962 resultados para Hébert, Chantal
Breakers of advanced glycation end products restore large artery properties in experimental diabetes
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Glucose and other reducing sugars react with proteins by a nonenzymatic, posttranslational modification process called nonenzymatic glycation. The formation of advanced glycation end products (AGEs) on connective tissue and matrix components accounts largely for the increase in collagen crosslinking that accompanies normal aging and which occurs at an accelerated rate in diabetes, leading to an increase in arterial stiffness. A new class of AGE crosslink “breakers” reacts with and cleaves these covalent, AGE-derived protein crosslinks. Treatment of rats with streptozotocin-induced diabetes with the AGE-breaker ALT-711 for 1–3 weeks reversed the diabetes-induced increase of large artery stiffness as measured by systemic arterial compliance, aortic impedance, and carotid artery compliance and distensibility. These findings will have considerable implications for the treatment of patients with diabetes-related complications and aging.
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The present study used functional magnetic resonance imaging to demonstrate that performance of visual spatial and visual nonspatial working memory tasks involve the same regions of the lateral prefrontal cortex when all factors unrelated to the type of stimulus material are appropriately controlled. These results provide evidence that spatial and nonspatial working memory may not be mediated, respectively, by mid-dorsolateral and mid-ventrolateral regions of the frontal lobe, as widely assumed, and support the alternative notion that specific regions of the lateral prefrontal cortex make identical executive functional contributions to both spatial and nonspatial working memory.
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The relative deficiency of T helper type 1 (Th1) and cytotoxic T lymphocyte (CTL) responses in early life is associated with an increased susceptibility to infections by intracellular microorganisms. This is likely to reflect a preferential polarization of immature CD4 T cells toward a Th2 rather than a Th1 pattern upon immunization with conventional vaccines. In this report, it is shown that a single immunization within the first week of life with DNA plasmids encoding viral (measles virus hemagglutinin, Sendai virus nucleoprotein) or bacterial (C fragment of tetanus toxin) vaccine antigens can induce adult-like Th1 or mixed Th1/Th2 responses indicated by production of IgG2a vaccine-specific antibodies and preferential secretion of interferon-γ (IFN-γ) compared with interleukin (IL)-5 by antigen-specific T cells, as well as significant CTL responses. However, in spite of this potent Th1-driving capacity, subsequent DNA immunization was not capable of reverting the Th2-biased responses induced after early priming with a recombinant measles canarypox vector. Thus, DNA vaccination represents a novel strategy capable of inducing Th1 or mixed Th1/Th2 and CTL responses in neonates and early life, providing it is performed prior to exposure to Th2-driving conventional vaccine antigens.
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Previous studies indicated that the central nervous system induces release of the cardiac hormone atrial natriuretic peptide (ANP) by release of oxytocin from the neurohypophysis. The presence of specific transcripts for the oxytocin receptor was demonstrated in all chambers of the heart by amplification of cDNA by the PCR using specific oligonucleotide primers. Oxytocin receptor mRNA content in the heart is 10 times lower than in the uterus of female rats. Oxytocin receptor transcripts were demonstrated by in situ hybridization in atrial and ventricular sections and confirmed by competitive binding assay using frozen heart sections. Perfusion of female rat hearts for 25 min with Krebs–Henseleit buffer resulted in nearly constant release of ANP. Addition of oxytocin (10−6 M) significantly stimulated ANP release, and an oxytocin receptor antagonist (10−7 and 10−6 M) caused dose-related inhibition of oxytocin-induced ANP release and in the last few minutes of perfusion decreased ANP release below that in control hearts, suggesting that intracardiac oxytocin stimulates ANP release. In contrast, brain natriuretic peptide release was unaltered by oxytocin. During perfusion, heart rate decreased gradually and it was further decreased significantly by oxytocin (10−6 M). This decrease was totally reversed by the oxytocin antagonist (10−6 M) indicating that oxytocin released ANP that directly slowed the heart, probably by release of cyclic GMP. The results indicate that oxytocin receptors mediate the action of oxytocin to release ANP, which slows the heart and reduces its force of contraction to produce a rapid reduction in circulating blood volume.
