965 resultados para Pathologies neurodégénératives


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Os suplementos alimentares para emagrecer são um apelo irresistível para quem procura uma forma de perder peso “sem sacrifícios” e “sem esforço”. Com efeito, estamos perante um mercado sazonal em expansão em que a menção “natural” parece tranquilizar os consumidores esquecendo que a eficácia e segurança destes produtos necessita ser avaliada. Nesse contexto, o presente estudo teve como objetivo efetuar a caraterização dos consumidores de suplementos alimentares para emagrecer, da zona centro de Portugal, avaliar o seu grau de satisfação com os produtos e ainda o possível risco que envolve o consumo destes produtos sobretudo quando ingeridos concomitantemente com medicamentos. Recorreu-se a um questionário anónimo, confidencial e de preenchimento voluntário, distribuído em farmácias, parafarmácias e dietéticas e/ou ervanárias maioritariamente do concelho de Viseu e Figueira da Foz. A recolha dos dados decorreu entre os meses de abril e julho de 2014. E tinha como critérios de inclusão ser maior de 18 anos, ambos os sexos e saber ler e escrever. Acorreram 304 indivíduos. A análise dos dados foi feita recorrendo a testes estatísticos adequados a cada caso. O presente estudo ao caracterizar o perfil de consumidores de suplementos alimentares encontrou uma população, maioritariamente feminina (88,5%) com grau de instrução elevado, secundário e superior, nas faixas etária dos 25-44 anos (59,4%), casados ou em união de facto. Apresentavam excesso de peso e obesidade (54%), sem hábitos de prática de exercício físico e com alimentação desequilibrada. Estes preferem adquirir os suplementos alimentares para emagrecer nas farmácias embora a decisão de consumir estes produtos seja pessoal (32,7%). Para aconselhamento preferem o farmacêutico (17,6%) e apenas 4,2% recorrem ao médico. Revelaram ainda consumir estes produtos por um período de tempo limitado, entre 1-3 meses e estarem satisfeitos com os resultados obtidos após o consumo de suplementos alimentares (63,1%). Constituindo os efeitos secundários dos suplementos alimentares uma preocupação legítima verificamos que a maioria dos inquiridos (93,3%) não refere qualquer efeito indesejável, os restantes indivíduos que revelaram aparecimento de ações indesejáveis disseram ter-se dirigido ao farmacêutico para reportar a situação. As patologias com maior prevalência entre os consumidores foram doenças endócrinas, nutricionais e metabólicas, seguida das perturbações mentais e comportamentais e por fim as doenças cardiovasculares a que correspondem os principais grupos terapêuticos encontrados: psicofármacos, medicamentos usados em patologias do sistema endócrino e antihipertensores. Cerca de 25,8% dos inquiridos que consumiam suplementos alimentares para emagrecer utilizavam concomitantemente estes fármacos. A análise dos cinco suplementos alimentares para emagrecer maioritariamente consumidos pela amostra (57,8%) evidenciou a existência de possíveis interações com os grupos de fármacos mais utilizados. Os resultados obtidos mostram por um lado, a necessidade de esclarecer o conceito de que nem tudo o que é natural é inócuo e por outro lado, ressaltam a importância no ato de venda do aconselhamento individual, adaptado a cada consumidor (com ou sem medicação), por um profissional de saúde com conhecimentos no âmbito da gestão e fisiologia de peso corporal e conhecimento sólido sobre a eficácia e segurança destes suplementos.

