Significant carotid stenosis compromises hemodynamics and impairs cognitive functions. The interplay between these changes and brain connectivity has rarely been investigated. We aimed to discover the changes of functional connectivity and its relation to cognitive decline in carotid stenosis patients. Twenty-seven patients with unilateral carotid stenosis (≥60%) and 20 age- and sex-matched controls underwent neuropsychological tests and resting-state functional magnetic resonance imaging. The patients also received perfusion magnetic resonance imaging. The relationships between cognitive function and functional networks among the patients and controls were evaluated. Graph theory was applied on resting-state functional magnetic resonance imaging network analysis, which revealed that the hemispheres ipsilateral to the stenosis were significantly impaired in “degree” and “global efficiency.” The neuropsychological performances were positively correlated with degree, clustering coefficient, local efficiency, and global efficiency, and negatively correlated with characteristic path length, modularity, and small-worldness in the patients, whereas these relationships were not observed in the controls. In this study, we identified the networks that were impaired in the affected hemispheres in patients with carotid stenosis. Specific indices (global efficiency, characteristic path length, and modularity) were highly correlated with neuropsychological performance in our patients. Analysis of brain connectivity may help to elucidate the relationship between hemodynamic impairment and cognitive decline.
In adults with asthma, occupational exposure to high and low molecular weight asthmogens appears to produce differential risks for atopic and nonatopic asthma.
Nanodiscs
are broadly used for characterization of membrane proteins
as they are generally assumed to provide a near-native environment.
In fact, it is an open question whether the physical properties of
lipids in nanodiscs and membrane vesicles of the same lipid composition
are identical. Here, we investigate the properties of lipids (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, 1,2-dilauroyl-sn-glycero-3-phosphocholine, and their mixtures) in two different sample
types, nanodiscs and multilamellar vesicles, by means of spin-label
electron spin resonance techniques. Our results provide a quantitative
description of lipid dynamics and ordering, elucidating the molecular
details of how lipids in the two sample types behave differently in
response to temperature and lipid composition. We show that the properties
of lipids are altered in nanodiscs such that the dissimilarity of
the fluid and gel lipid phases is reduced, and the first-order phase
transitions are largely abolished in nanodiscs. We unveil that the
ensemble of lipids in the middle of a nanodisc bilayer, as probed
by the end-chain spin-label 16-PC, is promoted to a state close to
a miscibility critical point, thereby rendering the phase transitions
continuous. Critical phenomena have recently been proposed to explain
features of the heterogeneity in native cell membranes. Our results
lay the groundwork for how to establish a near-native environment
in nanodiscs with simple organization of lipid components.
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