1,287 research outputs found
Mutation-Independent Allele-Specific Editing by CRISPR-Cas9, a Novel Approach to Treat Autosomal Dominant Disease
CRISPR-Cas9 provides a tool to treat autosomal dominant disease by non-homologous end joining (NHEJ) gene disruption of the mutant allele. In order to discriminate between wild-type and mutant alleles, Streptococcus pyogenes Cas9 (SpCas9) must be able to detect a single nucleotide change. Allele-specific editing can be achieved by using either a guide-specific approach, in which the missense mutation is found within the guide sequence, or a protospacer-adjacent motif (PAM)-specific approach, in which the missense mutation generates a novel PAM. While both approaches have been shown to offer allele specificity in certain contexts, in cases where numerous missense mutations are associated with a particular disease, such as TGFBI (transforming growth factor Ī²-induced) corneal dystrophies, it is neither possible nor realistic to target each mutation individually. In this study, we demonstrate allele-specific CRISPR gene editing independent of the disease-causing mutation that is capable of achieving complete allele discrimination, and we propose it as a targeting approach for autosomal dominant disease. Our approach utilizes natural variants in the target region that contain a PAM on one allele that lies in cis with the causative mutation, removing the constraints of a mutation-dependent approach. Our innovative patient-specific guide design approach takes into account the patientās individual genetic make-up, allowing on- and off-target activity to be assessed in a personalized manner
Consensus-based statements for the management of mitochondrial stroke-like episodes [version 1; peer review: 2 approved]
BACKGROUND: Focal-onset seizures and encephalopathy are prominent features of a stroke-like episode, which is a severe neurological manifestation associated with subtypes of mitochondrial disease. Despite more than 30 years of research, the acute treatment of stroke-like episodes remains controversial. METHODS: We used the modified Delphi process to harness the clinical expertise of a group of mitochondrial disease specialists from five European countries to produce consensus guidance for the acute management of stroke-like episodes and commonly associated complications. RESULTS: Consensus on a new definition of mitochondrial stroke-like episodes was achieved and enabled the group to develop diagnostic criteria based on clinical features, neuroimaging and/or electroencephalogram findings. Guidelines for the management of strokelike episodes were agreed with aggressive seizure management strongly recommended at the outset of stroke-like episodes. CONCLUSIONS: Our consensus statement defines stroke-like episodes in terms of an epileptic encephalopathy and we have used this to revise both diagnostic criteria and guidelines for management. A prospective, multi-centre, randomised controlled trial is required for evaluating the efficacy of any compound on modifying the trajectory of stroke-like episodes
The spatial distribution and origin of the FUV excess in early-type galaxies
We present surface photometry of a sample of 52 galaxies from the GALEX and
2MASS data archives, these include 32 normal elliptical galaxies, 10
ellipticals with weak Liner or other nuclear activity, and 10 star forming
ellipticals or early-type spirals. We examine the spatial distribution of the
Far Ultra-Violet excess in these galaxies, and its correlation with dynamical
and stellar population properties of the galaxies. From aperture photometry we
find that all galaxies except for recent major remnants and galaxies with
ongoing star formation show a positive gradient in the (FUV-NUV) colour
determined from the GALEX images. The logarithmic gradient does not correlate
with any stellar population parameter, but it does correlate with the central
velocity dispersion. The strength of the excess on the other hand, correlates
with both [alpha/Fe] and [Z/H], but more strongly with the former. We derive
models of the underlying stellar population from the 2MASS H-band images, and
the residual of the image from this model reveals a map of the centrally
concentrated FUV excess. We examine a possible hypothesis for generating the
FUV excess and the radial gradient in its strength, involving a helium
abundance gradient set up early in the formation process of the galaxies. If
this hypothesis is correct, the persistence of the gradients to the present day
places a strong limit on the importance of dry mergers in the formation of
ellipticals.Comment: 36 pages, accepted for publication in MNRAS. Appendices will appear
in online journal only. This version has reduced resolution for the figure in
Appendix B to comply with arXiv size limit
A new governance approach for multi-firm projects: lessons from Olkiluoto 3 and Flamanville 3 nuclear power plant projects
We analyze governance in two contemporary nuclear power plant projects: Olkiluoto 3 (Finland) and Flamanville 3 (France). We suggest that in the governance of large multi-firm projects, any of the prevalent governance approaches that rely on market, hierarchy, or hybrid forms, is not adequate as such. This paper opens up avenues towards a novel theory of governance in large projects by adopting a project network view with multiple networked firms within a single project, and by simultaneously going beyond organizational forms that cut across the traditional firmāmarket dichotomy. Our analysis suggests four changes in the prevailing perspective towards the governance of large projects. First, there should be a shift from viewing multi-firm projects as hierarchical contract organizations to viewing them as supply networks characterized by a complex and networked organizational structure. Second, there should be a shift in the emphasis of the predominant modes of governance, market and hierarchy towards novel governance approaches that emphasize network-level mechanisms such as self-regulation within the project. Third, there should be a shift from viewing projects as temporary endeavors to viewing projects as short-term events or episodes embedded in the long-term sphere of shared history and expected future activities among the involved actors. Fourth, there should be a shift from the prevailing narrow view of a hierarchical project management system towards an open system view of managing in complex and challenging institutional environments
Glyconanoparticles for colorimetric bioassays
Carbohydrate molecules are involved in many of the cellular processes that are important for life. By combining the specific analyte targeting of carbohydrates with the multivalent structure and change of solution colour as a consequence of plasmonic interactions with the aggregation of metal nanoparticles, glyconanoparticles have been used extensively for the development of bioanalytical assays. The noble metals used to create the nanocore, the methodologies used to assemble the carbohydrates on the nanoparticle surface, the carbohydrate chosen for each specific target, the length of the tether that separates the carbohydrate from the nanocore and the density of carbohydrates on the surface all impact on the structural formation of metal based glyconanoparticles. This tutorial review highlights these key components, which directly impact on the selectivity and sensitivity of the developed bioassay, for the colorimetric detection of lectins, toxins and viruses
