548 research outputs found
The effects of gonadal hormones on the expression of the clock protein PER2 in the central extended amygdala
Most biological processes exhibit circadian rhythms that are synchronized by the master clock located in the suprachiasmatic nucleus (SCN). Recently, cells in the oval nucleus of the bed nucleus of the stria terminalis (OV-BNST), the central nucleus of the amygdala (CEA), basolateral amygdala (BLA) and dentate gyrus of the hippocampus (DG), have been shown to rhythmically express Period 2 (PER2), a clock protein. It is known that gonadal hormones have an effect on circadian rhythms. However, yet to be determined is what influence they might have on brain circadian oscillators outside of the SCN. The purpose of this series of experiments is to examine PER2 expression; firstly, in intact females over the course of the estrous cycle and, secondly, in gonadectomized females, males, and intact males. Results obtained from the intact females suggest that the pattern of PER2 expression in the OV-BNST and the CEA changes as a function of stage of the estrous cycle. In ovariectomized females peak PER2 expression in the OV-BNST and CEA is at ZT13, the same was also found in gonadectomized and intact males. Together, the data from these studies suggest that gonadal hormones may influence the circadian functioning of these two brain regions
Ketamine as the anaesthetic for electroconvulsive therapy:the KANECT randomised controlled trial
C.AS. reports grants from Vifor Pharma, outside the submitted work. I.C.R. (deceased) declared personal fees from AstraZeneca, Sanofi Aventis and Sunovion, and non-financial support from Lundbeck, between 2009 and 2014 and all outside the submitted work. Volume 212, Issue 5 May 2018 , p. 323 Ketamine as the anaesthetic for electroconvulsive therapy: the KANECT randomised controlled trial – CORRIGENDUM Gordon Fernie, James Currie, Jennifer S. Perrin, Caroline A. Stewart... https://doi.org/10.1192/bjp.2018.76 Published online: 06 April 2018 Summary: This notice describes a correction to the above mentioned paper.Peer reviewedPublisher PD
Growth of white matter in the adolescent brain: role of testosterone and androgen receptor
The growth of white matter during human adolescence shows a striking sexual dimorphism; the volume of white matter increases with age slightly in girls and steeply in boys. Here, we provide evidence supporting the role of androgen receptor (AR) in mediating the effect of testosterone on white matter. In a large sample of typically developing adolescents (n = 408, 204 males), we used magnetic resonance imaging and acquired T1-weighted and magnetization transfer ratio (MTR) images. We also measured plasma levels of testosterone and genotyped a functional polymorphism in the AR gene, namely the number of CAG repeats in exon 1 believed to be inversely proportional to the AR transcriptional activity. We found that the testosterone-related increase of white-matter volume was stronger in male adolescents with the lower versus higher number of CAG repeats in the AR gene, with testosterone explaining, respectively, 26 and 8% of variance in the volume. The MTR results suggest that this growth is not related to myelination; the MTR decreased with age in male adolescents. We speculate that testosterone affects axonal caliber rather than the thickness of the myelin sheath
O/IR Polarimetry for the 2010 Decade (GAN): Science at the Edge, Sharp Tools for All
Science opportunities and recommendations concerning optical/infrared
polarimetry for the upcoming decade in the field of Galactic science.
Community-based White Paper to Astro2010 in response to the call for such
papers.Comment: White Paper to the Galactic Neighborhood (GAN) Science Frontiers
Panel of the Astro2010 Decadal Surve
Discovery and characterization of artifactual mutations in deep coverage targeted capture sequencing data due to oxidative DNA damage during sample preparation
As researchers begin probing deep coverage sequencing data for increasingly rare mutations and subclonal events, the fidelity of next generation sequencing (NGS) laboratory methods will become increasingly critical. Although error rates for sequencing and polymerase chain reaction (PCR) are well documented, the effects that DNA extraction and other library preparation steps could have on downstream sequence integrity have not been thoroughly evaluated. Here, we describe the discovery of novel C > A/G > T transversion artifacts found at low allelic fractions in targeted capture data. Characteristics such as sequencer read orientation and presence in both tumor and normal samples strongly indicated a non-biological mechanism. We identified the source as oxidation of DNA during acoustic shearing in samples containing reactive contaminants from the extraction process. We show generation of 8-oxoguanine (8-oxoG) lesions during DNA shearing, present analysis tools to detect oxidation in sequencing data and suggest methods to reduce DNA oxidation through the introduction of antioxidants. Further, informatics methods are presented to confidently filter these artifacts from sequencing data sets. Though only seen in a low percentage of reads in affected samples, such artifacts could have profoundly deleterious effects on the ability to confidently call rare mutations, and eliminating other possible sources of artifacts should become a priority for the research community.National Human Genome Research Institute (U.S.) (HG03067-05
Quantifying regional α -synuclein, amyloid β, and tau accumulation in Lewy body dementia
OBJECTIVE: Parkinson disease (PD) is defined by the accumulation of misfolded α-synuclein (α-syn) in Lewy bodies and Lewy neurites. It affects multiple cortical and subcortical neuronal populations. The majority of people with PD develop dementia, which is associated with Lewy bodies in neocortex and referred to as Lewy body dementia (LBD). Other neuropathologic changes, including amyloid β (Aβ) and tau accumulation, occur in some LBD cases. We sought to quantify α-syn, Aβ, and tau accumulation in neocortical, limbic, and basal ganglia regions.
