137 research outputs found
Characterization of pentraxin 3 in the horse and its expression in airways
The long pentraxin 3 (PTX3) plays an important role in host defence and its over-expression may contribute to airway injury. The aim of the present study was therefore to characterize in more detail PTX3 and its expression in the horses’ airway. Six healthy horses and six horses affected by recurrent airway obstruction (R.A.O.) were submitted to a dusty environment challenge. PTX3 DNA and cDNA were cloned and sequenced. PTX3 expression was evaluated by RT-qPCR, Western blotting and immuno-histochemistry in bronchoalveolar lavage fluid (BALF) cells, BALF supernatant and bronchial epithelial cells. An alternative splicing of the second exon of PTX3 occurred, resulting in two forms of the protein: “spliced” (32 kDa) and “full length” (42 kDa). PTX3 was detected in BALF macrophages, neutrophils and bronchial epithelial cells. It was over-expressed in the BALF supernatant from R.A.O.-affected horses in crisis. However, dust was unable to induce PTX3 in BALF cells ex vivo, indicating that dust is an indirect inducer of PTX3. Dust exposure in-vivo induced PTX3 in BALF macrophages but there was no significant difference between healthy and R.A.O.-affected horses. Conversely, PTX3 was over-expressed in the bronchial epithelial cells from R.A.O.-affected horses in crisis. These data indicate a differential regulatory mechanism in inflammatory and bronchial epithelial cells and offer therapeutically interesting perspectives
WISDOM project - VI. Exploring the relation between supermassive black hole mass and galaxy rotation with molecular gas
Empirical correlations between the masses of supermassive black holes (SMBHs) and properties of their host galaxies are well-established. Among these is the correlation with the flat rotation velocity of each galaxy measured either at a large radius in its rotation curve or via a spatially-integrated emission line width. We propose here the use of the de-projected integrated CO emission line width as an alternative tracer of this rotation velocity, that has already been shown useful for the Tully-Fisher (luminosity-rotation velocity) relation. We investigate the correlation between CO line widths and SMBH masses for two samples of galaxies with dynamical SMBH mass measurements, with respectively spatially-resolved and unresolved CO observations. The tightest correlation is found using the resolved sample of 25 galaxies as log (MBH/M⊙) = (7.5 ± 0.1) + (8.5 ± 0.9)[log (W50/sin i km s−1) − 2.7], where MBH is the central SMBH mass, W50 the full-width at half-maximum of a double-horned emission line profile, and i the inclination of the CO disc. This relation has a total scatter of 0.6 dex, comparable to those of other SMBH mass correlations, and dominated by the intrinsic scatter of 0.5 dex. A tight correlation is also found between the de-projected CO line widths and the stellar velocity dispersions averaged within one effective radius. We apply our correlation to the COLD GASS sample to estimate the local SMBH mass function
The EGNoG Survey: Molecular Gas in Intermediate-Redshift Star-Forming Galaxies
We present the Evolution of molecular Gas in Normal Galaxies (EGNoG) survey,
an observational study of molecular gas in 31 star-forming galaxies from z=0.05
to z=0.5, with stellar masses of (4-30)x10^10 M_Sun and star formation rates of
4-100 M_Sun yr^-1. This survey probes a relatively un-observed redshift range
in which the molecular gas content of galaxies is expected to have evolved
significantly. To trace the molecular gas in the EGNoG galaxies, we observe the
CO(1-0) and CO(3-2) rotational lines using the Combined Array for Research in
Millimeter-wave Astronomy (CARMA). We detect 24 of 31 galaxies and present
resolved maps of 10 galaxies in the lower redshift portion of the survey. We
use a bimodal prescription for the CO to molecular gas conversion factor, based
on specific star formation rate, and compare the EGNoG galaxies to a large
sample of galaxies assembled from the literature. We find an average molecular
gas depletion time of 0.76 \pm 0.54 Gyr for normal galaxies and 0.06 \pm 0.04
Gyr for starburst galaxies. We calculate an average molecular gas fraction of
7-20% at the intermediate redshifts probed by the EGNoG survey. By expressing
the molecular gas fraction in terms of the specific star formation rate and
molecular gas depletion time (using typical values), we also calculate the
expected evolution of the molecular gas fraction with redshift. The predicted
behavior agrees well with the significant evolution observed from z~2.5 to
today.Comment: Accepted for publication in the Astrophysical Journal; 29 pages, 20
figures, 6 table
WISDOM Project -- VII. Molecular gas measurement of the supermassive black hole mass in NGC 7052
Supermassive black hole (SMBH) masses can be measured by resolving the
