (NH(4))(2)SO(4)/g hydrogel) properties were observed for 6.0% AAm-1.0% MC hydrogels (AAm/MC mass proportion equal 6), indicating that these hydrogels are potentially viable to be used in controlled-extended release of fertilizers systems. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 2291-2298, 2012