Bleeding Complications In Dengue Are Not Associated With Significant Changes In The Modulators Of The Endothelial Barrier.

Bleeding complications in dengue may occur irrespective of the presence of plasma leakage. We compared plasma levels of modulators of the endothelial barrier among three dengue groups: bleedings without plasma leakage, dengue hemorrhagic fever, and non-complicated dengue. The aim was to evaluate whether the presence of subtle alterations in microvascular permeability could be detected in bleeding patients. Plasma levels of VEGF-A and its soluble receptors were not associated with the occurrence of bleeding in patients without plasma leakage. These results provide additional rationale for considering bleeding as a complication independent of endothelial barrier breakdown, as proposed by the 2009 WHO classification.

Evidences Of Endocytosis Via Caveolae Following Blood-brain Barrier Breakdown By Phoneutria Nigriventer Spider Venom.

Spider venoms contain neurotoxic peptides aimed at paralyzing prey or for defense against predators; that is why they represent valuable tools for studies in neuroscience field. The present study aimed at identifying the process of internalization that occurs during the increased trafficking of vesicles caused by Phoneutria nigriventer spider venom (PNV)-induced blood-brain barrier (BBB) breakdown. Herein, we found that caveolin-1α is up-regulated in the cerebellar capillaries and Purkinje neurons of PNV-administered P14 (neonate) and 8- to 10-week-old (adult) rats. The white matter and granular layers were regions where caveolin-1α showed major upregulation. The variable age played a role in this effect. Caveolin-1 is the central protein that controls caveolae formation. Caveolar-specialized cholesterol- and sphingolipid-rich membrane sub-domains are involved in endocytosis, transcytosis, mechano-sensing, synapse formation and stabilization, signal transduction, intercellular communication, apoptosis, and various signaling events, including those related to calcium handling. PNV is extremely rich in neurotoxic peptides that affect glutamate handling and interferes with ion channels physiology. We suggest that the PNV-induced BBB opening is associated with a high expression of caveolae frame-forming caveolin-1α, and therefore in the process of internalization and enhanced transcytosis. Caveolin-1α up-regulation in Purkinje neurons could be related to a way of neurons to preserve, restore, and enhance function following PNV-induced excitotoxicity. The findings disclose interesting perspectives for further molecular studies of the interaction between PNV and caveolar specialized membrane domains. It proves PNV to be excellent tool for studies of transcytosis, the most common form of BBB-enhanced permeability.

Chemical Immobilization Of Crosslinked Polymeric Ionic Liquids On Nitinol Wires Produces Highly Robust Sorbent Coatings For Solid-phase Microextraction.

Super elastic nitinol (NiTi) wires were exploited as highly robust supports for three distinct crosslinked polymeric ionic liquid (PIL)-based coatings in solid-phase microextraction (SPME). The oxidation of NiTi wires in a boiling (30%w/w) H2O2 solution and subsequent derivatization in vinyltrimethoxysilane (VTMS) allowed for vinyl moieties to be appended to the surface of the support. UV-initiated on-fiber copolymerization of the vinyl-substituted NiTi support with monocationic ionic liquid (IL) monomers and dicationic IL crosslinkers produced a crosslinked PIL-based network that was covalently attached to the NiTi wire. This alteration alleviated receding of the coating from the support, which was observed for an analogous crosslinked PIL applied on unmodified NiTi wires. A series of demanding extraction conditions, including extreme pH, pre-exposure to pure organic solvents, and high temperatures, were applied to investigate the versatility and robustness of the fibers. Acceptable precision of the model analytes was obtained for all fibers under these conditions. Method validation by examining the relative recovery of a homologous group of phthalate esters (PAEs) was performed in drip-brewed coffee (maintained at 60 °C) by direct immersion SPME. Acceptable recoveries were obtained for most PAEs in the part-per-billion level, even in this exceedingly harsh and complex matrix.

Vascular Endothelial Growth Factor Increases During Blood-brain Barrier-enhanced Permeability Caused By Phoneutria Nigriventer Spider Venom.

