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Search Results: 1 - 10 of 155293 matches for " Dominique Bégué "
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RNA editing in plant mitochondria, cytoplasmic male sterility and plant breeding.
Araya,Alexandre; Zabaleta,Eduardo; Blanc,Valérie; Bégu,Dominique; Hernould,Michel; Mouras,Armand; Litvak,Simon;
Electronic Journal of Biotechnology , 1998,
Abstract: rna editing in plant mitochondria is a post-transcriptional process involving the partial change of c residues into u. these c to u changes lead to the synthesis of proteins with an amino acid sequence different to that predicted from the gene. proteins produced from edited mrnas are more similar to those from organisms where this process is absent. this biochemical process involves cytidine deamination. the cytoplasmic male sterility (cms) phenotype generated by the incompatibility between the nuclear and the mitochondrial genomes is an important agronomical trait which prevents inbreeding and favors hybrid production. the hypothesis that rna editing leads to functional proteins has been proposed. this hypothesis was tested by constructing transgenic plants expressing a mitochondrial protein translated from unedited mrna. the transgenic "unedited" protein was addressed to the mitochondria leading to the appearance of mitochondrial dysfunction and generating the male sterile phenotype in transgenic tobacco plants. male sterile plants were also obtained by expressing specifically a bacterial ribonuclease in the anthers. the economical benefits of artificially engineered male-sterile plants or carrying the (native) spontaneous cms phenotype, implies the restoration to obtain fertile hybrids that will be used in agriculture. restoration to fertility of transgenic plants was obtained either by crossing male-sterile plants carrying the "unedited" mrna with plants carrying the same rna, but in the antisense orientation or, in the case of plants expresing the ribonuclease, by crossing male-sterile plants with plants expressing an inhibitor specific of this enzyme
Chronology of prescribing error during the hospital stay and prediction of pharmacist's alerts overriding: a prospective analysis
Thibaut Caruba, Isabelle Colombet, Florence Gillaizeau, Vanida Bruni, Virginie Korb, Patrice Prognon, Dominique Bégué, Pierre Durieux, Brigitte Sabatier
BMC Health Services Research , 2010, DOI: 10.1186/1472-6963-10-13
Abstract: We prospectively collected all medication order lines and prescribing errors during 18 days in 7 medical wards' using computerized physician order entry. We described and modelled the errors rate according to the chronology of hospital stay. We performed a classification and regression tree analysis to find which characteristics of alerts were predictive of their overriding (i.e. prescribing error repeated).12 533 order lines were reviewed, 117 errors (errors rate 0.9%) were observed and 51% of these errors occurred on the first day of the hospital stay. The risk of a prescribing error decreased over time. 52% of the alerts were overridden (i.e error uncorrected by prescribers on the following day. Drug omissions were the most frequently taken into account by prescribers. The classification and regression tree analysis showed that overriding pharmacist's alerts is first related to the ward of the prescriber and then to either Anatomical Therapeutic Chemical class of the drug or the type of error.Since 51% of prescribing errors occurred on the first day of stay, pharmacist should concentrate his analysis of drug prescriptions on this day. The difference of overriding behavior between wards and according drug Anatomical Therapeutic Chemical class or type of error could also guide the validation tasks and programming of electronic alerts.Drug prescribing errors are defined as a prescribing decision or prescription writing process that results in an unintentional, significant reduction in the probability of treatment being timely and effective or increase in the risk of harm, when compared with generally accepted practice. High rates of inpatient prescribing errors have been reported: 1.5-5.3 per 100 drug orders, or 1.4 errors per admission [1,2].In the context of inpatient care, both Computerized Physician Order Entry (CPOE) implemented with Clinical Decision Support Systems [3-7] and the review of drug orders by pharmacists (hereafter referred to as 'pharmacy validati
Viewing Risk Measures as Information
Dominique Gu/'egan,Wayne Tarrant
Quantitative Finance , 2011,
Abstract: Regulation and risk management in banks depend on underlying risk measures. In general this is the only purpose that is seen for risk measures. In this paper we suggest that the reporting of risk measures can be used to determine the loss distribution function for a financial entity. We demonstrate that a lack of sufficient information can lead to ambiguous risk situations. We give examples, showing the need for the reporting of multiple risk measures in order to determine a bank's loss distribution. We conclude by suggesting a regulatory requirement of multiple risk measures being reported by banks, giving specific recommendations.
