115 resultados para Content-independent embedding
Resumo:
Transcription factors of the NF-kappaB/Rel family are important mediators of extracellular signals. Their implication in positive selection of thymocytes is suggested by a defective thymic development in transgenic mice that over-express IkappaB in thymocytes. These mice exhibit an accumulation of an unusually prominent population of TCRhigh/CD4/CD8 double positive cells in the thymus and a dramatic reduction of CD4+ and CD8+ cells in the periphery. The present study addresses the role of NF-kappaB in survival and differentiation processes of maturing thymocytes using IkappaB/bcl-2 and IkappaB/HY double-transgenic mice. Neither the introduction of the anti-apoptosis gene bcl-2 nor the positively selecting background in female HY transgenic mice resulted in a rescue of the maturational defects observed in the thymus of IkappaB transgenic mice. Thus, rather than promoting survival the main role of NF-kappaB/Rel proteins during positive selection of thymocytes appears to be the mediation of differentiation signals.
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We have explored in vitro the mechanism by which human immunodeficiency virus, type 1 (HIV-1) induces cell death of primary CD4+ T cells in conditions of productive infection. Although HIV-1 infection primed phytohemagglutinin-activated CD4+ T cells for death induced by anti-CD95 antibody, T cell death was not prevented by a CD95-Fc decoy receptor, nor by decoy receptors of other members of the TNFR family (TNFR1/R2, TRAILR1/R2/OPG, TRAMP) or by various blocking antibodies, suggesting that triggering of death receptors by their cognate ligands is not involved in HIV-induced CD4 T cell death. HIV-1 induced CD4 T cell shrinkage, cell surface exposure of phosphatidylserine, loss of mitochondrial membrane potential (Deltapsim), and mitochondrial release of cytochrome c and apoptosis-inducing factor. A typical apoptotic phenotype (nuclear chromatin condensation and fragmentation) only occurred in around half of the dying cells. Treatment with benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, a broad spectrum caspase inhibitor, prevented nuclear chromatin condensation and fragmentation in HIV-infected CD4+ T cells and in a cell-free system (in which nuclei were incubated with cytoplasmic extracts from the HIV-infected CD4+ T cells). Nevertheless, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone did not prevent mitochondrial membrane potential loss and cell death, suggesting that caspases are dispensable for HIV-mediated cell death. Our findings suggest a major role of the mitochondria in the process of CD4 T cell death induced by HIV, in which targeting of Bax to the mitochondria may be involved.
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It has been demonstrated in earlier studies that patients with a cochlear implant have increased abilities for audio-visual integration because the crude information transmitted by the cochlear implant requires the persistent use of the complementary speech information from the visual channel. The brain network for these abilities needs to be clarified. We used an independent components analysis (ICA) of the activation (H2 (15) O) positron emission tomography data to explore occipito-temporal brain activity in post-lingually deaf patients with unilaterally implanted cochlear implants at several months post-implantation (T1), shortly after implantation (T0) and in normal hearing controls. In between-group analysis, patients at T1 had greater blood flow in the left middle temporal cortex as compared with T0 and normal hearing controls. In within-group analysis, patients at T0 had a task-related ICA component in the visual cortex, and patients at T1 had one task-related ICA component in the left middle temporal cortex and the other in the visual cortex. The time courses of temporal and visual activities during the positron emission tomography examination at T1 were highly correlated, meaning that synchronized integrative activity occurred. The greater involvement of the visual cortex and its close coupling with the temporal cortex at T1 confirm the importance of audio-visual integration in more experienced cochlear implant subjects at the cortical level.
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This research investigates differences in the stereotype content of immigrant groups between linguistic regions. We expected that immigrant groups who speak the local language of a specific linguistic region would be perceived as more competitive within this region than in another linguistic region. Further, we expected these differences would underlie regional differences in stereotype content, albeit only for the warmth dimension. Predictions were tested in the two largest linguistic regions of Switzerland. As expected, in the German-speaking region, locals perceived German immigrants as more competitive and thus as less warm, whereas in the French-speaking region, locals perceived French immigrants as more competitive and, consequently, as less warm. So, paradoxically, immigrants with strong integration potential are particularly disliked because they are regarded as direct competitors.
