Chémoréflexes laryngés en période néonatale influence de la prématurité et d'une exposition post-natale à la fumée secondaire

Les reflux laryngo-pharyngés acides, très fréquents en période néonatale, sont la remontée du contenu gastrique jusqu'au niveau du pharynx. Le contact entre un liquide (ex : liquide gastrique acide) et le larynx déclenche chez un nouveau-né à terme et en santé des mécanismes de défense (toux, déglutition, réaction d'éveil) appelés chémoréflexes laryngés, dont l'objectif est d'empêcher l'aspiration dans la trachée. Malheureusement, chez certains nouveau-nés, le contact entre le liquide et la muqueuse laryngée déclenche des réflexes délétères comprenant des apnées, des bradycardies et désaturations. Ces réflexes délétères sont impliqués dans les apnées du prématuré, les malaises graves du nourrisson et probablement dans certains cas du syndrome de mort subite du nourrisson.Les observations cliniques suggèrent que certaines conditions néonatales, dont la prématurité et une exposition post-natale à la fumée secondaire, favorisent la survenue de ces réflexes délétères. Ainsi, mon projet de doctorat consiste à étudier l'influence de la prématurité et l'influence d'une exposition à la fumée secondaire sur les CRL chez l'agneau nouveau-né. L'influence de la prématurité a été effectuée en utilisant un modèle d'agneau prématuré à 132 jours de gestation (terme = 147 jours). L'influence d'une exposition à la fumée secondaire post-natale, a, quant à elle, été effectuée en utilisant un modèle d'agneau exposé à la fumée secondaire durant les 16 premiers jours de vie à raison de 20 cigarettes/jour. Dans chaque étude, les agneaux ont été instrumentés pour enregistrer l'activité du muscle constricteur du larynx (muscle thyroaryténoidien), l'électroencéphalogramme, la fréquence cardiaque, la respiration et la saturation. Un cathéter supra-glottique a été utilisé pour l'injection de 0.5 ml de différentes solutions (modèle de prématuré : injection de sérum physiologique, d'eau distillée et HCl, pH 2; modèle d'exposition à la fumée secondaire : injection de sérum physiologique, d'eau distillée, HCl pH 2, lait) durant les différents stades de conscience. Le modèle d'agneau prématuré a permis de démontrer qu'une stimulation laryngée soit par l'eau distillée ou HCl à 7 jour post-natal induit des apnées prolongées, des bradycardies et des désaturations, lesquels sont potentiellement dangereuses. À l'inverse, une stimulation laryngée à 14 jours post-natals n'induit pas d'évènement cardiorespiratoire cliniquement significatif. Le modèle d'exposition à la fumée secondaire a, quant à lui, permis de démontrer qu'une exposition post-natale à la fumée secondaire induit une inhibition cardiorespiratoire plus importante et diminue les mécanismes de protection suite à une stimulation laryngée. Par contre, aucune stimulation n'entraîne d'évènement pouvant mettre en péril la vie de l'agneau. En conclusion, la survenue de réflexe potentiellement dangereux suite à une stimulation laryngée semble survenir en présence de certaines conditions néonatales. La prématurité semble être une de ces conditions.Les évènements potentiellement dangereux observés chez les agneaux prématurés montrent que les CRL sont probablement impliqués dans la pathogénèse des apnées/bradycardies du prématuré, phénomène fréquemment retrouvés en clinique. Quant à l'exposition à la fumée secondaire, elle est une condition néonatale qui modifie les réflexes obtenus suite à une stimulation laryngée sans induire de réflexes potentiellement dangereux.Les modifications observées suggèrent fortement que la fumée secondaire est un facteur de risque des malaises inopinés du nouveau-né et du syndrome de mort subite du nourrisson

Chémoréflexes laryngés induits par l'acide, l'eau vs le salin chez les agneaux nouveau-nés durant le sommeil calme

