533 research outputs found
Using community development to build critical health literacy
Critical health literacy is a domain of health literacy that has been presented as existing at both individual and community level with a potential to contribute to improved health outcomes and reduced inequalities. However, it remains the least well explored and researched domain of health literacy and there are few examples of initiatives designed specifically to build critical health literacy. This study explores how community development processes can be used to develop the key attributes of critical health literacy
Nutrition and colony investment in Solenopsis invicta workers
Dissertação de Mestrado em Biologia Celular e Molecular, apresentada ao Departamento de Ciências da Vida Da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.A proteÃna Tau é responsável pela ligação e estabilização dos microtúbulos (MT) no citoesqueleto, sendo fundamental na função neuronal. A atividade desta proteÃna pode ser regulada por modificações pós-translacionais, como a fosforilação, que promovem a separação dos microtúbulos. A alteração na conformação da Tau provocada por uma deficiente regulação, como a hÃper-fosforilação, causa destabilização dos MT e agregação da mesma em filamentos helicoidais emparelhados e tranças neurofibrilares. Estas estruturas são uma das principais caracterÃsticas na doença de Alzheimer (AD), e o seu processo de formação pode representar um dos principais motivos que leva a morte celular nas Tauopatias, inclusivamente AD e outras patologias neurodegenerativas.
Nos últimos anos, recursos têm sido empregues na descoberta de novas estratégias que permitam diminuir a formação ou diminuam a quantidade de agregados da Tau dentro das células. Estudos recentes identificaram a indução da autofagia através da rapamicina como um dos potenciais alvos no aumento da remoção de agregados proteicos associados a doenças neurodegenerativas, melhorando também a esperança de vida em ratos e outros modelos.
Recentemente, o nosso laboratório desenvolveu um modelo celular baseado no trabalho de Guo e Lee (2011) que mimetiza a agregação intracelular da Tau depois de induzida a expressão de uma forma mutada desta proteÃna seguido do seeding com fibrilas K18:P301L pré-agregadas. Neste estudo, foi possÃvel demonstrar como a utilização destes modelos permite identificar novos compostos com atividade nas vias de redução da Tau. Curiosamente estas moléculas foram responsáveis pelo desenvolvimento de um fenótipo vesicular que identificámos como sendo lisossomas, derivados de um possÃvel estÃmulo na via endócitica. As alterações na morfologia sub-celular foram acompanhadas por modificações em marcadores de autofagia, sem aumento no fluxo autofágico. Estes dados sugerem que o aumento na degradação de proteÃnas e estruturas por autofagia poderão ter origem em efeitos colaterais de outras vias em detrimento do estÃmulo direto.
Para além disso, testamos uma série de moléculas com atividade reconhecida e validadas para induzir autofagia ou bloquear a degradação no lisossoma. Foi demonstrado que no nosso modelo, a ativação da autofagia não é responsável pela remoção de agregados. Por outro lado, provámos que os lisossomas são extremamente importantes da degradação de agregados da Tau.
Por fim, usámos o fator de transcrição EB (TFEB) para aumentar a biogénese de lisossomas e a autofagia. Células transfectadas com este fator apresentaram menos agregados de Tau e um aumento na viabilidade celular. Quando considerados em conjunto, estes resultados demonstram que a biogénese de lisossomas seguida por estÃmulos na autofagia podem ser mais importantes do que a ativação da autofagia por si só.
Concluindo, com este projeto foi não só possÃvel identificar os mecanismos dos compostos responsáveis pela degradação dos agregados de Tau, como também foi possÃvel validar o TFEB como um potencial novo alvo na descoberta de novos fármacos.Tau protein is responsible for binding and stabilizing microtubules (MT) in the cytoskeleton, thus supporting neuronal function. This protein activity can be regulated by post-translation modifications, such as phosphorylation, which promotes MT detachment. Tau misfolding provoked by abnormal regulation, like hyperphosphorilation, causes MT destabilization and Tau aggregation into paired helical filaments (PHF) and neurofibrillary tangles (NFTs). These structures are one of the main hallmarks in Alzheimer’s disease (AD), and its formation process may represent the principal motive for cell death in many Tauopathies, including AD and other neurodegenerative disorders.
Over the last years, great efforts have been placed to find new strategies to either diminish the build-up or decrease the amount of aggregated Tau inside cells. Recent studies have identified induction of autophagy through rapamycin as a potential target in increasing the clearance of aggregated proteins associated with neurodegenerative diseases, as well as ameliorating life expectancy in rats and other animal models.
Recently, our lab developed a cellular model based on the work by Guo and Lee (2011) that mimics the intracellular aggregation of Tau after overexpression of a mutated form of this protein and seeding with pre-aggregated K18:P301L fibrils. In this study, we have taken advantage of the developed model to discover new compounds active in Tau reduction pathways. Interestingly these molecules were responsible for the development of a vesicular phenotype that we identified as lysosomes due to a possible stimulation of the endocytic pathway. The change of the sub cellular morphology was followed by changes in autophagy markers, with no increase in the autophagic flux. This suggests an increment in the degradation of proteins and structures by autophagy as a collateral result from the activation of other pathways rather than a direct stimulus.
Furthermore, we have tested a series of molecules with known and validated activity to induce autophagy or disable degradation via the lysosome. We showed that at least in our model, autophagy activation is not responsible for the clearance of aggregates. On the other hand, we have proven that lysosomes play a critical role in Tau aggregates degradation.
Finally, we have used the transcription factor EB (TFEB) to intensify lysosomal biogenesis and autophagy. Cells transfected with this transcription factor had less Tau aggregates and cell viability was slightly increased. When considered together, these results show that lysosomal biogenesis followed by autophagy stimulation may be more important for clearance of Tau aggregates than autophagy by itself.
