104 research outputs found

    Interference with Hemozoin Formation Represents an Important Mechanism of Schistosomicidal Action of Antimalarial Quinoline Methanols

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    Heme is an essential molecule to most living organisms, but once in a free state it exerts toxic effects. Blood-feeding organisms evolved efficient ways to detoxify free heme derived from hemoglobin digestion. A key mechanism present in some hematophagous organisms consists of the crystallization of heme into a pigment named hemozoin. Schistosoma mansoni is one of the etiologic agents of human schistosomiasis, a parasitic disease that affects over 200 million people in tropical and subtropical areas. Hemozoin formation represents the main heme detoxification pathway in S. mansoni. Here, we report that the antimalarial quinoline methanols quinine and quinidine exert schistosomicidal effects notably due to their capacity to interfere with hemozoin formation. When quinine or quinidine were administered intraperitoneally during seven days to S. mansoni-infected mice (75 mg/kg/day), both worm and eggs burden were significantly reduced. Interestingly, hemozoin content in female worms was drastically affected after treatment with either compound. We also found that quinine caused important changes in the cellular organization of worm gastrodermis and increased expression of genes related to musculature, protein synthesis and repair mechanisms. Together, our results indicate that interference with hemozoin formation is a valid chemotherapeutic target for development of new schistosomicidal agents

    Granulocyte-Colony Stimulating Factor-Overexpressing Mesenchymal Stem Cells Exhibit Enhanced Immunomodulatory Actions Through the Recruitment of Suppressor Cells in Experimental Chagas Disease Cardiomyopathy

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    Genetic modification of mesenchymal stem cells (MSCs) is a promising strategy to improve their therapeutic effects. Granulocyte-colony stimulating factor (G-CSF) is a growth factor widely used in the clinical practice with known regenerative and immunomodulatory actions, including the mobilization of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs). Here we evaluated the therapeutic potential of MSCs overexpressing G-CSF (MSC_G-CSF) in a model of inflammatory cardiomyopathy due to chronic Chagas disease. C57BL/6 mice were treated with wild-type MSCs, MSC_G-CSF, or vehicle (saline) 6 months after infection with Trypanosoma cruzi. Transplantation of MSC_G-CSF caused an increase in the number of circulating leukocytes compared to wild-type MSCs. Moreover, G-CSF overexpression caused an increase in migration capacity of MSCs to the hearts of infected mice. Transplantation of either MSCs or MSC_G-CSF improved exercise capacity, when compared to saline-treated chagasic mice. MSC_G-CSF mice, however, were more potent than MSCs in reducing the number of infiltrating leukocytes and fibrosis in the heart. Similarly, MSC_G-CSF-treated mice presented significantly lower levels of inflammatory mediators, such as IFNγ, TNFα, and Tbet, with increased IL-10 production. A marked increase in the percentage of Tregs and MDSCs in the hearts of infected mice was seen after administration of MSC_G-CSF, but not MSCs. Moreover, Tregs were positive for IL-10 in the hearts of T. cruzi-infected mice. In vitro analysis showed that recombinant hG-CSF and conditioned medium of MSC_G-CSF, but not wild-type MSCs, induce chemoattraction of MDSCs in a transwell assay. Finally, MDSCs purified from hearts of MSC_G-CSF transplanted mice inhibited the proliferation of activated splenocytes in a co-culture assay. Our results demonstrate that G-CSF overexpression by MSCs potentiates their immunomodulatory effects in our model of Chagas disease and suggest that mobilization of suppressor cell populations such as Tregs and MDSCs as a promising strategy for the treatment of chronic Chagas disease. Finally, our results reinforce the therapeutic potential of genetic modification of MSCs, aiming at increasing their paracrine actions

    Pharmacological activity of the hydroalcoholic extract from Hovenia dulcis thunberg fruit and the flavonoid dihydromyricetin during hypercholesterolemia induced in rats

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    Cerebrovascular accidents and coronary artery disease are the leading causes of cardiovascular mortalities in Brazil and high levels of LDL cholesterol are one of the main risk factors. In this context, several plant extracts and natural substances have shown promise as cholesterol-lowering. The objective of this study was to evaluate the potential of the hydroalcoholic extract of the fruit of H. dulcisand of dihydromyricetin in cholesterol reduction in hypercholesterolemic rats. Forty-two Wistar male rats were distributed into seven groups of six animals that received diets supplemented with 1% cholesterol and 0.3% cholic acid, with the exception of the control group, which received conventional diets. Animals were treated with oral suspensions containing: atorvastatin 1.0 mg/kg; H. dulcisextract at 50.0 and 100.0 mg/kg and dihydromyricetin at 25.0 and 50.0 mg/kg vehicle (control group). The following biochemical markers were evaluated; total cholesterol, HDL-C, LDL-C, triglycerides, AST, ALT, and alkaline phosphatase. The hypercholesterolemic diet was effective in inducing hypercholesterolemia, increasing total cholesterol by 112.7% relative to the control group. The treatments with two doses of the extract proved to be promising hypocholesterolemic agents, as they were able to substantially reduce total cholesterol and LDL-C, without significantly altering triglycerides, hepatic transaminases, and alkaline phosphatase, thereby encouraging the studies with the plant H. dulcis. The groups treated with the flavonoid dihydromyricetin, although they showed a significant reduction in total cholesterol and LDL-C, and found increases in triglycerides and hepatic transaminases, which is unwanted in the context of hypercholesterolaemia

