1,950 research outputs found
A spatial covariance (123)I-5IA-85380 SPECT study of α4β2 nicotinic receptors in Alzheimer's disease
Alzheimer's disease (AD) is characterized by widespread degeneration of cholinergic neurons, particularly in the basal forebrain. However, the pattern of these deficits and relationship with known brain networks is unknown. In this study, we sought to clarify this and used 123I-5-iodo-3-[2(S)-2-azetidinylmethoxy] pyridine (1235IA-85380) single photon emission computed tomography to investigate spatial covariance of α4β2 nicotinic acetylcholine receptors in AD and healthy controls. Thirteen AD and 16 controls underwent 1235IA-85380 and regional cerebral blood flow (99mTc-exametazime) single photon emission computed tomography scanning. We applied voxel principal component (PC) analysis, generating series of principal component images representing common intercorrelated voxels across subjects. Linear regression generated specific α4β2 and regional cerebral blood flow covariance patterns that differentiated AD from controls. The α4β2 pattern showed relative decreased uptake in numerous brain regions implicating several networks including default mode, salience, and Papez hubs. Thus, as well as basal forebrain and brainstem cholinergic system dysfunction, cholinergic deficits mediated through nicotinic acetylcholine receptors could be evident within key networks in AD. These findings may be important for the pathophysiology of AD and its associated cognitive and behavioral phenotypes
Improved Efficacy of a Gene Optimised Adenovirus-based Vaccine for Venezuelan Equine Encephalitis Virus
<p>Abstract</p> <p>Background</p> <p>Optimisation of genes has been shown to be beneficial for expression of proteins in a range of applications. Optimisation has increased protein expression levels through improved codon usage of the genes and an increase in levels of messenger RNA. We have applied this to an adenovirus (ad)-based vaccine encoding structural proteins (E3-E2-6K) of Venezuelan equine encephalitis virus (VEEV).</p> <p>Results</p> <p>Following administration of this vaccine to Balb/c mice, an approximately ten-fold increase in antibody response was elicited and increased protective efficacy compared to an ad-based vaccine containing non-optimised genes was observed after challenge.</p> <p>Conclusion</p> <p>This study, in which the utility of optimising genes encoding the structural proteins of VEEV is demonstrated for the first time, informs us that including optimised genes in gene-based vaccines for VEEV is essential to obtain maximum immunogenicity and protective efficacy.</p
Esterification Prevents Induction of the Mitochondrial Permeability Transition by N-Acetyl Perfluorooctane Sulfonamides
N-Alkyl perfluorooctane sulfonamides have been widely used as surfactants on fabrics and papers, fire retardants, and anticorrosion agents, among many other commercial applications. The broad use, global distribution, and environmental persistence of these compounds has generated considerable interest regarding potentially toxic effects. We have previously reported that perfluorooctanesulfonamidoacetate (FOSAA) and N-ethylperfluorooctanesulfonamidoacetate (N-EtFOSAA) induce the mitochondrial permeability transition (MPT) in vitro, resulting in cytochrome c release, inhibition of respiration, and generation of reactive oxygen species. By synthesizing the corresponding methyl esters of FOSAA and N-EtFOSAA (methyl perlfuorinated sulfonamide acetates), we tested the hypothesis that the N-acetate moiety of FOSAA and N-EtFOSAA is the functional group responsible for induction of the MPT. Swelling of freshly isolated liver mitochondria from Sprague−Dawley rats was monitored spectrophotometrically and membrane potential (ΔΨ) was measured using a tetraphenylphosphonium-selective (TPP+) electrode. In the presence of calcium, 40 μM FOSAA and 7 μM N-EtFOSAA each induced mitochondrial swelling and a biphasic depolarization of membrane potential. Mitochondrial swelling and the second-phase depolarization were inhibited by cyclosporin-A or the catalyst of K+/H+ exchange nigericin, whereas the first-phase depolarization was not affected by either. In contrast, the methyl esters of FOSAA and N-EtFOSAA exhibited no depolarizing or MPT inducing activity. Results of this investigation demonstrate that the carboxylic acid moiety of the N-acetates is the active functional group, which triggers the MPT by perfluorinated sulfonamides
Water Markets: Australia's Murray-Darling Basin and the US Southwest
Fresh water supplies increasingly are under stress in many parts of the world due to rising populations, higher per capita incomes and corresponding consumption, greater environmental concerns, and the effects of climate change. Water rights and markets are part of the institutional menus for responding to these problems. We examine water markets in both Australia’s MDB and the western US and their prospects for addressing water scarcity. The two regions share a number of important similarities including: climate variability that requires investment in reservoirs to make water available in low-rainfall periods; the need for internal and cross-border (state) water management; an historical major allocation of water to irrigators; increasing competition among different uses (agricultural, environmental and recreational in situ uses, urban demand); and the potential for water trading to more smoothly and quickly allocate water across these competing uses. A comparison of the two regions provides important insights about how economic factors can encourage more efficient water allocation, market structure and government regulation. We show that rights are more clearly defined and trading more common in Australia than appears to be the case in the western U.S. Longer periods of scarcity and hence, higher water values may explain this difference.
Public and Private Spheres of Neighborhood Disorder: Assessing Pathways to Violence Using Large-scale Digital Records
Objectives: “Broken windows” theory is an influential model of neighborhood change, but there is disagreement over whether public disorder leads to more serious crime. This article distinguishes between public and private disorder, arguing that large-scale administrative data provide new opportunities to examine broken windows theory and alternative models of neighborhood change.
Method: We apply an ecometric methodology to two databases from Boston: 1,000,000+ 911 dispatches and indicators of physical disorder from 200,000+ requests for nonemergency services. Both distinguish between disorder in public and private spaces. A cross-lag longitudinal analysis was conducted using two full years of data (2011–2012).
Results: The two databases provided six dimensions of physical and social disorder and crime. The cross-lag model revealed eight pathways by which one form of disorder or crime in 2011 predicted a significant increase in another in 2012. Although traditional interpretations of broken windows emphasize the role of public disorder, private conflict most strongly predicted future crime.
Conclusions: Our results describe a social escalation model where future disorder and crime emerge not from public cues but from private disorder within the community, demonstrating how “big data” from administrative records, when properly measured and interpreted, represent a growing resource for studying neighborhood change.Sociolog
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