dynamical influences of the SMBHs on spatially-resolved tracers of the central
potentials. Modern long-baseline interferometers have enabled the use of
molecular gas as such a tracer. We present here Atacama Large
Millimeter/submillimeter Array observations of the elliptical galaxy NGC 7052
at 0.11 arcseconds (37 pc) resolution in the 12CO(2-1) line and 1.3mm continuum
emission. This resolution is sufficient to resolve the region in which the
potential is dominated by the SMBH. We forward model these observations, using
a multi-Gaussian expansion of a Hubble Space Telescope F814W image and
spatially-constant mass-to-light ratio to model the stellar mass distribution.
We infer a SMBH mass of and a stellar
I-band mass-to-light ratio of
( confidence intervals). This SMBH mass is significantly larger than
that derived using ionised gas kinematics, which however appear significantly
more kinematically disturbed than the molecular gas. We also show that a
central molecular gas deficit is likely to be the result of tidal disruption of
molecular gas clouds due to the strong gradient in the central gravitational
potential.Comment: 14 pages, 8 figures, accepted for publication in MNRA
WISDOM project { IV. A molecular gas dynamical measurement of the supermassive black hole mass in NGC 524
We present high angular resolution (0.3" or 37 pc) Atacama Large
Millimeter/sub-millimeter Array (ALMA) observations of the CO(2-1) line
emission from a central disc in the early-type galaxy NGC 524. This disc is
shown to be dynamically relaxed, exhibiting ordered rotation about a compact
1.3mm continuum source, which we identify as emission from an active
supermassive black hole (SMBH). There is a hole at the centre of the disc
slightly larger than the SMBH sphere of influence. An azimuthal distortion of
the observed velocity field is found to be due to either a position angle warp
or radial gas flow over the inner 2.5". By forward-modelling the observations,
we obtain an estimate of the SMBH mass of
, where the uncertainties are at
the level. The uncertainties are dominated by the poorly constrained
inclination and the stellar mass-to-light ratio of this galaxy, and our
measurement is consistent with the established correlation between SMBH mass
and stellar velocity dispersion. Our result is roughly half that of the
previous stellar dynamical measurement, but is consistent within the
uncertainties of both. We also present and apply a new tool for modelling
complex molecular gas distributions.Comment: 17 pages, 9 figures, accepted for publication in MNRA
Revealing the intermediate-mass black hole at the heart of the dwarf galaxy NGC404 with sub-parsec resolution ALMA observations
We estimate the mass of the intermediate-mass black hole at the heart of the dwarf elliptical galaxy NGC 404 using Atacama Large Millimeter/submillimeter Array( ALMA) observations of the molecular interstellar medium at an unprecedented linear resolution of ≈0.5pc, in combination with existing stellar kinematic information. These ALMA observations reveal a central disc/torus of molecular gas clearly rotating around the black hole. This disc is surrounded by a morphologically and kinematically complex flocculent distribution of molecular clouds, that we resolve in detail. Continuum emission is detected from the central parts of NGC404, likely arising from the Rayleigh–Jeans tail of emission from dust around the nucleus, and potentially from dusty massive star-forming clumps at discrete locations in the disc. Several dynamical measurements of the black hole mass in this system have been made in the past, but they do not agree. We show here that both the observed molecular gas and stellar kinematics independently require a ≈5×105M black hole once we include the contribution of the molecular gas to the potential. Our best estimate comes from the high-resolution molecular gas kinematics, suggesting the black hole mass of this system is 5.5+4.1 −3.8×105 M (at the 99% confidence level), in good agreement with our revised stellar kinematic measurement and broadly consistent with extrapolations from the black hole mass–velocity dispersion and black hole mass – bulge mass relations. This highlights the need to accurately determine the mass and distribution of each dynamically important component around intermediate-mass black holes when attempting to estimate their masses
WISDOM project - V. Resolving molecular gas in Keplerian rotation around the supermassive black hole in NGC0383
As part of the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM), we present a measurement of the mass of the supermassive black hole (SMBH) in the nearby early-type galaxy NGC 0383 (radio source 3C 031). This measurement is based on Atacama Large Millimeter/sub-milimeter Array (ALMA) cycle 4 and 5 observations of the 12CO(2–1) emission line with a spatial resolution of 58 × 32 pc2 (0 ′′ .
