2,736 research outputs found

    Reconstitution of hepatitis B virus (HBV)-specific T cell responses with treatment of human immunodeficiency virus/HBV coinfection

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    Liver-related mortality is an increasing problem in human immunodeficiency virus (HIV)/hepatitis B virus (HBV)-coinfected patients receiving highly active antiretroviral therapy (HAART). In HIV-negative patients, HBV chronicity is associated with a reduction in specific T cell responses that can be partially restored by treatment with lamivudine. We studied 5 HIV/HBV-coinfected patients treated with HAART, either with or without addition of a drug with specific anti-HBV activity. Our data show that reconstitution of some HBV-specific T cell responses can also occur in HIV-positive patients after a reduction in HBV load. This potential to recover T cell responses, which has been thought to be critical for HBV control, provides support for the addition of anti-HBV therapy in the treatment of HIV/HBV-coinfected patients

    Effects of microalgal exudates and intact cells on subtropical marine zooplankton

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    Harmful algal blooms (HABs) affect coastal waters worldwide and very often lead to the disruption of seafood harvesting and commercial activities, because of potential hazards to human health associated with the consumption of contaminated mussels, crustaceans and fish. HAB events are frequently caused by outbreaks of toxin-producing dinoflagellates, which are subject to top-down control by zooplankton. The aim of this study was to analyze the effects of dinoflagellate exudates and intact cells on the survivorship and mobility of zooplankton taxa from a subtropical location (Ubatuba, Brazil). Lethal effects were observed in five out of six taxa investigated, three of which (copepod nauplii, tintinnids and gastropod larvae) when exposed to dinoflagellate exudates and two (rotifers and brachyuran zoeae) when exposed to intact cells. In addition, gastropod larvae displayed mobility impairment during exposure to dinoflagellate exudates. Only polychaete larvae were not apparently affected during the course of the experiments. Zooplankton responses usually varied according to the dinoflagellate species tested. For instance, exudates from Alexandrium tamiyavanichii, Gonyaulax sp. and Gymnodinium sp. decreased survivorship of planktonic copepod nauplii but did not affect bottom-dwelling harpacticoid nauplii, which were in turn killed by exudates from Prorocentrum lima, a epibenthic dinoflagellate. These results suggest that HAB events do not cause indiscriminate zooplankton mortality, but may instead generate community shifts and complex cascading effects through the pelagic and benthic food web. Species-specific monitoring of zooplankton responses to HABs is therefore an important step to understand the ecological implications of dinoflagellate outbreaks in coastal waters, and their impact on marine farming activities

    Essential genetic findings in neurodevelopmental disorders

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    Neurodevelopmental disorders (NDDs) represent a growing medical challenge in modern societies. Ever-increasing sophisticated diagnostic tools have been continuously revealing a remarkably complex architecture that embraces genetic mutations of distinct types (chromosomal rearrangements, copy number variants, small indels, and nucleotide substitutions) with distinct frequencies in the population (common, rare, de novo). Such a network of interacting players creates difficulties in establishing rigorous genotype-phenotype correlations. Furthermore, individual lifestyles may also contribute to the severity of the symptoms fueling a large spectrum of gene-environment interactions that have a key role on the relationships between genotypes and phenotypes.Herein, a review of the genetic discoveries related to NDDs is presented with the aim to provide useful general information for the medical community.This work was financed by FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 - Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT - Fundação para a CiĂȘncia e a Tecnologia, in the framework of the project POCI-01-0145-FEDER-007274 to i3S and UID/ BIM/04501/2013 and UID/BIM/04501/2019 to iBiMED, as well as by national funds (OE), through FCT, in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19 to RMS, and by FCT research project POCI-01-0145-FEDER-29723. ARC and CS hold FCT PhD fellowships (SFRH/BD/141702/2018-ARC and SFRH/BD/137925/2018-CS). Funders had no role in the design, collection, analysis, interpretation of the data, and writing of the manuscript

    Delivering amoxicillin at the infection site-a rational design through lipid nanoparticles