METHODS: We isolated insoluble protein from fresh frozen postmortem brain tissue samples for eight brains regions from 15 LBD, seven Alzheimer disease (AD), and six control cases. We measured insoluble α-syn, Aβ, and tau with recently developed sandwich ELISAs.
RESULTS: We detected a wide range of insoluble α-syn accumulation in LBD cases. The majority had substantial α-syn accumulation in most regions, and dementia severity correlated with neocortical α-syn. However, three cases had low neocortical levels that were indistinguishable from controls. Eight LBD cases had substantial Aβ accumulation, although the mean Aβ level in LBD was lower than in AD. The presence of Aβ was associated with greater α-syn accumulation. Tau accumulation accompanied Aβ in only one LBD case.
INTERPRETATION: LBD is associated with insoluble α-syn accumulation in neocortical regions, but the relatively low neocortical levels in some cases suggest that other changes contribute to impaired function, such as loss of neocortical innervation from subcortical regions. The correlation between Aβ and α-syn accumulation suggests a pathophysiologic relationship between these two processes
Automated data processing architecture for the Gemini Planet Imager Exoplanet Survey
The Gemini Planet Imager Exoplanet Survey (GPIES) is a multi-year direct
imaging survey of 600 stars to discover and characterize young Jovian
exoplanets and their environments. We have developed an automated data
architecture to process and index all data related to the survey uniformly. An
automated and flexible data processing framework, which we term the Data
Cruncher, combines multiple data reduction pipelines together to process all
spectroscopic, polarimetric, and calibration data taken with GPIES. With no
human intervention, fully reduced and calibrated data products are available
less than an hour after the data are taken to expedite follow-up on potential
objects of interest. The Data Cruncher can run on a supercomputer to reprocess
all GPIES data in a single day as improvements are made to our data reduction
pipelines. A backend MySQL database indexes all files, which are synced to the
cloud, and a front-end web server allows for easy browsing of all files
associated with GPIES. To help observers, quicklook displays show reduced data
as they are processed in real-time, and chatbots on Slack post observing
information as well as reduced data products. Together, the GPIES automated
data processing architecture reduces our workload, provides real-time data
reduction, optimizes our observing strategy, and maintains a homogeneously
reduced dataset to study planet occurrence and instrument performance.Comment: 21 pages, 3 figures, accepted in JATI
Characterizing 51 Eri b from 1-5 m: a partly-cloudy exoplanet
We present spectro-photometry spanning 1-5 m of 51 Eridani b, a 2-10
M planet discovered by the Gemini Planet Imager Exoplanet Survey.
In this study, we present new (1.90-2.19 m) and (2.10-2.40
m) spectra taken with the Gemini Planet Imager as well as an updated
(3.76 m) and new (4.67 m) photometry from the NIRC2 Narrow
camera. The new data were combined with (1.13-1.35 m) and
(1.50-1.80 m) spectra from the discovery epoch with the goal of better
characterizing the planet properties. 51 Eri b photometry is redder than field
brown dwarfs as well as known young T-dwarfs with similar spectral type
(between T4-T8) and we propose that 51 Eri b might be in the process of
undergoing the transition from L-type to T-type. We used two complementary
atmosphere model grids including either deep iron/silicate clouds or
sulfide/salt clouds in the photosphere, spanning a range of cloud properties,
including fully cloudy, cloud free and patchy/intermediate opacity clouds.
Model fits suggest that 51 Eri b has an effective temperature ranging between
605-737 K, a solar metallicity, a surface gravity of (g) = 3.5-4.0 dex,
and the atmosphere requires a patchy cloud atmosphere to model the SED. From
the model atmospheres, we infer a luminosity for the planet of -5.83 to -5.93
(), leaving 51 Eri b in the unique position as being one of
the only directly imaged planet consistent with having formed via cold-start
scenario. Comparisons of the planet SED against warm-start models indicates
that the planet luminosity is best reproduced by a planet formed via core
accretion with a core mass between 15 and 127 M.Comment: 27 pages, 19 figures, Accepted for publication in The Astronomical
Journa
GPI spectra of HR 8799 c, d, and e from 1.5 to 2.4m with KLIP Forward Modeling
We explore KLIP forward modeling spectral extraction on Gemini Planet Imager
coronagraphic data of HR 8799, using PyKLIP and show algorithm stability with
varying KLIP parameters. We report new and re-reduced spectrophotometry of HR
8799 c, d, and e in H & K bands. We discuss a strategy for choosing optimal
KLIP PSF subtraction parameters by injecting simulated sources and recovering
them over a range of parameters. The K1/K2 spectra for HR 8799 c and d are
similar to previously published results from the same dataset. We also present
a K band spectrum of HR 8799 e for the first time and show that our H-band
spectra agree well with previously published spectra from the VLT/SPHERE
instrument. We show that HR 8799 c and d show significant differences in their
H & K spectra, but do not find any conclusive differences between d and e or c
and e, likely due to large error bars in the recovered spectrum of e. Compared
to M, L, and T-type field brown dwarfs, all three planets are most consistent
with mid and late L spectral types. All objects are consistent with low gravity
but a lack of standard spectra for low gravity limit the ability to fit the
best spectral type. We discuss how dedicated modeling efforts can better fit HR
8799 planets' near-IR flux and discuss how differences between the properties
of these planets can be further explored.Comment: Accepted to AJ, 25 pages, 16 Figure
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