15 resultados para Major project
em Université de Lausanne, Switzerland
Resumo:
SummaryResearch projects presented in this thesis aimed to investigate two major aspects of the arenaviruses life cycle in the host cell: viral entry and the biosynthesis of the viral envelope glycoprotein.Old World arenaviruses (OWAV), such as Lassa virus (LASV) and lymphocytic choriomeningitis virus (LCMV), attach to the cell by binding to their receptor, alpha-dystroglycan. Virions are then internalized by a largely unknown pathway of endocytosis and delivered to the late endosome/lysosome where fusion occurs at low pH. In the major project of my thesis, we sought to identify cellular factors involved in OWAV cell entry. Our work indicates that OWAV cell entry requires microtubular transport and a functional multivesicular body (MVB) compartment. Infection indeed depends on phosphatidyl inositol 3-kinase (PI3K) activity and lysobisphosphatidic acid (LBPA), a lipid found in membranes of intraluminal vesicles (ILVs) of the MVB. We further found a requirement of factors that are part of the endosomal sorting complex required for transport (ESCRT), involved in the formation of ILVs. This suggests an ESCRT-mediated sorting of virus- receptor complex during the entry process.During viral replication, biosynthesis of viral glycoprotein takes place in the endoplasmic reticulum (ER) of the host cell. When protein load exceeds the folding capacity of the ER, the accumulation of unfolded proteins is sensed by three ER resident proteins, activating transcription factor 6 (ATF6), inositol-requiring enzyme 1 (IRE1) and PKR-like ER kinase (PERK), whose signaling induces the cellular unfolded protein response (UPR). Our results indicate that acute LCMV infection transiently induces the activation of the ATF6 branch of the UPR, whereas the PERK, and IRE1 axis of UPR are neither triggered nor blocked during infection. Our data also demonstrate that activation of ATF6 pathway is required for optimal viral replication during acute infection.The formation of the mature, fusion-active form of arenaviruses glycoproteins requires proteolytic cleavage mediated by the cellular protease subtilisin kexin isozyme-1 (SKI-l)/site-l protease (SIP). We show that targeting the SKI-1/S1P enzymatic activity with specific inhibitors is a powerful strategy to block arenaviruses productive infection. Moreover, characterization of protease function highlights differences in processing between cellular and viral substrates, opening new possibilities in term of drug development against human pathogenic arenaviruses.RésuméLes projets de recherche présentés dans cette thèse visaient à étudier deux aspects du cycle de vie des arenavirus: l'entrée du virus dans la cellule hôte et la biosynthèse de la glycoprotéine durant la réplication virale.Les arenavirus du vieux monde (OWAV), tels que le virus de Lassa (LASV) et le virus de la chorioméningite lymphocytaire (LCMV) s'attachent à la cellule hôte en se liant à leur récepteur, l'alpha-dystroglycane. Les virions sont ensuite intemalisés par une voie d'endocytose inconnue et livrés à l'endosome tardif/lysosome, où le pH acide permet la fusion entre l'enveloppe virale et la membrane du compartiment. Le projet principal de ma thèse consistait à identifier les facteurs cellulaires impliqués dans l'entrée des OWAV dans la cellule hôte. Nos résultats indiquent que l'entrée des OWAV nécessite le transport microtubulaire et la présence d'un corps multivésiculaire (MVB) fonctionnel. L'infection dépend en effet de l'activité de phosphatidyl inositol 3-kinase (PI3K) et de lysobisphosphatidic acid (LBPA), un lipide présent dans les membranes des vésicules intraluminales (ILVs) du MVB. Nous avons également trouvé l'implication de facteurs constituant l'endosomal sorting complex required for sorting (ESCRT) qui joue un rôle dans la formation des ILVs. Ces donnés suggèrent l'incorporation du complexe virus-récepteur dans des ILVs durant le processus d'entrée.Lors de la réplication virale, la biosynthèse de la glycoprotéine virale a lieu dans le réticulum endoplasmique (ER) de la cellule hôte. Lorsque la charge de protéines nouvellement synthétisées excède la capacité de pliage des protéines dans le ER, l'accumulation de protéines mal pliées est détectée par trois facteurs: activating transcription factor 6 (ATF6), inositol-requiring enzyme 1 (IRE1) et PKR-like ER kinase (PERK). Leur signalisation constitue la réponse cellulaire face aux protéines mal pliées (UPR). Nos résultats montrent que l'infection aiguë avec LCMV induit transitoirement l'activation de la voie de signalisation ATF6 alors que les axes PERK et IRE1 de l'UPR ne sont ni induits ni bloqués pendant l'infection. Nos données prouvent également que l'activation de la voie ATF6 est nécessaire à une réplication virale optimale lors de l'infection aiguë avec LCMV.La maturation des glycoprotéines des arenavirus nécessite un clivage protéolytique par la protéase cellulaire subtilisin kexin isozyme-1 (SKI-l)/site-l protease (SIP). Nous avons démontré que le ciblage de l'activité enzymatique de SKI-1/SIΡ avec des inhibiteurs spécifiques est une stratégie prometteuse pour bloquer l'infection par les arenavirus. La caractérisation du mécanisme d'action de la protéase a, par ailleurs, révélé des différences au niveau du clivage entre les substrats cellulaires et viraux, ce qui ouvre de nouvelles perspectives en terme de développement de médicaments contre les arenavirus pathogènes pour l'homme.