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Le co-transporteur KCC2 spécifique au potassium et chlore a pour rôle principal de réduire la concentration intracellulaire de chlore, entraînant l’hyperpolarisation des courants GABAergic l’autorisant ainsi à devenir inhibiteur dans le cerveau mature. De plus, il est aussi impliqué dans le développement des synapses excitatrices, nommées aussi les épines dendritiques. Le but de notre projet est d’étudier l’effet des modifications concernant l'expression et la fonction de KCC2 dans le cortex du cerveau en développement dans un contexte de convulsions précoces. Les convulsions fébriles affectent environ 5% des enfants, et ce dès la première année de vie. Les enfants atteints de convulsions fébriles prolongées et atypiques sont plus susceptibles à développer l’épilepsie. De plus, la présence d’une malformation cérébrale prédispose au développement de convulsions fébriles atypiques, et d’épilepsie du lobe temporal. Ceci suggère que ces pathologies néonatales peuvent altérer le développement des circuits neuronaux irréversiblement. Cependant, les mécanismes qui sous-tendent ces effets ne sont pas encore compris. Nous avons pour but de comprendre l'impact des altérations de KCC2 sur la survenue des convulsions et dans la formation des épines dendritiques. Nous avons étudié KCC2 dans un modèle animal de convulsions précédemment validé, qui combine une lésion corticale à P1 (premier jour de vie postnatale), suivie d'une convulsion induite par hyperthermie à P10 (nommés rats LHS). À la suite de ces insultes, 86% des rats mâles LHS développent l’épilepsie à l’âge adulte, au même titre que des troubles d’apprentissage. À P20, ces animaux presentent une augmentation de l'expression de KCC2 associée à une hyperpolarisation du potentiel de réversion de GABA. De plus, nous avons observé des réductions dans la taille des épines dendritiques et l'amplitude des courants post-synaptiques excitateurs miniatures, ainsi qu’un déficit de mémoire spatial, et ce avant le développement des convulsions spontanées. Dans le but de rétablir les déficits observés chez les rats LHS, nous avons alors réalisé un knock-down de KCC2 par shARN spécifique par électroporation in utero. Nos résultats ont montré une diminution de la susceptibilité aux convulsions due à la lésion corticale, ainsi qu'une restauration de la taille des épines. Ainsi, l’augmentation de KCC2 à la suite d'une convulsion précoce, augmente la susceptibilité aux convulsions modifiant la morphologie des épines dendritiques, probable facteur contribuant à l’atrophie de l’hippocampe et l’occurrence des déficits cognitifs. Le deuxième objectif a été d'inspecter l’effet de la surexpression précoce de KCC2 dans le développement des épines dendritiques de l’hippocampe. Nous avons ainsi surexprimé KCC2 aussi bien in vitro dans des cultures organotypiques d’hippocampe, qu' in vivo par électroporation in utero. À l'inverse des résultats publiés dans le cortex, nous avons observé une diminution de la densité d’épines dendritiques et une augmentation de la taille des épines. Afin de confirmer la spécificité du rôle de KCC2 face à la région néocorticale étudiée, nous avons surexprimé KCC2 dans le cortex par électroporation in utero. Cette manipulation a eu pour conséquences d’augmenter la densité et la longueur des épines synaptiques de l’arbre dendritique des cellules glutamatergiques. En conséquent, ces résultats ont démontré pour la première fois, que les modifications de l’expression de KCC2 sont spécifiques à la région affectée. Ceci souligne les obstacles auxquels nous faisons face dans le développement de thérapie adéquat pour l’épilepsie ayant pour but de moduler l’expression de KCC2 de façon spécifique.

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Thesis (Ph.D.)--University of Washington, 2016-06

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Thesis (Ph.D.)--University of Washington, 2016-06

