26,452 research outputs found
A comparison of sequential total and activated white cell count in patients undergoing coronary artery bypass grafting, using cardiopulmonary bypass, with and without a white cell filter
Introduction
Cardiopulmonary bypass (CPB) has been shown to induce a systemic inflammatory response similar to the local reaction seen after tissue damage [1]. This leads to the release of toxic substances, such as elastase, which cause endothelial damage and may adversely affect outcome [2]. Use of a leucocyte depleting arterial line filter is one of many anti-inflammatory strategies that are undergoing evaluation. Leucocyte depleting filters may be capable of selectively removing activated white cells [3], but this has not been proved in vivo. The aim of the present study was to compare sequential total and activated white cells during CPB, using either a leucocyte depleting or standard arterial line filter.
Materials and methods
After local ethical committee approval, 20 patients undergoing coronary artery bypass grafting using CPB were prospectively randomly allocated to have either a Leukogard LG–6 (Pall Biomedical, Portsmouth, UK) or a nonleucocyte depleting filter inserted into the arterial line of the CPB circuit. Arterial limb blood samples were taken immediately after institution of CPB (0min) and at 10–min intervals throughout the bypass period. Activated white cells were identified using nitroblue tetrazolium, then both total and activated white cell numbers counted after staining with Leucoplate.Results
Table 1 shows the number of white cells counted/1.25 ? l (volume of a single channel of Nageotte counting chamber) using light microscopy (× 25).Conclusion
The LG6 leucocyte filter reduces the total white cell count and is capable of selectively removing activated white cells during CPB. The exact relationship between leucocyte depletion and improved patient outcome still remains unclear
Parity-Violating Electron Scattering and Neucleon Structure
The measurement of parity violation in the helicity dependence of
electron-nucleon scattering provides unique information about the basic quark
structure of the nucleons. In this review, the general formalism of
parity-violating electron scattering is presented, with emphasis on elastic
electron-nucleon scattering. The physics issues addressed by such experiments
is discussed, and the major goals of the presently envisioned experimental
program are identified. %General aspects of the experimental technique are
reviewed and A summary of results from a recent series of experiments is
presented and the future prospects of this program are also discussed.Comment: 45 pages, 9 figure
Exoplanet Terra Incognita
Exoplanet surface imaging, cartography and the search for exolife are the
next frontiers of planetology and astrophysics. Here we present an over-view of
ideas and techniques to resolve albedo features on exoplanetary surfaces.
Albedo maps obtained in various spectral bands (similar to true-colour images)
may reveal exoplanet terrains, geological history, life colonies, and even
artificial structures of advanced civilizations.Comment: 16 pages, 6 figures, Planetary Cartograph
Revisiting soliton contributions to perturbative amplitudes
Open Access funded by SCOAP3. CP is
a Royal Society Research Fellow and partly supported by the U.S. Department of Energy
under grants DOE-SC0010008, DOE-ARRA-SC0003883 and DOE-DE-SC0007897. ABR
is supported by the Mitchell Family Foundation. We would like to thank the Mitchell
Institute at Texas A&M and the NHETC at Rutgers University respectively for hospitality
during the course of this work. We would also like to acknowledge the Aspen Center for
Physics and NSF grant 1066293 for a stimulating research environment
Modulation of LAT1 (SLC7A5) transporter activity and stability by membrane cholesterol.
LAT1 (SLC7A5) is a transporter for both the uptake of large neutral amino acids and a number of pharmaceutical drugs. It is expressed in numerous cell types including T-cells, cancer cells and brain endothelial cells. However, mechanistic knowledge of how it functions and its interactions with lipids are unknown or limited due to inability of obtaining stable purified protein in sufficient quantities. Our data show that depleting cellular cholesterol reduced the Vmax but not the Km of the LAT1 mediated uptake of a model substrate into cells (L-DOPA). A soluble cholesterol analogue was required for the stable purification of the LAT1 with its chaperon CD98 (4F2hc,SLC3A2) and that this stabilised complex retained the ability to interact with a substrate. We propose cholesterol interacts with the conserved regions in the LAT1 transporter that have been shown to bind to cholesterol/CHS in Drosophila melanogaster dopamine transporter. In conclusion, LAT1 is modulated by cholesterol impacting on its stability and transporter activity. This novel finding has implications for other SLC7 family members and additional eukaryotic transporters that contain the LeuT fold
In vivo assessment of muscle membrane properties in myotonic dystrophy
INTRODUCTION: Myotonia in myotonic dystrophy types 1 (DM1) and 2 (DM2) is generally attributed to reduced chloride channel conductance. We used muscle velocity recovery cycles (MVRCs) to investigate muscle membrane properties in DM1 and DM2, with comparisons with myotonia congenita (MC). METHODS: MVRCs and responses to repetitive stimulation were compared between patients with DM1 (n=18), DM2 (n=5), MC (n=18), and normal controls (n=20). RESULTS: Both DM1 and DM2 showed enhanced late supernormality after multiple conditioning stimuli, indicating delayed repolarization as in MC. Contrary to MC, however, DM1 showed reduced early supernormality after multiple conditioning stimuli, and weak DM1 patients also showed abnormally slow latency recovery after repetitive stimulation. DISCUSSION: These findings support impaired chloride conductance in both DM1 and DM2. The early supernormality changes indicate that sodium currents were reduced in DM1, while the weakness-associated slow recovery after repetitive stimulation may provide an indication of reduced Na(+) /K(+) -ATPase activation
Whole slide image registration for the study of tumor heterogeneity
Consecutive thin sections of tissue samples make it possible to study local
variation in e.g. protein expression and tumor heterogeneity by staining for a
new protein in each section. In order to compare and correlate patterns of
different proteins, the images have to be registered with high accuracy. The
problem we want to solve is registration of gigapixel whole slide images (WSI).
