1,016 research outputs found
Suzaku observations of X-ray excess emission in the cluster of galaxies A3112
We analysed the Suzaku XIS1 data of the A3112 cluster of galaxies in order to
examine the X-ray excess emission in this cluster reported earlier with the
XMM-Newton and Chandra satellites. The best-fit temperature of the intracluster
gas depends strongly on the choice of the energy band used for the spectral
analysis. This proves the existence of excess emission component in addition to
the single-temperature MEKAL in A3112. We showed that this effect is not an
artifact due to uncertainties of the background modeling, instrument
calibration or the amount of Galactic absorption. Neither does the PSF scatter
of the emission from the cool core nor the projection of the cool gas in the
cluster outskirts produce the effect. Finally we modeled the excess emission
either by using an additional MEKAL or powerlaw component. Due to the small
differencies between thermal and non-thermal model we can not rule out the
non-thermal origin of the excess emission based on the goodness of the fit.
Assuming that it has a thermal origin, we further examined the Differential
Emission Measure (DEM) models. We utilised two different DEM models, a Gaussian
differential emission measure distribution (GDEM) and WDEM model, where the
emission measure of a number of thermal components is distributed as a
truncated power law. The best-fit XIS1 MEKAL temperature for the 0.4-7.0 keV
band is 4.7+-0.1 keV, consistent with that obtained using GDEM and WDEM models.Comment: 8 pages, 10 figures, accepted to A&
Androgen receptor-dependent and -independent mechanisms driving prostate cancer progression: Opportunities for therapeutic targeting from multiple angles.
Despite aggressive treatment for localized cancer, prostate cancer (PC) remains a leading cause of cancer-related death for American men due to a subset of patients progressing to lethal and incurable metastatic castrate-resistant prostate cancer (CRPC). Organ-confined PC is treated by surgery or radiation with or without androgen deprivation therapy (ADT), while options for locally advanced and disseminated PC include radiation combined with ADT, or systemic treatments including chemotherapy. Progression to CRPC results from failure of ADT, which targets the androgen receptor (AR) signaling axis and inhibits AR-driven proliferation and survival pathways. The exact mechanisms underlying the transition from androgen-dependent PC to CRPC remain incompletely understood. Reactivation of AR has been shown to occur in CRPC despite depletion of circulating androgens by ADT. At the same time, the presence of AR-negative cell populations in CRPC has also been identified. While AR signaling has been proposed as the primary driver of CRPC, AR-independent signaling pathways may represent additional mechanisms underlying CRPC progression. Identification of new therapeutic strategies to target both AR-positive and AR-negative PC cell populations and, thereby, AR-driven as well as non-AR-driven PC cell growth and survival mechanisms would provide a two-pronged approach to eliminate CRPC cells with potential for synthetic lethality. In this review, we provide an overview of AR-dependent and AR-independent molecular mechanisms which drive CRPC, with special emphasis on the role of the Jak2-Stat5a/b signaling pathway in promoting castrate-resistant growth of PC through both AR-dependent and AR-independent mechanisms
XMM-Newton and Chandra Cross Calibration Using HIFLUGCS Galaxy Clusters: Systematic Temperature Differences and Cosmological Impact
Cosmological constraints from clusters rely on accurate gravitational mass
estimates, which strongly depend on cluster gas temperature measurements.
Therefore, systematic calibration differences may result in biased,
instrument-dependent cosmological constraints. This is of special interest in
the light of the tension between the Planck results of the primary temperature
anisotropies of the CMB and Sunyaev-Zel'dovich plus X-ray cluster counts
analyses. We quantify in detail the systematics and uncertainties of the
cross-calibration of the effective area between five X-ray instruments,
EPIC-MOS1/MOS2/PN onboard XMM-Newton and ACIS-I/S onboard Chandra, and the
influence on temperature measurements. Furthermore, we assess the impact of the
cross calibration uncertainties on cosmology. Using the HIFLUGCS sample,
consisting of the 64 X-ray brightest galaxy clusters, we constrain the ICM
temperatures through spectral fitting in the same, mostly isothermal, regions
and compare them. Our work is an extension to a previous one using X-ray
clusters by the IACHEC. Performing spectral fitting in the full energy band we
find that best-fit temperatures determined with XMM-Newton/EPIC are
significantly lower than Chandra/ACIS temperatures. We demonstrate that effects
like multitemperature structure and different relative sensitivities of the
instruments at certain energy bands cannot explain the observed differences. We
conclude that using XMM-Newton/EPIC, instead of Chandra/ACIS to derive full
energy band temperature profiles for cluster mass determination results in an
8% shift towards lower OmegaM values and <1% shift towards higher sigma8 values
in a cosmological analysis of a complete sample of galaxy clusters. Such a
shift is insufficient to significantly alleviate the tension between Planck CMB
anisotropies and SZ plus XMM-Newton cosmological constraints.Comment: Accepted by A&A; Python-Script for modification of XMM-Newton/EPIC
and Chandra/ACIS effective areas according to the stacked residual ratios:
https://wikis.mit.edu/confluence/display/iachec/Data
Uptake of endocytic markers into mitotic yeast cells
Abstract[3H]α-Factor and Lucifer yellow were used to measure receptor mediated and fluid-phase endocytosis in the yeast Saccharomyces cerevisiae, arrested in mitosis by depolymerization of the microtubules or due to a mutation preventing nuclear division (cdc16. Both processes continued at roughly the same level as during interphase. This shows that in yeast endocytosis is not interrupted during mitosis like in mammalian cells
Exosome-mediated Transfer of αvβ3 Integrin from Tumorigenic to Nontumorigenic Cells Promotes a Migratory Phenotype.
