WorldCat Identities

Roy, Pascal (19..-....; médecin)

Works: 30 works in 33 publications in 2 languages and 61 library holdings
Roles: Thesis advisor, Publishing director, Other, Opponent, Author, Contributor
Classifications: QH323.5, 570.15195
Publication Timeline
Most widely held works by Pascal Roy
Biostatistique by A.-J Valleron( Book )

1 edition published in 2010 in French and held by 14 WorldCat member libraries worldwide

Ce manuel est le fruit de l'expérience pédagogique de trente-sept enseignants du premier cycle des professions de santé. Structuré selon des exigences très strictes en treize chapitres reflétant fidèlement la réalité de l'enseignement médical de première année, il contient tous les éléments nécessaires à une bonne compréhension des méthodes biostatistiques de base par les futurs médecins, pharmaciens, sages-femmes, kinésithérapeutes et autres professionnels de santé. Il s'appuie sur un texte concis, sur plus de 100 illustrations et près de 170 exemples et encadrés pédagogiques, qui proposent en permanence, au fil des pages, un lien direct avec la réalité du futur praticien. Plus de 120 QCM, rédigés dans l'esprit du concours de première année, permettent au lecteur de s'entraîner et d'évaluer sa compréhension du cours. Toutes les réponses à ces questions et des tests interactifs sont disponibles à l'adresse . Un ouvrage absolument indispensable pour réussir son concours. [Ed.]
Modélisation flexible des données de survie en présence de risques concurrents et apports de la méthode du taux en excès by Aurélien Belot( )

2 editions published in 2009 in French and held by 4 WorldCat member libraries worldwide

In epidemiology, the probability of survival (associated to the delay until death) of a cohort of patients is a key indicator of the impact of the disease. But, this survival may be estimated according to various causes of death; these constitute then competing events. In this dissertation, after presenting the analysis setting, we propose a flexible model to estimate jointly the hazards of competing events as well as the effects of prognostic factors in function of the time elapsed since diagnosis. Furthermore, this model allows comparing the effects of the prognostic factors on the competing events; it was applied to an analysis of data on an American cohort of patients with colorectal cancer. However, the causes of death may sometimes be missing or invalid (case of registries that do not routinely collect the causes of death). The statistical method of the excess hazard makes it possible to overcome the need for the causes of death by using the general population mortality to estimate the excess mortality directly or indirectly linked to the disease. An analysis strategy is proposed to estimate the excess mortality as well as the non-linear and/or time-dependent effects of the prognostic factors. In addition to death, the competing events method is also applied to intercurrent events such as relapse or metastasis. A model that combines the competing events and the excess hazard methods is proposed to estimate the hazards of intercurrent events and the excess mortality; it is applied to data from FRANCIM registries on colorectal cancer cases with curative-intent treatment
Etude et modélisation de l'effet conjoint des cancérigènes by Pascal Roy( Book )

2 editions published in 1993 in French and held by 4 WorldCat member libraries worldwide

Modélisation et prédiction : application en cancérologie by Delphine Maucort-Boulch( Book )

2 editions published in 2007 in French and held by 3 WorldCat member libraries worldwide

When dealing with prediction, statistical models have to fit some criteria. The requirements are different for marginal predictions and for individual predictions. Based on two exemples in oncology, particularities and criteria of prognostic models are explored. The first exemple deals with the margianl effect of breast cancer chemoprevention on overall survival for women at high risk. The second exemple deals with individual prediction with a marginal model for Hodgkin's lymphoma patients. Measures of predictive quality are studied, in particular in survival context, especially in Cox proportional hazards model
Comparative optimism in models involving both classical clinical and gene expression information by Caroline Truntzer( )

1 edition published in 2008 in English and held by 2 WorldCat member libraries worldwide

Efficacy of naloxone in reducing postictal central respiratory dysfunction in patients with epilepsy: study protocol for a double-blind, randomized, placebo-controlled trial by On behalf of ENALEPSY study group( )

