Role of the endothelium and COX-1 in prostacyclin generation by whole vessels stimulated with different agonists

Prostacyclin is an important cardioprotective hormone produced by the vascular wall, whose synthesis is dependent on cyclo-oxygenase (COX) enzymes. In healthy vessels the endothelium is thought to be the main site of prostacyclin release (Moncada et al 1977). Two isoforms of COX exist, and we have recently published data demonstrating that it is COX-1 rather than COX-2 that drives the production of prostacyclin in mouse aorta (Kirkby et al 2012). In this study we aimed to extend these observations by investigating what proportion of the COX-1 driven aortic prostacyclin production that comes from the endothelium versus the rest of the vessel wall (smooth muscle layers and adventitia). To do this, we explored how removal of the endothelium would influence the ability of aortic tissue to release prostacyclin in response to a range of agonists that are known to activate the endothelium and the vessel wallNon peer reviewe

Role of shear stress in endothelial cell morphology and expression of cyclooxygenase isoforms

MEDLINE® is the source for the MeSH terms of this document.Objective-: The goal of this study was to examine the effect of chronic heterogeneous shear stress, applied using an orbital shaker, on endothelial cell morphology and the expression of cyclooxygenases 1 and 2. Methods and results-: Porcine aortic endothelial cells were plated on fibronectin-coated Transwell plates. Cells were cultured for up to 7 days either under static conditions or on an orbital shaker that generated a wave of medium inducing shear stress over the cells. Cells were fixed and stained for the endothelial surface marker CD31 or cyclooxygenases 1 and 2. En face confocal microscopy and scanning ion conductance microscopy were used to show that endothelial cells were randomly oriented at the center of the well, aligned with shear stress nearer the periphery, and expressed cyclooxygenase-1 under all conditions. Lipopolysaccharide induced cyclooxygenase-2 and the production of 6-keto-prostaglandin F1α in all cells. Conclusion-: Cyclooxygenase-1 is expressed in endothelial cells cultured under chronic shear stress of high or low directionality.Peer reviewedSubmitted Versio

Pharmacological assessment of ibuprofen arginate on platelet aggregation and colon cancer cell killing

This work was funded in part by grants from the Wellcome Trust (0852551Z108/Z, to J.A.M.) and British Heart Foundation (FS/16/1/31699, to NSK). SM is a recipient of a PhD award from the King of Saud University, AT is a recipient of a MRC PhD studentship

Tri-meson-mixing of π\pi-η\eta-η′\eta' and ρ\rho-ω\omega-ϕ\phi in the light-cone quark model

The radiative transition form factors of the pseudoscalar mesons {$\pi$, $\eta$, $\eta'$} and the vector mesons {$\rho$, $\omega$, $\phi$} are restudied with $\pi$-$\eta$-$\eta'$ and $\rho$-$\omega$-$\phi$ in tri-meson-mixing pattern, which is described by tri-mixing matrices in the light-cone constituent quark model. The experimental transition decay widths are better reproduced with tri-meson-mixing than previous results in a two-mixing-angle scenario of only two-meson $\eta$-$\eta'$ mixing and $\omega$-$\phi$ mixing.Comment: 8 pages, 6 figures, final version to appear in EPJ

Can forest management based on natural disturbances maintain ecological resilience?

Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance

Demonstration of the temporal matter-wave Talbot effect for trapped matter waves

We demonstrate the temporal Talbot effect for trapped matter waves using ultracold atoms in an optical lattice. We investigate the phase evolution of an array of essentially non-interacting matter waves and observe matter-wave collapse and revival in the form of a Talbot interference pattern. By using long expansion times, we image momentum space with sub-recoil resolution, allowing us to observe fractional Talbot fringes up to 10th order.Comment: 17 pages, 7 figure

Azimuthal anisotropy and correlations in p+p, d+Au and Au+Au collisions at 200 GeV

We present the first measurement of directed flow ($v_1$) at RHIC. $v_1$ is found to be consistent with zero at pseudorapidities $\eta$ from -1.2 to 1.2, then rises to the level of a couple of percent over the range $2.4 < |\eta| < 4$. The latter observation is similar to data from NA49 if the SPS rapidities are shifted by the difference in beam rapidity between RHIC and SPS. Back-to-back jets emitted out-of-plane are found to be suppressed more if compared to those emitted in-plane, which is consistent with {\it jet quenching}. Using the scalar product method, we systematically compared azimuthal correlations from p+p, d+Au and Au+Au collisions. Flow and non-flow from these three different collision systems are discussed.Comment: Quark Matter 2004 proceeding, 4 pages, 3 figure

Azimuthal anisotropy: the higher harmonics

We report the first observations of the fourth harmonic (v_4) in the azimuthal distribution of particles at RHIC. The measurement was done taking advantage of the large elliptic flow generated at RHIC. The integrated v_4 is about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8) harmonics upper limits on the magnitudes are reported.Comment: 4 pages, 6 figures, contribution to the Quark Matter 2004 proceeding