References of "Nys, Gwenaël"
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See detailCE-MS/MS for bottom-up proteomics: comparaison of two coupling interfaces with ion mobility qTOF
Gou, Marie-Jia ULiege; Nys, Gwenaël ULiege; COBRAIVILLE, Gaël ULiege et al

Conference (2019, May 20)

Untargeted bottom-up proteomic analysis aims to identify the highest number of peptides from complex protein mixtures. As the samples are of high complexity and that some proteins can be at very low ... [more ▼]

Untargeted bottom-up proteomic analysis aims to identify the highest number of peptides from complex protein mixtures. As the samples are of high complexity and that some proteins can be at very low concentrations, efficient and sensitive instruments have to be used in order to maximize peptide identification. Nowadays, capillary electrophoresis tandem mass spectrometry (CE-MS/MS) has gained interest in proteomic analysis as it is considered as complementary to the gold standard method, namely reverse phase liquid chromatography tandem mass spectrometry (RP-LC-MS/MS). However, the coupling of CE with MS is not straightforward. Indeed robust interface is needed in order to conserve the high-resolution in-capillary separation while ensuring a stable spray. Among the commercialized interfaces, the coaxial sheath liquid interface (« Triple tube », Agilent Technologies) and the nanoflow sheath liquid interface (« EMASS-II », CMP Scientific) have been tested for the analysis of BSA and E. coli proteome digests. Both interfaces were coupled with an IMS-qTOF-MS. Several parameters were optimized in order to maximize the sensitivity, such as the composition of the sheath liquid and different pre-concentration approaches (stacking, dynamic pH junction and transient isotachophoresis). In our study, transient isotachophoresis (tITP) was selected among other techniques and allowed the injection of large sample volumes without sacrificing separation efficiency. At the end, spray stability was found as the main strength of the triple tube interface, whereas the EMASS-II interface was found to provide higher sensitivity thanks to the reduced flow rate of the sheath liquid. [less ▲]

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See detailDevelopment of injectable liposomes and drug-in-cyclodextrin-in-liposome formulations encapsulating estetrol to prevent cerebral ischemia of premature babies.
Palazzo, Claudio; Laloy, Julie; Delvigne, Anne Sophie et al

in European Journal of Pharmaceutical Sciences (2019), 9(127), 52-59

Neonatal Hypoxic-Ischemic Encephalopathy (HIE), a brain disease due to brain hypoxia along with ischemia and reduced cerebral blood flow, is one of the primary reasons of severe injury among babies ... [more ▼]

Neonatal Hypoxic-Ischemic Encephalopathy (HIE), a brain disease due to brain hypoxia along with ischemia and reduced cerebral blood flow, is one of the primary reasons of severe injury among babies prematurely born. No efficacy treatment is available to the present day. Estetrol (E4), a major estradiol metabolite, has an important role in the brain development and protection. The aim of this study is to develop new injectable liposome and drug-in-cyclodextrin-in-liposome (DCL) formulations, encapsulating E4 in order to enhance its crossing through the blood-brain barrier (BBB). Liposome and DCL formulations were prepared and were physiochemically characterized. Stability in foetal bovine serum (FBS) was evaluated. LDH and MTS tests on endothelial, neuronal and BBB model cells, as well as hemocompatibility of the nanovectors were performed in vitro. In vitro BBB passage was evaluated using human BBB cell line (hCMEC/D3). All the formulations had average particle size below 150 nm, polydispersity index below 0.10 and ζ potential around + 30 mV. The encapsulation efficacy for liposomes was between 3% and 10% while those of DCL are between 15% and 35%. The effect of liposome and DCL formulations on cell viability and integrity was evaluated. The results showed no toxic effects on all the tested cell lines. Hemocompatibility tests showed no hemolysis, platelet aggregation or effects on coagulation, confirming the possibility of the formulations to be intravenously administrated. BBB passage tests highlighted the capability of the formulations to pass the BBB and reach the brain. Therefore, the formulations are promising drug delivery system to target estrogens to the brain, due to their physiochemical characteristics. [less ▲]

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See detailUltra-high-performance liquid chromatography-mass spectrometry method for neutrophil gelatinase-associated lipocalin as a predictive biomarker in acute kidney injury
Ion, Valentin ULiege; Nys, Gwenaël ULiege; COBRAIVILLE, Gaël ULiege et al

in Talanta (2019), 195

Neutrophil gelatinase associated lipocalin (NGAL) is a protein that was found to be overexpressed in acute kidney injury (AKI). The rise in NGAL concentration, both in urine or plasma, appears earlier ... [more ▼]

