HAL Portal ESPCI (Ecole Supérieure de Physique et de Chimie Industrielles)
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Highly Sensitive Detection of Glucose in the Presence of Serum Based on Signal Amplification of Persistent Luminescence Nanoparticles Functionalized by Glucose Oxidase
No full textInternational audienceA new method is presented for the in vitro detection of glucose using glucose oxidase (GOx) covalently linked to persistent luminescent nanoparticles (PLNPs). This method ensures both sensitive and specific glucose detection by exploiting the enhanced luminescence of PLNPs in the presence of H 2 O 2 , generated by an enzymatic reaction. To this end, three different PLNPs composed of ZnGa 2 O 4 :Cr 3+ (ZGO) nanoparticles are prepared by hydrothermal synthesis at 120 °C for 6 h (ZGO1), 12 h (ZGO2), and 24 h (ZGO3), followed by a calcination at 500 °C, resulting in nanoparticles with an average hydrodynamic diameter of 100 nm ± 5 nm after grinding and centrifugation. These nanoparticles are efficiently covalently functionalized with GOx, via a PEG linker. Following the production of H 2 O 2 by the enzymatic reaction between GOx bound to the ZGO surface and glucose present in 100‐fold diluted serum, a significant increase in the persistent luminescent signal is observed. This phenomenon is most pronounced for ZGO2, for which a detection limit of 0.01 µ m and a detection range from 0.05 to 1 µ m is obtained. These results demonstrate the innovative potential of this new technique in glucose monitoring, opening up new avenues for real‐time monitoring and effective management of diabetes
Développement de nouvelles méthodes de traitement et d’analyse par chromatographie liquide couplée à la spectrométrie de masse en tandem (LC-MS/MS) de biomarqueurs sanguins de toxiques de guerre
No full textBlister agents are highly alkylating toxic compounds used as chemical warfare agents. They can react with blood proteins, including albumin, forming stable adducts. These adducts, which have a lifespan of 20 to 25 days, can be used as biomarkers to retrospectively demonstrate exposure to such agents. The aim of this PhD was the development of a sample preparation and LC-MS analysis method. Monitoring biomarkers of five different blister agents in pure media was achieved using both reversed-phase (RP) and hydrophilic interaction chromatography (HILIC) modes. The sensitivity of these methods towards two families of albumin-adduct biomarkers of blister agents allowed for the selection of the enzyme to be used for the digestion step, namely proteinase K. An online solid-phase extraction (SPE) procedure was developed using commercial supports to treat the digests and facilitate the monitoring of the adducted peptides in real matrices. Protein precipitation, commonly used in published procedures, and protein reduction with DTT, which had never been applied to blister agent analysis, were investigated. The impact of these steps on the LC-MS signal of the SM-adducted tripeptide in plasma incubated with SM was evaluated. These steps did not result in increased sensitivity and were therefore omitted to reduce the overall analysis time. Online digestion on an immobilized enzyme reactor (IMER), replacing the enzyme-intensive In solution digestion step, was considered in order to automate the entire analytical workflow. The proteinase K IMERs developed showed lower activity compared to the free enzyme but still enabled the detection of SM adduction at the monitored site through the associated biomarker ion a fully automated procedure.Les vésicants sont de agents toxiques fortement alkylants utilisés comme agents de guerre pouvant réagir avec les protéines du sang, dont l'albumine formant des adduits stables. Ces adduits de durée de vie comprise entre 20 et 25 jours peuvent être utilisés comme biomarqueurs pour mettre en évidence à posteriori l'exposition à ces agents. L'objectif de cette thèse a été le développement d'une méthode de traitement de l'échantillon et d'analyse par LC-MS Le suivi des biomarqueurs de cinq vésicants en milieu pur a été possible en chromatographie liquide en mode RP ainsi qu'en mode HILIC. Les sensibilités de ces méthodes vis-à-vis de deux familles de biomarqueurs des vésicants adduits sur l'albumine