1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide

Whole exome sequencing in three families segregating a pediatric case of sarcoidosis by In the frame of GSF (Groupe Sarcoïdose France)( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Construction d'un index pronostique : application au lymphome de Hodgkin by Delphine Maucort-Boulch( Book )

1 edition published in 2005 in French and held by 2 WorldCat member libraries worldwide

Familial vs. sporadic sarcoidosis: BTNL2 polymorphisms, clinical presentations, and outcomes in a French cohort by GSF group( )

1 edition published in 2016 in English and held by 2 WorldCat member libraries worldwide

A new prognostic clinicopathological classification of pituitary adenomas: a multicentric case-control study of 410 patients with 8 years post-operative follow-up by The members of HYPOPRONOS( )

1 edition published in 2013 in English and held by 2 WorldCat member libraries worldwide

La catégorisation des variables explicatives continues dans les modèles de prédiction en survie, de l'impact théorique à l'application en recherche by Sophie Bastide( Book )

1 edition published in 2011 in French and held by 2 WorldCat member libraries worldwide

Clinical Characteristics and Outcome of Patients with Lacunar Infarcts and Concurrent Embolic Ischemic Lesions by WAKE-UP investigators( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

Value of Rectal Ultrasound in Predicting Staging and Outcome in Patients With Rectal Adenocarcinoma by Sabine Roman( )

1 edition published in 2004 in English and held by 2 WorldCat member libraries worldwide

Variance component analysis to assess protein quantification in biomarker validation: application to selected reaction monitoring-mass spectrometry by Amna Klich( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Étude des déterminants de la puissance statistique en spectrométrie de masse by Thomas Jouve( )

1 edition published in 2009 in French and held by 1 WorldCat member library worldwide

Mass-spectrometry (MS) belongs to the high-throughput technologies and therefore offers an originalperspective on proteins contained in various biological samples, at a new scale. Biomedicalstudies using this technology are increasingly frequent. They aim at detecting new biomarkersof different biological processes, especially pathological processes leading to cancer. This use asa screening tool asks questions regarding the very detection effectiveness of MS experiments.Statistical power is the direct translation of this effectiveness and reminds us that calibratedstudies are required to offer sufficient guarantees of success. However, this exploration of statisticalpower in mass-spectrometry has not been performed yet. The theme of this work is preciselythe study of power determinants for the detection of biomarkers in MS studies.A literature review was performed, summarizing all necessary pretreatment steps of thesignal analysis, in order to understand the utilized techniques. Available statistical methods forthe analysis of this pretreated signal are also reviewed and put into perspective. Multiple testingsettings arising from MS data suggest a power redefinition. This power redefinition is detailed.Statistical power depends on the study design. Sample sizes, group repartition and the differentialeffect were investigated through MS experiment simulations. Classical results of statisticalpower are acknowledged, with an emphasis on the crucial need to increase sample sizes forbiomarker detection, especially when these markers show low differential effects.Beyond these classical power determinants, mass-spectrometry specific determinants appear.An important power drop is experienced when taking into account the high measurement variabilityencountered in mass-spectrometry. A detrimental synergy exists between measurementvariability and type 1 error control procedures (e.g. FDR). Furtheremore, the imperfections ofpeak detection methods (false and missed peaks) induce a sub-optimal control of this type 1error, leading to another power drop.This work shows three possible intervention levels if we want to improve power in MS studies: a better study design, measurement variability minimisation and pretreatment algorithmsimprovements. Only a work at these three levels can guarantee reliable biomarker detections inthese studies
Construction et validation des modèles de prédiction : étude des utilités by Marion Cortet( )

1 edition published in 2015 in French and held by 1 WorldCat member library worldwide

