Development and evaluation of a method to identify potential release areas of snow avalanches based on watershed delineation

Snow avalanches are a prevalent threat in mountain territories. Large-scale mapping of avalanche-prone terrain is a prerequisite for land-use planning where historical information about past events is insufficient. To this aim, the most common approach is the identification of potential release areas (PRAs) followed by numerical avalanche simulations. Existing methods for identifying PRAs rely on terrain analysis. Despite their efficiency, they suffer from (i) a lack of systematic evaluation on the basis of adapted metrics and past observations over large areas and (ii) a limited ability to distinguish PRAs corresponding to individual avalanche paths. The latter may preclude performing numerical simulations corresponding to individual avalanche events, questioning the realism of resulting hazard assessments. In this paper, a method that accurately identifies individual snow avalanche PRAs based on terrain parameters and watershed delineation is developed, and confusion matrices and different scores are proposed to evaluate it. Comparison to an extensive cadastre of past avalanche limits from different massifs of the French Alps used as ground truth leads to true positive rates (recall) between 80 % and 87 % in PRA numbers and between 92.4 % and 94 % in PRA areas, which shows the applicability of the method to the French Alps context. A parametric study is performed, highlighting the overall robustness of the approach and the most important steps/choices to maximize PRA detection, among which the important role of watershed delineation to identify the right number of individual PRAs is highlighted. These results may contribute to better understanding avalanche hazard in the French Alps. Wider outcomes include an in-depth investigation of the issue of evaluating automated PRA detection methods and a large data set that could be used for additional developments, and to benchmark existing and/or new PRA detection methods.</p

Induction du travail par misoprostol oral versus misoprostol vaginal : étude avant-après

International audienceObjective: The rate of induction of labor represented 22 % of deliveries in 2016 in France. Oral misoprostol (Angusta®) was marketed in France in the last quarter of 2018. The objective of our study was to compare the efficacy and safety of induction of labor with oral misoprostol compared to vaginal misoprostol in women with an unripe cervix. Material and methods: We carried out a retrospective study before and after the implementation of oral misoprostol including all women with an unripe cervix who benefited from an induction of labor with a viable infant in vertex presentation, without uterine scar. During the first two-year period, women received 50 μg of misoprostol in the posterior fornix, repeated 6 hours later if needed. If labor had not started after 24 hours, women received another dose of 50 μg, which was repeated every 4 hours until labor was established, up to a total dose of 150 μg. During the second two-year period, women received two tablets of oral misoprostol 25 μg every four hours if necessary, up to a total dose of 200 μg. The primary endpoints were mode of delivery and neonatal safety. Results: During the two study periods, 1199 women received vaginal misoprostol and 1199 women received oral misoprostol including. The cesarean delivery rate was 21.8% during the first period and 21,3% during the second period (P = 0.83). A 5-minutes Apgar score < 7 was observed in 23 (1.9%) and 14 (1.2%) newborns in the vaginal misoprostol and oral misoprostol groups (P = 0.14), respectively. An arterial cord pH < 7.00 was observed in 6 (0.5%) and 7 (0.6%) newborns (P = 0.99), respectively. Conclusion: Oral misoprostol administered at the dose of 50 μg every 4 hours (up to a total dose of 200 μg) is as effective and safe as the vaginal misoprostol to induce labor in women with an unripe cervix

Is gestational age at term a risk factor for ongoing pregnancies in nulliparous women: A prospective cohort study

International audienceBACKGROUND: The results of American observational studies and 1 large, randomized trial show that elective induction of labor among nulliparous women can reduce cesarean delivery rates and suggest that gestational age at delivery may be a risk factor for cesarean delivery in pregnancies managed expectantly. However, data on the risk of cesarean delivery at term in ongoing pregnancies are sparse, especially in high-income countries, and further information is needed to explore the external validity of these previous studies. OBJECTIVE: This study aimed to evaluate the risk of cesarean delivery for each gestational week of ongoing pregnancy in nulliparous women with a singleton fetus in the cephalic presentation at term in a French population. STUDY DESIGN: This retrospective study was conducted in a perinatal network of 10 maternity units from January 1, 2016, to December 31, 2017, and included all nulliparous women with a singleton fetus in the cephalic presentation who gave birth at term (≥37 0/7 weeks of gestation). From the start of term (37 completed weeks) and at the start of each subsequent week of completed gestation (each week + 0 days), ongoing pregnancy was defined as that of a woman who was still pregnant and who gave birth at any time after that date. For each week of gestation for these ongoing pregnancies, the cesarean delivery rate was defined as the number of cesarean deliveries performed in each ongoing pregnancy group divided by the number of women in this group. Separate models for each week of gestation, adjusted by maternal characteristics and hospital status, were used to compare the cesarean delivery risk between ongoing pregnancies and those delivered the preceding week. The same methods were applied to subgroups defined according to the mode of labor onset. Odds ratios were calculated after adjusting for maternal age and educational level, presence of severe preeclampsia, and maternity unit status. RESULTS: The study included 11,308 nulliparous women, 2544 (22.5%) of whom had a cesarean delivery. These rates remained stable for ongoing pregnancies at 37 0/7, 38 0/7, and 39 0/7 weeks of gestation; the rates were 22.5% (95% confidence interval, 21.7–23.2), 22.6% (95% confidence interval, 21.8–23.3); and 22.7% (95% confidence interval, 21.9–23.6), respectively. The risk of cesarean delivery started to increase in ongoing pregnancies at 40 0/7 weeks of gestation (24.3%; 95% confidence interval, 23.1–25.4) and especially at 41 0/7 weeks of gestation (30.7%; 95% confidence interval, 28.9–32.5). Similar trends were also shown for all modes of labor onset and in every maternity unit. In univariate and multivariate analyses, ongoing pregnancy at or beyond 40 0/7 weeks of gestation was associated with a higher risk of cesarean delivery than pregnancy delivered the previous week: 24.3% of ongoing pregnancies at 40 0/7 weeks of gestation vs 19.9% of deliveries between 39 0/7 weeks of gestation and 39 6/7 weeks of gestation. The odds ratios were 1.28 (95% confidence interval, 1.15–1.44) or 30.4% of ongoing pregnancies at 41 0/7 weeks of gestation vs 1.73 (95% confidence interval, 1.51–1.96) or 19.6% of deliveries between 40 0/7 weeks of gestation and 40 6/7 weeks of gestation. CONCLUSION: Cesarean delivery rates increased starting at 40 0/7 weeks of gestation in ongoing pregnancies regardless of the mode of labor onset