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Aldosterone-dependent epithelial sodium transport in the distal nephron is mediated by the absorption of sodium through the highly selective, amiloride-sensitive epithelial sodium channel (ENaC) made of three homologous subunits (α, β, and γ). In human, autosomal recessive mutations of α, β, or γENaC subunits cause pseudohypoaldosteronism type 1 (PHA-1), a renal salt-wasting syndrome characterized by severe hypovolemia, high plasma aldosterone, hyponatremia, life-threatening hyperkaliemia, and metabolic acidosis. In the mouse, inactivation of αENaC results in failure to clear fetal lung liquid at birth and in early neonatal death, preventing the observation of a PHA-1 renal phenotype. Transgenic expression of αENaC driven by a cytomegalovirus promoter in αENaC(−/−) knockout mice [αENaC(−/−)Tg] rescued the perinatal lethal pulmonary phenotype and partially restored Na+ transport in renal, colonic, and pulmonary epithelia. At days 5–9, however, αENaC(−/−)Tg mice showed clinical features of severe PHA-1 with metabolic acidosis, urinary salt-wasting, growth retardation, and 50% mortality. Adult αENaC(−/−)Tg survivors exhibited a compensated PHA-1 with normal acid/base and electrolyte values but 6-fold elevation of plasma aldosterone compared with wild-type littermate controls. We conclude that partial restoration of ENaC-mediated Na+ absorption in this transgenic mouse results in a mouse model for PHA-1.
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O conteúdo essencial na doutrina de Smend -- O conteúdo essencial na teoria de Düring -- Conteúdo essencial na teoria de Häbert -- A relativização dos direitos fundamentais
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Tissue kallikrein is a serine protease thought to be involved in the generation of bioactive peptide kinins in many organs like the kidneys, colon, salivary glands, pancreas, and blood vessels. Low renal synthesis and urinary excretion of tissue kallikrein have been repeatedly linked to hypertension in animals and humans, but the exact role of the protease in cardiovascular function has not been established largely because of the lack of specific inhibitors. This study demonstrates that mice lacking tissue kallikrein are unable to generate significant levels of kinins in most tissues and develop cardiovascular abnormalities early in adulthood despite normal blood pressure. The heart exhibits septum and posterior wall thinning and a tendency to dilatation resulting in reduced left ventricular mass. Cardiac function estimated in vivo and in vitro is decreased both under basal conditions and in response to βadrenergic stimulation. Furthermore, flow-induced vasodilatation is impaired in isolated perfused carotid arteries, which express, like the heart, low levels of the protease. These data show that tissue kallikrein is the main kinin-generating enzyme in vivo and that a functional kallikrein–kinin system is necessary for normal cardiac and arterial function in the mouse. They suggest that the kallikrein–kinin system could be involved in the development or progression of cardiovascular diseases.
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Members of hereditary nonpolyposis colon cancer (HNPCC) families harboring heterozygous germline mutations in the DNA mismatch repair genes hMSH2 or hMLH1 present with tumors generally two to three decades earlier than individuals with nonfamilial sporadic colon cancer. We searched for phenotypic features that might predispose heterozygous cells from HNPCC kindreds to malignant transformation. hMSH2+/− lymphoblastoid cell lines were found to be on average about 4-fold more tolerant than wild-type cells to killing by the methylating agent temozolomide, a phenotype that is invariably linked with impairment of the mismatch repair system. This finding was associated with an average 2-fold decrease of the steady-state level of hMSH2 protein in hMSH2+/− cell lines. In contrast, hMLH1+/− heterozygous cells were indistinguishable from normal controls in these assays. Thus, despite the fact that HNPCC families harboring mutations in hMSH2 or hMLH1 cannot be distinguished clinically, the early stages of the carcinogenic process in hMSH2 and hMLH1 mutation carriers may be different. Should hMSH2+/− colonocytes and lymphoblasts harbor a similar phenotype, the increased tolerance of the former to DNA-damaging agents present in the human colon may play a key role in the initiation of the carcinogenic process.
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Este artículo presenta un análisis de la noción de hegemonía tal como es desarrollada por Ernesto Laclau en investigaciones que comprenden desde trabajos previos a su clásico Hegemonía y estrategia socialista. Hacia una radicalización de la democracia (1985, en colaboración con Chantal Mouffe) hasta su obra importante más reciente La razón populista (2004). La hipótesis de lectura que guía el articulo es que hegemonía -desde sus orígenes en la teoría política de Laclau- funciona como una categoría que plantea la relación entre la universalidad y la particularidad pero también como tres conceptos -en tanto esta categoría adquiere un contenido particular cuando se la utiliza en diferentes campos: lo político y la lógica de constitución de lo social; el funcionamiento de una/la lógica de la política; y la constitución de las identidades colectivas
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"A través del peronismo llegué a comprender a Gramsci". Con esta frase, pronunciada por Ernesto Laclau en una entrevista concedida a una revista izquierdista estadounidense en 1983, se puede resumir lo que este politólogo argentino entendía como la vía más adecuada para alcanzar el poder político en un Estado, al menos a nivel de la capa conjuntiva (ejecutivo, legislativo y judicial) (Bueno, 1991). Junto a Laclau, en dicha entrevista, estaba su mujer, la también politóloga belga Chantal Mouffé. Ambos se encontraban en aquel año en París celebrando el centenario de la muerte de Carlos Marx. Estas palabras de Laclau fueron reproducidas en un artículo publicado en el diario El País del por Ludolfo Paramio (1983), sociólogo, periodista y físico español, militante del Partido Socialista Obrero Español (PSOE) desde 1982, adscrito durante una época a la corriente guerrista (de Alfonso Guerra), profesor de sociología en la Universidad Complutense de Madrid, entre otras, y Director del Departamento de Análisis y Estudios del Gabinete de la Presidencia del Gobierno de España en la primera legislatura de José Luis Rodríguez Zapatero, de 2004 a 2008. Además ha sido miembro de la Asociación Latinoamericana de Ciencia Política y dirige actualmente un postgrado sobre política en Iberoamérica en el Instituto Universitario de Investigación Ortega y Gasset. ¿Qué más tienen en común Laclau, Mouffé y Paramio además de esta interrelación ideológica, sentimental y periodística? Que no se puede entender Podemos sin estos tres nombres, como tampoco puede entenderse sin las conexiones ideológicas entre estos ideólogos y la propia familia de Pablo Manuel Iglesias Turrión (Pablo Iglesias II) y sus quehaceres político-vitales.
