Vitamine A et Organogenèse Rénale (identification de nouveaux marqueurs du développement rénal)

Le développement du métanéphros repose sur des interactions moléculaires complexes entre le bourgeon urétéral et le mésenchyme métanéphrique, aboutissant à la formation des canaux collecteurs pour le premier et à la conversion en néphrons du second. La vitamine A par l'intermédiaire de son métabolite actif l'acide rétinoïque, contrôle de manière dose dépendante l'organogenèse rénale. Le but de ce travail de thèse a été d'une part, d'analyser lors d e la néphrogenèse, la répartition cellulaire des enzymes impliquées dans la synthèse (Aldéhyde deshydrogénases Aldh1a1 à 4) et la dégradation de l'acide rétinoïque (Cytochrome P450 26A1 et Bl, Cyp26A1 et B1) et d'autre part, de rechercher de gène différentiellement exprimes après stimulation in vitro de la n éphrogenèse par l'acide rétinoïque. Ainsi nous avons identifié trois gènes, Mortaline-2, Myotrophine et Attractine-like, comme étant de nouveaux marqueurs du développement rénal et ayant une expression sensible à l'acide rétinoïque.PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Modélisation des perturbations électromagnétiques dans les convertisseurs statiques pour des applications aéronautiques

Depuis les années 1990, l énergie électrique a tendance à supplanter les autres énergies de servitude à bord des avions. Ceci offre des gains notables en termes de poids, volume et coûts de maintenance. L'énergie électrique remplit des fonctions de plus en plus variées grâce à la généralisation de l'utilisation de convertisseurs statiques. Ces convertisseurs sont basés sur l'utilisation de composants semiconducteurs en commutation qui génèrent des variations rapides de tension et de courant. Ce qui engendre des perturbations à haute fréquence qu'il faut limiter afin d'être conforme aux normes de compatibilité électromagnétiques (CEM). La conformité aux normes est souvent obtenue en ajoutant un filtre lourd et volumineux au système, ce qui réduit les gains apportés par la transition vers le plus électrique. Afin d'optimiser le filtre à ajouter, il est intéressant de prendre en compte la contrainte de CEM dès la phase de conception, pour cela, il faut disposer d'outil de simulation prédictive. Dans cette thèse nous proposons une méthode de modélisation des perturbations conduites émises par un système valable jusque 50MHz. Pour cela, notre travail se divise en deux parties. D'une part, nous proposons une méthode de modélisation des chemins de propagation des perturbations, incluant notamment les câbles d'énergie. D'autre part, nous proposons une méthode de modélisation des sources de perturbation en domaine fréquentiel. Cette méthode est basée sur l'utilisation de plusieurs topologies de générateurs équivalents et permet de représenter le comportement non-linéaire des convertisseurs. Cette méthode est validée expérimentalement sur un hacheur série et sur un onduleur monophasé.Since the 1990 s, electricital energy tends to replace pneumatic and hydraulic energy aboard aircrafts. This allows to reduce weight, volume and maintenance costs of the actuators. Electrical energy is used for more and more variated functions thanks to the generalization of the power converters. These power converters are based on the use of semiconductor devices in switching mode which generates sharp voltage and current variations. This leads to electromagnetic (EMC) issues. In order to obtain the compliance to EMC standards, a heavy and bulky filter is often added to the system, which lower the gain allowed by the transition to electrical energy. In order to optimize the filter added, it is interesting to take into account the EMC at the design step. Thus it is necessary to have a predictive modeling tool. In this thesis, a modeling method of the conducted electromagnetic interference (EMI) emitted valid up to 50MHz by a system is proposed. Thus our work is devided into two parts. First, we propose a modeling method of the propagation paths including power cable. Then, we propose a modeling method of the EMI sources in frequency domain. This method is based on the use of multiple equivalent generators topologies and allows to retranscript the non-linear behaviour of the converters. This method is experimentally validated on a buck-converter and a single phased inverter.LILLE1-Bib. Electronique (590099901) / SudocSudocFranceF

Zag Expression during Aging Suppresses Proliferation after Kidney Injury

Recovery after acute kidney injury is impaired in the elderly, but mechanistic information regarding why this occurs is limited. In this study, aged mouse kidneys displayed a reduced epithelial proliferative reserve in vivo and in vitro. Microarray analysis identified increased expression of zinc-α (2)-glycoprotein (Zag) in aged proximal tubular cells. The addition of recombinant Zag to primary renal epithelial cell cultures decreased proliferation, whereas knockdown of Zag increased proliferation. In vivo, systemic small interference RNA suppressed expression of Zag in the mouse proximal tubule; this increased the rate of epithelial cell proliferation after renal ischemia/reperfusion in aged mice but also increased parenchymal fibrosis. These results demonstrate that increased Zag expression in the aged kidney acts to suppress the proliferative response to injury and introduce Zag as a modifier of the aging phenotype

