1,872 research outputs found
Nitric Oxide Regulates Neurogenesis in the Hippocampus following Seizures
Hippocampal neurogenesis is changed by brain injury. When neuroinflammation accompanies injury, activation of resident microglial cells promotes the release of inflammatory cytokines and reactive oxygen/nitrogen species like nitric oxide (NO). In these conditions, NO promotes proliferation of neural stem cells (NSC) in the hippocampus. However, little is known about the role of NO in the survival and differentiation of newborn cells in the injured dentate gyrus. Here we investigated the role of NO following seizures in the regulation of proliferation, migration, differentiation, and survival of NSC in the hippocampus using the kainic acid (KA) induced seizuremouse model. We show that NO increased the proliferation of NSC and the number of neuroblasts following seizures but was detrimental to the survival of newborn neurons. NO was also required for the maintenance of long-term neuroinflammation. Taken together, our data show that NO positively contributes to the initial stages of neurogenesis following seizures but compromises survival of newborn neurons.Foundation for Science and Technology (FCT, Portugal); COMPETE; FEDER [PTDC/SAU-NEU/102612/2008, PTDC/NEU-OSD/0473/2012, PEst-C/SAU/LA0001/2013-2014, PEst-OE/EQB/LA0023/2013-2014]; FCT, Portugal [SFRH/BPD/78901/2011, SFRH/BD/77903/2011
Very Delayed Lupus Nephritis: a Report of Three Cases and Literature Review
Lupus nephritis (LN) affects up to 50% of patients with Systemic Lupus Erythematosus (SLE) and is associated with a worse prognosis. LN usually develops within the first 5 years of the onset of the disease. We report three patients with very delayed LN (DLN) diagnosed after 15 or more years after SLE diagnosis. The three patients were non-Caucasian women with adolescent or adult-onset SLE. Each had antinuclear, anti-dsDNA and anti-Ro antibodies. Hydroxychloroquine was prescribed for each. Their disease courses were characterised by sporadic non-renal flares controlled by steroids and, in two cases, by one cycle of rituximab. Unexpectedly, they developed proteinuria, haematuria and lowering of estimated glomerular filtration rate with clinical signs of renal disease. LN was confirmed by renal biopsy. Reviewing them, each showed serological signs of increasing disease activity (rising levels of anti-dsDNA antibodies and fall in C3) that predated clinical or laboratory signs of LN by 1-3 years. Reviewing the literature, we found a lack of knowledge about DLN starting more than 15 years after SLE diagnosis. With the increasing life expectancy of patients with SLE it is likely that more cases of very DLN will emerge.info:eu-repo/semantics/publishedVersio
Chronology of granitic structures in variscan "folded" granite associated to a shear zone (NW PORTUGAL)
Poster apresentado no 32nd International Geological Congress, Florença, Itália, 20-28 Agosto 2004
A Computer Simulation of the Nitinol Thermal Expansion under Fast Varying Working Conditions
We discuss the setup of a simulation on ANSYS to predict the thermal expansion of parts made of Nitinol. A simulation is justified for working conditions in which the part heating is not ho-mogeneous originating a temperature gradient across the part section such that an analytical estimate for the part expansion cannot be calculated. We apply the simulation to the topological optimization of a square section geometry and a bullet geometry for water assisted injection molding. For the topo-logical optimization we consider as parameter the wall thickness and consider both the cases of fast varying temperature and fast varying temperature and pressure.info:eu-repo/semantics/publishedVersio
EXFI: a low cost Fault Injection System for embedded Microprocessor-based Boards
Evaluating the faulty behavior of low-cost embedded microprocessor-based boards is an increasingly important issue, due to their adoption in many safety critical systems. The architecture of a complete Fault Injection environment is proposed, integrating a module for generating a collapsed list of faults, and another for performing their injection and gathering the results. To address this issue, the paper describes a software-implemented Fault Injection approach based on the Trace Exception Mode available in most microprocessors. The authors describe EXFI, a prototypical system implementing the approach, and provide data about some sample benchmark applications. The main advantages of EXFI are the low cost, the good portability, and the high efficienc
Estrutura e geoquímica das fases magmática e tardimagmática em zircões do maciço granítico de Peneda-Gerês (NW Península Ibérica)
Efectuou-se um estudo da estrutura interna e composição química dos zircões de granitos do maciço de Peneda-Gerês (granitos de Gerês, Paufito, Illa e Carris) com recurso a microscópio electrónico de varrimento (MEV) e microssonda electrónica. Este estudo permitiu caracterizar as fases magmática e tardimagmática e, ainda, constatar a existência de domínios de alteração nas zonas dos cristais mais ricas em elementos vestigiais (U, Th). Esta alteração é claramente mais expressiva nos zircões mais tardios (subtipos S5, G1) do granito de Carris e traduz-se em estruturas com forma botrioidal e de cor escura em imagem de electrões retrodifundidos (MEV).