.′′
18 × 0 ′′ .
.′′
1). This resolution, combined with a channel width of 10 km s−1, allows us to well resolve the radius of the black hole sphere of influence (measured as RSOI = 316 pc = 0 ′′ .
.′′
98), where we detect a clear Keplerian increase of the rotation velocities. NGC 0383 has a kinematically-relaxed, smooth nuclear molecular gas disc with weak ring/spiral features. We forward-model the ALMA data cube with the Kinematic Molecular Simulation (KinMS) tool and a Bayesian Markov Chain Monte Carlo method to measure a SMBH mass of (4.2 ± 0.7) × 109 M⊙, a F160W-band stellar mass-to-light ratio that varies from 2.8 ± 0.6 M⊙/L⊙, F160W in the centre to 2.4 ± 0.3 M⊙/L ⊙,F160W
/L⊙,F160W
at the outer edge of the disc and a molecular gas velocity dispersion of 8.3 ± 2.1 km s−1(all 3σ uncertainties). We also detect unresolved continuum emission across the full bandwidth, consistent with synchrotron emission from an active galactic nucleus. This work demonstrates that low-J CO emission can resolve gas very close to the SMBH (≈140 000 Schwarzschild radii) and hence that the molecular gas method is highly complimentary to megamaser observations as it can probe the same emitting material
Maximising retention in a longitudinal study of genital Chlamydia trachomatis among young women in Australia
<p>Abstract</p> <p>Background</p> <p>Cohort studies are an important study design however they are difficult to implement, often suffer from poor retention, low participation and bias. The aims of this paper are to describe the methods used to recruit and retain young women in a longitudinal study and to explore factors associated with loss to follow up.</p> <p>Methods</p> <p>The Chlamydia Incidence and Re-infection Rates Study (CIRIS) was a longitudinal study of Australian women aged 16 to 25 years recruited from primary health care clinics. They were followed up via the post at three-monthly intervals and required to return questionnaires and self collected vaginal swabs for chlamydia testing. The protocol was designed to maximise retention in the study and included using recruiting staff independent of the clinic staff, recruiting in private, regular communication with study staff, making the follow up as straightforward as possible and providing incentives and small gifts to engender good will.</p> <p>Results</p> <p>The study recruited 66% of eligible women. Despite the nature of the study (sexual health) and the mobility of the women (35% moved address at least once), 79% of the women completed the final stage of the study after 12 months. Loss to follow up bias was associated with lower education level [adjusted hazard ratio (AHR): 0.7 (95% Confidence Interval (CI): 0.5, 1.0)], recruitment from a sexual health centre as opposed to a general practice clinic [AHR: 1.6 (95% CI: 1.0, 2.7)] and previously testing positive for chlamydia [AHR: 0.8 (95% CI: 0.5, 1.0)]. No other factors such as age, numbers of sexual partners were associated with loss to follow up.</p> <p>Conclusions</p> <p>The methods used were considered effective for recruiting and retaining women in the study. Further research is needed to improve participation from less well-educated women.</p
Maximising retention in a longitudinal study of genital Chlamydia trachomatis among young women in Australia