Mise en contexte : Les chémoréflexes laryngés (CRI) sont déclenchés suite au contact entre un liquide et la muqueuse laryngée. Chez un organisme mature, ces CRL sont responsables de mécanismes de protection des voies aériennes inférieures (VAI) tels que déglutitions, toux et réaction d'éveil afin d'éviter l'aspiration. Par contre, chez un organisme immature comme c'est le cas chez les nouveau-nés, ces CRL associent apnée, bradycardie, laryngospasme, hypertension et redistribution du débit sanguin. En période néonatale, ces CRL, déclenchés en réponse à un reflux gastro-oesophagien acide, sont tenus responsables d'apnées du prématuré, de malaises graves du nourrisson (ALTE) et probablement de quelques cas de mort subite du nourrisson (MSN). Malgré leur pertinence clinique évidente, la revue de la littérature permet de constater que de nombreuses questions persistent concernant les CRL, principalement parce que les conditions expérimentales des études antérieures ne reflètent pas ce qui est vu en clinique. Ainsi, les CRL ont été étudiés le plus souvent en utilisant des modèles anesthésiés, en utilisant l'eau distillée, en se servant d'une trachéotomie pour l'injection des solutions et finalement en ne prenant pas en compte les stades de conscience. Une meilleure compréhension des CRL, en particulier déclenchés par des solutions acides, est donc nécessaire. But du projet : Le but de ce travail est d'étudier les CRL chez l'agneau nouveau-né sans sédation en réponse à l'acide, en comparaison à l'eau distillée et au salin durant le sommeil calme

The Codification of Human Rights in Canada

Abstract : This article is an updated and slightly revised version of the national report submitted by the author to the International Academy of Comparative Law's Second Thematic Congress. The theme of the Congress, held from May 24th to 26th 2012 at the National Taiwan University, was "Codification". The paper offers a systematic but brief account of the adjudicative protection of human rights, both collective and individual, in domestic law. Such an overview also provides the opportunity to identify a few trends in the development of the Canadian constitutional case law regarding human rights. Even if human rights had received quasi-constitutional protection several decades earlier, their codification as part of the supreme law of Canada in 1982 proved to be a significant step forward. This is particularly true for the fundamental freedoms of expression and religion, and for “legal rights.” The picture is more mixed, however, regarding democratic rights. Part II of the Constitution Act, 1982, relating to special rights of Aboriginal peoples, has had huge systemic repercussions. A notable source of concern is the Supreme Court’s continued hesitance on how to conceive of the relation between the Charter’s individual rights and freedoms and the special rights of Aboriginal peoples recognized in Part II of the C.A. 1982.Résumé : L’article qui suit est une version corrigée, mise à jour et légèrement remaniée du rapport national canadien produit au deuxième congrès thématique de l’Académie internationale de droit comparé. Ce congrès, qui fut tenu à l’université nationale de Taiwan du 24 au 26 mai 2012, avait pour thème « La Codification ». Le texte qui suit offre donc une présentation à la fois systématique et brève de la protection juridictionnelle des droits fondamentaux, collectifs comme individuels, en droit interne. De dresser un tel panorama devait du reste permettre de dégager certaines tendances d’évolution de la jurisprudence constitutionnelle canadienne relative aux droits fondamentaux. Même si la protection « quasi constitutionnelle » de ceux-ci y était alors réalité depuis quelques décennies, la « codification » des droits de la personne au sein de la « loi suprême » du Canada en 1982 devait se révéler comme un progrès considérable. Cela concerne au premier chef les libertés fondamentales de religion et d’expression ainsi que les « garanties juridiques ». Le bilan est plus mitigé en ce qui concerne les droits démocratiques. La Partie II de la Loi constitutionnelle de 1982, relative aux droits spéciaux des peuples autochtones, a eu des répercussions systémiques énormes. Une source d’inquiétude est l’hésitation dont continue de faire montre la Cour suprême sur la question de la manière dont il convient de concevoir la relation entre les droits et libertés que la Charte garantit à la personne et les droits que la Partie II de la L.C. 1982 reconnaît en propre aux peuples autochtones

