554 research outputs found

    Eradication of chronic myeloid leukemia stem cells: a novel mathematical model predicts no therapeutic benefit of adding G-CSF to imatinib

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    Imatinib mesylate induces complete cytogenetic responses in patients with chronic myeloid leukemia (CML), yet many patients have detectable BCR-ABL transcripts in peripheral blood even after prolonged therapy. Bone marrow studies have shown that this residual disease resides within the stem cell compartment. Quiescence of leukemic stem cells has been suggested as a mechanism conferring insensitivity to imatinib, and exposure to the Granulocyte-Colony Stimulating Factor (G-CSF), together with imatinib, has led to a significant reduction in leukemic stem cells in vitro. In this paper, we design a novel mathematical model of stem cell quiescence to investigate the treatment response to imatinib and G-CSF. We find that the addition of G-CSF to an imatinib treatment protocol leads to observable effects only if the majority of leukemic stem cells are quiescent; otherwise it does not modulate the leukemic cell burden. The latter scenario is in agreement with clinical findings in a pilot study administering imatinib continuously or intermittently, with or without G-CSF (GIMI trial). Furthermore, our model predicts that the addition of G-CSF leads to a higher risk of resistance since it increases the production of cycling leukemic stem cells. Although the pilot study did not include enough patients to draw any conclusion with statistical significance, there were more cases of progression in the experimental arms as compared to continuous imatinib. Our results suggest that the additional use of G-CSF may be detrimental to patients in the clinic

    Prolonged treatment with pimelic o-aminobenzamide HDAC inhibitors ameliorates the disease phenotype of a Friedreich ataxia mouse model

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    NOTICE: this is the author’s version of a work that was accepted for publication in Neurobiology of Disease. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication.Friedreich ataxia (FRDA) is an inherited neurodegenerative disorder caused by GAA repeat expansion within the FXN gene, leading to epigenetic changes and heterochromatin-mediated gene silencing that result in a frataxin protein deficit. Histone deacetylase (HDAC) inhibitors, including pimelic o-aminobenzamide compounds 106, 109 and 136, have previously been shown to reverse FXN gene silencing in short-term studies of FRDA patient cells and a knock-in mouse model, but the functional consequences of such therapeutic intervention have thus far not been described. We have now investigated the long-term therapeutic effects of 106, 109 and 136 in our GAA repeat expansion mutation-containing YG8R FRDA mouse model. We show that there is no overt toxicity up to 5 months of treatment and there is amelioration of the FRDA-like disease phenotype. Thus, while the neurological deficits of this model are mild, 109 and 106 both produced an improvement of motor coordination, whereas 109 and 136 produced increased locomotor activity. All three compounds increased global histone H3 and H4 acetylation of brain tissue, but only 109 significantly increased acetylation of specific histone residues at the FXN locus. Effects on FXN mRNA expression in CNS tissues were modest, but 109 significantly increased frataxin protein expression in brain tissue. 109 also produced significant increases in brain aconitase enzyme activity, together with reduction of neuronal pathology of the dorsal root ganglia (DRG). Overall, these results support further assessment of HDAC inhibitors for treatment of Friedreich ataxia.This work was supported by Repligen Corporation; Muscular Dystrophy Association (MDA) USA; Ataxia UK; Friedreich's Ataxia Research Alliance (FARA); GoFAR; and the Wellcome Trust [089757]

    Land Cover Trends Dataset, 1973–2000

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    The U.S. Geological Survey Land Cover Trends Project is releasing a 1973–2000 time-series land-use/land-cover dataset for the conterminous United States. The dataset contains 5 dates of land-use/land-cover data for 2,688 sample blocks randomly selected within 84 ecological regions. The nominal dates of the land-use/land-cover maps are 1973, 1980, 1986, 1992, and 2000. The land-use/land-cover maps were classified manually from Landsat Multispectral Scanner, Thematic Mapper, and Enhanced Thematic Mapper Plus imagery using a modified Anderson Level I classification scheme. The resulting land-use/land-cover data has a 60-meter resolution and the projection is set to Albers Equal-Area Conic, North American Datum of 1983. The files are labeled using a standard file naming convention that contains the number of the ecoregion, sample block, and Landsat year. The downloadable files are organized by ecoregion, and are available in the ERDAS IMAGINETM (.img) raster file format