Resumo:
Thirty years after the Canton of Jura entered sovereignty, it has to be admited that the creation of the newly canton did't fullfill the hopes of economic and demografic growth that many could have expected from political independance. Through a plurality of complementary approaches, the research suggest a closer look at, on one hand, the position of the Canton in its territorial context as well as its structure and dynamics and on the other hand, the representations of the territory and its evolution by the social actors. This in order to formulate a set of social demands (of debate, of openness and of overcoming cleavages) which augurs for a new territoriality regime and testify of a requirement of reflexivity toward the state institutions and actions. The analysis allowed to set in evidence the central role of the couple identity-project in the dynamics of change, and to identifiy three main periods in the recent past of the Canton: a period of territorialization, during which grew a strong collective identity, coupled with a major project of society (the creation of the canton of Jura); then followed a period of deterritorialization, with the fragmentation of the collective identity and the lack of a project of society. Then, the third period, with a paradoxical event, the failure in public vote of the the project Jura open Land (Jura Pays ouvert), which was meant to give a second wind to the Canton. We consider this turning point as the start of a new period (of reterritorialization), with an issue linked with the outlines of a renewed "jurassian" identity and the elaboration of a shared territory project.Trente ans après l'entrée en souveraineté, force est de constater que la création du canton du Jura n'a pas permis de répondre aux espérances de développement économique et démographique que l'indépendance politique devait entraîner dans son sillage. Cette recherche se propose, à travers une pluralité d'approches complémentaires, d'examiner d'une part la position du Canton dans son contexte territorial ainsi que sa structure et sa dynamique; d'autre part, les représentations que se font les acteurs du territoire et de son évolution, pour déboucher sur une série de demandes sociales (de débat, d'ouverture et de dépassement des clivages) qui augurent de la transition vers un nouveau régime de territorialité et témoignent d'une exigence de réflexivité envers les institutions et les actions de l'Etat. L'analyse a permis de mettre en évidence le rôle central du couple identité-projet dans la dynamique de changement et d'identifier trois temps forts dans l'évolution récente du Canton, une phase de territorialisation au cours de laquelle s'est constituée une identité forte doublée d'un projet de société majeur, suivie d'une phase de déterritorialisation avec une fragmentation de l'identité collective et l'absence de projet mobilisateur. Enfin, un moment paradoxal, l'échec du projet Jura Pays ouvert, censé redonner un second souffle au Canton, qui amorce une nouvelle étape (de reterritorialisation) avec un questionnement lié aux contours d'une identité jurassienne renouvelée et à l'élaboration d'un projet de territoire partagé.Les ressorts de la production du territoire et de son développement sont analysés à travers le rôle des représentations sociales dans la constitution identitaire et le projet territorial, à l'exemple du canton du Jura. La mise en évidence du rôle central du couple identité-projet dans la dynamique de changement a permis d'identifier trois temps forts dans l'évolution récente du Canton. Une première phase (la création du canton du Jura), au cours de laquelle s'est constituée une identité forte doublée d'un projet de société majeur, suivie d'une phase au cours de laquelle l'identité collective s'est fragmentée en l'absence de projet mobilisateur (la phase de « gestion » de l'Etat). Puis un moment de rupture (l'échec du projet Jura Pays ouvert) et l'amorce d'une transition vers une nouvelle étape, avec un questionnement lié aux contours d'une identité jurassienne renouvelée, à l'élaboration d'un projet de territoire partagé, et à l'action des pouvoirs publics dans un contexte de repositionnement du Canton.