<p>Abstract</p> <p>Background</p> <p>Cohort studies are an important study design however they are difficult to implement, often suffer from poor retention, low participation and bias. The aims of this paper are to describe the methods used to recruit and retain young women in a longitudinal study and to explore factors associated with loss to follow up.</p> <p>Methods</p> <p>The Chlamydia Incidence and Re-infection Rates Study (CIRIS) was a longitudinal study of Australian women aged 16 to 25 years recruited from primary health care clinics. They were followed up via the post at three-monthly intervals and required to return questionnaires and self collected vaginal swabs for chlamydia testing. The protocol was designed to maximise retention in the study and included using recruiting staff independent of the clinic staff, recruiting in private, regular communication with study staff, making the follow up as straightforward as possible and providing incentives and small gifts to engender good will.</p> <p>Results</p> <p>The study recruited 66% of eligible women. Despite the nature of the study (sexual health) and the mobility of the women (35% moved address at least once), 79% of the women completed the final stage of the study after 12 months. Loss to follow up bias was associated with lower education level [adjusted hazard ratio (AHR): 0.7 (95% Confidence Interval (CI): 0.5, 1.0)], recruitment from a sexual health centre as opposed to a general practice clinic [AHR: 1.6 (95% CI: 1.0, 2.7)] and previously testing positive for chlamydia [AHR: 0.8 (95% CI: 0.5, 1.0)]. No other factors such as age, numbers of sexual partners were associated with loss to follow up.</p> <p>Conclusions</p> <p>The methods used were considered effective for recruiting and retaining women in the study. Further research is needed to improve participation from less well-educated women.</p
Differential In Vitro Effects of Intravenous versus Oral Formulations of Silibinin on the HCV Life Cycle and Inflammation
Silymarin prevents liver disease in many experimental rodent models, and is the most popular botanical medicine consumed by patients with hepatitis C. Silibinin is a major component of silymarin, consisting of the flavonolignans silybin A and silybin B, which are insoluble in aqueous solution. A chemically modified and soluble version of silibinin, SIL, has been shown to potently reduce hepatitis C virus (HCV) RNA levels in vivo when administered intravenously. Silymarin and silibinin inhibit HCV infection in cell culture by targeting multiple steps in the virus lifecycle. We tested the hepatoprotective profiles of SIL and silibinin in assays that measure antiviral and anti-inflammatory functions. Both mixtures inhibited fusion of HCV pseudoparticles (HCVpp) with fluorescent liposomes in a dose-dependent fashion. SIL inhibited 5 clinical genotype 1b isolates of NS5B RNA dependent RNA polymerase (RdRp) activity better than silibinin, with IC50 values of 40–85 µM. The enhanced activity of SIL may have been in part due to inhibition of NS5B binding to RNA templates. However, inhibition of the RdRps by both mixtures plateaued at 43–73%, suggesting that the products are poor overall inhibitors of RdRp. Silibinin did not inhibit HCV replication in subgenomic genotype 1b or 2a replicon cell lines, but it did inhibit JFH-1 infection. In contrast, SIL inhibited 1b but not 2a subgenomic replicons and also inhibited JFH-1 infection. Both mixtures inhibited production of progeny virus particles. Silibinin but not SIL inhibited NF-κB- and IFN-B-dependent transcription in Huh7 cells. However, both mixtures inhibited T cell proliferation to similar degrees. These data underscore the differences and similarities between the intravenous and oral formulations of silibinin, which could influence the clinical effects of this mixture on patients with chronic liver diseases
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