52 research outputs found
Acute hepatitis in three patients with systemic juvenile idiopathic arthritis taking interleukin-1 receptor antagonist
<p>Abstract</p> <p>Purpose</p> <p>We investigated the etiology of acute hepatitis in three children with systemic Juvenile Idiopathic Arthritis (sJIA) taking Interleukin-1 receptor antagonist (IL1RA).</p> <p>Methods</p> <p>Laboratory and clinical data for three children with sJIA diagnosed at ages 13 months to 8 years who developed acute hepatitis during treatment with IL1RA were reviewed for evidence of sJIA flare, infection, macrophage activation syndrome (MAS), malignancy, and drug reaction.</p> <p>Results</p> <p>In all patients, hepatitis persisted despite cessation of known hepatotoxic drugs and in absence of known infectious triggers, until discontinuation of IL1RA. Liver biopsies had mixed inflammatory infiltrates with associated hepatocellular injury suggestive of an exogenous trigger. At the time of hepatitis, laboratory data and liver biopsies were not characteristic of MAS. In two patients, transaminitis resolved within one week of discontinuing IL1RA, the third improved dramatically in one month.</p> <p>Conclusions</p> <p>Although sJIA symptoms improved significantly on IL1RA, it appeared that IL1RA contributed to the development of acute hepatitis. Hepatitis possibly occurred as a result of an altered immune response to a typical childhood infection while on IL1RA. Alternatively, hepatitis could have represented an atypical presentation of MAS in patients with sJIA taking IL1RA. Further investigation is warranted to determine how anti-IL1 therapies alter immune responsiveness to exogenous triggers in patients with immune dysfunction such as sJIA. Our patients suggest that close monitoring for hepatic and other toxicities is indicated when treating with IL1RA.</p
Characterization of an Ionization Readout Tile for nEXO
A new design for the anode of a time projection chamber, consisting of a
charge-detecting "tile", is investigated for use in large scale liquid xenon
detectors. The tile is produced by depositing 60 orthogonal metal
charge-collecting strips, 3~mm wide, on a 10~\si{\cm} 10~\si{\cm}
fused-silica wafer. These charge tiles may be employed by large detectors, such
as the proposed tonne-scale nEXO experiment to search for neutrinoless
double-beta decay. Modular by design, an array of tiles can cover a sizable
area. The width of each strip is small compared to the size of the tile, so a
Frisch grid is not required. A grid-less, tiled anode design is beneficial for
an experiment such as nEXO, where a wire tensioning support structure and
Frisch grid might contribute radioactive backgrounds and would have to be
designed to accommodate cycling to cryogenic temperatures. The segmented anode
also reduces some degeneracies in signal reconstruction that arise in
large-area crossed-wire time projection chambers. A prototype tile was tested
in a cell containing liquid xenon. Very good agreement is achieved between the
measured ionization spectrum of a Bi source and simulations that
include the microphysics of recombination in xenon and a detailed modeling of
the electrostatic field of the detector. An energy resolution =5.5\%
is observed at 570~\si{keV}, comparable to the best intrinsic ionization-only
resolution reported in literature for liquid xenon at 936~V/\si{cm}.Comment: 18 pages, 13 figures, as publishe
Sensitivity and discovery potential of the proposed nEXO experiment to neutrinoless double beta decay
The next-generation Enriched Xenon Observatory (nEXO) is a proposed
experiment to search for neutrinoless double beta () decay in
Xe with a target half-life sensitivity of approximately years
using kg of isotopically enriched liquid-xenon in a time
projection chamber. This improvement of two orders of magnitude in sensitivity
over current limits is obtained by a significant increase of the Xe
mass, the monolithic and homogeneous configuration of the active medium, and
the multi-parameter measurements of the interactions enabled by the time
projection chamber. The detector concept and anticipated performance are
presented based upon demonstrated realizable background rates.Comment: v2 as publishe
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