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Changes in gene expression are associated with switching to an autoprotected phenotype in response to environmental and physiological stress. Ubiquitous molecular chaperones from the heat shock protein (HSP) superfamily confer neuronal protection that can be blocked by antibodies. Recent research has focused on the interactions between the molecular sensors that affect the increased expression of neuroprotective HSPs above constitutive levels. An examination of the conditions under which the expression of heat shock protein 70 (Hsp70) was up regulated in a hypoxia and anoxia tolerant tropical species, the epaulette shark (Hemiscyllium ocellatum), revealed that up-regulation was dependent on exceeding a stimulus threshold for an oxidative stressor. While hypoxic-preconditioning confers neuroprotective changes, there was no increase in the level of Hsp70 indicating that its increased expression was not associated with achieving a neuroprotected state in response to hypoxia in the epaulette shark. Conversely, there was a significant increase in Hsp70 in response to anoxic-preconditioning, highlighting the presence of a stimulus threshold barrier and raising the possibility that, in this species, Hsp70 contributes to the neuroprotective response to extreme crises, such as oxidative stress. Interestingly, there was a synergistic effect of coincident stressors on Hsp70 expression, which was revealed when metabolic stress was superimposed upon oxidative stress. Brain energy charge was significantly lower when adenosine receptor blockade, provided by treatment with aminophylline, was present prior to the final anoxic episode, under these circumstances, the level of Hsp70 induced was significantly higher than in the pair-matched saline treated controls. An understanding of the molecular and metabolic basis for neuroprotective switches, which result in an up-regulation of neuroprotective Hsp70 expression in the brain, is needed so that intervention strategies can be devised to manage CNS pathologies and minimise damage caused by ischemia and trauma. In addition, the current findings indicate that measurements of HSP expression per se may provide a useful correlate of the level of neuroprotection achieved in the switch to an autoprotected phenotype.

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Purpose. The ability to sense the position of limb segments is a highly specialised proprioceptive function important for control of movement. Abnormal knee proprioception has been found in association with several musculoskeletal pathologies but whether nociceptive Stimulation can produce these proprioceptive changes is unclear. This study evaluated the effect of experimentally induced knee pain on knee joint position sense (JPS) in healthy individuals. Study design. Repeated measures, within-subject design. Methods. Knee JPS was tested in 16 individuals with no history of knee pathology under three experimental conditions: baseline control, a distraction task and knee pain induced by injection of hypertonic saline into the infrapatellar fat pad. Knee JPS was measured using active ipsilateral limb matching responses at 20degrees and 60degrees flexion whilst non-weightbearing (NWB) and 20degrees flexion single leg stance. During the tasks, the subjective perception of distraction and severity of pain were measured using 11-point numerical rating scales. Results. Knee JPS was not altered by acute knee pain in any of the positions tested. The distraction task resulted in poorer concentration, greater JPS absolute errors at 20degrees NWB, and greater variability in errors during the WB tests. There were no significant correlations between levels of pain and changes in JPS errors. Changes in JPS with pain and distraction were inversely related to baseline knee JPS variable error in all test positions (r = -0.56 to -0.91) but less related to baseline absolute error. Conclusion. Knee JPS is reduced by an attention-demanding task but not by experimentally induced pain. (C) 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.

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Elevated extracellular concentrations of the neurotransmitter glutamate are neurotoxic and directly contribute to CNS damage as a result of ischemic pathologies. However, the main contributors to this uncontrolled rise in glutamate are still unconfirmed. It has been reported that the reversal of high-affinity glutamate transporters is a significant contributing factor. Conversely, it has also Peen observed that these transporters continue to take up glutamate, albeit at a reduced saturation concentration, under ischemic conditions. We sought to determine whether glutamate transporters continue to remove glutamate from the extracellular space under ischemic conditions by pharmacologically modulating the activity of high-affinity retinal glutamate transporters during simulated ischemia in vitro. Retinal glutamate transporter activity was significantly reduced under these ischemic conditions. The suppression of retinal glutamate transporter activity, with the protein kinase C inhibitor chelerythrine, significantly reduced ischemic glutamate uptake and enhanced retinal neurodegeneration. These findings imply a limited but protective role for retinal glutamate transporters under certain ischemic conditions, suggesting that pharmacological enhancement of high-affinity glutamate transporter activity may reduce tissue damage and loss of function resulting from toxic extracellular glutamate concentrations. (C) 2004 Wiley-Liss, Inc.