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Exercise is known to reduce cardiovascular risk. However, its role on atherosclerotic plaque stabilization is unknown. Apolipoprotein E(-/-) mice with vulnerable (2-kidney, 1-clip: angiotensin [Ang] II-dependent hypertension model) or stable atherosclerotic plaques (1-kidney, 1-clip: Ang II-independent hypertension model and normotensive shams) were used for experiments. Mice swam regularly for 5 weeks and were compared with sedentary controls. Exercised 2-kidney, 1-clip mice developed significantly more stable plaques (thinner fibrous cap, decreased media degeneration, layering, macrophage content, and increased smooth muscle cells) than sedentary controls. Exercise did not affect blood pressure. Conversely, swimming significantly reduced aortic Ang II type 1 receptor mRNA levels, whereas Ang II type 2 receptor expression remained unaffected. Sympathetic tone also significantly diminished in exercised 2-kidney, 1-clip mice compared with sedentary ones; renin and aldosterone levels tended to increase. Ang II type 1 downregulation was not accompanied by improved endothelial function, and no difference in balance among T-helper 1, T-helper 2, and T regulatory cells was observed between sedentary and exercised mice. These results show for the first time, in a mouse model of Ang II-mediated vulnerable plaques, that swimming prevents atherosclerosis progression and plaque vulnerability. This benefit is likely mediated by downregulating aortic Ang II type 1 receptor expression independent from any hemodynamic change. Ang II type 1 downregulation may protect the vessel wall from the Ang II proatherogenic effects. Moreover, data presented herein further emphasize the pivotal and blood pressure-independent role of Ang II in atherogenesis.
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BACKGROUND: Prognosis of status epilepticus (SE) depends on its cause, but there is uncertainty as to whether SE represents an independent outcome predictor for a given etiology. Cerebral anoxia is a relatively homogenous severe encephalopathy. Postanoxic SE is associated to a nearly 100% mortality in this setting; however, it is still unclear whether this is a severity marker of the underlying encephalopathy, or an independent factor influencing outcome. The goal of this study was to assess if postanoxic SE is independently associated with mortality after cerebral anoxia. METHODS: This was a retrospective observation of consecutive comatose survivors of cardiac arrest, including subjects treated with hypothermia. On the subgroup with EEG recordings in the first hospitalization days, univariate and multivariate analyses were applied to potential determinants of in-hospital mortality, and included the following variables: age, gender, type and length of cardiac arrest, occurrence of circulatory shock, presence of therapeutic hypothermia, and electrographic SE. RESULTS: Out of 166 postanoxic patients, 107 (64%) had an EEG (median latency from admission, 2 days); in this group, therapeutic hypothermia was administered in 59%. Death occurred in 71 (67%) patients. Postanoxic SE was associated with mortality regardless of type of acute cardiac rhythm and administration of hypothermic treatment. CONCLUSION: In this hospital-based cohort, postanoxic status epilepticus (SE) seems to be independently related to death in cardiac arrest survivors, suggesting that SE might determine a bad prognosis for a given etiology. Confirmation of these results in a prospective assessment is needed.
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Time-lapse geophysical data acquired during transient hydrological experiments are being increasingly employed to estimate subsurface hydraulic properties at the field scale. In particular, crosshole ground-penetrating radar (GPR) data, collected while water infiltrates into the subsurface either by natural or artificial means, have been demonstrated in a number of studies to contain valuable information concerning the hydraulic properties of the unsaturated zone. Previous work in this domain has considered a variety of infiltration conditions and different amounts of time-lapse GPR data in the estimation procedure. However, the particular benefits and drawbacks of these different strategies as well as the impact of a variety of key and common assumptions remain unclear. Using a Bayesian Markov-chain-Monte-Carlo stochastic inversion methodology, we examine in this paper the information content of time-lapse zero-offset-profile (ZOP) GPR traveltime data, collected under three different infiltration conditions, for the estimation of van Genuchten-Mualem (VGM) parameters in a layered subsurface medium. Specifically, we systematically analyze synthetic and field GPR data acquired under natural loading and two rates of forced infiltration, and we consider the value of incorporating different amounts of time-lapse measurements into the estimation procedure. Our results confirm that, for all infiltration scenarios considered, the ZOP GPR traveltime data contain important information about subsurface hydraulic properties as a function of depth, with forced infiltration offering the greatest potential for VGM parameter refinement because of the higher stressing of the hydrological system. Considering greater amounts of time-lapse data in the inversion procedure is also found to help refine VGM parameter estimates. Quite importantly, however, inconsistencies observed in the field results point to the strong possibility that posterior uncertainties are being influenced by model structural errors, which in turn underlines the fundamental importance of a systematic analysis of such errors in future related studies.
