Mostrando recursos 1 - 12 de 12

  1. Implicit sequence learning is preserved in dyslexic children

    Inácio, Filomena; Faísca, Luís; Forkstam, Christian; Araújo, Susana; Bramão, Inês; Reis, Alexandra; Petersson, Karl Magnus
    This study investigates the implicit sequence learning abilities of dyslexic children using an artificial grammar learning task with an extended exposure period. Twenty children with developmental dyslexia participated in the study and were matched with two control groups-one matched for age and other for reading skills. During 3 days, all participants performed an acquisition task, where they were exposed to colored geometrical forms sequences with an underlying grammatical structure. On the last day, after the acquisition task, participants were tested in a grammaticality classification task. Implicit sequence learning was present in dyslexic children, as well as in both control groups, and...

  2. Intracellular replication of Streptococcus pneumoniae inside splenic macrophages serves as a reservoir for septicaemia

    Ercoli, Giuseppe; Fernandes, Vitor E.; Chung, Wen Y.; Wanford, Joseph J.; Thomson, Sarah; Bayliss, Christopher D.; Straatman, Kornelis; Crocker, Paul R.; Dennison, Ashley; Martinez-Pomares, Luisa; Andrew, Peter W.; Moxon, E. Richard; Oggioni, Marco R.
    Bacterial septicaemia is a major cause of mortality, but its pathogenesis remains poorly understood. In experimental pneumococcal murine intravenous infection, an initial reduction of bacteria in the blood is followed hours later by a fatal septicaemia. These events represent a population bottleneck driven by efficient clearance of pneumococci by splenic macrophages and neutrophils, but as we show in this study, accompanied by occasional intracellular replication of bacteria that are taken up by a subset of CD169+ splenic macrophages. In this model, proliferation of these sequestered bacteria provides a reservoir for dissemination of pneumococci into the bloodstream, as demonstrated by its...

  3. The tumorigenic roles of the cellular REDOX regulatory systems

    Castaldo, Stéphanie Anais; Freitas, Joana Raquel; Conchinha, Nadine Vasconcelos; Madureira, Patrícia A.
    The cellular REDOX regulatory systems play a central role in maintaining REDOX homeostasis that is crucial for cell integrity, survival, and proliferation. To date, a substantial amount of data has demonstrated that cancer cells typically undergo increasing oxidative stress as the tumor develops, upregulating these important antioxidant systems in order to survive, proliferate, and metastasize under these extreme oxidative stress conditions. Since a large number of chemotherapeutic agents currently used in the clinic rely on the induction of ROS overload or change of ROS quality to kill the tumor, the cancer cell REDOX adaptation represents a significant obstacle to conventional...

  4. Too little or too much? Parafoveal preview benefits and parafoveal load costs in dyslexic adults

    Silva, Susana; Faísca, Luís; Araújo, Susana; Casaca, Luis; Carvalho, Loide; Petersson, Karl Magnus; Reis, Alexandra
    Two different forms of parafoveal dysfunction have been hypothesized as core deficits of dyslexic individuals: reduced parafoveal preview benefits ("too little parafovea") and increased costs of parafoveal load ("too much parafovea"). We tested both hypotheses in a single eye-tracking experiment using a modified serial rapid automatized naming (RAN) task. Comparisons between dyslexic and non-dyslexic adults showed reduced parafoveal preview benefits in dyslexics, without increased costs of parafoveal load. Reduced parafoveal preview benefits were observed in a naming task, but not in a silent letter-finding task, indicating that the parafoveal dysfunction may be consequent to the overload with extracting phonological information...

  5. Visual naming deficits in dyslexia: An ERP investigation of different processing domains

    Araújo, Susana; Faísca, Luís; Reis, Alexandra; Frederico Marques, J.; Petersson, Karl Magnus
    Naming speed deficits are well documented in developmental dyslexia, expressed by slower naming times and more errors in response to familiar items. Here we used event-related potentials (ERPs) to examine at what processing level the deficits in dyslexia emerge during a discrete-naming task. Dyslexic and skilled adult control readers performed a primed object-naming task, in which the relationship between the prime and the target was manipulated along perceptual, semantic and phonological dimensions. A 3 x 2 design that crossed Relationship Type (Visual, Phonemic Onset, and Semantic) with Relatedness (Related and Unrelated) was used. An attenuated N/P190 - indexing early visual...

  6. Mechanisms of human telomerase reverse transcriptase (hTERT) regulation: clinical impacts in cancer

    Leão, Ricardo; Apolónio, Joana D.; Lee, Donghyun; Figueiredo, Arnaldo; Tabori, Uri; Castelo-Branco, Pedro
    Background Limitless self-renewal is one of the hallmarks of cancer and is attained by telomere maintenance, essentially through telomerase (hTERT) activation. Transcriptional regulation of hTERT is believed to play a major role in telomerase activation in human cancers. Main body The dominant interest in telomerase results from its role in cancer. The role of telomeres and telomere maintenance mechanisms is well established as a major driving force in generating chromosomal and genomic instability. Cancer cells have acquired the ability to overcome their fate of senescence via telomere length maintenance mechanisms, mainly by telomerase activation. hTERT expression is up-regulated...