Neutrophil gelatinase associated lipocalin (NGAL) is a protein that was found to be overexpressed in acute kidney injury (AKI). The rise in NGAL concentration, both in urine or plasma, appears earlier than for other classical renal function markers such as serum creatinine, thus making it a suitable marker for early pathology detection. The aim of this study was to develop a method involving tryptic digestion, solid phase extraction and LC-MS/MS analysis to analyze NGAL in plasma medium using an isotope labeled surrogate protein, containing NGAL signature tags, as internal standard (QPrEST). The method was validated for the analysis of NGAL in an analytical range from 50 to 1250 ng/mL using two different proteotypic peptides. The method was further used to quantify the NGAL in human plasma samples for whom elevated NGAL values were expected. NGAL values were between 190.8 and 242.6 ng/mL for control group and between 228.1 and 3526.2 ng/mL for patient group. This study proved that the selection of the right internal standard is of utmost importance in targeted proteomics studies as the digestion steps might cause high variability. This study also confirmed that, although NGAL is highly resistant to proteases such as trypsin, the method could be fully validated according to FDA guidelines and subsequently used to assess NGAL levels in patient plasma with high analytical confidence. © 2018 [less ▲]

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See detailVolumetric absorptive microsampling for targeted metabolomics of whole blood
Kok, Miranda ULiege; Nys, Gwenaël ULiege; Fillet, Marianne ULiege

Conference (2018, May 23)

Volumetric absorptive microsampling (VAMS) enables the collection of small and accurate quantities of biological fluids. Therefore, this sampling technique is of great interest for volume-limited samples ... [more ▼]

Volumetric absorptive microsampling (VAMS) enables the collection of small and accurate quantities of biological fluids. Therefore, this sampling technique is of great interest for volume-limited samples or serial collection of samples. Here, we present and discuss the potential of VAMS for targeted mass spectrometry (MS)-based metabolomics. In total, 24 amino acids and 12 organic acids were selected as target metabolites. Two ultra-high performance liquid chromatography (UHPLC) methods coupled to tandem MS have been developed and optimized for the separation and quantitation of these metabolites. A reversed-phase UHPLC-MS/MS method was used to analyze organic acids, whereas hydrophilic interaction chromatography (HILIC)-MS/MS was selected for the determination of amino acids. VAMS devices were used to collect 10 µL of whole blood via a simple finger prick. After collection, the samples were dried for two hours before sample preparation. A design of experiments was conducted to find an extraction solvent providing the maximum recovery of the target analytes from the dried VAMS samples. Overall, the optimum extraction solvent was acetonitrile-water in a proportion of 60:40 (v/v), resulting in the detection of all target metabolites in whole blood with good repeatability. Furthermore, the stability of the analytes in dried whole blood supported on VAMS devices was investigated. We showed that the amino and organic acids were stable for at least 4 days when stored at room temperature. This is in contrast to the instability of these compounds in blood, thereby showing great possibilities of VAMS in metabolomics studies. [less ▲]

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See detailCapillary electrophoresis, high-performance liquid chromatography, and thin-layer chromatography analyses of phenolic compounds from rapeseed plants and evaluation of their antioxidant activity.
Huang, Yang; Jansen, Olivia ULiege; Frederich, Michel ULiege et al

in Journal of Separation Science (2018)

Rapeseed plants, known for oil production, are also known to contain phenolic compounds such as phenolic acids and flavonoids, with potential antioxidant and anticancer activities. The separation and ... [more ▼]

Rapeseed plants, known for oil production, are also known to contain phenolic compounds such as phenolic acids and flavonoids, with potential antioxidant and anticancer activities. The separation and identification of 11 phenolic acids in rapeseed extracts (including leaves, flowers, Chinese seeds, Belgian seeds, and cake) by capillary electrophoresis were investigated. The results were compared with those obtained with high-performance liquid chromatography and thin-layer chromatography and showed that the capillary electrophoresis technique offers several advantages for the identification of phenolic compounds in various rapeseed extracts. The antioxidant activity of rapeseed extracts and reference compounds was evaluated using four different approaches, namely, 2,2'-azinobis- (3-ethylbenzohiazoline-6-sulfonic acid assay, free radical 2,2-diphenyl-1-picrylhydrazyl assay, electron paramagnetic resonance spectroscopy and the measurement of the total polyphenol content. The contents of total polyphenols in the tested extracts were ranging between 5.4 and 21.1% m/m and ranked as follows: Chinese seeds > Belgian seeds > Flowers > Cake > Leaves. [less ▲]

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See detailBeyond dried blood spot: Current microsampling techniques in the context of biomedical applications
Nys, Gwenaël ULiege; Kok, Miranda ULiege; Servais, Anne-Catherine ULiege et al

in TrAC: Trends in Analytical Chemistry (2017), 97

Detailed reference viewed: 34 (5 ULiège)
See detailMetabolomic and proteomic biomarker quantification in the context of personalized medicin
Nys, Gwenaël ULiege; Kok, Miranda ULiege; Fillet, Marianne ULiege

Scientific conference (2017, November 14)

Présentation de résultats concernant l'étude de biomarqueurs protéiques dans le cadre des affections rhumatologiques.