Effect of sensory-based intervention on the increased use of food-related descriptive terms among restrained eaters

The goals of this pilot randomized controlled trial were to investigate and determine whether sensorybased intervention influenced the number and type of terms (descriptive and hedonic) used by restrained women to describe a certain food, and whether changes in the number of descriptive terms were associated with changes in intuitive eating. We collected data at baseline (T = 1), at the end of the intervention period (T = 2), and at 12 weeks post-intervention (T = 3) using the descriptive form and Intuitive Eating Scale (IES). At T = 1, 50 women were randomly assigned to an intervention group (sensory-based intervention) or a control group (waiting list). To determine the effect of intervention over time on the number of descriptive and hedonic terms, we conducted statistical analyses using mixed models. To determine associations between Intuitive Eating Scale subscales and the number of descriptive terms, we also calculated Spearman correlation coefficients. We noted a significant group-by-time interaction for descriptive terms associated with all senses (p < 0.04), except for a sight-related trend (p = 0.06). In comparison with T = 1, intervention group women at T = 2 and T = 3 showed a significant increase in descriptive terms associated with smell (p = 0.0002 and p = 0.03, respectively), taste (p = 0.001 and p = 0.01, respectively) and hearing (p = 0.04 and p = 0.0003, respectively). Among intervention group women, we noted a positive correlation between changes (T = 3 vs. T = 2) in the number of descriptive terms used and changes in reliance on internal hunger and satiety cues (r = 0.48; p = 0.04), as well as between changes (T = 3 vs. T = 1) in the number of descriptive terms used and changes in unconditional permission to eat (r = 0.45; p = 0.05). Overall, these data show that sensory-based intervention may help restrained women become more objective and enjoyably connected to food and their own bodies, which may promote a more intuitive approach to eating

Effects of postnatal smoke exposure on laryngeal chemoreflexes in newborn lambs

Laryngeal chemoreflexes (LCR), which are elicited by the contact of liquids such as gastric refluxate with laryngeal mucosa, may trigger some cases of sudden infant death syndrome. Indeed, while LCR in mature mammals consist in lower airway protective responses, previous animal data have shown that LCR in immature newborns can include laryngospasm, apnea, bradycardia and desaturation. The present study was aimed at testing the hypothesis that postnatal exposure to cigarette smoke is responsible for enhancing cardiorespiratory inhibition observed with LCR. Eight lambs were exposed to cigarette smoke (20 cig/day) during 16 days and compared to seven control lambs. Urinary cotinine/creatinine ratio was measured at a level relevant to previously published levels in infants. On D15-D16, 0.5 ml of HCl (pH 2), milk, distilled water or saline was injected onto the larynx via a chronic supra-glottal catheter during sleep. Results showed that exposure to cigarette smoke significantly enhanced apneas and bradycardias during LCR while significantly decreasing swallowing and arousal. These results were observed independently of the state of alertness and of the experimental solution tested. In conclusion, 15 day-postnatal exposure to cigarette smoke increases cardiorespiratory inhibition and decreases lower airway protective mechanisms in non-sedated, full-term lambs

Validation of a new automatic smoking machine to study the effects of cigarette smoke in newborn lambs

The aim of this study was to describe the characteristics and validate the use of a new, custom-built automatic smoking machine (ASM), primarily designed to study the effects of an environmental tobacco smoke surrogate (ETS surrogate) exposure in animals of various sizes, including large animals. The equipment includes a programmable ASM coupled to a vented whole body chamber, where animals can be exposed to both mainstream and sidestream smoke. The user-friendly interface allows for full programming of puff volume (1-60 mL), time interval between two puffs (1-60 s) and between two cigarettes (1-60 min). Eight newborn lambs were exposed to either 10 (4 lambs, C10 group) or 20 (4 lambs, C20 group) cigarettes, 8 h per day for 15 days. Four additional control, lambs were exposed to air (C0 group). Weight gain was identical in all three groups of lambs. Urinary cotinine/creatinine ratio increased with the number of cigarettes smoked (C0: 11 ± 7 ng/mg; C10: 961 ± 539 ng/mg; C20: 1821 ± 312 ng/mg), with levels in the C10 and C20 groups in keeping with values published in infants exposed to ETS. Overall, results show that our new ASM is especially well suited for ETS surrogate exposure in non-restrained, non-anaesthetized large animals such as sheep

