Effets d'une modification de l'environnement post-natal dans un modèle de programmation foetale des pathologies adultes

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

La complémentarité entre les normes de prévention et de protection en santé publique : regard sur l'éclosion de légionellose à Québec en 2012

Résumé : Quatre fonctions essentielles de santé publique ressortent de la Loi sur la santé publique, dont la prévention ainsi que la protection. Ces deux fonctions sont complémentaires en ce sens que des lacunes dans la mise en oeuvre de l’une peuvent miner la réalisation de l’autre et ainsi entraîner des conséquences sanitaires regrettables. C’est donc à la lumière de cette nécessaire complémentarité entre les fonctions de prévention et de protection, observée à travers les normes juridiques assurant leur exercice respectif, qu’un regard est porté dans le cadre de cet essai sur l’éclosion de légionellose survenue à Québec à l’été 2012. Il s’agit plus précisément de déterminer si cette éclosion a traduit un manque de complémentarité entre les normes de prévention et de protection alors en vigueur et, le cas échéant, de tenter d’en tirer des leçons pour l’avenir. // Abstract : Public health is based on four essential functions including prevention and protection. These two functions are complementary since any gap in the implementation of one function can undermine the realization of the other one and could result in negative sanitary consequences. In the light of this necessary complementarity between the functions of prevention and protection that can be observed through legal standards in place, this essay suggests an analysis of the legionellosis epidemic that occurred in Quebec City in summer 2012. The specific question is to determine if this epidemic revealed a lack of complementarity between prevention and protection standards that were in force at that time and if so, to acknowledge and learn from these events

Hypoxie placentaire et atteinte surrénalienne foetale dans un modèle de restriction de croissance intra-utérine chez le rat

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

La complémentarité entre les normes de prévention et de protection en santé publique : regard sur l'éclosion de légionellose à Québec en 2012

Résumé : Quatre fonctions essentielles de santé publique ressortent de la Loi sur la santé publique, dont la prévention ainsi que la protection. Ces deux fonctions sont complémentaires en ce sens que des lacunes dans la mise en oeuvre de l’une peuvent miner la réalisation de l’autre et ainsi entraîner des conséquences sanitaires regrettables. C’est donc à la lumière de cette nécessaire complémentarité entre les fonctions de prévention et de protection, observée à travers les normes juridiques assurant leur exercice respectif, qu’un regard est porté dans le cadre de cet essai sur l’éclosion de légionellose survenue à Québec à l’été 2012. Il s’agit plus précisément de déterminer si cette éclosion a traduit un manque de complémentarité entre les normes de prévention et de protection alors en vigueur et, le cas échéant, de tenter d’en tirer des leçons pour l’avenir. // Abstract : Public health is based on four essential functions including prevention and protection. These two functions are complementary since any gap in the implementation of one function can undermine the realization of the other one and could result in negative sanitary consequences. In the light of this necessary complementarity between the functions of prevention and protection that can be observed through legal standards in place, this essay suggests an analysis of the legionellosis epidemic that occurred in Quebec City in summer 2012. The specific question is to determine if this epidemic revealed a lack of complementarity between prevention and protection standards that were in force at that time and if so, to acknowledge and learn from these events

The fossil record as an archive of biological information in marine ice-scoured environments : Canadian Arctic Ocean

Post-mortem alteration of bivalve shells on arctic ice-scoured shelves helps illucidate the fidelity of death and fossil assemblages in these settings. Degradation rates and processes were constrained by (1) characterizing the taphonomic signature of death assemblages, (2) evaluating the live-dead fidelity of the benthos, and (3) net changes in experimentally deployed shells. Results revealed an extremely harsh taphonomic mill controlled by bioerosion, fragmentation and dissolution. Only select species accumulated in death assemblages, resulting in low taxonomic fidelity; at the habitat level 50% of the live species are found dead. 100% of the dead species are found alive, suggesting no temporal or spatial exotic contributions.Selectively preserved species could be time-averaged over 1 000s of years based on a preliminary model, yet high damage profiles suggest shorter scales of time-averaging. Skeletons are highly degraded compared to assemblages from temperate or tropical seas and reflect only a portion the living skeletonized community

Placental Underperfusion in a Rat Model of Intrauterine Growth Restriction Induced by a Reduced Plasma Volume Expansion.