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See detailComparison of nanofluidic and ultra-high performance liquid chromatography-tandem mass spectrometry for high sensitive pharmacokinetic studies of estrogens starting from whole blood microsampling
Nys, Gwenaël ULiege; COBRAIVILLE, Gaël ULiege; Kok, Miranda ULiege et al

in Journal of Chromatography. A (2017), 1524

Pharmacokinetic (PK) studies on small animals are challenging as only small volumes of samples are available, in which the analyte is present at low concentration in a complex matrix. In this context, the ... [more ▼]

Pharmacokinetic (PK) studies on small animals are challenging as only small volumes of samples are available, in which the analyte is present at low concentration in a complex matrix. In this context, the use of miniaturized analytical techniques may provide undeniable advantages in terms of sensitivity, sample and solvent consumption compared to the reference UHPLC-MS/MS methods In this study, we present the development of a nanofluidic-LC-MS/MS method to analyze two model analytes of therapeutic interest, namely estradiol (E2) and estetrol (E4) after microsampling with volumetric absorptive microsampling (VAMS) devices, an innovative sampling technique to collect small volumes of whole blood. The nanofluidic LC-MS/MS method was developed using an experimental design to find the optimal conditions to analyze both E2 and E4 with the highest sensitivity. Subsequently, the optimized method was validated according to ICH guidelines and compared to a previously developed UHPLC-MS/MS method. A limit of quantitation of 50. pg/ml was reached with the LC-chip method, which is 50 times better than UHPLC-MS/MS. Both methods were then critically evaluated from the analytical and operational points of view. Finally, the quantitation of estrogens after whole blood microsampling was compared with the results obtained with the corresponding plasma samples. © 2017 Elsevier B.V. [less ▲]

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See detailSampling only 10 μL of whole blood to study the bioavailability of itraconazole formulations in rats
Kok, Miranda ULiege; Thiry, Justine ULiege; Evrard, Brigitte ULiege et al

Conference (2017, September 12)

Background Volumetric absorptive microsampling (VAMS) offers a unique opportunity to collect small and accurate quantities of biological fluids. This sampling technique is of great interest for volume ... [more ▼]

Background Volumetric absorptive microsampling (VAMS) offers a unique opportunity to collect small and accurate quantities of biological fluids. This sampling technique is of great interest for volume-limited samples and for the collection of multiple samples from the same animal. This serial sample collection may reduce the number of required study animals, thereby fulfilling the three Rs rule (refine, reduce, replace). Here, we demonstrate the applicability of VAMS to study the bioavailability of drug formulations in rats. Methods Four itraconazole-containing formulations were successively administered to rats with a wash-out period of one week. VAMS was used to collect 14 whole blood samples of only 10 μL each within a time frame of 48 hours after administration of the different drug formulations. Particular attention was paid to sample preparation and stability. The extraction of itraconazole and its main metabolite hydroxy-itraconazole was optimized to provide a high recovery and minimal matrix effects. A developed and validated LC–MS/MS method was used for the quantification of the two compounds. Pharmacokinetic profiles for the different formulations were constructed and compared. Results The stability of itraconazole and hydroxy-itraconazole in dried VAMS samples of whole rat blood could not be guaranteed for more than a day when the samples were stored at room temperature. However, samples were stable for at least two weeks when stored at -80°C after sample preparation. Differences in pharmacokinetic profiles were observed for the tested drug formulations. Whole blood concentrations of itraconazole and its main metabolite were significantly higher after administration of three in-house produced formulations compared to concentrations obtained with a commercially available product. Moreover, these in vivo results could be partly related to in vitro dissolution rates of the various formulations. Conclusions VAMS is an attractive approach for bioavailability studies. Due to the low blood volumes per sampling point, the same rats can be used to compare various drug formulations. Therefore, the number of required animals can be drastically reduced. Moreover, this helps to suppress the inter-individual variability and strengthens the validity of results. [less ▲]

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See detailWhole blood microsampling for the quantitation of estetrol without derivatization by liquid chromatography-tandem mass spectrometry
Nys, Gwenaël ULiege; Gallez, Anne ULiege; Kok, Miranda ULiege et al

in Journal of Pharmaceutical and Biomedical Analysis (2017), 140

Detailed reference viewed: 69 (37 ULiège)