109 research outputs found
Use of glycoprotein IIb/IIIa antagonists to prevent stent thrombosis in morphine-treated patients with ST-elevation myocardial infarction
Morphine can delay absorption of P2Y12-inhibitors in ST-elevation myocardial infarction (STEMI) patients, which has the potential to expose these patients to increased stent thrombosis risk after primary percutaneous coronary intervention (PPCI). Limited evidence exists for pharmacotherapeutic strategies aiming to mitigate this risk. We evaluated the impact of guideline-driven ‘routine’ glycoprotein IIb/IIIa antagonist (GPI) use in morphine-treated patients undergoing PPCI. A total of 3224 consecutive STEMI patients undergoing PPCI at a large tertiary cardiac center between 2012 and 2017 were evaluated. GPI use and outcomes before and after introduction of a local guideline were compared, and rates of definite stent thrombosis were identified at 24 h and 30 days. GPI use increased from 42.4% to 69.9% after the introduction of the new guideline. Stent thrombosis occurred in 1.3% (26/1947) pre-guideline and 0.6% (7/1244) post-guideline (P = .037). Of the 33 stent thrombosis cases, 90% (27/30) had received morphine, of whom 85.2% (23/27) had not received adjunctive GPI. Complete records for assessing 30-day bleeding rates were only available in 374 patients and, in this subset, there was no significant difference in rates of GUSTO moderate or severe bleeding before vs. after introduction of the local guideline (1.7% vs 2.8%; P = .47) although, in both cohorts combined, any GUSTO bleeding was observed more frequently in GPI-treated patients (21.8%) compared to those not receiving a GPI (10.0%; P = .002). In conclusion, routine GPI use in morphine-treated STEMI patients undergoing PPCI appears to protect against stent thrombosis. Large-scale studies are needed to establish the overall risk-benefit of GPI therapy in morphine-treated PPCI patients and to assess alternative strategies for preventing acute stent thrombosis in these patients
Sex differences in coronary microvascular resistance measured by a computational fluid dynamics model
BackgroundIncreased coronary microvascular resistance (CMVR) is associated with coronary microvascular dysfunction (CMD). Although CMD is more common in women, sex-specific differences in CMVR have not been demonstrated previously.AimTo compare CMVR between men and women being investigated for chest pain.Methods and resultsWe used a computational fluid dynamics (CFD) model of human coronary physiology to calculate absolute CMVR based on invasive coronary angiographic images and pressures in 203 coronary arteries from 144 individual patients. CMVR was significantly higher in women than men (860 [650–1,205] vs. 680 [520–865] WU, Z = −2.24, p = 0.025). None of the other major subgroup comparisons yielded any differences in CMVR.ConclusionCMVR was significantly higher in women compared with men. These sex-specific differences may help to explain the increased prevalence of CMD in women
Validation of a novel numerical model to predict regionalized blood flow in the coronary arteries
Aims: Ischaemic heart disease results from insufficient coronary blood flow. Direct measurement of absolute flow (mL/min) is feasible, but has not entered routine clinical practice in most catheterization laboratories. Interventional cardiologists, therefore, rely on surrogate markers of flow. Recently, we described a computational fluid dynamics (CFD) method for predicting flow that differentiates inlet, side branch, and outlet flows during angiography. In the current study, we evaluate a new method that regionalizes flow along the length of the artery. Methods and results: Three-dimensional coronary anatomy was reconstructed from angiograms from 20 patients with chronic coronary syndrome. All flows were computed using CFD by applying the pressure gradient to the reconstructed geometry. Side branch flow was modelled as a porous wall boundary. Side branch flow magnitude was based on morphometric scaling laws with two models: a homogeneous model with flow loss along the entire arterial length; and a regionalized model with flow proportional to local taper. Flow results were validated against invasive measurements of flow by continuous infusion thermodilution (Coroventis™, Abbott). Both methods quantified flow relative to the invasive measures: homogeneous (r 0.47, P 0.006; zero bias; 95% CI -168 to +168 mL/min); regionalized method (r 0.43, P 0.013; zero bias; 95% CI -175 to +175 mL/min). Conclusion: During angiography and pressure wire assessment, coronary flow can now be regionalized and differentiated at the inlet, outlet, and side branches. The effect of epicardial disease on agreement suggests the model may be best targeted at cases with a stenosis close to side branches.</p
Leptin interacts with glucagon-like peptide-1 neurons to reduce food intake and body weight in rodents
AbstractThe adipose tissue hormone, leptin, and the neuropeptide glucagon-like peptide-1 (7–36) amide (GLP-1) both reduce food intake and body weight in rodents. Using dual in situ hybridization, long isoform leptin receptor (OB-Rb) was localized to GLP-1 neurons originating in the nucleus of the solitary tract. ICV injection of the specific GLP-1 receptor antagonist, exendin(9–39), at the onset of dark phase, did not affect feeding in saline pre-treated controls, but blocked the reduction in food intake and body weight of leptin pre-treated rats. These findings suggest that GLP-1 neurons are a potential target for leptin in its control of feeding
A Catalog of Broad Absorption Line Quasars from the Sloan Digital Sky Survey Early Data Release
We present a catalog of 224 broad absorption line quasars (BALQSOs) from the
Sloan Digital Sky Survey's Early Data Release Quasar Catalog, including a
relatively complete and homogeneous subsample of 131 BALQSOs. Since the
identification of BALQSOs is subject to considerable systematic uncertainties,
we attempt to create a complete sample of SDSS BALQSOs by combining the results
of two automated selection algorithms and a by-eye classification scheme. One
of these automated algorithms finds broad absorption line troughs by comparison
with a composite quasar spectrum. We present the details of this algorithm and
compare this method to that which uses a power-law fit to the continuum. The
BALQSOs in our sample are further classified as high-ionization BALQSOs
(HiBALs), low-ionization BALQSOs (LoBALs), and BALQSOs with excited iron
absorption features (FeLoBALs); composite spectra of each type are presented.
