Citrulline: from metabolism to therapeutic use.: citrulline: metabolism and therapeutic

International audienceCitrulline possesses a highly specific metabolism that bypasses splanchnic extraction because it is not used by the intestine or taken up by the liver. The administration of citrulline may be used to deliver available nitrogen for protein homeostasis in peripheral tissues and as an arginine precursor synthesized de novo in the kidneys and endothelial and immune cells. Fresh research has shown that citrulline is efficiently transported across the intestinal luminal membrane by a set of transporters belonging to the B⁰,⁺, L, and b⁰,⁺ systems. Several pharmacokinetic studies have confirmed that citrulline is efficiently absorbed when administered orally. Oral citrulline could be used to deliver arginine to the systemic circulation or as a protein anabolic agent in specific clinical situations, because recent data have suggested that citrulline, although not a component of proteins, stimulates protein synthesis in skeletal muscle through the mammalian target of rapamycin signaling pathway. Hence, citrulline could play a pivotal role in maintaining protein homeostasis and is a promising pharmaconutrient in nutritional support strategies for malnourished patients, especially in aging and sarcopenia

Diagnosis of chylous abdominal effusions: what is the triglyceride threshold value?

IntroductionChylous abdominal effusions are serious complications that can be triggered by various aetiologies. The biochemical diagnosis of chyle leakage in ascites or in peritoneal fluid capsules relies on the detection of chylomicrons. Assaying the fluid’s concentration of triglycerides is still the first-line tool. Given that only one comparative study has sought to quantify the value of the triglyceride assay for diagnosing chylous ascites in humans, our objective was to provide practical triglyceride thresholds. Materials and methodsWe conducted a 9-year, retrospective, single-centre study of adult patients and compared a triglyceride assay with lipoprotein gel electrophoresis for the analysis of 90 non-recurring abdominal effusions (ascites and abdominal collections) of which 65 were chylous. ResultsA triglyceride threshold of 0.4 mmol/L was associated with a sensitivity > 95%, and a threshold of 2.4 mmol/L was associated with a specificity > 95%. According to Youden index, the best threshold was 0.65 mmol/L with a sensitivity of 88 (77-95)%, a specificity of 72 (51-88)%, and, in our series, a positive predictive value of 89 (79-95)% and a negative predictive value of 69 (48-86)%. ConclusionsIn our series, cut-off of 0.4 mmol/L could be used for ruling-out diagnosis of chylous effusions, while cut-off of 2.4 mmol/L could be used for reasonably confirming diagnosis

EXAFS characterization of oxaliplatin anticancer drug and its degradation in chloride media.

Oxaliplatin is a second-generation platinum-based anticancer drug. Its degradation is studied in solution, in the presence of chloride ions (in neutral or acidic media) in excess. In both cases the degradation product precipitates immediately. The EXAFS spectra of these products show that they are identical. EXAFS modeling and refinement of the first coordination sphere shows that two light atoms are replaced by two chloride ions. The complete refinement of the local structure is possible by studying the multiple-scattering signal. The results show that the main multiple-scattering contribution is due to the binding oxalato group and that the degradation product is [Cl(2)-(diaminocyclohexane)-Pt(II)]

Cycle de vie des systèmes informatisés (application à un logiciel d'exécution de fabrication)

PARIS-BIUP (751062107) / SudocSudocFranceF

Développement d'une interface pour une base de données concernant la nutrition parentérale

PARIS-BIUP (751062107) / SudocSudocFranceF

DEVELOPPEMENT D'OUTILS INFORMATIQUES ET STATISTIQUES POUR L'ANALYSE DES SPECTRES EXAFS - APPLICATION AUX SYSTEMES BIOINORGANIQUES

ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Mise en place des contrôles d'adhérence dans la gestion des essais cliniques

PARIS-BIUP (751062107) / SudocSudocFranceF

Métabolisme de la citrulline

PARIS-BIUP (751062107) / SudocSudocFranceF

Base de données concernant la nutrition artificielle

PARIS-BIUP (751062107) / SudocSudocFranceF

Heckman imputation models for binary or continuous MNAR outcomes and MAR predictors

Abstract Background Multiple imputation by chained equations (MICE) requires specifying a suitable conditional imputation model for each incomplete variable and then iteratively imputes the missing values. In the presence of missing not at random (MNAR) outcomes, valid statistical inference often requires joint models for missing observations and their indicators of missingness. In this study, we derived an imputation model for missing binary data with MNAR mechanism from Heckman’s model using a one-step maximum likelihood estimator. We applied this approach to improve a previously developed approach for MNAR continuous outcomes using Heckman’s model and a two-step estimator. These models allow us to use a MICE process and can thus also handle missing at random (MAR) predictors in the same MICE process. Methods We simulated 1000 datasets of 500 cases. We generated the following missing data mechanisms on 30% of the outcomes: MAR mechanism, weak MNAR mechanism, and strong MNAR mechanism. We then resimulated the first three cases and added an additional 30% of MAR data on a predictor, resulting in 50% of complete cases. We evaluated and compared the performance of the developed approach to that of a complete case approach and classical Heckman’s model estimates. Results With MNAR outcomes, only methods using Heckman’s model were unbiased, and with a MAR predictor, the developed imputation approach outperformed all the other approaches. Conclusions In the presence of MAR predictors, we proposed a simple approach to address MNAR binary or continuous outcomes under a Heckman assumption in a MICE procedure