554 research outputs found
Enrichment for chemoresistant ovarian cancer stem cells from human cell lines
Cancer stem cells (CSCs) are defined as a subset of slow cycling and undifferentiated cells that divide asymmetrically to generate highly proliferative, invasive, and chemoresistant tumor cells. Therefore, CSCs are an attractive population of cells to target therapeutically. CSCs are predicted to contribute to a number of types of malignancies including those in the blood, brain, lung, gastrointestinal tract, prostate, and ovary. Isolating and enriching a tumor cell population for CSCs will enable researchers to study the properties, genetics, and therapeutic response of CSCs. We generated a protocol that reproducibly enriches for ovarian cancer CSCs from ovarian cancer cell lines (SKOV3 and OVCA429). Cell lines are treated with 20 µM cisplatin for 3 days. Surviving cells are isolated and cultured in a serum-free stem cell media containing cytokines and growth factors. We demonstrate an enrichment of these purified CSCs by analyzing the isolated cells for known stem cell markers Oct4, Nanog, and Prom1 (CD133) and cell surface expression of CD177 and CD133. The CSCs exhibit increased chemoresistance. This method for isolation of CSCs is a useful tool for studying the role of CSCs in chemoresistance and tumor relapse
Evaluation of Trends in Diabetes Care in a Patient-centered Medical Home
Background: The patient-centered medical home (PCMH) is a model used in primary care to achieve effective management of chronic diseases. The Augusta University Health Family Medicine Center (AUFMC), a PCMH recognized by the National Committee for Quality Assurance, has implemented strategies to manage its patient population with diabetes. The present study evaluated the effects of these interventions through trend analysis of selected diabetic core measures by use of a qualified clinical data registry, the Practice Partner Research Network.
Methods: For this retrospective study, de-identified data were abstracted for adult patients with diabetes for the period of 2013-2015. Process and outcome measures were determined for selected diabetic core measures, based on the 2015 American Diabetes Association and Physician Quality Reporting System of the Centers for Medicaid and Medicare (CMS). These measures included glycated hemoglobin (HbA1c), blood pressure (BP), low-density lipoprotein cholesterol (LDL), urine microalbumin (Um), diabetic foot and eye exams, and influenza and pneumococcal vaccinations. These values were analyzed by the CochranArmitage test for trends over time to determine the proportions of patients at the recommended goals.
Results: Over time, there were increasing trends for patients who were at the goals for frequencies of HbA1c, Um, LDL, pneumococcal vaccinations, and diabetic retinal exams.
Conclusions: Since AUFMC achieved PCMH recognition status, efforts to improve the management of patients with diabetes have yielded positive outcomes and valuable lessons. Areas of strength include utilization of the diabetes registry, education by regular providers, tailored use of electronic health records for patient education and physician documentation, and appropriate utilization of all team members. Trend analysis indicated that targeted diabetic interventions contributed to improved outcomes in selected diabetic core measures
Paper Session I-D - An Interdisciplinary Student Payload to Perform Space Based Remote Sensing and to Measure Microgravity and Radiation Effects
Broward Community College and Brevard Community College with support from the Boeing Company-KSC, the Florida Space Institute, Texas A&M University and the Association of Small Payload Researchers (ASPR) will fly 3 remote sensing, 3 microgravity 2 radiation measurement experiments and 1 genotoxicology experiment in a Get Away Special (GAS) container through NASA’s GAS payload program. Students from fields as diverse as Chemistry, Biochemistry, Physics, Electrical, Computer and Mechanical Engineering, Astronomy, Marine Science, and Environmental Science will benefit from involvement in every level of design, fabrication, testing, calibration, and data analysis.
Three earth viewing remote sensing experiments will include a hyperspectral imaging holographic Fourier transform spectrometer, a high radiometric accuracy narrow band 4 channel discrete radiometer, and a 3 channel high spatial resolution imager.