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AbstractIn addition to genetic changes affecting the function of gene products, changes in gene expression have been suggested to underlie many or even most of the phenotypic differences among mammals. However, detailed gene expression comparisons were, until recently, restricted to closely related species, owing to technological limitations. Thus, we took advantage of the latest technologies (RNA-Seq) to generate extensive qualitative and quantitative transcriptome data for a unique collection of somatic and germline tissues from representatives of all major mammalian lineages (placental mammals, marsupials and monotremes) and birds, the evolutionary outgroup.In the first major project of my thesis, we performed global comparative analyses of gene expression levels based on these data. Our analyses provided fundamental insights into the dynamics of transcriptome change during mammalian evolution (e.g., the rate of expression change across species, tissues and chromosomes) and allowed the exploration of the functional relevance and phenotypic implications of transcription changes at a genome-wide scale (e.g., we identified numerous potentially selectively driven expression switches).In a second project of my thesis, which was also based on the unique transcriptome data generated in the context of the first project we focused on the evolution of alternative splicing in mammals. Alternative splicing contributes to transcriptome complexity by generating several transcript isoforms from a single gene, which can, thus, perform various functions. To complete the global comparative analysis of gene expression changes, we explored patterns of alternative splicing evolution. This work uncovered several general and unexpected patterns of alternative splicing evolution (e.g., we found that alternative splicing evolves extremely rapidly) as well as a large number of conserved alternative isoforms that may be crucial for the functioning of mammalian organs.Finally, the third and final project of my PhD consisted in analyzing in detail the unique functional and evolutionary properties of the testis by exploring the extent of its transcriptome complexity. This organ was previously shown to evolve rapidly both at the phenotypic and molecular level, apparently because of the specific pressures that act on this organ and are associated with its reproductive function. Moreover, my analyses of the amniote tissue transcriptome data described above, revealed strikingly widespread transcriptional activity of both functional and nonfunctional genomic elements in the testis compared to the other organs. To elucidate the cellular source and mechanisms underlying this promiscuous transcription in the testis, we generated deep coverage RNA-Seq data for all major testis cell types as well as epigenetic data (DNA and histone methylation) using the mouse as model system. The integration of these complete dataset revealed that meiotic and especially post-meiotic germ cells are the major contributors to the widespread functional and nonfunctional transcriptome complexity of the testis, and that this "promiscuous" spermatogenic transcription is resulting, at least partially, from an overall transcriptionally permissive chromatin state. We hypothesize that this particular open state of the chromatin results from the extensive chromatin remodeling that occurs during spermatogenesis which ultimately leads to the replacement of histones by protamines in the mature spermatozoa. Our results have important functional and evolutionary implications (e.g., regarding new gene birth and testicular gene expression evolution).Generally, these three large-scale projects of my thesis provide complete and massive datasets that constitute valuables resources for further functional and evolutionary analyses of mammalian genomes.
Resumo:
In recent years, analysis of the genomes of many organisms has received increasing international attention. The bulk of the effort to date has centred on the Human Genome Project and analysis of model organisms such as yeast, Drosophila and Caenorhabditis elegans. More recently, the revolution in genome sequencing and gene identification has begun to impact on infectious disease organisms. Initially, much of the effort was concentrated on prokaryotes, but small eukaryotic genomes, including the protozoan parasites Plasmodium, Toxoplasma and trypanosomatids (Leishmania, Trypanosoma brucei and T. cruzi), as well as some multicellular organisms, such as Brugia and Schistosoma, are benefiting from the technological advances of the genome era. These advances promise a radical new approach to the development of novel diagnostic tools, chemotherapeutic targets and vaccines for infectious disease organisms, as well as to the more detailed analysis of cell biology and function.Several networks or consortia linking laboratories around the world have been established to support these parasite genome projects[1] (for more information, see http://www.ebi.ac.uk/ parasites/paratable.html). Five of these networks were supported by an initiative launched in 1994 by the Specific Programme for Research and Tropical Diseases (TDR) of the WHO[2, 3, 4, 5, 6]. The Leishmania Genome Network (LGN) is one of these[3]. Its activities are reported at http://www.ebi.ac.uk/parasites/leish.html, and its current aim is to map and sequence the genome of Leishmania by the year 2002. All the mapping, hybridization and sequence data are also publicly available from LeishDB, an AceDB-based genome database (http://www.ebi.ac.uk/parasites/LGN/leissssoft.html).
Resumo:
OBJECTIVES: This study was designed to assess the prevalence of major cardiovascular risk factors in familial premature coronary artery disease (P-CAD), affecting two or more siblings within one sibship. BACKGROUND: Premature CAD has a genetic component. It remains to be established whether familial P-CAD is due to genes acting independently from major cardiovascular risk factors. METHODS: We recruited 213 P-CAD survivors from 103 sibships diagnosed before age <or=50 (men) or <or=55 (women) years old. Hypertension, hypercholesterolemia, obesity, and smoking were documented at the time of the event in 163 patients (145 men and 18 women). Each patient was compared with two individuals of the same age and gender, diagnosed with sporadic (nonfamilial) P-CAD, and three individuals randomly sampled from the general population. RESULTS: Compared with the general population, patients with sporadic P-CAD had a higher prevalence of hypertension (29% vs. 14%, p < 0.001), hypercholesterolemia (54% vs. 33%, p < 0.001), obesity (20% vs. 13%, p < 0.01), and smoking (76% vs. 39%, p < 0.001). These risk factors were equally or even more prevalent in patients with familial P-CAD (43% [p < 0.05 vs. sporadic P-CAD], 58% [p = 0.07], 21% and 72%, respectively). Overall, only 7 (4%) of 163 of patients with familial P-CAD and 22 (7%) of 326 of patients with sporadic P-CAD had none of these conditions, as compared with 167 (34%) of 489 patients in the general population. CONCLUSIONS: Classic, remediable risk factors are highly prevalent in patients with familial P-CAD. Accordingly, a major contribution of genes acting in the absence of these risk factors is unlikely.