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Environmentally-related wear conditions and pathologies affecting the dentition of fossil lungfish from freshwater deposits in Australia have been analysed and compared with similar changes in the dentition of the living Australian lungfish, Neoceratodus forsteri. Fossil populations from the Namba, Etadunna, Wipajiri and Katipiri formations in central Australia, and the Carl Creek Limestone and the Camfield beds in northern Australia were assessed. Tooth plates from populations of living lungfish from the Brisbane River and Enoggera Reservoir in southeast Queensland were analysed for comparison. Tooth plates were measured to determine the numbers of different age groups in each population. They were assessed for abrasion, attrition, spur and step wear, erosion and caries, and for trauma and pathological conditions such as malocclusion, hyperplasia, abscesses, osteopenia and parasitic damage. All of these conditions are related to the environment where the fish lived, are found in living members of the group, and can be compared directly with those of fossil relatives. The results suggest that some of the fossil populations were at risk before climatic changes late in the Cainozoic destroyed their habitats. Some fossil lungfish populations, such as those of the Wipajiri Formation, exhibit active spawning and recruitment, good growth rates and a low incidence of disease and environmentally related damage to the tooth plates. Others, like those of the Katipiri and Namba Formations, include no young, and the adult fish were ageing and show environmentally-related damage to the dentition. Etadunna lungfish had active recruitment, but the tooth plates show a high incidence of attrition and caries. Riversleigh lungfish were actively spawning but did not grow large. Tooth plates from this latter deposit have a high incidence of pathological conditions. Fish from the Camfield Beds, where food was severely limiting, had little serious pathology but high levels of caries. Pathologies among living lungfish are common, but fossil fish were comparatively healthy, with few serious dental problems. Information from studies of fossil lungfish confirms that conservation of the few living species of lungfish depends on the maintenance of clean environments that provide adequate supplies of food and suitable sites for spawning and for the growth of young fish.

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Obesity and the metabolic syndrome have both reached pandemic proportions. Together they have the potential to impact on the incidence and severity of cardiovascular pathologies, with grave implications for worldwide health care systems. The metabolic syndrome is characterized by visceral obesity, insulin resistance, hypertension, chronic inflammation, and thrombotic disorders contributing to endothelial dysfunction and, subsequently, to accelerated atherosclerosis. Obesity is a key component in development of the metabolic syndrome and it is becoming increasingly clear that a central factor in this is the production by adipose cells of bioactive substances that directly influence insulin sensitivity and vascular injury. In this paper, we review advances in the understanding of biologically active molecules collectively referred to as adipokines and how dysregulated production of these factors in obese states mediates the pathogenesis of obesity associated metabolic syndrome.

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The prevalence of tumours of the germ line is increasing in the male population. This complex disease has a complex aetiology. We examine the contribution of genetic mutations to the development of germ line tumours in this review. In particular, we concentrate on fly and mouse experimental systems in order to demonstrate that mutations in some conserved genes cause pathologies typical of certain human germ cell tumours, whereas other mutations elicit phenotypes that are unique to the experimental model. Despite these experimental systems being imperfect, we show that they are useful models of human testicular germ cell tumourigenesis.

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In recent years, the multiparametric approach for evaluating perceptual rating of voice quality has been advocated. This study evaluates the accuracy of predicting perceived overall severity of voice quality with a minimal set of aerodynamic, voice range profile (phonetogram), and acoustic perturbation measures. One hundred and twelve dysphonic persons (93 women and 19 men) with laryngeal pathologies and 41 normal controls (35 women and six men) with normal voices participated in this study. Perceptual severity judgement was carried out by four listeners rating the G (overall grade) parameter of the GRBAS scale.(1) The minimal set of instrumental measures was selected based on the ability of the measure to discriminate between dysphonic and normal voices, and to attain at least a moderate correlation with perceived overall severity. Results indicated that perceived overall severity was best described by maximum phonation time of sustained /a/, peak intraoral pressure of the consonant-vowel /pi/ strings production, voice range profile area, and acoustic jitter. Direct-entry discriminant function analysis revealed that these four voice measures in combination correctly predicted 67.3% of perceived overall severity levels.