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    Purpose: Amoxicillin is a commonly used antibiotic, although degraded by the acidic pH of the stomach. This is an important limitation for the treatment of Helicobacter pylori infections. The purpose of this work was to encapsulate amoxicillin in lipid nanoparticles, increasing the retention time at the site of infection (gastric mucosa), while protecting the drug from the harsh conditions of the stomach lumen. Materials and methods: The nanoparticles were produced by the double emulsion technique and optimized by a three-level Box-Behnken design. Tween 80 and linolenic acid were used as potential therapeutic adjuvants and dioleoylphosphatidylethanolamine as a targeting agent to Helicobacter pylori. Nanoparticles were characterized regarding their physico-chemical features, their storage stability, and their usability for oral administration (assessment of in vitro release, in vitro cell viability, permeability, and interaction with mucins). Results: The nanoparticles were stable for at least 6 months at 4°C. In vitro release studies revealed a high resistance to harsh conditions, including acidic pH and physiologic temperature. The nanoparticles have a low cytotoxicity effect in both fibroblasts and gastric cell lines, and they have the potential to be retained at the gastric mucosa. Conclusion: Overall, the designed formulations present suitable physico-chemical features for being henceforward used by oral administration to treat Helicobacter pylori infections.DLC, RMP, TS, and CN are thankful to Fundação para a CiĂȘncia e Tecnologia (FCT) for the PhD Grant (PD/ BD/105957/2014), Research Grant (PD/BI/128326/2017), post-doctorate grant (SFRH/BPD/103113/2014), and Investigator Grant (IF/00293/2015), respectively. This work was supported by FCT through the FCT PhD Programmes and by Programa Operacional Capital Humano (POCH), specifically by the BiotechHealth Programe (Doctoral Programme on Cellular and Molecular Biotechnology Applied to Health Sciences). The authors are also grateful to Dr Rui Fernandes (Histology and Electron Microscopy Service – Instituto de Investigação e Inovação em SaĂșde, Universidade do Porto) for the expertise and technical assistance with transmission electron microscopy and to Manuela Barros for administrative and technical support. The authors thank the financial support under Program PT2020 (UID/QUI/50006/2019). SACL and BS thanks Operação NORTE-01-0145-FEDER-000011 and NORTE-01-0145-FEDER-000012, respectively, for their Investigator contract

    Improved algorithm for neuronal ensemble inference by Monte Carlo method

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    Neuronal ensemble inference is one of the significant problems in the study of biological neural networks. Various methods have been proposed for ensemble inference from their activity data taken experimentally. Here we focus on Bayesian inference approach for ensembles with generative model, which was proposed in recent work. However, this method requires large computational cost, and the result sometimes gets stuck in bad local maximum solution of Bayesian inference. In this work, we give improved Bayesian inference algorithm for these problems. We modify ensemble generation rule in Markov chain Monte Carlo method, and introduce the idea of simulated annealing for hyperparameter control. We also compare the performance of ensemble inference between our algorithm and the original one.Comment: 14 pages, 3 figure

    A fixed point formula for the index of multi-centered N=2 black holes

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    We propose a formula for computing the (moduli-dependent) contribution of multi-centered solutions to the total BPS index in terms of the (moduli-independent) indices associated to single-centered solutions. The main tool in our analysis is the computation of the refined index Tr(-y)^{2J_3} of configurational degrees of freedom of multi-centered BPS black hole solutions in N=2 supergravity by localization methods. When the charges carried by the centers do not allow for scaling solutions (i.e. solutions where a subset of the centers can come arbitrarily close to each other), the phase space of classical BPS solutions is compact and the refined index localizes to a finite set of isolated fixed points under rotations, corresponding to collinear solutions. When the charges allow for scaling solutions, the phase space is non-compact but appears to admit a compactification with finite volume and additional non-isolated fixed points. We give a prescription for determining the contributions of these fixed submanifolds by means of a `minimal modification hypothesis', which we prove in the special case of dipole halo configurations.Comment: 61 pages, 3 figure
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