Resumo:
BACKGROUND: Hypertension, hypercholesterolemia, obesity and smoking are highly prevalent among patients with familial premature coronary artery disease (FP-CAD). Whether these risk factors equally affect other family members remains unknown. METHODS: We examined 222 FP-CAD patients, 158 unaffected sibs, 197 offspring and 94 spouses in 108 FP-CAD families (> or = 2 sibs having survived CAD diagnosed before age 51 (M)/56 (F)), and compared them to population controls. RESULTS: Unaffected sibs had a higher prevalence of hypertension (49% versus 24%, p<0.001), hypercholesterolemia (47% versus 34%, p=0.002), abdominal obesity (35% versus 24%, p=0.006) and smoking (39% versus 24%, p=0.001) than population controls. Offspring had a higher prevalence of hypertension (females), hypercholesterolemia and abdominal obesity than population controls. No difference was observed between spouses and controls. Compared to unaffected sibs, FP-CAD affected sibs had a similar risk factor profile, except for smoking, which was more prevalent (76% versus 39%, p=0.008). CONCLUSIONS: Hypertension, obesity and hypercholesterolemia are highly prevalent among first-degree relatives, but not spouses, of patients with FP-CAD. These persons deserve special medical attention due to their familial/genetic susceptibility to atherogenic metabolic abnormalities. In these families, smoking may be the trigger for FP-CAD.
Resumo:
Résumé Objectifs: Cette étude relève la prévalence des principaux facteurs de risque cardiovasculaire dans les coronaropathies précoces (P-CAD) familiales, survenant chez au moins deux frères et/ou soeurs d'une même fratrie. Méthodes: Nous avons recruté 213 survivants atteints de P-CAD, issus de 103 fratries, diagnostiqués avant l'âge de 50 ans chez les hommes et 55 ans chez les femmes. La présence ou non d'hypertension, d'hypercholestérolémie, d'obésité et de tabagisme a été documentée au moment de l'événement chez 163 de ces patients (145 hommes et 18 femmes). Chaque patient a été comparé à deux individus de même âge et sexe, chez qui un diagnostic de P-CAD «sporadique» (non familiale) était posé, et à trois individus choisis au hasard parmi la population générale. Résultats: En comparaison de la population générale, les patients atteints de P-CAD sporadique avaient une prévalence supérieure pour l 'hypertension (29% vs. 14%, p<0.001), le cholestérol (54% vs. 33%, p<0.001), l'obésité (20% vs. 13%, p<0.001) et le tabagisme (76% vs. 39%, p<0.001). Ces facteurs de risque étaient de prévalences similaires, voire supérieures chez les patients atteints de P-CAD familiale (43% [p0.05 vs. P-CAD sporadiques], 58% [p=0.07], 21% et 72% respectivement). Seulement 7 (4%) des 163 patients atteints de P-CAD familiale et 22 (7%) des 326 patients atteints de P-CAD sporadique, ne présentaient aucun facteur de risque cardiovasculaire, comparés à 167 (34%) des 489 patients issus de la population générale. Conclusions: Les facteurs de risque cardiovasculaire classiques et réversibles ont une haute prévalence chez les patients atteints de P-CAD familiale. Ce fait rend improbable une contribution génétique prédominante, agissant en l'absence de facteurs de risque. Summary Objectives: This study was designed to assess the prevalence of major cardiovascular risk factors in familial premature coronary artery disease (P-CAD), affecting two or more siblings within one sibship. Background: Premature CAD has a genetic component. It remains to be established whether familial P-CAD is due to genes acting independently from major cardiovascular risk factors. Methods: We recruited 213 P-CAD survivors from 103 sibships diagnosed before age ?50 (men) or ?55 (women) years old. Hypertension, hypercholesterolemia, obesity, and smoking were documented at the time of the event in 163 patients (145 men and 18 women). Each patient was compared with two individuals of the same age and gender, diagnosed with sporadic (nonfamilial) P-CAD, and three individuals randomly sampled from the general population. Result: Compared with the general population, patients with sporadic P-CAD had a higher prevalence of hypertension (29% vs. 14%, p < 0.001), hypercholesterolemia (54% vs. 33%, p < 0.001), obesity (20% vs. 13%, p < 0.01), and smoking (76% vs. 39%, p < 0.001). These risk factors were equally or even more prevalent in patients with familial P-CAD (43% [p < 0.05 vs. sporadic P-CAD], 58% [p = 0.07], 21% and 72%, respectively). Overall, only 7 (4%) of 163 of patients with familial P-CAD and 22 (7%) of 326 of patients with sporadic P-CAD had none of these conditions, as compared with 167 (34%) of 489 patients in the general population. Conclusions: Classic, remediable risk factors are highly prevalent in patients with familial P-CAD. Accordingly, a major contribution of genes acting in the absence of these risk factors is unlikely.
