553 research outputs found

    Contrasting environmental drivers of adult and juvenile growth in a marine fish: implications for the effects of climate change

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    Many marine fishes have life history strategies that involve ontogenetic changes in the use of coastal habitats. Such ontogenetic shifts may place these species at particular risk from climate change, because the successive environments they inhabit can differ in the type, frequency and severity of changes related to global warming. We used a dendrochronology approach to examine the physical and biological drivers of growth of adult and juvenile mangrove jack (Lutjanus argentimaculatus) from tropical north-western Australia. Juveniles of this species inhabit estuarine environments and adults reside on coastal reefs. The Niño-4 index, a measure of the status of the El Niño-Southern Oscillation (ENSO) had the highest correlation with adult growth chronologies, with La Niña years (characterised by warmer temperatures and lower salinities) having positive impacts on growth. Atmospheric and oceanographic phenomena operating at ocean-basin scales seem to be important correlates of the processes driving growth in local coastal habitats. Conversely, terrestrial factors influencing precipitation and river runoff were positively correlated with the growth of juveniles in estuaries. Our results show that the impacts of climate change on these two life history stages are likely to be different, with implications for resilience and management of populations

    Inhaled tobramycin solution-associated recurrent eosinophilia and severe persistent bronchospasm in a patient with cystic fibrosis: a case report

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    BACKGROUND: Delivery of tobramycin by inhalation to the lungs of patients with cystic fibrosis (CF) who are infected with Pseudomonas aeruginosa has been proven to be effective and safe. The aerosol administration allows high concentrations of tobramycin to be delivered to the site of infection with limited systemic absorption. In rare patients, systemic absorption of inhaled tobramycin may be significant enough to produce toxic effects, such as renal and vestibular toxicities. CASE PRESENTATION: We report a patient with CF who developed recurrent eosinophilia and severe persistent bronchospasm following repeated administration of preservative-free tobramycin by inhalation, beginning at 16 months of age. Also, he developed similar signs and symptoms when he was administered tobramycin intravenously on one occasion at 5 1/2 years. The patient had a history of environmental allergies. Temporal sequence of his signs and symptoms after each administration of tobramycin (similar to re-challenge testing), and his improvement after discontinuation of the drug strongly suggest an adverse drug reaction. CONCLUSION: Hypersensitivity reaction should be considered in patients who develop recurrent eosinophilia and deterioration of pulmonary function following the use of tobramycin by inhalation or by intravenous administration

    WWOX sensitises ovarian cancer cells to paclitaxel via modulation of the ER stress response

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    There are clear gaps in our understanding of genes and pathways through which cancer cells facilitate survival strategies as they become chemoresistant. Paclitaxel is used in the treatment of many cancers, but development of drug resistance is common. Along with being an antimitotic agent paclitaxel also activates endoplasmic reticulum (ER) stress. Here, we examine the role of WWOX (WW domain containing oxidoreductase), a gene frequently lost in several cancers, in mediating paclitaxel response. We examine the ER stress-mediated apoptotic response to paclitaxel in WWOX-transfected epithelial ovarian cancer (EOC) cells and following siRNA knockdown of WWOX. We show that WWOX-induced apoptosis following exposure of EOC cells to paclitaxel is related to ER stress and independent of the antimitotic action of taxanes. The apoptotic response to ER stress induced by WWOX re-expression could be reversed by WWOX siRNA in EOC cells. We report that paclitaxel treatment activates both the IRE-1 and PERK kinases and that the increase in paclitaxel-mediated cell death through WWOX is dependent on active ER stress pathway. Log-rank analysis of overall survival (OS) and progression-free survival (PFS) in two prominent EOC microarray data sets (Tothill and The Cancer Genome Atlas), encompassing ~800 patients in total, confirmed clinical relevance to our findings. High WWOX mRNA expression predicted longer OS and PFS in patients treated with paclitaxel, but not in patients who were treated with only cisplatin. The association of WWOX and survival was dependent on the expression level of glucose-related protein 78 (GRP78), a key ER stress marker in paclitaxel-treated patients. We conclude that WWOX sensitises EOC to paclitaxel via ER stress-induced apoptosis, and predicts clinical outcome in patients. Thus, ER stress response mechanisms could be targeted to overcome chemoresistance in cancer

    Adam33 polymorphisms are associated with COPD and lung function in long-term tobacco smokers

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    <p>Abstract</p> <p>Background</p> <p>Variation in ADAM33 has been shown to be important in the development of asthma and altered lung function. This relationship however, has not been investigated in the population susceptible to COPD; long term tobacco smokers. We evaluated the association between polymorphisms in ADAM33 gene with COPD and lung function in long term tobacco smokers.</p> <p>Methods</p> <p>Caucasian subjects, at least 50 year old, who smoked ≥ 20 pack-years (n = 880) were genotyped for 25 single nucleotide polymorphisms (SNPs) in ADAM33. COPD was defined as an FEV1/FVC ratio < 70% and percent-predicted (pp)FEV1 < 75% (n = 287). The control group had an FEV1/FVC ratio ≥ 70% and ppFEV<sub>1 </sub>≥ 80% (n = 311) despite ≥ 20 pack years of smoking. Logistic and linear regressions were used for the analysis. Age, sex, and smoking status were considered as potential confounders.</p> <p>Results</p> <p>Five SNPs in ADAM33 were associated with COPD (Q-1, intronic: p < 0.003; S1, Ile → Val: p < 0.003; S2, Gly → Gly: p < 0.04; V-1 intronic: p < 0.002; V4, in 3' untranslated region: p < 0.007). Q-1, S1 and V-1 were also associated with ppFEV1, FEV1/FVC ratio and ppFEF25–75 (p values 0.001 – 0.02). S2 was associated with FEV1/FVC ratio (p < 0.05). The association between S1 and residual volume revealed a trend toward significance (p value < 0.07). Linkage disequilibrium and haplotype analyses suggested that S1 had the strongest degree of association with COPD and pulmonary function abnormalities.</p> <p>Conclusion</p> <p>Five SNPs in ADAM33 were associated with COPD and lung function in long-term smokers. Functional studies will be needed to evaluate the biologic significance of these polymorphisms in the pathogenesis of COPD.</p

