360 research outputs found
Reliability of 2D ultrasound imaging associated with transient ShearWave Elastography method to analyze spastic gastrocnemius medialis muscle architecture and viscoelastic properties
PurposeThe aim of the study was to assess the reliability of pennation angle (PA) and muscle thickness (MT) 2D measurements and of shear elastic modulus measurement, using ultrasound imaging (US). Those measurements were made on spastic gastrocnemius medialis muscle at rest and at maximal passive stretching, in post-stroke hemiplegic patients. The paretic side measurements were compared to non-paretic side.Material and methodsFourteen patients took part in 2 inter-session reliability experiments, realized at a 7 days interval by the same operator. The Aixplorer® Supersonic US scanner with the transient ShearWave Elastography (SWE) software was used. The stretching experiments were made manually and controlled by a goniometer.ResultsThe reliability of the 2D measurements was good. The coefficient of variation (CV) was 6.30% for MT measurement at rest, 6.40% and 8.26% for PA at rest and at maximal passive stretching respectively. The reliability of the shear elastic modulus measurement in the sagittal plane was good only at rest with a CV of 9.86%, versus 40.58% at stretching. None of the shear elastic modulus measurements in the axial plane were good. At rest, MT and PA were weaker on the paretic side (14.25±3.12mm and 17.32±5.10°) versus non-paretic side (16.30±3.19mm and 21.08±5.05°) (P<0.0001 and P=0.006). At rest, there was a small difference in the shear elastic modulus between the paretic side and the non-paretic side (5.40±1.67kPa versus 6.20±2.18kPa, P=0.041).DiscussionThis is the first description of muscle spastic structure using SWE with Supersonic Shear Imaging. 2D US associated with SWE shows promise in terms of muscular atrophy quantification and muscle histological quality assessment. These structural properties reflect some of the functional abilities regardless of motor control. It should enable further research on therapies, which impact muscle tissue quality, such as botulinum neurotoxin injections
NOD × 129.H2g7 Backcross Delineates 129S1/SvImJ-Derived Genomic Regions Modulating Type 1 Diabetes Development in Mice
OBJECTIVE: Introduction of genes targeted in 129/Sv embryonic stem (ES) cells into NOD mice brings about linked genes that may modulate type 1 diabetes. Our objective was to identify 129S1/SvJ non-MHC regions contributing type 1 diabetes resistance or susceptibility in backcross to NOD/LtJ. RESEARCH DESIGN AND METHODS: After congenic transfer of the NOD H2(g7) haplotype onto 129S1/Sv, 310 females were produced by NOD x (NOD x 129.H2(g7))F1 backcross (N2). A genome scan for quantitative trait locus (QTL) affecting clinical diabetes, age of diabetes onset, and insulitis severity was performed using subphenotype characteristics to improve power and resolution for detection of diabetes susceptibility loci. RESULTS: Thirty-six of 310 (11.6%) N2 females developed type 1 diabetes between 14 and 40 weeks. Significant evidence of linkage for only a single previously reported Idd complex locus (Idd10/17/18, chromosome [Chr] 3) was indicated for clinical diabetes. The quantitative traits of insulitis either alone or combined with age at type 1 diabetes onset were significantly linked to known Idd regions on Chr 1 (Idd5 region), Chr 4 (Idd9 region), Chr 8 (Idd22), Chr 11 (Idd4.3), and proximal Chr 17 (Idd16 region). Significant 129S1/Sv resistance contributions were identified on Chr 1, 15 (two loci), and 19, with suggestive evidence for additional novel 129/Sv resistance QTL on Chr 5 and 17 and susceptibility on Chr 2. CONCLUSIONS: The 129S1/SvJ genome harbors collections of both known and potentially novel non-MHC Idd loci. Investigators targeting 129/Sv genes mapping within chromosomal regions reported herein or elsewhere in the genome need to exclude potential contributions from linked Idd loci by generating a NOD.129 control strain expressing the nontargeted allele
A Study of the Luminosity and Mass Functions of the Young IC 348 Cluster using FLAMINGOS Wide-Field Near-Infrared Images
We present wide-field near-infrared (JHK) images of the young, 2 Myr IC 348
cluster taken with FLAMINGOS. We use these new data to construct an infrared
census of sources, which is sensitive enough to detect a 10 Mjup brown dwarf
seen through an extinction of Av=7mag. We examine the cluster's structure and
relationship to the molecular cloud and construct the cluster's K band
luminosity function. Using our model luminosity function algorithm, we derive
the cluster's initial mass function throughout the stellar and substellar
regimes and find that the IC 348 IMF is very similar to that found for the
Trapezium Cluster with both cluster IMFs having a mode between 0.2 - 0.08 Msun.
