355 research outputs found
Deep Learning from Dual-Energy Information for Whole-Heart Segmentation in Dual-Energy and Single-Energy Non-Contrast-Enhanced Cardiac CT
Deep learning-based whole-heart segmentation in coronary CT angiography
(CCTA) allows the extraction of quantitative imaging measures for
cardiovascular risk prediction. Automatic extraction of these measures in
patients undergoing only non-contrast-enhanced CT (NCCT) scanning would be
valuable. In this work, we leverage information provided by a dual-layer
detector CT scanner to obtain a reference standard in virtual non-contrast
(VNC) CT images mimicking NCCT images, and train a 3D convolutional neural
network (CNN) for the segmentation of VNC as well as NCCT images.
Contrast-enhanced acquisitions on a dual-layer detector CT scanner were
reconstructed into a CCTA and a perfectly aligned VNC image. In each CCTA
image, manual reference segmentations of the left ventricular (LV) myocardium,
LV cavity, right ventricle, left atrium, right atrium, ascending aorta, and
pulmonary artery trunk were obtained and propagated to the corresponding VNC
image. These VNC images and reference segmentations were used to train 3D CNNs
for automatic segmentation in either VNC images or NCCT images. Automatic
segmentations in VNC images showed good agreement with reference segmentations,
with an average Dice similarity coefficient of 0.897 \pm 0.034 and an average
symmetric surface distance of 1.42 \pm 0.45 mm. Volume differences [95%
confidence interval] between automatic NCCT and reference CCTA segmentations
were -19 [-67; 30] mL for LV myocardium, -25 [-78; 29] mL for LV cavity, -29
[-73; 14] mL for right ventricle, -20 [-62; 21] mL for left atrium, and -19
[-73; 34] mL for right atrium, respectively. In 214 (74%) NCCT images from an
independent multi-vendor multi-center set, two observers agreed that the
automatic segmentation was mostly accurate or better. This method might enable
quantification of additional cardiac measures from NCCT images for improved
cardiovascular risk prediction
Anthropogenic Impacts on Aquatic Insects in Six Streams of South Western Ghats
Diversity patterns of aquatic insects among sampling sites lying with!ç the unprotected and protected areas of Western Ghats were studied. This study primarily emphasizes whether anthropogenic influence is the prime cause for the presence of aquatic insects especialIy of pollution-sensitive organisms belonging to the orders Ephemeroptera, Plecoptera and Trichoptera, or to factors such as the physico-chemical features of the water, or sampling methods. Six streams were sampled quantitatively, of which three streams (Abbifalls, Monkey falls and SiIver Cascade) were within protected areas and the remaining three streams (Kumbakarai, Shenbagadevi and Manimutharu falls) were in unprotected areas. A total of 3,209 individual aquatic insects belonging to 25 genera, 18 families and 7 orders were collected. The highest species richness and abundance was observed in Monkey falls followed by Kumbakkarai falls. Large çumbers of more habitat-sensitive organisms such as Ecdyonurus sp., Epeorus sp., Thalerosphyrus sp., Euthraulus sp., and Nathanella sp., were found in Monkey falls. Though the species assemblage was somewhat different, pollution-sensitive taxa were also observed in Kumbakkarai falls. Shenbagadevi and Manimutharu falls had a lower diversity of aquatic insects. The likely causes of these differences are discussed
Vascular adhesion protein-1 is elevated in primary sclerosing cholangitis, is predictive of clinical outcome and facilitates recruitment of gut-tropic lymphocytes to liver in a substrate-dependent manner
OBJECTIVE: Primary
sclerosing cholangitis (PSC) is the classical hepatobiliary
manifestation of IBD. This clinical association is linked pathologically
to the recruitment of mucosal T cells to the liver, via vascular
adhesion protein (VAP)-1-dependent enzyme activity. Our aim was to
examine the expression, function and enzymatic activation of the
ectoenzyme VAP-1 in patients with PSC.DESIGN: We
examined VAP-1 expression in patients with PSC, correlated levels with
clinical characteristics and determined the functional consequences of
enzyme activation by specific enzyme substrates on hepatic endothelium.RESULTS: The
intrahepatic enzyme activity of VAP-1 was elevated in PSC versus
immune-mediated disease controls and non-diseased liver (p<0.001).