On the Necessity of Five Risk Measures
Dominique Guégan,Wayne Tarrant
Quantitative Finance , 2011,
Abstract: The banking systems that deal with risk management depend on underlying risk measures. Following the Basel II accord, there are two separate methods by which banks may determine their capital requirement. The Value at Risk measure plays an important role in computing the capital for both approaches. In this paper we analyze the errors produced by using this measure. We discuss other measures, demonstrating their strengths and shortcomings. We give examples, showing the need for the information from multiple risk measures in order to determine a bank's loss distribution. We conclude by suggesting a regulatory requirement of multiple risk measures being reported by banks, giving specific recommendations.
p21Waf1 expression is regulated by nuclear intermediate filament vimentin in neuroblastoma
Xénia Mergui, Marie-Line Puiffe, Dominique Valteau-Couanet, Marc Lipinski, Jean Bénard, Mounira Amor-Guéret
BMC Cancer , 2010, DOI: 10.1186/1471-2407-10-473
Abstract: Vimentin and p21 mRNA levels in NB cell lines as well as in patients' tumors (n = 77) were quantified using Q-PCR. Q-PCR data obtained from tumors of high risk NB patients (n = 40) were analyzed in relation with the overall survival using the Log-rank Kaplan-Meier estimation. siRNA-mediated depletion or overexpression of vimentin in highly or low expressing vimentin cell lines, respectively, followed by protein expression and promoter activation assays were used to assess the role of vimentin in modulating p21 expression.We extend the significant correlation between vimentin and p21 expression to the mRNA level in NB cell lines as well as in patients' tumors. Overall survival analysis from Q-PCR data obtained from tumors of high risk patients suggests that lower levels of p21 expression could be associated with a poorer outcome. Our data additionally indicate that the correlation observed between p21 and vimentin expression levels results from p21 transcriptional activity being regulated by vimentin. Indeed, downregulating vimentin resulted in a significant decrease in p21 mRNA and protein expression as well as in p21 promoter activity. Conversely, overexpressing vimentin triggered an increase in p21 promoter activity in cells with a nuclear expression of vimentin.Our results suggest that p21 mRNA tumor expression level could represent a refined prognostic factor for high risk NB patients. Our data also show that vimentin regulates p21 transcription; this is the first demonstration of a gene regulating function for this type III-intermediate filament.Neuroblastoma (NB), the most common extracranial solid tumor in children, derives from the sympathetic nervous system. It may follow various courses, from spontaneous regression (stage 4S) to aggressive treatment-resistant diseases, which is often metastatic (stage 4) when diagnosed in children aged 12 months or older. This refractory form predominates over all other forms of NB and has a poor prognosis, with an event-f
Early-onset ventilator-associated pneumonia incidence in intensive care units: a surveillance-based study
Philippe Vanhems, Thomas Bénet, Nicolas Voirin, Jean-Marie Januel, Alain Lepape, Bernard Allaouchiche, Laurent Argaud, Dominique Chassard, Claude Guérin, the Study Group
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-236
Abstract: We analyzed data from prospective surveillance between 01/01/2001 and 31/12/2009 in 11 ICUs of Lyon hospitals (France). The inclusion criteria were: first ICU admission, not hospitalized before admission, invasive mechanical ventilation during first ICU day, free of antibiotics at admission, and ICU stay ≥ 48 hours. VAP was defined according to a national protocol. Its incidence was the number of events per 1,000 invasive mechanical ventilation-days. The Poisson regression model was fitted from day 2 (D2) to D8 to incident VAP to estimate the expected VAP incidence from D0 to D1 of ICU stay.Totally, 367 (10.8%) of 3,387 patients in 45,760 patient-days developed VAP within the first 9 days. The predicted cumulative VAP incidence at D0 and D1 was 5.3 (2.6-9.8) and 8.3 (6.1-11.1), respectively. The predicted cumulative VAP incidence