Three microgravity experiments involve crystal growth: Calcium Tartrate crystals will be grown using a gel and diffusion method. Carbon dioxide will be combined with dimethylamine to form crystals. CuInSe thin films will be electro-deposited from aqueous solution.
Three radiation experiments include: A genotoxicology experiment to determine the degree to which DNA from man, chicken, fish, and plants, is damaged by exposure to cosmic radiation. Cosmic ray background intensity will be monitored using a standard Geiger tube. A separate module will record the path and intensity of cosmic rays as they pass through shielded photographic emulsions.
The importance of interdisciplinary training is fundamental to this payload and to the teaching of the natural sciences. This innovative student oriented project will payoff not only in new science data, but also in accomplishing training for the next generation of environmental and space scientists
Dications of 3-Phenyl-indenylidene Dibenzo[ a.d ]cycloheptene: The Role of Charge in the Antiaromaticity of Cationic Systems
Dications of 9-(3-phenyl-1H-inden-1-ylidene)-5H-dibenzo[a,d]cycloheptene, 52+, were prepared by oxidation with SbF5 in SO2ClF, and their magnetic behavior was compared to dications of 9-(3-phenyl-1H-inden-1-ylidene)-9H-fluorene, 22+. The good correlation between the experimental 1H NMR shifts for the dications that were oxidized cleanly and the chemical shifts calculated by the GAIO method supported the use of the nucleus independent chemical shifts, NICS, to evaluate the antiaromaticity of the indenyl systems of 22+/52+ and their unsubstituted parent compounds, 62+ and 72+, as well as the antiaromaticity of the fluorenyl system of 22+/72+ and the aromaticity of the dibenzotropylium system of 52+/62+. Antiaromaticity was shown to be directly related to the amount of charge in the antiaromatic systems, with the antiaromatic systems more responsive to changes in the calculated NBO charge than the aromatic systems. The antiaromaticity was also shown to be directly related to the amount of delocalization in the ring system. The aromaticity of the dibenzotropylium system was much less responsive to changes in the amount of charge in the tropylium system, because the aromatic system was much more completely delocalized. Thus, antiaromatic species are more sensitive probes of delocalization than aromatic ones
Differential expression analysis with global network adjustment
<p>Background: Large-scale chromosomal deletions or other non-specific perturbations of the transcriptome can alter the expression of hundreds or thousands of genes, and it is of biological interest to understand which genes are most profoundly affected. We present a method for predicting a gene’s expression as a function of other genes thereby accounting for the effect of transcriptional regulation that confounds the identification of genes differentially expressed relative to a regulatory network. The challenge in constructing such models is that the number of possible regulator transcripts within a global network is on the order of thousands, and the number of biological samples is typically on the order of 10. Nevertheless, there are large gene expression databases that can be used to construct networks that could be helpful in modeling transcriptional regulation in smaller experiments.</p>
<p>Results: We demonstrate a type of penalized regression model that can be estimated from large gene expression databases, and then applied to smaller experiments. The ridge parameter is selected by minimizing the cross-validation error of the predictions in the independent out-sample. This tends to increase the model stability and leads to a much greater degree of parameter shrinkage, but the resulting biased estimation is mitigated by a second round of regression. Nevertheless, the proposed computationally efficient “over-shrinkage” method outperforms previously used LASSO-based techniques. In two independent datasets, we find that the median proportion of explained variability in expression is approximately 25%, and this results in a substantial increase in the signal-to-noise ratio allowing more powerful inferences on differential gene expression leading to biologically intuitive findings. We also show that a large proportion of gene dependencies are conditional on the biological state, which would be impossible with standard differential expression methods.</p>
<p>Conclusions: By adjusting for the effects of the global network on individual genes, both the sensitivity and reliability of differential expression measures are greatly improved.</p>
The fidelity of DNA replication, particularly on GC-rich templates, is reduced by defects of the Fe-S cluster in DNA polymerase δ
