Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Influence of the Colloidal Structure of Dairy Gels on Milk Fat Fusion Behavior: Quantification of the Liquid Fat Content by In Situ Quantitative Proton Nuclear Magnetic Resonance Spectroscopy (isq H-1 NMR)

Dairy gels (DG), such as yoghurts, contain both solid and liquid fats at the time of consumption, as their temperature rises to anything between 10 and 24 degrees C after being introduced into the mouth at 4 degrees C. The mass ratio between solid and liquid fats, which depends on the temperature, impacts the organoleptic properties of DG. As the ordinary methods for determining this ratio can only be applied to samples consisting mainly in fat materials, a fat extraction step needs to be added into the analytical process when applied to DG, which prevents the study of the potential impact of their colloidal structure on milk fat fusion behavior. In situ quantitative proton nuclear magnetic resonance spectroscopy (isq H-1 NMR) was investigated as a method for direct measurements in DG: at temperatures between 20.0 and 70.0 degrees C, the liquid fat content and the composition of triacylglycerols of the liquid phase (in terms of alkyl chains length) were determined. Spectra of isolated milk fat also enable the quantification of the double bonds of triacylglycerols. Statistical tests showed no significant difference between isolated milk fat and milk fat inside a DG in terms of melting behavior: the fat globule membrane does not seem to have a significant influence on the fat melting behavior

SPAD array sensitivity enhancement by diffractive microlens

International audienceIn this paper we present sensitivity improvement of SPAD pixel using diffractive microlens. We designed microlens structures based on rigorous optical simulations, then we developed the process for thick optical spacer and thin amorphous silicon deposition, on which diffractive structures were defined by lithography and etching. These microlenses have been implemented two SPAD designs available on STMicroelectronics 40nm CMOS testchips (32 × 32 SPAD array). Circuits were characterized and we demonstrated, depending on SPAD design, high optical gain at 850nm (×3 to ×8) and significant gain at 940nm (×2 to ×2.5)

Tn-seq library, a tool to decrypt Salmonella gene function

International audienceNumerous genomes are available in databases and one of the biggest challenges is to understand the function of each gene. In bacteria, transposon mutant libraries have long been used to identify genes important for bacterial survival, growth or virulence. Recent advances in high throughput sequencing now allow the screening of millions of mutants in a single or few experiments using methods such as TraDIS or Tn-seq. These methods are sensitive enough to detect small defects in mutant fitness and allow to study genes but also intergenic regions, promoter regions and essential protein domains in coding sequences if the library is saturated with transposon insertions. Here, we present the construction and the characterization of a saturated library in Salmonella Typhimurium ATCC 14028 virulent strain, which is commonly used in research laboratories. This library was obtained using the Himar1 transposon that randomly inserts into TA dinucleotides sites onto the genome. Transposon mutant library was sequenced with an Illumina NextSeq 500. After read mapping, further analyses were carried out with the TRANSIT software. These analyses confirmed saturation of the transposon mutant library both on the chromosome and the virulence plasmid. This allowed us to determine the essential genes and those providing advantage or disadvantage for bacterial growth. This Tn-seq library is now used in several research projects and is available to the scientific community through collaboratio

Tn-seq library, a tool to decrypt Salmonella gene function

International audienceNumerous genomes are available in databases and one of the biggest challenges is to understand the function of each gene. In bacteria, transposon mutant libraries have long been used to identify genes important for bacterial survival, growth or virulence. Recent advances in high throughput sequencing now allow the screening of millions of mutants in a single or few experiments using methods such as TraDIS or Tn-seq. These methods are sensitive enough to detect small defects in mutant fitness and allow to study genes but also intergenic regions, promoter regions and essential protein domains in coding sequences if the library is saturated with transposon insertions. Here, we present the construction and the characterization of a saturated library in Salmonella Typhimurium ATCC 14028 virulent strain, which is commonly used in research laboratories. This library was obtained using the Himar1 transposon that randomly inserts into TA dinucleotides sites onto the genome. Transposon mutant library was sequenced with an Illumina NextSeq 500. After read mapping, further analyses were carried out with the TRANSIT software. These analyses confirmed saturation of the transposon mutant library both on the chromosome and the virulence plasmid. This allowed us to determine the essential genes and those providing advantage or disadvantage for bacterial growth. This Tn-seq library is now used in several research projects and is available to the scientific community through collaboratio

Construction and characterization of saturated Tn-seq libraries for two serovars of Salmonella : Salmonella Typhimurium and Salmonella Enteritidis