Radio telemetry devices to monitor breathing in non-sedated animals

Radio telemetry equipment has significantly improved over the last 10-15 years and is increasingly being used in research for monitoring a variety of physiological parameters in non-sedated animals. The aim of this review is to provide an update on the current state of development of radio telemetry for recording respiration. Our literature review found only rare reports of respiratory studies via radio telemetry. Much of this article will hence report our experience with our custom-built radio telemetry devices designed for recording respiratory signals, together with numerous other physiological signals in lambs. Our current radio telemetry system allows to record 24 simultaneous signals 24h/day for several days. To our knowledge, this is the highest number of physiological signals, which can be recorded wirelessly. Our devices have been invaluable for studying respiration in our ovine models of preterm birth, reflux laryngitis, postnatal exposure to cigarette smoke, respiratory syncytial virus infection and nasal ventilation, all of which are relevant to neonatal respiratory problems

The cross-fertilization of jurisprudence and the principle of proportionality : process and result from a canadian perspective

Modern comparative constitutionalism traces back at least to the practice of some states in the post-World War II era of adopting democratic regimes as well as constitutionally entrenched bills of rights. It has since been fueled by the proliferation of international human rights instruments, which has increased with the end of the Cold War. Significant attention was first paid to comparative constitutional structure, but many states have now reached another stage. As notably witnessed by the works of the Council of Europe and especially those of the Venice Commission in the domain of constitutional justice, the question now is no longer about constitutionalism, including whether rights should be constitutionally protected, as much as it is about constitutional justice: how to effectively implement constitutions. Both on a regional and a global level, mutual inspiration is increasingly drawn from the case-law of peer Courts of other countries and even other continents, which gives rise to a cross-fertilisation phenomenon. One constitutional principle that emerges from, and which is still being forged by, such cross-fertilisation is the principle according to which the limitation of human rights and freedoms must be proportional to states’ objectives, that is, the principle of proportionality. More specifically, our topic is about both the historical process of jurisprudential cross-fertilisation and its functional result as far as the principle of proportionality is concerned. We speak from a Canadian perspective. The aim here is to be able to distinguish between what is common and what is distinctive about the Canadian approach

Effects of postnatal environmental tobacco smoke on non-nutritive swallowing-breathing coordination in newborn lambs

While prenatal environmental tobacco smoke (ETS) exposure is a well-known risk factor for sudden infant death syndrome, the effect of postnatal ETS exposure is less clear. The objective of this study was to investigate the effect of postnatal ETS exposure on non-nutritive swallowing (NNS) and NNS-breathing coordination, which are crucial to prevent aspiration related-cardiorespiratory events. Eighteen newborn lambs (6 per group) were randomly exposed to either 10 cigarettes/day, 20 cigarettes/day or room air for 15 days. Lambs were instrumented for recording states of alertness, swallowing, electrocardiogram and breathing; recordings were performed in non-sedated lambs at the end of ETS exposure. Urinary cotinine/creatinine ratio confirmed relevant real-life exposure. Postnatal ETS exposure had no effect on NNS frequency but tended to decrease inspiratory NNS (p=0.07) during quiet sleep. No effect on respiratory or heart rate (p>0.6), apnea index (p=0.2) or sleep states (p=0.3) was observed. In conclusion, postnatal ETS exposure in lambs had only mild effects on NNS-breathing coordination