Label-free higher order structure and dynamic investigation method of proteins in solution using an enzymatic reactor coupled to electrospray high-resolution mass spectrometry

peer reviewe

Investigation of structure-stabilizing elements in proteins by ion mobility mass spectrometry and collision-induced unfolding

peer reviewe

Simultaneous detection and quantification of angiotensin I, II, 1-7 and 1-9 by LC-MS/MS in human plasma

peer reviewedRecent studies showed that angiotensin-converting 2 (ACE2) is used by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as a cellular entry receptor. SARS-CoV-2 causes down regulation of ACE2 leading to renin-angiotensin-aldosterone system (RAAS) major imbalance. This is an essential element of unfavourable evolution in patients with COVID-19. With lower level of ACE2, cleavage of And I and And II is decrease and therefore, And 1-7 and And 1-9 levels are decreased. The development of a quantitative method for these angiotensins is particularly interesting in the context of the prognosis/follow-up of patients with COVID-19. Based on this, this work aims at assessing angiotensins profile variations occurring over time with patients COVID-19 + using a LC-MS/MS method. In this project, plasma samples are prepared with an microelution MAX plate before injection on a Vexera X2 UPLC (Shimadzu Corporation, Kyoto, Japan) coupled to a QT5500 mass spectrometer (Scion, CA, USA) fitted with an IonDriveTMTurbo V ion source and using electro spray ionisation in positive mode. The mobile phase are composed of water (+0,4% formic acid) and of acetonitrile (+0,4% formic acid)

Iohexol quantitation and possible degradation kinetics in human urine using mass spectrometry coupled to liquid chromatography (LC)

peer reviewedIohexol is a well-known marker used to evaluate glomerular filtration rate (GFR) which is one indicator of kidney function. This GFR in often calculated using Iohexol intensity decay calculated using LC-MS/MS approaches on human plasma and urines. In these approaches, urines or plasma are taken from patients who were administered Iohexol at different timepoints and Iohexol is quantified at each time using one MRM approach. Once those value obtained, kinetics can be performed and GFR is calculated. However, some discrepancies can occur between urine and plasma results from the same patient and no study clearly explained this. Based on this, this work aims at assessing molecule profile variations occurring over time with patients that took Iohexol using LC coupled with high resolution mass spectrometry. In this project, urine samples are taken at given timepoints from patients who received Iohexol. The samples are first centrifuged, and the supernatant is diluted 100 times with water before injection in a NanoACQUITY UPLC system coupled with a SYNAPT XS instrument operating in positive ion mode. The mobile phases are composed of water (+0.1% formic acid) and of acetonitrile (+0.1% formic acid). Standard samples (commercial Iohexol drug) are also analyzed as quality control. The Iohexol LC-MS/MS method on a triple quadripole instrument has successfully been implemented on the SYNAPT XS – NanoACQUITY UPLC system. The first results on different patient urines show the presence of other peaks that Iohexol in patient samples. Interestingly, those peaks are not present in standards and in urines of patients who did not receive the drug. Investigation of all mass spectra is in progress and these results open the possibility for a large screening over time. Comparison with data obtained using LC-MS/MS is also in progress and the next step is the comparison with data obtained on plasma samples

LABORATORY EXPLORATION OF A VERY HIGH LEVEL OF INSULIN MEASURED IN A LONG-STANDING TYPE 1 DIABETIC PATIENT.

peer reviewe

Towards B-CTX characterization

peer reviewe

Détection et quantification simultanée des angiotensines 1-7, 1-8, 1-9 et 1-10 par LC-MS/MS dans le plasma humain

peer reviewe