218 research outputs found
Assessment of left atrial volume before and after pulmonary thromboendarterectomy in chronic thromboembolic pulmonary hypertension.
BackgroundImpaired left ventricular diastolic filling is common in chronic thromboembolic pulmonary hypertension (CTEPH), and recent studies support left ventricular underfilling as a cause. To investigate this further, we assessed left atrial volume index (LAVI) in patients with CTEPH before and after pulmonary thromboendarterectomy (PTE).MethodsForty-eight consecutive CTEPH patients had pre- & post-PTE echocardiograms and right heart catheterizations. Parameters included mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), cardiac index, LAVI, & mitral E/A ratio. Echocardiograms were performed 6 ± 3 days pre-PTE and 10 ± 4 days post-PTE. Regression analyses compared pre- and post-PTE LAVI with other parameters.ResultsPre-op LAVI (mean 19.0 ± 7 mL/m2) correlated significantly with pre-op PVR (R = -0.45, p = 0.001), mPAP (R = -0.28, p = 0.05) and cardiac index (R = 0.38, p = 0.006). Post-PTE, LAVI increased by 18% to 22.4 ± 7 mL/m2 (p = 0.003). This change correlated with change in PVR (765 to 311 dyne-s/cm5, p = 0.01), cardiac index (2.6 to 3.2 L/min/m2, p = 0.02), and E/A (.95 to 1.44, p = 0.002).ConclusionIn CTEPH, smaller LAVI is associated with lower cardiac output, higher mPAP, and higher PVR. LAVI increases by ~20% after PTE, and this change correlates with changes in PVR and mitral E/A. The rapid increase in LAVI supports the concept that left ventricular diastolic impairment and low E/A pre-PTE are due to left heart underfilling rather than inherent left ventricular diastolic dysfunction
Learning and animal movement
Authors acknowledge the following grants for supporting this research: NSERC Discovery (ML and MA-M), NSF DMS-1853465 (WF and EG), and Canada Research Chairs Program (ML and MA-M).Integrating diverse concepts from animal behavior, movement ecology, and machine learning, we develop an overview of the ecology of learning and animal movement. Learning-based movement is clearly relevant to ecological problems, but the subject is rooted firmly in psychology, including a distinct terminology. We contrast this psychological origin of learning with the task-oriented perspective on learning that has emerged from the field of machine learning. We review conceptual frameworks that characterize the role of learning in movement, discuss emerging trends, and summarize recent developments in the analysis of movement data. We also discuss the relative advantages of different modeling approaches for exploring the learning-movement interface. We explore in depth how individual and social modalities of learning can matter to the ecology of animal movement, and highlight how diverse kinds of field studies, ranging from translocation efforts to manipulative experiments, can provide critical insight into the learning process in animal movement.Publisher PDFPeer reviewe
Correlation of left ventricular diastolic filling characteristics with right ventricular overload and pulmonary artery pressure in chronic thromboembolic pulmonary hypertension
AbstractObjectivesThis study was designed to determine a quantitative relationship between right ventricular (RV) pressure overload and left ventricular (LV) diastolic filling characteristics in patients with chronic thromboembolic pulmonary hypertension (CTEPH).BackgroundRight ventricular pressure overload in patients with CTEPH causes abnormal LV diastolic filling. However, a quantitative relationship between RV pressure overload and LV diastolic function has not been established.MethodsWe analyzed pre- and postoperative diastolic mitral inflow velocities and right heart hemodynamic data in 39 consecutive patients with CTEPH over the age of 30 (55 ± 11 years) with mean pulmonary artery pressure >30 mm Hg who underwent pulmonary thromboendarterectomy (PTE).ResultsAfter PTE, mean pulmonary artery pressure (mPAP) decreased from 50 ± 11 to 28 ± 9 mm Hg (p < 0.001) while cardiac output (CO) increased from 4.4 ± 1.1 to 5.7 ± 0.9 l/m (p < 0.001). Mitral E/A ratio (E/A) increased from 0.74 ± 0.22 to 1.48 ± 0.69 (p < 0.001). E/A was < 1.25 in all patients pre-PTE. After PTE, all patients with E/A >1.50 had mPAP <35 mm Hg and CO >5.0 l/min. E/A correlated inversely with mPAP (r = 0.55, p < 0.001) and directly with CO (r = 0.53, p < 0.001).ConclusionsE/A is consistently abnormal in patients with CTEPH and increases post-PTE. Moreover, E/A varies inversely with mPAP and directly with CO. Following PTE, E/A >1.5 correlates with the absence of severe pulmonary hypertension (mPAP >35 mm Hg) and the presence of normal cardiac output (> 5.0 l/m)
Chronic Thromboembolic Pulmonary Hypertension
The pulmonary hypertension (PH) and right heart dysfunction that results from chronic thromboembolic involvement of the pulmonary vascular bed is potentially curable with surgical endarterectomy. Over the past several decades, growing clinical experience has brought about increased recognition of this treatable form of PH. Moreover, advances in cardiothoracic surgical techniques have given an increasing number of patients with chronic thromboembolic PH (CTEPH) a surgical remedy with decreasing perioperative morbidity and mortality risks. The availability of pulmonary hypertensive—specific medical therapy for CTEPH patients with surgically inaccessible disease also has been a positive therapeutic advance over the past several years. However, despite this progress, chronic thromboembolic disease as a sequela of acute pulmonary emboli continues to be underappreciated. Furthermore, even if CTEPH has been appropriately diagnosed, misinterpretation of diagnostic information may lead to the inappropriate exclusion of patients from surgical consideration. This may result in the prescription of pulmonary hypertensive medical therapy in CTEPH patients with potentially surgically correctable disease. This difficulty arises from a lack of objective criteria as to what constitutes surgical chronic thromboembolic disease, which primarily is a result of the variability in surgical experience in specialty centers in the United States. Consequently, clinicians must be wary about using pulmonary hypertensive medications in CTEPH patients. Before prescription, it is important to exclude patients from surgical consideration by consulting a specialized center with expertise in this discipline
