260 research outputs found
Double-Stranded RNA Attenuates the Barrier Function of Human Pulmonary Artery Endothelial Cells
Circulating RNA may result from excessive cell damage or acute viral infection and can interact with vascular endothelial cells. Despite the obvious clinical implications associated with the presence of circulating RNA, its pathological effects on endothelial cells and the governing molecular mechanisms are still not fully elucidated. We analyzed the effects of double stranded RNA on primary human pulmonary artery endothelial cells (hPAECs). The effect of natural and synthetic double-stranded RNA (dsRNA) on hPAECs was investigated using trans-endothelial electric resistance, molecule trafficking, calcium (Ca2+) homeostasis, gene expression and proliferation studies. Furthermore, the morphology and mechanical changes of the cells caused by synthetic dsRNA was followed by in-situ atomic force microscopy, by vascular-endothelial cadherin and F-actin staining. Our results indicated that exposure of hPAECs to synthetic dsRNA led to functional deficits. This was reflected by morphological and mechanical changes and an increase in the permeability of the endothelial monolayer. hPAECs treated with synthetic dsRNA accumulated in the G1 phase of the cell cycle. Additionally, the proliferation rate of the cells in the presence of synthetic dsRNA was significantly decreased. Furthermore, we found that natural and synthetic dsRNA modulated Ca2+ signaling in hPAECs by inhibiting the sarco-endoplasmic Ca2+-ATPase (SERCA) which is involved in the regulation of the intracellular Ca2+ homeostasis and thus cell growth. Even upon synthetic dsRNA stimulation silencing of SERCA3 preserved the endothelial monolayer integrity. Our data identify novel mechanisms by which dsRNA can disrupt endothelial barrier function and these may be relevant in inflammatory processes
Phenotypic redshifts with self-organizing maps: A novel method to characterize redshift distributions of source galaxies for weak lensing
Wide-field imaging surveys such as the Dark Energy Survey (DES) rely on
coarse measurements of spectral energy distributions in a few filters to
estimate the redshift distribution of source galaxies. In this regime, sample
variance, shot noise, and selection effects limit the attainable accuracy of
redshift calibration and thus of cosmological constraints. We present a new
method to combine wide-field, few-filter measurements with catalogs from deep
fields with additional filters and sufficiently low photometric noise to break
degeneracies in photometric redshifts. The multi-band deep field is used as an
intermediary between wide-field observations and accurate redshifts, greatly
reducing sample variance, shot noise, and selection effects. Our implementation
of the method uses self-organizing maps to group galaxies into phenotypes based
on their observed fluxes, and is tested using a mock DES catalog created from
N-body simulations. It yields a typical uncertainty on the mean redshift in
each of five tomographic bins for an idealized simulation of the DES Year 3
weak-lensing tomographic analysis of , which is a
60% improvement compared to the Year 1 analysis. Although the implementation of
the method is tailored to DES, its formalism can be applied to other large
photometric surveys with a similar observing strategy.Comment: 24 pages, 11 figures; matches version accepted to MNRA
Room temperature chiral magnetic skyrmion in ultrathin magnetic nanostructures
Magnetic skyrmions are chiral spin structures with a whirling configuration.
Their topological properties, nanometer size and the fact that they can be
moved by small current densities have opened a new paradigm for the
manipulation of magnetisation at the nanoscale. To date, chiral skyrmion
structures have been experimentally demonstrated only in bulk materials and in
epitaxial ultrathin films and under external magnetic field or at low
temperature. Here, we report on the observation of stable skyrmions in
sputtered ultrathin Pt/Co/MgO nanostructures, at room temperature and zero
applied magnetic field. We use high lateral resolution X-ray magnetic circular
dichroism microscopy to image their chiral N\'eel internal structure which we
explain as due to the large strength of the Dzyaloshinskii-Moriya interaction
as revealed by spin wave spectroscopy measurements. Our results are
substantiated by micromagnetic simulations and numerical models, which allow
the identification of the physical mechanisms governing the size and stability
of the skyrmions.Comment: Submitted version. Extended version to appear in Nature
Nanotechnolog
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Rapid progression of prostate cancer in men with a BRCA2 mutation.
Men with BRCA2 mutations have been found to be at increased risk of developing prostate cancer. There is a recent report that BRCA2 carriers with prostate cancer have poorer survival than noncarrier prostate cancer patients. In this study, we compared survival of men with a BRCA2 mutation and prostate cancer with that of men with a BRCA1 mutation and prostate cancer. We obtained the age at diagnosis, age at death or current age from 182 men with prostate cancer from families with a BRCA2 mutation and from 119 men with prostate cancer from families with a BRCA1 mutation. The median survival from diagnosis was 4.0 years for men with a BRCA2 mutation vs 8.0 years for men with a BRCA1 mutation, and the difference was highly significant (P<0.01). It may be important to develop targeted chemotherapies to treat prostate cancer in men with a BRCA2 mutation
NS1 Specific CD8(+) T-Cells with Effector Function and TRBV11 Dominance in a Patient with Parvovirus B19 Associated Inflammatory Cardiomyopathy
Background: Parvovirus B19 (B19V) is the most commonly detected virus in endomyocardial biopsies (EMBs) from patients with inflammatory cardiomyopathy (DCMi). Despite the importance of T-cells in antiviral defense, little is known about the role of B19V specific T-cells in this entity.