The adhesion of gut-tropic α4β7+lymphocytes to hepatic
endothelial cells in vitro under flow was attenuated by 50% following
administration of the VAP-1 inhibitor semicarbazide (p<0.01). Of a
number of natural VAP-1 substrates tested, cysteamine-which can be
secreted by inflamed colonic epithelium and gut bacteria-was the most
efficient (yielded the highest enzymatic rate) and efficacious in its
ability to induce expression of functional mucosal addressin cell
adhesion molecule-1 on hepatic endothelium. In a prospectively evaluated
patient cohort with PSC, elevated serum soluble (s)VAP-1 levels
predicted poorer transplant-free survival for patients, independently
(HR: 3.85, p=0.003) and additively (HR: 2.02, p=0.012) of the presence
of liver cirrhosis.CONCLUSIONS: VAP-1
expression is increased in PSC, facilitates adhesion of gut-tropic
lymphocytes to liver endothelium in a substrate-dependent manner, and
elevated levels of its circulating form predict clinical outcome in
patients.</p
@THEVIEWER: Analyzing the offline and online impact of a dedicated conversation manager in the newsroom of a public broadcaster
This study is built around the appointment of a dedicated “conversation manager” at the Flemish public broadcaster VRT. We focus on (1) the impact of the conversation manager on Twitter activity of the viewers and (2) the impact of the tweeting audience in the newsroom. Our framework combines journalistic as well as social media logics in Bourdieu’s field framework, for which we combine Twitter data and newsroom inquiry. The network analysis of Twitter activity shows the impact of the conversation manager, although his activities are primarily guided by traditional journalistic values. In turn, the tweeting audience impacts newsroom practices, predominantly as an indicator of audience appreciation. To conclude, social media data further complicate the definition and understanding of “the public.
The impact of Stieltjes' work on continued fractions and orthogonal polynomials
Stieltjes' work on continued fractions and the orthogonal polynomials related
to continued fraction expansions is summarized and an attempt is made to
describe the influence of Stieltjes' ideas and work in research done after his
death, with an emphasis on the theory of orthogonal polynomials
Burden of childhood-onset arthritis
Juvenile arthritis comprises a variety of chronic inflammatory diseases causing erosive arthritis in children, often progressing to disability. These children experience functional impairment due to joint and back pain, heel pain, swelling of joints and morning stiffness, contractures, pain, and anterior uveitis leading to blindness. As children who have juvenile arthritis reach adulthood, they face possible continuing disease activity, medication-associated morbidity, and life-long disability and risk for emotional and social dysfunction. In this article we will review the burden of juvenile arthritis for the patient and society and focus on the following areas: patient disability; visual outcome; other medical complications; physical activity; impact on HRQOL; emotional impact; pain and coping; ambulatory visits, hospitalizations and mortality; economic impact; burden on caregivers; transition issues; educational occupational outcomes, and sexuality
Altered T Cell Memory and Effector Cell Development in Chronic Lymphatic Filarial Infection That Is Independent of Persistent Parasite Antigen
Chronic lymphatic filarial (LF) infection is associated with suppression of parasite-specific T cell responses that persist even following elimination of infection. While several mechanisms have been implicated in mediating this T cell specific downregulation, a role for alterations in the homeostasis of T effector and memory cell populations has not been explored. Using multiparameter flow cytometry, we investigated the role of persistent filarial infection on the maintenance of T cell memory in patients from the filarial-endemic Cook Islands. Compared to filarial-uninfected endemic normals (EN), microfilaria (mf) positive infected patients (Inf) had a reduced CD4 central memory (TCM) compartment. In addition, Inf patients tended to have more effector memory cells (TEM) and fewer effector cells (TEFF) than did ENs giving significantly smaller TEFF ∶ TEM ratios. These contracted TCM and TEFF populations were still evident in patients previously mf+ who had cleared their infection (CLInf). Moreover, the density of IL-7Rα, necessary for T memory cell maintenance (but decreased in T effector cells), was significantly higher on memory cells of Inf and CLInf patients, although there was no evidence for decreased IL-7 or increased soluble IL7-Rα, both possible mechanisms for signaling defects in memory cells. However, effector cells that were present in Inf and CLInf patients had lower percentages of HLA-DR suggesting impaired function. These changes in T cell populations appear to reflect chronicity of infection, as filarial-infected children, despite the presence of active infection, did not show alterations in the frequencies of these T cell phenotypes. These data indicate that filarial-infected patients have contracted TCM compartments and a defect in effector cell development, defects that persist even following clearance of infection. The fact that these global changes in memory and effector cell compartments do not yet occur in infected children makes early treatment of LF even more crucial
Mixed Th1 and Th2 Mycobacterium tuberculosis-specific CD4 T cell responses in patients with active pulmonary tuberculosis from Tanzania.