Tangible interactions in control centres for railway traffic management

International audienceA current trend in rail industry control centres is to move towards an increase in the number of digitaltools to assist operators. Our observations show that the information used by rail controllers is distributedamong different interfaces. Operators must assemble all this information themselves to understand thestate of the system. This task is often done mentally, resulting in difficult information sharing and aslower decision process. It is in this search for improvement of the operational centres that we realizeda prototype of a tangible touch table presented in this article. The first tests are underway and allowus to have rather positive feedback on this technology that operators are not familiar with. The nextiterations will focus on refining the prototype and on experimenting with a larger group of users

Diode laser surgery in a 2-year- old doe with progesterone receptor free vaginal varicose veins

peer reviewedGenital vascular abnormalities described in rabbits are a rare condi-tion and almost exclusively endometrial veinous aneurysms. They are incidental findings unless they are ruptured leading to a life-threatening vaginal bleeding. A 2-year-old female intact Bleu de Ham rabbit was presented with a 2 cm soft purple mass protruding from the vulva and a vaginitis. Under general anaestesia (dexmedetomidine, ketamine, mi-dazolam intramuscularly, propofol, fentanyl intravenously and isoflu-rane gas via an endotracheal tube), this mass and a second one present cranially in the vagina were resected through a ventral episiotomy. A partial thickness incision was made around their pedicles with a surgi-cal diode laser. The doe received meloxicam, buprenorphine, tramadol, metoclopramide, aluminium phosphate post surgery. Trimetoprim sul-famide was added because of purulent rhinitis. Six months after mass removal, the doe was ovariohysterectomized, and no sign of recurrence was observed. The animal was euthanized 6 months later because of gastric stasis, and recurrences were present in the vagina. At histologi-cal examination, both the primary and the recurring lesions were di-agnosed as voluminous varicose veins, and the only uterine anomaly that was found was cystic endometrial hyperplasia. Immunochemistry failed to identify progesterone receptors on the vaginal lesions. Recurrence after ovariohysterectomy and the absence of progesterone receptors in this case suggest that sex hormones are not involved in the etiopathogenesis of vaginal varicose veins in rabbits while they are strongly suspected in vulvar varicose veins in pregnant women. This is the first detailed report of a vaginal localization of varicose veins in a female rabbit and their surgical removal with the aid of a diode laser

Erythropoietin expands a stromal cell population that can mediate renoprotection

Recent studies have demonstrated that erythropoietin (EPO) receptors are expressed on tubular epithelial cells and that EPO can protect tubular cells from injury in vitro and in vivo. Separate studies have demonstrated that marrow stromal cells (MSCs) exert a renoprotective effect in ischemia-reperfusion and cisplatin tubular injury via the secretion of factors that reduce apoptosis and increase proliferation of tubular epithelial cells. In the present study we demonstrate that MSCs express EPO receptors and that EPO can protect MSCs from serum deprivation-induced cell death and can stimulate MSC proliferation in vitro. The administration of EPO to mice resulted in the expansion of CD45-Flk1-CD105+ MSCs in the bone marrow and in the spleen and mobilized these cells as well as CD45-Flk1+ endothelial progenitor cells into the peripheral circulation. Consistent with previous reports, the administration of EPO diminished the decline in renal function associated with cisplatin administration. This effect was partially reproduced by intraperitoneal injection of cultured EPO-mobilized cells in cisplatin-treated mice. Thus the in vivo expansion and/or activation of these cells may contribute to the renoprotective effects of EPO to protect tubular cells from toxic injury

In vivo expression of podocyte slit diaphragm-associated proteins in nephrotic patients with NPHS2 mutation

In vivo expression of podocyte slit diaphragm-associated proteins in nephrotic patients with NPHS2 mutation.BackgroundMutations in NPHS2, encoding podocin, are a prevalent cause of autosomal-recessive steroid-resistant nephrotic syndrome (SRNS). Podocin is a protein associated with the slit diaphragm that interacts with nephrin and CD2-associated protein (CD2AP) within lipid rafts.MethodsUsing renal biopsies of six patients, we analyzed the in vivo consequences of different types of NPHS2 mutations on (1) the podocyte expression and distribution of podocin using in situ hybridization and immunohistology and (2) the distribution of related podocyte proteins and glomerular extracellular matrix components.ResultsIn two patients with homozygous 855_856delAA or 419delG mutation, absence of podocyte labeling with the antibodies against the C-terminal domain contrasted with the normal expression of the N-terminal domain of the protein along the glomerular basement membrane (GBM). In patients carrying compound heterozygous mutations or variants (R168S/467_468insT, R138Q/V180M, and R291W/R229Q), or single heterozygous 976_977insA, podocin transcription appeared unchanged but the distribution of the protein was modified. Podocin was restricted to the podocyte body in the patient carrying the R168S/467_468insT mutation whereas strong immunolabeling of the podocyte body was associated with discrete labeling along the GBM in the three others. In all cases, podocin defect was associated with changes in the distribution of nephrin, CD2AP, and α-actinin: the proteins were mainly detected in the podocyte body, with mild expression along the GBM. There were no detectable changes in the distribution of other podocyte proteins or glomerular extracellular matrix components.ConclusionNPHS2 mutations result in profound alteration of podocin expression and/or distribution. Secondary changes in the distribution of nephrin, CD2AP, and α-actinin are additional evidences for the scaffolding role of podocin in the organization of the slit diaphragm