  7. Ear wound regeneration in the African spiny mouse Acomys cahirinus

    Santos, Dino Matias; Rita, Ana Martins; Casanellas, Ignasi; Ova, Adelia Brito; Araújo, Inês; Power, Deborah; Tiscornia, Gustavo
    While regeneration occurs in a number of taxonomic groups across the Metazoa, there are very few reports of regeneration in mammals, which generally respond to wounding with fibrotic scarring rather than regeneration. A recent report described skin shedding, skin regeneration and extensive ear punch closure in two rodent species, Acomys kempi and Acomys percivali. We examined these striking results by testing the capacity for regeneration of a third species, Acomys cahirinus, and found a remarkable capacity to repair full thickness circular punches in the ear pinna. Four-millimeter-diameter wounds closed completely in 2 months in 100% of ear punches tested. Histology...

  8. Synthesis and characterization of Locust Bean Gum derivatives and their application in the production of nanoparticles

    Braz, L.; Grenha, Ana; Corvo, Marta C.; Lourenço, J. P.; Ferreira, Domingos; Sarmento, Bruno; Costa, Ana M. Rosa da
    The development of LBG-based nanoparticles intending an application in oral immunization is presented. Nanoparticle production occurred by mild polyelectrolyte complexation, requiring the chemical modification of LBG. Three LBG derivatives were synthesized, namely a positively charged ammonium derivative (LBGA) and negatively charged sulfate (LBGS) and carboxylate (LBGC) derivatives. These were characterized by Fourier-transform infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, gel permeation chromatography, and x-ray diffraction. As a pharmaceutical application was aimed, a toxicological analysis of the derivatives was performed by both MTT test and LDH release assay. Several nanoparticle formulations were produced using LBGA or chitosan (CS) as positively...

  9. Motor dysfunctions and neuropathology in mouse models of spinocerebellar ataxia type 2: A comprehensive review

    Alves-Cruzeiro, João M. da Conceição; Mendonça, Liliana; Almeida, Luís Pereira de; Nóbrega, Clévio
    Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant ataxia caused by an expansion of CAG repeats in the exon 1 of the gene ATXN2, conferring a gain of toxic function that triggers the appearance of the disease phenotype. SCA2 is characterized by several symptoms including progressive gait ataxia and dysarthria, slow saccadic eye movements, sleep disturbances, cognitive impairments, and psychological dysfunctions such as insomnia and depression, among others. The available treatments rely on palliative care, which mitigate some of the major symptoms but ultimately fail to block the disease progression. This persistent lack of effective therapies led to the...

  10. Dimensões da qualidade de vida e apoio social dos pacientes hospitalizados nas unidades de assistência à saúde do Algarve

    Duarte, António; Joaquim, Natércia; Nunes, Cristina
    This study assessed the relations between quality of life and social support network of patients in continuing care units in Algarve, using WHOQOL-BREF and ASSIS. Participants were 92 users of ages between 34-101 years: very elderly (40.2%), female (58.7%), widows (40.2%), upper-middle class (46.8%), cohabiting with spouse (43.2%), and partly dependent (72.5%). Emotional, tangible and informational support networks were mainly composed by family. We found significant associations between informative social support and physical domains, social relations and environment of quality of life (p< 0.05). The results suggest middle levels in self-perception and satisfaction with health, and lower levels in physical...

  11. The role of hypoxia in glioblastoma invasion

    Monteiro, Ana; Hill, Richard; Pilkington, Geoffrey; Madureira, Patrícia
    Glioblastoma multiforme (GBM), a grade IV astrocytoma, is the most common and deadly type of primary malignant brain tumor, with a patient's median survival rate ranging from 15 to 17 months. The current treatment for GBM involves tumor resection surgery based on MRI image analysis, followed by radiotherapy and treatment with temozolomide. However, the gradual development of tumor resistance to temozolomide is frequent in GBM patients leading to subsequent tumor regrowth/relapse. For this reason, the development of more effective therapeutic approaches for GBM is of critical importance. Low tumor oxygenation, also known as hypoxia, constitutes a major concern for GBM...

  12. rdml: A Mathematica package for parsing and importing Real-Time qPCR data

    Magno, Ramiro; Duarte, Isabel; Andrade, Raquel P.; Palmeirim, Isabel
    Objective The purpose and objective of the research presented is to provide a package for easy importing of Real-Time PCR data markup language (RDML) data to Mathematica. Results Real-Time qPCR is the most widely used experimental method for the accurate quantification of gene expression. To enable the straightforward archiving and sharing of qPCR data and its associated experimental information, an XML-based data standard was developed—the Real-Time PCR data markup language (RDML)—devised by the RDML consortium. Here, we present rdml, a package to parse and import RDML data into Mathematica, allowing the quick loading and extraction of relevant data,...

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