    Evidence for Reductive Genome Evolution and Lateral Acquisition of Virulence Functions in Two Corynebacterium pseudotuberculosis Strains

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    Ruiz JC, D'Afonseca V, Silva A, et al. Evidence for Reductive Genome Evolution and Lateral Acquisition of Virulence Functions in Two Corynebacterium pseudotuberculosis Strains. PLoS ONE. 2011;6(4): e18551.Background: Corynebacterium pseudotuberculosis, a Gram-positive, facultative intracellular pathogen, is the etiologic agent of the disease known as caseous lymphadenitis (CL). CL mainly affects small ruminants, such as goats and sheep; it also causes infections in humans, though rarely. This species is distributed worldwide, but it has the most serious economic impact in Oceania, Africa and South America. Although C. pseudotuberculosis causes major health and productivity problems for livestock, little is known about the molecular basis of its pathogenicity. Methodology and Findings: We characterized two C. pseudotuberculosis genomes (Cp1002, isolated from goats; and CpC231, isolated from sheep). Analysis of the predicted genomes showed high similarity in genomic architecture, gene content and genetic order. When C. pseudotuberculosis was compared with other Corynebacterium species, it became evident that this pathogenic species has lost numerous genes, resulting in one of the smallest genomes in the genus. Other differences that could be part of the adaptation to pathogenicity include a lower GC content, of about 52%, and a reduced gene repertoire. The C. pseudotuberculosis genome also includes seven putative pathogenicity islands, which contain several classical virulence factors, including genes for fimbrial subunits, adhesion factors, iron uptake and secreted toxins. Additionally, all of the virulence factors in the islands have characteristics that indicate horizontal transfer. Conclusions: These particular genome characteristics of C. pseudotuberculosis, as well as its acquired virulence factors in pathogenicity islands, provide evidence of its lifestyle and of the pathogenicity pathways used by this pathogen in the infection process. All genomes cited in this study are available in the NCBI Genbank database (http://www.ncbi.nlm.nih.gov/genbank/) under accession numbers CP001809 and CP001829

    Redshift distributions of galaxies in the Dark Energy Survey Science Verification shear catalogue and implications for weak lensing

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    We present photometric redshift estimates for galaxies used in the weak lensing analysis of the Dark Energy Survey Science Verification (DES SV) data. Four model- or machine learning-based photometric redshift methods—ANNZ2, BPZ calibrated against BCC-Ufig simulations, SKYNET, and TPZ—are analyzed. For training, calibration, and testing of these methods, we construct a catalogue of spectroscopically confirmed galaxies matched against DES SV data. The performance of the methods is evaluated against the matched spectroscopic catalogue, focusing on metrics relevant for weak lensing analyses, with additional validation against COSMOS photo-z’s. From the galaxies in the DES SV shear catalogue, which have mean redshift 0.72 0.01 over the range 0.3 < z < 1.3, we construct three tomographic bins with means of z ¼ f0.45; 0.67; 1.00g. These bins each have systematic uncertainties δz ≲ 0.05 in the mean of the fiducial SKYNET photo-z nðzÞ. We propagate the errors in the redshift distributions through to their impact on cosmological parameters estimated with cosmic shear, and find that they cause shifts in the value of σ8 of approximately 3%. This shift is within the one sigma statistical errors on σ8 for the DES SV shear catalogue. We further study the potential impact of systematic differences on the critical surface density, Σcrit, finding levels of bias safely less than the statistical power of DES SV data. We recommend a final Gaussian prior for the photo-z bias in the mean of nðzÞ of width 0.05 for each of the three tomographic bins, and show that this is a sufficient bias model for the corresponding cosmology analysis

    Avaliação da transferência de citocinas para bezerros neonatos via ingestão de colostro de fêmeas bovinas Holandesas

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    Para a avaliação da transferência de citocinas para o sangue de bezerros neonatos via ingestão de colostro de fêmeas bovinas holandesas, foram utilizados 15 bezerros nascidos de parto eutócico, distribuídos igualmente por três grupos experimentais (n=5): G1- receberam dois litros de colostro fresco provenientes de suas próprias mães; G2- receberam dois litros de colostro provenientes de "pool" de colostro congelado e o G3- foram alimentados apenas com leite. Nestes grupos foram coletadas amostras de sangue em cinco tempos durante os primeiros quinze dias de vida e mensuradas as concentrações das citocinas Interleucina-1 β (IL-1b), Interleucina-6 (IL-6), Fator de necrose tumoral- α (TNF-a) e Interferon-γ (IFN-γ). Também se mensurou tais citocinas (IL-1 β, IL-6 e TNF-α) nos sobrenadantes do colostro de do "pool" de colostro fornecidos aos bezerros dos grupos G1 e G2 respectivamente. Verificou-se a transferência das citocinas IL-1b, IL-6, TNF-a e IFN-γ pela presença no soro dos bezerros do grupo G1, enquanto que nos demais grupos (G2 e G3) não foram detectadas