L'ADN fœtal libre circulant : un outil d’évaluation du risque de survenue de complications obstétricales ?

International audienceObjective: The aim of the study was to evaluate if fetal cell-free DNA (cfDNA) fraction circulating in maternal blood at the beginning of the second trimester is associated with obstetrical complications. Methods: This is a retrospective unicentric study conducted at the hospital of Poissy Saint Germain between the 1st January 2015, and the 31st. December 2016, Each woman who had a genetic counseling in order to realize a non-invasive prenatal test (NIPT) was included. Only singleton pregnancies with a documented-issue were analysed. The primary criteria was a composite criteria, defined as the occurrence of preeclampsia, in utero fetal growth, or a spontaneous preterm delivery. A descriptive analyse was first conducted, secondly completed by a sub-group one: “high fetal fraction” (&gt; 90th percentile) group, “low fetal-fraction” group (&lt; 10th percentile) and “medium fetal-fraction” (control group) group. Results: A total of 417 women had a cfDNA test, which was performed at a mean gestational age of 17.1 weeks of gestation. A total of 17% of pregnancies met the primary criteria. Among them, there were 8 (1.9%) pre-eclampsia, 49 (11.8%) intra-uterine growth restriction and 14 (3.4%) preterm births. There was no significant difference for the occurrence of the primary criteria (P &gt; 0.99) and of each obstetrical complication between each group. Conclusion: Fetal cf-DNA fraction measured at the beginning of the second trimester is not associated with common obstetrical complications

The variant surface glycoproteins of Trypanosoma equiperdum Identification of a phosphorylated glycopeptide as the cross-reacting antigenic determinant

AbstractThe cross-reacting antigenic determinant in the variant surface glycoproteins (VSGs) of Trypanosoma equiperdum was studied by testing the ability of VSG glycopeptides to bind heterologous anti-VSG sera. VSG glycopeptide purification revealed the presence of 3 oligosaccharide sidechains on the mature VSG. These consist of two sidechains containing only mannose and glucosamine and a third containing galactose and mannose (in a 5 : 1 ratio) as well as phosphorous and ethanolamine. This phosphorylated fragment completely blocked the binding of VSG to heterologous anti-VSG and therefore contained the cross-reacting determinants

Physical and immunological analysis of the two domains isolated from a variant surface glycoprotein of Trypanosoma brucei.

A specific surface glycoprotein of a variant of Trypanosoma brucei was cleaved with trypsin and the two major domains of the molecule have been purified. We have studied the chemical composition of each domain and compared the data to published results of the specific cDNA sequence. Circular dichroism measurements show that the amino-terminal domain includes preferentially alpha-helical or beta-sheet structure. The physicochemical analyses are supplemented by a prediction of secondary structure and a statistical pattern of hydrophilicity-hydrophobicity. The results are discussed in light of the internal limits that were described in the process of partial gene conversion occurring between the variant gene sequence and related members of the same gene family. Immunoblots with homologous antiserum indicate that the amino-terminal domain is implicated in antigenicity. In addition, immunoblotting with heterologous antiserum on native antigen, tryptic hydrolysates, or purified domains suggests a site of interaction supported by the two domains.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Trypanosoma brucei: the extent of conversion in antigen genes may be related to the DNA coding specificity.

The boundaries of gene conversion in variant-specific antigen genes have been determined in six clones of Trypanosoma brucei. In each clone, antigenic switching involved interaction between two telomeric members of the AnTat 1.1 multigene family, which share extensive homology throughout their coding regions. All conversion events occurred by substitution of faithful copies of donor sequences. Conversion endpoints were nonrandomly distributed. In four clones, the 5' conversion limit was near the antigen translation initiation codon, while in three clones, the 3' conversion limit was located at the "hinge" between the two major antigen domains. In one case, two segmental conversions were involved in antigen switching. These observations reveal that antigen gene conversion can occur without generating point mutations, and suggest that postrecombinational selection may impose a limit on the number of possible rearrangements within antigen genes.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe