Biomimetic biosensor based on lipidic layers containing tyrosinase and lutetium bisphthalocyanine for the detection of antioxidants

This paper describes the preparation of a biomimetic Langmuir-Blodgett film of tyrosinase incorporated in a lipidic layer and the use of lutetium bisphthalocyanine as an electron mediator for the voltammetric detection of phenol derivatives, which include one monophenol (vanillic acid), two diphenols (catechol and caffeic acid) and two triphenols (gallic acid and pyrogallol). The first redox process of the voltammetric responses is associated with the reduction of the enzymatically formed o-quinone and is favoured by the lutetium bisphthalocyanine because significant signal amplification is observed, while the second is associated with the electrochemical oxidation of the antioxidant and occurs at lower potentials in the presence of an electron mediator. The biosensor shows low detection limit (1.98 × 10-6 - 27.49 × 10-6 M), good reproducibility, and high affinity to antioxidants (KM in the range of 62.31-144.87 μM).\ud The excellent functionality of the enzyme obtained using a biomimetic immobilisation method, the selectivity afforded by enzyme catalysis, the signal enhancement caused by the lutetium bisphthalocyanine mediator and the increased selectivity of the curves due to the occurrence of two redox processes make these sensors exceptionally suitable for the detection of phenolic compounds.MICINN (AGL2009-12660/ALI)FAPESPCNPqCAPE

Curcumin Alleviates Matrix Metalloproteinase-3 and -9 Activities during Eradication of Helicobacter pylori Infection in Cultured Cells and Mice

Current therapy-regimens against Helicobacter pylori (Hp) infections have considerable failure rates and adverse side effects that urge the quest for an effective alternative therapy. We have shown that curcumin is capable of eradicating Hp-infection in mice. Here we examine the mechanism by which curcumin protects Hp infection in cultured cells and mice. Since, MMP-3 and -9 are inflammatory molecules associated to the pathogenesis of Hp-infection, we investigated the role of curcumin on inflammatory MMPs as well as proinflammatory molecules. Curcumin dose dependently suppressed MMP-3 and -9 expression in Hp infected human gastric epithelial (AGS) cells. Consistently, Hp-eradication by curcumin-therapy involved significant downregulation of MMP-3 and -9 activities and expression in both cytotoxic associated gene (cag)+ve and cag-ve Hp-infected mouse gastric tissues. Moreover, we demonstrate that the conventional triple therapy (TT) alleviated MMP-3 and -9 activities less efficiently than curcumin and curcumin's action on MMPs was linked to decreased pro-inflammatory molecules and activator protein-1 activation in Hp-infected gastric tissues. Although both curcumin and TT were associated with MMP-3 and -9 downregulation during Hp-eradication, but unlike TT, curcumin enhanced peroxisome proliferator-activated receptor-γ and inhibitor of kappa B-α. These data indicate that curcumin-mediated healing of Hp-infection involves regulation of MMP-3 and -9 activities

The management of acute venous thromboembolism in clinical practice. Results from the European PREFER in VTE Registry

Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in Europe. Data from real-world registries are necessary, as clinical trials do not represent the full spectrum of VTE patients seen in clinical practice. We aimed to document the epidemiology, management and outcomes of VTE using data from a large, observational database. PREFER in VTE was an international, non-interventional disease registry conducted between January 2013 and July 2015 in primary and secondary care across seven European countries. Consecutive patients with acute VTE were documented and followed up over 12 months. PREFER in VTE included 3,455 patients with a mean age of 60.8 ± 17.0 years. Overall, 53.0 % were male. The majority of patients were assessed in the hospital setting as inpatients or outpatients (78.5 %). The diagnosis was deep-vein thrombosis (DVT) in 59.5 % and pulmonary embolism (PE) in 40.5 %. The most common comorbidities were the various types of cardiovascular disease (excluding hypertension; 45.5 %), hypertension (42.3 %) and dyslipidaemia (21.1 %). Following the index VTE, a large proportion of patients received initial therapy with heparin (73.2 %), almost half received a vitamin K antagonist (48.7 %) and nearly a quarter received a DOAC (24.5 %). Almost a quarter of all presentations were for recurrent VTE, with >80 % of previous episodes having occurred more than 12 months prior to baseline. In conclusion, PREFER in VTE has provided contemporary insights into VTE patients and their real-world management, including their baseline characteristics, risk factors, disease history, symptoms and signs, initial therapy and outcomes

RÉCENTS RÉSULTATS EXPÉRIMENTAUX SUR LE RÔLE DES IONS IODURES AINSI QUE SOURCE DE DÉFAUTS RÉTICULAIRES DANS LES MONOCRISTAUX DE BROMURE D'ARGENT

Il est traité de l'action de l'ion iodure dans les monocristaux de bromure d'argent. Il est montré qu'un des principaux rôles des ions I- dans les émulsions photographiques est d'augmenter le nombre de dislocations qui permet de réduire le taux de recombinaison des paires électrons-trous et par voie de conséquence d'augmenter le rendement du processus photographique.This paper intends to give an account of the action of the Iodide ion in single crystals of silver bromide. Lifetime of photoliberated electrons in AgBr, AgBr : I and quenched AgBr crystals were directly measured by means of photoconductivity techniques (at 80 K). Complementary experiments on thermostimulated conductivity and thermoluminescence were also made. The values obtained indicate that electrons are necessarily captured by different traps arising from structural ionized defects created by the I--ions incorporated into the lattice and that the role of these imperfections is to contribute to avoid the electron-hole recombination. It appears to be necessary to reconsider some points of the Mitchell's theory of latent image formation

Thermomechanical characterization of PVDF and P(VDF-TrFE) blends containing corn starch and natural rubber

Films of poly(vinylidene fluoride), PVDF, and poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE), containing corn starch and latex of natural rubber as additives were produced by compressing/annealing forming blends visioning applications as biomaterials. Therefore, considering the possible applications of these blends, a basic characterization has been carried out targeting to infer on their thermomechanical properties. The polymer films (PVDF and P(VDF-TrFE)) with different percentage of additives were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), differential scanning calorimetry (DSC), and dynamical-mechanical analysis (DMA). The compressing/annealing process allowed discarding the necessity of using the solvents to dissolve either PVDF or P(VDF-TrFE), which are usually toxic to human. The results showed that the polymers do not interact chemically with the additives with the blends showing high thermal stability and elasticity modulus at the same order of magnitude of the bone, for instance. The SEM imaged revealed that the blends present morphological structures of typical physical mixtures where each material can be identified within the blends.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Structure and Physical Properties of EVA/Starch Precursor Materials for Foaming Applications

The use of biodegradable materials to develop polymeric blends visioning distinct applications is desirable and nowadays is an important research field. In this work, blends of an ethylene-vinyl acetate copolymer (EVA) and 30, 50, and 70% in weight of an unmodified corn starch have been successfully fabricated. The structure of these blends have been characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). It was found that the original starch particles are kept in the blends forming a separate phase from EVA. The FTIR confirmed that EVA and starch comprise a physical mixture in the blends. Besides, the blends were found very homogenous and mainly amorphous with the EVA melting temperature being independent of the starch content. The melt flow index (MFI) decreased for higher contents of starch, revealing that starch acts as a filler in the blends. Physical properties such as density, hardness, and thermal conductivity were found to increase with the content of starch in the blends. Considering one of the goals of this research, which is producing foams using these blends as precursor materials, the structural and physical characteristics determined here are very satisfactory and open good perspectives in this sense. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 2324-2330, 2011Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES