Epigenetic status of H19/IGF2 and SNRPN imprinted genes in aborted and successfully derived embryonic stem cell lines in non-human primates

AbstractThe imprinted genes of primate embryonic stem cells (ESCs) often show altered DNA methylation. It is unknown whether these alterations emerge while deriving the ESCs. Here we studied the methylation patterns of two differentially methylated regions (DMRs), SNRPN and H19/IGF2 DMRs, during the derivation of monkey ESCs. We show that the SNRPN DMR is characteristically methylated at maternal alleles, whereas the H19/IGF2 DMR is globally highly methylated, with unusual methylation on the maternal alleles. These methylation patterns remain stable from the early stages of ESC derivation to late passages of monkey ESCs and following differentiation. Importantly, the methylation status of H19/IGF2 DMR and the expression levels of IGF2, H19, and DNMT3B mRNAs in early embryo-derived cells were correlated with their capacity to generate genuine ESC lines. Thus, we propose that these markers could be useful to predict the outcomes of establishing an ESC line in primates

Respiratory pulse pressure variation fails to predict fluid responsiveness in acute respiratory distress syndrome

International audienceIntroduction: Fluid responsiveness prediction is of utmost interest during acute respiratory distress syndrome (ARDS), but the performance of respiratory pulse pressure variation (Δ RESP PP) has scarcely been reported. In patients with ARDS, the pathophysiology of Δ RESP PP may differ from that of healthy lungs because of low tidal volume (Vt), high respiratory rate, decreased lung and sometimes chest wall compliance, which increase alveolar and/or pleural pressure. We aimed to assess Δ RESP PP in a large ARDS population. Methods: Our study population of nonarrhythmic ARDS patients without inspiratory effort were considered responders if their cardiac output increased by >10% after 500-ml volume expansion. Results: Among the 65 included patients (26 responders), the area under the receiver-operating curve (AUC) for Δ RESP PP was 0.75 (95% confidence interval (CI 95): 0.62 to 0.85), and a best cutoff of 5% yielded positive and negative likelihood ratios of 4.8 (CI 95 : 3.6 to 6.2) and 0.32 (CI 95 : 0.1 to 0.8), respectively. Adjusting Δ RESP PP for Vt, airway driving pressure or respiratory variations in pulmonary artery occlusion pressure (ΔPAOP), a surrogate for pleural pressure variations, in 33 Swan-Ganz catheter carriers did not markedly improve its predictive performance. In patients with ΔPAOP above its median value (4 mmHg), AUC for Δ RESP PP was 1 (CI 95 : 0.73 to 1) as compared with 0.79 (CI 95 : 0.52 to 0.94) otherwise (P = 0.07). A 300-ml volume expansion induced a ≥2 mmHg increase of central venous pressure, suggesting a change in cardiac preload, in 40 patients, but none of the 28 of 40 nonresponders responded to an additional 200-ml volume expansion. Conclusions: During protective mechanical ventilation for early ARDS, partly because of insufficient changes in pleural pressure, Δ RESP PP performance was poor. Careful fluid challenges may be a safe alternative

Qu'est-ce que l'assurance ?

Lefèvre Annick. Qu'est-ce que l'assurance ?. In: Diplômées, n°219, 2006. L'assurance et les femmes. pp. 206-209

Structural and dynamic characterization of omega-conotoxin MVIIA: the binding loop exhibits slow conformational exchange

omega-Conotoxin MVIIA is a 25-residue, disulfide-bridged polypeptide from the venom of the sea snail Conus magus that binds to neuronal N-type calcium channels. It forms a compact folded structure, presenting a loop between Cys8 and Cys15 that contains a set of residues critical for its binding. The loop does not have a unique defined structure, nor is it intrinsically flexible. Broadening of a subset of resonances in the NMR spectrum at low temperature, anomalous temperature dependence of the chemical shifts of some resonances, and exchange contributions to J(0) from (13)C relaxation measurements reveal that conformational exchange affects the residues in this loop. The effects of this exchange on the calculated structure of omega-conotoxin MVIIA are discussed. The exchange appears to be associated with a change in the conformation of the disulfide bridge Cys8-Cys20. The implications for the use of the omega-conotoxins as a scaffold for carrying other functions is discussed