In conclusion, we have not only determined the mechanisms targeted by the compounds responsible for the degradation of Tau aggregates, but also validated TFEB as a potential new target for drug discovery
C. trachomatis pgp3 antibody prevalence in young women in England, 1993-2010
Seroepidemiology of chlamydia can offer study opportunities and insights into cumulative risk of exposure that may contribute to monitoring the frequency of, and control of, genital chlamydia-the most commonly diagnosed STI in England. We undertook retrospective anonymous population-based cross-sectional surveys using an indirect IgG ELISA for chlamydia Pgp3 antibody. Sera from 4,732 women aged 17-24 years were tested. Samples were taken at 3-yearly intervals between 1993 and 2002, a period during which other data suggest chlamydia transmission may have been increasing, and from each year between 2007 and 2010. Seroprevalence increased in 17-24 year olds over time between 1993 and 2002. Between 2007 and 2010, age-standardised seroprevalence among 17-24 year olds decreased from 20% (95% CI: 17-23) to 15% (95%CI 12-17) (p = 0.0001). The biggest drop was among 20 to 21 year olds, where seroprevalence decreased from 21% in 2007 to 9% in 2010 (p = 0.002). These seroprevalence data reflect some known features of the epidemiology of chlamydia infection, and show that exposure to antibody-inducing chlamydia infection has declined in recent years. This decline was concurrent with increasing rates of screening for asymptomatic chlamydia. Serology should be explored further as a tool for evaluation of chlamydia control, including chlamydia screening programmes
Evaluation of the automated MicroFlow® and Metafer™ platforms for high-throughput micronucleus scoring and dose response analysis in human lymphoblastoid TK6 cells
Amine-modified polyionic liquid supports enhance the efficacy of PdNPs for the catalytic hydrogenation of CO<sub>2</sub> to formate
Amino-Modified Polymer Immobilized Ionic Liquid Stabilized Ruthenium Nanoparticles: Efficient and Selective Catalysts for the Partial and Complete Reduction of Quinolines
RuNPs stabilised by amino-decorated imidazolium-based polymer immobilized ionic liquids catalyse the dimethylamine borane mediated reduction of quinolines to 1,2-dihydroquinoline (DHQ) and 1,2,3,4-tetrahydroquinoline (THQ). Partial reduction of 3-substituted quinolines to the corresponding 1,2-dihydroquinoline was achieved with 100 % selectivity in toluene under mild conditions. This is the first report of the selective partial reduction of 3-substituted quinolines to the corresponding 1,2-dihydroquinolines with a heterogeneous nanoparticle-based catalyst. A wide range of substituted quinolines have also been reduced to the corresponding 1,2,3,4-tetrahydroquinoline with high selectivity and good yields by adjusting the reaction time. The 1,2-dihydroquinolines readily release dihydrogen in toluene at 60 °C in the absence of catalyst with no evidence for disproportionation and as such are potential organo-hydride reagents. The initial TOF of 610 mol quinoline converted mol Ru−1 h−1 for the reduction of quinoline is among the highest to be reported for a metal nanoparticle-based catalyst and the conversion of 96 % obtained after 4 h at 65 °C is significantly higher than its platinum nanoparticle counterpart PtNP@NH2-PEGPIILS as well as 5 wt/% Ru/C, which only reached 9 % and 11 % conversion, respectively, at the same time. Hot filtration experiments showed that the active species was heterogeneous
Tau Reduction Does Not Prevent Motor Deficits in Two Mouse Models of Parkinson's Disease
Many neurodegenerative diseases are increasing in prevalence and cannot be prevented or cured. If they shared common pathogenic mechanisms, treatments targeting such mechanisms might be of benefit in multiple conditions. The tau protein has been implicated in the pathogenesis of diverse neurodegenerative disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD). Tau reduction prevents cognitive deficits, behavioral abnormalities and other pathological changes in multiple AD mouse models. Here we examined whether tau reduction also prevents motor deficits and pathological alterations in two mouse models of PD, generated by unilateral striatal injection of 6-hydroxydopamine (6-OHDA) or transgene-mediated neuronal expression of human wildtype α-synuclein. Both models were evaluated on Tau+/+, Tau+/– and Tau–/– backgrounds in a variety of motor tests. Tau reduction did not prevent motor deficits caused by 6-OHDA and slightly worsened one of them. Tau reduction also did not prevent 6-OHDA-induced loss of dopaminergic terminals in the striatum. Similarly, tau reduction did not prevent motor deficits in α-synuclein transgenic mice. Our results suggest that tau has distinct roles in the pathogeneses of AD and PD and that tau reduction may not be of benefit in the latter condition
The Seroprevalence and Seroincidence of Enterovirus71 Infection in Infants and Children in Ho Chi Minh City, Viet Nam
Enterovirus 71 (EV71)-associated hand, foot and mouth disease has emerged as a serious public health problem in South East Asia over the last decade. To better understand the prevalence of EV71 infection, we determined EV71 seroprevalence and seroincidence amongst healthy infants and children in Ho Chi Minh City, Viet Nam. In a cohort of 200 newborns, 55% of cord blood samples contained EV71 neutralizing antibodies and these decayed to undetectable levels by 6 months of age in 98% of infants. The EV71 neutralizing antibody seroconversion rate was 5.6% in the first year and 14% in the second year of life. In children 5–15 yrs of age, seroprevalence of EV71 neutralizing antibodies was 84% and in cord blood it was 55%. Taken together, these data suggest EV71 force of infection is high and highlights the need for more research into its epidemiology and pathogenesis in high disease burden countries
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