5,239 research outputs found
Altered expression of CD44 and DKK1 in the progression of Barrett's esophagus to esophageal adenocarcinoma
Barrett's esophagus (BE) is an acquired condition in which the normal lining of the esophagus is replaced by intestinal metaplastic epithelium. BE can evolve to esophageal adenocarcinoma (EAC) through low-grade dysplasia (LGD) and high-grade dysplasia (HGD). The only generally accepted marker for increased risk of EAC is the presence of HGD, diagnosed on endoscopic biopsies. More specific markers for the prediction of EAC risk are needed. A tissue microarray was constructed comprising tissue samples from BE, LGD, HGD, and EAC. Marker expression was studied by immunohistochemistry using antibodies against CD44, DKK1, CDX2, COX2, SOX9, OCT1, E-cadherin, and β-catenin. Immunostaining was evaluated semi-quantitatively. CD44 expression decreased in HGD and EAC relative to BE and LGD. DKK1 expression increased in HGD and EAC relative to BE and LDG. CDX2 expression increased in HGD but decreased in EAC. COX2 expression decreased in EAC, and SOX9 expression increased only in the upper crypt epithelial cells in HGD. E-cadherin expression decreased in EAC. Nuclear β-catenin was not significantly different between BE, LGD, and HGD. Loss of CD44 and gain of DKK1 expression characterizes progression from BE and LGD to HGD and EAC, and their altered expression might indicate an increased risk for developing an EAC. This observation warrants inclusion of these immunohistochemically detectable markers in a study with a long patient follow-u
Prognosis of stage II and III colon cancer treated with adjuvant 5-fluorouracil or FOLFIRI in relation to microsatellite status: results of the PETACC-3 trial†
We examined the effect of MSI status in a trial-based cohort of 1254 stage II and III colon cancer (CC) patients treated with 5-FU/LV or FOLFIRI. We confirm that for stage II CC MSI is strongly prognostic for RFS and OS. No significant differences were found between treatment arms. Adding irinotecan to 5-FU did not benefit MSI-H tumors. RFS was better for MSI-H CC both in the right and left colo
A Trade-Off Study Revealing Nested Timescales of Constraint
This study investigates human performance in a cyclic Fitts task at three different scales of observation, either in the presence (difficult condition) or in the absence (easy condition) of a speed–accuracy trade-off. At the fastest scale, the harmonicity of the back and forth movements, which reflects the dissipation of mechanical energy, was measured within the timeframe of single trials. At an intermediate scale, speed and accuracy measures were determined over a trial. The slowest scale pertains to the temporal structure of movement variability, which evolves over multiple trials. In the difficult condition, reliable correlations across each of the measures corroborated a coupling of nested scales of performance. Participants who predominantly emphasized the speed-side of the trade-off (despite the instruction to be both fast and accurate) produced more harmonic movements and clearer 1/f scaling in the produced movement time series, but were less accurate and produced more random variability in the produced movement amplitudes (vice versa for more accurate participants). This implied that speed–accuracy trade-off was accompanied by a trade-off between temporal and spatial streams of 1/f scaling, as confirmed by entropy measures. In the easy condition, however, no trade-offs nor couplings among scales of performance were observed. Together, these results suggest that 1/f scaling is more than just a byproduct of cognition. These findings rather support the claim that interaction-dominant dynamics constitute a coordinative basis for goal-directed behavior
Dual role of DNA methylation inside and outside of CTCF-binding regions in the transcriptional regulation of the telomerase hTERT gene
Expression of hTERT is the major limiting factor for telomerase activity. We previously showed that methylation of the hTERT promoter is necessary for its transcription and that CTCF can repress hTERT transcription by binding to the first exon. In this study, we used electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) to show that CTCF does not bind the methylated first exon of hTERT. Treatment of telomerase-positive cells with 5-azadC led to a strong demethylation of hTERT 5′-regulatory region, reactivation of CTCF binding and downregulation of hTERT. Although complete hTERT promoter methylation was associated with full transcriptional repression, detailed mapping showed that, in telomerase-positive cells, not all the CpG sites were methylated, especially in the promoter region. Using a methylation cassette assay, selective demethylation of 110 bp within the core promoter significantly increased hTERT transcriptional activity. This study underlines the dual role of DNA methylation in hTERT transcriptional regulation. In our model, hTERT methylation prevents binding of the CTCF repressor, but partial hypomethylation of the core promoter is necessary for hTERT expression
Relative Sea-Level Rise Projections and Flooding Scenarios for 2150 CE for the Island of Ustica (Southern Tyrrhenian Sea, Italy)
The island of Ustica (Italy) is constantly exposed to the effects of sea-level rise, which is threatening its coastal zone. With the aim of assessing the sea levels that are anticipated by 2150 CE under the climatic projections shown in the AR6 report from the IPCC, a detailed evaluation of potential coastal flooding under different climatic scenarios and the ongoing land subsidence has been carried out for three coastal zones. Scenarios are based on the determination of the current coastline position, a high-resolution digital terrain and marine model, and the SSP1-2.6, SSP3-7.0, and SSP5-8.5 climatic projections. Relative sea-level rise projections allowed the mapping of the potential inundated surfaces for 2030, 2050, 2100, and 2150. The results show rising sea levels for 2150, ranging from a minimum of 66 ± 40 cm (IPCC AR6 SSP2.6 scenario) to a maximum of 128 ± 52 cm (IPCC AR6 SSP8.5 scenario). In such conditions, considering the SSP8.5 scenario during storm surges with return times (RTs) of 1 and 100 years, the expected maximum wave run-up along the island may vary from 3 m (RT = 1) to 14 m (RT = 100), according to the coastal morphology. Our results show that adaptation and mitigation actions are required to protect the touristic and harbor installations of the island
Kalman filter density reconstruction in ICRH discharges on ASDEX Upgrade
Plasma density is one of the key quantities that need to be controlled in real-time as it scales directly with fusion power and, if left uncontrolled, density limits can be reached leading to a disruption. On ASDEX Upgrade (AUG), the real-time measurements are the line-integrated density, measured by the interferometers, and the average density derived from the bremsstrahlung measured by spectroscopy. For control, these measurements are used to reconstruct the radial density profile using an extended Kalman filter (EKF). However, in discharges where ion cyclotron resonance heating (ICRH) is used, the measurements from the interferometers are corrupted and the reconstructed density is false. In this paper, the existing EKF implementation is improved, implemented and experimentally verified on AUG. The new EKF includes a new particle transport model in the prediction model RAPDENS as well as a new representation of ionization and recombination. Furthermore, an algorithm was introduced that is capable of detecting the corrupt diagnostics; this algorithm is based on the rate of change of the innovation residual. The changes to the RAPDENS observer resulted in better density reconstruction in ICRH discharges where corrupt measurement occur. The new version has been implemented on the real-time control system at AUG and functions properly in ICRH discharges.</p
Cell Line Derived 5-FU and Irinotecan Drug-Sensitivity Profiles Evaluated in Adjuvant Colon Cancer Trial Data.
