Phylogeographic pattern of range expansion provides evidence for cryptic species lineages in Silene nutans in Western Europe.

As a result of recent or past evolutionary processes, a single species might consist of distinct Evolutionary Significant Units (ESUs), even corresponding to cryptic species. Determining the underlying mechanisms of range shifts and the processes at work in the build-up of divergent ESUs requires elucidating the factors that contribute to population genetic divergence across a species' range. We investigated the large-scale patterns of genetic structure in the perennial herbaceous plant species Silene nutans (Caryophyllaceae) in Western Europe. We sampled and genotyped 111 populations using 13 nuclear microsatellite loci and 6 plastid single-nucleotide polymorphisms. Broad-scale spatial population genetic structure was examined using Bayesian clustering, spatial multivariate analyses and measures of hierarchical genetic differentiation. The genotypic structure of S. nutans was typical of a predominantly allogamous mating system. We also identified plastid lineages with no intra-population polymorphism, mirroring two genetically differentiated nuclear lineages. No evidence of admixture was found. Spatial trends in genetic diversity further suggested independent leading-edge expansion associated with founding events and subsequent genetic erosion. Overall, our findings suggested speciation processes in S. nutans and highlighted striking patterns of distinct stepwise recolonisation of Western Europe shaped by Quaternary climate oscillations. Two main potential ESUs can be defined in Western Europe, corresponding to Eastern and Western nuclear-plastid lineages. In situ preservation of populations and genetic rescue implying ex situ conservation techniques should take the lineage identity into account. This is particularly true in Great Britain, northern France and Belgium, where S. nutans is rare and where distinct lineages co-occur in close contact.

[The emergency department: an appropriate place for identifying troubled teens]. / Les urgences, un lieu de repérage des adolescents en difficulté

OBJECTIVES: The main objective of this study was to estimate the prevalence of psychological distress among adolescents seen in emergency departments, and the secondary objective was to highlight their main reasons for consulting. METHODS: Cross-sectional study in three multicenter emergency departments receiving adolescents in Île-de-France conducted in 2010. All adolescents completed a questionnaire including the ADRS (Adolescent Depression Rating Scale, a screening questionnaire for depression) and a series of questions relating to somatization and risk behaviors. RESULTS: The study included 346 adolescents, 320 of which were fully analyzed. The ADRS score was considered normal (score < 3) for 70.6% of the sample (n = 226), 19.4% of adolescents (n = 62) had moderate depressive symptoms (3 ≤ score < 6), and 10.0% severe depressive symptoms (score ≥ 6) (n = 32). The majority of patients consulted for trauma and less than 10% for acute psychiatric problems; 17% of adolescents who came to the emergency department for a nonpsychiatric reason had an ADRS ≥ 3, i.e., with mental distress. CONCLUSION: The routine use of a self-administered questionnaire in the emergency services could identify adolescents with moderate to severe depressive symptoms.

[Juvenile osteoporosis]. / Les ostéoporoses juvéniles.

Osteoporosis is induced by a disorder of the bone turnover that generates an accelerated destruction process and leads to the rarefaction of the protein matrix. The RANK-L/RANK/OPG system is the main actor of the bone remodelling regulation. Juvenile osteoporoses may have primary or secondary aetiologies. The main causes include constitutional bone fragilities, and osteoporoses, which are secondary to chronic inflammatory diseases and sustained steroid treatment. Etiologic diagnosis relies on a clinical basis, and is often made too lately when complications occur. Osteodensitometry is a sensitive and noninvasive tool for measuring mineral bone density in children. The reliability of results is limited by the variations due to patients' age, gender, pubertal stage, and by the length of bone pieces. The optimal treatment of osteoporosis is preventive, and includes accurate nutritional diet, D vitamin-calcium supplementation and regular physical activity. Biphosphonates are used for treatment of symptomatic osteoporoses. Careful utilization is required in childhood because their late potential secondary effects are still unknown. New antiresorptive drugs and other that stimulate osteoformation are successfully used in adults. Their effects have not been studied in the paediatric population.