In particular we find that, similar to our results for the Trapezium, brown
dwarfs constitute only 1 in 4 of the sources in the IC 348 cluster. We show
that a modest secondary peak forms in the substellar IC 348 KLF, corresponding
to the same mass range responsible for a similar KLF peak found in the
Trapezium. We interpret this KLF peak as either evidence for a corresponding
secondary IMF peak at the deuterium burning limit, or as arising from a feature
in the substellar mass-luminosity relation that is not predicted by current
theoretical models. Lastly, we find that IC 348 displays radial variations of
its sub-solar (0.5 - 0.08 Msun) IMF on a parsec scale. Whatever mechanism that
is breaking the universality of the IMF on small spatial scales in IC 348 does
not appear to be acting upon the brown dwarf population, whose relative size
does not vary with distance from the cluster center.Comment: 53 pages, 20 figures, AASTeX5.0. Color version of Figure 1 made
available in jpg format. Figure(s) 2,3,5 are reduced in resolution. Accepted
14 Jan 2003 to the Astronomical Journa
International multicentre observational study to assess the efficacy and safety of a 0·5 mg kg−1 per day starting dose of oral corticosteroids to treat bullous pemphigoid
BackgroundEuropean guidelines propose a 0 center dot 5 mg kg(-1) per day dose of oral prednisone as initial treatment for bullous pemphigoid (BP). We assessed the safety and efficacy of this regimen depending on BP extent and general condition of the patients.MethodsIn a prospective international study, we consecutively included all patients diagnosed with BP. Patients received a 0 center dot 5 mg kg(-1) per day dose of prednisone, which was then gradually tapered 15 days after disease control, with the aim of stopping prednisone or maintaining minimal treatment (0 center dot 1 mg kg(-1) per day) within 6 months after the start of treatment. The two coprimary endpoints were control of disease activity at day 21 and 1-year overall survival. Disease severity was assessed according to the Bullous Pemphigoid Disease Area Index (BPDAI) score.ResultsIn total, 198 patients were included between 2015 and 2017. The final analysis comprised 190 patients with a mean age of 80 center dot 9 (SD 9 center dot 1) years. Control of disease activity was achieved at day 21 in 119 patients [62 center dot 6%, 95% confidence interval (CI) 55 center dot 3-69.5]; 18 of 24 patients (75%, 95% CI 53 center dot 3-90 center dot 2), 75 of 110 patients (68 center dot 8%, 95% CI 59 center dot 2-77 center dot 3) and 26 of 56 patients (46.4%, 95% CI 33 center dot 0-60 center dot 3) had mild, moderate and severe BP, respectively (P = 0 center dot 0218). A total of 30 patients died during the study. The overall Kaplan-Meier 1-year survival was 82 center dot 6% (95% CI 76 center dot 3-87 center dot 4) corresponding to 90 center dot 9%, 83 center dot 0% and 80 center dot 0% rates in patients with mild, moderate and severe BP, respectively (P = 0 center dot 5). Thresholds of 49 points for BPDAI score and 70 points for Karnofsky score yielded maximal Youden index values with respect to disease control at day 21 and 1-year survival, respectively.ConclusionsA 0 center dot 5 mg kg(-1) per day dose of prednisone is a valuable therapeutic option in patients with mild or moderate BP whose general condition allows them to be autonomous.</p
Projection of circumstellar disks on their environments
We use a 3D Monte Carlo radiative transfer code to study the projection of
large shadows by circumstellar disks around young stellar objects on
surrounding reflection nebulosity. It is shown that for a wide range of
parameters a small (10-100 AU) circumstellar disk can project a large (1 000-10
000 AU) dark band in the near-infrared that often resembles a massive edge-on
disk. The disk shadows are divided into two basic types, depending on the
distribution of the reflecting material and the resulting morphology of the
shadows in the near-infrared. Two YSOs associated with bipolar nebulosity, CK
3/EC 82 illuminating the Serpens Reflection Nebula (SRN) and Ced 110 IRS 4 in
the Chamaeleon I molecular cloud, are modelled in detail as disk shadows.
