120 research outputs found
Regulation of Interleukin-1 governs acute intrauterine inflammation to improve gestational and neonatal outcome
La naissance prĂ©maturĂ©e (NP; naissance avant 37 semaines de gestation) est la cause principale de mortalitĂ© et de morbiditĂ© nĂ©onatale Ă travers le monde, et les nourrissons survivants sont Ă risque de dĂ©ficits fonctionnels Ă long-terme. La physiopathologie du travail prĂ©terme spontanĂ© est largement attribuable aux processus inflammatoires intra-utĂ©rins indĂ©pendamment de lâĂ©tiologie, de lâĂąge gestationnel Ă lâaccouchement, et de la prĂ©sence dâinfection. De façon importante, lâinflammation intra-utĂ©rine se propage au fĆtus, aprĂšs quoi le dĂ©clencheur initial est amplifiĂ© pour causer des dommages aux organes fĆtaux, compromettant ainsi lâissue nĂ©onatal. De tous les mĂ©diateurs pro-inflammatoires, lâinterleukine-1 (IL-1) se dĂ©marque comme Ă©tant un joueur majeur dans la NP et lâinflammation fĆtale. Ainsi, de moduler son action durant la gestation pourrait ĂȘtre essentiel afin dâatteindre une meilleure issue nĂ©onatale. Dans la prĂ©sente, nous dĂ©montrons que la rĂ©gulation antĂ©natale de lâIL-1 par le lactate (ou lâacide 3,5-dihydroxybenzoĂŻque [3,5-DHBA]) via le rĂ©cepteur myomĂ©trial anti-inflammatoire GPR81, ainsi quâun heptapeptide antagoniste non-compĂ©titif du rĂ©cepteur de lâIL-1 dĂ©veloppĂ© dans notre laboratoire et nommĂ© 101.10, prĂ©viennent la NP et amĂ©liorent la survie nĂ©onatale dans des modĂšles murins de NP induite par lâinflammation intra-utĂ©rine ou lâinfection systĂ©mique. SpĂ©cifiquement, nous montrons que lâadministration maternelle antĂ©natale de 101.10 prĂ©vient le dĂ©clenchement prĂ©maturĂ© de lâinflammation utĂ©rine, choriodĂ©ciduale, placentaire, amniotique et fĆtale, diminuant ainsi les dommages aux organes fĆtaux et les dĂ©ficits fonctionnels chez la progĂ©niture. Dans ce contexte, 101.10 a dĂ©montrĂ© une efficacitĂ© supĂ©rieure Ă anakinra (Kineret), un antagoniste compĂ©titif du rĂ©cepteur de lâIL-1, surtout pour prĂ©venir la NP et la mortalitĂ© nĂ©onatale. De plus, nous dĂ©montrons que le 101.10 agit par sĂ©lectivitĂ© fonctionnelle en inhibant les signaux de transduction activĂ©s par lâIL-1, spĂ©cifiquement p38, c-Jun N-terminal kinase (JNK), c-jun, et Rho GTPase/ Rho-associated coiled-coil-containing protein kinase (ROCK), tout en prĂ©servant dĂ©sirablement lâactivation de IÎșBα et de nuclear factor-kappa B (NF-ÎșB) induite par lâIL-1. Dans un second ensemble dâexpĂ©riences, nous dĂ©couvrons un mĂ©canisme inĂ©dit de rĂ©troaction nĂ©gative intra-utĂ©rine par lequel le mĂ©tabolisme anaĂ©robique sollicitĂ© durant la phase de travail utĂ©rin actif produit des niveaux Ă©levĂ©s de lactate, ce qui en retour active GPR81 dans le myomĂštre pour diminuer la cascade inflammatoire aigĂŒe induite par IL-1. De façon correspondante, les souris GPR81-/- prĂ©sentent plus dâinflammation utĂ©rine durant le travail et des taux plus Ă©levĂ©s de dystocie utĂ©rine, alors quâĂ lâinverse lâadministration de lâagoniste de GPR81 3,5-DHBA diminue la rĂ©ponse inflammatoire utĂ©rine Ă lâIL-1 et prĂ©vient la NP induite par le lipopolysaccharide (LPS, une endotoxine provenant des bactĂ©ries gram(-)). En somme, nos donnĂ©es dĂ©montrent un rĂŽle majeur de lâIL-1 antĂ©natale Ă Ă©liciter la NP et les dommages Ă long-terme aux organes fĆtaux, en plus de dĂ©crire une approche thĂ©rapeutique inĂ©dite pour inhiber le rĂ©cepteur de lâIL-1 avant la naissance tout en prĂ©servant les voies de signalisation inflammatoires physiologiquement