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The lexical-semantic and syntactic abilities of a group of individuals with chronic nonthalamic subcortical (NS) lesions following stroke (n = 6) were investigated using the Western Aphasia Battery (WAB) picture description task [Kertesz, A. (1982). The Western aphasia battery. New York: Grune and Stratton] and compared with those of a group of subjects with Huntington's Disease (HD) (n = 6) and a nonneurologically impaired control group (n = 6) matched for age, sex, and educational level. The performance of the NS and HD subjects did not differ significantly from the well controls on measures of lexical-semantic abilities. NS and HD subjects provided as much information about the target picture as control subjects, but produced fewer action information units. Analysis of syntactic abilities revealed that the HD subjects produced significantly more grammatical errors than both the NS and control subjects and that the NS group performed in a similar manner to control subjects. These findings are considered in terms of current theories of subcortical language function Learning outcomes: As a result of this activity, the reader will obtain information about the debate surrounding the role of subcortical language mechanisms and be provided with new information on the comparative picture description abilities of individuals with known vascular and degenerative subcortical pathologies and healthy control participants. (c) 2005 Elsevier Inc. All rights reserved.

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West Nile Virus is becoming a widespread pathogen, infecting people on at least four continents with no effective treatment for these infections or many of their associated pathologies. A key enzyme that is essential for viral replication is the viral protease NS2B-NS3, which is highly conserved among all flaviviruses. Using a combination of molecular fitting of substrates to the active site of the crystal structure of NS3,site-directed enzyme and cofactor mutagenesis, and kinetic studies on proteolytic processing of panels of short peptide substrates, we have identified important enzyme-substrate interactions that define substrate specificity for NS3 protease. In addition to better understanding the involvement of S2, S3, and S4 enzyme residues in substrate binding, a residue within cofactor NS2B has been found to strongly influence the preference of flavivirus proteases for lysine or arginine at P2 in substrates. Optimization of tetrapeptide substrates for enhanced protease affinity and processing efficiency has also provided important clues for developing inhibitors of West Nile Virus infection.

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This paper examines a number of French middle-brow novels, usually called at the time romans de murs, from the period 1880-1910. It shows how, in these stories, doctors are shown to foretell the course of narrative through the diagnosis of certain pathologies, especially psychosexual ones. These pathologies are thus represented as implacable narrative programmes. In effect, most of these novels renounce the standard fictional resources of intrigue and suspense in favour of the relentless working out of their initial prognosis. The authority of medical discourse is therefore not just confirmed and disseminated: it is elaborated as fatality in the very terms of the novel. Copyright © SAGE Publications.

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Este estudo apresenta uma discussão a respeito de drogas e de alunos usuários de drogas na escola, explorando as Representações Sociais manifestadas por professores que atuam na Rede Estadual de São Paulo, no ensino Médio. O estudo resgata aspectos históricos e sociais que influenciaram representações sociais sobre drogas em diferentes contextos da sociedade, na perspectiva de buscar compreender a maneira como atualmente elas se apresentam. Discute aspectos conceituais da Teoria das Representações Sociais a partir de Moscovici, considerando contribuições de Jodelet, e outros autores. Os dados coletados por meio de questionários e entrevistas foram analisados com o auxílio de dois softwares, o ALCESTE para análise lexical e o EVOC para análise de associação de palavras ou expressões, em articulação com uma análise de conteúdo clássica sugerida por Maria Laura Puglisi Barbosa Franco. O resultado identificou que as representações sociais sobre drogas na escola e alunos usuários estão ancoradas no modo como a grande mídia trata o tema, de forma alarmista e sensacionalista, influenciando grande parte dos professores que associa drogas na escola à violência. Verificou-se ainda que objetivação do aluno usuário de drogas é simbolizada como doença e que o grupo pesquisado segue as representações sociais há muito tempo estruturadas na sociedade, tendo a normalidade como sinônimo de saúde e a drogadição como condição desviante, decorrente de patologias. Assim, espera-se estar contribuindo para a reflexão sobre o uso e abuso de drogas nas escolas, um tema indispensável e que precisa ser enfrentado para construir-se uma via que leve a uma Educação justa e democrática.(AU)