We further present a study of the properties of the BALQSOs in terms of the
balnicity distribution, which rises with decreasing balnicity. This
distribution of balnicities suggests that the fraction of quasars with
intrinsic outflows may be significantly underestimated.Comment: 36 pages, 7 figures (1 color), 2 tables, accepted by A
The Baryon Oscillation Spectroscopic Survey of SDSS-III
The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the
scale of baryon acoustic oscillations (BAO) in the clustering of matter over a
larger volume than the combined efforts of all previous spectroscopic surveys
of large scale structure. BOSS uses 1.5 million luminous galaxies as faint as
i=19.9 over 10,000 square degrees to measure BAO to redshifts z<0.7.
Observations of neutral hydrogen in the Lyman alpha forest in more than 150,000
quasar spectra (g<22) will constrain BAO over the redshift range 2.15<z<3.5.
Early results from BOSS include the first detection of the large-scale
three-dimensional clustering of the Lyman alpha forest and a strong detection
from the Data Release 9 data set of the BAO in the clustering of massive
galaxies at an effective redshift z = 0.57. We project that BOSS will yield
measurements of the angular diameter distance D_A to an accuracy of 1.0% at
redshifts z=0.3 and z=0.57 and measurements of H(z) to 1.8% and 1.7% at the
same redshifts. Forecasts for Lyman alpha forest constraints predict a
measurement of an overall dilation factor that scales the highly degenerate
D_A(z) and H^{-1}(z) parameters to an accuracy of 1.9% at z~2.5 when the survey
is complete. Here, we provide an overview of the selection of spectroscopic
targets, planning of observations, and analysis of data and data quality of
BOSS.Comment: 49 pages, 16 figures, accepted by A
Active Galactic Nuclei in the Sloan Digital Sky Survey: II. Emission-Line Luminosity Function
The emission line luminosity function of active galactic nuclei (AGN) is
measured from about 3000 AGN included in the main galaxy sample of the Sloan
Digital Sky Survey within a redshift range of . The \Ha and
[OIII] luminosity functions for Seyferts cover luminosity range
of in H and the shapes are well fit by broken power
laws, without a turnover at fainter nuclear luminosities. Assuming a universal
conversion from emission line strength to continuum luminosity, the inferred B
band magnitude luminosity function is comparable both to the AGN luminosity
function of previous studies and to the low redshift quasar luminosity function
derived from the 2dF redshift survey. The inferred AGN number density is
approximately 1/5 of all galaxies and about of the total
light of galaxies in the -band comes from the nuclear activity. The numbers
of Seyfert 1s and Seyfert 2s are comparable at low luminosity, while at high
luminosity, Seyfert 1s outnumber Seyfert 2s by a factor of 2-4. In making the
luminosity function measurements, we assumed that the nuclear luminosity is
independent of the host galaxy luminosity, an assumption we test {\it a
posteriori}, and show to be consistent with the data. Given the relationship
between black hole mass and host galaxy bulge luminosity, the lack of
correlation between nuclear and host luminosity suggests that the main variable
that determines the AGN luminosity is the Eddington ratio, not the black hole
mass. This appears to be different from luminous quasars, which are most likely
to be shining near the Eddington limit.Comment: AASTeX v5.02 preprint; 35 pages, including 2 table and 12 figures. To
appear in the April 2005 issue of AJ. See astro-ph/0501059 for Paper
The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic
data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data
release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median
z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar
spectra, along with the data presented in previous data releases. These spectra
were obtained with the new BOSS spectrograph and were taken between 2009
December and 2011 July. In addition, the stellar parameters pipeline, which
determines radial velocities, surface temperatures, surface gravities, and
metallicities of stars, has been updated and refined with improvements in
temperature estimates for stars with T_eff<5000 K and in metallicity estimates
for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars
presented in DR8, including stars from SDSS-I and II, as well as those observed
as part of the SDSS-III Sloan Extension for Galactic Understanding and
Exploration-2 (SEGUE-2).
