2,967 research outputs found
Development of siRNA-loaded lipid nanoparticles targeting long non-coding RNA LINC01257 as a novel and safe therapeutic approach for t(8;21) pediatric acute myeloid leukemia
Standard of care therapies for children with acute myeloid leukemia (AML) cause potent off-target toxicity to healthy cells, highlighting the need to develop new therapeutic approaches that are safe and specific for leukemia cells. Long non-coding RNAs (lncRNAs) are an emerging and highly attractive therapeutic target in the treatment of cancer due to their oncogenic functions and selective expression in cancer cells. However, lncRNAs have historically been considered ‘undruggable’ targets because they do not encode for a protein product. Here, we describe the development of a new siRNA-loaded lipid nanoparticle for the therapeutic silencing of the novel oncogenic lncRNA LINC01257. Transcriptomic analysis of children with AML identified LINC01257 as specifically expressed in t(8;21) AML and absent in healthy patients. Using NxGen microfluidic technology, we efficiently and reproducibly packaged anti-LINC01257 siRNA (LNP-si-LINC01257) into lipid nanoparticles based on the FDA-approved Patisiran (Onpattro®) formulation. LNP-si-LINC01257 size and ζ-potential were determined by dynamic light scattering using a Malvern Zetasizer Ultra. LNP-si-LINC01257 internalization and siRNA delivery were verified by fluorescence microscopy and flow cytometry analysis. lncRNA knockdown was determined by RT-qPCR and cell viability was characterized by flow cytometry-based apoptosis assay. LNP-siRNA production yielded a mean LNP size of ~65 nm with PDI ≤ 0.22 along with a >85% siRNA encapsulation rate. LNP-siRNAs were efficiently taken up by Kasumi-1 cells (>95% of cells) and LNP-si-LINC01257 treatment was able to successfully ablate LINC01257 expression which was accompanied by a significant 55% reduction in total cell count following 48 h of treatment. In contrast, healthy peripheral blood mononuclear cells (PBMCs), which do not express LINC01257, were unaffected by LNP-si-LINC01257 treatment despite comparable levels of LNP-siRNA uptake. This is the first report demonstrating the use of LNP-assisted RNA interference modalities for the silencing of cancer-driving lncRNAs as a therapeutically viable and non-toxic approach in the management of AML
Whole slide image registration for the study of tumor heterogeneity
Consecutive thin sections of tissue samples make it possible to study local
variation in e.g. protein expression and tumor heterogeneity by staining for a
new protein in each section. In order to compare and correlate patterns of
different proteins, the images have to be registered with high accuracy. The
problem we want to solve is registration of gigapixel whole slide images (WSI).
This presents 3 challenges: (i) Images are very large; (ii) Thin sections
result in artifacts that make global affine registration prone to very large
local errors; (iii) Local affine registration is required to preserve correct
tissue morphology (local size, shape and texture). In our approach we compare
WSI registration based on automatic and manual feature selection on either the
full image or natural sub-regions (as opposed to square tiles). Working with
natural sub-regions, in an interactive tool makes it possible to exclude
regions containing scientifically irrelevant information. We also present a new
way to visualize local registration quality by a Registration Confidence Map
(RCM). With this method, intra-tumor heterogeneity and charateristics of the
tumor microenvironment can be observed and quantified.Comment: MICCAI2018 - Computational Pathology and Ophthalmic Medical Image
Analysis - COMPA
Medication education program for Indian children with asthma: A feasibility study
Objective: It is postulated that children with asthma who receive an interactive, comprehensive, culturally relevant education program would improve their asthma knowledge (AK), asthma control, and adherence compared with children receiving usual care. The aim of this study was to develop, implement, and evaluate the efficacy of a culturally relevant asthma education intervention for children with asthma and their parents in India.Methods: Children with asthma (7.12 years) and their parents were recruited from an outpatient clinic in a Chest Diseases Hospital in New Delhi, and were randomly assigned to either an intervention or usual care group. At baseline, outcome data collected included