40 research outputs found

    The Role of Aspirin in Preeclampsia Prevention: State of the Art

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    Introdução: O papel do ĂĄcido acetilsalicĂ­lico (AAS ou aspirina) na prevenção das complicaçÔes associadas Ă  prĂ©-eclĂąmpsia tem sido objeto de estudos e de controvĂ©rsias ao longo de 30 anos. Os primeiros trabalhos de investigação acerca do papel da placenta na gĂ©nese da prĂ©-eclĂąmpsia surgiram em finais dos anos 70 e assinalavam um aumento da atividade plaquetĂĄria e alteração da sĂ­ntese das prostaglandinas, como consequĂȘncia da deficiente adaptação da placenta. Ao longo dos Ășltimos 20 anos do sĂ©culo XX, sucederam-se estudos de investigação acerca do papel profilĂĄtico da aspirina na redução do risco de prĂ©-eclĂąmpsia. Material e MĂ©todos: Para analisar os trabalhos publicados sobre o uso da aspirina na prevenção da prĂ©-eclĂąmpsia, bem como sobre a dose mais adequada e momento de administração, foram consultados apenas estudos prospetivos, revisĂ”es sistemĂĄticas e meta-anĂĄlises atravĂ©s das seguintes fontes pesquisa (PubMed, Cochrane, Embase). Os artigos citados foram considerados os mais relevantes. Os trabalhos foram divididos em dois grupos: no primeiro foram incluĂ­dos os trabalhos em que a aspirina era administrada atĂ© Ă s 16 semanas e o segundo, com inĂ­cio de administração por um perĂ­odo mais alargado. Resultados e DiscussĂŁo: No primeiro grupo, com menor nĂșmero de casos, mas com inĂ­cio mais precoce de administração do fĂĄrmaco, atĂ© Ă s 16 semanas, concluiu-se que a aspirina poderia ter um papel positivo na redução de risco de gravidade da prĂ©-eclĂąmpsia; o segundo grupo, com maior nĂșmero de casos nos estudos, mas com condiçÔes menos restritas de entrada e de tempo de inĂ­cio do fĂĄrmaco, teve resultados mais controversos. As meta-anĂĄlises destes estudos concluĂ­ram que os resultados favorĂĄveis estavam associados Ă s condiçÔes de e momento da administração. ConclusĂŁo: NĂŁo existindo ainda alternativas ou fĂĄrmacos que lhe possam ser associados, a aspirina em baixas doses (80 a 150 mg/dia) ao deitar, iniciada no 1Âș trimestre e atĂ© Ă s 16 semanas mantĂ©m-se um fĂĄrmaco seguro, que tem contribuĂ­do para redução do risco de prĂ©-eclĂąmpsia precoce, com as consequĂȘncias que lhe estĂŁo associadas

    Associations between nutrient intake and gastrointestinal symptoms in autism spectrum disorder

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    Many children and adolescents with autism spectrum disorder (ASD) have significant gastrointestinal (GI) symptoms, but the etiology is not well understood. Studies have shown conflicting evidence on whether there are nutritional deficiencies in the various diets of individuals with ASD. However, little is known about the relationship between dietary intake and GI symptomatology in ASD. The goal of the present study was to assess for potential relationships between GI symptoms and nutrient intake from diet in the same sample of individuals from the previous study, and to determine whether dietary differences might have contributed to our previously observed findings of a relationship between stress responses and GI functioning in ASD

    The SET and transposase domain protein Metnase enhances chromosome decatenation: regulation by automethylation

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    Metnase is a human SET and transposase domain protein that methylates histone H3 and promotes DNA double-strand break repair. We now show that Metnase physically interacts and co-localizes with Topoisomerase IIα (Topo IIα), the key chromosome decatenating enzyme. Metnase promotes progression through decatenation and increases resistance to the Topo IIα inhibitors ICRF-193 and VP-16. Purified Metnase greatly enhanced Topo IIα decatenation of kinetoplast DNA to relaxed circular forms. Nuclear extracts containing Metnase decatenated kDNA more rapidly than those without Metnase, and neutralizing anti-sera against Metnase reversed that enhancement of decatenation. Metnase automethylates at K485, and the presence of a methyl donor blocked the enhancement of Topo IIα decatenation by Metnase, implying an internal regulatory inhibition. Thus, Metnase enhances Topo IIα decatenation, and this activity is repressed by automethylation. These results suggest that cancer cells could subvert Metnase to mediate clinically relevant resistance to Topo IIα inhibitors

