This thesis focuses on gynecopathology. It consists of a collection of seven papers published in pathology journals with impact factor. Introduction section contains selection of examples showing scientific application of molecular genetic methods. Further on the aims of individual research projects are described. The first project comprises histomophologic study of skin endometriosis addressing "mullerian" differentiation. A case report of a rare tumor namely borderline papillary serous tumor of the fimbriated end of the fallopian tube follows with molecular genetic analysis of KRAS, BRAF and p53 gene mutation status. Prospective longitudinal study on high grade squamous dysplasia (HSIL) of the cervix in HPV vaccinated women, so called DAV (dysplasia after vaccination), aims to elucidate pathogenesis of this phenomenon. Two other studies focus on incidence of fumarate hydratase deficient leiomyomas of the uterus and hereditary leiomyomatosis and renal cell carcinoma syndrome (HLRCC). The aim of those studies is to improve our diagnostic capability and increase detection rate of the patients with HLRCC syndrome. Finally a new subtype of HSIL namely bizarre cell dysplasia is described in two separate studies. Conclusion remarks contemplate the role of molecular genetics in surgical pathology.

La polyneuropathie sensitivomotrice héréditaire (PNSMH) est une maladie rare qui entraîne un ralentissement du développement moteur et mental, une déficience sensitivomotrice et des syndromes neuropsychiatriques, et qui s’accompagne souvent d’une agénésie du corps calleux. Par ailleurs, plusieurs évaluations rapportent une petite stature ou une masse corporelle anormalement basse chez les patients. La PNSMH est causée par des mutations perte de fonction du cotransporteur K⁺-Cl⁻ de type 3 (KCC3). Des évaluations cliniques détaillées et la caractérisation de souris inactivées pour Kcc3 (Kcc3ᴷᴼ) ont permis d’établir qu’un défaut d’export K⁺-Cl⁻ cause les atteintes neurologiques anatomiques et fonctionnelles dans la maladie. Chez les souris Kcc3ᴷᴼ, des manifestations extraneurologiques ont également été relevées : masse corporelle réduite, pression artérielle (PA) élevée, polydipsie et polyurie. Puisque la physiopathologie des désordres extraneurologiques découlant de la perte de fonction de KCC3 reste incomplètement décrite, mes travaux avaient pour objectif d’en comprendre les mécanismes sous-jacents en utilisant un modèle Kcc3ᴷᴼ. Une caractérisation initiale de notre lignée de souris Kcc3ᴷᴼ constitutive et systémique a montré des anomalies vasculaires et cardiaques accompagnant une élévation de PA diastolique. Cette lignée affichait également une polydipsie et une polyurie isoosmotique, de même qu’une réduction de masse corporelle et d’adiposité sans réduction d’apport alimentaire. Une caractérisation métabolique détaillée de notre modèle a ensuite permis de révéler des réductions de masse grasse et de masse maigre. Cette minceur résulte sûrement en partie des augmentations d’activité locomotrice et de dépense énergétique mesurées. Une nette amélioration de la tolérance au glucose a aussi été trouvée, ainsi que des concentrations réduites de triacylglycérols plasmatiques. Enfin, nous avons noté que notre modèle est résistant à l’obésité induite par une diète hyperlipidique et affiche une élévation concomitante de l’expression d’enzymes lipogéniques et lipolytiques dans le gras viscéral, engendrant potentiellement une dissipation calorique. En revisitant la fonction cardiovasculaire dans notre modèle par des méthodes de pointe, nous n’avons pas observé de changement de PA ni de différence de réactivité artériolaire en conditions basales, mais nous avons noté une élévation de distensibilité artériolaire passive. Chez notre modèle, nous n’avons pas non plus remarqué de sensibilité particulière de la PA au sel alimentaire, mais une excrétion urinaire fortement accrue de solutés sous diète hypersodée ainsi qu’une préférence marquée