523 research outputs found
The ATM and ATR inhibitors CGK733 and caffeine suppress cyclin D1 levels and inhibit cell proliferation
The ataxia telangiectasia mutated (ATM) and the ATM- related (ATR) kinases play a central role in facilitating the resistance of cancer cells to genotoxic treatment regimens. The components of the ATM and ATR regulated signaling pathways thus provide attractive pharmacological targets, since their inhibition enhances cellular sensitivity to chemo- and radiotherapy. Caffeine as well as more specific inhibitors of ATM (KU55933) or ATM and ATR (CGK733) have recently been shown to induce cell death in drug-induced senescent tumor cells. Addition of these agents to cancer cells previously rendered senescent by exposure to genotoxins suppressed the ATM mediated p21 expression required for the survival of these cells. The precise molecular pharmacology of these agents however, is not well characterized. Herein, we report that caffeine, CGK733, and to a lesser extent KU55933, inhibit the proliferation of otherwise untreated human cancer and non-transformed mouse fibroblast cell lines. Exposure of human cancer cell lines to caffeine and CGK733 was associated with a rapid decline in cyclin D1 protein levels and a reduction in the levels of both phosphorylated and total retinoblastoma protein (RB). Our studies suggest that observations based on the effects of these compounds on cell proliferation and survival must be interpreted with caution. The differential effects of caffeine/CGK733 and KU55933 on cyclin D1 protein levels suggest that these agents will exhibit dissimilar molecular pharmacological profiles
DNA resection in eukaryotes: deciding how to fix the break
DNA double-strand breaks are repaired by different mechanisms, including homologous
recombination and nonhomologous end-joining. DNA-end resection, the first step in
recombination, is a key step that contributes to the choice of DSB repair. Resection, an
evolutionarily conserved process that generates single-stranded DNA, is linked to checkpoint
activation and is critical for survival. Failure to regulate and execute this process results in
defective recombination and can contribute to human disease. Here, I review recent findings on
the mechanisms of resection in eukaryotes, from yeast to vertebrates, provide insights into the
regulatory strategies that control it, and highlight the consequences of both its impairment and its
deregulation
Cellular Radiosensitivity: How much better do we understand it?
Purpose: Ionizing radiation exposure gives rise to a variety of lesions in DNA that result in genetic instability and potentially tumorigenesis or cell death. Radiation extends its effects on DNA by direct interaction or by radiolysis of H2O that generates free radicals or aqueous electrons capable of interacting with and causing indirect damage to DNA. While the various lesions arising in DNA after radiation exposure can contribute to the mutagenising effects of this agent, the potentially most damaging lesion is the DNA double strand break (DSB) that contributes to genome instability and/or cell death. Thus in many cases failure to recognise and/or repair this lesion determines the radiosensitivity status of the cell. DNA repair mechanisms including homologous recombination (HR) and non-homologous end-joining (NHEJ) have evolved to protect cells against DNA DSB. Mutations in proteins that constitute these repair pathways are characterised by radiosensitivity and genome instability. Defects in a number of these proteins also give rise to genetic disorders that feature not only genetic instability but also immunodeficiency, cancer predisposition, neurodegeneration and other pathologies.