ont permis de sélectionner l'enzyme à utiliser pour réaliser l'étape de digestion enzymatique, à savoir la protéinase K. Une procédure d'extraction sur phase solide (SPE) en ligne a été développée sur supports commerciaux afin de traiter les digestats et faciliter le suivi des peptides adduits lors de leur suivi en matrice réelle. La précipitation protéique, fréquemment rencontrée dans les procédures décrites dans la littérature et la réduction protéique au DTT jamais appliquée au suivi des vésicants ont été étudiées. Ainsi, l'impact de ces étapes sur le signal en LC-MS du tripeptide adduit par SM dans le cas l'analyse d'un plasma incubé par SM a été mesurée, ces étapes n'ont pas conduit à un gain dans la sensibilité et n'ont donc pas été maintenues afin de réduire la durée globale d'analyse. La digestion en ligne sur un réacteur d'enzyme immobilisée (IMER), en remplacement de l'étape de digestion en solution fortement consommatrice d'enzymes, a été envisagée afin de pouvoir automatiser l'ensemble de la procédure d'analyse. Les IMER de protéinase K développés ont montré une plus faible activité que l'enzyme libre mais ont malgré tout permis de mettre en évidence l'adduction de SM sur le site d'adduction suivi par détection du biomarqueur associé via une méthode totalement automatisable
Empagliflozin in Acute Myocardial Infarction Reduces No-Reflow and Preserves Cardiac Function by Preventing Endothelial Damage
No full textInternational audienceEmpagliflozin treatment before acute myocardial infarction mainly targets the endothelial cell transcriptome. Empagliflozin treatment before and after myocardial infarction decreased no reflow and microvascular injury, leading to reduced infiltration of inflammatory cells, reduced infarct size, and improved cardiac function in mice. In diabetic patients receiving empagliflozin after myocardial infarction, perfused boundary region, flow-mediated dilation, and global longitudinal strain were improved
Fluid balance after cardiac arrest: Any impact on outcome? Insights from the MIMIC IV database
No full textInternational audienceBackground. Fluid balance is closely associated with outcomes in septic shock. Post-cardiac arrest (CA) shock, which accounts for one-third of deaths after CA, shares many pathophysiological features with sepsis. However, the impact of fluid balance has not been analyzed in this setting. This study aimed to assess the impact of fluid balance on mortality during post-CA shock.Methods. This retrospective study used the Medical Information Mart for Intensive Care (MIMIC)-IV database. Fluid balance was quantified during the first 72 h. Multivariate logistic-regression analysis identified factors associated with early (by day 3) mortality.Results. Among the 1800 patients resuscitated from CA, 868 (68 %) developed post-CA shock. Of these, 801 were analyzed; 334 (42 %) died within 3 days. Early non-survivors had a higher median fluid balance (+3289 mL [25th; 75th IQR + 502; +5806]) than early survivors (+930 mL [–2677; +4353]) (P < 0.001). Positive fluid balance independently predicted death by day 3 (OR 2.23, 95 % CI [1.29; 3.14]; P = 0.005). Mortality increased significantly with increasing fluid balance, especially from 1000 mL and upwards (OR 4.11, 95 % CI [2.32; 2.47]; P < 0.001). Other factors independently associated with early mortality included age >66 years, maximum catecholamines dose, and peak serum lactate.Conclusions. These findings confirm that fluid balance is associated with early mortality during post-CA shock
Molecular Catalyst Enables CO2 Electroreduction at 650 mA/cm2 CO Partial Current Density
No full textInternational audienceThe electrochemical reduction of CO2 to CO using renewable electricity offers a compelling pathway for greenhouse gas recycling. The two-electron, two-proton process is particularly attractive due to its operational simplicity and scalability, with copper-and silver-based nanomaterials being the most widely studied catalysts as the field approaches industrial maturity. However, achieving the necessary efficiency and stability for practical application remains a significant challenge. Recently, molecular catalysts immobilized on conductive surfaces with carbon-based inks have emerged as highly tunable hybrid systems capable of remarkable selectivity. In this work, we report that a straightforward cobalt phthalocyanine complex, simply modified with a single trimethylammonium group, delivers outstanding CO2-to-CO conversion rates and selectivity-reaching a Faradaic efficiency of 93% at a total current density of 700 mA/cm 2 (jCO 650 mA/cm 2 ) at neutral pH. Notably, CO selectivity above 90% was sustained for over 42 hours at 150 mA/cm 2 , illustrating the potential of simply designed molecular catalysts for large scale applications
