808 research outputs found
Deep CCD Surface Photometry of the Edge-On Spiral NGC 4244
We have obtained deep surface photometry of the edge-on spiral galaxy NGC
4244. Our data reliably reach 27.5 R magnitude arcsec^{-2}, a significant
improvement on our earlier deep CCD surface photometry of other galaxies. NGC
4244 is a nearby Scd galaxy whose total luminosity is approximately one
magnitude fainter than the peak of the Sc luminosity function. We find that it
has a simple structure: a single exponential disk, with a scale height h_Z =
246 +/- 2 pc, a scale length h_R = 1.84 +/- 0.02 kpc and a disk cutoff at a
radius R(max) = 10.0 kpc (5.4 scale lengths). We confirm a strong cutoff in the
stellar disk at R(max), which happens over only 1 kpc. We do not see any
statistically significant evidence for disk flaring with radius. Unlike the
more luminous Sc galaxies NGC 5907 and M 33, NGC 4244 does not show any
evidence for a second component, such as a thick disk or halo, at mu(R) < 27.5
magnitude arcsec^{-2}.Comment: 36 pages, including 12 figures; accepted for publication in Sept 99
A
Regulation of IFN response gene activity during infliximab treatment in rheumatoid arthritis is associated with clinical response to treatment
ABSTRACT: INTRODUCTION: Cross-regulation between tumor necrosis factor (TNF) and type I interferon (IFN) has been postulated to play an important role in autoimmune diseases. Therefore we determined the effect of TNF-blockade in rheumatoid arthritis (RA) on the type I IFN-response gene activity in relation to clinical response. METHODS: Peripheral blood from 33 RA patients was collected in PAXgene tubes before and after the start of infliximab treatment. In a first group of 15 patients the baseline expression of type I IFN-regulated genes was determined using cDNA-microarrays and compared to levels one month after treatment. The remaining 18 patients were studied as an independent group for validation using quantitative (q)PCR. RESULTS: Gene expression analysis revealed that anti-TNF antibody treatment induced a significant increase in type I IFN-response activity in a subset of RA patients, whereas expression levels remained similar or were slightly decreased in others. The findings appear clinically relevant since patients with an increased IFN-response gene activity after anti-TNF therapy had a poor clinical outcome. This association was confirmed and extended for an IFN-response gene set consisting of OAS1, LGALS3BP, Mx2, OAS2 and SERPING1 in five EULAR good and five EULAR poor responders, by qPCR. CONCLUSIONS: Regulation of IFN-response gene activity upon TNF-blockade in RA is not as consistent as previously described, but varies between patients. The differential changes in IFN-response gene activity appear relevant to the clinical outcome of TNF-blockade in R
The Features of the Synovium in Early Rheumatoid Arthritis According to the 2010 ACR/EULAR Classification Criteria
OBJECTIVES: It has been shown in early arthritis cohorts that the 2010 ACR/EULAR criteria for rheumatoid arthritis (RA) enable an earlier diagnosis, perhaps at the cost of a somewhat more heterogeneous patient population. We describe the features of synovial inflammation in RA patients classified according to these new criteria. METHODS: At baseline, synovial tissue biopsy samples were obtained from disease-modifying antirheumatic drug (DMARD)-naĂŻve early RA patients (clinical signs and symptoms <1 year). Synovial tissue was analyzed for cell infiltration, vascularity, and expression of adhesion molecules. Stained sections were evaluated by digital image analysis. Patients were classified according to the two different sets of classification criteria, autoantibody status, and outcome. FINDINGS: Synovial tissue of 69 RA patients according to 2010 ACR/EULAR criteria was analyzed: 56 patients who fulfilled the criteria for RA at baseline and 13 who were initially diagnosed as undifferentiated arthritis but fulfilled criteria for RA upon follow up. The synovium at baseline was infiltrated by plasma cells, macrophages, and T cells as well as other cells, and findings were comparable to those when patients were selected based on the 1987 ACR criteria for RA. There was no clear cut difference in the characteristics of the synovium between RA patients initially diagnosed as undifferentiated arthritis and those who already fulfilled classification criteria at baseline. CONCLUSION: The features of synovial inflammation are similar when the 2010 ACR/EULAR classification criteria are used compared to the 1987 ACR criteria
Multiwavelength study of the nuclei of a volume-limited sample of galaxies I: X-ray observations
We discuss ROSAT HRI X-ray observations of 33 very nearby galaxies, sensitive
to X-ray sources down to a luminosity of approximately 10^38 erg/s. The
galaxies are selected from a complete, volume limited sample of 46 galaxies
with d<7 Mpc for which we have extensive multi-wavelength data. For an almost
complete sub-sample with M_B<-14 (29/31 objects) we have HRI images. Contour
maps and source lists are presented within the central region of each galaxy,
together with nuclear upper limits where no nuclear source was detected.
