2,694 research outputs found
Comparison of effects of sleeve gastrectomy, duodenal-jejunal bypass and ileal transposition for the treatment of type II diabetes
This journal suppl. entitled: 2014 DDW AbstractThe SSAT’s 55th Annual Meeting took place during Digestive Disease Week 2014SSAT Poster Session (8215) - Stomach: Basic (I)BACKGROUND: Sleeve gastrectomy (SG), duodenal jejunal bypass (DJB) and ileal transposition (IT) have been reported to be effective for the treatment of T2DM. It is unknown which procedure has a stronger anti-diabetic effect. The purpose of this study was to compare the effectiveness of these novel procedures METHODS: SG, DJB, IT and ...postprin
Statistics of Gravitational Microlensing Magnification. I. Two-Dimensional Lens Distribution
(Abridged) In this paper we refine the theory of microlensing for a planar
distribution of point masses. We derive the macroimage magnification
distribution P(A) at high magnification (A-1 >> tau^2) for a low optical depth
(tau << 1) lens distribution by modeling the illumination pattern as a
superposition of the patterns due to individual ``point mass plus weak shear''
lenses. We show that a point mass plus weak shear lens produces an astroid-
shaped caustic and that the magnification cross-section obeys a simple scaling
property. By convolving this cross-section with the shear distribution, we
obtain a caustic-induced feature in P(A) which also exhibits a simple scaling
property. This feature results in a 20% enhancement in P(A) at A approx 2/tau.
In the low magnification (A-1 << 1) limit, the macroimage consists of a bright
primary image and a large number of faint secondary images formed close to each
of the point masses. Taking into account the correlations between the primary
and secondary images, we derive P(A) for low A. The low-A distribution has a
peak of amplitude ~ 1/tau^2 at A-1 ~ tau^2 and matches smoothly to the high-A
distribution. We combine the high- and low-A results and obtain a practical
semi-analytic expression for P(A). This semi-analytic distribution is in
qualitative agreement with previous numerical results, but the latter show
stronger caustic-induced features at moderate A for tau as small as 0.1. We
resolve this discrepancy by re-examining the criterion for low optical depth. A
simple argument shows that the fraction of caustics of individual lenses that
merge with those of their neighbors is approx 1-exp(-8 tau). For tau=0.1, the
fraction is surprisingly high: approx 55%. For the purpose of computing P(A) in
the manner we did, low optical depth corresponds to tau << 1/8.Comment: 35 pages, including 6 figures; uses AASTeX v4.0 macros; submitted to
Ap
BRCA1 positively regulates FOXO3 expression by restricting FOXO3 gene methylation and epigenetic silencing through targeting EZH2 in breast cancer.
BRCA1 mutation or depletion correlates with basal-like phenotype and poor prognosis in breast cancer but the underlying reason remains elusive. RNA and protein analysis of a panel of breast cancer cell lines revealed that BRCA1 deficiency is associated with downregulation of the expression of the pleiotropic tumour suppressor FOXO3. Knockdown of BRCA1 by small interfering RNA (siRNA) resulted in downregulation of FOXO3 expression in the BRCA1-competent MCF-7, whereas expression of BRCA1 restored FOXO3 expression in BRCA1-defective HCC70 and MDA-MB-468 cells, suggesting a role of BRCA1 in the control of FOXO3 expression. Treatment of HCC70 and MDA-MB-468 cells with either the DNA methylation inhibitor 5-aza-2'-deoxycitydine, the N-methyltransferase enhancer of zeste homologue 2 (EZH2) inhibitor GSK126 or EZH2 siRNA induced FOXO3 mRNA and protein expression, but had no effect on the BRCA1-competent MCF-7 cells. Chromatin immunoprecipitation (ChIP) analysis demonstrated that BRCA1, EZH2, DNMT1/3a/b and histone H3 lysine 27 trimethylation (H3K27me3) are recruited to the endogenous FOXO3 promoter, further advocating that these proteins interact to modulate FOXO3 methylation and expression. In addition, ChIP results also revealed that BRCA1 depletion promoted the recruitment of the DNA methyltransferases DNMT1/3a/3b and the enrichment of the EZH2-mediated transcriptional repressive epigenetic marks H3K27me3 on the FOXO3 promoter. Methylated DNA immunoprecipitation assays also confirmed increased CpG methylation of the FOXO3 gene on BRCA1 depletion. Analysis of the global gene methylation profiles of a cohort of 33 familial breast tumours revealed that FOXO3 promoter methylation is significantly associated with BRCA1 mutation. Furthermore, immunohistochemistry further suggested that FOXO3 expression was significantly associated with BRCA1 status in EZH2-positive breast cancer. Consistently, high FOXO3 and EZH2 mRNA levels were significantly associated with good and poor prognosis in breast cancer, respectively. Together, these data suggest that BRCA1 can prevent and reverse FOXO3 suppression via inhibiting EZH2 and, consequently, its ability to recruit the transcriptional repressive H3K27me3 histone marks and the DNA methylases DNMT1/3a/3b, to induce DNA methylation and gene silencing on the FOXO3 promoter