pour le sel. Ces observations sont compatibles avec un défaut de réabsorption hydrosodée par le rein pouvant d’ailleurs prévenir les élévations de PA. En somme, nos travaux ont permis de mieux comprendre les atteintes cardiométaboliques qui accompagnent le tableau neurologique d’un modèle murin de PNSMH. Nous avons notamment relevé des bénéfices inattendus dans le métabolisme glucidique et lipidique suivant l’inactivation de Kcc3. Nous soupçonnons également que l’absence de KCC3 dans le rein engendre une fuite ionique urinaire s’accentuant sous diète hypersodée et pouvant influencer la PA en limitant l’expansion volémique. Nos observations d’anomalies pléiotropiques liées à l’inactivation de Kcc3 font de ce gène une nouvelle cible pharmacologique potentielle et justifient la nécessité d’étudier l’anatomophysiologie cardiométabolique des patients atteints de PNSMH de façon plus approfondie. / Hereditary motor and sensory neuropathy (HMSN) is a rare disease that leads to delayed motor and mental development, loss of sensory and motor function and neuropsychiatric syndromes, and that is often accompanied by partial or complete agenesis of the corpus callosum. Additionally, several cases of short stature or low body weight have been reported in patients. HMSN is caused by loss-of-function mutations in K⁺-Cl⁻ cotransporter type 3 (KCC3). Detailed clinical reports and characterizations of mice inactivated for Kcc3 (Kcc3ᴷᴼ) have allowed to establish that defective K⁺-Cl⁻ export causes the anatomical and functional neurologic impairments in the disease. In Kcc3ᴷᴼ mice, extra-neurological abnormalities have also been noted: lower body weight, high blood pressure (BP), polydipsia and polyuria. Because the pathophysiology of extra-neurological traits arising from KCC3 loss of function remains incompletely described, my work aimed at understanding the mechanisms at play using a Kcc3ᴷᴼ model. An initial characterization of a constitutive and systemic Kcc3ᴷᴼ mouse line showed vascular and cardiac abnormalities along with a rise in diastolic BP. This model also showed polydipsia and iso-osmolar polyuria along with reduced body weight and adiposity but no decrease in food intake. A detailed metabolic characterization of our model further revealed reductions in fat and lean body masses. This leanness results certainly in part from increased locomotor activity and energy expenditure as measured. A marked improvement in glucose tolerance was also found in addition to lower plasmatic triglyceride concentrations. Lastly, we also demonstrated that our model is resistant to high-fat-diet-induced obesity and shows concomitant increase in expression of both lipogenic and lipolytic enzymes in visceral fat, thereby potentially generating caloric dissipation. When revisiting the cardiovascular function of our model with cutting-edge methods, we measured normal BP and arteriolar reactivity in baseline conditions. However, we noted an increase in passive arteriolar distensibility. In our model, we did not notice sensitivity of BP to dietary salt but found a marked increase in urinary solute excretion under high-salt diet and a strong preference for salt. These observations are consistent with a defect in hydromineral reabsorption by the nephron that may prevent BP from rising. In short, our work allowed to better understand the cardiometabolic characteristics that accompany the neurologic portrait of an HMSN mouse model. In particular, we noted unexpected benefits in carbohydrate and lipid metabolism upon Kcc3 inactivation. We also suspect that KCC3 ablation in the kidney leads to urinary hydromineral wasting that can be more salient under dietary salt loading and can influence BP by blunting extracellular volume expansion. The pleiotropic abnormalities arising from Kcc3 inactivation identify this gene as a new potential pharmacological target and argue for improving efforts at describing the cardiometabolic features of patients with HMSN.

