657 research outputs found
CHD5 is down-regulated through promoter hypermethylation in gastric cancer
<p>Abstract</p> <p>Background</p> <p>Nonhistone chromosomal proteins in concert with histones play important roles in the replication and repair of DNA and in the regulation of gene expression. The deregulation of these proteins can contribute to the development of a variety of diseases such as cancer. As a nonhistone chromosomal protein, chromodomain helicase DNA binding protein 5 (CHD5) has recently been identified as the product of a novel tumor suppressor gene (TSG), promoting the transcription of p19<sup><it>ink4a </it></sup>and p16<sup><it>arf</it></sup>. The inactivation of CHD5 was achieved partly through genetic deletion since it is located in 1p36, a region frequently deleted in human tumors. In this study, we aim to study the involvement of CHD5 in gastric cancer, the second most common cancer worldwide.</p> <p>Methods</p> <p>CHD5 expression in a panel of gastric cancer cells were determined by quantitative RT-PCR. The methylation of CHD5 was evaluated by methylation specific PCR and bisulfite genome sequencing. The effect of CHD5 on growth of gastric cancer cells was tested by colony formation assay.</p> <p>Results</p> <p>CHD5 expression was down-regulated in all of gastric cancer cell lines used (100%, 7/7) and significantly restored after pharmacological demethylation. Methylation of CHD5 promoter was detected in all of seven gastric cancer cell lines and in the majority of primary gastric carcinoma tissues examined (73%, 11/15). Finally, ectopic expression of CHD5 in gastric cancer cells led to a significant growth inhibition.</p> <p>Conclusion</p> <p>CHD5 was a TSG epigenetically down-regulated in gastric cancer.</p
Epitaxial Bi2FeCrO6 Multiferroic Thin Films
We present here experimental results obtained on Bi2FeCrO6 (BFCO) epitaxial
films deposited by laser ablation directly on SrTiO3 substrates. It has been
theoretically predicted, by Baettig and Spaldin, using first-principles density
functional theory that BFCO is ferrimagnetic (with a magnetic moment of 2 Bohr
magneton per formula unit) and ferroelectric (with a polarization of ~80
microC/cm2 at 0K). The crystal structure has been investigated using X-ray
diffraction which shows that the films are epitaxial with a high crystallinity
and have a degree of orientation depending of the deposition conditions and
that is determined by the substrate crystal structure. Chemical analysis
carried out by X-ray Microanalysis and X-ray Photoelectron Spectroscopy (XPS)
indicates the correct cationic stoichiometry in the BFCO layer, namely
(Bi:Fe:Cr = 2:1:1). XPS depth profiling revealed that the oxidation state of Fe
and Cr ions in the film remains 3+ throughout the film thickness and that both
Fe and Cr ions are homogeneously distributed throughout the depth.
Cross-section high-resolution transmission electron microscopy images together
with selected area electron diffraction confirm the crystalline quality of the
epitaxial BFCO films with no identifiable foreign phase or inclusion. The
multiferroic character of BFCO is proven by ferroelectric and magnetic
measurements showing that the films exhibit ferroelectric and magnetic
hysteresis at room temperature. In addition, local piezoelectric measurements
carried out using piezoresponse force microscopy (PFM) show the presence of
ferroelectric domains and their switching at the sub-micron scale.Comment: Accepted for publication in Philosophical Magazine Letter
Observation of an Exotic Baryon in Exclusive Photoproduction from the Deuteron
In an exclusive measurement of the reaction , a
narrow peak that can be attributed to an exotic baryon with strangeness
is seen in the invariant mass spectrum. The peak is at
GeV/c with a measured width of 0.021 GeV/c FWHM, which is largely
determined by experimental mass resolution. The statistical significance of the
peak is . The mass and width of the observed peak are
consistent with recent reports of a narrow baryon by other experimental
groups.Comment: 5 pages, 5 figure
Measurement of Beam-Spin Asymmetries for Deep Inelastic Electroproduction
We report the first evidence for a non-zero beam-spin azimuthal asymmetry in
the electroproduction of positive pions in the deep-inelastic region. Data have
been obtained using a polarized electron beam of 4.3 GeV with the CLAS detector
at the Thomas Jefferson National Accelerator Facility (JLab). The amplitude of
the modulation increases with the momentum of the pion relative to
the virtual photon, , with an average amplitude of for range.Comment: 5 pages, RevTEX4, 3 figures, 2 table
Risk groups defined by Recursive Partitioning Analysis of patients with colorectal adenocarcinoma treated with colorectal resection
<p>Abstract</p> <p>Background</p> <p>To define different prognostic groups of surgical colorectal adenocarcinoma patients derived from recursive partitioning analysis (RPA).</p> <p>Methods</p> <p>Ten thousand four hundred ninety four patients with colorectal adenocarcinoma underwent colorectal resection from Taiwan Cancer Database during 2003 to 2005 were included in this study. Exclusion criteria included those patients with stage IV disease or without number information of lymph nodes. For the definition of risk groups, the method of classification and regression tree was performed. Main primary outcome was 5-year cancer-specific survival.</p> <p>Results</p> <p>We identified six prognostic factors for cancer-specific survival, resulting in seven terminal nodes. Four risk groups were defined as following: Group 1 (mild risk, 1,698 patients), Group 2 (moderate risk, 3,129 patients), Group 3 (high risk, 4,605 patients) and Group 4 (very high risk, 1,062 patients). The 5-year cancer-specific survival for Group 1, 2, 3, and 4 was 86.6%, 62.7%, 55.9%, and 36.6%, respectively (p < 0.001). Hazard ratio of death was 2.13, 5.52 and 10.56 (95% confidence interval 1.74-2.60, 4.58-6.66 and 8.66-12.9, respectively) times for Group 2, 3, and 4 as compared to Group 1. The predictive capability of these grouping was also similar in terms of overall and progression-free survival.</p> <p>Conclusion</p> <p>The use of RPA offered an alternative grouping method that could predict the survival of patients who underwent surgery for colorectal adenocarcinoma.</p
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