Follicular growth in vitro: Detection of growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) during in vitro culture of ovine cortical slices

International audiencePrimordial follicles from different mammal species can survive and enter the growth phase in vitro but do not develop beyond the primary stage. The hypothesis was that, in sheep, in vitro follicular growth is arrested because of a lack of secretion of GDF9 and/or BMP15. Cortical slices of 0.3-0.5 mm thickness issued from 5- to 6-month-old lambs were cultured for 15 days. The pieces were fixed on days 0, 2, 4, 7, 10, and 15 of culture. Follicle morphology, RT-PCR exploration of GDF9 and BMP15 mRNA, immunolhistochemical location of their proteins and their receptor BMPRIB and BMPRII were assessed at different time of culture. The mean percentage of primordial follicles decreased from 58.6% (day 0) to 13.4% (day 15) (P < 0.01), whereas that of primary follicles increased from 3.2% (day 0) to 31.5% on day 4 (P < 0.01), then remained stable until day 15 (35.6%). The percentage of atretic follicles increased from 14.7% (day 0) to 27.1% (day 15) (P < 0.05). A few secondary follicles were observed on days 4 and 10, representing 1.0%, and 2.1% of the total number of follicles. GDF9 and BMP15 mRNAs were detected from harvesting (day 0) up to day 15 following culture. At the same time, positive immunoreactions for GDF9, BMP15 and for BMPRIB and BMPRII were also found in oocyte cytoplasm. In conclusion, expression of GDF9, BMP15 and their receptors BMPRIB and BMPRII are detected during in vitro culture of ovine cortical slices

Audit d'une nouvelle stratégie de prise en charge des hémorragies du post-partum: audit des hémorragies du post partum

International audienceLe but de ce travail était de réaliser un audit clinique des cas des hémorragies graves du post-partum en Basse-Normandie et d'en évaluer la prévalence avant et après la mise en place d'un protocole régional. En 2004, dans le cadre du réseau périnatal Bas-Normand, un protocole de prise en charge des hémorragies du post-partum a été diffusé dans l'ensemble des maternités. Une étude « avant-après » a été réalisée afin d'en mesurer l'impact : l'enquête SPHERE. Les hémorragies graves étaient définies par le recours à une transfusion sanguine, à une embolisation des artères utérines ou à une chirurgie d'hémostase, par un delta d'hémoglobine supérieur à 4g/dl ou par un décès maternel. Nous avons analysé les cas graves, sauf ceux définis par le delta d'hémoglobine, avant et après la mise en place du protocole. Les périodes d'étude étaient les années 2002 et 2005. L'audit a été réalisé par dix experts de la région (5 binômes, anesthésiste-réanimateur/gynécologue-obstétricien). Chaque dossier, attribué au hasard, a été évalué pour le suivi du protocole, pour la gravité de l'hémorragie et pour la qualité de la prise en charge. Le nombre d'hémorragies graves du post-partum est resté stable entre 2002 et 2005, respectivement 130 et 136 cas, ainsi que le nombre des naissances. Mais le nombre d'HPP sévères passées inaperçues est passé de 96 à 73. Le nombre d'HPP sévères auditées étaient de 34 cas en 2002 et de 63 en 2005. Le protocole était bien respecté dans l'ensemble de la région, la plupart des points audités étant suivis dans près de 90% des cas en 2005. Mais certaines pratiques ne sont pas encore systématiques, notamment la prise en charge active de la troisième phase du travail réalisée seulement dans 70,6% de cas. Les hémorragies étaient de gravité extrême dans 38,1% en 2005 contre 44,1% en 2002 (différence non statistiquement significative). La qualité de leur gestion a été améliorée, ainsi les prises en charge insuffisantes représentaient 12,7% en 2005 contre 32,3% en 2002 (p<0,020). L'originalité de ce travail réside dans le fait qu'il a été réalisé sur le plan médical à l'échelle d'un réseau de soins régional. Nous n'avons pas observé de diminution de la prévalence des hémorragies graves du post-partum en Basse-Normandie mais l'audit a montré que la qualité de la prise en charge avait progressé, certes encore insuffisamment. Seul le perfectionnement de nos pratiques favorisera la réduction du nombre d'hémorragies sévères du post-partum, une des solutions principales étant la formation médicale continue