246 research outputs found
Decreased expression of fecal miR-4478 and miR-1295b-3p in early-stage colorectal cancer
BACKGROUND: Colorectal cancer (CRC) is a major cause of cancer-related deaths world-wide. Detection of molecular markers in stool samples is a promising strategy for CRC screening. MicroRNAs (miRNAs) are short, non-coding RNA molecules that are commonly dysregulated in neoplasia. OBJECTIVE: The objective of this study was to evaluate the fecal miRNAs differentiation between early-stage CRC patients and healthy subjects. METHODS: Stool samples were collected from 40 patients with early stage (I, II) CRC and 16 healthy controls. RNA was extracted from all samples using miRNAeasy Mini Kits. MiRNA microarray expression profiling was performed with Agilent's miRNA Microarray system on 12 CRC and 8 normal stool samples. The expression levels of miR-4478 and miR-1295b-3p were determined by the SYBR Green miScript PCR system. RESULTS: In profiling study, we found 215 down-regulated miRNAs in CRC group. Furthermore, in validation study we found that the expression levels of fecal miR-4487 and miR-1295b-3p were significantly decreased in CRC patients compared to healthy controls. CONCLUSIONS: The expression of miR-4478 and miR-1295b-3p were significantly diminished in stool samples of CRC patients with early stage (I, II) in comparison with normal group. These miRNAs maybe use as potential non-invasive molecular markers for CRC diagnosis, but further studies are needed. © 2015 - IOS Press and the authors. All rights reserved
Downregulation of plasma MiR-142-3p and MiR-26a-5p in patients with colorectal carcinoma
Background: Colorectal cancer is one of the most commonly diagnosed cancers and cancer- related death worldwide. Identification of new specific biomarkers could be helpful to detection of this malignancy. Altered plasma microRNA expression has been identified in many cancers, including colorectal cancer. Objectives: The main objective of this study was to identify the circulating microRNAs with the most expression changes in colorectal cancer patients compared with neoplasm free healthy individuals. Materials and Methods: MicroRNA expression profiling was performed on plasma samples of 37 colorectal cancer patients and 8 normal subjects using microRNA microarray. Quantitative real-time reverse transcription polymerase chain reaction was used to validate the two selected altered microR NAs. Plasma samples from 61 colorectal cancer patients and 24 normal subjects were used in our validation study. Results: In profiling study we found a panel of six plasma microRNAs with significant downregulation. MicroRNA-142-3p and microRNA-26a-5p were selected and validated by polymerase chain reaction. Our results demonstrated that expression levels of plasma microRNA-142-3p and microRNA-26a-5p were significantly downregulated in patients with colorectal cancer when compared to control group. Conclusions: Our findings suggest that downregulation of plasma microRNA-142-3p and microRNA-26a-5p might serve as novel noninvasive biomarkers in the diagnosis of colorectal cancer, although more studies are needed to highlight the theoretical strengths. © 2015, Iranian Journal of Cancer Prevention
Magnetoencephalography—theory, instrumentation, and applications to noninvasive studies of the working human brain
Magnetoencephalography (MEG) is a noninvasive technique for investigating neuronal activity in the living human brain. The time resolution of the method is better than 1 ms and the spatial discrimination is, under favorable circumstances, 2-3 mm for sources in the cerebral cortex. In MEG studies, the weak 10 fT-1 pT magnetic fields produced by electric currents flowing in neurons are measured with multichannel SQUID (superconducting quantum interference device) gradiometers. The sites in the cerebral cortex that are activated by a stimulus can be found from the detected magnetic-field distribution, provided that appropriate assumptions about the source render the solution of the inverse problem unique. Many interesting properties of the working human brain can be studied, including spontaneous activity and signal processing following external stimuli. For clinical purposes, determination of the locations of epileptic foci is of interest. The authors begin with a general introduction and a short discussion of the neural basis of MEG. The mathematical theory of the method is then explained in detail, followed by a thorough description of MEG instrumentation, data analysis, and practical construction of multi-SQUID devices. Finally, several MEG experiments performed in the authors' laboratory are described, covering studies of evoked responses and of spontaneous activity in both healthy and diseased brains. Many MEG studies by other groups are discussed briefly as well.Peer reviewe
Monoethanolamine degradation rates in post-combustion CO2 capture plants with the capture of 100% of the added CO2