Regeneration of oral siphon pigment organs in the ascidian Ciona intestinalis
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Developmental Biology 339 (2010): 374-389, doi:10.1016/j.ydbio.2009.12.040.Ascidians have powerful capacities for regeneration but the underlying mechanisms are
poorly understood. Here we examine oral siphon regeneration in the solitary ascidian Ciona
intestinalis. Following amputation, the oral siphon rapidly reforms oral pigment organs (OPO)
at its distal margin prior to slower regeneration of proximal siphon parts. The early stages of oral
siphon reformation include cell proliferation and re-growth of the siphon nerves, although the
neural complex (adult brain and associated organs) is not required for regeneration. Young
animals reform OPO more rapidly after amputation than old animals indicating that regeneration
is age dependent. UV irradiation, microcautery, and cultured siphon explant experiments
indicate that OPOs are replaced as independent units based on local differentiation of progenitor
cells within the siphon, rather than by cell migration from a distant source in the body. The
typical pattern of eight OPOs and siphon lobes is restored with fidelity after distal amputation of
the oral siphon, but as many as sixteen OPOs and lobes can be reformed following proximal
amputation near the siphon base. Thus, the pattern of OPO regeneration is determined by cues
positioned along the proximal distal axis of the oral siphon. A model is presented in which
columns of siphon tissue along the proximal-distal axis below pre-existing OPO are responsible
for reproducing the normal OPO pattern during regeneration. This study reveals previously
unknown principles of oral siphon and OPO regeneration that will be important for developing
Ciona as a regeneration model in urochordates, which may be the closest living relatives of
vertebrates.This research was supported
by PhD fellowships from MRT and ARC to HA, Grants-in-Aid from MEXT, Japan, and the NIJ
Cooperative Program (2008-B02) to YS, INRA, CNRS, the ANR Grant Choregnet, and the
Marine Genomics Center of Excellence to J-SJ, Laura and Arthur Colwin and Frederick Bang
Fellowships from the Marine Biological Laboratory, Woods Hole, MA to WRJ., and NSF grant
(IBN-0611529) to WRJ
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
The ADAMTS13-VWF axis is dysregulated in chronic thromboembolic pulmonary hypertension
Chronic thromboembolic pulmonary hypertension (CTEPH) is an important consequence of pulmonary embolism that is associated with abnormalities in haemostasis. We investigated the ADAMTS13-von Willebrand factor (VWF) axis in CTEPH, including its relationship with disease severity, inflammation, ABO groups and ADAMTS13 genetic variants.ADAMTS13 and VWF plasma antigen levels were measured in patients with CTEPH (n=208), chronic thromboembolic disease without pulmonary hypertension (CTED) (n=35), resolved pulmonary embolism (n=28), idiopathic pulmonary arterial hypertension (n=30) and healthy controls (n=68). CTEPH genetic ABO associations and protein quantitative trait loci were investigated. ADAMTS13-VWF axis abnormalities were assessed in CTEPH and healthy control subsets by measuring ADAMTS13 activity, D-dimers and VWF multimeric size.Patients with CTEPH had decreased ADAMTS13 (adjusted β -23.4%, 95% CI -30.9- -15.1%, p<0.001) and increased VWF levels (β +75.5%, 95% CI 44.8-113%, p<0.001) compared to healthy controls. ADAMTS13 levels remained low after reversal of pulmonary hypertension by pulmonary endarterectomy surgery and were equally reduced in CTED. We identified a genetic variant near the ADAMTS13 gene associated with ADAMTS13 protein that accounted for ∼8% of the variation in levels.The ADAMTS13-VWF axis is dysregulated in CTEPH. This is unrelated to pulmonary hypertension, disease severity or markers of systemic inflammation and implicates the ADAMTS13-VWF axis in CTEPH pathobiology
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
The relationship between consumer ethnocentrism, cosmopolitanism and product country image among younger generation consumers: the moderating role of country development status
Although the differences between developed and developing countries have been extensively studied in the context of globalization strategies, few studies have so far been conducted on the relationship between country development status and the possession by countries of a favorable (or unfavorable) product country image (PCI). Moreover, the results of such studies to date have been inconclusive. The purpose of this paper is to investigate the moderating role of country developmental status on PCI coupled with two antecedents of PCI, namely consumer ethnocentrism and cosmopolitanism. The paper also distinguishes between the PCI of the home and foreign country images of respondents. We test a new model that incorporates these constructs with a sample of 2655 younger generation consumers. The results show that country development status moderates some relationships but does not moderate others. These findings have significant implications for international companies from both developed and developing countries when developing global strategy
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