930 research outputs found
Characterization of Three-Dimensional Retinal Tissue Derived from Human Embryonic Stem Cells in Adherent Monolayer Cultures
Stem cell-based therapy of retinal degenerative conditions is a promising modality to treat blindness, but requires new strategies to improve the number of functionally integrating cells. Grafting semidifferentiated retinal tissue rather than progenitors allows preservation of tissue structure and connectivity in retinal grafts, mandatory for vision restoration. Using human embryonic stem cells (hESCs), we derived retinal tissue growing in adherent conditions consisting of conjoined neural retina and retinal pigment epithelial (RPE) cells and evaluated cell fate determination and maturation in this tissue. We found that deriving such tissue in adherent conditions robustly induces all eye field genes (RX, PAX6, LHX2, SIX3, SIX6) and produces four layers of pure populations of retinal cells: RPE (expressing NHERF1, EZRIN, RPE65, DCT, TYR, TYRP, MITF, PMEL), early photoreceptors (PRs) (coexpressing CRX and RCVRN), inner nuclear layer neurons (expressing CALB2), and retinal ganglion cells [RGCs, expressing BRN3B and Neurofilament (NF) 200]. Furthermore, we found that retinal progenitors divide at the apical side of the hESC-derived retinal tissue (next to the RPE layer) and then migrate toward the basal side, similar to that found during embryonic retinogenesis. We detected synaptogenesis in hESC-derived retinal tissue, and found neurons containing many synaptophysin-positive boutons within the RGC and PR layers. We also observed long NF200-positive axons projected by RGCs toward the apical side. Whole-cell recordings demonstrated that putative amacrine and/or ganglion cells exhibited electrophysiological responses reminiscent of those in normal retinal neurons. These responses included voltage-gated Na+ and K+ currents, depolarization-induced spiking, and responses to neurotransmitter receptor agonists. Differentiation in adherent conditions allows generation of long and flexible pieces of 3D retinal tissue suitable for isolating transplantable slices of tissue for retinal replacement therapies.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140208/1/scd.2015.0144.pd
Driven interfaces in disordered media: determination of universality classes from experimental data
While there have been important theoretical advances in understanding the
universality classes of interfaces moving in porous media, the developed tools
cannot be directly applied to experiments. Here we introduce a method that can
identify the universality class from snapshots of the interface profile. We
test the method on discrete models whose universality class is well known, and
use it to identify the universality class of interfaces obtained in experiments
on fluid flow in porous media.Comment: 4 pages, 5 figure
Model for End‐Stage Liver Disease‐Lactate and Prediction of Inpatient Mortality in Patients With Chronic Liver Disease
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163652/3/hep31199.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163652/2/hep31199_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163652/1/hep31199-sup-0001-Supinfo.pd
Isotopes of nitrogen on Mars: Atmospheric measurements by Curiosity's mass spectrometer
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102173/1/wong_readme.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102173/2/wong2013_SM_v4b.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102173/3/grl51166.pd
Telomeric expression sites are highly conserved in trypanosoma brucei
Subtelomeric regions are often under-represented in genome sequences of eukaryotes. One of the best known examples of the use of telomere proximity for adaptive purposes are the bloodstream expression sites (BESs) of the African trypanosome Trypanosoma brucei. To enhance our understanding of BES structure and function in host adaptation and immune evasion, the BES repertoire from the Lister 427 strain of T. brucei were independently tagged and sequenced. BESs are polymorphic in size and structure but reveal a surprisingly conserved architecture in the context of extensive recombination. Very small BESs do exist and many functioning BESs do not contain the full complement of expression site associated genes (ESAGs). The consequences of duplicated or missing ESAGs, including ESAG9, a newly named ESAG12, and additional variant surface glycoprotein genes (VSGs) were evaluated by functional assays after BESs were tagged with a drug-resistance gene. Phylogenetic analysis of constituent ESAG families suggests that BESs are sequence mosaics and that extensive recombination has shaped the evolution of the BES repertoire. This work opens important perspectives in understanding the molecular mechanisms of antigenic variation, a widely used strategy for immune evasion in pathogens, and telomere biology
Recommended from our members
HDAC9 is implicated in atherosclerotic aortic calcification and affects vascular smooth muscle cell phenotype.