    Transcriptional activity of transposable elements in maize

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    <p>Abstract</p> <p>Background</p> <p>Mobile genetic elements represent a high proportion of the Eukaryote genomes. In maize, 85% of genome is composed by transposable elements of several families. First step in transposable element life cycle is the synthesis of an RNA, but few is known about the regulation of transcription for most of the maize transposable element families. Maize is the plant from which more ESTs have been sequenced (more than two million) and the third species in total only after human and mice. This allowed us to analyze the transcriptional activity of the maize transposable elements based on EST databases.</p> <p>Results</p> <p>We have investigated the transcriptional activity of 56 families of transposable elements in different maize organs based on the systematic search of more than two million expressed sequence tags. At least 1.5% maize ESTs show sequence similarity with transposable elements. According to these data, the patterns of expression of each transposable element family is variable, even within the same class of elements. In general, transcriptional activity of the <it>gypsy</it>-like retrotransposons is higher compared to other classes. Transcriptional activity of several transposable elements is specially high in shoot apical meristem and sperm cells. Sequence comparisons between genomic and transcribed sequences suggest that only a few copies are transcriptionally active.</p> <p>Conclusions</p> <p>The use of powerful high-throughput sequencing methodologies allowed us to elucidate the extent and character of repetitive element transcription in maize cells. The finding that some families of transposable elements have a considerable transcriptional activity in some tissues suggests that, either transposition is more frequent than previously expected, or cells can control transposition at a post-transcriptional level.</p

    Suppression of Allograft Rejection by Tim-1-Fc through Cross-Linking with a Novel Tim-1 Binding Partner on T Cells

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    Engagement of T-cell immunoglobulin mucin (Tim)-1 on T cells with its ligand, Tim-4, on antigen presenting cells delivers positive costimulatory signals to T cells. However, the molecular mechanisms for Tim-1-mediated regulation of T-cell activation and differentiation are relatively poorly understood. Here we investigated the role of Tim-1 in T-cell responses and allograft rejection using recombinant human Tim-1 extracellular domain and IgG1-Fc fusion proteins (Tim-1-Fc). In vitro assays confirmed that Tim-1-Fc selectively binds to CD4+ effector T cells, but not dendritic cells or natural regulatory T cells (nTregs). Tim-1-Fc was able to inhibit the responses of purified CD4+ T cells that do not express Tim-4 to stimulation by anti-CD3/CD28 mAbs, and this inhibition was associated with reduced AKT and ERK1/2 phosphorylation, but it had no influence on nTregs. Moreover, Tim-1-Fc inhibited the proliferation of CD4+ T cells stimulated by allogeneic dendritic cells. Treatment of recipient mice with Tim-1-Fc significantly prolonged cardiac allograft survival in a fully MHC-mismatched strain combination, which was associated with impaired Th1 response and preserved Th2 and nTregs function. Importantly, the frequency of Foxp3+ cells in splenic CD4+ T cells was increased, thus shifting the balance toward regulators, even though Tim-1-Fc did not induce Foxp3 expression in CD4+CD25− T cells directly. These results indicate that Tim-1-Fc can inhibit T-cell responses through an unknown Tim-1 binding partner on T cells, and it is a promising immunosuppressive agent for preventing allograft rejection

    Prevention of Ocular Scarring Post Glaucoma Filtration Surgery Using the Inflammatory Cell and Platelet Binding Modulator Saratin in a Rabbit Model

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    Clinical Relevance: Late complications can occur with use of current antimetabolites to prevent scarring following glaucoma filtration surgery (GFS). Safer, more targeted, anti-fibrosis agents are sought. Objectives: The protein saratin has been shown to exhibit anti-fibrotic and anti-thrombotic properties in response to injury, but had not been used for glaucoma surgery. The goal of this study was to compare the efficacy of saratin with that of the widely accepted mitomycin-C (MMC) in prolonging bleb survival following GFS in the rabbit model. Two saratin delivery routes were compared; a single intraoperative topical application versus a combination of intraoperative topical application with two additional postoperative injections. Methods: Twenty-four New Zealand White rabbits underwent GFS and received either intraoperative topical saratin, intraoperative topical saratin plus two injections on post-operative days 4 and 8, balanced saline solution (BSS), or MMC. The bleb tissues and their elevation durations were compared based on clinical and histological findings. Results: Rabbits receiving topical+injections of saratin had a mean bleb survival of 33.668.5 days, significantly higher than the negative BSS controls, which averaged 17.466.0 days (p = 0.018). No improvement over BSS was seen for rabbits receiving topical saratin only (15.564.8 days, p = 0.749). Rabbits receiving saratin did not develop bleb avascularity and thinning associated with MMC treatment and there were no apparent clinical signs of toxicity
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