Lower maternal plasma volume expansion was found in idiopathic intrauterine growth restriction (IUGR) but the link remains to be elucidated. An animal model of IUGR was developed by giving a low-sodium diet to rats over the last week of gestation. This treatment prevents full expansion of maternal circulating volume and the increase in uterine artery diameter, leading to reduced placental weight compared to normal gestation. We aimed to verify whether this is associated with reduced remodeling of uteroplacental circulation and placental hypoxia. Dams were divided into two groups: IUGR group and normal-fed controls. Blood velocity waveforms in the main uterine artery were obtained by Doppler sonography on days 14, 18 and 21 of pregnancy. On day 22 (term = 23 days), rats were sacrificed and placentas and uterine radial arteries were collected. Diameter and myogenic response of uterine arteries supplying placentas were determined while expression of hypoxia-modulated genes (HIF-1α, VEGFA and VEGFR2), apoptotic enzyme (Caspase -3 and -9) and glycogen cells clusters were measured in control and IUGR term-placentas. In the IUGR group, impaired blood velocity in the main uterine artery along with increased resistance index was observed without alteration in umbilical artery blood velocity. Radial uterine artery diameter was reduced while myogenic response was increased. IUGR placentas displayed increased expression of hypoxia markers without change in the caspases and increased glycogen cells in the junctional zone. The present data suggest that reduced placental and fetal growth in our IUGR model may be mediated, in part, through reduced maternal uteroplacental blood flow and increased placental hypoxia

Visceral / epicardial adiposity in nonobese and apparently healthy young adults : association with the cardiometabolic profile

Objective: We investigate associations of regional adipose tissues with cardiometabolic profile of nonobese and apparently healthy young adults. Methods: Four hundred twenty-five nonobese and apparently healthy individuals were assessed for blood pressure and fasting lipid profile, blood glucose and adiponectin. Subcutaneous abdominal adipose tissue (SAT) and ectopic fat depots (visceral abdominal adipose tissue [VAT], epicardial adipose tissue [EAT] and hepatic fat fraction [HFF]) were quantified by magnetic resonance imaging. Results: According to anthropometric measurements, blood pressure and blood markers, the population (18–35 years, 54% women) had a low cardiometabolic risk. Compared to women, men had more VAT, EAT and HFF, but less SAT. Regional adipose tissues were positively correlated with each other. VAT and EAT carried significant correlations with all markers of cardiometabolic risk, while SAT and HFF correlated variably with these markers. While taking into account age and gender, SAT, VAT and EAT were associated with most cardiometabolic markers, while HFF was only associated with total cholesterol/high-density lipoprotein ratio (TC/HDL-C) and triglycerides (TG). When comparing SAT, VAT and EAT head-to-head, VAT was the only adipose tissue location maintaining significant association with most markers of cardiometabolic risk. Greater VAT (=50th percentile) was associated with a worse cardiometabolic profile, whether individuals were overweight or normal weight. Conclusion: Even in nonobese and apparently healthy young women and men, accumulation of ectopic visceral adiposity in general, and of VAT in particular, is associated with a worse cardiometabolic profile whether individuals were overweight or normal weight

Cardiac morphology and function reference values derived from a large subset of healthy young Caucasian adults by magnetic resonance imaging

Aims: Assessment of cardiac anatomy and function by cardiovascular magnetic resonance (CMR) is accurate and reproducible and is commonly performed to clarify borderline results obtained by other techniques. Normal reference values are lacking in a large sample of young healthy adults. As CMR is increasingly solicited to discriminate normality from equivocal disease in this population, we sought to determine reliable reference values. Methods and results: A sample of 434 Caucasian adults aged 26 ± 4 years (45% male) without cardiovascular disease or risk factors (including obesity and smoking) underwent CMR. Blood pressure, electrocardiogram, and plasma markers (lipid profile, fasting glucose, troponin, and Nt-pro-BNP) were within normal limits and typical of a low-cardiometabolic-risk profile. End-diastolic (ED), end-systolic (ES), and stroke volumes were greater in men for left and right atria and ventricles. Left ventricular (LV) mass was higher in men. ED wall thickness of all segments was greater in men, whereas ES wall thickening (segmental function) was similar in both genders. After normalization to body surface area, all gender differences remained. Left and right ventricular volumes were lower, and left atrial volumes were higher in older individuals. In contrast, LV mass was not associated with age. Conclusion: This is the first large database of reference ranges for ventricular and atrial functions, volumes, and mass in young Caucasian men and women devoid of cardiovascular disease and risk factors. These data will contribute to improving the accuracy of CMR interpretation for clinical and research applications