Aortic calcification is an important independent predictor of future cardiovascular events. We performed a genome-wide association meta-analysis to determine SNPs associated with the extent of abdominal aortic calcification (n = 9,417) or descending thoracic aortic calcification (n = 8,422). Two genetic loci, HDAC9 and RAP1GAP, were associated with abdominal aortic calcification at a genome-wide level (P < 5.0 × 10-8). No SNPs were associated with thoracic aortic calcification at the genome-wide threshold. Increased expression of HDAC9 in human aortic smooth muscle cells promoted calcification and reduced contractility, while inhibition of HDAC9 in human aortic smooth muscle cells inhibited calcification and enhanced cell contractility. In matrix Gla protein-deficient mice, a model of human vascular calcification, mice lacking HDAC9 had a 40% reduction in aortic calcification and improved survival. This translational genomic study identifies the first genetic risk locus associated with calcification of the abdominal aorta and describes a previously unknown role for HDAC9 in the development of vascular calcification
NMR metabolomics of cerebrospinal fluid differentiates inflammatory diseases of the central nervous system
BACKGROUND:
Myriad infectious and noninfectious causes of encephalomyelitis (EM) have similar clinical manifestations, presenting serious challenges to diagnosis and treatment. Metabolomics of cerebrospinal fluid (CSF) was explored as a method of differentiating among neurological diseases causing EM using a single CSF sample.
METHODOLOGY/PRINCIPAL FINDINGS:
1H NMR metabolomics was applied to CSF samples from 27 patients with a laboratory-confirmed disease, including Lyme disease or West Nile Virus meningoencephalitis, multiple sclerosis, rabies, or Histoplasma meningitis, and 25 controls. Cluster analyses distinguished samples by infection status and moderately by pathogen, with shared and differentiating metabolite patterns observed among diseases. CART analysis predicted infection status with 100% sensitivity and 93% specificity.
CONCLUSIONS/SIGNIFICANCE:
These preliminary results suggest the potential utility of CSF metabolomics as a rapid screening test to enhance diagnostic accuracies and improve patient outcomes
Radio galaxy zoo EMU: towards a semantic radio galaxy morphology taxonomy
© 2023 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/)We present a novel natural language processing (NLP) approach to deriving plain English descriptors for science cases otherwise restricted by obfuscating technical terminology. We address the limitations of common radio galaxy morphology classifications by applying this approach. We experimentally derive a set of semantic tags for the Radio Galaxy Zoo EMU (Evolutionary Map of the Universe) project and the wider astronomical community. We collect 8486 plain English annotations of radio galaxy morphology, from which we derive a taxonomy of tags. The tags are plain English. The result is an extensible framework, which is more flexible, more easily communicated, and more sensitive to rare feature combinations, which are indescribable using the current framework of radio astronomy classifications.Peer reviewe
Effective DNA/RNA Co-Extraction for Analysis of MicroRNAs, mRNAs, and Genomic DNA from Formalin-Fixed Paraffin-Embedded Specimens
Background: Retrospective studies of archived human specimens, with known clinical follow-up, are used to identify predictive and prognostic molecular markers of disease. Due to biochemical differences, however, formalin-fixed paraffinembedded (FFPE) DNA and RNA have generally been extracted separately from either different tissue sections or from the same section by dividing the digested tissue. The former limits accurate correlation whilst the latter is impractical when utilizing rare or limited archived specimens. Principal Findings: For effective recovery of genomic DNA and total RNA from a single FFPE specimen, without splitting the proteinase-K digested tissue solution, we optimized a co-extraction method by using TRIzol and purifying DNA from the lower aqueous and RNA from the upper organic phases. Using a series of seven different archived specimens, we evaluated the total amounts of genomic DNA and total RNA recovered by our TRIzol-based co-extraction method and compared our results with those from two commercial kits, the Qiagen AllPrep DNA/RNA FFPE kit, for co-extraction, and the Ambion RecoverAll TM Total Nucleic Acid Isolation kit, for separate extraction of FFPE-DNA and-RNA. Then, to accurately assess the quality of DNA and RNA co-extracted from a single FFPE specimen, we used qRT-PCR, gene expression profiling and methylation assays to analyze microRNAs, mRNAs, and genomic DNA recovered from matched fresh and FFPE MCF10A cells. These experiments show that the TRIzol-based co-extraction method provides larger amounts of FFPE-DNA and –RNA tha
- …