Methodology and Principal Findings: An exceptionally high B19V viral load in EMBs (115,091 viral copies/mg nucleic acids), peripheral blood mononuclear cells (PBMCs) and serum was measured in a DCMi patient at initial presentation, suggesting B19V viremia. The B19V viral load in EMBs had decreased substantially 6 and 12 months afterwards, and was not traceable in PBMCs and the serum at these times. Using pools of overlapping peptides spanning the whole B19V proteome, strong CD8(+) T-cell responses were elicited to the 10-amico-acid peptides SALKLAIYKA (19.7% of all CD8(+) cells) and QSALKLAIYK (10%) and additional weaker responses to GLCPHCINVG (0.71%) and LLHTDFEQVM (0.06%). Real-time RT-PCR of IFN gamma secretion-assay-enriched T-cells responding to the peptides, SALKLAIYKA and GLCPHCINVG, revealed a disproportionately high T-cell receptor Vbeta (TRBV) 11 expression in this population. Furthermore, dominant expression of type-1 (IFN gamma, IL2, IL27 and Tbet) and of cytotoxic T-cell markers (Perforin and Granzyme B) was found, whereas gene expression indicating type-2 (IL4, GATA3) and regulatory T-cells (FoxP3) was low.
Conclusions: Our results indicate that B19V Ag-specific CD8(+) T-cells with effector function are involved in B19V associated DCMi. In particular, a dominant role of TRBV11 and type-1/CTL effector cells in the T-cell mediated antiviral immune response is suggested. The persistence of B19V in the endomyocardium is a likely antigen source for the maintenance of CD8(+) T-cell responses to the identified epitopes
Anti-müllerian hormone is not associated with cardiometabolic risk factors in adolescent females
<p>Objectives: Epidemiological evidence for associations of Anti-Müllerian hormone (AMH) with cardiometabolic risk factors is lacking. Existing evidence comes from small studies in select adult populations, and findings are conflicting. We aimed to assess whether AMH is associated with cardiometabolic risk factors in a general population of adolescent females.</p>
<p>Methods: AMH, fasting insulin, glucose, HDLc, LDLc, triglycerides and C-reactive protein (CRP) were measured at a mean age 15.5 years in 1,308 female participants in the Avon Longitudinal Study of Parents and Children (ALSPAC). Multivariable linear regression was used to examine associations of AMH with these cardiometabolic outcomes.</p>
<p>Results: AMH values ranged from 0.16–35.84 ng/ml and median AMH was 3.57 ng/ml (IQR: 2.41, 5.49). For females classified as post-pubertal (n = 848) at the time of assessment median (IQR) AMH was 3.81 ng/ml (2.55, 5.82) compared with 3.25 ng/ml (2.23, 5.05) in those classed as early pubertal (n = 460, P≤0.001). After adjusting for birth weight, gestational age, pubertal stage, age, ethnicity, socioeconomic position, adiposity and use of hormonal contraceptives, there were no associations with any of the cardiometabolic outcomes. For example fasting insulin changed by 0% per doubling of AMH (95%CI: −3%,+2%) p = 0.70, with identical results if HOMA-IR was used. Results were similar after additional adjustment for smoking, physical activity and age at menarche, after exclusion of 3% of females with the highest AMH values, after excluding those that had not started menarche and after excluding those using hormonal contraceptives.</p>
<p>Conclusion: Our results suggest that in healthy adolescent females, AMH is not associated with cardiometabolic risk factors.</p>
Use of antibiotic spacers for knee endoprosthesis infections treatment
OBJCTIVE: The aim of this study is to evaluate the use of cement spacers impregnated with antibiotics for the treatment of infections in the nonconventional endoprostheses of the knee. METHODOLOGY: We have treated seven patients since 2004 (of which six were submitted to surgery in our service and one patient had been submitted to a primary tumor surgery in another removal service) with deep infection in knee tumor prosthesis. All patients were submitted to endoprosthesis removal and reconstructed with antibiotic cement spacer. All patients were monitored both clinically and by lab tests as for monitoring the evolution, being considered able for reviews after 6 (six) months without infections signs. RESULTS: We have noted a small predominance of infectious processes on the prosthesis inserted on proximal tibia as compared with distal femur (57.1% x 42.9%). The mean follow-up time of patients was 68.2 months. During the follow up, one patient died as a result of the root disease. Six patients out of seven were regarded as cured and one persisted with infection signs and symptoms. CONCLUSION: The results obtained up to date have motivated us to continue using this method of treatment.OBJETIVO: O objetivo do estudo é avaliar a utilização dos espaçadores de cimento acrílico com antibiótico no tratamento das infecções em endopróteses não convencionais de joelho. MÉTODO: Desde de 2004 foram tratados sete pacientes (seis pacientes operados no nosso serviço e um paciente que havia sido submetido a cirurgia primária do tumor em outro serviço) com infecção peri-endoprótese não convencional de joelho. Todos pacientes foram submetidos a retirada da endoprótese e reconstrução com espaçador com cimento acrílico com antibiótico. Todos os pacientes foram monitorados clínica e laboratorialmente quanto ao controle da evolução, sendo considerados aptos para a revisão e recolocação de endoprótese após 06 (seis) meses sem sinais infecciosos RESULTADOS: Notamos um discreto predomínio do do processo infeccioso nas próteses realizadas na tíbia proximal em comparação com o fêmur distal (57,1% x 42,9%). O seguimento médio dos pacientes foi 68,2 meses. Durante o seguimento, um paciente faleceu devido a doença de base. Dos sete pacientes, 6 foram considerados curados e um persistiu com sinais e sintomas de infecção. CONCLUSÃO: Os resultados obtidos até o momento tem motivado a continuidade deste método de tratamento.