pediatric asthma caregiver quality of life (PACQL, primary outcome), AK, asthma control, adherence, inhaler technique, action plan ownership, and goal achievement. These data were collected again at 1 and 6 months after baseline. Outcomes were compared within and between groups using ANOVA techniques.Results: Forty parent.child pairs were recruited. Of these, 24 pairs of children with asthma and their parents received the educational intervention. The PACQL significantly improved from baseline to 6 months in the intervention (5.87 } 0.94.7.00 } 0.03) versus the usual care group (5.90 } 0.52.6.34 } 0.56) (P < 0.001). Other outcomes such as the parentsf and childfs AK, childfs asthma control and inhaler technique were significantly improved in the intervention group across the study. All the participants possessed a written asthma action plan at the end of the intervention. Eighty.five goals were set by children with asthma across all the visits and were achieved by completion.Conclusion: An asthma educator delivered interactive program simultaneously involving children with asthma and their parents, improved quality of life, empowered and promoted better self.management skills.Key words: Asthma education, asthma knowledge, asthma usual care, caregiver quality of life, childhood asthma, hospital.based program, program evaluatio
The evolution of Balmer jump selected galaxies in the ALHAMBRA survey
We present a new color-selection technique, based on the Bruzual & Charlot
models convolved with the bands of the ALHAMBRA survey, and the redshifted
position of the Balmer jump to select star-forming galaxies in the redshift
range 0.5 < z < 1.5. These galaxies are dubbed Balmer jump Galaxies BJGs. We
apply the iSEDfit Bayesian approach to fit each detailed SED and determine
star-formation rate (SFR), stellar mass, age and absolute magnitudes. The mass
of the haloes where these samples reside are found via a clustering analysis.
Five volume-limited BJG sub-samples with different mean redshifts are found to
reside in haloes of median masses slightly
increasing toward z=0.5. This increment is similar to numerical simulations
results which suggests that we are tracing the evolution of an evolving
population of haloes as they grow to reach a mass of at z=0.5. The likely progenitors of our samples at z3 are Lyman
Break Galaxies, which at z2 would evolve into star-forming BzK galaxies,
and their descendants in the local Universe are elliptical galaxies.Hence, this
allows us to follow the putative evolution of the SFR, stellar mass and age of
these galaxies. From z1.0 to z0.5, the stellar mass of the volume
limited BJG samples nearly does not change with redshift, suggesting that major
mergers play a minor role on the evolution of these galaxies. The SFR evolution
accounts for the small variations of stellar mass, suggesting that star
formation and possible minor mergers are the main channels of mass assembly.Comment: 14 pages, 10 figures. Submitted to A&A. It includes first referee's
comments. Abstract abridged due to arXiv requirement
N-body simulation of the Stephan's Quintet
The evolution of compact groups of galaxies may represent one of the few
places in the nearby universe in which massive galaxies are being forged
through a complex set of processes involving tidal interaction, ram-pressure
stripping, and perhaps finally "dry-mergers" of galaxies stripped of their cool
gas. Using collisionless N-body simulations, we propose a possible scenario for
the formation of one of the best studied compact groups: Stephan's Quintet. We
define a serial approach which allows us to consider the history of the group
as sequence of galaxy-galaxy interactions seen as relatively separate events in
time, but chained together in such a way as to provide a plausible scenario
that ends in the current configuration of the galaxies. By covering a large set
of parameters, we claim that it is very unlikely that both major tidal tails of
the group have been created by the interaction between the main galaxy and a
single intruder. We propose instead a scenario based on two satellites orbiting
the main disk, plus the recent involvement of an additional interloper, coming
from the background at high speed. This purely N-body study of the quintet will
provide a parameter-space exploration of the basic dynamics of the group that
can be used as a basis for a more sophisticated N-body/hydrodynamic study of
the group that is necessary to explain the giant shock structure and other
