588 research outputs found

    Reduced Expression of the Vesicular Acetylcholine Transporter and Neurotransmitter Content Affects Synaptic Vesicle Distribution and Shape in Mouse Neuromuscular Junction

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    In vertebrates, nerve muscle communication is mediated by the release of the neurotransmitter acetylcholine packed inside synaptic vesicles by a specific vesicular acetylcholine transporter (VAChT). Here we used a mouse model (VAChT KDHOM) with 70% reduction in the expression of VAChT to investigate the morphological and functional consequences of a decreased acetylcholine uptake and release in neuromuscular synapses. Upon hypertonic stimulation, VAChT KDHOM mice presented a reduction in the amplitude and frequency of miniature endplate potentials, FM 1-43 staining intensity, total number of synaptic vesicles and altered distribution of vesicles within the synaptic terminal. In contrast, under electrical stimulation or no stimulation, VAChT KDHOM neuromuscular junctions did not differ from WT on total number of vesicles but showed altered distribution. Additionally, motor nerve terminals in VAChT KDHOM exhibited small and flattened synaptic vesicles similar to that observed in WT mice treated with vesamicol that blocks acetylcholine uptake. Based on these results, we propose that decreased VAChT levels affect synaptic vesicle biogenesis and distribution whereas a lower ACh content affects vesicles shape

    The SWR1 Histone Replacement Complex Causes Genetic Instability and Genome-Wide Transcription Misregulation in the Absence of H2A.Z

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    The SWR1 complex replaces the canonical histone H2A with the variant H2A.Z (Htz1 in yeast) at specific chromatin regions. This dynamic alteration in nucleosome structure provides a molecular mechanism to regulate transcription, gene silencing, chromosome segregation and DNA repair. Here we show that genetic instability, sensitivity to drugs impairing different cellular processes and genome-wide transcriptional misregulation in htz1Δ can be partially or totally suppressed if SWR1 is not formed (swr1Δ), if it forms but cannot bind to chromatin (swc2Δ) or if it binds to chromatin but lacks histone replacement activity (swc5Δ and the ATPase-dead swr1-K727G). These results suggest that in htz1Δ the nucleosome remodelling activity of SWR1 affects chromatin integrity because of an attempt to replace H2A with Htz1 in the absence of the latter. This would impair transcription and, either directly or indirectly, other cellular processes. Specifically, we show that in htz1Δ, the SWR1 complex causes an accumulation of recombinogenic DNA damage by a mechanism dependent on phosphorylation of H2A at Ser129, a modification that occurs in response to DNA damage, suggesting that the SWR1 complex impairs the repair of spontaneous DNA damage in htz1Δ. In addition, SWR1 causes DSBs sensitivity in htz1Δ; consistently, in the absence of Htz1 the SWR1 complex bound near an endonuclease HO-induced DSB at the mating-type (MAT) locus impairs DSB-induced checkpoint activation. Our results support a stepwise mechanism for the replacement of H2A with Htz1 and demonstrate that a tight control of this mechanism is essential to regulate chromatin dynamics but also to prevent the deleterious consequences of an incomplete nucleosome remodelling

    Dynamics of early establishment of SARS-CoV-2 VOC Omicron lineages in Minas Gerais, Brazil

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    Brazil is one of the nations most affected by Coronavirus disease 2019 (COVID-19). The introduction and establishment of new virus variants can be related to an increase in cases and fatalities. The emergence of Omicron, the most modified SARS-CoV-2 variant, caused alarm for the public health of Brazil. In this study, we examined the effects of the Omicron introduction in Minas Gerais (MG), the second-most populous state of Brazil. A total of 430 Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) samples from November 2021 to June 2022 from Belo Horizonte (BH) city were sequenced. These newly sequenced genomes comprise 72% of all previously available SARS-CoV-2 genomes for the city. Evolutionary analysis of novel viral genomes reveals that a great diversity of Omicron sublineages have circulated in BH, a pattern in-keeping with observations across Brazil more generally. Bayesian phylogeographic reconstructions indicate that this diversity is a product of a large number of international and national importations. As observed previously, SĂŁo Paulo state is shown as a significant hub for viral spread throughout the country, contributing to around 70% of all viral Omicron introductions detected in MG