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Diagnosis of several neurological disorders is based on the detection of typical pathological patterns in the electroencephalogram (EEG). This is a time-consuming task requiring significant training and experience. Automatic detection of these EEG patterns would greatly assist in quantitative analysis and interpretation. We present a method, which allows automatic detection of epileptiform events and discrimination of them from eye blinks, and is based on features derived using a novel application of independent component analysis. The algorithm was trained and cross validated using seven EEGs with epileptiform activity. For epileptiform events with compensation for eyeblinks, the sensitivity was 65 +/- 22% at a specificity of 86 +/- 7% (mean +/- SD). With feature extraction by PCA or classification of raw data, specificity reduced to 76 and 74%, respectively, for the same sensitivity. On exactly the same data, the commercially available software Reveal had a maximum sensitivity of 30% and concurrent specificity of 77%. Our algorithm performed well at detecting epileptiform events in this preliminary test and offers a flexible tool that is intended to be generalized to the simultaneous classification of many waveforms in the EEG.
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Objective: Converging evidence speak in favor of an abnormal susceptibility to oxidative stress in schizophrenia. A decreased level of glutathione (GSH), the principal non-protein antioxidant and redox regulator, was observed both in cerebrospinal-fluid and prefrontal cortex of schizophrenia patients (Do et al., 2000). Results: Schizophrenia patients have an abnormal GSH synthesis most likely of genetic origin: Two independent case-control studies showed a significant association between schizophrenia and a GAG trinucleotide repeat (TNR) polymorphism in the GSH key synthesizing enzyme glutamate-cysteine-ligase (GCL) catalytic subunit (GCLC) gene. The most common TNR genotype 7/7 was more frequent in controls, whereas the rarest TNR genotype 8/8 was three times more frequent in patients. The disease-associated genotypes correlated with a decrease in GCLC protein expression, GCL activity and GSH content. Such a redox dysregulation during development could underlie the structural and functional anomalies in connectivity: In experimental models, GSH deficit induced anomalies similar to those observed in patients. (a) morphology: In animal models with GSH deficit during the development we observed in prefrontal cortex a decreased dendritic spines density in pyramidal cells and an abnormal development of parvalbumine (but not of calretinine) immunoreactive GABA interneurones in anterior cingulate cortex. (b) physiology: GSH depletion in hippocampal slices induces NMDA receptors hypofunction and an impairment of long term potentiation. In addition, GSH deficit affected the modulation of dopamine on NMDA-induced Ca 2+ response in cultured cortical neurons. While dopamine enhanced NMDA responses in control neurons, it depressed NMDA responses in GSH-depleted neurons. Antagonist of D2-, but not D1-receptors, prevented this depression, a mechanism contributing to the efficacy of antipsychotics. The redox sensitive ryanodine receptors and L-type calcium channels underlie these observations. (c) cognition: Developing rats with low [GSH] and high dopamine lead deficit in olfactory integration and in object recognition which appears earlier in males that females, in analogy to the delay of the psychosis onset between man and woman. Conclusion: These clinical and experimental evidence, combined with the favorable outcome of a clinical trial with N-Acetyl Cysteine, a GSH precursor, on both the negative symptoms (Berk et al., submitted) and the mismatch negativity in an auditory oddball paradigm supported the proposal that a GSH synthesis impairment of genetic origin represent, among other factors, one major risk factor in schizophrenia.
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IL-6 plays a central role in supporting pathological TH2 and TH17 cell development and inhibiting the protective T regulatory cells in allergic asthma. TH17 cells have been demonstrated to regulate allergic asthma in general and T-bet-deficiency-induced asthma in particular. Here we found an inverse correlation between T-bet and Il-6 mRNA expression in asthmatic children. Moreover, experimental subcutaneous immunotherapy (SIT) in T-bet((-/-)) mice inhibited IL-6, IL-21R and lung TH17 cells in a setting of asthma. Finally, local delivery of an anti-IL-6R antibody in T-bet((-/-)) mice resulted in the resolution of this allergic trait. Noteworthy, BATF, crucial for the immunoglobulin-class-switch and TH2,TH17 development, was found down-regulated in the lungs of T-bet((-/-)) mice after SIT and after treatment with anti-IL-6R antibody, indicating a critical role of IL-6 in controlling BATF/IRF4 integrated functions in TH2, TH17 cells and B cells also in a T-bet independent fashion in allergic asthma.