purely gaseous phenomena observed in both the cold, warm and hot gas in the
group.Comment: 13 pages, 13 figures. Accepted for publication in Ap
Integral Field Spectroscopy of the Central Regions of 3C 120: Evidence of a Past Merging Event
IFS combined with HST WFPC imaging were used to characterize the central
regions of the Seyfert 1 radio galaxy 3C 120. We carried out the analysis of
the data, deriving intensity maps of different emission lines and the continua
at different wavelengths from the observed spectra. Applying a 2D modeling to
the HST images we decoupled the nucleus and the host galaxy, and analyzed the
host morphology. The host is a highly distorted bulge dominated galaxy, rich in
substructures. We developed a new technique to model the IFS data extending the
2D modeling. Using this technique we separated the Seyfert nucleus and the host
galaxy spectra, and derived a residual data cube with spectral and spatial
information of the different structures in 3C 120. Three continuum-dominated
structures (named A, B, and C) and other three extended emission line regions
(EELRs, named E1, E2 and E3) are found in 3C 120 which does not follow the
general behavior of a bulge dominated galaxy. We also found shells in the
central kpc that may be remnants of a past merging event in this galaxy. The
origin of E1 is most probably due to the interaction of the radio-jet of 3C 120
with the intergalactic medium. Structures A, B, and the shell at the southeast
of the nucleus seem to correspond to a larger morphological clumpy structure
that may be a tidal tail, consequence of the past merging event. We found a
bright EELR (E2) in the innermost part of this tidal tail, nearby the nucleus,
which shows a high ionization level. The kinematics of the E2 region and its
connection to the tidal tail suggest that the tail has channeled gas from the
outer regions to the center.Comment: 55 pages, 18 figures and 5 tables Accepted by AP
The ALHAMBRA photometric system
This paper presents the characterization of the optical range of the ALHAMBRA
photometric system, a 20 contiguous, equal-width, medium-band CCD system with
wavelength coverage from 3500A to 9700A. The photometric description of the
system is done by presenting the full response curve as a product of the
filters, CCD and atmospheric transmission curves, and using some first and
second order moments of this response function. We also introduce the set of
standard stars that defines the system, formed by 31 classic spectrophotometric
standard stars which have been used in the calibration of other known
photometric systems, and 288 stars, flux calibrated homogeneously, from the
Next Generation Spectral Library (NGSL). Based on the NGSL, we determine the
transformation equations between Sloan Digital Sky Survey (SDSS) ugriz
photometry and the ALHAMBRA photometric system, in order to establish some
relations between both systems. Finally we develop and discuss a strategy to
calculate the photometric zero points of the different pointings in the
ALHAMBRA project.Comment: Astronomical Journal on the 14th of January 201
JPCam: A 1.2Gpixel camera for the J-PAS survey
JPCam is a 14-CCD mosaic camera, using the new e2v 9k-by-9k 10microm-pixel
16-channel detectors, to be deployed on a dedicated 2.55m wide-field telescope
at the OAJ (Observatorio Astrofisico de Javalambre) in Aragon, Spain. The
camera is designed to perform a Baryon Acoustic Oscillations (BAO) survey of
the northern sky. The J-PAS survey strategy will use 54 relatively narrow-band
(~13.8nm) filters equi-spaced between 370 and 920nm plus 3 broad-band filters
to achieve unprecedented photometric red-shift accuracies for faint galaxies
over ~8000 square degrees of sky. The cryostat, detector mosaic and read
electronics is being supplied by e2v under contract to J-PAS while the
mechanical structure, housing the shutter and filter assembly, is being
designed and constructed by a Brazilian consortium led by INPE (Instituto
Nacional de Pesquisas Espaciais). Four sets of 14 filters are placed in the
ambient environment, just above the dewar window but directly in line with the
detectors, leading to a mosaic having ~10mm gaps between each CCD. The massive
500mm aperture shutter is expected to be supplied by the Argelander-Institut
fur Astronomie, Bonn. We will present an overview of JPCam, from the filter
configuration through to the CCD mosaic camera. A brief outline of the main
J-PAS science projects will be included.Comment: 11 pages and 9 figure
- …