486 research outputs found
New detrital petrographic and thermochronologic constraints on the Late Cretaceous-Neogene erosional history of the equatorial margin of Brazil: Implications for the surface evolution of a complex rift margin
The equatorial margin of Brazil is an example of a rift margin with a complex landscape, dominated by an escarpment perpendicular to the continental margin, which testifies to an equally complex rift and post-rift surface and tectonic evolution. This has been the focus of a long debate on the driving mechanism for post-rift tectonics and on the amount of exhumation. This study contributes to this debate with new petrographic and thermochronologic data on 152 samples from three basins, Para-Maranhao, Barreirinhas and Ceara, on the offshore continental platform. Our detrital record goes back to the rift time at ca. 100 Ma ago and outlines three major evolutionary phases of a changing landscape: a rift phase, with the erosion of a moderate rift escarpment, a Late Cretaceous-Palaeogene post-rift phase of major drainage reorganization and significant vertical erosion and a Late Oligocene-to-Recent post-rift phase of moderate vertical erosion and river headwater migration. We estimate that along the equatorial margin of Brazil, over a large onshore area, exhumation since the Late Cretaceous has totalled locally up to 2-2.5 km and since the late Oligocene did not exceed 1 km
Reciprocal Tripartite Interactions between the Aedes aegypti Midgut Microbiota, Innate Immune System and Dengue Virus Influences Vector Competence
Dengue virus is one of the most important arboviral pathogens and the causative agent of dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. It is transmitted between humans by the mosquitoes Aedes aegypti and Aedes albopictus, and at least 2.5 billion people are at daily risk of infection. During their lifecycle, mosquitoes are exposed to a variety of microbes, some of which are needed for their successful development into adulthood. However, recent studies have suggested that the adult mosquito's midgut microflora is critical in influencing the transmission of human pathogens. In this study we assessed the reciprocal interactions between the mosquito's midgut microbiota and dengue virus infection that are, to a large extent, mediated by the mosquito's innate immune system. We observed a marked decrease in susceptibility to dengue virus infection when mosquitoes harbored certain field-derived bacterial isolates in their midgut. Transcript abundance analysis of selected antimicrobial peptide genes suggested that the mosquito's microbiota elicits a basal immune activity that appears to act against dengue virus infection. Conversely, the elicitation of the mosquito immune response by dengue virus infection itself influences the microbial load of the mosquito midgut. In sum, we show that the mosquito's microbiota influences dengue virus infection of the mosquito, which in turn activates its antibacterial responses
Sustainability and Corporate Social Responsibility in the Perspective of Social Economy Entities: A Bibliometric Study
We start from the conceptual interconnection between Sustainability and Corporate Social Responsibility, which, although continuously subject to controversy, both within the scope of its definition and in its performance, advocate, as the ultimate goal, human development and of the society in general, promoting the interests of the Communities on a permanent, long-term basis and without compromising the options of the future generations. In this context, we cannot fail to draw a parallel with the entities that constitute the Social Economy Sector. The activities they carry out are of economic and social nature and must be pursued in the general interest of their members, users and beneficiaries, thus in the general interest of the Community. These institutions also reveal concerns about the sustainability in all the dimensions involved (economic, social and environmental), in which the organizational performance is particularly important, as it becomes imperative to guarantee their continuity, fostering and promoting their social action. We will, therefore, start by framing what is meant by Sustainability, Corporate Social Responsibility and Social Economy, with a particular focus on the current requirements of stakeholders regarding the socially responsible behaviour of the institutions as these, in turn, will entail the adoption of more comprehensive management tools, also more efficient and transparent concerning all dimensions (economic, financial and social). It is within this framework that a project called “TFA—TheoFrameAccountability—Theoretical framework for the promotion of accountability in the social economy sector: The IPSS case” emerges, being