scholarly journals Comprehensive high-resolution multiple-reaction monitoring mass spectrometry for targeted eicosanoid assays

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Carlos Artério Sorgi ◽  
Ana Paula Ferranti Peti ◽  
Tania Petta ◽  
Alyne Fávero Galvão Meirelles ◽  
Caroline Fontanari ◽  
...  
Author(s):  
Tanize Acunha ◽  
Viviani Nardini ◽  
Ana Paula Ferranti Peti ◽  
Morgana Kelly Borges Prado ◽  
Luiz Alberto Beraldo Moraes ◽  
...  

2015 ◽  
Vol 115 ◽  
pp. 36-48 ◽  
Author(s):  
Louis Tong ◽  
Xi Yuan Zhou ◽  
Antti Jylha ◽  
Ulla Aapola ◽  
Dan Ning Liu ◽  
...  

2014 ◽  
Vol 60 (2) ◽  
pp. 353-360 ◽  
Author(s):  
Lynn Carr ◽  
Anne-Laure Gagez ◽  
Marie Essig ◽  
François-Ludovic Sauvage ◽  
Pierre Marquet ◽  
...  

Abstract BACKGROUND Blood concentrations of the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus are currently measured to monitor immunosuppression in transplant patients. The measurement of calcineurin (CN) phosphatase activity has been proposed as a complementary pharmacodynamic approach. However, determining CN activity with current methods is not practical. We developed a new method amenable to routine use. METHODS Using liquid chromatography–multiple reaction monitoring mass spectrometry (LC-MRM-MS), we quantified CN activity by measuring the dephosphorylation of a synthetic phosphopeptide substrate. A stable isotope analog of the product peptide served as internal standard, and a novel inhibitor cocktail minimized dephosphorylation by other major serine/threonine phosphatases. The assay was used to determine CN activity in peripheral blood mononuclear cells (PBMCs) isolated from 20 CNI-treated kidney transplant patients and 9 healthy volunteers. RESULTS Linearity was observed from 0.16 to 2.5 μmol/L of product peptide, with accuracy in the 15% tolerance range. Intraassay and interassay recoveries were 100.6 (9.6) and 100 (7.5), respectively. Michaelis–Menten kinetics for purified CN were Km = 10.7 (1.6) μmol/L, Vmax = 2.8 (0.3) μmol/min · mg, and for Jurkat lysate, Km = 182.2 (118.0) μmol/L, Vmax = 0.013 (0.006) μmol/min · mg. PBMC CN activity was successfully measured in a single tube with an inhibitor cocktail. CONCLUSIONS Because LC-MRM-MS is commonly used in routine clinical dosage of drugs, this CN activity assay could be applied, with parallel blood drug concentration monitoring, to a large panel of patients to reevaluate the validity of PBMC CN activity monitoring.


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