Andrew Michael Ramsay fut un intellectuel écossais du Siècle des Lumières, à la fois "aventurier religieux", auteur politique et franc-maçon. Élevé dans le protestantisme, il rechercha un équilibre spirituel et une doctrine plus conformes à ses vœux. Il voyagea dans de nombreux pays pour atteindre ce but et finalement trouva auprès de Fénelon, archevêque de Cambrai, et de Madame Guyon, adepte du "Pur Amour", un père et une mère spirituels. Sous leur influence, il finit par adhérer à un catholicisme de nature gallicane caractérisé par un appel constant à l’intériorité. De son œuvre, émergent quatre traités : l’Essai sur le gouvernement civil(1721) dans lequel il démontre que la meilleure forme de gouvernement est la monarchie absolue, héréditaire, de droit divin. Fervent jacobite, il espérait le retour de la dynastie Stuart sur le trône d’Angleterre. L’Histoire de la vie de Fénelon (1727) traite principalement des péripéties de sa conversion par le prélat; Les Voyages de Cyrus (1727), roman didactique, apologétique et politique, raconte la formation d’un jeune prince accompli, rempli de sagesse et de piété. Son ouvrage central, Les principes philosophiques de la religion naturelle et révélée (1749), communément appelé le "Great Work" ne parut qu’après sa mort. Le franc-maçon perçait alors sous le philosophe. Son Discours (1737) fait remonter les origines de l’Ordre aux croisades et, surtout, fixe les obligations auxquelles est soumis tout franc-maçon, qui lui sont rappelées au moment de son initiation. Cet homme, complexe, mystique et politique réussit l’exploit de faire changer radicalement cette organisation très attachée à ses traditions qu’est la Franc-maçonnerie. / Andrew Michael Ramsay was a Scottish intellectual of the Enlightenment and was at the same time a "religious adventurer", a political author and a freemason. Born into a Protestant family, he undertook a search for spiritual stability and for a doctrine more in line with his aspirations. In this quest, he journeyed through several countries, and he eventually found in the company of Fénelon, archbishop of Cambrai, and of Madame Guyon, an advocate of the doctrine of "Pure Love", a spiritual father and mother. Inspired by them, he finally converted to a Gallican variety of Catholicism which was at the root of his call to a life of constant soul-searching. From his work four treatises emerge: An Essay upon Civil Government (1721), in which he sought to show that the best form of government is an absolute, hereditary monarchy, based on divine right. As a zealous Jacobite, he longed for the return of the Stuarts to the British throne. The Life of Fénelon (1727) deals mainly with the various stages leading up to his conversion by the prelate. The Travel of Cyrus (1727) is a didactic, apologetic and political novel which relates the education of a young accomplished prince endowed with wisdom and piety. His most considerable work is The Philosophical Principles of Natural and Revealed Religion (1749), commonly called the "Great Work", which was published posthumously. Here the freemason can be seen beneath the philosopher. His Discourse (1737) traces the origins of Freemasonry back to the crusades, and also sets out the obligations that every freemason must adhere to and which he is reminded of during his initiation. His success in radically changing this organization so deeply attached to its customs remains the lasting legacy of this complex, mystical and political figure who is Andrew Michael Ramsay.

Background & Aims: Despite advances in surgical care and chemotherapeutic regimens, the five-year survival rate for Stage IV Hepatoblastoma (HB), the predominant pediatric liver tumor, remains at 27%. YAP1 and β-Catenin co-activation occurs in 80% of children’s HB; however, a lack of conditional genetic models precludes exploration of tumor maintenance and therapeutic targets. Thus, the clinical need for a targeted therapy remains unmet. Given the predominance of YAP1 and β-catenin activation in children’s tumors, I sought to evaluate YAP1 as a therapeutic target in HB. Approach & Results: Herein, I engineered the first conditional murine model of HB using hydrodynamic injection to deliver transposon plasmids encoding inducible YAP1S127A, constitutive β-CateninDelN90, and a luciferase reporter to murine liver. Tumor regression was evaluated using in vivo bioluminescent imaging, and tumor landscape characterized using RNA sequencing, ATAC sequencing and DNA foot-printing. Here I show that YAP1 withdrawal in mice mediates >90% tumor regression with survival for 230+ days. Mechanistically, YAP1 withdrawal promotes apoptosis in a subset of tumor cells and in remaining cells induces a cell fate switch driving therapeutic differentiation of HB tumors into Ki-67 negative “hbHep cells.” hbHep cells have hepatocyte-like morphology and partially restored mature hepatocyte gene expression. YAP1 withdrawal drives formation of hbHeps by modulating liver differentiation transcription factor (TF) occupancy. Indeed, tumor-derived hbHeps, consistent with their reprogrammed transcriptional landscape, regain partial hepatocyte function and can rescue liver damage in mice. Conclusions: YAP1 withdrawal, without modulation of oncogenic β-Catenin, significantly regresses hepatoblastoma, providing the first in vivo data to support YAP1 as a therapeutic target for HB. Modulating YAP1 expression alone is sufficient to drive long-term regression in hepatoblastoma because it promotes cell death in a subset of tumor cells and modulates transcription factor occupancy to reverse the fate of residual tumor cells to mimic functional hepatocytes.

