1,893 research outputs found

    Beta defensin-2 is reduced in central but not in distal airways of smoker COPD patients

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    Background: Altered pulmonary defenses in chronic obstructive pulmonary disease (COPD) may promote distal airways bacterial colonization. The expression/activation of Toll Like receptors (TLR) and beta 2 defensin (HBD2) release by epithelial cells crucially affect pulmonary defence mechanisms. Methods: The epithelial expression of TLR4 and of HBD2 was assessed in surgical specimens from current smokers COPD (s-COPD; n = 17), ex-smokers COPD (ex-s-COPD; n = 8), smokers without COPD (S; n = 12), and from non-smoker non-COPD subjects (C; n = 13). Results: In distal airways, s-COPD highly expressed TLR4 and HBD2. In central airways, S and s-COPD showed increased TLR4 expression. Lower HBD2 expression was observed in central airways of s-COPD when compared to S and to ex-s-COPD. s-COPD had a reduced HBD2 gene expression as demonstrated by real-time PCR on micro-dissected bronchial epithelial cells. Furthermore, HBD2 expression positively correlated with FEV1/FVC ratio and inversely correlated with the cigarette smoke exposure. In a bronchial epithelial cell line (16 HBE) IL-1β significantly induced the HBD2 mRNA expression and cigarette smoke extracts significantly counteracted this IL-1 mediated effect reducing both the activation of NFkB pathway and the interaction between NFkB and HBD2 promoter. Conclusions: This study provides new insights on the possible mechanisms involved in the alteration of innate immunity mechanisms in COPD. © 2012 Pace et al

    Pathological and ecological host consequences of infection by an introduced fish parasite

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    The infection consequences of the introduced cestode fish parasite Bothriocephalus acheilognathi were studied in a cohort of wild, young-of-the-year common carp Cyprinus carpio that lacked co-evolution with the parasite. Within the cohort, parasite prevalence was 42% and parasite burdens were up to 12% body weight. Pathological changes within the intestinal tract of parasitized carp included distension of the gut wall, epithelial compression and degeneration, pressure necrosis and varied inflammatory changes. These were most pronounced in regions containing the largest proportion of mature proglottids. Although the body lengths of parasitized and non-parasitized fish were not significantly different, parasitized fish were of lower body condition and reduced weight compared to non-parasitized conspecifics. Stable isotope analysis (δ15N and δ13C) revealed trophic impacts associated with infection, particularly for δ15N where values for parasitized fish were significantly reduced as their parasite burden increased. In a controlled aquarium environment where the fish were fed ad libitum on an identical food source, there was no significant difference in values of δ15N and δ13C between parasitized and non-parasitized fish. The growth consequences remained, however, with parasitized fish growing significantly slower than non-parasitized fish, with their feeding rate (items s−1) also significantly lower. Thus, infection by an introduced parasite had multiple pathological, ecological and trophic impacts on a host with no experience of the parasite

    Leaf segmentation in plant phenotyping: a collation study

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    Image-based plant phenotyping is a growing application area of computer vision in agriculture. A key task is the segmentation of all individual leaves in images. Here we focus on the most common rosette model plants, Arabidopsis and young tobacco. Although leaves do share appearance and shape characteristics, the presence of occlusions and variability in leaf shape and pose, as well as imaging conditions, render this problem challenging. The aim of this paper is to compare several leaf segmentation solutions on a unique and first-of-its-kind dataset containing images from typical phenotyping experiments. In particular, we report and discuss methods and findings of a collection of submissions for the first Leaf Segmentation Challenge of the Computer Vision Problems in Plant Phenotyping workshop in 2014. Four methods are presented: three segment leaves by processing the distance transform in an unsupervised fashion, and the other via optimal template selection and Chamfer matching. Overall, we find that although separating plant from background can be accomplished with satisfactory accuracy (>>90 % Dice score), individual leaf segmentation and counting remain challenging when leaves overlap. Additionally, accuracy is lower for younger leaves. We find also that variability in datasets does affect outcomes. Our findings motivate further investigations and development of specialized algorithms for this particular application, and that challenges of this form are ideally suited for advancing the state of the art. Data are publicly available (online at http://​www.​plant-phenotyping.​org/​datasets) to support future challenges beyond segmentation within this application domain

    External validation of the preoperative Karakiewicz nomogram in a large multicentre series of patients with renal cell carcinoma

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    To perform a formal external validation of the preoperative Karakiewicz nomogram (KN) for the prediction of cancer-specific survival (CSS) using a large series of surgically treated patients diagnosed with organ-confined or metastatic renal cell carcinoma (RCC).Patient population originated from a series of retrospectively gathered cases that underwent radical or partial nephrectomy between years 1995 and 2007 for suspicion of kidney cancer. The original Cox coefficients were used to generate the predicted risk of CSS at 1, 2, 5, and 10 years following surgery and compared to the observed risk of CSS in the current population. External validation was quantified using measures of predictive accuracy, defined as model discrimination and calibration.A total of 3,374 patients were identified. Relative to the original development cohort, the current sample population had a larger proportion of patients with localized (40.0 vs. 26.3 \%, P < 0.001) and non-metastatic (92.2 vs. 88.1 \%, P = 0.03) disease at presentation. Model discrimination for the prediction of CSS was 87.8 \% (95 \% CI, 84.4-91.4) at 1 year, 87.0 \% (95 \% CI, 84.4-89.5) at 2 years, 84.7 \% (95 \% CI, 82.3-87.1) at 5 years, and 85.9 \% (95 \% CI, 83.2-88.6) at 10 years. The relationship between predicted and observed CSS risk was adequate in the calibration plot.The use of the KN for the prediction of CSS in patients diagnosed with renal cell carcinoma was validated in the current study. In consequence, this tool may be recommended for routine clinical counseling in patients with various stages of RCC in the preoperative setting

    Evidence of the physical interaction between rpl22 and the transposable element doc5, a heterochromatic transposon of drosophila melanogaster

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    Chromatin is a highly dynamic biological entity that allows for both the control of gene expression and the stabilization of chromosomal domains. Given the high degree of plasticity observed in model and non-model organisms, it is not surprising that new chromatin components are frequently described. In this work, we tested the hypothesis that the remnants of the Doc5 transpos-able element, which retains a heterochromatin insertion pattern in the melanogaster species complex, can be bound by chromatin proteins, and thus be involved in the organization of heterochromatic domains. Using the Yeast One Hybrid approach, we found Rpl22 as a potential interacting protein of Doc5. We further tested in vitro the observed interaction through Electrophoretic Mobility Shift Assay, uncovering that the N-terminal portion of the protein is sufficient to interact with Doc5. However, in situ localization of the native protein failed to detect Rpl22 association with chromatin. The results obtained are discussed in the light of the current knowledge on the extra-ribosomal role of ribosomal protein in eukaryotes, which suggests a possible role of Rpl22 in the determination of the heterochromatin in Drosophila
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