340 research outputs found
Healing patterns of choroidal tubercles after antitubercular therapy: A photographic and OCT study
A 28-year-old female patient with disseminated tuberculosis and choroidal tubercles on a regimen of systemic antitubercular therapy underwent fundus photography and optical coherence tomography (OCT). This was carried out monthly until complete healing of the tubercle was seen. The tubercle consisted of a central white-yellow core, consistent with choroiditis, with a faint hyperpigmentation surrounding it. There was a surrounding diffuse rim of inflammation. By the second month, the hyperpigmented rim was more prominent as were the outer edges of both the central core and the outer rim. Over time, the outer rim had largely faded with concurrent scar formation in the core. The initial OCT analysis revealed a raised RPE-choriocapillaris complex. With healing, there was a marked reduction in the choroidal lesional height suggesting resolution
Elevated 5hmC levels characterize DNA of the cerebellum in Parkinson’s disease
5-methylcytosine and the oxidation product 5-hydroxymethylcytosine are two prominent epigenetic variants of the cytosine base in nuclear DNA of mammalian brains. We measured levels of 5-methylcytosine and 5-hydroxymethylcytosine by enzyme-linked immunosorbent assay in DNA from post-mortem cerebella of individuals with Parkinson’s disease and age-matched controls. 5-methylcytosine levels showed no significant differences between Parkinson’s disease and control DNA sample sets. In contrast, median 5-hydroxymethylcytosine levels were almost twice as high (p < 0.001) in both male and female Parkinson’s disease individuals compared with controls. The distinct epigenetic profile identified in cerebellar DNA of Parkinson’s disease patients raises the question whether elevated 5-hydroxymethylcytosine levels are a driver or a consequence of Parkinson’s disease
z ∼ 2–9 Galaxies Magnified by the Hubble Frontier Field Clusters. II. Luminosity Functions and Constraints on a Faint-end Turnover
We present new determinations of the rest-UV luminosity functions (LFs) at z = 2–9 to extremely low luminosities (>−14 mag) from a sample of >2500 lensed galaxies found behind the Hubble Frontier Fields (HFF) clusters. For the first time, we present faint-end slope results from lensed samples that are fully consistent with blank-field results over the redshift range z = 2–9, while reaching to much lower luminosities than possible from the blank-field studies. Combining the deep lensed sample with the large blank-field samples allows us to set tight constraints on the faint-end slope α of the z = 2–9 UV LFs and its evolution. We find a smooth flattening in α from −2.28 ± 0.10 (z = 9) to −1.53 ± 0.03 (z = 2) with cosmic time (dα/dz = −0.11 ± 0.01), fully consistent with dark matter halo buildup. We utilize these new results to present new measurements of the evolution in the UV luminosity density ρ
UV
brighter than −13 mag from z ∼ 9 to z ∼ 2. Accounting for the star formation rate (SFR) densities to faint luminosities implied by our LF results, we find that unobscured star formation dominates the SFR density at z ≳ 4, with obscured star formation dominant thereafter. Having shown we can quantify the faint-end slope α of the LF accurately with our lensed HFF samples, we also quantify the apparent curvature in the shape of the UV LF through a curvature parameter δ. The constraints on the curvature δ strongly rule out the presence of a turn-over brighter than −13.1 mag at z ∼ 3, −14.3 mag at z ∼ 6, and −15.5 mag at all other redshifts between z ∼ 9 and z ∼ 2
Genome-wide DNA methylation map of human neutrophils reveals widespread inter-individual epigenetic variation
The extent of variation in DNA methylation patterns in healthy individuals is not yet well documented. Identification of inter-individual epigenetic variation is important for understanding phenotypic variation and disease susceptibility. Using neutrophils from a cohort of healthy individuals, we generated base-resolution DNA methylation maps to document inter-individual epigenetic variation. We identified 12851 autosomal inter-individual variably methylated fragments (iVMFs). Gene promoters were the least variable, whereas gene body and upstream regions showed higher variation in DNA methylation. The iVMFs were relatively enriched in repetitive elements compared to non-iVMFs, and were associated with genome regulation and chromatin function elements. Further, variably methylated genes were disproportionately associated with regulation of transcription, responsive function and signal transduction pathways. Transcriptome analysis indicates that iVMF methylation at differentially expressed exons has a positive correlation and local effect on the inclusion of that exon in the mRNA transcript
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An Ultra Deep Field survey with WFIRST
Studying the formation and evolution of galaxies at the earliest cosmic
times, and their role in reionization, requires the deepest imaging possible.