importantes.Preterm birth (PTB; birth before 37 weeks' gestation) is the leading cause of neonatal mortality and morbidity worldwide, and surviving infants are at risk of long-lasting functional impairments. The pathophysiology of spontaneous preterm labor has been largely attributed to intrauterine inflammatory processes independent of aetiology, gestation age at delivery, and presence of infection. Importantly, intrauterine inflammation can propagate to the fetus whereupon the initial trigger is amplified to cause fetal organ injury, thereby compromising neonatal outcome. Of all pro-inflammatory mediators, interleukin-1 (IL-1) stands out as a major player in PTB and fetal inflammation. Therefore, modulating its action antenatally may be key to achieve better gestational and neonatal outcomes. Herein, we show that antenatal regulation of IL-1 by lactate (or 3,5-dihydroxybenzoic acid [3,5-DHBA]) via activation of anti-inflammatory GPR81 in myometrium, or by an heptapeptide noncompetitive antagonist of IL-1 receptor developed in our laboratory and termed 101.10, prevents PTB and improves neonatal survival in intrauterine-inflammatory and systemic-infectious murine models of PTB. Specifically, we show that antenatal maternal administration of 101.10 prevents premature triggering of uterine, choriodecidual, placental, amniotic, and fetal inflammation, thereby decreasing organ injury and functional impairment in progeny. In this setting, 101.10 has shown superior efficacy as compared to anakinra (Kineret), a competitive IL-1 receptor antagonist, especially to prevent PTB and neonatal mortality. Further, we demonstrate that 101.10 exhibits functional selectivity by inhibiting IL-1-induced signals transducers p38, c-Jun N-terminal kinase (JNK), c-jun, and Rho GTPase/ Rho-associated coiled-coil-containing protein kinase (ROCK), while desirably preserving IL-1-induced activation of IÎșBα and nuclear factor-kappa B (NF-ÎșB). In a second set of experiments, we uncover a novel uterine negative feedback mechanism whereby the anaerobic metabolism solicitated during active labor produces large levels of lactate, which in turn activates GPR81 in myometrium to decrease IL-1-induced acute inflammatory cascade. Correspondingly, GPR81-/- mice display increased uterine inflammation during labor and increased rates of labor dystocia, whereas inversely administration of the GPR81 agonist 3,5-DHBA decreases the uterine inflammatory response to IL-1 and prevents lipopolysaccharide (LPS, gram(-) bacteria endotoxin)-induced PTB. Altogether, this data points to a major role of antenatal IL-1 in eliciting PTB and long-lasting fetal organ injury, and describes a novel therapeutic approach to inhibit IL-1 receptor antenatally while preserving important physiological inflammatory signaling pathways
Participation de l'endocarde dans les malformations cardiaques du syndrome Holt-Oram
Mémoire numérisé par la Direction des bibliothÚques de l'Université de Montréal
Induction rapide, contrÎlée par capteur de température virtuel, d'une hypothermie en ventilation liquidienne totale