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de Ortopedia e TraumatologiaUNIFESP, EPM, Depto. de Ortopedia e TraumatologiaSciEL
A comparison of Power Doppler with conventional sonographic imaging for the evaluation of renal artery stenosis
Percutaneous coronary intervention can be associated with distal embolization of thrombotic material causing myocardial necrosis and infarction. We discuss the role of intravascular imaging to guide the use of a distal protection device by describing the outcome of a young woman presenting with non-ST elevation myocardial infarction. Coronary angiography demonstrated an isolated minor stenosis in the proximal left anterior descending coronary artery with slight haziness beyond the lesion. Intravascular ultrasound confirmed an extensive thrombus overlying a bulky atherosclerotic plaque. A distal filter wire was therefore successfully used to reduce the risk of distal embolization. The use of intravascular ultrasound in patients presenting with acute coronary syndrome may reveal large thrombi that are difficult to image using conventional angiographic techniques. Intravascular ultrasound can therefore be used as a tool to select lesions requiring distal protection
On the relative bias of void tracers in the Dark Energy Survey
Luminous tracers of large-scale structure are not entirely representative of the distribution of mass in our Universe. As they arise from the highest peaks in the matter density field, the spatial distribution of luminous objects is biased towards those peaks. On large scales, where density fluctuations are mild, this bias simply amounts to a constant offset in the clustering amplitude of the tracer, known as linear bias. In this work we focus on the relative bias between galaxies and galaxy clusters that are located inside and in the vicinity of cosmic voids, extended regions of relatively low density in the large-scale structure of the Universe. With the help of mock data we verify that the relation between galaxy and cluster overdensity around voids remains linear. Hence, the void-centric density profiles of different tracers can be linked by a single multiplicative constant. This amounts to the same value as the relative linear bias between tracers for the largest voids in the sample. For voids of small sizes, which typically arise in higher density regions, this constant has a higher value, possibly showing an environmental dependence similar to that observed for the linear bias itself. We confirm our findings by analysing data obtained during the first year of observations by the Dark Energy Survey. As a side product, we present the first catalogue of three-dimensional voids extracted from a photometric survey with a controlled photo-z uncertainty. Our results will be relevant in forthcoming analyses that attempt to use voids as cosmological probes
Dark energy survey year 1 results: detection of intracluster light at redshift ∼ 0.25
International audienceUsing data collected by the Dark Energy Survey (DES), we report the detection of intracluster light (ICL) with ∼300 galaxy clusters in the redshift range of 0.2–0.3. We design methods to mask detected galaxies and stars in the images and stack the cluster light profiles, while accounting for several systematic effects (sky subtraction, instrumental point-spread function, cluster selection effects, and residual light in the ICL raw detection from background and cluster galaxies). The methods allow us to acquire high signal-to-noise measurements of the ICL and central galaxies (CGs), which we separate with radial cuts. The ICL appears as faint and diffuse light extending to at least 1 Mpc from the cluster center, reaching a surface brightness level of 30 mag arcsec−2. The ICL and the cluster CG contribute 44% ± 17% of the total cluster stellar luminosity within 1 Mpc. The ICL color is overall consistent with that of the cluster red sequence galaxies, but displays the trend of becoming bluer with increasing radius. The ICL demonstrates an interesting self-similarity feature—for clusters in different richness ranges, their ICL radial profiles are similar after scaling with cluster R 200m , and the ICL brightness appears to be a good tracer of the cluster radial mass distribution. These analyses are based on the DES redMaPPer cluster sample identified in the first year of observations
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