Resumo:
Rapport de synthèse La prévalence de l'hypertension artérielle, d'une dyslipidémie, d'une obésité et d'un tabagisme est élevée chez les patients qui souffrent d' une maladie coronarienne familiale précoce (MC-FP). L? e but de cette étude fut d'investiguer la prévalence de ces facteurs de risque cardiovasculaires au sein des membres d'une famille dont un patient est affecté d'une MC-FP. Nous avons étudié 108 familles différentes dont au minimum 2 frères/soeurs ont survécu à une maladie coronarienne précoce. Cette dernière fut définie par la survenue d'un événement coronarien avant l'âge de 51 ans pour les hommes et 56 ans pour les femmes. Au total, nous avons identifié 222 patients atteints de MC-FP chez qui 158 frères/soeurs, 197 enfants et 94 époux/épouses ne souffraient pas de maladie coronarienne. Ces parents proches furent comparés à un collectif d'individus "contrôles" issus de la population générale. Les frères/soeurs non affectés avaient une prévalence plus élevée d'hypertension artérielle (49% versus 24%, p<0.001), d'hypercholestérolémie (47% versus 34%, p=0.002), d'obésité abdominale (35% versus 24%, p=0.006) et de tabagisme (39% versus 24%, p=0.001) par rapport aux individus issus de la population générale. Parmi les enfants, une prévalence plus élevée d'hypertension artérielle fut identifiée chez les femmes, et une prévalence plus élevée d'hypercholestérolémie et d'obésité abdominale dans les deux sexes par rapport aux contrôles de la population générale. Aucune différence parmi les facteurs de risque cardiovasculaire n'a été observée entre les époux/ épouses et les contrôles. Les frères/soeurs affectés et non affectés par la MC-FP ont également été comparés entre eux. La prévalence des facteurs de risque était similaire dans les 2 groupes, sauf pour le tabagisme, qui avait une prévalence plus élevée chez les frères/sueurs affectés (76% versus 39%, p=0.008). La prévalence de l'hypertension artérielle, de l'obésité, et de la dyslipidémie est également élevée chez les parents de premier degré de patients atteints de MC-FP, mais pas chez leurs époux/épouses. Ces personnes-là requièrent donc une attention médicale particulière en raison d'une vulnérabilité familiale et/ou génétique augmentée aux anomalies métaboliques athérogènes. Dans ces familles, le tabagisme pourrait être le facteur déclenchant de la MC-FP.
Resumo:
Résumé: Objectifs: Cette étude relève la prévalence des principaux facteurs de risque cardiovasculaire dans les coronaropathies précoces (P-CAD) familiales, survenant chez au moins deux frères et/ou soeurs d'une même fratrie. Méthodes: Nous avons recruté 213 survivants atteints de P-CAD, issus de 103 fratries, diagnostiqués avant l'âge de 50 ans chez les hommes et 55 ans chez les femmes. La présence ou non d'hypertension, d'hypercholestérolémie, d'obésité et de tabagisme a été documentée au moment de l'événement chez 163 de ces patients (145 hommes et 18 femmes). Chaque patient a été comparé à deux individus de même âge et sexe, chez qui un diagnostic de P-CAD «sporadique» (non familiale) était posé, et à trois individus choisis au hasard parmi la population générale. Résultats: En comparaison de la population générale, les patients atteints de P-CAD sporadique avaient une prévalence supérieure pour 1 'hypertension (29% vs. 14%, p<0.001), le cholestérol (54% vs. 33%, p<0.001), l'obésité (20% vs. 13%, p<0.001) et le tabagisme (76% vs. 39%, p<0.001). Ces facteurs de risque étaient de prévalences similaires, voire supérieures chez les patients atteints de P-CAD familiale (43% [p<0.05 vs. P-CAD sporadiques], 58% [p=0.07], 21% et 72%) respectivement). Seulement 7 (4%) des 163 patients atteints de P-CAD familiale et 22 (7%) des 326 patients atteints de P-CAD sporadique, ne présentaient aucun facteur de risque cardiovasculaire, comparés à 167 (34%) des 489 patients issus de la population générale. Conclusions: Les facteurs de risque cardiovasculaire classiques et réversibles ont une haute prévalence chez les patients atteints de P-CAD familiale. Ce fait rend improbable une contribution génétique prédominante, agissant en l'absence de facteurs de risque. Abstract: Objectives: This study was designed to assess the prevalence of major cardiovascular risk factors in familial premature coronary artery disease (P-CAD), affecting two or more siblings within one sibship. Background: Premature CAD has a genetic component. It remains to be established