A grande expressividade destes domínios de alteração nos zircões do granito de Carris, em constraste com a sua limitada expressividade em zircões dos restantes granitos do maciço de Peneda-Gerês, permite supor que este fenómeno de alteração esteja relacionado com a maior abundância de fluidos hidrotermais que afectaram domínios mais susceptíveis dos cristais de zircão. Refira-se que, espacialmente associados ao granito de Carris, ocorrem filões e filonetes quartzosos e quartzo-feldspáticos com mineralizações em volframite, molibdenite, pirite, etc, correspondendo às zonas mais mineralizadas do maciço de Peneda-Gerês.A study of the internal structure and chemical composition of zircon from the main granitic units of the Peneda-Gerês granitic massif (Gerês, Paufito, Illa and Carris granites) was
undertaken. This study permitted to
characterize the zircons’ magmatic and late
magmatic phases and, additionally, revealed
the existence of alteration domains in the
zones of the zircons which are richer in
trace elements (U, Th). This alteration is
notoriously more expressible in the late
crystallizing zircons (subtypes S5, G1) of theCarris granite and appears as botrioidal structures of dark colour in back scattered electron imagery (SEM).
The important expression of this alteration in the Carris granite, in contrast to the limited expression in zircons of the other granites, permits to envisage that this alteration is associated with a greater abundance of hydrothermal fluids that affected the more susceptible domains of the zircon crystals. It should be referred that spatially associated with the Carris granite occur quartz and quartz-feldspar veins with mineralizations of
wolframite, molybdenite, pyrite, etc, corresponding to the most mineralized zone of the Peneda-Gerês massif.Fundação para a Ciência e a Tecnologia (FCT) - Programa de Financiamento Plurianua
Cateterização venosa central guiada por ultrassom --- abordagem ‘‘Syringe-Free’’
Background and objectives
Central venous catheterization of the internal jugular vein is a commonly performed invasive procedure associated with a significant morbidity and even mortality. Ultrasound-guided methods have shown to significantly improve the success of the technique and are recommended by various scientific societies, including the American Society of Anesthesiologists. The aim of this report is to describe an innovative ultrasound-guided central line placement of the internal jugular vein.
Technique
The authors describe an innovative ultrasound-guided central line placement of the internal jugular vein based on an oblique approach – the “Syringe-Free” approach. This technique allows immediate progression of the guide wire in the venous lumen, while maintaining a real-time continuous ultrasound image.
Conclusions
The described method adds to the traditional oblique technique the possibility of achieving a continuous real-time ultrasound-guided venipuncture and a guide wire insertion that does not need removing the probe from the puncture field, while having a single operator performing the whole procedure
Nicorandil preserves the function of the mitochondrial phosphorylative and oxidative system in an animal model of global ischemia-reperfusion
Ischemia followed by reperfusion (IR) negatively affects mitochondrial function. At the level of the oxidative-phosphorylative system, IR inhibits the respiratory complexes and ATP synthase, and increases the passive leak of protons through the inner mitochondrial membrane, uncoupling respiration from phosphorylation, decreasing mitochondrial potential and, consequently, ATP production. Drugs that minimize the mitochondrial damage induced by IR may prove to be clinically effective. In the present work, we analyzed the impact of nicorandil, a mitochondrial ATP-sensitive potassium channel agonist, on mitochondrial dysfunction at the level of the oxidative-phosphorylative system of rat hearts subjected to IR. The decrease in the respiratory control ratio (RCR) induced by IR leads to the conclusion that IR has a negative impact on the activity of the mitochondrial respiratory system, uncoupling oxidation from phosphorylation. This effect is reversed by nicorandil, which increases not only RCR, but also the ADP/O ratio. Regarding respiratory rate, state 3 rate was approximately the same for all the experimental groups, while state 4 rate was lower for the group where IR was induced in the presence of nicorandil. This result is in accordance with the data obtained for the RCR and ADP/O. State 4 rate is most affected by uncoupling, given that it is controlled by proton leak. Mitochondria subjected to IR in the presence of nicorandil have a lower state 4 rate, i.e. they are less uncoupled. From these results we conclude that nicorandil preserves the function of mitochondria subjected to IR in terms of both respiration and phosphorylative capacity
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