Conclusions: In the past fifty years our understanding of the cellular response to radiation damage has advanced enormously with insight being gained from a wide range of approaches extending from more basic early studies to the sophisticated approaches used today. In this review we discuss our current understanding of the impact of radiation on the cell and the organism gained from the array of past and present studies and attempt to provide an explanation for what it is that determines the response to radiation
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The use of phylogeny to interpret cross-cultural patterns in plant use and guide medicinal plant discovery: an example from Pterocarpus (Leguminosae)
The study of traditional knowledge of medicinal plants has led to discoveries that have helped combat diseases and improve healthcare. However, the development of quantitative measures that can assist our quest for new medicinal plants has not greatly advanced in recent years. Phylogenetic tools have entered many scientific fields in the last two decades to provide explanatory power, but have been overlooked in ethnomedicinal studies. Several studies show that medicinal properties are not randomly distributed in plant phylogenies, suggesting that phylogeny shapes ethnobotanical use. Nevertheless, empirical studies that explicitly combine ethnobotanical and phylogenetic information are scarce.In this study, we borrowed tools from community ecology phylogenetics to quantify significance of phylogenetic signal in medicinal properties in plants and identify nodes on phylogenies with high bioscreening potential. To do this, we produced an ethnomedicinal review from extensive literature research and a multi-locus phylogenetic hypothesis for the pantropical genus Pterocarpus (Leguminosae: Papilionoideae). We demonstrate that species used to treat a certain conditions, such as malaria, are significantly phylogenetically clumped and we highlight nodes in the phylogeny that are significantly overabundant in species used to treat certain conditions. These cross-cultural patterns in ethnomedicinal usage in Pterocarpus are interpreted in the light of phylogenetic relationships.This study provides techniques that enable the application of phylogenies in bioscreening, but also sheds light on the processes that shape cross-cultural ethnomedicinal patterns. This community phylogenetic approach demonstrates that similar ethnobotanical uses can arise in parallel in different areas where related plants are available. With a vast amount of ethnomedicinal and phylogenetic information available, we predict that this field, after further refinement of the techniques, will expand into similar research areas, such as pest management or the search for bioactive plant-based compounds
Genetic differentiation across eastern Pacific oceanographic barriers in the threatened seahorse Hippocampus ingens
Measurement of D-s(+) and D-s(*+) production in B meson decays and from continuum e(+)e(-) annihilation at βs=10.6 GeV
This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APSNew measurements of Ds+ and Ds*+ meson production rates from B decays and from qqΜ
continuum events near the Ξ₯(4S) resonance are presented. Using 20.8 fb-1 of data on the Ξ₯(4S) resonance and 2.6 fb-1 off-resonance, we find the inclusive branching fractions B(BβDs+X)=(10.93Β±0.19Β±0.58Β±2.73)% and B(BβDs*+X)=(7.9Β±0.8Β±0.7Β±2.0)%, where the first error is statistical, the second is systematic, and the third is due to the Ds+βΟΟ+ branching fraction uncertainty. The production cross sections Ο(e+e-βDs+X)ΓB(Ds+βΟΟ+)=7.55Β±0.20Β±0.34pb and Ο(e+e-βDs*Β±X)ΓB(Ds+βΟΟ+)=5.8Β±0.7Β±0.5pb are measured at center-of-mass energies about 40 MeV below the Ξ₯(4S) mass. The branching fractions Ξ£B(BβDs(*)+D(*))=(5.07Β±0.14Β±0.30Β±1.27)% and Ξ£B(BβDs*+D(*))=(4.1Β±0.2Β±0.4Β±1.0)% are determined from the Ds(*)+ momentum spectra. The mass difference m(Ds+)-m(D+)=98.4Β±0.1Β±0.3MeV/c2 is also measured.This work was supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the Swiss NSF, A. P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation
Measurement of the branching fraction and CP content for the decay B(0) -> D(*+)D(*-)
This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2002 APS.We report a measurement of the branching fraction of the decay B0βD*+D*- and of the CP-odd component of its final state using the BABAR detector. With data corresponding to an integrated luminosity of 20.4ββfb-1 collected at the Ξ₯(4S) resonance during 1999β2000, we have reconstructed 38 candidate signal events in the mode B0βD*+D*- with an estimated background of 6.2Β±0.5 events. From these events, we determine the branching fraction to be B(B0βD*+D*-)=[8.3Β±1.6(stat)Β±1.2(syst)]Γ10-4. The measured CP-odd fraction of the final state is 0.22Β±0.18(stat)Β±0.03(syst).This work is supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the A.P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation
Weight outcomes audit in 1.3 million adults during their first 3 months' attendance in a commercial weight management programme