    Prospective study of patients with persistent symptoms of dengue in Brazil

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    Dengue is an arboviral infection clinically recognized as an acute and self-limited disease. Persistence of dengue symptoms is known, but it has been little studied. The aim of this study was to characterize persistent symptoms in 113 patients with dengue followed up clinically and by laboratory testing at a tertiary hospital. Symptoms that persisted for more than 14 days were observed in 61 (54.0%) patients, and six (6.2%) of them had symptoms for 6 months or more. The persistent symptoms identified were myalgia, weakness, hair loss, memory loss, reduced resistance to physical effort, headache, reasoning problems, arthralgia, sleepiness- and emotional lability. The progression to persistent symptoms was significantly associated with hospitalization, older age, more severe disease, the presence of bleeding and comorbidities upon univariate analysis. Upon multivariate analysis, the presence of persistent symptoms continued to be significantly associated only with increased age and dengue with warning signs. The platelet count during the acute phase of the disease was significantly lower in the group with persistent symptoms. In conclusion, the frequency of progression to persistent symptoms in dengue is relevant in patients seen at a tertiary hospital and the persistence of symptoms is more common in patients with dengue with warning signs

    Habitat and Scale Shape the Demographic Fate of the Keystone Sea Urchin Paracentrotus lividus in Mediterranean Macrophyte Communities

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    Demographic processes exert different degrees of control as individuals grow, and in species that span several habitats and spatial scales, this can influence our ability to predict their population at a particular life-history stage given the previous life stage. In particular, when keystone species are involved, this relative coupling between demographic stages can have significant implications for the functioning of ecosystems. We examined benthic and pelagic abundances of the sea urchin Paracentrotus lividus in order to: 1) understand the main life-history bottlenecks by observing the degree of coupling between demographic stages; and 2) explore the processes driving these linkages. P. lividus is the dominant invertebrate herbivore in the Mediterranean Sea, and has been repeatedly observed to overgraze shallow beds of the seagrass Posidonia oceanica and rocky macroalgal communities. We used a hierarchical sampling design at different spatial scales (100 s, 10 s and <1 km) and habitats (seagrass and rocky macroalgae) to describe the spatial patterns in the abundance of different demographic stages (larvae, settlers, recruits and adults). Our results indicate that large-scale factors (potentially currents, nutrients, temperature, etc.) determine larval availability and settlement in the pelagic stages of urchin life history. In rocky macroalgal habitats, benthic processes (like predation) acting at large or medium scales drive adult abundances. In contrast, adult numbers in seagrass meadows are most likely influenced by factors like local migration (from adjoining rocky habitats) functioning at much smaller scales. The complexity of spatial and habitat-dependent processes shaping urchin populations demands a multiplicity of approaches when addressing habitat conservation actions, yet such actions are currently mostly aimed at managing predation processes and fish numbers. We argue that a more holistic ecosystem management also needs to incorporate the landscape and habitat-quality level processes (eutrophication, fragmentation, etc.) that together regulate the populations of this keystone herbivore

    Teste de Morisky-Green e Brief Medication Questionnaire para avaliar adesĂŁo a medicamentos

