Binding of Estrogenic Compounds to Recombinant Estrogen Receptor-α: Application to Environmental Analysis

Estrogenic activity in environmental samples could be mediated through a wide variety of compounds and by various mechanisms. High-affinity compounds for estrogen receptors (ERs), such as natural or synthetic estrogens, as well as low-affinity compounds such as alkylphenols, phthalates, and polychlorinated biphenyls are present in water and sediment samples. Furthermore, compounds such as polycyclic aromatic hydrocarbons, which do not bind ERs, modulate estrogen activity by means of the aryl hydrocarbon receptor (AhR). In order to characterize compounds that mediate estrogenic activity in river water and sediment samples, we developed a tool based on the ER-αligand-binding domain, which permitted us to estimate contaminating estrogenic compound affinities. We designed a simple transactivation assay in which compounds of high affinity were captured by limited amounts of recombinant ER-αand whose capture led to a selective inhibition of transactivation. This approach allowed us to bring to light that water samples contain estrogenic compounds that display a high affinity for ERs but are present at low concentrations. In sediment samples, on the contrary, we showed that estrogenic compounds possess a low affinity and are present at high concentration. Finally, we used immobilized recombinant ER-αto separate ligands for ER and AhR that are present in river sediments. Immobilized ER-α, which does not retain dioxin-like compounds, enabled us to isolate and concentrate ER ligands to facilitate their further analysis

Variable Nav1.5 Protein Expression from the Wild-Type Allele Correlates with the Penetrance of Cardiac Conduction Disease in the Scn5a+/− Mouse Model

BACKGROUND: Loss-of-function mutations in SCN5A, the gene encoding Na(v)1.5 Na+ channel, are associated with inherited cardiac conduction defects and Brugada syndrome, which both exhibit variable phenotypic penetrance of conduction defects. We investigated the mechanisms of this heterogeneity in a mouse model with heterozygous targeted disruption of Scn5a (Scn5a(+/-) mice) and compared our results to those obtained in patients with loss-of-function mutations in SCN5A. METHODOLOGY/PRINCIPAL FINDINGS: Based on ECG, 10-week-old Scn5a(+/-) mice were divided into 2 subgroups, one displaying severe ventricular conduction defects (QRS interval>18 ms) and one a mild phenotype (QRS53 weeks), ajmaline effect was larger in the severely affected subgroup. These data matched the clinical observations on patients with SCN5A loss-of-function mutations with either severe or mild conduction defects. Ventricular tachycardia developed in 5/10 old severely affected Scn5a(+/-) mice but not in mildly affected ones. Correspondingly, symptomatic SCN5A-mutated Brugada patients had more severe conduction defects than asymptomatic patients. Old severely affected Scn5a(+/-) mice but not mildly affected ones showed extensive cardiac fibrosis. Mildly affected Scn5a(+/-) mice had similar Na(v)1.5 mRNA but higher Na(v)1.5 protein expression, and moderately larger I(Na) current than severely affected Scn5a(+/-) mice. As a consequence, action potential upstroke velocity was more decreased in severely affected Scn5a(+/-) mice than in mildly affected ones. CONCLUSIONS: Scn5a(+/-) mice show similar phenotypic heterogeneity as SCN5A-mutated patients. In Scn5a(+/-) mice, phenotype severity correlates with wild-type Na(v)1.5 protein expression

Canalopathies cardiaques et modèles murins

Les "canalopathies" cardiaques sont des maladies d'origine congénitale ou acquise associées à des dysfonctionnements des canaux ioniques. Cette thèse est consacrée à l'étude de deux modèles transgéniques murins. L'intérêt de la transgenèse réside dans le fait que l'expression et la fonction des gènes peuvent être étudiées in vivo. Le premier modèle consiste en la sur-expression du canal humain HERG au niveau cardiaque chez !a souris. L'étude de ce modèle a pour la première fois mis en évidence que l'expression de canal HERG a des effets antiarythmiques in vivo. Le second est l'étude de souris invalidées pour le gène Scn5a. Ces souris hétérozygotes présentent une réduction de 50% de leur courant sodique et des troubles de conduction, s'aggravant avec l'âge, associés à un processus scléreux dégénératif. Ce modèle murin présente toutes les caractéristiques phénotypiques de la maladie de Lenègre.Cardiac channelopathies are inherited or acquired diseases linked to ionic channel dysfonction. This thesis is about two transgenic murine models. The interest of transgenese is that gene expression and function can be study in vivo. The first murine model overexpresses the human HERG channel in the mouse heart. Its study has shown for the first time antiarrhythmic effects of HERG expression in vivo. The second murine model is a knock-out of Scn5a gene. Heterozygous mice have a 50 % reduction in their cardiac myocytes Na+ current and exhibit cardiac conduction defects. These cardiac conduction defects worsen with age and are associated with fibrosis. Scn5a +/- mice are a convincing model for Lenègre's disease.NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Pour une sémiologie du cinéma (aspects théoriques et méthodologiques)

PARIS5-BU Saints-Pères (751062109) / SudocPARIS4-CELSA (920512201) / SudocSudocFranceF

Boosting syntax training with temporally regular musical primes in children with cochlear implants

International audienceObjectives : Previous research has suggested the use of rhythmic structures (implemented in musical material) to improve linguistic structure processing (i.e., syntax processing), in particular for populations showing deficits in syntax and temporal processing (e.g., children with developmental language disorders). The present study proposes a long-term training program to improve syntax processing in children with cochlear implants, a population showing syntax processing deficits in perception and production.Methods : The training program consisted of morphosyntactic training exercises (based on speech processing) that were primed by musical regular primes (8 sessions) or neutral baseline primes (environmental sounds) (8 sessions). A crossover design was used to train 10 deaf children with cochlear implants. Performance in grammatical processing, non-word repetition, attention and memory was assessed before and after training.Results : Training increased performance for syntax comprehension after both prime types but for grammaticality judgements and non-word repetition only when musical primes were used during training. For the far-transfer tests, some effects were also observed for attention tasks, especially if fast and precise sequential analysis (sequencing) was required, but not for memory tasks.Conclusions : The findings extend the previously observed beneficial short-term effects of regular musical primes in the laboratory to long-term training effects. Results suggest that the musical primes improved the processing of the syntactic training material, thus enhancing the training effects on grammatical processing as well as phonological processing and sequencing of speech signals. The findings can be interpreted within the dynamic attending theory (postulating the modulation of attention over time) and associated oscillatory brain activity. Furthermore, the findings encourage the use of rhythmic structures (even in non-verbal materials) in language training programs and outline perspectives for rehabilitation

Localization of Cyclins K and L in interphase.

<p>GFP-cyclin K and HA-cyclins L1 and L2 were expressed in HeLa cells and their localizations were analysed by fluorescence microscopy using respectively GFP-cyclin K (A) or immunofluorescence with anti-cyclin L1 (D) and L2 (G) antibodies. Localizations were compared with the one of endogenous PTB (B,E,H). Respective merge images (C,F,I) show an absence or a very poor co-localization of cyclins with CDK13 in PNC. An increased magnification of merge labelling is inserted in C and I. Scale bar: 5μm.</p