Background: Over sixty percent of adults in the UK are now overweight/obese. Weight management on a national scale requires behavioural and lifestyle solutions that are accessible to large numbers of people. Evidence suggests commercial weight management programmes help people manage their weight but there is little research examining those that pay to attend such programmes rather than being referred by primary care. The objective of this analysis was to evaluate the effectiveness of a UK commercial weight management programme in self-referred, fee-paying participants. Methods: Electronic weekly weight records were collated for self-referred, fee-paying participants of Slimming World groups joining between January 2010 and April 2012. This analysis reports weight outcomes in 1,356,105 adult, non-pregnant participants during their first 3 monthsβ attendance. Data were analysed by regression, ANOVA and for binomial outcomes, chi-squared tests using the R statistical program. Results: Mean (SD) age was 42.3 (13.6) years, height 1.65 m (0.08) and start weight was 88.4 kg (18.8). Mean start BMI was 32.6 kg/mΒ² (6.3 kg/mΒ²) and 5 % of participants were men. Mean weight change of all participants was β3.9 kg (3.6), percent weight change β4.4 (3.8), and BMI change was β1.4 kg/mΒ² (1.3). Mean attendance was 7.8 (4.3) sessions in their first 3 months. For participants attending at least 75 % of possible weekly sessions (nβ=β478,772), mean BMI change was β2.5 kg/mΒ² (1.3), weight change β6.8 kg (3.7) and percent weight change β7.5 % (3.5). Weight loss was greater in men than women absolutely (β6.5 (5.3) kg vs β3.8 (3.4) kg) and as a percentage (5.7 % (4.4) vs 4.3 % (3.7)), respectively. All comparisons were significant (pβ<β0.001). Level of attendance and percent weight loss in the first week of attendance together accounted for 55 % of the variability in weight lost during the study period. Conclusions: A large-scale commercial lifestyle-based weight management programme had a significant impact on weight loss outcomes over 3 months. Higher levels of attendance led to levels of weight loss known to be associated with significant clinical benefits, which on this scale may have an impact on public health
A pragmatic approach to resolving technological unfairness: The case of Nikeβs Vaporfly & Alphafly running footwear
Background
Technology is often introduced into sport to facilitate it or to improve human performance within it. On occasion, some forms of novel technology require regulation or prevention entirely to ensure that a sport remains fair and accessible. Recently, the Nike Vaporfly and Alphafly shoes have received some concerns over their appropriateness for use in competitive distance running.
Methods
This paper evaluates the use of these shoes against an existing framework for sports technology discourse and adopts a pragmatic approach to attempt to resolve them.
Results
It is proposed that the three concerns regarding cost, access and coercion cannot be ruled out but likely remain short term issues. As a result, it is proposed that these running shoes are acceptable forms of technology but that ongoing vigilance will be required as such technologies develop further in the future.
Conclusions
The Nike Vaporfly/Alphafly shoes do push the perceived acceptability of running shoes to the limits of the current sports regulations. However, the alleged gains have not manifested themselves to a level that could be considered excessive when reviewing historical performances or when evaluated against a set of well-cited criteria. The sport will need to adopt a stance of ongoing vigilance as such technologies continue to develop or be optimised in the future
Role of HDAC3 on p53 Expression and Apoptosis in T Cells of Patients with Multiple Sclerosis
Background: Histone deacetylase 3 (HDAC3) belongs to a family of proteins which plays an important role in protein acetylation, chromatin remodeling and transcription of genes, including those that are involved in cell proliferation and cell death. While increased expression of HDAC3 is seen in neoplastic cells, the role of HDAC3 in T cells and their role in autoimmune disease is not known. Methodology/Principal Findings: Applying Affymetrix GeneChip Human Gene 1.0 ST Array and the mixed effects model for gene set analysis, we compared gene expression profiles between multiple sclerosis (MS) patients and healthy controls (HC). Within the Apoptosis_GO gene set, the constitutive expression level of HDAC3 in peripheral blood mononuclear cell (PBMC) was significantly increased in MS patients when compared to controls. Following addition of trichostatin A (TSA), an inhibitor of HDAC3, we examined the expression of p53 by flow cytometry and p53 targeted genes by real time RT-PCR in MS and HC. Culture of PBMC with TSA resulted in increased expression of p53 in HC but not in MS patients. TSA treated T cells from MS patients also showed reduced sensitivity to apoptosis when compared to HC, which was independent of activation of p53 targeted pro-apoptotic genes. Conclusion/Significance: MS patients, when compared to controls, show an increased expression of HDAC3 and relative resistance to TSA induced apoptosis in T cells. Increased expression of HDAC3 in PBMC of MS patients may render putativ
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