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The Spanish judicial system is independent and headed by the Supreme Court. Spain has a civil law system. The criminal procedure is governed by the legality principle--by opposition to the opportunity or expediency principle--which implies that prosecution must take place in all cases in which sufficient evidence exists of guilt. Traditionally, the role of the PPS in Spain has been very limited during the investigative stage of the process. That stage is under the responsibility of the Examining Magistrate (EM). Since the end of the 1980s, a series of modifications has been introduced in order to extend the functions of the PPS. In 1988, the PPS received extended competences which allow them to receive reports of offenses. Upon knowing of an offense (reported or known to have been committed), the PPS can initiate the criminal proceeding. The PPS is also allowed to lead a sort of plea bargain under a series of restrictive conditions and only for some offenses. At the same time, the PPS received extended competences in the juvenile justice criminal proceeding in 2000. With all this said, the role of the PPS has not changed radically and, during the investigative stage of the process, their main role remains the presentation of the accusation, playing a more active role during the trial stage of the proceeding. In this article the national criminal justice system of Spain is described. Special attention is paid to the function of the PPS within this framework and its relationship to police and courts. The article refers to legal provisions and the factual handling of criminal cases.
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Modern dietary habits are characterized by high-sodium and low-potassium intakes, each of which was correlated with a higher risk for hypertension. In this study, we examined whether long-term variations in the intake of sodium and potassium induce lasting changes in the plasma concentration of circulating steroids by developing a mathematical model of steroidogenesis in mice. One finding of this model was that mice increase their plasma progesterone levels specifically in response to potassium depletion. This prediction was confirmed by measurements in both male mice and men. Further investigation showed that progesterone regulates renal potassium handling both in males and females under potassium restriction, independent of its role in reproduction. The increase in progesterone production by male mice was time dependent and correlated with decreased urinary potassium content. The progesterone-dependent ability to efficiently retain potassium was because of an RU486 (a progesterone receptor antagonist)-sensitive stimulation of the colonic hydrogen, potassium-ATPase (known as the non-gastric or hydrogen, potassium-ATPase type 2) in the kidney. Thus, in males, a specific progesterone concentration profile induced by chronic potassium restriction regulates potassium balance.
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The investigation of gender differences in emotion has attracted much attention given the potential ramifications on our understanding of sexual differences in disorders involving emotion dysregulation. Yet, research on content-specific gender differences across adulthood in emotional responding is lacking. The aims of the present study were twofold. First, we sought to investigate to what extent gender differences in the self-reported emotional experience are content specific. Second, we sought to determine whether gender differences are stable across the adult lifespan. We assessed valence and arousal ratings of 14 picture series, each of a different content, in 94 men and 118 women aged 20 to 81. Compared to women, men reacted more positively to erotic images, whereas women rated low-arousing pleasant family scenes and landscapes as particularly positive. Women displayed a disposition to respond with greater defensive activation (i.e., more negative valence and higher arousal), in particular to the most arousing unpleasant contents. Importantly, significant interactions between gender and age were not found for any single content. This study makes a novel contribution by showing that gender differences in the affective experiences in response to different contents persist across the adult lifespan. These findings support the "stability hypothesis" of gender differences across age.
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Fas ligand (FasL) causes apoptosis of epidermal keratinocytes and triggers the appearance of spongiosis in eczematous dermatitis. We demonstrate here that FasL also aggravates inflammation by triggering the expression of proinflammatory cytokines, chemokines, and adhesion molecules in keratinocytes. In HaCaT cells and in reconstructed human epidermis (RHE), FasL triggered a NF-kappaB-dependent mRNA accumulation of inflammatory cytokines (tumor necrosis factor-alpha, IL-6, and IL-1beta), chemokines (CCL2/MCP-1, CXCL1/GROalpha, CXCL3/GROgamma, and CXCL8/IL-8), and the adhesion molecule ICAM-1. Oligomerization of Fas was required both for apoptosis and for gene expression. Inhibition of caspase activity abolished FasL-dependent apoptosis; however, it failed to suppress the expression of FasL-induced genes. Additionally, in the presence of caspase inhibitors, but not in their absence, FasL triggered the accumulation of CCL5/RANTES (regulated on activation normal T cell expressed and secreted) mRNA. Our findings identify a novel proinflammatory role of FasL in keratinocytes that is independent of caspase activity and is separable from apoptosis. Thus, in addition to causing spongiosis, FasL may play a direct role in triggering and/or sustaining inflammation in eczemas.