    Health First: An evidence-based alcohol strategy for the UK

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    Alcohol is taken for granted in the UK today. It is easy to get hold of, increasingly affordable, advertised everywhere and accepted by many as an integral part of daily life. Yet, despite this, the great majority of the population recognise the harm that alcohol causes. They believe that drinking damages health, drives anti social behaviour, harms children and families and creates huge costs for the NHS and the Police. They are right. Every year in the UK, there are thousands of deaths and over a million hospital admissions related to drinking. More than two in five (44%) violent crimes are committed under the influence of alcohol, as are 37% of domesti c violence incidents. One fifth of all violent crime occurs in or near pubs and clubs and 45% of adults avoid town centres at night because of drunken behaviour. The personal, social and economic cost of alcohol has been estimated to be up to £55bn for England and £7.5bn for Scotland. None of this should be taken for granted. The impact of drinking on public health and community safety is so great that radical steps are needed to change our relationship with alcohol. We need to imagine a society where low or no alcohol consumpti on is the norm, drunkenness is socially unacceptable and town centres are safe and welcoming places for everyone to use. Our vision is for a safer, healthier and happier world where the harm caused by alcohol is minimised. This vision is achievable. But only if we tackle the primary drivers of alcohol consumption. The evidence is clear: the most effective way to reduce the harm from alcohol is to reduce the affordability, availability and attractiveness of alcohol products. It is not enough to limit the damage once people are drunk, dependent, ill or dying. We need to intervene earlier in order to reduce consumption across the entire population. The tools are available. The ‘four Ps' of the marketing mix - price, product, promotion and place - are used by alcohol producers and retailers to increase their sales of alcohol. They can also be used by government to reduce alcohol sales, alcohol consumption and alcohol-related harm. Alcohol taxes are an effective public health measure as they raise prices and suppress demand. However, if they do not keep pace with both inflation and incomes, alcohol products will become more affordable over time. This has been the case in the UK. Deep discounting by retailers has also driven down the price of alcohol and encouraged heavy drinkers to maintain dangerous levels of consumption. These problems need to be tackled by a combinati on of more effective fiscal policy and controls on pricing and discounting. Alcohol products are an extraordinary anomaly. Unlike most food products, they are both remarkably harmful and excepti onally lightly regulated. As with other toxic products, the product label ought to communicate the content of the product and the risks of its consumpti on. Regulation should drive out products that appeal to young people while also incentivising the development and sale of lower strength products. The pervasive marketing of alcohol products in the UK is indefensible. Current restrictions are woefully inadequate: children and young people are regularly exposed to alcohol adverti sing in both old and new media. Only a complete ban on all alcohol advertising and sponsorship will make a lasting diff erence. Licensing practice in the UK is out of date. The focus on pubs and bars has allowed shops and supermarkets to become the dominant players in alcohol sales. Consequently, alcohol is now more available than it has ever been. This has driven pre-loading: getting drunk on cheap, shop-bought alcohol before heading out to late-opening night life. Licensing must focus on public health and seek to control the overall availability of alcohol as well as the effects of drunkenness. Beyond these populati on-level approaches, many more targeted measures are needed to reduce alcohol-related harm. Early interventi on by health and social care professionals is an important and underexploited opportunity to prevent problems developing. Stronger drink driving measures are also required. All these measures are needed. Together, they provide a template for an integrated and comprehensive strategy to tackle the harm from alcohol in the UK.Additional co-authors: Gerry McElwee, Dr Kieran Moriarty CBE, Dr Robin Purshouse, Dr Peter Rice, Alison Rogers, George Roycroft , Chit Selvarajah, Don Shenker, Eric Appleby, Dr Nick Sheron, and Colin Shevill

    Multistate Comparison of Attractants for Monitoring Drosophila suzukii (Diptera: Drosophilidae) in Blueberries and Caneberries

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    Drosophila suzukii Matsumara, also referred to as the spotted wing drosophila, has recently expanded its global range with significant consequences for its primary host crops: blueberries, blackberries, raspberries, cherries, and strawberries. D. suzukii populations can increase quickly, and their infestation is difficult to predict and prevent. The development of effective tools to detect D. suzukii presence in new areas, to time the beginning of activity within a crop, to track seasonal activity patterns, and to gauge the effectiveness of management efforts has been a key research goal. We compared the efficiency, selectivity, and relationship to fruit infestation of a range of commonly used homemade baits and a synthetic formulated lure across a wide range of environments in 10 locations throughout the United States. Several homemade baits were more efficient than apple cider vinegar, a commonly used standard, and a commercially formulated lure was, in some configurations and environments, comparable with the most effective homemade attractant as well as potentially more selective. All alternative attractants also captured flies between 1 and 2 wk earlier than apple cider vinegar, and detected the presence of D. suzukii prior to the development of fruit infestation. Over half the Drosophila spp. flies captured in traps baited with any of the attractants were not D. suzukii, which may complicate their adoption by nonexpert users. The alternative D. suzukii attractants tested are improvement on apple cider vinegar and may be useful in the development of future synthetic lure