Mycobacterium tuberculosis (Mtb) and helminth infections elicit antagonistic immune effector functions and are co-endemic in several regions of the world. We therefore hypothesized that helminth infection may influence Mtb-specific T-cell immune responses. We evaluated the cytokine profile of Mtb-specific T cells in 72 individuals with pulmonary TB disease recruited from two Sub-Saharan regions with high and moderate helminth burden i.e. 55 from Tanzania (TZ) and 17 from South Africa (SA), respectively. We showed that Mtb-specific CD4 T-cell functional profile of TB patients from Tanzania are primarily composed of polyfunctional Th1 and Th2 cells, associated with increased expression of Gata-3 and reduced expression of T-bet in memory CD4 T cells. In contrast, the cytokine profile of Mtb-specific CD4 T cells of TB patients from SA was dominated by single IFN-γ and dual IFN-γ/TNF-α and associated with TB-induced systemic inflammation and elevated serum levels of type I IFNs. Of note, the proportion of patients with Mtb-specific CD8 T cells was significantly reduced in Mtb/helminth co-infected patients from TZ. It is likely that the underlying helminth infection and possibly genetic and other unknown environmental factors may have caused the induction of mixed Th1/Th2 Mtb-specific CD4 T cell responses in patients from TZ. Taken together, these results indicate that the generation of Mtb-specific CD4 and CD8 T cell responses may be substantially influenced by environmental factors in vivo. These observations may have major impact in the identification of immune biomarkers of disease status and correlates of protection
Orai3 Surface Accumulation and Calcium Entry Evoked by Vascular Endothelial Growth Factor
Objective: Vascular endothelial growth factor (VEGF) acts, in part, by triggering calcium ion (Ca2+) entry. Here, we sought understanding of a Synta66-resistant Ca2+ entry pathway activated by VEGF. Approach and Results: Measurement of intracellular Ca2+ in human umbilical vein endothelial cells detected a Synta66-resistant component of VEGF-activated Ca2+ entry that occurred within 2 minutes after VEGF exposure. Knockdown of the channel-forming protein Orai3 suppressed this Ca2+ entry. Similar effects occurred in 3 further types of human endothelial cell. Orai3 knockdown was inhibitory for VEGF-dependent endothelial tube formation in Matrigel in vitro and in vivo in the mouse. Unexpectedly, immunofluorescence and biotinylation experiments showed that Orai3 was not at the surface membrane unless VEGF was applied, after which it accumulated in the membrane within 2 minutes. The signaling pathway coupling VEGF to the effect on Orai3 involved activation of phospholipase Cγ1, Ca2+ release, cytosolic group IV phospholipase A2α, arachidonic acid production, and, in part, microsomal glutathione S-transferase 2, an enzyme which catalyses the formation of leukotriene C4 from arachidonic acid. Shear stress reduced microsomal glutathione S-transferase 2 expression while inducing expression of leukotriene C4 synthase, suggesting reciprocal regulation of leukotriene C4–synthesizing enzymes and greater role of microsomal glutathione S-transferase 2 in low shear stress. Conclusions: VEGF signaling via arachidonic acid and arachidonic acid metabolism causes Orai3 to accumulate at the cell surface to mediate Ca2+ entry and downstream endothelial cell remodeling
Understanding the implementation and effectiveness of a group-based early parenting intervention : a process evaluation protocol
BACKGROUND: Group-based early parenting interventions delivered through community-based services may be a potentially effective means of promoting infant and family health and wellbeing. Process evaluations of these complex interventions provide vital information on how they work, as well as the conditions which shape and influence outcomes. This information is critical to decision makers and service providers who wish to embed prevention and early interventions in usual care settings. In this paper, a process evaluation protocol for an early years parenting intervention, the Parent and Infant (PIN) program, is described. This program combines a range of developmentally-appropriate supports, delivered in a single intervention process, for parents and infants (0–2 years) and aimed at enhancing parental competence, strengthening parent-infant relationships and improving infant wellbeing and adjustment. METHODS: The process evaluation is embedded within a controlled trial and accompanying cost-effectiveness evaluation. Building from extant frameworks and evaluation methods, this paper presents a systematic approach to the process evaluation of the PIN program and its underlying change principles, the implementation of the program, the context of implementation and the change mechanisms which influence and shape parent and infant outcomes. We will use a multi-method strategy, including semi-structured interviews and group discussions with key stakeholders, documentary analysis and survey methodology. DISCUSSION: The integration of innovations into existing early years systems and services is a challenging multifaceted undertaking. This process evaluation will make an important contribution to knowledge about the implementation of such programs, while also providing an example of how theory-based research can be embedded within the evaluation of community-based interventions. We discuss the strengths of the research, such as the adoption of a collaborative approach to data collection, while we also identify potential challenges, including capturing and assessing complex aspects of the intervention. TRIAL REGISTRATION: ISRCTN17488830 (Date of registration: 27/11/15). This trial was retrospectively registered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12913-016-1737-3) contains supplementary material, which is available to authorized users
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