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Well-functioning factor markets are an essential condition for the competitiveness and sustainable development of agriculture and rural areas. At the same time, the functioning of the factor markets themselves is influenced by changes in agriculture and the rural economy. Such changes can be the result of progress in technology, globalisation and European market integration, changing consumer preferences and shifts in policy. Changes in the Common Agricultural Policy (CAP) over the last decade have particularly affected the rural factor markets. This book analyses the functioning of factor markets for agriculture in the EU-27 and several candidate countries. Written by leading academics and policy analysts from various European countries, these chapters compare the different markets, their institutional framework, their impact on agricultural development and structural change, and their interaction with the CAP. As the first comparative study to cover rural factor markets in Europe, highlighting their diversity − despite the Common Agricultural Policy and an integrated single market − Land, Labour & Capital Markets in European Agriculture provides a timely and valuable source of information at a time of further CAP reform and the continuing transformation of the EU's rural areas.
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This paper investigates the determinants of agricultural land price in several regions in France over the period 1994-2011, using individual plot transaction data, with a particular emphasis on agricultural subsidies and nitrate zoning regulations. It found a positive but relatively small capitalisation effect of the total subsidies per hectare. The data revealed that agricultural subsidies capitalised, at least to some extent, but the magnitude of such a capitalisation depends on the region considered, on the type of subsidy considered, and on the location of the plot in a nitrate surplus zone or not. Only land set-aside premiums significantly capitalise into land price, while single farm payments have a significant positive capitalisation impact only for plots located in a nitrate-surplus zone.
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Summary. In recent months, the migratory impacts of environmental degradation and climate change have gained increased worldwide attention. In response to the publication of the EC Staff Working Document on Climate Change, Environmental Degradation and Migration, this policy brief critically outlines current themes and issues that surround this global phenomenon, specifically the findings of current international research which frame the discussions on terminology and current legal, political and institutional conceptual debates. Several proposals were put forward during a Policy Forum in January 2013. Firstly, there is a need for tailored and actionable research outputs that take into account political pressures and realities on the ground. Secondly, migration and climate policies would be clearly boosted through the elaboration of a common policy-oriented research agenda of which elements were put forward at the event. Finally, efficient communication tools and channels could be developed to transfer research findings to policy-makers.
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Leishmaniaparasites cause a broad range of disease, with cutaneous afflictions being, by far, the most prevalent. Variations in disease severity and symptomatic spectrum are mostly associated to parasite species. One risk factor for the severity and emergence of leishmaniasis is immunosuppression, usually arising by coinfection of the patient with human immunodeficiency virus (HIV). Interestingly, several species ofLeishmaniahave been shown to bear an endogenous cytoplasmic dsRNA virus (LRV) of theTotiviridaefamily, and recently we correlated the presence of LRV1 withinLeishmaniaparasites to an exacerbation murine leishmaniasis and with an elevated frequency of drug treatment failures in humans. This raises the possibility of further exacerbation of leishmaniasis in the presence of both viruses, and here we report a case of cutaneous leishmaniasis caused byLeishmania braziliensisbearing LRV1 with aggressive pathogenesis in an HIV patient. LRV1 was isolated and partially sequenced from skin and nasal lesions. Genetic identity of both sequences reinforced the assumption that nasal parasites originate from primary skin lesions. Surprisingly, combined antiretroviral therapy did not impact the devolution ofLeishmaniainfection. TheLeishmaniainfection was successfully treated through administration of liposomal amphotericin B.