20 research outputs found

    The Amazon Epiphyte Network: A First Glimpse Into Continental-Scale Patterns of Amazonian Vascular Epiphyte Assemblages

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    Epiphytes are still an understudied plant group in Amazonia. The aim of this study was to identify distributional patterns and conservation priorities for vascular epiphyte assemblages (VEA) across Amazonia. We compiled the largest Amazonian epiphyte plot database to date, through a multinational collaborative effort of 22 researchers and 32 field sites located across four Amazonian countries – the Amazonian Epiphyte Network (AEN). We addressed the following continental-scale questions by utilizing the AEN database comprising 96,448 epiphyte individuals, belonging to 518 vascular taxa, and growing on 10,907 tree individuals (phorophytes). Our objectives here are, first, to present a qualitative evaluation of the geographic distribution of the study sites and highlight regional lacunae as priorities for future quantitative inventories. Second, to present the floristic patterns for Amazonia-wide VEA and third, to combine multivariate analyses and rank abundance curves, controlled by major Amazonian habitat types, to determine how VEA vary geographically and ecologically based on major Amazonian habitat types. Three of the most striking patterns found are that: (1) VEA are spatially structured as floristic similarity decays with geographic distance; (2) a core group of 22 oligarchic taxa account for more than a half of all individuals; and (3) extensive floristic sampling gaps still exist, mainly across the highly threatened southern Amazonian deforestation belt. This work represents a first step toward unveiling distributional pattern of Amazonian VEA, which is important to guide future questions on ecology and species distribution ranges of VEA once the collaborative database grows allowing a clearer view of patterns

    Compound A, a Dissociated Glucocorticoid Receptor Modulator, Inhibits T-bet (Th1) and Induces GATA-3 (Th2) Activity in Immune Cells

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    Background: Compound A (CpdA) is a dissociating non-steroidal glucocorticoid receptor (GR) ligand which has antiinflammatory properties exerted by down-modulating proinflammatory gene expression. By favouring GR monomer formation, CpdA does not enhance glucocorticoid (GC) response element-driven gene expression, resulting in a reduced side effect profile as compared to GCs. Considering the importance of Th1/Th2 balance in the final outcome of immune and inflammatory responses, we analyzed how selective GR modulation differentially regulates the activity of T-bet and GATA-3, master drivers of Th1 and Th2 differentiation, respectively. Results: Using Western analysis and reporter gene assays, we show in murine T cells that, similar to GCs, CpdA inhibits T-bet activity via a transrepressive mechanism. Different from GCs, CpdA induces GATA-3 activity by p38 MAPK-induction of GATA-3 phosphorylation and nuclear translocation. CpdA effects are reversed by the GR antagonist RU38486, proving the involvement of GR in these actions. ELISA assays demonstrate that modulation of T-bet and GATA-3 impacts on cytokine production shown by a decrease in IFN-c and an increase in IL-5 production, respectively. Conclusions: Taken together, through their effect favoring Th2 over Th1 responses, particular dissociated GR ligands, fo

    Identification of a BRCA2-Specific Modifier Locus at 6p24 Related to Breast Cancer Risk

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    Identification of a BRCA2-Specific modifier locus at 6p24 related to breast cancer risk

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    Common genetic variants contribute to the observed variation in breast cancer risk for BRCA2 mutation carriers; those known to date have all been found through population-based genome-wide association studies (GWAS). To comprehensively identify breast cancer risk modifying loci for BRCA2 mutation carriers, we conducted a deep replication of an ongoing GWAS discovery study. Using the ranked P-values of the breast cancer associations with the imputed genotype of 1.4 M SNPs, 19,029 SNPs were selected and designed for inclusion on a custom Illumina array that included a total of 211,155 SNPs as part of a multi-consortial project. DNA samples from 3,881 breast cancer affected and 4,330 unaffected BRCA2 mutation carriers from 47 studies belonging to the Consortium of Investigators of Modifiers of BRCA1/2 were genotyped and available for analysis. We replicated previously reported breast cancer susceptibility alleles in these BRCA2 mutation carriers and for several regions (including FGFR2, MAP3K1, CDKN2A/B, and PTHLH) identified SNPs that have stronger evidence of association than those previously published. We also identified a novel susceptibility allele at 6p24 that was inversely associated with risk in BRCA2 mutation carriers (rs9348512; per allele HR = 0.85, 95% CI 0.80-0.90, P = 3.9×10−8). This SNP was not associated with breast cancer risk either in the general population or in BRCA1 mutation carriers. The locus lies within a region containing TFAP2A, which encodes a transcriptional activation protein that interacts with several tumor suppressor genes. This report identifies the first breast cancer risk locus specific to a BRCA2 mutation background. This comprehensive update of novel and previously reported breast cancer susceptibility loci contributes to the establishment of a panel of SNPs that modify breast cancer risk in BRCA2 mutation carriers. This panel may have clinical utility for women with BRCA2 mutations weighing options for medical prevention of breast cancer