Effect of bubble size on the stability of flowing liquid films in binary oil mixtures
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Nicotine disrupts top down habenular control over cholinergic inputs to the ventral tegmental area to increase motivational valence of food rewards
No full textInternational audienceThis is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain
Unusual planar anisotropy of the induced magnetism in KTb<sub>3</sub>F<sub>10</sub>
No full textInternational audienceThe magnetic ground state of KTb3F10 was investigated using a combination of magnetization measurements and neutron scattering experiments, carried out on either a polycrystal or a single-crystal sample. Results show that Tb3 remains in a crystalline electric field singlet state down to 30 mK. A susceptibility tensor analysis performed on a comprehensive neutron single-crystal diffraction dataset shows that the induced magnetism observed when applying a magnetic field is highly anisotropic, magnetic moments being confined within local anisotropy planes. These features can be well captured by a detailed analysis of the Tb3+crystal field scheme, combining point charge modeling and inelastic neutron scattering measurements in zero and applied magnetic field. Moreover, the local singlet ground state is protected by a large 2.7 meV gap, which the weak magnetic interactions between Tb moments are too weak to overcome, thereby preventing the formation of a magnetic ground state. Within this approximation, an estimate of the magnetic exchanges was extracted from the magnetic field evolution of the ordered Tb moments, obtained from the analysis of the diffraction data. These results provide a first step toward the understanding of the unusual magneto-optical and low thermal conductivity properties of the singlet system KTb3F10
The Metabolically Resistant Apelin-17 Analogue LIT01-196 Reduces Cardiac Dysfunction and Remodelling in Heart Failure After Myocardial Infarction
No full textInternational audienceBackground: To protect patients after myocardial infarction (MI) and preserve cardiac function, the development of new therapeutics remains an important issue. Apelin, a neuro-vasoactive peptide, increases aqueous diuresis and cardiac contractility while reducing vascular resistance. However, its in vivo half-life is very short. We therefore developed a metabolically resistant apelin-17 analogue, LIT01-196 and investigated its effects on cardiac function and remodelling in a murine MI model.Methods: The selectivity of LIT01-196 toward the apelin receptor was checked in vitro. Its in vivo half-life was assessed in male Swiss mice using radioimmunoassay. After permanent coronary artery ligation to induce MI, mice received subcutaneous administration of LIT01-196 (MI + LIT01-196, 9 mg/kg/d) or saline (MI + vehicle) for 4 weeks. Left ventricular (LV) function was assessed using echocardiography and Millar (Houston, TX) catheter, vascular density using immunofluorescence, and cardiac fibrosis using Sirius red staining. Real-time quantitative PCR was used to measure mRNA expression of heart failure (HF) fibrosis biomarkers and sarco/endoplasmic reticulum Ca2+-ATPase-2.Results: The in vivo half-life of LIT01-196, a specific and selective apelin receptor agonist, was 2.5 hours. MI + LIT01-196 showed significantly improved LV function, reduced HF biomarkers, and enhanced cardiac contractility and sarco/endoplasmic reticulum Ca2+-ATPase-2 expression compared with MI + vehicle. LIT01-196 treatment almost doubled cardiac vascular density and maintained LV wall thickness post MI. It also significantly reduced cardiac fibrosis and fibrosis biomarkers, without decreasing arterial blood pressure.Conclusions: Chronic LIT01-196 treatment