    Sequence-based prediction for vaccine strain selection and identification of antigenic variability in foot-and-mouth disease virus

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    Identifying when past exposure to an infectious disease will protect against newly emerging strains is central to understanding the spread and the severity of epidemics, but the prediction of viral cross-protection remains an important unsolved problem. For foot-and-mouth disease virus (FMDV) research in particular, improved methods for predicting this cross-protection are critical for predicting the severity of outbreaks within endemic settings where multiple serotypes and subtypes commonly co-circulate, as well as for deciding whether appropriate vaccine(s) exist and how much they could mitigate the effects of any outbreak. To identify antigenic relationships and their predictors, we used linear mixed effects models to account for variation in pairwise cross-neutralization titres using only viral sequences and structural data. We identified those substitutions in surface-exposed structural proteins that are correlates of loss of cross-reactivity. These allowed prediction of both the best vaccine match for any single virus and the breadth of coverage of new vaccine candidates from their capsid sequences as effectively as or better than serology. Sub-sequences chosen by the model-building process all contained sites that are known epitopes on other serotypes. Furthermore, for the SAT1 serotype, for which epitopes have never previously been identified, we provide strong evidence - by controlling for phylogenetic structure - for the presence of three epitopes across a panel of viruses and quantify the relative significance of some individual residues in determining cross-neutralization. Identifying and quantifying the importance of sites that predict viral strain cross-reactivity not just for single viruses but across entire serotypes can help in the design of vaccines with better targeting and broader coverage. These techniques can be generalized to any infectious agents where cross-reactivity assays have been carried out. As the parameterization uses pre-existing datasets, this approach quickly and cheaply increases both our understanding of antigenic relationships and our power to control disease

    Quantum Kinetic Theory I: A Quantum Kinetic Master Equation for Condensation of a weakly interacting Bose gas without a trapping potential

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    A Quantum Kinetic Master Equation (QKME) for bosonic atoms is formulated. It is a quantum stochastic equation for the kinetics of a dilute quantum Bose gas, and describes the behavior and formation of Bose condensation. The key assumption in deriving the QKME is a Markov approximation for the atomic collision terms. In the present paper the basic structure of the theory is developed, and approximations are stated and justified to delineate the region of validity of the theory. Limiting cases of the QKME include the Quantum Boltzmann master equation and the Uehling-Uhlenbeck equation, as well as an equation analogous to the Gross-Pitaevskii equation.Comment: 37 pages, 4 figure

    Use of Pharmacoeconomics Information—Report of the ISPOR Task Force on Use of Pharmacoeconomic/Health Economic Information in Health-Care Decision Making

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    Objectives: Despite the growing number of pharmacoeconomic (PE)/health economic (HE) studies, very little is known about their use by decision makers. The objectives of the Task Force were to ensure that the good research practices of PE/HE studies pay attention to the needs of health-care decision makers and to develop a “toolbox” for the health-care decision maker wanting to interpret and use PE/HE studies. Methods: The membership of the Task Force consisted of individuals involved in making decisions about the availability or use of medicines and researchers into the use of economic evaluations. The group communicated by E-mail and face-to-face meetings. A literature review of decision makers’ attitudes toward PE/HE studies and published economic evaluation guidelines was undertaken. In addition, a focus group discussion was held with opinion leaders in managed care pharmacy. Results: The literature review identified 16 surveys of decision makers’ attitudes toward PE/HE studies and 15 published guidelines that outlined reporting requirements for economic evaluations. These were reviewed and classified. Based on the published literature and comments from decision makers, seven additional reporting requirements for studies were specified. Conclusions: While the Task Force's additional reporting requirements may be helpful to decision makers, they raise a number of issues. These include the feasibility of meeting the additional requirements, whether decision makers should receive more education in economic evaluation, and whether there should be more study of health-care decision-making procedures themselves.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73067/1/j.1524-4733.2003.64245.x.pd
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