This presents 3 challenges: (i) Images are very large; (ii) Thin sections
result in artifacts that make global affine registration prone to very large
local errors; (iii) Local affine registration is required to preserve correct
tissue morphology (local size, shape and texture). In our approach we compare
WSI registration based on automatic and manual feature selection on either the
full image or natural sub-regions (as opposed to square tiles). Working with
natural sub-regions, in an interactive tool makes it possible to exclude
regions containing scientifically irrelevant information. We also present a new
way to visualize local registration quality by a Registration Confidence Map
(RCM). With this method, intra-tumor heterogeneity and charateristics of the
tumor microenvironment can be observed and quantified.Comment: MICCAI2018 - Computational Pathology and Ophthalmic Medical Image
Analysis - COMPA
Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation II: RT-2/CZT payload
Cadmium Zinc Telluride (CZT) detectors are high sensitivity and high
resolution devices for hard X-ray imaging and spectroscopic studies. The new
series of CZT detector modules (OMS40G256) manufactured by Orbotech Medical
Solutions (OMS), Israel, are used in the RT-2/CZT payload onboard the
CORONAS-PHOTON satellite. The CZT detectors, sensitive in the energy range of
20 keV to 150 keV, are used to image solar flares in hard X-rays. Since these
modules are essentially manufactured for commercial applications, we have
carried out a series of comprehensive tests on these modules so that they can
be confidently used in space-borne systems. These tests lead us to select the
best three pieces of the 'Gold' modules for the RT-2/CZT payload. This paper
presents the characterization of CZT modules and the criteria followed for
selecting the ones for the RT-2/CZT payload. The RT-2/CZT payload carries,
along with three CZT modules, a high spatial resolution CMOS detector for high
resolution imaging of transient X-ray events. Therefore, we discuss the
characterization of the CMOS detector as well.Comment: 26 pages, 19 figures, Accepted for publication in Experimental
Astronomy (in press
The extreme vulnerability of interdependent spatially embedded networks
Recent studies show that in interdependent networks a very small failure in
one network may lead to catastrophic consequences. Above a critical fraction of
interdependent nodes, even a single node failure can invoke cascading failures
that may abruptly fragment the system, while below this "critical dependency"
(CD) a failure of few nodes leads only to small damage to the system. So far,
the research has been focused on interdependent random networks without space
limitations. However, many real systems, such as power grids and the Internet,
are not random but are spatially embedded. Here we analytically and numerically
analyze the stability of systems consisting of interdependent spatially
embedded networks modeled as lattice networks. Surprisingly, we find that in
lattice systems, in contrast to non-embedded systems, there is no CD and
\textit{any} small fraction of interdependent nodes leads to an abrupt
collapse. We show that this extreme vulnerability of very weakly coupled
lattices is a consequence of the critical exponent describing the percolation
transition of a single lattice. Our results are important for understanding the
vulnerabilities and for designing robust interdependent spatial embedded
networks.Comment: 13 pages, 5 figure
Multi-scale interaction of flow and the artery wall
We discuss, from the perspective of basic science, the physical and biological processes which underlie atherosclerotic (plaque) initiation at the vascular endothelium, identifying their widely separated spatial and temporal scales which participate. We draw on current, related models of vessel wall evolution, paying particular attention to the role of flow, and proceed to propose, then validate (in practical, qualitative terms, at least) a multiply coupled, multi-scale modeling strategy, which, eventually, aims at a quantitative, patient-specific understanding of the coupling between the flow and the endothelial state
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