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    OBJETIVO: Analisar a confiabilidade e o desempenho da versão em português de instrumentos de avaliação da adesão ao tratamento anti-hipertensivo. MÉTODOS: Pacientes hipertensos atendidos de janeiro a setembro de 2010 em uma unidade de atenção primária em Porto Alegre, RS, foram selecionados aleatoriamente (n = 206). Na avaliação da adesão foram utilizadas versões em português do Teste de Morisky-Green (TMG) e do Brief Medication Questionnaire (BMQ). Foram analisados consistência interna, estabilidade temporal e desempenho com relação a três padrões-ouro: controle inadequado da pressão arterial (&gt; 140/90 mmHg); taxa insuficiente de retirada de medicação na farmácia da Unidade Básica de Saúde (< 80%); e a combinação de ambos. RESULTADOS: Dos pacientes avaliados, 97 utilizavam medicamentos dispensados somente pela farmácia da Unidade Básica de Saúde. Os testes apresentaram boa consistência interna: BMQ &#945; de Cronbach de 0,66 (IC95% 0,60;0,73) e o TMG 0,73 (IC95% 0,67;0,79). O desempenho do BMQ no domínio regime apresentou sensibilidade de 77%, especificidade de 58% e área sob a curva ROC de 0,70 (IC95% 0,55;0,86), e o TMG sensibilidade de 61%, especificidade de 36% e área sob a curva ROC de 0,46 (IC95% 0,30;0,62). A correlação entre o BMQ e o TMG foi de r = 0,28, p &gt; 0,001. A baixa adesão ao BMQ está associada a maiores níveis tensionais quando comparada com pacientes aderentes (148,4 [dp 20,1] vs 128,8 [dp 17,8], p < 0,001), mas não para o TMG. CONCLUSÕES: O BMQ apresentou melhor desempenho que o TMG, com maiores sensibilidade e especificidade. A avaliação da adesão pode auxiliar o clinico na discriminação entre uso inadequado da medicação e esquema terapêutico insuficiente.OBJETIVO: Analizar la confiabilidad y el desempeño de la versión en portugués de instrumentos de evaluación de la adherencia al tratamiento antihipertensivo. MÉTODOS: Pacientes hipertensos atendidos de enero a septiembre de 2010 en una unidad de atención primaria en Porto Alegre, Sur de Brasil, fueron seleccionados aleatoriamente (n=206). En la evaluación de la adherencia fueron utilizadas versiones en portugués de la Prueba de Morisky-Green (TMG) y del Brief Medication Questionnarie (BMQ). Se analizaron consistencia interna, estabilidad temporal y desempeño con relación a tres patrones-oro: control inadecuado de la presión arterial (&gt; 140/90 mmHg); tasa insuficiente de retirada de medicación en la farmacia de la Unidad Básica de Salud (< 80%) y la combinación de ambos. RESULTADOS: De los pacientes evaluados, 97 utilizaban medicamentos dispensados solamente por la farmacia de la Unidad Básica de Salud. Las pruebas presentaron buena consistencia interna: BMQ &#945; de Cronbach de 0,66 (IC95% 0,60;0,73) y el TMG 0,73 (IC95% 0,67;0,79). El desempeño del BMQ en el dominio régimen presentó sensibilidad de 77%, especificidad de 58%, y área bajo la curva ROC de 0,70 (IC95% 0,55;0,86) y el TMG sensibilidad de 61%, especificidad de 36% y área bajo la curva ROC de 0,46 (IC95% 0,30;0,62). La correlación entre el BMQ y el TMG fue de r=0,28, p&gt;0,001. La baja adherencia al BMQ está asociada a mayores niveles tensionales al compararlo con pacientes adherentes 148,4 [de 0,1] vs 128,8 [de 17,8], pOBJECTIVE: To analyze the reliability and performance of the Portuguese version of questionnaires used to evaluate adherence to hypertensive treatment. METHODS: Hypertensive patients attending a primary healthcare unit in Porto Alegre, Southern Brazil, from January to September 2010, were randomly selected (n = 206). To evaluate adherence, Portuguese versions of the Morisky-Green test (MGT) and the Brief Medication Questionnaire (BMQ) were used. The analysis considered internal consistency, temporal stability and performance compared to three gold standards, which are: inadequate control of blood pressure (BP &gt; 140/90 mmHg); insufficient rate of medication acquisition at the institution's pharmacy

    Pleosporales

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    One hundred and five generic types of Pleosporales are described and illustrated. A brief introduction and detailed history with short notes on morphology, molecular phylogeny as well as a general conclusion of each genus are provided. For those genera where the type or a representative specimen is unavailable, a brief note is given. Altogether 174 genera of Pleosporales are treated. Phaeotrichaceae as well as Kriegeriella, Zeuctomorpha and Muroia are excluded from Pleosporales. Based on the multigene phylogenetic analysis, the suborder Massarineae is emended to accommodate five families, viz. Lentitheciaceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae and Trematosphaeriaceae

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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