Introduction: Central Line-Associated Bloodstream Infections (CLABSIs) are a major cause of increased mortality, morbidity and healthcare costs in neonatal intensive care units (NICUs) patients. Despite CDC's efforts to reduce infection rates, patients often suffer consequences. The objective of this study is to perform a systematic review of strategies utilized in the neonatal population and evaluate them with the current CDC's guidelines to assess the effectiveness of bundles in preventing CLABSI in NICUs. Methods: A systematic literature search was conducted using CINAHL Plus with Text, Cochrane Database of Systematic Reviews and MEDLINE from January 2008 up to 2018. There were multiple search terms used and these included "neonate OR newborn OR infant", "CLABSI OR central line-associated bloodstream infection", "intervention OR prevention" and "bundle". The search solely focused on the outcome of infant patients. Therefore studies were excluded for the following criteria: being non-peer reviewed, being published before 2008, and being a case in which CLABSI was assessed in patients outside the NICU. See Table 4 and 5 for further information. Results: Eight articles were eligible for inclusion all of which CDC's guidelines were implemented in their strategy of intervention. The systematic review showed that adherence to care bundles decreases infection rates drastically. All eight articles reported a significant decrease in CLABSI rates following the implementation of the bundle set by CDC with two studies achieving a CLABSI rate of zero. Author's Conclusion: Implementation of care bundles showed a success in reducing CLABSI rates in the NICUs; however none of the studies endorsed a specific bundle application utilized to achieve its intended goal. Some practices adopted CDC's guidelines more than others and those showed a greater decrease in infection rate. In addition, it is evident that nurses deliver the best care when preventing an infection. Further research is needed to assess the effectiveness of a specific bundle element.

ABSTRACT The porphyrias are a diverse group of metabolic disorders arising from diminished activity of enzymes in the heme biosynthetic pathway. They can present with acute neurovisceral symptoms, cutaneous symptoms, or both. The complexity of these disorders is demonstrated by the fact that some acute porphyria patients with the underlying genetic defect(s) are latent and asymptomatic while others present with severe symptoms. This indicates that there is at least one other risk factor required in addition to the genetic defect for symptom manifestation. A systematic review of the heme biosynthetic pathway highlighted the involvement of a number of micronutrient cofactors. An exhaustive review of the medical literature uncovered numerous reports of micronutrient deficiencies in the porphyrias as well as successful case reports of treatments with micronutrients. Many micronutrient deficiencies present with symptoms similar to those in porphyria, in particular vitamin B6. It is hypothesized that a vitamin B6 deficiency and related micronutrient deficiencies may play a major role in the pathogenesis of the acute porphyrias. In order to further investigate the porphyrias, a computational model of the heme biosynthetic pathway was developed based on kinetic parameters derived from a careful analysis of the literature. This model demonstrated aspects of normal heme biosynthesis and illustrated some of the disordered biochemistry of acute intermittent porphyria (AIP). The testing of this model highlighted the modifications necessary to develop a more comprehensive model with the potential to investigated hypotheses of the disordered biochemistry of the porphyrias as well as the discovery of new methods of treatment and symptom control. It is concluded that vitamin B6 deficiency might be the risk factor necessary in conjunction with the genetic defect to trigger porphyria symptoms.