was 23.0 (20.8-25.3) at D8. The proportion of missed VAP within 48 hours from admission was 11% (9%-17%).Our study indicates underestimation of early-onset VAP incidence in ICUs, if only VAP occurring ≥ 48 hours are considered to be hospital-acquired. Clinicians should be encouraged to develop a strategy for early detection after ICU admission.The epidemiological surveillance of healthcare-associated infections (HAIs) in intensive care units (ICUs) provides clinicians and caregivers with trend descriptions and contributes to HAI prevention [1-4]. When studies from such epidemiological surveillance programs are carried out, standardized definitions of risk factors for HAI must be used. However, these distinctions as well as the terminology adopted change over time. Indeed, in the last Centers for Disease Control and Prevention definition, HAI replaced the term "hospital-acquired infection" [5].To exclude community-acquired infections, it was acknowledged that a period of 48 hours between ICU admission and the onset of symptoms was required to identify cases as hospital-acquired infections [1-4,6-10]. The time window of 48 hours was first con
Studying the Hurdles of Insulin Prescription (SHIP?): development, scoring and initial validation of a new self-administered questionnaire
Luc Martinez, Silla M Consoli, Louis Monnier, Dominique Simon, Olivier Wong, Bernard Yomtov, Béatrice Guéron, Khadra Benmedjahed, Isabelle Guillemin, Benoit Arnould
Health and Quality of Life Outcomes , 2007, DOI: 10.1186/1477-7525-5-53
Abstract: The 'Studying the Hurdles of Insulin Prescription' (SHIP) questionnaire was developed based on a list of concepts derived from three diabetic patients' focus groups, and was included into two cross-sectional studies with similar design: SHIP Oral study and SHIP Premix study. Diabetic patients treated with oral hypoglycaemic agents (OHA; n = 1,494) and patients already treated with insulin (n = 1,150) completed the questionnaire at baseline, 6- and 12 months. Psychometric properties were assessed: 1) structure analysis by Principal Component Analysis (PCA) with Varimax rotation, 2) internal consistency reliability (Cronbach's alpha), and 3) concurrent validity (Spearman correlation coefficients with the Fear of Self-Injecting (FSI) score of the Diabetes Fear of Injecting and Self-testing Questionnaire. Reluctance/motivation towards insulin was assessed. Scores' ability to predict patients' insulin injection reluctance/motivation and initiation/intensification was evaluated with the Area Under the Receiver Operating Characteristic (ROC) Curve (AUC).PCA analysis confirmed the structure of the 14 items grouped into 3 dimensions: 'acceptance and motivation', 'fear and constraints', and 'restraints and barriers' towards insulin injection. Internal consistency reliability was excellent (Cronbach's alpha > 0.70); concurrent validity was good. The three scores were significantly predictive of patients' reluctance/motivation towards insulin injection initiation, as they were of patients' actual switch, except for the 'restraints and barriers' dimension. 'Acceptance and motivation' and 'fears and constraints' dimensions were also significantly predictive of patients' reluctance/motivation towards insulin intensification. By the end of the 12-month study, 179 of the initially OHA-treated patients had started insulin injections; 186 of the patients already treated with insulin had increased their injections.The SHIP questionnaire provides reliable and valid assessment of diabeti
Treatment for Stable Coronary Artery Disease: A Network Meta-Analysis of Cost-Effectiveness Studies
Thibaut Caruba, Sandrine Katsahian, Catherine Schramm, Ana?s Charles Nelson, Pierre Durieux, Dominique Bégué, Yves Juillière, Olivier Dubourg, Nicolas Danchin, Brigitte Sabatier
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0098371