La médecine est demandeuse de prédictions. Cette question de la prédiction se pose à différents moments de la prise en charge du patient, au moment du diagnostic, au moment de l'évaluation du pronostic et au moment du suivi, pour prendre les meilleures décisions possibles en termes de choix d'examens complémentaires et de choix de thérapeutique. La prédiction permet d'apporter une information au médecin et au patient pour prendre la décision. Pour construire ces modèles de prédiction, on dispose de bases de données qui nous permettent d'évaluer l'association entre des données cliniques ou biologiques et la probabilité de survenue d'un évènement. Pour quantifier ces associations, on utilise des modèles de régression logistique qui sont estimés d'après la méthode du maximum de vraisemblance. Pour évaluer ces modèles, on dispose de différents critères, qui quantifient leur adéquation, leur capacité de discrimination, leur calibration. Ces modèles vont nous permettre de prendre une décision. Les erreurs de prédiction vont mener à des erreurs de décision. Les conséquences de ces décisions sont quantifiables grâce à la théorie des utilités. C'est donc un critère quantifiant l'utilité du modèle qui nous permet de choisir le modèle le plus utile. La construction de modèles de prédiction est particulièrement importante dans le domaine clinique de l'obstétrique. En effet, il est important dans le cas des hémorragies de la délivrance de prévenir l'aggravation de la situation, et donc de distinguer les patientes qui vont s'aggraver très rapidement. Le taux de fibrinogène a été étudié, comme prédicteur d'une évolution grave de l'hémorragie. Les variables cliniques disponibles au moment du diagnostic ont ensuite été étudiées. Dans la situation de la rupture prématurée des membranes, il existe un choix à faire entre deux décisions qui induisent une morbidité néonatale et maternelle : la naissance prématurée et le risque de chorioamniotite. Des marqueurs du risque de chorioamniotite pourraient donc faciliter la prise de décision en augmentant l'information pour le clinicien. De plus en plus de modèles de prédiction sont développés dans toutes les situations cliniques. Il faut rester critique vis-à-vis de ces modèles. Leur évaluation doit tenir compte de leur utilisation, et doit donc tenir compte de leur utilité en situation de prise de décision
Approches intégrées du génome et du transcriptome dans les maladies complexes humaines by Maxime Rotival( )

1 edition published in 2011 in French and held by 1 WorldCat member library worldwide

This thesis deals with the study of the relation between genotype and expression and its influence on the development of complex diseases. This work brings both methodological and applied results.First, we study the relation between genotype and transcriptome by establishing a database of eQTL (expression quantitative Trait Loci) in monocytes and we evaluate the contribution of eQTL for the interpretation of results from Genome Wide Association Studies (GWAS).We then provide a methodology for the identi_cation of genetic polymorphisms regulating modules of co-expressed genes that we apply to a large scale populationnal study of the monocyte transcriptome.We thus identify several loci associated with modules of co-regulated genes, several of which are involved in the susceptibility to type I diabetes. We also show that the isolation of monocytes can induce complex bias through contamination from unwanted cell types and we provide a method to control for such bias in the analysis
Apport des méthodes d'inférence causale et de la modélisation additive de survie pour l'évaluation d'un effet thérapeutique dans le domaine spécifique de la cardiologie et de la chirurgie cardiaque by Nicolas Girerd( )

1 edition published in 2014 in French and held by 1 WorldCat member library worldwide