L'hypothermie thĂ©rapeutique modĂ©rĂ©e (HTM) consiste Ă abaisser la tempĂ©rature corporelle d'un patient entre 32 et 34 °C. Cette mĂ©thode a prouvĂ© ses vertus thĂ©rapeutiques pour la neuroprotection et la cardioprotection lors d'insultes hypoxiques ou ischĂ©miques en empĂȘchant les cellules touchĂ©es d'entrer en apoptose. La ventilation liquidienne totale (VLT) consiste Ă assurer les Ă©changes gazeux dans les poumons Ă l'aide d'un liquide, typiquement des perfluorocarbones (PFC). Un ventilateur liquidien se charge ventiler le patient par un renouvellement cyclique de PFC oxygĂ©nĂ© et Ă tempĂ©rature contrĂŽlĂ©e. La VLT, utilisant les PFC comme fluides caloporteurs et le poumon comme Ă©changeur thermique, permet une induction d'HTM ultra rapide. Cependant, il n'existe encore aucun ventilateur liquidien avec une fonction automatisĂ©e d'induction rapide d'HTM par VLT. L'Ă©quipe Inolivent de l'UniversitĂ© de Sherbrooke possĂšde la technologie de respirateur liquidien la plus Ă©voluĂ©e au monde. Le but du prĂ©sent projet est d'Ă©quiper le respirateur INOLIVENT-5.0 d'une fonction automatisĂ©e d'induction d'HTM et d'un contrĂŽle de la tempĂ©rature corporelle. Un capteur virtuel de la tempĂ©rature du patient en fonction de la tempĂ©rature du PFC expirĂ© a Ă©tĂ© dĂ©veloppĂ©. Un systĂšme d'Ă©changeur de chaleur bidirectionnel permettant de refroidir et de chauffer le PFC a Ă©tĂ© conçu et implantĂ©. Le systĂšme d'Ă©changeur de chaleur et le circuit de PFC ont Ă©tĂ© modĂ©lisĂ©s mathĂ©matiquement. Deux modĂšles par compartiments du poumon comme Ă©changeur thermique en VLT sur des agneaux nouveau-nĂ©s et des lapins adultes ont pu ĂȘtre dĂ©veloppĂ©s Ă l'aide de la littĂ©rature et d'expĂ©rimentations animales. A la suite de la validation in vivo du capteur virtuel de tempĂ©rature et des modĂšles mathĂ©matiques, les contrĂŽleurs de tempĂ©ratures corporelles ont Ă©tĂ© conçus. Les contrĂŽles pour l'induction rapide d'HTM par VLT ont Ă©tĂ© mis en place pour atteindre rapidement l'HTM, tout en assurant que la tempĂ©rature du coeur ne descende pas sous 30°C, prĂ©venant ainsi les arythmies cardiaques. Des contrĂŽles diffĂ©rents ont dĂ» ĂȘtre mis en place dĂ©pendamment si l'HTM est induite au dĂ©part de la VLT ou lors d'une VLT normotherme. De plus, un rĂ©gulateur de la tempĂ©rature corporelle a Ă©tĂ© conçu pour permettre des rĂ©chauffements progressifs Ă taux prescrits par l'utilisateur. Finalement, le capteur virtuel et les diffĂ©rents contrĂŽleurs ont Ă©tĂ© validĂ©s sur 7 agneaux nouveau-nĂ©s Ă l'animalerie du Centre Hospitalier Universitaire de Sherbrooke (Canada) et sur 7 lapins adultes dans les laboratoires de l'Ăcole Nationale VĂ©tĂ©rinaire d'Alfort (France). Le capteur virtuel et les contrĂŽleurs fonctionnent correctement sur le modĂšle ovin et rĂ©pondent aux spĂ©cifications fixĂ©es. Dans le cas du modĂšle lapin, les frĂ©quences respiratoires et les volumes courants Ă©tant plus faibles que sur l'agneau, un biais apparaĂźt au capteur virtuel et l'HTM est plus longue Ă atteindre, mais plusieurs pistes d'amĂ©lioration sont proposĂ©es
Linking high school students' achievement goal orientations with their competence beliefs and their perception of teachers' emotional support during the COVID-19 pandemic
Abstract : Due to the COVID-19 pandemic, adolescents have experienced limitations in their
everyday activities. Consequently, their mental health has become an area of concern.
However, there has been much less of a focus on the factors and mechanisms
contributing to how they have approached their various academic activities during
the pandemic. The current study fills this gap by investigating associations between
adolescentsâ competence beliefs and perception of teachersâ emotional support and
their achievement goals (mastery, performance, and work avoidance) at the onset of
the second wave of this pandemic in Canada. Participants were 90 Canadian high
school adolescents in grades 9 and 10 and they were surveyed in November of 2020.