The astrometry error introduced in the DR8 imaging catalogs has been
corrected in the DR9 data products. The next data release for SDSS-III will be
in Summer 2013, which will present the first data from the Apache Point
Observatory Galactic Evolution Experiment (APOGEE) along with another year of
data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at
http://www.sdss3.org/dr
Evaluation of models of sequestration flow in coronary arteries—Physiology versus anatomy?
Background:
Myocardial ischaemia results from insufficient coronary blood flow. Computed virtual fractional flow reserve (vFFR) allows quantification of proportional flow loss without the need for invasive pressure-wire testing. In the current study, we describe a novel, conductivity model of side branch flow, referred to as ‘leak’. This leak model is a function of taper and local pressure, the latter of which may change radically when focal disease is present. This builds upon previous techniques, which either ignore side branch flow, or rely purely on anatomical factors. This study aimed to describe a new, conductivity model of side branch flow and compare this with established anatomical models.
Methods and results:
The novel technique was used to quantify vFFR, distal absolute flow (Qd) and microvascular resistance (CMVR) in 325 idealised 1D models of coronary arteries, modelled from invasive clinical data. Outputs were compared to an established anatomical model of flow. The conductivity model correlated and agreed with the reference model for vFFR (r = 0.895, p
<
0.0001; +0.02, 95% CI 0.00 to + 0.22), Qd (r = 0.959, p
<
0.0001; −5.2 mL/min, 95% CI −52.2 to +13.0) and CMVR (r = 0.624, p
<
0.0001; +50 Woods Units, 95% CI −325 to +2549).
Conclusion:
Agreement between the two techniques was closest for vFFR, with greater proportional differences seen for Qd and CMVR. The conductivity function assumes vessel taper was optimised for the healthy state and that CMVR was not affected by local disease. The latter may be addressed with further refinement of the technique or inferred from complementary image data.The conductivity technique may represent a refinement of current techniques for modelling coronary side-branch flow. Further work is needed to validate the technique against invasive clinical data
Convergence of marine megafauna movement patterns in coastal and open oceans
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 115 (2018): 3072-3077, doi:10.1073/pnas.1716137115.The extent of increasing anthropogenic impacts on large marine
vertebrates partly depends on the animals’ movement patterns.
Effective conservation requires identification of the key drivers of
movement including intrinsic properties and extrinsic constraints
associated with the dynamic nature of the environments the animals
inhabit. However, the relative importance of intrinsic versus
extrinsic factors remains elusive. We analyse a global dataset of
2.8 million locations from > 2,600 tracked individuals across 50
marine vertebrates evolutionarily separated by millions of years
and using different locomotion modes (fly, swim, walk/paddle).
Strikingly, movement patterns show a remarkable convergence,
being strongly conserved across species and independent of body
length and mass, despite these traits ranging over 10 orders of
magnitude among the species studied. This represents a fundamental
difference between marine and terrestrial vertebrates not
previously identified, likely linked to the reduced costs of locomotion
in water. Movement patterns were primarily explained by the
interaction between species-specific traits and the habitat(s) they
move through, resulting in complex movement patterns when
moving close to coasts compared to more predictable patterns
when moving in open oceans. This distinct difference may be
associated with greater complexity within coastal micro-habitats,
highlighting a critical role of preferred habitat in shaping marine
vertebrate global movements. Efforts to develop understanding
of the characteristics of vertebrate movement should consider the
habitat(s) through which they move to identify how movement
patterns will alter with forecasted severe ocean changes, such as
reduced Arctic sea ice cover, sea level rise and declining oxygen
content.Workshops funding granted by the UWA Oceans Institute, AIMS, and
KAUST. AMMS was supported by an ARC Grant DE170100841 and an IOMRC
(UWA, AIMS, CSIRO) fellowship; JPR by MEDC (FPU program, Spain); DWS by
UK NERC and Save Our Seas Foundation; NQ by FCT (Portugal); MMCM by
a CAPES fellowship (Ministry of Education)
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