Spectral energy distributions of the two sources are collected using both
archival ISO data and new Spitzer-IRS data. An axisymmetric model consisting of
a small disk and a spherically symmetric envelope can reproduce the
near-infrared images and full spectral energy distributions of the two disk
shadow candidates. It is shown that the model fits can be used to constrain the
geometry of the central disks due to the magnifying effect of the projection.
We find that a disk unresolved in near-infrared images, but casting a large
disk shadow, can be modelled at a level of sophistication approaching that of
an edge-on disk with resolved near-infrared images. It is found that the most
obvious observable difference between a disk shadow and a large optically thick
disk is that the disk shadows have a compact near-infrared source near the
center of the dark band. High resolution imaging and/or polarimetry should
reveal the compact source in the center of a disk shadow as an edge-on disk.
[Abstract abridged]Comment: 16 pages, 12 figures, accepted for publication in Astronomy &
Astrophysic
Asbestos-related pleural and lung fibrosis in patients with retroperitoneal fibrosis
<p>Abstract</p> <p>Background</p> <p>Retroperitoneal fibrosis (RPF) is a rare fibroinflammatory disease that leads to hydronephrosis and renal failure. In a case-control study, we have recently shown that asbestos exposure was the most important risk factor for RPF in the Finnish population. The aim of this study was to evaluate the relation of asbestos exposure to radiologically confirmed lung and pleural fibrosis among patients with RPF.</p> <p>Methods</p> <p>Chest high-resolution computed tomography (HRCT) was performed on 16 unexposed and 22 asbestos-exposed RPF patients and 18 asbestos-exposed controls. Parietal pleural plaques (PPP), diffuse pleural thickening (DPT) and parenchymal fibrosis were scored separately.</p> <p>Results</p> <p>Most of the asbestos-exposed RPF patients and half of the asbestos-exposed controls had bilateral PPP, but only a few had lung fibrosis. Minor bilateral plaques were detected in two of the unexposed RPF patients, and none had lung fibrosis. DPT was most frequent and thickest in the asbestos-exposed RPF-patients. In three asbestos-exposed patients with RPF we observed exceptionally large pleural masses that were located anteriorly in the pleural space and continued into the anterior mediastinum.</p> <p>Asbestos exposure was associated with DPT in comparisons between RPF patients and controls (case-control analysis) as well as among RPF patients (case-case analysis).</p> <p>Conclusion</p> <p>The most distinctive feature of the asbestos-exposed RPF patients was a thick DPT. An asbestos-related pleural finding was common in the asbestos-exposed RPF patients, but only a few of these patients had parenchymal lung fibrosis. RPF without asbestos exposure was not associated with pleural or lung fibrosis. The findings suggest a shared etiology for RPF and pleural fibrosis and furthermore possibly a similar pathogenetic mechanisms.</p
X Chromosome Inactivation and Differentiation Occur Readily in ES Cells Doubly-Deficient for MacroH2A1 and MacroH2A2
Macrohistones (mH2As) are unusual histone variants found exclusively in vertebrate chromatin. In mice, the H2afy gene encodes two splice variants, mH2A1.1 and mH2A1.2 and a second gene, H2afy2, encodes an additional mH2A2 protein. Both mH2A isoforms have been found enriched on the inactive X chromosome (Xi) in differentiated mammalian female cells, and are incorporated into the chromatin of developmentally-regulated genes. To investigate the functional significance of mH2A isoforms for X chromosome inactivation (XCI), we produced male and female embryonic stem cell (ESC) lines with stably-integrated shRNA constructs that simultaneously target both mH2A1 and mH2A2. Surprisingly, we find that female ESCs deficient for both mH2A1 and mH2A2 readily execute and maintain XCI upon differentiation. Furthermore, male and female mH2A-deficient ESCs proliferate normally under pluripotency culture conditions, and respond to several standard differentiation procedures efficiently. Our results show that XCI can readily proceed with substantially reduced total mH2A content
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