Biological diversity and the possible involvement of aquatic Hemiptera in the transmission of Mycobacterium ulcerans, an etiological agent of Buruli ulcer in Côte d’Ivoire (West Africa)

International audienc

Was Phanerozoic reef history controlled by the distribution of non-enzymatically secreted reef carbonates (microbial carbonate and biologically induced cement)?

Throughout most of the Phanerozoic, reef rigidity resulted as much, or more, from early lithification by microbial carbonates and biologically induced cements (non-enzymatic carbonates) than from biological encrustation of, or by, large, enzymatically secreted metazoan skeletons. Reef framework is divided into four categories: (1) skeletal metazoan; (2) non-skeletal microbialite (stromatolite and thrombolite); (3) calcimicrobe; and (4) biocementstone, in which small or delicate organisms serve as scaffolds for rigid cement crusts. The last three categories are dominated by non-enzymatic carbonates. Skeletal framework and non-skeletal microbialite framework were the most abundant framework types through the Phanerozoic. The composition and abundance of skeletal framework was controlled largely by mass extinction events, but most reefs consisted of both microbialite and skeletal organisms in a mutually beneficial relationship. Microbialite framework was abundant throughout the Palaeozoic and early Mesozoic, but declined after the Jurassic. Calcimicrobe framework was important during the Cambrian-Early Ordovician and Devonian and biocementstone framework was important from the late Mississippian to the Late Triassic. The Phanerozoic history of reefs does not correlate well with the stratigraphic distribution of large, skeletal 'reef builders', or with a variety of physicochemical parameters, including sea-level history, Wilson Cycle or global climate cycles. Because non-enzymatic carbonates result from induction by non-obligate calcifiers, and not enzymatic precipitation by obligate calcifiers, the distribution of these carbonates was controlled to a larger extent by temporal changes in physicochemical parameters affecting the saturation state of sea water with respect to carbonate minerals. Changes in pCO, Ca/Mg ratios, cation concentrations and temperature may have affected the abundance of non-enzymatic carbonates and, hence, reefs, independently from the effects of these same parameters and mass extinction events on skeletal reef biota. The decline in abundance of reefal microbialite and absence of calcimicrobe and biocementstone reef framework after the Jurassic may be a result of relatively low saturation states of sea water owing to increased removal and sequestration of finite marine carbonate resources by calcareous plankton since the Jurassic. Reef history is difficult to correlate with temporal changes in specific global parameters because these parameters affect skeletal biota and biologically induced carbonate precipitation independently. Hence, reef history was regulated not just by skeletal reef biota, but by parameters governing non-enzymatic carbonates

Common Genetic Variation and Age of Onset of Anorexia Nervosa.

Genetics and biology may influence the age of onset of anorexia nervosa (AN). The aims of this study were to determine whether common genetic variation contributes to age of onset of AN and to investigate the genetic associations between age of onset of AN and age at menarche. A secondary analysis of the Psychiatric Genomics Consortium genome-wide association study (GWAS) of AN was performed, which included 9335 cases and 31,981 screened controls, all from European ancestries. We conducted GWASs of age of onset, early-onset AN (<13 years), and typical-onset AN, and genetic correlation, genetic risk score, and Mendelian randomization analyses. Two loci were genome-wide significant in the typical-onset AN GWAS. Heritability estimates (single nucleotide polymorphism-h <sup>2</sup> ) were 0.01-0.04 for age of onset, 0.16-0.25 for early-onset AN, and 0.17-0.25 for typical-onset AN. Early- and typical-onset AN showed distinct genetic correlation patterns with putative risk factors for AN. Specifically, early-onset AN was significantly genetically correlated with younger age at menarche, and typical-onset AN was significantly negatively genetically correlated with anthropometric traits. Genetic risk scores for age of onset and early-onset AN estimated from independent GWASs significantly predicted age of onset. Mendelian randomization analysis suggested a causal link between younger age at menarche and early-onset AN. Our results provide evidence consistent with a common variant genetic basis for age of onset and implicate biological pathways regulating menarche and reproduction

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

International audienceBackground: Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation. Methods: WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109. Findings: Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0–4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2–6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital. Interpretation: In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates. Funding: European Society of Intensive Care Medicine, European Respiratory Society