Phoneutria nigriventer spider accidental envenomation provokes neurotoxic manifestations, which when critical, results in epileptic-like episodes. In rats, P. nigriventer venom (PNV) causes blood-brain barrier breakdown (BBBb). The PNV-induced excitotoxicity results from disturbances on Na(+), K(+) and Ca(2+) channels and glutamate handling. The vascular endothelial growth factor (VEGF), beyond its angiogenic effect, also, interferes on synaptic physiology by affecting the same ion channels and protects neurons from excitotoxicity. However, it is unknown whether VEGF expression is altered following PNV envenomation. We found that adult and neonates rats injected with PNV showed immediate neurotoxic manifestations which paralleled with endothelial occludin, β-catenin, and laminin downregulation indicative of BBBb. In neonate rats, VEGF, VEGF mRNA, and Flt-1 receptors, glutamate decarboxylase, and calbindin-D28k increased in Purkinje neurons, while, in adult rats, the BBBb paralleled with VEGF mRNA, Flk-1, and calbindin-D28k increases and Flt-1 decreases. Statistically, the variable age had a role in such differences, which might be due to age-related unequal maturation of blood-brain barrier (BBB) and thus differential cross-signaling among components of the glial neurovascular unit. The concurrent increases in the VEGF/Flt-1/Flk-1 system in the cerebellar neuron cells and the BBBb following PNV exposure might imply a cytokine modulation of neuronal excitability consequent to homeostatic perturbations induced by ion channels-acting PNV neuropeptides. Whether such modulation represents neuroprotection needs further investigation.

Role Of Astrocytes In Thiamine Deficiency.

Thiamine deficiency (TD) is the underlying cause of Wernicke's encephalopathy (WE), an acute neurological disorder characterized by structural damage to key periventricular structures in the brain. Increasing evidence suggests these focal histological lesions may be representative of a gliopathy in which astrocyte-related changes are a major feature of the disorder. These changes include a loss of the glutamate transporters GLT-1 and GLAST concomitant with elevated interstitial glutamate levels, lowered brain pH associated with increased lactate production, decreased levels of GFAP, reduction in the levels of glutamine synthetase, swelling, alterations in levels of aquaporin-4, and disruption of the blood-brain barrier. This review focusses on how these manifestations contribute to the pathophysiology of TD and possibly WE.

Endocytosis Of Tight Junctions Caveolin Nitrosylation Dependent Is Improved By Cocoa Via Opioid Receptor On Rpe Cells In Diabetic Conditions.

Retinal pigment epithelium cells, along with tight junction (TJ) proteins, constitute the outer blood retinal barrier (BRB). Contradictory findings suggest a role for the outer BRB in the pathogenesis of diabetic retinopathy (DR). The aim of this study was to investigate whether the mechanisms involved in these alterations are sensitive to nitrosative stress, and if cocoa or epicatechin (EC) protects from this damage under diabetic (DM) milieu conditions. Cells of a human RPE line (ARPE-19) were exposed to high-glucose (HG) conditions for 24 hours in the presence or absence of cocoa powder containing 0.5% or 60.5% polyphenol (low-polyphenol cocoa [LPC] and high-polyphenol cocoa [HPC], respectively). Exposure to HG decreased claudin-1 and occludin TJ expressions and increased extracellular matrix accumulation (ECM), whereas levels of TNF-α and inducible nitric oxide synthase (iNOS) were upregulated, accompanied by increased nitric oxide levels. This nitrosative stress resulted in S-nitrosylation of caveolin-1 (CAV-1), which in turn increased CAV-1 traffic and its interactions with claudin-1 and occludin. This cascade was inhibited by treatment with HPC or EC through δ-opioid receptor (DOR) binding and stimulation, thereby decreasing TNF-α-induced iNOS upregulation and CAV-1 endocytosis. The TJ functions were restored, leading to prevention of paracellular permeability, restoration of resistance of the ARPE-19 monolayer, and decreased ECM accumulation. The detrimental effects on TJs in ARPE-19 cells exposed to DM milieu occur through a CAV-1 S-nitrosylation-dependent endocytosis mechanism. High-polyphenol cocoa or EC exerts protective effects through DOR stimulation.