The αvβ3 integrin is known to be highly upregulated during cancer progression and promotes a migratory and metastatic phenotype in many types of tumors. We hypothesized that the αvβ3 integrin is transferred through exosomes and, upon transfer, has the ability to support functional aberrations in recipient cells. Here, for the first time, it is demonstrated that αvβ3 is present in exosomes released from metastatic PC3 and CWR22Pc prostate cancer cells. Exosomal β3 is transferred as a protein from donor to nontumorigenic and tumorigenic cells as β3 protein or mRNA levels remain unaffected upon transcription or translation inhibition in recipient cells. Furthermore, it is shown that upon exosome uptake, de novo expression of an αvβ3 increases adhesion and migration of recipient cells on an αvβ3 ligand, vitronectin. To evaluate the relevance of these findings, exosomes were purified from the blood of TRAMP mice carrying tumors where the expression of αvβ3 is found higher than in exosomes from wild-type mice. In addition, it is demonstrated that αvβ3 is coexpressed with synaptophysin, a biomarker for aggressive neuroendocrine prostate cancer.
IMPLICATIONS: Overall this study reveals that the αvβ3 integrin is transferred from tumorigenic to nontumorigenic cells via exosomes, and its de novo expression in recipient cells promotes cell migration on its ligand. The increased expression of αvβ3 in exosomes from mice bearing tumors points to its clinical relevance and potential use as a biomarker. Mol Cancer Res; 14(11); 1136-46. ©2016 AACR
Adverse reactions from consumption of oral rabies vaccine baits in dogs in Finland
Background
Oral rabies vaccination of wildlife has effectively reduced the incidence of rabies in wildlife and has led to the elimination of rabies in large areas of Europe. The safety of oral rabies vaccines has been assessed in both target (red fox and raccoon dog) and several non-target species.
Case presentation
Since 2011, the competent authority in Finland has received a few reports of dogs experiencing adverse reactions that have been assumed to be caused by the consumption of baits containing oral rabies vaccine. The dogs usually exhibited gastrointestinal symptoms (vomiting, inappetence, constipation or diarrhoea) or behavioral symptoms (restlessness, listlessness and unwillingness to continue hunting).
Conclusions
Nevertheless, these adverse reactions are transient and non-life threatening. Even though the adverse reactions are unpleasant to individual dogs and their owners, the benefits of oral rabies vaccination clearly outweigh the risks
Effects of gnawing material, group size and cage level in rack on Wistar rats
Han: Wist rats were housed after weaning in groups of one, two, three or four in stainless steel cages with aspen chip bedding, with or without wooden gnawing blocks. The use of the blocks was assessed by Video recording and by measuringweight loss of the blocks. Behaviour of the males was tested in a five minute open field test. At the age of 14 weeks the males were transferred into cages with wire mesh bottom without contact bedding. After four weeks, the males were euthanized and weights of the adrenal glands, thymus and spleen were measured. The physiological and behavioural effects of blocks, group size and cage level in rack were tested. In solid bottom cages with direct bedding, the use of the blocks was minimal. It was not affected by the sex or age of the animals. Neither was it affected by the group size or the cage level in a rack. The gnawing of the blocks increased afier the rats were transferred on to grid floor without bedding. The food intake or weight gain were not affected by any of the factors studied. The presence of blocks decreased the adrenal weights in rats transferred into wire mesh cages. In open field, the animals living alone were less active and they moved slower from the peripheral to central area than the animals living in groups. The animals living on the highest shelf of the rack differed from the others in their latency times of rearing and grooming. None of the environmental variables tested affected the behavioural factor scores derived from factor analysis. In conclusion. the wooden blocks may reduce the stress of rats adapted to bedding, if they have to be removed to grid floor. The group size or cage level in rack influenced some behaviours of rats in the open field
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