Counteraction of Tetherin Antiviral Activity by Two Closely Related SIVs Differing by the Presence of a Vpu Gene

In different primate lentiviruses, three proteins (Vpu, Env and Nef) have been shown to have anti-tetherin activities. SIVden is a primate lentivirus harbored by a Cercopithecus denti (C. denti) whose genome code for a Vpu gene. We have compared the activity of HIV-1 Vpu and of SIVden Vpu on tetherin proteins from humans, from C. denti and from Cercopithecus neglectus (C. neglectus), a monkey species that is naturally infected by SIVdeb, a virus closely related to SIVden but which does not encode a Vpu protein. Here, we demonstrate that SIVden Vpu, is active against C. denti tetherin, but not against human tetherin. Interestingly, C. neglectus tetherin was more sensitive to SIVden Vpu than to HIV-1 Vpu. We also identify residues in the tetherin transmembrane domains that are responsible for the species-specific Vpu effect. Simultaneous mutation (P40L and T45I) of human tetherin conferred sensitivity to SIVden Vpu, while abolishing its sensitivity to HIV-1 Vpu. We next analyzed the anti-tetherin activity of the Nef proteins from HIV-1, SIVden and SIVdeb. All three Nef proteins were unable to rescue virus release in the presence of human or C. denti tetherin. Conversely, SIVdeb Nef enhanced virus release in the presence of C. neglectus tetherin, suggesting that SIVdeb relies on Nef in its natural host. Finally, while HIV-1 Vpu not only removed human tetherin from the cell surface but also directed it for degradation, SIVden Vpu only induced the redistribution of both C. denti and C. neglectus tetherins, resulting in a predominantly perinuclear localization

Hémorragie du post-partum : recommandations pour la pratique clinique — Texte des recommandations (texte court)

International audienc

Survival and Morbidity of Preterm Children Born at 22 Through 34 Weeks’ Gestation in France in 2011

International audienceImportance Up-to-date estimates of the health outcomes of preterm children are needed for assessing perinatal care, informing parents, making decisions about care, and providing evidence for clinical guidelines. Objectives To determine survival and neonatal morbidity of infants born from 22 through 34 completed weeks’ gestation in France in 2011 and compare these outcomes with a comparable cohort in 1997. Design, Setting, and Participants The EPIPAGE-2 study is a national, prospective, population-based cohort study conducted in all maternity and neonatal units in France in 2011. A total of 2205 births (stillbirths and live births) and terminations of pregnancy at 22 through 26 weeks’ gestation, 3257 at 27 through 31 weeks, and 1234 at 32 through 34 weeks were studied. Cohort data were collected from January 1 through December 31, 1997, and from March 28 through December 31, 2011. Analyses for 1997 were run for the entire year and then separately for April to December; the rates for survival and morbidities did not differ. Data are therefore presented for the whole year in 1997 and the 8-month and 6-month periods in 2011. Main Outcomes and Measures Survival to discharge and survival without any of the following adverse outcomes: grade III or IV intraventricular hemorrhage, cystic periventricular leukomalacia, severe bronchopulmonary dysplasia, retinopathy of prematurity (stage 3 or higher), or necrotizing enterocolitis (stages 2-3). Results A total of 0.7% of infants born before 24 weeks’ gestation survived to discharge: 31.2% of those born at 24 weeks, 59.1% at 25 weeks, and 75.3% at 26 weeks. Survival rates were 93.6% at 27 through 31 weeks and 98.9% at 32 through 34 weeks. Infants discharged home without severe neonatal morbidity represented 0% at 23 weeks, 11.6% at 24 weeks, 30.0% at 25 weeks, 47.5% at 26 weeks, 81.3% at 27 through 31 weeks, and 96.8% at 32 through 34 weeks. Compared with 1997, the proportion of infants surviving without severe morbidity in 2011 increased by 14.4% (P < .001) at 25 through 29 weeks and 6% (P < .001) at 30 through 31 weeks but did not change appreciably for those born at less than 25 weeks. The rates of antenatal corticosteroid use, induced preterm deliveries, cesarean deliveries, and surfactant use increased significantly in all gestational-age groups, except at 22 through 23 weeks. Conclusions and Relevance The substantial improvement in survival in France for newborns born at 25 through 31 weeks’ gestation was accompanied by an important reduction in severe morbidity, but survival remained rare before 25 weeks. Although improvement in survival at extremely low gestational age may be possible, its effect on long-term outcomes requires further studies. The long-term results of the EPIPAGE-2 study will be informative in this regard

Antibiotic prophylaxis in preterm premature rupture of membranes at 24–31 weeks’ gestation: Perinatal and 2‐year outcomes in the EPIPAGE‐2 cohort

International audienceObjectiveTo compare different antibiotic prophylaxis administered after preterm premature rupture of membranes to determine whether any were associated with differences in obstetric and/or neonatal outcomes and/or neurodevelopmental outcomes at 2 years of corrected age.DesignProspective, nationwide, population-based EPIPAGE-2 cohort study of preterm infants.SettingFrance, 2011.SampleWe included 492 women with a singleton pregnancy and a diagnosis of preterm premature rupture of membranes at 24–31 weeks. Exclusion criteria were contraindication to expectant management or indication for antibiotic therapy other than preterm premature rupture of membranes. Antibiotic prophylaxis was categorised as amoxicillin (n = 345), macrolide (n = 30), third-generation cephalosporin (n = 45) or any combinations covering Streptococcus agalactiae and >90% of Escherichia coli (n = 72), initiated within 24 hours after preterm premature rupture of membranes.MethodsPopulation-averaged robust Poisson models.Main Outcome MeasuresSurvival at discharge without severe neonatal morbidity, 2-year neurodevelopment.ResultsWith amoxicillin, macrolide, third-generation cephalosporin and combinations, 78.5%, 83.9%, 93.6% and 86.0% of neonates were discharged alive without severe morbidity. The administration of third-generation cephalosporin or any E. coli-targeting combinations was associated with improved survival without severe morbidity (adjusted risk ratio 1.25 [95% confidence interval 1.08–1.45] and 1.10 [95 % confidence interval 1.01–1.20], respectively) compared with amoxicillin. We evidenced no increase in neonatal sepsis related to third-generation cephalosporin-resistant pathogen.ConclusionIn preterm premature rupture of membranes at 24–31 weeks, antibiotic prophylaxis based on third-generation cephalosporin may be associated with improved survival without severe neonatal morbidity when compared with amoxicillin, with no evidence of increase in neonatal sepsis related to third-generation cephalosporin-resistant pathogen