Residual emissions from post-combustion CO2 capture plants must be reduced to zero or recaptured from the atmosphere to be compatible with long-term climate change goals. For amine-based CO2 capture, increasing CO2 capture fractions requires maintaining sufficient driving force of absorption at the top of the absorber column by reducing lean solvent loadings. To produce low lean loadings without excessively increasing the specific thermal energy input, increased operational pressures are required in the CO2 stripper, inevitably leading to higher temperatures, which may increase the specific thermal degradation rate of the solvent. Concurrently, for solvents that react rapidly with dissolved O2, increased residence time in the absorber due to the increased packing heights also associated with high capture fractions may increase the specific oxidative degradation rate as the direct contact with O2 in the flue gas is extended. Through process modeling and the application of a newly developed monoethanolamine (MEA) degradation framework, we investigate the effect on solvent degradation rates of increasing CO2 capture rates up to those that result in no net CO2 addition to the atmosphere. We do this for three key energy-producing processes: a combined cycle gas turbine, an energy from waste facility, and a steam methane reformer. In a first-of-a-kind study, we demonstrate that for a 35 wt % MEA-based solvent under steady-state conditions, solvent degradation is predicted to increase by 24–138% as a result of decreasing lean loadings and increased absorber residence time (process modifications that are thought to be beneficial when increasing CO2 capture fractions) from 53 to 208 gMEA/tCO2 when a 95% CO2 gross capture fraction is achieved to 125–257 gMEA/tCO2 when 99.2–99.8% is achieved (i.e., when 100% of the added CO2 is captured). Further analysis provides evidence that process modifications, such as intercooling of the absorber column and reduced stripper sump residence times, may be useful in reducing the rates of solvent degradation, providing critical insights to future test campaigns and project developments. However, limitations of this study remain; the degradation framework provides the instantaneous predicted MEA consumption rate of the system at a point in time and does not consider the catalytic effects that many impurities present in an operation plant will have on the reactions, potentially impacting degradation rates. Nonetheless, this serves as the first step toward understanding the effect of increasing CO2 capture fractions in post-combustion CO2 capture plants. Long-term tests with appropriate solvent management practices are required to fully quantify solvent degradation rates when operating at 100% added CO2 capture fractions
Ploidy in bone marrow cells from healthy donors: a MAC (morphology antibody chromosomes) study
The ploidy of human bone marrow cells belonging to the megakaryocytic, granulocytic-monocytic and erythrocytic lineages was studied by in situ hybridization using the biotin-labelled Y chromosome-specific DNA probe pY431 and the chromosome 1-specific probe pUC1.77 on cells identified morphologically and immunologically by the MAC procedure. Cells of the granulocytic-monocytic and erythrocytic lineages were seen to be 2N in ploidy, whereas the ploidy of the megakaryocytic lineage ranged from 2N to 32N, with the ploidy classes 4N and 8N being predominant. The frequency of megakaryocytes with 2N chromosomes was also high.Facultad de Ciencias Naturales y Muse
CanGEM: mining gene copy number changes in cancer
The use of genome-wide and high-throughput screening methods on large sample sizes is a well-grounded approach when studying a process as complex and heterogeneous as tumorigenesis. Gene copy number changes are one of the main mechanisms causing cancerous alterations in gene expression and can be detected using array comparative genomic hybridization (aCGH). Microarrays are well suited for the integrative systems biology approach, but none of the existing microarray databases is focusing on copy number changes. We present here CanGEM (Cancer GEnome Mine), which is a public, web-based database for storing quantitative microarray data and relevant metadata about the measurements and samples. CanGEM supports the MIAME standard and in addition, stores clinical information using standardized controlled vocabularies whenever possible. Microarray probes are re-annotated with their physical coordinates in the human genome and aCGH data is analyzed to yield gene-specific copy numbers. Users can build custom datasets by querying for specific clinical sample characteristics or copy number changes of individual genes. Aberration frequencies can be calculated for these datasets, and the data can be visualized on the human genome map with gene annotations. Furthermore, the original data files are available for more detailed analysis. The CanGEM database can be accessed at http://www.cangem.org/
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