Ultra-deep surveys like the HUDF and HFF have pushed to mag \mAB30,
revealing galaxies at the faint end of the LF to 911 and
constraining their role in reionization. However, a key limitation of these
fields is their size, only a few arcminutes (less than a Mpc at these
redshifts), too small to probe large-scale environments or clustering
properties of these galaxies, crucial for advancing our understanding of
reionization. Achieving HUDF-quality depth over areas 100 times larger
becomes possible with a mission like the Wide Field Infrared Survey Telescope
(WFIRST), a 2.4-m telescope with similar optical properties to HST, with a
field of view of 1000 arcmin, 100 the area of the
HST/ACS HUDF.
This whitepaper motivates an Ultra-Deep Field survey with WFIRST, covering
100300 the area of the HUDF, or up to 1 deg, to
\mAB30, potentially revealing thousands of galaxies and AGN at the
faint end of the LF, at or beyond \,\,910 in the epoch of
reionization, and tracing their LSS environments, dramatically increasing the
discovery potential at these redshifts.
(Note: This paper is a somewhat expanded version of one that was submitted as
input to the Astro2020 Decadal Survey, with this version including an Appendix
(which exceeded the Astro2020 page limits), describing how the science drivers
for a WFIRST Ultra Deep Field might map into a notional observing program,
including the filters used and exposure times needed to achieve these depths.
Highly efficient PCR assay to discriminate allelic DNA methylation status using whole genome amplification
<p>Abstract</p> <p>Background</p> <p>We previously developed a simple method termed <it>Hpa</it>II-<it>McrBC </it>PCR (HM-PCR) to discriminate allelic methylation status of the genomic sites of interest, and successfully applied it to a comprehensive analysis of CpG islands (CGIs) on human chromosome 21q. However, HM-PCR requires 200 ng of genomic DNA to examine one target site, thereby precluding its application to such samples that are limited in quantity.</p> <p>Findings</p> <p>We developed <it>Hpa</it>II-<it>McrBC </it>whole-genome-amplification PCR (HM-WGA-PCR) that uses whole-genome-amplified DNA as the template. HM-WGA-PCR uses only 1/100th the genomic template material required for HM-PCR. Indeed, we successfully analyzed 147 CGIs by HM-WGA-PCR using only ~300 ng of DNA, whereas previous HM-PCR study had required ~30 μg. Furthermore, we confirmed that allelic methylation status revealed by HM-WGA-PCR is identical to that by HM-PCR in every case of the 147 CGIs tested, proving high consistency between the two methods.</p> <p>Conclusions</p> <p>HM-WGA-PCR would serve as a reliable alternative to HM-PCR in the analysis of allelic methylation status when the quantity of DNA available is limited.</p
Immunostaining of modified histones defines high-level features of the human metaphase epigenome
Background: Immunolabeling of metaphase chromosome spreads can map components of the human epigenome at the single cell level. Previously, there has been no systematic attempt to explore the potential of this approach for epigenomic mapping and thereby to complement approaches based on chromatin immunoprecipitation (ChIP) and sequencing technologies.Results: By immunostaining and immunofluorescence microscopy, we have defined the distribution of selected histone modifications across metaphase chromosomes from normal human lymphoblastoid cells and constructed immunostained karyotypes. Histone modifications H3K9ac, H3K27ac and H3K4me3 are all located in the same set of sharply defined immunofluorescent bands, corresponding to 10- to 50-Mb genomic segments. Primary fibroblasts gave broadly the same banding pattern. Bands co-localize with regions relatively rich in genes and CpG islands. Staining intensity usually correlates with gene/CpG island content, but occasional exceptions suggest that other factors, such as transcription or SINE density, also contribute. H3K27me3, a mark associated with gene