Endoplasmic reticulum chaperone prolyl 4-hydroxylase, beta polypeptide (P4HB) promotes malignant phenotypes in glioma via MAPK signaling
published_or_final_versio
The significance of proline-rich tyrosine kinase2 (Pyk2) on hepatocellular carcinoma progression and recurrence
Understanding the precise molecular mechanisms that trigger liver cancer cell migration and invasion could develop novel therapeutic strategies targeting cancer cell invasion to increase the sensitivity to current treatment modalities. In the current study, 49 patients with hepatocellular carcinoma (HCC) were included prospectively. Liver tumour and adjacent non-tumour tissues were detected for the expression of Proline-rich tyrosine kinase 2 (Pyk2), focal adhesion kinase (FAK), ezrin and fibronectin at protein and/or gene levels. Correlation between the expressions of Pyk2/FAK with the clinical pathological data was analysed. Protein expression of Pyk2 was also examined in a nude mice orthotopic liver tumour model with higher metastatic potential. There were 59% (29 out of 49) and 57% (28 out of 49) of HCC patients with higher levels of Pyk2 and FAK protein/gene expression, respectively. We observed a positive correlation between the protein and gene expression levels of Pyk2 and FAK (P=0.000, r=0.875). Overexpression of Pyk2 and FAK was significantly correlated with shorter disease-free survival. Patients with higher levels of Pyk2/FAK had larger tumour size and advanced Edmonson grading. In the animal studies, Pyk2 overexpression was found in infiltrative tumour cells and lung metastatic nodules. In conclusion, overexpression of Pyk2 and FAK was found in nearly 60% of HCC patients and was significantly correlated with poor prognosis. The significance of Pyk2 in HCC invasiveness was confirmed by animal studies. © 2007 Cancer Research UK.published_or_final_versio
FTY720 Suppresses Liver Tumor Metastasis by Reducing the Population of Circulating Endothelial Progenitor Cells
Background: Surgical procedures such as liver resection and liver transplantation are the first-line treatments for hepatocellular carcinoma (HCC) patients. However, the high incidence of tumor recurrence and metastasis after liver surgery remains a major problem. Recent studies have shown that hepatic ischemia-reperfusion (I/R) injury and endothelial progenitor cells (EPCs) contribute to tumor growth and metastasis. We aim to investigate the mechanism of FTY720, which was originally applied as an immunomodulator, on suppression of liver tumor metastasis after liver resection and partial hepatic I/R injury. Methodology/Principal Findings: An orthotopic liver tumor model in Buffalo rat was established using the hepatocellular carcinoma cell line McA-RH7777. Two weeks after orthotopic liver tumor implantation, the rats underwent liver resection for tumor-bearing lobe and partial hepatic I/R injury. FTY720 (2 mg/kg) was administered through the inferior caval vein before and after I/R injury. Blood samples were taken at days 0, 1, 3, 7, 14, 21 and 28 for detection of circulating EPCs (CD133+CD34+). Our results showed that intrahepatic and lung metastases were significantly inhibited together with less tumor angiogenesis by FTY720 treatment. The number of circulating EPCs was also significantly decreased by FTY720 treatment from day 7 to day 28. Hepatic gene expressions of CXCL10, VEGF, CXCR3, CXCR4 induced by hepatic I/R injury were down-regulated in the treatment group. Conclusions/Significance: FTY720 suppressed liver tumor metastasis after liver resection marred by hepatic I/R injury in a rat liver tumor model by attenuating hepatic I/R injury and reducing circulating EPCs. © 2012 Li et al.published_or_final_versio
Disorder-Induced Anomalous Kinetics in the Reaction
We address the two-dimensional bimolecular annihilation reaction in the presence of random impurities. Impurities with sufficiently
long-ranged interaction energies are known to lead to anomalous diffusion,
, in the absence of reaction. Applying
renormalization group theory to a field theoretic description of this reaction,
we find that this disorder also leads to anomalous kinetics in the long time
limit: . This kinetics results because the disorder
forces the system into the (sub)diffusion controlled regime, in which the
kinetics must become anomalous.Comment: REVTEX, 4 pages. More discussion added. To appear in Phys. Rev. E
(March, 1998
Compensated right ventricular function of the onset of pulmonary hypertension in a rat model depends on chamber remodeling and contractile augmentation.
