368 research outputs found
Human oesophageal adenocarcinoma cell lines JROECL 47 and JROECL 50 are admixtures of the human colon carcinoma cell line HCT 116
In two recently described human oesophageal adenocarcinoma cell lines JROECL 47 and JROECL 50, derived from one tumour, we detected identical E-cadherin and ÎČ-catenin gene mutations as in colon carcinoma cell line HCT 116. We demonstrate by HLA-typing, mutation analysis and microsatellite analysis that cell lines JROECL 47 and JROECL 50 are admixtures of the human colon adenocarcinoma cell line HCT 116. © 2000 Cancer Research Campaig
High-Mass X-ray Binaries and the Spiral Structure of the Host Galaxy
We investigate the manifestation of the spiral structure in the distribution
of high-mass X-ray binaries (HMXBs) over the host galaxy. We construct the
simple kinematic model. It shows that the HMXBs should be displaced relative to
the spiral structure observed in such traditional star formation rate
indicators as the Halpha and FIR emissions because of their finite lifetimes.
Using Chandra observations of M51, we have studied the distribution of X-ray
sources relative to the spiral arms of this galaxy observed in Halpha. Based on
K-band data and background source number counts, we have separated the
contributions from high-mass and low-mass X-ray binaries and active galactic
nuclei. In agreement with model predictions, the distribution of HMXBs is wider
than that of bright HII regions concentrated in the region of ongoing star
formation. However, the statistical significance of this result is low, as is
the significance of the concentration of the total population of X-ray sources
to the spiral arms. We also predict the distribution of HMXBs in our Galaxy in
Galactic longitude. The distribution depends on the mean HMXB age and can
differ significantly from the distributions of such young objects as
ultracompact HII regions.Comment: 18 pages, 6 figures; Astronomy Letters, Vol. 33, No. 5, 2007, pp.
299-30
The effect of calcineurin inhibitor usage on hepatic fibrosis progression in HCV-positive liver transplant recipients:A two-centre study
Star Formation Thresholds in Galactic Disks
We report the first results of a detailed study of the star formation law in
a sample of 32 nearby spiral galaxies with well-measured rotation curves, HI
and H (as traced by CO) surface density profiles, and new \Ha CCD
photometry. Our results strongly support the view that the formation of
gravitationally bound interstellar clouds regulates the onset of widespread
star formation -- at least in the outer regions of galactic disks.Comment: Will appear in July 1 ApJ. Abbreviated abstract. Postscript version
available at http://www.astro.caltech.edu/~clm
The LBT Panoramic View on the Recent Star-Formation Activity in IC2574
We present deep imaging of the star-forming dwarf galaxy IC2574 in the M81
group taken with the Large Binocular Telescope in order to study in detail the
recent star-formation history of this galaxy and to constrain the stellar
feedback on its HI gas. We identify the star-forming areas in the galaxy by
removing a smooth disk component from the optical images. We construct
pixel-by-pixel maps of stellar age and stellar mass surface density in these
regions by comparing their observed colors with simple stellar populations
synthesized with STARBURST99. We find that an older burst occurred about 100
Myr ago within the inner 4 kpc and that a younger burst happened in the last 10
Myr mostly at galactocentric radii between 4 and 8 kpc. We analyze the stellar
populations residing in the known HI holes of IC2574. Our results indicate
that, even at the remarkable photometric depth of the LBT data, there is no
clear one-to-one association between the observed HI holes and the most recent
bursts of star formation in IC2574. The stellar populations formed during the
younger burst are usually located at the periphery of the HI holes and are seen
to be younger than the holes dynamical age. The kinetic energy of the holes
expansion is found to be on average 10% of the total stellar energy released by
the stellar winds and supernova explosions of the young stellar populations
within the holes. With the help of control apertures distributed across the
galaxy we estimate that the kinetic energy stored in the HI gas in the form of
its local velocity dispersion is about 35% of the total stellar energy.Comment: 16 pages, 14 figures, accepted for publication in Ap
CO(4-3) and dust emission in two powerful high-z radio galaxies, and CO lines at high redshifts
We report the detection of sub-mm emission from dust at 850 microns and of
the 12CO J=4-3 line in the two distant powerful radio galaxies 4C 60.07
(z=3.79) and 6C 1909+722 (z=3.53). In the case of 4C 60.07 the dust emission is
also detected at 1.25 mm. The estimated molecular gas masses are large, of the
order of ~(0.5-1)x10^{11} Solar. The large FIR luminosities (L_fir ~ 10^{13}
Solar) suggest that we are witnessing two major starburst phenomena, while the
observed large velocity widths (FWHM > 500 km/sec) are characteristic of
mergers. In the case of 4C 60.07 the CO emission extends over ~30 kpc and spans
a velocity range of >1000 km/sec. It consists of two distinct features with
FWHM of >= 550 km/sec and ~150 km/sec and line centers separated by >=700
km/sec The least massive of these components is probably very gas-rich with
potentially >=60% of its dynamical mass in the form of molecular gas. The
extraordinary morphology of the CO emission in this object suggests that it is
not just a scaled-up version of a local Ultra Luminous Infrared Galaxy, and it
may be a formative stage of the elliptical host of the residing radio-loud AGN.
Finally we briefly explore the effects of the wide range of gas excitation
conditions expected for starburst environments on the luminosity of high-J CO
lines. We conclude that in unlensed objects, CO (J+1-->J), J+1>3 lines can be
significantly weak with respect to CO J=1-0 and this can hinder their detection
even in the presence of substantial molecular gas masses.Comment: 34 pages, 5 figures, accepted for publication in The Astrophysical
Journa
Prognostic factors for survival in patients with advanced oesophageal cancer treated with cisplatin-based combination chemotherapy
The objective of this study was to identify prognostic factors for survival in patients with advanced oesophageal cancer, who are treated with cisplatin-based combination chemotherapy. We analysed the baseline characteristics of 350 patients who were treated in six consecutive prospective trials with one of the following regimens: cisplatin/etoposide, cisplatin/etoposide/5-fluorouracil, cisplatin/paclitaxel (weekly) and cisplatin/paclitaxel (biweekly). Predictive factors in univariate analyses were further evaluated using multivariate analysis (Cox regression). The median survival of all patients was 9 months. The 1, 2 and 5-year survival rates were 33, 12 and 4%, respectively. The main prognostic factors were found to be WHO performance status (0 or 1 vs 2), lactate dehydrogenase (normal vs elevated), extent of disease (limited disease defined as locoregional irresectable disease or lymph node metastases confined to either the supraclavicular or celiac region vs extensively disseminated disease) in addition to the type of treatment (weekly or biweekly cisplatin/paclitaxel regimen vs 4-weekly cisplatin/etoposide with or without 5-fluorouracil). Although weight loss, liver metastases and alkaline phosphatase were significant prognostic factors in univariate analyses, these factors lost their significance in multivariate analyses. The median survival for patients without any risk factors was 12 months, compared to only 4 months in patients with WHO 2 plus elevated LDH and extensive disease. The performance status, extent of disease, LDH and the addition of paclitaxel to cisplatin are independent prognostic factors in patients with advanced oesophageal cancer, who are treated with cisplatin-based combination chemotherapy
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