whether familial P-CAD is due to genes acting independently from major cardiovascular risk factors. Methods: We recruited 213 P-CAD survivors from 103 sibships diagnosed before age ?50 (men) or ?55 (women) years old. Hypertension, hypercholesterolemia, obesity, and smoking were documented at the time of the event in 163 patients (145 men and 18 women). Each patient was compared with two individuals of the same age and gender, diagnosed with sporadic (nonfamilial) P-CAD, and three individuals randomly sampled from the general population. Results: Compared with the general population, patients with sporadic P-CAD had a higher prevalence of hypertension (29% vs. 14%, p < 0.001), hypercholesterolemia (54% vs. 33%, p < 0.001), obesity (20% vs. 13%, p < 0.001), and smoking (76% vs. 39%, p < 0.001). These risk factors were equally or even more prevalent in patients with familial P-CAD (43% [p < 0.05 vs. sporadic P-CAD], 58% [p = 0.07], 21% and 72%, respectively). Overall, only 7 (4%) of 163 of patients with familial P-CAD and 22 (7%) of 326 of patients with sporadic P-CAD had none of these conditions, as compared with 167 (34%) of 489 patients in the general population. Conclusions: Classic, remediable risk factors are highly prevalent in patients with familial P-CAD. Accordingly, a major contribution of genes acting in the absence of these risk factors is unlikely
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Elevated plasma cholesterol, high blood pressure and cigarette smoking are three major risk factors for coronary heart disease. Within the framework of Switzerland's participation in the multicenter study MONICA (MONItoring of trends and determinants in CArdiovascular disease), proposed by the WHO, a first risk factor survey was conducted in a representative sample of the population (25-74 years) of two reporting units (cantons of Vaud and Fribourg, canton of Tessin). A high blood cholesterol level (>6,7 mmol/l) is the most common risk factor for coronary heart disease among the studied population. Among men, about 13% have elevated blood pressure, the proportion being about one in ten among women; these proportions increase with age and are slightly above these values in Tessin. Cigarette smoking is still a common behavior; between 25 and 45 years one third of the population (male and female) regularly smoke cigarettes.
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We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.
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BACKGROUND: We present the results of EGASP, a community experiment to assess the state-of-the-art in genome annotation within the ENCODE regions, which span 1% of the human genome sequence. The experiment had two major goals: the assessment of the accuracy of computational methods to predict protein coding genes; and the overall assessment of the completeness of the current human genome annotations as represented in the ENCODE regions. For the computational prediction assessment, eighteen groups contributed gene predictions. We evaluated these submissions against each other based on a 'reference set' of annotations generated as part of the GENCODE project. These annotations were not available to the prediction groups prior to the submission deadline, so that their predictions were blind and an external advisory committee could perform a fair assessment. RESULTS: The best methods had at least one gene transcript correctly predicted for close to 70% of the annotated genes. Nevertheless, the multiple transcript accuracy, taking into account alternative splicing, reached only approximately 40% to 50% accuracy. At the coding nucleotide level, the best programs reached an accuracy of 90% in both sensitivity and specificity. Programs relying on mRNA and protein sequences were the most accurate in reproducing the manually curated annotations. Experimental validation shows that only a very small percentage (3.2%) of the selected 221 computationally predicted exons outside of the existing annotation could be verified. CONCLUSION: This is the first such experiment in human DNA, and we have followed the standards established in a similar experiment, GASP1, in Drosophila melanogaster. We believe the results presented here contribute to the value of ongoing large-scale annotation projects and should guide further experimental methods when being scaled up to the entire human genome sequence.