Right-ventricular function is a good indicator of pulmonary arterial hypertension (PAH) prognosis; however, how the right ventricle (RV) adapts to the pressure overload is not well understood. Here, we aimed at characterizing the time course of RV early remodeling and discriminate the contribution of ventricular geometric remodeling and intrinsic changes in myocardial mechanical properties in a monocrotaline (MCT) animal model. In a longitudinal study of PAH, ventricular morphology and function were assessed weekly during the first four weeks after MCT exposure. Using invasive measurements of RV pressure and volume, heart performance was evaluated at end of systole and diastole to quantify contractility (end-systolic elastance) and chamber stiffness (end-diastolic elastance). To distinguish between morphological and intrinsic mechanisms, a computational model of the RV was developed and used to determine the level of prediction when accounting for wall masses and unloaded volume measurements changes. By four weeks, mean pulmonary arterial pressure and elastance rose significantly. RV pressures rose significantly after the second week accompanied by significant RV hypertrophy, but RV stroke volume and cardiac output were maintained. The model analysis suggested that, after two weeks, this compensation was only possible due to a significant increase in the intrinsic inotropy of RV myocardium. We conclude that this MCT-PAH rat is a model of RV compensation during the first month after treatment, where geometric remodeling on EDPVR and increased myocardial contractility on ESPVR are the major mechanisms by which stroke volume is preserved in the setting of elevated pulmonary arterial pressure. The mediators of this compensation might themselves promote longer-term adverse remodeling and decompensation in this animal model
MicroRNA expression, survival, and response to interferon in liver cancer
BACKGROUND: Hepatocellular carcinoma is a common and aggressive cancer that occurs mainly in men. We examined microRNA expression patterns, survival, and response to interferon alfa in both men and women with the disease. METHODS: We analyzed three independent cohorts that included a total of 455 patients with hepatocellular carcinoma who had undergone radical tumor resection between 1999 and 2003. MicroRNA-expression profiling was performed in a cohort of 241 patients with hepatocellular carcinoma to identify tumor-related microRNAs and determine their association with survival in men and women. In addition, to validate our findings, we used quantitative reverse-transcriptase-polymerase- chain-reaction assays to measure microRNAs and assess their association with survival and response to therapy with interferon alfa in 214 patients from two independent, prospective, randomized, controlled trials of adjuvant interferon therapy. RESULTS: In patients with hepatocellular carcinoma, the expression of miR-26a and miR-26b in nontumor liver tissue was higher in women than in men. Tumors had reduced levels of miR-26 expression, as compared with paired noncancerous tissues, which indicated that the level of miR-26 expression was also associated with hepatocellular carcinoma. Moreover, tumors with reduced miR-26 expression had a distinct transcriptomic pattern, and analyses of gene networks revealed that activation of signaling pathways between nuclear factor κB and interleukin-6 might play a role in tumor development. Patients whose tumors had low miR-26 expression had shorter overall survival but a better response to interferon therapy than did patients whose tumors had high expression of the microRNA. CONCLUSIONS: The expression patterns of microRNAs in liver tissue differ between men and women with hepatocellular carcinoma. The miR-26 expression status of such patients is associated with survival and response to adjuvant therapy with interferon alfa. Copyright © 2009 Massachusetts Medical Society. All rights reserved.published_or_final_versio
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