International audienceNumerous genomes are available in databases and one of the biggest challenges is to understand the function of each gene. In bacteria, transposon mutant libraries have long been used to identify genes important for bacterial survival, growth or virulence. These methods have been very useful but time consuming as they relied on the analyses of individually isolated mutants. Moreover, they did not allow an exhaustive study of the bacterial genome. Recent advances in high throughput sequencing now allow the screening of millions of mutants in a single or few experiments using methods such as TraDIS or Tn-seq. These methods are sensitive enough to detect small defects in mutant fitness and allow the study not only of genes but also intergenic regions, promoter regions and essential protein domains in coding sequences if the library is saturated with transposon insertions.Here, we present the construction and the characterization of two saturated libraries in Salmonella Typhimurium ATCC 14028 and S. Enteritidis LA5 virulent strains, which are commonly used in research laboratories. Those libraries have been obtained using the Himar1 transposon that randomly inserts into TA dinucleotides sites on the genome. Those sites are present throughout the genome and there are few hot spots at the pathogenicity islands that have a lower GC%. Insertion of the transposon was obtained by conjugation between an E. coli donor strain harboring the plasmid pSAM_Ec (Kanamycin Himar transposon) and the Salmonella strain of interest. Transposon mutant libraries were sequenced with an Illumina NextSeq 500 using a read length of 75 bp. After read mapping, further analyses were carried out with the TRANSIT software that uses a Bayesian method based on the length of sequences containing TA sites without insertion completed with a Hidden Markov Model (HMM), which considers local differences in the read counts. These analyses confirmed the saturation of the transposon mutant libraries both on the chromosome and on the virulence plasmid and allowed us to to determine for each serovar the essential genes and the genes providing advantage or disadvantage for bacterial growth. These Tn-seq libraries are now used in several research projects and are available to the scientific community through collaboration

Construction and characterization of a saturated Tn-seq library of Salmonella Typhimurium ATCC 14028

International audienceSalmonella enterica is an important foodborne pathogen. Here, we present the construction and characterization of a high-density transposon sequencing library of the Salmonella Typhimurium ATCC 14028 strain. Essential, advantageous, and disadvantageous genes for growth in rich culture medium were identified on the chromosome and the pSLT plasmid

Transposon sequencing reveals the essential gene set and genes enabling gut symbiosis in the insect symbiont Caballeronia insecticola

Abstract Caballeronia insecticola is a bacterium belonging to the Burkholderia genus sensu lato , able to colonize multiple environments like soils and the gut of the bean bug Riptortus pedestris . To identify the essential genome of a bacterium is a first step in the understanding of its lifestyles. We constructed a saturated Himar1 mariner transposon library and revealed by transposon-sequencing (Tn-seq) that 498 protein-coding genes constitute the essential genome of C. insecticola for growth in free-living conditions. By comparing essential gene sets of C. insecticola and seven related Burkholderia s.l. strains, only 120 common genes were identified indicating that a large part of the essential genome is strain-specific. In order to reproduce specific nutritional conditions that are present in the gut of R. pedestris , we grew the mutant library in minimal media supplemented with candidate gut nutrients and identified several condition-dependent fitness-defect genes by Tn-seq. To validate the robustness of the approach, insertion mutants in six fitness genes were constructed and their growth-deficiency in media supplemented with the corresponding nutrient was confirmed. The mutants were further tested for their efficiency in R. pedestris gut colonization, confirming that gluconeogenic carbon sources, taurine and inositol, are nutrients consumed by the symbiont in the gut

Rapid detection of bacterial meningitis using a point-of-care glucometer

International audienc

Identification and pharmacological properties of E339–3D6, the first nonpeptidic apelin receptor agonist

International audienceApelin plays a prominent role in body fluid and cardiovascular homeostasis. To explore further upstream the role played by this peptide, non-peptidic agonists and antagonists of the apelin receptor are required. To identify such compounds which do not exist to date, we used an original Fluorescence Resonance Energy Transfer-based assay to screen a GPCR-focused library of fluorescent compounds on the human EGFP-tagged apelin receptor. This led to isolate E339-3D6 that displayed a 90 nmol/L affinity, behaved as a partial agonist with regard to cAMP production and as a full agonist with regard to apelin receptor internalization. Finally, E339-3D6 induced vasorelaxation of rat aorta precontracted with noradrenaline and potently inhibited systemic vasopressin release in water-deprived mice when intracerebroventricularly injected. This compound represents the first non-peptidic agonist of the apelin receptor, the optimization of which will allow to develop a new generation of vasodilator and aquaretic agents