Molecular Variations In Aromatic Cosolutes: Critical Role In The Rheology Of Cationic Wormlike Micelles.

Wormlike micelles formed by the addition to cetyltrimethylammonium bromide (CTAB) of a range of aromatic cosolutes with small molecular variations in their structure were systematically studied. Phenol and derivatives of benzoate and cinnamate were used, and the resulting mixtures were studied by oscillatory, steady-shear rheology, and the microstructure was probed by small-angle neutron scattering. The lengthening of the micelles and their entanglement result in remarkable viscoelastic properties, making rheology a useful tool to assess the effect of structural variations of the cosolutes on wormlike micelle formation. For a fixed concentration of CTAB and cosolute (200 mmol L(-1)), the relaxation time decreases in the following order: phenol > cinnamate> o-hydroxycinnamate > salicylate > o-methoxycinnamate > benzoate > o-methoxybenzoate. The variations in viscoelastic response are rationalized by using Mulliken population analysis to map out the electronic density of the cosolutes and quantify the barrier to rotation of specific groups on the aromatics. We find that the ability of the group attached to the aromatic ring to rotate is crucial in determining the packing of the cosolute at the micellar interface and thus critically impacts the micellar growth and, in turn, the rheological response. These results enable us for the first time to propose design rules for the self-assembly of the surfactants and cosolutes resulting in the formation of wormlike micelles with the cationic surfactant CTAB.

Application Of A Semi-empirical Model For The Evaluation Of Transmission Properties Of Barite Mortar.

The aim of this study was to estimate barite mortar attenuation curves using X-ray spectra weighted by a workload distribution. A semi-empirical model was used for the evaluation of transmission properties of this material. Since ambient dose equivalent, H(⁎)(10), is the radiation quantity adopted by IAEA for dose assessment, the variation of the H(⁎)(10) as a function of barite mortar thickness was calculated using primary experimental spectra. A CdTe detector was used for the measurement of these spectra. The resulting spectra were adopted for estimating the optimized thickness of protective barrier needed for shielding an area in an X-ray imaging facility.

Factors Controlling The Deposition Of Silk Fibroin Nanofibrils During Layer-by-layer Assembly.

The layer-by-layer technique has been used as a powerful method to produce multilayer thin films with tunable properties. When natural polymers are employed, complicated phenomena such as self-aggregation and fibrilogenesis can occur, making it more difficult to obtain and characterize high-quality films. The weak acid and base character of such materials provides multilayer systems that may differ from those found with synthetic polymers due to strong self-organization effects. Specifically, LbL films prepared with chitosan and silk fibroin (SF) often involve the deposition of fibroin fibrils, which can influence the assembly process, surface properties, and overall film functionality. In this case, one has the intriguing possibility of realizing multilayer thin films with aligned nanofibers. In this article, we propose a strategy to control fibroin fibril formation by adjusting the assembly partner. Aligned fibroin fibrils were formed when chitosan was used as the counterpart, whereas no fibrils were observed when poly(allylamine hydrochloride) (PAH) was used. Charge density, which is higher in PAH, apparently stabilizes SF aggregates on the nanometer scale, thereby preventing their organization into fibrils. The drying step between the deposition of each layer was also crucial for film formation, as it stabilizes the SF molecules. Preliminary cell studies with optimized multilayers indicated that cell viability of NIH-3T3 fibroblasts remained between 90 and 100% after surface seeding, showing the potential application of the films in the biomedical field, as coatings and functional surfaces.

Estudo teórico da interação existente entre a artemisinina e o heme

The purpose of this work is to study theoretically stereoelectronic aspects of the interaction between heme and artemisinin in the transitional heme-artemisinin complex. Through semi-empirical calculations using the PM3 method, the potential energy barrier of artemisinin rotation relative to heme in the heme-artemisinin complex was studied in vacuum and in the partially solvated state. The minimum heat of formation obtained for the complex with and without water molecules is -702.39 and -100.86 kcal mol-1, respectively, which corresponds to the dihedral angle C-Fe-O1-O2 of 43.93º and 51.90º around the iron-oxygen O1 bond, respectively. The water molecules bind to heme via 13 hydrogen bonds and O-H O and 6 C-H O interactions, which accounts for -67.23 kcal mol-1. It is observed that the inclusion of water molecules does not affect significantly the stability of the heme-artemisinin complex.