Data were analyzed using multiple regression and mediation analyses. Among the most
salient results, competence beliefs were found to predict achievement goals, above and
beyond teachersâ emotional support, and these beliefs were significantly and positively
associated with mastery and performance orientation, and marginally and negatively
associated with work avoidance orientation. Results also showed that competence
beliefs mediated the association between teachersâ emotional support and the mastery
goal orientation. These findings are discussed in light of relevant pre-pandemic evidence
about the role of competence beliefs and teachersâ emotional support on achievement
goal orientations
How do predators generalize warning signals in simple and complex prey communities? Insights from a videogame
The persistence of distinct warning signals within and between sympatric mimetic communities is a puzzling evolutionary question because selection favours convergence of colour patterns among toxic species. Such convergence is partly shaped by predators' reaction to similar but not identical stimulus (i.e. generalization behaviour), and generalization by predators is likely to be shaped by the diversity of local prey. However, studying generalization behaviour is generally limited to simple variations of prey colour patterns. Here, we used a computer game played by humans as surrogate predators to investigate generalization behaviours in simple (4 morphs) and complex (10 morphs) communities of unprofitable (associated with a penalty) and profitable butterflies. Colour patterns used in the game are observed in the natural populations of unprofitable butterfly species such as Heliconius numata. Analyses of 449 game participants' behaviours show that players avoided unprofitable prey more readily in simple than in complex communities. However, generalization was observed only in players that faced complex communities, enhancing the protection of profitable prey that looked similar to at least one unprofitable morph. Additionally, similarity among unprofitable prey also reduced attack rates only in complex communities. These results are consistent with previous studies using avian predators but artificial colour patterns and suggest that mimicry is more likely to evolve in complex communities where increases in similarity are more likely to be advantageous
Adipose tissue attenuation and adipocyte size
Objective: To assess the ability of CT-derived measurements including adipose tissue attenuation and area to predict fat cell hypertrophy and related cardiometabolic risk. Methods: Abdominal adipose tissue areas and radiologic attenuation were assessed using 4 CT images in 241 women (age: 47 years, BMI: 26.5 kg/m2). Fat cell weight was measured in paired VAT and SAT samples. Fasting plasma lipids, glucose and insulin levels were measured. Results: Adipose tissue attenuation was negatively correlated with SAT (r=-0.46) and VAT (r=-0.67) fat cell weight in the corresponding depot (p<0.0001 for both). Women with visceral adipocyte hypertrophy had higher total-, VLDL-, LDL- and HDL-triglyceride and apoB levels as well as a higher cholesterol/HDL-cholesterol ratio, fasting glucose and insulin levels compared to women with smaller visceral adipocytes. Adjustment for VAT area minimized these differences while subsequent adjustment for attenuation eliminated all differences, with the exception of fasting glycaemia. In SAT, adjustment for VAT area and attenuation eliminated all adipocyte hypertrophy-related alterations except for fasting hyperglycaemia. Conclusion: CT-derived adipose tissue attenuation and area both contribute to explain variation in the cardiometabolic risk profile associated with the same biological parameter: visceral fat cell hypertrophy
Preterm Birth: An Inflammatory Syndrome, Not Just A Myometrial Disorder
Preterm birth (PTB) is the leading cause of neonatal mortality and morbidity. Although the severity of neonatal outcomes is inversely correlated with gestational age, all PTBs can lead to potentially life-threatening neonatal outcomes and major lifelong health complications. Because advances in neonatal care have substantially decreased neonatal mortality, the incidence of PTB and its complications is unabatedly rising. PTB currently affects more than 10% of births worldwide, with similar numbers in developed countries. Correspondingly, improving neonatal outcome is a key objective of the World Health Organization. The recently approved (in Europe) tocolytics drug, Atosiban, used to prolong preterm gestation, has not been shown to improve neonatal outcome, nor have other