This study evaluates whether gene signatures for chemosensitivity for irinotecan and 5-fluorouracil (5-FU) derived from in vitro grown cancer cell lines can predict clinical sensitivity to these drugs.
To test if an irinotecan signature and a SN-38 signature could identify patients who benefitted from the addition of irinotecan to 5-FU, we used gene expression profiles based on cell lines and clinical tumor material. These profiles were applied to expression data obtained from pretreatment formalin fixed paraffin embedded (FFPE) tumor tissue from 636 stage III colon cancer patients enrolled in the PETACC-3 prospective randomized clinical trial. A 5-FU profile developed similarly was assessed by comparing the PETACC-3 cohort with a cohort of 359 stage II colon cancer patients who underwent surgery but received no adjuvant therapy.
There was no statistically significant association between the irinotecan or SN-38 profiles and benefit from irinotecan. The 5-FU sensitivity profile showed a statistically significant association with relapse free survival (RFS) (hazard ratio (HR) = 0.54 (0.41-0.71), p<1e-05) and overall survival (HR = 0.47 (0.34-0.63), p<1e-06) in the PETACC-3 subpopulation. The effect of the 5-FU profile remained significant in a multivariable Cox Proportional Hazards model, adjusting for several relevant clinicopathological parameters. No statistically significant effect of the 5-FU profile was observed in the untreated cohort of 359 patients (relapse free survival, p = 0.671).
The irinotecan predictor had no predictive value. The 5-FU predictor was prognostic in stage III patients in PETACC-3 but not in stage II patients with no adjuvant therapy. This suggests a potential predictive ability of the 5-FU sensitivity profile to identify colon cancer patients who may benefit from 5-FU, however, any biomarker predicting benefit for adjuvant 5-FU must be rigorously evaluated in independent cohorts. Given differences between the two study cohorts, the present results should be further validated
Immunohistochemical localization of hTERT protein in human tissues
Telomerase is a ribonucleoprotein complex mainly composed of a reverse transcriptase catalytic subunit (telomerase reverse transcriptase gene, hTERT) that copies a template region of its RNA subunit to the end of the telomere. For detecting telomerase activity in a tissue specimen the TRAP assay is a relatively sensitive and specific method, but it can be used only on fresh tissue extracts and offers no information at the single cell level. Immunohistochemistry (IHC) allows to detect hTERT protein expression at an individual cell level in human tissues. We have tested commercially available anti-hTERT antibodies in formalin-fixed and paraffin-embedded human tissues by IHC. Only one monoclonal antibody (NCL-hTERT; Novacastra) was sufficiently specific and this was applied to human tissues in which telomerase activity had been shown by TRAP assay and hTERT mRNA expression by RT-PCR. hTERT protein localized diffusely in the nucleoplasm and more intensely in the nucleoli of cancer cells and proliferating normal cells. Mitotic cells showed diffuse staining of the entire cell. Granular cytoplasmic staining was occasionally found in some tumor cells. In telomerase-positive tumors not all the tumor cells showed hTERT immunoreactivity. A significantly heterogeneous hTERT protein expression was observed in human tumor tissues. The hTERT immunostaining in fixed tissues was concordant with telomerase activity and hTERT mRNA expression in corresponding non-fixed samples. Quantitative RT-PCR of microdissected sections showed that hTERT mRNA expression was higher in cells with nuclear expression than in those with cytoplasmic expression. Double staining with the M30 antibody showed that a subpopulation of hTERT-negative cells is apoptotic. We conclude that: (1) hTERT protein can be detected by IHC in fixed human tissues, but the choice of the antibody, tissue processing, and reaction conditions are critical, (2) hTERT protein localizes in the nucleoplasm, more strongly in the nucleolus, and occasionally in the cytoplasm, (3) telomerase-positive tumors show significant heterogeneity of hTERT protein expression, and (4) a subpopulation of hTERT protein negative tumor cells is identified as apoptotic cell
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