silencing, defines a set of bands that only occasionally overlap with gene-rich regions. Comparison of metaphase bands with histone modification levels across the interphase genome (ENCODE, ChIP-seq) shows a close correspondence for H3K4me3 and H3K27ac, but major differences for H3K27me3.Conclusions: At metaphase the human genome is packaged as chromatin in which combinations of histone modifications distinguish distinct regions along the euchromatic chromosome arms. These regions reflect the high-level interphase distributions of some histone modifications, and may be involved in heritability of epigenetic states, but we also find evidence for extensive remodeling of the epigenome at mitosis.</p
Self-medication for infants with colic in Lagos, Nigeria
<p>Abstract</p> <p>Background</p> <p>Infantile colic is a self-limiting condition that is distributed worldwide. It is often misdiagnosed as an organic disease for which an infant is admitted to the hospital. Many studies have described the aetiopathogenesis, pharmacologic and non-pharmacologic management of colic but none has evaluated self-medication for infants with colic. The aim of this study was therefore to determine the knowledge of Nigerian mothers about colic, their home-based management, extent of self-medication for the infants with colic and the types of medicines involved.</p> <p>Methods</p> <p>It is a prospective study conducted at the vaccination clinics of 20 primary health care centres, each from different Local Government Areas in Lagos, Nigeria. Eight hundred mothers that brought their infants for vaccination between April and September, 2006 were interviewed with open-and close-ended questionnaire.</p> <p>Results</p> <p>Six hundred and eighty three (85.4%) mothers claimed they had a good knowledge of colic. Incessant and excessive cry was the main clinical feature of colic identified by 430(62.9%) mothers. Three hundred and seventy eight (67.7%) infants were treated by self-medication, 157 (28.1%) sought medical intervention and 17 (3.1%) were treated at a traditional birth attendant home. Herbal medicines constituted 51.8% of the self-medicated medicines, of which 48 (26.2%) were "Ororo Ogiri". Nospamin<sup>® </sup>(49.5%) and Gripe water<sup>® </sup>(43.0%) were the two frequently prescribed and self-medicated medicines for infants with colic.</p> <p>Conclusion</p> <p>Nigerian mothers are deficient in their knowledge of colic. Self-medication was the most frequently used home-based intervention. Health education would appear necessary to improve parental management of this self-limiting condition.</p
Rapid Evolution in the Most Luminous Galaxies During the First 900 Million Years
The first 900 million years (Myr) to redshift z~6 (the first seven per cent
of the age of the Universe) remains largely unexplored for the formation of
galaxies. Large samples of galaxies have been found at z~6, but detections at
earlier times are uncertain and unreliable. It is not at all clear how galaxies
built up from the first stars when the Universe was ~300 Myr old (z~12-15) to
z~6, just 600 Myr later. Here we report the results of a search for galaxies at
z~7-8, about 700 Myr after the Big Bang, using the deepest near-infrared and
optical images ever taken. Under conservative selection criteria we find only
one candidate galaxy at z~7-8, where ten would be expected if there were no
evolution in the galaxy population between z~7-8 and z~6. Using less
conservative criteria, there are four candidates, where 17 would be expected
with no evolution. This demonstrates that very luminous galaxies are quite rare
700 Myr after the Big Bang. The simplest explanation is that the Universe is
just too young to have built up many luminous galaxies at z~7-8 by the
hierarchical merging of small galaxies.Comment: Accepted for publication in Nature, 20 pages, 5 figures, 2 tables
(includes Supplementary Information), replaced to match version in pres
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