Emory University

About: Emory University is a education organization based out in Atlanta, Georgia, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 51959 authors who have published 122469 publications receiving 6010698 citations.

Lineage relationship and protective immunity of memory CD8 T cell subsets.

Abstract: Memory CD8 T cells can be divided into two subsets, central (TCM) and effector (TEM), but their lineage relationships and their ability to persist and confer protective immunity are not well understood. Our results show that TCM have a greater capacity than TEM to persist in vivo and are more efficient in mediating protective immunity because of their increased proliferative potential.We also demonstrate that, following antigen clearance, TEM convert to TCM and that the duration of this differentiation is programmed within the first week after immunization.We propose that TCM and TEM do not necessarily represent distinct subsets, but are part of a continuum in a linear naive → effector → TEM → TCM differentiation pathway.

Matrix Metalloproteinases in Vascular Remodeling and Atherogenesis The Good, the Bad, and the Ugly

Abstract: Vascular remodeling, defined as any enduring change in the size and/or composition of an adult blood vessel, allows adaptation and repair. On the other hand, inappropriate remodeling, including its absence, underlies the pathogenesis of major cardiovascular diseases, such as atherosclerosis and restenosis. Since degradation of the extracellular matrix scaffold enables reshaping of tissue, participation of specialized enzymes called matrix metalloproteinases (MMPs) has become the object of intense recent interest in relation to physiological ("good") and pathological ("bad") vascular remodeling. Experimental evidence acquired in vitro and in vivo suggests that the major drivers of vascular remodeling, hemodynamics, injury, inflammation, and oxidative stress, regulate MMP expression and activity. Alternatively, nonspecific MMP inhibition seems to oppose remodeling, as suggested by the inhibition of intimal thickening and outward arterial remodeling. An emerging concept is that MMP-related genetic variations may contribute to heterogeneity in the presentation and natural history of atherosclerosis. The hypothesis that MMPs contribute to weakening of atherosclerotic plaques is especially attractive for the potential development of therapeutic interventions aimed at preventing plaque disruption ("the ugly"), a major cause of acute cardiovascular events. However, the current lack of appropriate experimental tools, including availability of specific MMP inhibitors and pertinent animal models, still limits our understanding of the many actions and relative contributions of specific MMPs. Our future potential ability to control vascular remodeling via regulation of MMPs will also depend on reaching a consensus of what is indeed "good" or "bad" vascular remodeling, concepts that have continued to evolve and change.

Hypercholesterolemia increases endothelial superoxide anion production.

Abstract: Indirect evidence suggests accelerated degradation of endothelium-derived nitric oxide (ENDO) by superoxide anion (O2-) in hypercholesterolemic vessels (HV) To directly measure O2- production by normal vessels (NV) and HV, we used an assay for O2- based on the chemiluminescence (CL) of lucigenin (L) HV (1 mo cholesterol-fed rabbits) produced threefold more O2- than NV (147 +/- 020 nM/mg tissue/min, n = 7 vs 052 +/- 005 nmol/mg tissue/min, n = 8, P < 0001) Endothelial removal increased O2- production in NV (073 +/- 008, n = 6, P < 005), while decreasing it in HV (076 +/- 015, n = 5, P < 005) There was no difference between denuded HV and denuded NV Oxypurinol, a noncompetitive inhibitor of xanthine oxidase, normalized O2- production in HV, but had no effect in NV In separate isometric tension studies treatment with oxypurinol improved acetylcholine induced relaxations in HV, while having no effect on responses in normal vessels Oxypurinol did not alter relaxations to nitroprusside Thus, the endothelium is a source of O2- in hypercholesterolemia probably via xanthine oxidase activation Increased endothelial O2- production in HV may inactivate endothelium-derived nitric oxide and provide a source for other oxygen radicals, contributing to the early atherosclerotic process

A new oniom implementation in gaussian98. part i. the calculation of energies, gradients, vibrational frequencies and electric field derivatives

Abstract: The IMOMM, IMOMO, and ONIOM methods have been proven to be powerful tools for the theoretical treatment of large molecular systems where different levels of theory are applied to different parts of a molecule. Within this framework we present a modified handling of the link atoms which are introduced to terminate the dangling bonds of the model system. Using this new scheme the definition of the combined energy gradient, the Hessian matrix, and the integration of higher derivatives of the energy with respect to nuclear coordinates and the electric field vector becomes straightforward. This allows for the first time the consistent combination of vibrational frequencies and the calculation of other molecular properties such as IR intensities, Raman intensities as well as dipole moments, polarizabilities, and hyperpolarizabilities. Test calculations for some typical as well as unusual examples and partitioning schemes are presented to demonstrate the power and limitations of the method and to provide guidelines for its applicability. Users of the method are strongly advised to test, calibrate and confirm for themselves the validity of the method combination and the model subsystem for the properties they want to calculate.