post MI improves LV function without decreasing blood pressure, increases cardiac vascular density, and reduces cardiac remodelling. This suggests that apelin receptor activation by LIT01-196 might constitute an original pharmacological approach for HF treatment after MI.Contexte : Pour protéger les patients après un infarctus du myocarde (IM) et préserver la fonction cardiaque, le développement de nouvelles thérapeutiques reste une question importante. L’apéline, un peptide neuro-vasoactif, augmente la diurèse aqueuse et la contractilité cardiaque tout en réduisant la résistance vasculaire. Cependant, sa demi-vie in vivo est très courte. Nous avons donc développé un analogue de l’apeline-17 résistant au métabolisme, le LIT01-196, et nous avons étudie ses effets sur la fonction et le remodelage cardiaques dans un modèle murin d’IM. Méthodes : La sélectivité du LIT01-196 vis-à-vis du récepteur de l’apéline a été vérifiée in vitro. Sa demi-vie in vivo a été évaluée chez des souris mâles de type Swiss à l’aide d’un dosage radioimmunologique. Après ligature permanente de l’artère coronaire pour induire un IM, les souris ont reçu une administration sous-cutanée de LIT01-196 (IM þ LIT01-196, 9 mg/kg/j) ou de solution saline (IM þ vehicule) pendant 4 semaines. La fonction ventriculaire gauche (VG) a été évaluée par échocardiographie et cathéter Millar (Houston, TX), la densite vasculaire par immunofluorescence et la fibrose cardiaque par coloration au rouge Sirius. La PCR quantitative en temps réel a été utilisée pour mesurer l’expression de l’ARNm des biomarqueurs de la fibrose liée à l’insuffisance cardiaque (IC) et de la Ca2þ-ATPase-2 du réticulum sarco-endoplasmique.Résultats : La demi-vie in vivo du LIT01-196, un agoniste spécifique et sélectif du récepteur de l’apéline, était de 2,5 heures. Le groupe expérimental IM þ LIT01-196 a montre une amélioration significative de la fonction du VG, une réduction des biomarqueurs de l’IC et une amélioration de la contractilité cardiaque et de l’expression de la Ca2þATPase-2 du réticulum sarco/endoplasmique, par rapport au groupe IM + véhicule. Le traitement par LIT01-196 a presque double la densité vasculaire cardiaque et maintenu l’épaisseur de la paroi du VG après l’IM. Il a également réduit de manière significative la fibrose cardiaque et les biomarqueurs de la fibrose, sans diminuer la pression artérielle.Conclusions : Le traitement chronique par le LIT01-196 après un IM améliore la fonction VG sans diminuer la pression artérielle, augmente la densité vasculaire cardiaque et réduit le remodelage cardiaque. Cela suggère que l’activation du récepteur de l’apéline par le LIT01196 pourrait constituer une approche pharmacologique originale pour le traitement de l’IC après un IM
Differences in the Inflammatory Response and Corticoid Responsiveness of Human Lung Macrophages and Parenchymal Explants Exposed to Cigarette Smoke Extracts
No full textInternational audienceSmoking is the main cause of chronic obstructive pulmonary disease (COPD) and is associated with corticosteroid resistance. Given the paucity of data on human lung preparations, macrophages (LMs), and parenchymal explants (LPEs) were exposed to cigarette smoke extracts (CSE) in the presence or absence of lipopolysaccharide (LPS). Moreover, LMs and LPEs were treated with budesonide prior exposure to CSE or LPS. The levels of cytokines (TNF-α, IL-6) and chemokines (CCL2, CCL4, CXCL1, CXCL5, and CXCL8) in the supernatants were measured using ELISAs. In LMs, exposure to CSE was not associated with significant difference in the production of cytokines and chemokines, with the notable exception of greater CXCL8 production. The results were generally the same for LPEs. CSE exposure did not potentiate the LPS-induced production of the cytokines and chemokines and even tended to reduce this production in LMs and LPEs. Lastly, CSE exposure inhibited budesonide's anti-inflammatory activity in LMs but not in LPEs. This study extends the data on the CSE inflammatory effects and its inhibition of corticosteroid efficacy in human lung preparations. Our findings question the relevance of these preparations with regard to the long-term toxicity of smoking and the corticosteroid resistance observed in smokers and in patients with COPD