Abstract: Introduction and Objectives Numerous studies have assessed cost-effectiveness of different treatment modalities for stable angina. Direct comparisons, however, are uncommon. We therefore set out to compare the efficacy and mean cost per patient after 1 and 3 years of follow-up, of the following treatments as assessed in randomized controlled trials (RCT): medical therapy (MT), percutaneous coronary intervention (PCI) without stent (PTCA), with bare-metal stent (BMS), with drug-eluting stent (DES), and elective coronary artery bypass graft (CABG). Methods RCT comparing at least two of the five treatments and reporting clinical and cost data were identified by a systematic search. Clinical end-points were mortality and myocardial infarction (MI). The costs described in the different trials were standardized and expressed in US $ 2008, based on purchasing power parity. A network meta-analysis was used to compare costs. Results Fifteen RCT were selected. Mortality and MI rates were similar in the five treatment groups both for 1-year and 3-year follow-up. Weighted cost per patient however differed markedly for the five treatment modalities, at both one year and three years (P<0.0001). MT was the least expensive treatment modality: US $3069 and 13 864 after one and three years of follow-up, while CABG was the most costly: US $27 003 and 28 670 after one and three years. PCI, whether with plain balloon, BMS or DES came in between, but was closer to the costs of CABG. Conclusions Appreciable savings in health expenditures can be achieved by using MT in the management of patients with stable angina.
Effects of different inputs of organic matter on the response of plant production to a soil water stress in Sahelian region  [PDF]
Abdoulaye Badiane, Ndeye Yacine Badiane Ndour, Fatou Guèye, Saliou Faye, Ibrahima Ndoye, Dominique Masse
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.412125
Abstract: The aim was to study the effects of organic management like the application of organic matters on crop production. This research is placed in the context of climate change impact mitigation. A field experiment was conducted during the dry season. Rainfall inputs were simulated by irrigation to study the effects of water stress during the flowering period of a grain on the agronomic and the physiological behavior of the plant. The measurements were made on the volumetric soil moisture, stomatal conductance, and leaf area index (LAI), grain yield, straw and weight of 100 grains. The water use efficiency (WUE) and yield losses were evaluated. The results of the volumetric soil moisture showed that the use of localized input under water stress (STR-T1) recorded the lowest moisture in the surface horizons. Treatment with localized input under water stress with or without fertilization (STR-T1, STR-T1 + N) showed an ability of stomatal regulation compared to the control (STR- T0) and the input application by spreading (STR- T2). (STR-T1 + N) has initiated an early stomatal closure of the plant because of the effect of nitrogen. However, despite a more pronounced water stress with stomatal closure, the LAI and the grain yield were greater with (STR-T1) and (STR-T1 + N). The results showed that the inputs of localized organic fertilization with or without nitrogen grain yields were the highest regardless of the hydric regime applied. However the losses of grain yield were higher in treatments with organic inputs in spreading and localized under water stress. The WUE by the crop was reduced compared to the control with organic inputs under STR. In this study we show that the use of organic matter increases de farmers risk and this notion of risk is high and it is necessary to consider this risk in the proposals of technical innovations.
An Econometric Study of Vine Copulas
Pierre-André Maugis,Dominique Guégan
International Journal of Economics and Finance , 2010, DOI: 10.5539/ijef.v2n5p2
Abstract: We present a new recursive algorithm to construct vine copulas based on an underlying tree structure. This new structure is interesting to compute multivariate distributions for dependent random variables. We prove the asymptotic normality of the vine copula parameter estimator and show that all vine copula parameter estimators have comparable variance. Both results are crucial to motivate any econometrical work based on vine copulas. We provide an application of vine copulas to estimate the VaR of a portfolio, and show they offer significant improvement as compared to a benchmark estimator based on a GARCH model.
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