tocolytic agents used in clinic. Thus, PTB remains an unmet medical need. Recent evidence shows that most, if not all, PTBs are associated with (overt or occult) inflammatory processes in gestational tissues, independent of infection. Pro- inflammatory cytokines are produced from maternal and fetal cells in response to sterile or infectious stressors. These seem to orchestrate a multi-tissue response including myometrial contractility, cervical ripening, and weakening/rupture of fetal membranes, leading to the onset of preterm labor. This integrated system might have been conserved through mammalian evolution due to increased maternal and/or fetal survival when gestation is terminated in specific settings, such as infection. Hence, inflammation may be a common pathway to the numerous aetiologies of PTB. Most importantly, recent evidence suggests that inflammation is transmitted to the fetus, thereby inducing organ injuries that may underlie the development of major neonatal diseases. Targeting inflammation prenatally instead of myometrial contraction could be a more successful and safe approach for the management of PTB, as suggested by recent animal studies.Â
Résumé
La naissance preÌmatureÌe est la principale cause de mortaliteÌ et de morbiditeÌ neÌonatale. Bien que la seÌveÌriteÌ des issus neÌonataux soit inversement correÌleÌe avec lâaÌge gestationnel aÌ la naissance, toutes les naissances preÌmatureÌes peuvent mener aÌ des issus neÌonataux potentiellement mortels et aÌ des complications avec reÌpercussions sâeÌchelonnant sur toute la vie. EÌtant donneÌ que la mortaliteÌ neÌonatale a consideÌrablement diminueÌe avec les reÌcentes avanceÌes en neÌonatalogie, lâincidence de la naissance preÌmatureÌe et de ses complications sont en hausse. La naissance preÌmatureÌe affecte preÌsentement plus de 10% des naissances aÌ travers le monde, avec des taux similaires dans les pays deÌveloppeÌs. ConseÌquemment, dâameÌliorer lâissu neÌonatal est un objectif cleÌ de lâOrganisation Mondiale de la SanteÌ. Le tocolytique Atosiban reÌcemment approuveÌ (en Europe) pour prolonger les gestations preÌ- matureÌes nâa pas deÌmontreÌ dâefficaciteÌ pour ameÌliorer les issus neÌonataux, tout comme les autres tocolytiques utiliseÌs en clinique, et la naissance preÌmatureÌe demeure un besoin meÌdical non-atteint. Des donneÌes reÌcentes deÌmontrent que la plupart, sinon toutes les naissances preÌmatureÌes sont associeÌes avec des processus inflammatoires (francs ou silencieux) dans les tissus gestationnels, indeÌpendamment de lâinfection. Les cytokines pro-inflammatoires sont produites dans les cellules maternelles et fĆtales en reÌponse aÌ des stresseurs steÌriles ou infectieux, et semblent orchestrer une reÌponse multi-tissulaire incluant la contractiliteÌ myomeÌtriale, la preÌparation cervicale, et lâaffaiblissement/rupture des membranes fĆtales, menant au commencement du travail preÌterme. Ce systeÌme inteÌgreÌ pourrait avoir eÌteÌ conserveÌ durant lâeÌvolution mammifeÌre aÌ cause dâune survie accrue de la meÌre et/ou du fĆtus lorsque la gestation est termineÌe dans un contexte speÌcifique, comme lâinfection. Donc, lâinflammation pourrait constituer une voie commune finale pour les nombreuses causes de la naissance preÌmatureÌe. De façon importante, des donneÌes reÌcentes sug- geÌrent que cette inflammation est transmise au fĆtus et en retour induit des dommages aux organes qui pourraient sous-tendre le deÌveloppement de maladies neÌonatales majeures. De cibler lâinflammation en preÌnatal plutoÌt que les contractions myomeÌtriales pourrait constituer une approche seÌcuritaire et plus efficace, comme suggeÌreÌ par de reÌcentes eÌtudes animales.Â
LâĂpargne au QuĂ©bec : sa mesure et son importance, 1981-2006
Parce que les mesures traditionnelles de lâĂ©pargne ne tiennent pas compte de lâĂ©pargne en capital humain et en capital naturel, elles ont tendance Ă sous-estimer systĂ©matiquement le taux dâĂ©pargne national au pays et dans les provinces canadiennes.
Traditionnellement, on dĂ©finit le taux dâĂ©pargne nationale en additionnant lâĂ©pargne financiĂšre des mĂ©nages, des entreprises et des gouvernements et en lâexprimant en pourcentage du PIB sur un territoire donnĂ©. LâĂ©pargne financiĂšre est gĂ©nĂ©ralement obtenue par mĂ©thode rĂ©siduelle, câest-Ă -dire en faisant la diffĂ©rence entre les revenus et les dĂ©penses. Le taux dâĂ©pargne vĂ©ritable ajoute Ă lâĂ©pargne financiĂšre la mesure de lâĂ©pargne en capital humain et soustrait la dĂ©sĂ©pargne en capital naturel non-renouvelable. Bien quâencore imparfaite, la mesure de lâĂ©pargne vĂ©ritable donne un meilleur portrait de lâĂ©pargne sur un territoire.