Qualidade pós-colheita de caqui 'fuyu' com utilização de diferentes concentrações de cobertura comestível

One of the main objectives of applying edible coatings on fruits surface is to create a protective film to reduce weight loss due to evaporation and transpiration and also to decrease the risk of fruit rot caused by environmental contamination, in order to improve the visual aspect. Therefore, it is possible to increase shelf life, and decrease post harvest losses. Persimmon is a much appreciated fruit, with high potential for export, but sensitive to handling and storage. This study aimed to evaluate the effect of applying the edible coating Megh Wax ECF-124 (18% of active composts, consisting of emulsion of carnauba wax, anionic surfactant, preservative and water) produced by Megh Industry and Commerce Ltda in three different concentrations (25, 50 and 100%) on post harvest quality of 'Fuyu' persimmon stored for 14 days. The attributes evaluated for quality were: firmness, pH, acidity, soluble solids, weight loss and color. The results showed that application of carnauba wax in different concentrations was effective on decreasing weight loss of persimmon cv. Fuyu and maintenance of color aspects. Treatment at lower concentration, 25%, showed lower rate of discharge, but high concentrations showed lower values of mass loss. Carnauba wax application showed a high potential for use on postharvest conservation, and can be applied together with other technologies, helping to maintain quality for export.

Caracterização sensorial de amêndoas de castanha-de-caju fritas e salgadas

Shelled, roasted and salted cashew nut kernels were packaged in three different flexible materials (PP/PE= polypropylene / polyethylene; PETmet/PE= metallized polyethylene terephthalate / polyethylene; PET/Al/LDPE= polyethylene terephthalate / aluminum foil / low density polyethylene ), with different barrier properties. Kernels were stored for one year at 30° C and 80% relative humidity. Quantitative descriptive sensory analysis (QDA) were performed at the end of storage time. Descriptive terms obtained for kernels characterization were brown color, color uniformity and rugosity for appearance; toasted kernel, sweet, old and rancidity for odor; toasted kernel, sweet, old rancidity, salt and bitter for taste, crispness for texture. QDA showed that factors responsible for sensory quality decrease, after one year storage, were increase in old aroma and taste, increase in rancidity aroma and taste, decrease in roasted kernel aroma and taste, and decrease of crispness. Sensory quality decrease was higher in kernels packaged in PP/PE.

Desidratação osmótica de abacaxi aplicada à tecnologia de métodos combinados

The aim of this research was to optimize osmotic dehydration of pineapple, according to two criteria: maximize water loss and minimize solid gain. The process was made as an application to Combined Methods Technology, in which three preservation factors were combined: water activity, pH and chemical preservatives, all being applied at low levels, in order to get a product resembling non-processed fruit. The experiment was divided into three treatments, being: non-coated pineapple pieces (A), pieces coated with alginate (B) and coated with low-methoxyl pectin (C). Process involved the following main steps: enzymatic inactivation of fruit pieces; in treatments B and C, incorporation of their respective coatings; and osmotic dehydration, in sucrose syrup containing potassium sorbate and citric acid. Optimum conditions, determined from Response Surface Methodology, were the following: dehydration of fruit pieces coated by alginate, at 42-47° C, in sucrose syrup at 66-69° Brix, for 220 to 270 minutes. Results indicated that both coatings significantly affected the mass transfers of the process, reducing solid incorporation and increasing water loss; therefore, increasing weight loss and performance ratio (water loss: solid incorporation) took place. Water activity was not significantly affected by the coatings. The product obtained under optimum conditions was submitted to sensorial evaluation, and presented a good general acceptance. Moulds and yeasts countings indicated good microbiological stability of the product for at least 60 days at 30ºC.

Barreiras socio-culturais e lazer das pessoas portadoras de deficiencia fisica : um estudo do grupo Fraternidade Cristã de Doença e Deficiencia de Campinas, SP

Universidade Estadual de Campinas. Faculdade de Educação Física