    Representational Switching by Dynamical Reorganization of Attractor Structure in a Network Model of the Prefrontal Cortex

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    The prefrontal cortex (PFC) plays a crucial role in flexible cognitive behavior by representing task relevant information with its working memory. The working memory with sustained neural activity is described as a neural dynamical system composed of multiple attractors, each attractor of which corresponds to an active state of a cell assembly, representing a fragment of information. Recent studies have revealed that the PFC not only represents multiple sets of information but also switches multiple representations and transforms a set of information to another set depending on a given task context. This representational switching between different sets of information is possibly generated endogenously by flexible network dynamics but details of underlying mechanisms are unclear. Here we propose a dynamically reorganizable attractor network model based on certain internal changes in synaptic connectivity, or short-term plasticity. We construct a network model based on a spiking neuron model with dynamical synapses, which can qualitatively reproduce experimentally demonstrated representational switching in the PFC when a monkey was performing a goal-oriented action-planning task. The model holds multiple sets of information that are required for action planning before and after representational switching by reconfiguration of functional cell assemblies. Furthermore, we analyzed population dynamics of this model with a mean field model and show that the changes in cell assemblies' configuration correspond to those in attractor structure that can be viewed as a bifurcation process of the dynamical system. This dynamical reorganization of a neural network could be a key to uncovering the mechanism of flexible information processing in the PFC

    Habitat specificity of a threatened and endemic cliff-dwelling halophyte

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    Research ArticleCoastal areas and other saline environments are major contributors to regional and global biodiversity patterns. In these environments, rapidly changing gradients require highly specialized plants like halophytes. In European coastal cliff-tops, rocky and sandy seashores, and saltmarshes, typical halophytes from the genus Limonium are commonly found. Among them, the aneuploid tetraploid (2n ÂŒ 4x ÂŒ 35, 36, 37) Limonium multiflorum, endemic to the west coast of Portugal, is an interesting case study for investigating the ecology and conservation of a halophyte agamospermic species. Although it is listed in the IUCN red list of threatened species, information on its population size or rarity, as well as its ecology, in some respects is still unknown. Field surveys in the largest known population were performed (Raso cape, Portugal) in order to determine habitat requirements and conservation status. A total of 88 quadrats were monitored, 43 of which contained at least one L. multiflorum individual. For each sampled quadrat, four abiotic and four biotic variables as well as two spatially derived variables were recorded. Principal component analysis and cluster analysis showed narrow habitat specificity for this species which appeared to be intolerant to competition with invasive alien plants. We conclude that in situ conservation in a local ‘hotspot’ of this rare and vulnerable species emerges as a priority in order to ensure that biodiversity is not los

    Copper indium diselenide: crystallography and radiation-induced dislocation loops

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    Copper indium diselenide (CIS) is a prime candidate as the absorber layer in solar cells for use in extraterrestrial environments due to its good photovoltaic efficiency and ability to resist radiation damage. While CIS-based devices have been tested extensively in the laboratory using electron and proton irradiation, there is still little understanding of the underlying mechanisms which give rise to its radiation hardness. To gain better insight into the response of CIS to displacing radiation, transmission electron microscope samples have been irradiated in situ with 400 keV Xe ions at the Intermediate Voltage Electron Microscope facility at Argonne National Laboratory, USA. At room temperature, dislocation loops were observed to form and grow with increasing fluence. These loops have been investigated using g  ·  b techniques and inside/outside contrast analysis. They have been found to reside on {112} planes and to be interstitial in nature. The Burgers vector were calculated as b  = 1/6 221. The compositional content of these interstitial loops was found to be indistinguishable from the surrounding matrix within the sensitivity of the techniques used. To facilitate this work, experimental electron-diffraction zone-axis pattern maps were produced and these are also presented, along with analysis of the [100] zone-axis pattern
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