Nuclear X-ray sources are found to be very common, occurring in ~35% of the
sample. Nuclear X-ray luminosity is statistically connected to host galaxy
luminosity - there is not a tight correlation, but the probability of a nuclear
source being detected increases strongly with galaxy luminosity and the
distribution of nuclear luminosities seems to show an upper envelope that is
roughly proportional to galaxy luminosity. While these sources do seem to be a
genuinely nuclear phenomenon rather than nuclear examples of the general X-ray
source population, it is far from obvious that they are miniature Seyfert
nuclei. The more luminous nuclei are very often spatially extended, and HII
region nuclei are detected just as often as LINERs. Finally, we also note the
presence of fairly common super-luminous X-ray sources in the off-nuclear
population - out of 29 galaxies we find 9 sources with a luminosity larger than
10^39 erg/s. These show no particular preference for more luminous galaxies.
One is already known to be a multiple SNR system, but most have no obvious
optical counterpart and their nature remains a mystery.Comment: Accepted for publication in MNRAS. 26 pages, 47 figures (figures
1-29,31 and 38 as separate, low resolution files; full resolution files are
available at http://www.star.le.ac.uk/~plt
A Massive Spiral Galaxy in the Zone of Avoidance
We report the discovery of a very HI-massive disk galaxy, HIZOA J0836-43, at
a velocity of v_hel = 10689 km/s, corresponding to a distance of 148 Mpc
(assuming H_0=75 km/s/Mpc). It was found during the course of a systematic HI
survey of the southern Zone of Avoidance (|b| < 5 deg) with the multibeam
system at the 64m Parkes radio telescope. Follow-up observations with the
Australia Telescope Compact Array (ATCA) reveal an extended HI disk. We derive
an HI mass of 7.5 x 10^10 Msun. Using the HI radius, we estimate a total
dynamical mass of 1.4 x 10^12 Msun, similar to the most massive known disk
galaxies such as Malin 1. HIZOA J0836-43 lies deep in the Zone of Avoidance (l,
b = 262.48 deg, -1.64 deg) where the optical extinction is very high, A_B =
9.8. However, in the near-infrared wavebands, where the extinction is
considerably lower, HIZOA J0836-43 is clearly detected by both DENIS and 2MASS.
Deep AAT near-infrared (Ks and H-band) images show that HIZOA J0836-43 is an
inclined disk galaxy with a prominent bulge (scale length 2.5 arcsec or 1.7
kpc), and an extended disk (scale length 7 arcsec or 4.7 kpc) which can be
traced along the major axis out to a radius of 20 arcsec or 13.4 kpc (at 20
mag/arcsec^2 in Ks). The HI disk is much more extended, having a radius of 66
kpc at 1 Msun/pc^2. Detections in the radio continuum at 1.4 GHz and at 60
micron (IRAS) are consistent with HIZOA J0836-43 forming stars at a rate of ~35
Msun/yr. We compare the properties of HIZOA J0836-43 with those of the most
HI-massive galaxies currently known, UGC 4288, UGC 1752 and Malin 1, all of
which are classified as giant low surface brightness galaxies.Comment: Accepted for publication in MNRAS, 17 pages, 11 figures, 7 tables,
version with high-resolution figures available at:
http://frodo.as.arizona.edu/~jdonley/massive
Predicting procedure duration of colorectal endoscopic submucosal dissection at Western endoscopy centers
Background and study aims Overcoming logistical obstacles for the implementation of colorectal endoscopic submucosal dissection (ESD) requires accurate prediction of procedure times. We aimed to evaluate existing and new prediction models for ESD duration.Patients and methods Records of all consecutive patients who underwent single, non-hybrid colorectal ESDs before 2020 at three Dutch centers were reviewed. The performance of an Eastern prediction model [GIE 2021;94(1):133–144] was assessed in the Dutch cohort. A prediction model for procedure duration was built using multivariable linear regression. The model’s performance was validated using internal validation by bootstrap resampling, internal-external cross-validation and external validation in an independent Swedish ESD cohort.Results A total of 435 colorectal ESDs were analyzed (92% en bloc resections, mean duration 139 minutes, mean tumor size 39 mm). The performance of current unstandardized time scheduling practice was suboptimal (explained variance: R2=27%). We successfully validated the Eastern prediction model for colorectal ESD duration <60 minutes (c-statistic 0.70, 95% CI 0.62–0.77), but this model was limited due to dichotomization of the outcome and a relatively low frequency (14%) of ESDs completed <60 minutes in the Dutch centers. The model was more useful with a dichotomization cut-off of 120 minutes (c-statistic: 0.75; 88% and 17% of “easy” and “very difficult” ESDs completed <120 minutes, respectively). To predict ESD duration as continuous outcome, we developed and validated the six-variable cESD-TIME formula (https://cesdtimeformula.shinyapps.io/calculator/; optimism-corrected R2=61%; R2=66% after recalibration of the slope).Conclusions We provided two useful tools for predicting colorectal ESD duration at Western centers. Further improvements and validations are encouraged with potential local adaptation to optimize time planning
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