    Genome of Herbaspirillum seropedicae Strain SmR1, a Specialized Diazotrophic Endophyte of Tropical Grasses

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    The molecular mechanisms of plant recognition, colonization, and nutrient exchange between diazotrophic endophytes and plants are scarcely known. Herbaspirillum seropedicae is an endophytic bacterium capable of colonizing intercellular spaces of grasses such as rice and sugar cane. The genome of H. seropedicae strain SmR1 was sequenced and annotated by The Paraná State Genome Programme—GENOPAR. The genome is composed of a circular chromosome of 5,513,887 bp and contains a total of 4,804 genes. The genome sequence revealed that H. seropedicae is a highly versatile microorganism with capacity to metabolize a wide range of carbon and nitrogen sources and with possession of four distinct terminal oxidases. The genome contains a multitude of protein secretion systems, including type I, type II, type III, type V, and type VI secretion systems, and type IV pili, suggesting a high potential to interact with host plants. H. seropedicae is able to synthesize indole acetic acid as reflected by the four IAA biosynthetic pathways present. A gene coding for ACC deaminase, which may be involved in modulating the associated plant ethylene-signaling pathway, is also present. Genes for hemagglutinins/hemolysins/adhesins were found and may play a role in plant cell surface adhesion. These features may endow H. seropedicae with the ability to establish an endophytic life-style in a large number of plant species

    Significant benefits of AIP testing and clinical screening in familial isolated and young-onset pituitary tumors

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    Context Germline mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene are responsible for a subset of familial isolated pituitary adenoma (FIPA) cases and sporadic pituitary neuroendocrine tumors (PitNETs). Objective To compare prospectively diagnosed AIP mutation-positive (AIPmut) PitNET patients with clinically presenting patients and to compare the clinical characteristics of AIPmut and AIPneg PitNET patients. Design 12-year prospective, observational study. Participants & Setting We studied probands and family members of FIPA kindreds and sporadic patients with disease onset ≤18 years or macroadenomas with onset ≤30 years (n = 1477). This was a collaborative study conducted at referral centers for pituitary diseases. Interventions & Outcome AIP testing and clinical screening for pituitary disease. Comparison of characteristics of prospectively diagnosed (n = 22) vs clinically presenting AIPmut PitNET patients (n = 145), and AIPmut (n = 167) vs AIPneg PitNET patients (n = 1310). Results Prospectively diagnosed AIPmut PitNET patients had smaller lesions with less suprasellar extension or cavernous sinus invasion and required fewer treatments with fewer operations and no radiotherapy compared with clinically presenting cases; there were fewer cases with active disease and hypopituitarism at last follow-up. When comparing AIPmut and AIPneg cases, AIPmut patients were more often males, younger, more often had GH excess, pituitary apoplexy, suprasellar extension, and more patients required multimodal therapy, including radiotherapy. AIPmut patients (n = 136) with GH excess were taller than AIPneg counterparts (n = 650). Conclusions Prospectively diagnosed AIPmut patients show better outcomes than clinically presenting cases, demonstrating the benefits of genetic and clinical screening. AIP-related pituitary disease has a wide spectrum ranging from aggressively growing lesions to stable or indolent disease course

    Profile of patients with rheumatic diseases undergoing treatment with anti-TNF agents in the Brazilian Public Health System (SUS), Belo Horizonte - MG

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    The aim of this study was to describe the baseline demographic and clinical characteristics as well as the functional status of a prospective cohort of patients with rheumatic diseases assisted by the Brazilian Public Health System (SUS). Data for 302 patients receiving tumor necrosis factor α inhibitors (anti-TNF agents) was collected through a standard form. Among patients, 229 (75.8%) were female and 155 (51.3%) were Caucasian; the mean age was 50.3 ± 12.8 years, and the mean disease duration was 9.9 ± 8.7 years. Among them 214 patients (70.9%) received adalimumab, 72 (23.8%) etanercept, and 16 (5.3%) infliximab. Mean Health Assessment Questionnaire-Disability Index (HAQ-DI) was 1.37 ± 0.67 for all participants. Poor functional response was associated with female gender, married patients and with a score of < 0.6 on the EuroQoL-5 dimensions (EQ-5D). Significant correlation was found between the HAQ-DI values, disease activity and quality of life (QOL). The results obtained in this study contribute to a better understanding of the clinical and demographic characteristics of patients with rheumatic diseases at the beginning of anti-TNF-agent treatment by SUS. Furthermore, our findings are consistent with another Brazilian and foreign cross-sectional investigations. This knowledge can be of great importance for further studies evaluating the effectiveness of biological agents, as well as, to contribute to improve the well-being of the patients with rheumatic diseases
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