promoted by the University of Aveiro, with the participation of National Confederation of Solidarity Institutions (CNIS—acronym in Portuguese), and the Polytechnic Institutes of Coimbra and Porto. This project aims to promote the accountability of the social economy sector (economic, financial and social aspects), in the Private Social Solidarity Institutions (IPSS—acronym in Portuguese), assisting them not only in fulfilling their legal obligations, but also facilitating the reporting of results of activities carried out in a more effective manner and promoting transfer of knowledge (for the IPSS and also for the academic community), thus contributing to the development and sustainability of these institutions. Thus, we develop an exploratory and descriptive analysis, of a quantitative-qualitative nature, in which the procedures of data collection determine the result of the search strategy by the defined descriptors. For this purpose, the analysis will focus on the following variables: number of articles published per year; methodologies used; theories of support; identification by sector/area of activity; countries of origin; more representative institutions; authors who publish more and journals with the largest number of publications. The main results indicate a growing concern about sustainability and a growing publication in this area. This paper presents a bibliometric study to evaluate the main trends of current research on sustainability and on corporate social responsibility, thus contributing to the construction of the theoretical basis underlying the “TFA—TheoFrameAccountability” project.info:eu-repo/semantics/publishedVersio
Benznidazole biotransformation and multiple targets in <i>Trypanosoma</i> cruzi revealed by metabolomics
<b>Background</b><p></p>
The first line treatment for Chagas disease, a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, involves administration of benznidazole (Bzn). Bzn is a 2-nitroimidazole pro-drug which requires nitroreduction to become active, although its mode of action is not fully understood. In the present work we used a non-targeted MS-based metabolomics approach to study the metabolic response of T. cruzi to Bzn.<p></p>
<b>Methodology/Principal findings</b><p></p>
Parasites treated with Bzn were minimally altered compared to untreated trypanosomes, although the redox active thiols trypanothione, homotrypanothione and cysteine were significantly diminished in abundance post-treatment. In addition, multiple Bzn-derived metabolites were detected after treatment. These metabolites included reduction products, fragments and covalent adducts of reduced Bzn linked to each of the major low molecular weight thiols: trypanothione, glutathione, γ-glutamylcysteine, glutathionylspermidine, cysteine and ovothiol A. Bzn products known to be generated in vitro by the unusual trypanosomal nitroreductase, TcNTRI, were found within the parasites, but low molecular weight adducts of glyoxal, a proposed toxic end-product of NTRI Bzn metabolism, were not detected.<p></p>
<b>Conclusions/significance</b><p></p>
Our data is indicative of a major role of the thiol binding capacity of Bzn reduction products in the mechanism of Bzn toxicity against T. cruzi
Protective Human Leucocyte Antigen Haplotype, HLA-DRB1*01-B*14, against Chronic Chagas Disease in Bolivia
Chronic Chagas disease consists of four different forms categorized on the basis of their clinical manifestations, namely; cardiac, digestive, cardiodigestive and indeterminate. In Latin America, there are 8–10 million seropositive persons who are at risk of, or have already developed serious clinical complications and who have limited access to effective treatment. The cardiac and digestive forms are characterized by tissue damage caused by persistent infection of Trypanosoma cruzi and are thought to be modulated by host immunity. In our large scale screening for chronic Chagas disease in Santa Cruz, Bolivia, hearts and colons of 229 seropositive patients were examined. We found 31.4% of patients had abnormal electrocardiograms (ECGs), 15.7% presented with megacolon, 5.2% had a combination of abnormal ECG and megacolon, and 58.1% were of indeterminate status. Previously, we attempted to ascertain whether parasite genetic polymorphism might account for the differences in clinical manefestations, by analyzing parasite DNA taken from the same study group (with the addition of a further 62 megacolon post-operational patients). We found no relationships between parasite lineages and clinical disease form. The present study reveals that host HLA polymorphisms associate with clinical manifestations of Chagas
Prevalence of transfusion-transmitted Chagas disease among multitransfused patients in Brazil