Devant les difficultés d'inclusion et de réalisation des essais cliniques en chirurgie cardiaque, rares sont les données randomisées disponibles dans ce domaine. On doit donc, autant que possible, se satisfaire de données observationnelles. Cependant, les procédures chirurgicales sont des traitements qui s'adaptent aux caractéristiques du patient, ce qui engendre un biais d'attribution important. Nous avons étudié l'impact du type de revascularisation chirurgicale (complète ou incomplète) sur la survie à long terme grâce à un appariement 4/1 sur le score de propension. Nous avons identifié, une fois le score de propension correctement pris en compte, une interaction significative sur une échelle relative entre le type de revascularisation chirurgicale et l'âge vis-à-vis de la survie toute cause à long terme, l'effet étant moins marqué chez les patients les plus âgés. Nous avons ensuite étudié l'interaction entre âge et effet du traitement sur une échelle additive et une échelle relative, en utilisant des modèles de survie additif ou multiplicatif sur le taux. Nous avons identifié une interaction sous-multiplicative significative alors qu'il n'existait pas d'interaction notable dans le modèle de survie additif, suggérant que l'effet du traitement était plutôt additif dans ce contexte. Par ailleurs, nous avons mesuré la différence de risque à partir du modèle de survie multiplicatif chez des patients de différentes classes d'âge. La différence de risque extraite du modèle multiplicatif était similaire dans les différents groupes d'âge confirmant un effet absolu constant dans les différentes classes d'âge malgré un effet relatif plus faible chez les sujets âgés. Notre travail incite à une évaluation de l'effet de traitement dans des jeux de données observationnelles sur une échelle relative et sur une échelle absolue après une prise en compte du score de propension
Centralization errors in comparative genomic hybridization array analysis of pituitary tumor samples( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

Abstract: Reliable interpretation of comparative genomic hybridization array (aCGH) results requires centralization and normalization of the data. We evaluated the reliability of aCGH centralization by comparing aCGH results (with classical centralization-normalization steps) to fluorescence in situ hybridization (FISH) results. In addition, we propose a method to correct centralization bias. Sixty-six pituitary tumors were analyzed (Agilent aCGH + SNP 4 × 180K microarray). For each tumor, the FISH-based log2 (ratios) of a subset of chromosomes were compared with the corresponding aCGH raw log2 (ratios). With our new normalization-centralization process, this difference was added to all log2 (ratios), before performing loess regression on non-altered probes only. Finally, the mean log2 (ratio) and the percentage of normal probes were compared between CGHnormaliter and our new FISH-based method. For 11 tumors, FISH results and raw CGH log2 (ratios) differed significantly. In addition, nine tumors showed discrepancies between results generated by CGHnormaliter and our new-method. Such discrepancies seemed to occur with tumours with many abnormalities (0%-40% normal probes), rather than in those tumours with fewer abnormalities (31%-100% normal probes). Five tumors had too few normal probes to allow normalization. In these tumors, which can exhibit many changes in DNA copy number, we found that centralization bias was frequent and uncorrected by current normalization methods. Therefore, an external control for centralization, such as FISH analysis, is required to insure reliable interpretation of aCGH data
Test des effets centre en épidémiologie clinique by Lucie Biard( )

1 edition published in 2016 in French and held by 1 WorldCat member library worldwide

Centre effects modelling within the framework of survival data often relies on the estimation of Cox mixed effects models. Testing for a centre effect consists in testing to zero the variance component of the corresponding random effect. In this framework, the identification of the null distribution of usual tests statistics is not always straightforward. Permutation procedures have been proposed as an alternative, for generalised linear mixed models.The objective was to develop a permutation test procedure for random effects in a Cox mixed effects model, for the test of centre effects.We first developed and evaluated permutation procedures for the test of a single centre effect on the baseline risk. The test was used to investigate a centre effect in a clinical trial of induction chemotherapy for patients with acute myeloid leukaemia.The second part consisted in extending the procedure for the test of multiple random effects, in survival models. The aim was to be able to examine both center effects on the baseline risk and centre effects on the effect of covariates. The procedure was illustrated on two cohorts of acute leukaemia patients. In a third part, the permutation approach was applied to a cohort of critically ill patients with hematologic malignancies, to investigate centre effects on the hospital mortality.The proposed permutation procedures appear to be robust approaches, easily implemented for the test of random centre effect in routine practice. They are an appropriate tool for the analysis of centre effects in clinical epidemiology, with the purpose of understanding their sources
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P. Roy wetenschapper

Pascal Roy forsker

Pascal Roy researcher

French (14)

English (9)