Resumo:
La présente étude est à la fois une évaluation du processus de la mise en oeuvre et des impacts de la police de proximité dans les cinq plus grandes zones urbaines de Suisse - Bâle, Berne, Genève, Lausanne et Zurich. La police de proximité (community policing) est à la fois une philosophie et une stratégie organisationnelle qui favorise un partenariat renouvelé entre la police et les communautés locales dans le but de résoudre les problèmes relatifs à la sécurité et à l'ordre public. L'évaluation de processus a analysé des données relatives aux réformes internes de la police qui ont été obtenues par l'intermédiaire d'entretiens semi-structurés avec des administrateurs clés des cinq départements de police, ainsi que dans des documents écrits de la police et d'autres sources publiques. L'évaluation des impacts, quant à elle, s'est basée sur des variables contextuelles telles que des statistiques policières et des données de recensement, ainsi que sur des indicateurs d'impacts construit à partir des données du Swiss Crime Survey (SCS) relatives au sentiment d'insécurité, à la perception du désordre public et à la satisfaction de la population à l'égard de la police. Le SCS est un sondage régulier qui a permis d'interroger des habitants des cinq grandes zones urbaines à plusieurs reprises depuis le milieu des années 1980. L'évaluation de processus a abouti à un « Calendrier des activités » visant à créer des données de panel permettant de mesurer les progrès réalisés dans la mise en oeuvre de la police de proximité à l'aide d'une grille d'évaluation à six dimensions à des intervalles de cinq ans entre 1990 et 2010. L'évaluation des impacts, effectuée ex post facto, a utilisé un concept de recherche non-expérimental (observational design) dans le but d'analyser les impacts de différents modèles de police de proximité dans des zones comparables à travers les cinq villes étudiées. Les quartiers urbains, délimités par zone de code postal, ont ainsi été regroupés par l'intermédiaire d'une typologie réalisée à l'aide d'algorithmes d'apprentissage automatique (machine learning). Des algorithmes supervisés et non supervisés ont été utilisés sur les données à haute dimensionnalité relatives à la criminalité, à la structure socio-économique et démographique et au cadre bâti dans le but de regrouper les quartiers urbains les plus similaires dans des clusters. D'abord, les cartes auto-organisatrices (self-organizing maps) ont été utilisées dans le but de réduire la variance intra-cluster des variables contextuelles et de maximiser simultanément la variance inter-cluster des réponses au sondage. Ensuite, l'algorithme des forêts d'arbres décisionnels (random forests) a permis à la fois d'évaluer la pertinence de la typologie de quartier élaborée et de sélectionner les variables contextuelles clés afin de construire un modèle parcimonieux faisant un minimum d'erreurs de classification. Enfin, pour l'analyse des impacts, la méthode des appariements des coefficients de propension (propensity score matching) a été utilisée pour équilibrer les échantillons prétest-posttest en termes d'âge, de sexe et de niveau d'éducation des répondants au sein de chaque type de quartier ainsi identifié dans chacune des villes, avant d'effectuer un test statistique de la différence observée dans les indicateurs d'impacts. De plus, tous les résultats statistiquement significatifs ont été soumis à une analyse de sensibilité (sensitivity analysis) afin d'évaluer leur robustesse face à un biais potentiel dû à des covariables non observées. L'étude relève qu'au cours des quinze dernières années, les cinq services de police ont entamé des réformes majeures de leur organisation ainsi que de leurs stratégies opérationnelles et qu'ils ont noué des partenariats stratégiques afin de mettre en oeuvre la police de proximité. La typologie de quartier développée a abouti à une réduction de la variance intra-cluster des variables contextuelles et permet d'expliquer une partie significative de la variance inter-cluster des indicateurs d'impacts avant la mise en oeuvre du traitement. Ceci semble suggérer que les méthodes de géocomputation aident à équilibrer les covariables observées et donc à réduire les menaces relatives à la validité interne d'un concept de recherche non-expérimental. Enfin, l'analyse des impacts a révélé que le sentiment d'insécurité a diminué de manière significative pendant la période 2000-2005 dans les quartiers se trouvant à l'intérieur et autour des centres-villes de Berne et de Zurich. Ces améliorations sont assez robustes face à des biais dus à des covariables inobservées et covarient dans le temps et l'espace avec la mise en oeuvre de la police de proximité. L'hypothèse alternative envisageant que les diminutions observées dans le sentiment d'insécurité soient, partiellement, un résultat des interventions policières de proximité semble donc être aussi plausible que l'hypothèse nulle considérant l'absence absolue d'effet. Ceci, même si le concept de recherche non-expérimental mis en oeuvre ne peut pas complètement exclure la sélection et la régression à la moyenne comme explications alternatives. The current research project is both a process and impact evaluation of community policing in Switzerland's five major urban areas - Basel, Bern, Geneva, Lausanne, and Zurich. Community policing is both a philosophy and an organizational strategy that promotes a renewed partnership between the police and the community to solve problems of crime and disorder. The process evaluation data on police internal reforms were obtained through semi-structured interviews with key administrators from the five police departments as well as from police internal documents and additional public sources. The impact evaluation uses official crime records and census statistics as contextual variables as well as Swiss Crime Survey (SCS) data on fear of crime, perceptions of disorder, and public attitudes towards the police as outcome measures. The SCS is a standing survey instrument