    DFT-INDO/S modeling of new high molar extinction coefficient charge-transfer sensitizers for solar cell applications

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    A new Ru(II) complex, Bu4N [ruthenium (4-carboxylic acid-4'-carboxylate-2,2'-bipyridine)(4,4'-di(2-(3,6-dimethoxyphenyl)ethenyl)-2,2'-bipyridine)(NCS)2] (N945H), was synthesized and characterized by anal., spectroscopic, and electrochem. techniques. The absorption spectrum of the N945H sensitizer is dominated by metal-to-ligand charge-transfer (MLCT) transitions in the visible region, with the lowest allowed MLCT bands appearing at 25,380 and 18,180 cm-1. The molar absorptivities of these bands are 34,500 and 18,900 M-1 cm-1, resp., and are significantly higher when compared to than those of the std. sensitizer cis-dithiocyanatobis(4,4'-dicarboxylic acid-2,2'-bipyridine)ruthenium(II). An INDO/S and DFT study of the electronic and optical properties of N945H and of N945 adsorbed on TiO2 was performed. The calcns. point out that the top 3 frontier-filled orbitals have a Ru 4d (t2g in the octahedral group) character with a contribution coming from the NCS ligand orbitals. The calcns. also reveal that in the TiO2-bound N945 sensitizer, excitation directs charge into the carboxylbipyridine ligand bound to the TiO2 surface. The photovoltaic data of the N945 sensitizer using an electrolyte contg. 0.60M butylmethylimidazolium iodide, 0.03M I2, 0.10M guanidinium thiocyanate, and 0.50M tert-butylpyridine in a mixt. of MeCN and valeronitrile (vol. ratio = 85:15) had a short-circuit photocurrent d. of 16.50 ± 0.2 mA/cm2, an open-circuit voltage of 790 ± 30 mV, and a fill factor of 0.72 ± 0.03. This corresponds to an overall conversion efficiency of 9.6% under std. AM 1.5 sunlight and stable performance under light and heat soaking at 80° was confirmed

    Cerebral ischemia caused by Streptococcus bovis aortic endocarditis: case report Isquemia cerebral causada por endocardite aórtica pelo Streptococcus bovis: relato de caso

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    Cerebral ischemic processes associated with infective endocarditis caused by Streptococcus bovis are rare; only 2 cases having been reported. Here we report a case of a 50-year-old man with S. bovis endocarditis who presented signs of frontal, parietal and occipital lobe cerebral ischemia. This is the first case reported in which the presence of hemianopsia preceded the endocarditis diagnosis. Initially, the clinical manifestations suggested a systemic vasculitis. Later, vegetating lesions were identified in the aortic valve and S. bovis grew in blood cultures. Antibiotic use and aortic valve replacement eliminated the infection and ceased thromboembolic events. A videocolonoscopy examination revealed no mucosal lesions as a portal of entry in this case, although such lesions have been encountered in up to 70% of reported cases of S. bovis endocarditis.<br>A associação de isquemia cerebral e endocardite por Streptococcus bovis é um evento raro, tendo sido publicados apenas 2 casos anteriormente. Nós relatamos o caso de um homem de 50 anos com endocardite por S. bovis que apresentou sinais isquêmicos nos lobos frontal, parietal e occipital. Este é o primeiro caso em que a hemianopsia precedeu o diagnóstico de endocardite. Inicialmente, o quadro foi confundido com vasculite. Posteriormente, foi confirmada a presença de vegetações na válvula aórtica e a hemocultura identificou S. bovis. Os eventos tromboembólicos foram controlados com o uso de antibióticos e a troca da válvula aórtica. Estudo videocolonoscópico não identificou nenhuma lesão, apesar de lesões colônicas serem descritas em até 70% dos casos de indivíduos com endocardite por S. bovis

    Gender differences in clinical outcomes among HIV-positive individuals on antiretroviral therapy in Canada: a multisite cohort study

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    Background: Cohort data examining differences by gender in clinical responses to combination antiretroviral therapy (ART) remain inconsistent and have yet to be explored in a multi-province Canadian setting. This study investigates gender differences by injection drug use (IDU) history in virologic responses to ART and mortality. Methods: Data from the Canadian Observational Cohort (CANOC) collaboration, a multisite cohort study of HIV-positive individuals initiating ART after January 1, 2000, were included. This analysis was restricted to participants with a follow-up HIV-RNA plasma viral load measure and known IDU history. Weibull hazard regression evaluated time to virologic suppression (2 consecutive measures 1000 copies/mL after suppression), and all-cause mortality. Sensitivity analyses explored the impact of presumed ART use in pregnancy on virologic outcomes. Results: At baseline, women (1120 of 5442 participants) were younger (median 36 vs. 41 years) and more frequently reported IDU history (43.5% vs. 28.8%) (both
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