Ontogeny of feeding performance and biomechanics in coyotes
Developing organisms must reconcile conflicts between demands of survival within the current lifeāhistory stage, with those of maturation, while negotiating the transitions through succeeding stages. In the case of feeding performance, the parts of the feeding apparatus and their biomechanics must maintain functional integrity to meet the feeding needs of a juvenile even as they develop toward their adult form. We concurrently examine the ontogenetic relationships of feeding performance, dentition and feeding biomechanics, relative to key lifeāhistory events, utilizing samples drawn from the same population of knownāage coyotes Canis latrans . The development of feeding performance is asynchronous with development of both feeding biomechanics and skull morphology; feeding performance lags during ontogeny despite surprisingly large early mechanical advantage of the temporalis, due in part, to early relative maturity of mandibular shape. Feeding performance and biomechanics, like skull morphology, mature well after weaning at 6āweeks of age. Late maturation of bite strength and feeding performance is mediated by ongoing and continued growth of the temporalis muscles as measured by maximum zygomatic arch breadth (ZAB). Males and females may resolve developmental conflicts differently, as females trade earlier maturity for smaller maximum ZAB, decreased relative bite strength and diminished feeding performance, compared with males. The asynchrony of feeding performance development seen in coyotes, is also characteristic of a highly specialized carnivore, the spotted hyena, but coyotes have a much less protracted development, being handicapped relative to adults for a much shorter time. This developmental asynchrony between feeding performance and morphology suggests that a certain minimum threshold of physical growth and development, together with the associated development of biomechanics, are required to produce effective mastication. The relationships among biomechanics, lifeāhistory schedules and ontogeny of feeding performance have obvious implications for fitness.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88048/1/jzo847.pd
Evaluating the Quality of Research into a Single Prognostic Biomarker: A Systematic Review and Meta-analysis of 83 Studies of C-Reactive Protein in Stable Coronary Artery Disease
Background
Systematic evaluations of the quality of research on a single prognostic biomarker are rare. We sought to evaluate the quality of prognostic research evidence for the association of C-reactive protein (CRP) with fatal and nonfatal events among patients with stable coronary disease.
Methods and Findings
We searched MEDLINE (1966 to 2009) and EMBASE (1980 to 2009) and selected prospective studies of patients with stable coronary disease, reporting a relative risk for the association of CRP with death and nonfatal cardiovascular events. We included 83 studies, reporting 61,684 patients and 6,485 outcome events. No study reported a prespecified statistical analysis protocol; only two studies reported the time elapsed (in months or years) between initial presentation of symptomatic coronary disease and inclusion in the study. Studies reported a median of seven items (of 17) from the REMARK reporting guidelines, with no evidence of change over time.
The pooled relative risk for the top versus bottom third of CRP distribution was 1.97 (95% confidence interval [CI] 1.78ā2.17), with substantial heterogeneity (I2 = 79.5). Only 13 studies adjusted for conventional risk factors (age, sex, smoking, obesity, diabetes, and low-density lipoprotein [LDL] cholesterol) and these had a relative risk of 1.65 (95% CI 1.39ā1.96), I2 = 33.7. Studies reported ten different ways of comparing CRP values, with weaker relative risks for those based on continuous measures. Adjusting for publication bias (for which there was strong evidence, Egger's p<0.001) using a validated method reduced the relative risk to 1.19 (95% CI 1.13ā1.25). Only two studies reported a measure of discrimination (c-statistic). In 20 studies the detection rate for subsequent events could be calculated and was 31% for a 10% false positive rate, and the calculated pooled c-statistic was 0.61 (0.57ā0.66).
Conclusion
Multiple types of reporting bias, and publication bias, make the magnitude of any independent association between CRP and prognosis among patients with stable coronary disease sufficiently uncertain that no clinical practice recommendations can be made. Publication of prespecified statistical analytic protocols and prospective registration of studies, among other measures, might help improve the quality of prognostic biomarker research
The ATLAS3D project - XXIX : The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images
Date of Acceptance: 25/09/2014Galactic archaeology based on star counts is instrumental to reconstruct the past mass assembly of Local Group galaxies. The development of new observing techniques and data reduction, coupled with the use of sensitive large field of view cameras, now allows us to pursue this technique in more distant galaxies exploiting their diffuse low surface brightness (LSB) light. As part of the ATLAS3D project, we have obtained with the MegaCam camera at the Canada-France-Hawaii Telescope extremely deep, multiband images of nearby early-type galaxies (ETGs). We present here a catalogue of 92 galaxies from the ATLAS3D sample, which are located in low- to medium-density environments. The observing strategy and data reduction pipeline, which achieve a gain of several magnitudes in the limiting surface brightness with respect to classical imaging surveys, are presented. The size and depth of the survey are compared to other recent deep imaging projects. The paper highlights the capability of LSB-optimized surveys at detecting new prominent structures that change the apparent morphology of galaxies. The intrinsic limitations of deep imaging observations are also discussed, among those, the contamination of the stellar haloes of galaxies by extended ghost reflections, and the cirrus emission from Galactic dust. The detection and systematic census of fine structures that trace the present and past mass assembly of ETGs are one of the prime goals of the project. We provide specific examples of each type of observed structures - tidal tails, stellar streams and shells - and explain how they were identified and classified. We give an overview of the initial results. The detailed statistical analysis will be presented in future papers.Peer reviewedFinal Accepted Versio
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