<p>Abstract</p> <p>Background</p> <p>Blood transfusion has always been an important route for Chagas Disease (CD) transmission. The high prevalence of CD in Latin America and its lifelong asymptomatic clinical picture pose a threat for the safety of the blood supply. The outcome of measures designed to improve transfusion safety can be assessed by evaluating the prevalence of CD among multitransfused patients</p> <p>Methods</p> <p>In order to assess the impact of CD control measures on the safety of the blood supply, an observational cross-sectional study was designed to determine the prevalence of CD in 351 highly transfused patients, in which vectorial transmission was excluded. This study compared patients that received transfusion products before (n = 230) and after (n = 121) 1997, when measures to control transfusion-transmitted CD were fully implemented in Brazil.</p> <p>Results</p> <p>The study group consisted of 351 patients exposed to high numbers of blood products during their lifetime (median number of units transfused = 51, range 10–2086). A higher prevalence of transfusion-transmitted CD (1.30%) was observed among multitransfused patients that received their first transfusion before 1997, compared with no cases of transfusion-transmitted CD among multitransfused patients transfused after that year. The magnitude of the exposure to blood products was similar among both groups (mean number of units transfused per year of exposure = 25.00 ± 26.46 and 23.99 ± 30.58 respectively; P = 0.75, Mann-Whitney test).</p> <p>Conclusion</p> <p>Multiple initiatives aimed to control vector and parental transmission of CD can significantly decrease transfusion-transmitted CD in Brazil. Our data suggest that mandatory donor screening for CD represents the most important measure to interrupt transmission of CD by blood transfusions.</p
Phenoloxidase activity acts as a mosquito innate immune response against infection with semliki forest virus
Several components of the mosquito immune system including the RNA interference (RNAi), JAK/STAT, Toll and IMD pathways have previously been implicated in controlling arbovirus infections. In contrast, the role of the phenoloxidase (PO) cascade in mosquito antiviral immunity is unknown. Here we show that conditioned medium from the Aedes albopictus-derived U4.4 cell line contains a functional PO cascade, which is activated by the bacterium Escherichia coli and the arbovirus Semliki Forest virus (SFV) (Togaviridae; Alphavirus). Production of recombinant SFV expressing the PO cascade inhibitor Egf1.0 blocked PO activity in U4.4 cell- conditioned medium, which resulted in enhanced spread of SFV. Infection of adult female Aedes aegypti by feeding mosquitoes a bloodmeal containing Egf1.0-expressing SFV increased virus replication and mosquito mortality. Collectively, these results suggest the PO cascade of mosquitoes plays an important role in immune defence against arboviruses
Estimation of lung vital capacity before and after coronary artery bypass grafting surgery: a comparison of incentive spirometer and ventilometry
<p>Abstract</p> <p>Background</p> <p>Measurement of vital capacity (VC) by spirometry is the most widely used technique for lung function evaluation, however, this form of assessment is costly and further investigation of other reliable methods at lower cost is necessary. Objective: To analyze the correlation between direct vital capacity measured with ventilometer and with incentive inspirometer in patients in pre and post cardiac surgery.</p> <p>Methodology</p> <p>Cross-sectional comparative study with patients undergoing cardiac surgery. Respiratory parameters were evaluated through the measurement of VC performed by ventilometer and inspirometer. To analyze data normality the Kolmogorov-Smirnov test was applied, for correlation the Pearson correlation coefficient was used and for comparison of variables in pre and post operative period Student's t test was adopted. We established a level of ignificance of 5%. Data was presented as an average, standard deviation and relative frequency when needed. The significance level was set at 5%.</p> <p>Results</p> <p>We studied 52 patients undergoing cardiac surgery, 20 patients in preoperative with VC-ventilometer: 32.95 ± 11.4 ml/kg and VC-inspirometer: 28.9 ± 11 ml/Kg, r = 0.7 p < 0.001. In the post operatory, 32 patients were evaluated with VC-ventilometer: 28.27 ± 12.48 ml/kg and VC-inspirometer: 26.98 ± 11 ml/Kg, r = 0.95 p < 0.001. Presenting a very high correlation between the evaluation forms studied.</p> <p>Conclusion</p> <p>There was a high correlation between DVC measures with ventilometer and incentive spirometer in pre and post CABG surgery. Despite this, arises the necessity of further studies to evaluate the repercussion of this method in lowering costs at hospitals.</p
- …