Le rapport « LâĂ©pargne au QuĂ©bec : sa mesure et son importance, 1981-2006 » fait un survol des diffĂ©rentes mesures de lâĂ©pargne au Canada, au QuĂ©bec et en Ontario. Il prĂ©sente Ă©galement une Ă©valuation de lâĂ©pargne vĂ©ritable au QuĂ©bec et au Canada.
DES DIFFĂRENCES MAJEURES
Lâinclusion du capital humain et du capital naturel aux mesures traditionnelles de lâĂ©pargne a pour effet de modifier substantiellement le portrait de lâĂ©pargne au QuĂ©bec.
Ainsi, lorsquâon compare le taux dâĂ©pargne nationale et le taux dâĂ©pargne vĂ©ritable du QuĂ©bec, on observe que lâĂ©pargne des agents Ă©conomiques quĂ©bĂ©cois en pourcentage du PIB passe du simple au double environ. Par exemple, alors que le taux dâĂ©pargne nationale Ă©tait de 7,42 % au QuĂ©bec en 2005 son taux dâĂ©pargne vĂ©ritable Ă©tait de lâordre de 13,08 % (p. 56 du document principal). En 1997, le taux dâĂ©pargne nationale du QuĂ©bec Ă©tait de 4,49 % alors que son taux dâĂ©pargne vĂ©ritable Ă©tait de 10,27 %. La relation du simple au double sâest maintenue tout au long de la pĂ©riode 1997-2005.
Le concept dâĂ©pargne vĂ©ritable a Ă©tĂ© mis de lâavant par la Banque mondiale. Celle-ci publie un ensemble de statistiques sur lâĂ©pargne vĂ©ritable des pays, mais pas des entitĂ©s sous-nationales. Une validation de la mĂ©thodologie retenue pour calculer le taux dâĂ©pargne vĂ©ritable du QuĂ©bec, mais appliquĂ© aux donnĂ©es canadiennes, a toutefois permis dâĂ©tablir que la divergence entre la mĂ©thode retenue dans le rapport et celle adoptĂ©e par la Banque mondiale nâĂ©tait pas majeure.
Abdominal adipocyte populations in women with visceral obesity
Visceral obesity is independently related to numerous cardiometabolic alterations, with adipose
tissue dysfunction as a central feature. Objective: To examine whether omental (OM) and
subcutaneous (SC) adipocyte size populations in women relate to visceral obesity,
cardiometabolic risk factors and adipocyte lipolysis independent of total adiposity. Design and
Methods: OM and SC fat samples were obtained during gynecological surgery in 60 women
[mean age: 46.1±5.9 years; mean BMI: 27.1±4.5 kg/m2 (range: 20.3-41.1 kg/m2)]. Fresh samples
were treated with osmium tetroxide and were analyzed with a Multisizer Coulter. Cell size
distributions were computed for each sample with exponential and Gaussian function fits.
Results: Computed tomography-measured visceral fat accumulation was the best predictor of
larger cell populations as well as the percentage of small cells in both OM and SC fat (p<0.0000
for all). Accordingly, women with visceral obesity had larger cells in the main population and
higher proportion of small adipocytes independent of total adiposity (pâ€0.05). Using linear
regression analysis, we found that women characterized by larger-than-predicted adipocytes in
either OM or SC adipose tissue presented higher visceral adipose tissue area, increased
percentage of small cells and HOMAir index as well as higher OM adipocyte isoproterenol-,
forskolin- and dibutyryl cAMP- stimulated lipolysis compared to women with smaller-than predicted adipocytes, independent of total adiposity (pâ€0.05). Conclusion: Excess visceral
adipose tissue accumulation is a strong marker of both adipocyte hypertrophy and increased
number of small cells in either fat compartment, which relates to higher insulin resistance index
and lipolytic response, independent of total adiposity
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