that has polled residents of the five urban areas repeatedly since the mid-1980s. The process evaluation produced a "Calendar of Action" to create panel data to measure community policing implementation progress over six evaluative dimensions in intervals of five years between 1990 and 2010. The impact evaluation, carried out ex post facto, uses an observational design that analyzes the impact of the different community policing models between matched comparison areas across the five cities. Using ZIP code districts as proxies for urban neighborhoods, geospatial data mining algorithms serve to develop a neighborhood typology in order to match the comparison areas. To this end, both unsupervised and supervised algorithms are used to analyze high-dimensional data on crime, the socio-economic and demographic structure, and the built environment in order to classify urban neighborhoods into clusters of similar type. In a first step, self-organizing maps serve as tools to develop a clustering algorithm that reduces the within-cluster variance in the contextual variables and simultaneously maximizes the between-cluster variance in survey responses. The random forests algorithm then serves to assess the appropriateness of the resulting neighborhood typology and to select the key contextual variables in order to build a parsimonious model that makes a minimum of classification errors. Finally, for the impact analysis, propensity score matching methods are used to match the survey respondents of the pretest and posttest samples on age, gender, and their level of education for each neighborhood type identified within each city, before conducting a statistical test of the observed difference in the outcome measures. Moreover, all significant results were subjected to a sensitivity analysis to assess the robustness of these findings in the face of potential bias due to some unobserved covariates. The study finds that over the last fifteen years, all five police departments have undertaken major reforms of their internal organization and operating strategies and forged strategic partnerships in order to implement community policing. The resulting neighborhood typology reduced the within-cluster variance of the contextual variables and accounted for a significant share of the between-cluster variance in the outcome measures prior to treatment, suggesting that geocomputational methods help to balance the observed covariates and hence to reduce threats to the internal validity of an observational design. Finally, the impact analysis revealed that fear of crime dropped significantly over the 2000-2005 period in the neighborhoods in and around the urban centers of Bern and Zurich. These improvements are fairly robust in the face of bias due to some unobserved covariate and covary temporally and spatially with the implementation of community policing. The alternative hypothesis that the observed reductions in fear of crime were at least in part a result of community policing interventions thus appears at least as plausible as the null hypothesis of absolutely no effect, even if the observational design cannot completely rule out selection and regression to the mean as alternative explanations.
Resumo:
Gastric cancer affects about one million people per year worldwide, being the second leading cause of cancer mortality. The study of its etiology remains therefore a global issue as it may allow the identification of major targets, besides eradication of Helicobacter pylori infection, for primary prevention. It has however received little attention, given its comparatively low incidence in most high-income countries. We introduce a consortium of epidemiological investigations named the 'Stomach cancer Pooling (StoP) Project'. Twenty-two studies agreed to participate, for a total of over 9000 cases and 23 000 controls. Twenty studies have already shared the original data set. Of the patients, 40% are from Asia, 43% from Europe, and 17% from North America; 34% are women and 66% men; the median age is 61 years; 56% are from population-based case-control studies, 41% from hospital-based ones, and 3% from nested case-control studies derived from cohort investigations. Biological samples are available from 12 studies. The aim of the StoP Project is to analyze the role of lifestyle and genetic determinants in the etiology of gastric cancer through pooled analyses of individual-level data. The uniquely large data set will allow us to define and quantify the main effects of each risk factor of interest, including a number of infrequent habits, and to adequately address associations in subgroups of the population, as well as interaction within and between environmental and genetic factors. Further, we will carry out separate analyses according to different histotypes and subsites of gastric cancer, to identify potential different risk patterns and etiological characteristics.
Resumo:
Artificial radionuclides ((137)Cs, (90)Sr, Pu, and (241)Am) are present in soils because of Nuclear Weapon Tests and accidents in nuclear facilities. Their distribution in soil depth varies according to soil characteristics, their own chemical properties, and their deposition history. For this project, we studied the atmospheric deposition of (137)Cs, (90)Sr, Pu, (241)Am, (210)Pb, and stable Pb. We compared the distribution of these elements in soil profiles from different soil types from an alpine Valley (Val Piora, Switzerland) with the distribution of selected major and trace elements in the same soils. Our goals were to explain the distribution of the radioisotopes as a function of soil parameters and to identify stable elements with analogous behaviors. We found that Pu and (241)Am are relatively immobile and accumulate in the topsoil. In all soils, (90)Sr is more mobile and shows some accumulations at depth into Fe-Al rich horizons. This behavior is also observed for Cu and Zn, indicating that these elements may be used as chemical analogues for the migration of (90)Sr into the soil.