Iron-sulfur clusters (4Fe-4S) exist in many enzymes concerned with DNA replication and repair. The contribution of these clusters to enzymatic activity is not fully understood. We identified the MET18 (MMS19) gene of Saccharomyces cerevisiae as a strong mutator on GC-rich genes. Met18p is required for the efficient insertion of iron-sulfur clusters into various proteins. met18 mutants have an elevated rate of deletions between short flanking repeats, consistent with increased DNA polymerase slippage. This phenotype is very similar to that observed in mutants of POL3 (encoding the catalytic subunit of Pol δ) that weaken binding of the iron-sulfur cluster. Comparable mutants of POL2 (Pol ϵ) do not elevate deletions. Further support for the conclusion that met18 strains result in impaired DNA synthesis by Pol δ are the observations that Pol δ isolated from met18 strains has less bound iron and is less processive in vitro than the wild-type holoenzyme
Absence of Scaling in the Integer Quantum Hall Effect
We have studied the conductivity peak in the transition region between the
two lowest integer Quantum Hall states using transmission measurements of edge
magnetoplasmons. The width of the transition region is found to increase
linearly with frequency but remains finite when extrapolated to zero frequency
and temperature. Contrary to prevalent theoretical pictures, our data does not
show the scaling characteristics of critical phenomena.These results suggest
that a different mechanism governs the transition in our experiment.Comment: Minor changes and new references include
Dream capitalism
John Tomasi’s Free Market Fairness represents an heroic attempt to bridge the gap between Rawlsian ‘high liberals’ and the advocates of classical liberalism/contemporary libertarianism. I argue that Tomasi’s project fails, above all because it cannot give a compelling account of contemporary (American) capitalism or of its capacity to deliver free market fairness
Structure and Functions of Pediatric Aerodigestive Programs: A Consensus Statement
Aerodigestive programs provide coordinated interdisciplinary care to pediatric patients with complex congenital or acquired conditions affecting breathing, swallowing, and growth. Although there has been a proliferation of programs, as well as national meetings, interest groups and early research activity, there is, as of yet, no consensus definition of an aerodigestive patient, standardized structure, and functions of an aerodigestive program or a blueprint for research prioritization. The Delphi method was used by a multidisciplinary and multi-institutional panel of aerodigestive providers to obtain consensus on 4 broad content areas related to aerodigestive care: (1) definition of an aerodigestive patient, (2) essential construct and functions of an aerodigestive program, (3) identification of aerodigestive research priorities, and (4) evaluation and recognition of aerodigestive programs and future directions. After 3 iterations of survey, consensus was obtained by either a supermajority of 75% or stability in median ranking on 33 of 36 items. This included a standard definition of an aerodigestive patient, level of participation of specific pediatric disciplines in a program, essential components of the care cycle and functions of the program, feeding and swallowing assessment and therapy, procedural scope and volume, research priorities and outcome measures, certification, coding, and funding. We propose the first consensus definition of the aerodigestive care model with specific recommendations regarding associated personnel, infrastructure, research, and outcome measures. We hope that this may provide an initial framework to further standardize care, develop clinical guidelines, and improve outcomes for aerodigestive patients
Precise Quantitation of the Latent HIV-1 Reservoir: Implications for Eradication Strategies
The quantitative viral outgrowth assay (QVOA) provides a precise minimal estimate of the reservoir of resting CD4+ T-cell infection (resting cell infection [RCI]). However, the variability of RCI over time during antiretroviral therapy (ART), relevant to assess potential effects of latency-reversing agents or other interventions, has not been fully described. We performed QVOA on resting CD4+ T cells obtained via leukapheresis from 37 human immunodeficiency virus (HIV)–infected patients receiving stable suppressive ART for a period of 6 years. Patients who started ART during acute (n = 17) or chronic (n = 20) HIV infection were studied once HIV RNA levels were 6-fold were rare. We suggest that a 6-fold decline is a relevant threshold to reliably identify effects of antilatency interventions on RCI
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