References of "Houbart, Virginie"
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See detailChallenges in the determination of amyloid oligomeric species by two electrophoretic techniques
Napp, Aurore ULiege; Houbart, Virginie ULiege; Demelenne, Alice ULiege et al

Poster (2017, September 18)

Parkinson’s disease is a frequent degenerative disorder, and for the moment the diagnosis is mainly clinical. When the first symptoms appear, loss of more than 70% of the dopaminergic cells already ... [more ▼]

Parkinson’s disease is a frequent degenerative disorder, and for the moment the diagnosis is mainly clinical. When the first symptoms appear, loss of more than 70% of the dopaminergic cells already occurred. Knowing that, it is of high interest to have one (or more) reliable biomarker(s) at our disposal to diagnose Parkinson before the first symptoms appear. Alpha-synuclein (aSyn) is a protein physiologically expressed at high level by neuronal cells, under a monomeric form. This protein would play a critical role in the development of the disease because under certain conditions, aSyn is capable of self-assembly to form fibrils like those found in Lewy bodies. Other intermediate soluble forms like dimers and oligomers are also formed. As these forms seems to be the toxic species, they are the center of many attentions. The quantification of each form would be a great help, but for the moment only the total forms (of monomeric or oligomeric) can be quantified. In this study, aSyn oligomers were generated after optimization of incubation conditions (pH, temperature, agitation, …). Then, different approaches were investigated to detect and follow the different species formed during the aggregation. We analyzed the oligomers by capillary gel electrophoresis (CGE) and SDS-PAGE. We found that capillary gel electrophoresis is a promising automated technique to analyze aSyn oligomers, due to the fact that it separates the aggregates according to their size, like the SDS-PAGE, but with more advantages. To gain sensitivity and selectivity by CGE, we used a laser-induced fluorescence detector. As aSyn do not have a native fluorescence, we derivatized it. After careful screening and optimization of various derivatization reagents, we could quantify with high sensitivity aSyn oligomers by CGE-LIF. We realized different calibration curves, and we had promising results that will allow us to quantify the different aSyn oligomeric forms in biological fluids. [less ▲]

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See detailVolumetric Absorptive Microsampling for Hepcidin Peptide Extraction from Whole Blood
Houbart, Virginie ULiege; COBRAIVILLE, Gaël ULiege; Nys, Gwenaël ULiege et al

in LCGC North America (2016), 34(5),

Whole blood analysis is an emerging trend in the field of bioanalysis. We developed a fast and simple protocol to extract and analyze a peptide, hepcidin, from whole blood. Sampling and extraction were ... [more ▼]

Whole blood analysis is an emerging trend in the field of bioanalysis. We developed a fast and simple protocol to extract and analyze a peptide, hepcidin, from whole blood. Sampling and extraction were carried out using volumetric absorptive microsampling (VAMS), a novel blood collection method that allows the sampling of a known blood volume independently from hematocrit. The composition of the extraction medium was optimized using an experimental design to get the most intense signal of hepcidin, considering different organic solvents and acidic additives. [less ▲]

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See detailAlpha-synuclein as biomarker in Parkinson’s disease: strategies for detection in CGE-LIF
Houbart, Virginie ULiege; Napp, Aurore ULiege; Rudaz, Serge et al

Conference (2016, April)

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See detailAlpha-synuclein as biomarker in Parkinson’s disease: strategies for detection in CGE-LIF
Houbart, Virginie ULiege; Napp, Aurore ULiege; Rudaz, Serge et al

Poster (2016, April)

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See detailRapport de mission - MSB 2016
Houbart, Virginie ULiege

Report (2016)

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See detailImpact of injection solvent composition on protein identification incolumn-switching chip-liquid chromatography/mass spectrometry
Houbart, Virginie ULiege; COBRAIVILLE, Gaël ULiege; Nys, Gwenaël ULiege et al

in Journal of Chromatography. A (2016), 1445

In shotgun proteomics, the gold standard technique is reversed-phase liquid chromatography coupledto mass spectrometry. Many researches have been carried out to study the effects on identification per ... [more ▼]

In shotgun proteomics, the gold standard technique is reversed-phase liquid chromatography coupledto mass spectrometry. Many researches have been carried out to study the effects on identification per-formances of chromatographic parameters such as the stationary phase and column dimensions, mobilephase composition and flow rate, as well as the gradient slope and length. However, little attention isusually paid to the injection solvent composition.In this study, we investigated the effect of the injection solvent on protein identification parameters(number of distinct peptides, amino acid coverage and MS/MS search score) as well as sensitivity. Trypticpeptides from six different proteins, covering a wide range of physicochemical properties, were employedas training set. Design of experiments was employed as a tool to highlight the factors related to thecomposition of the injection solvent that significantly influenced the obtained results. Optimal resultsfor the training set were applied to analysis of more complex samples. The experiments pointed outoptimising the composition of the injection solvent had a strong beneficial effect on all the consideredresponses. On the basis of these results, an approach to determine optimal conditions was proposed tomaximise the protein identification performances and detection sensitivity. [less ▲]

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See detailHepcidin determination in dried blood by microfluidic LC-MS/MS: comparison of DBS and volumetric absorptive microsampling for matrix effect and recovery.
Houbart, Virginie ULiege; COBRAIVILLE, Gaël ULiege; Servais, Anne-Catherine ULiege et al

in Bioanalysis (2015), 7(21), 2789-99

BACKGROUND: Dried blood analysis experiences a growing interest due to practical, ethical and financial advantages compared with classical wet plasma or serum analysis. Besides classical DBS, new ... [more ▼]

BACKGROUND: Dried blood analysis experiences a growing interest due to practical, ethical and financial advantages compared with classical wet plasma or serum analysis. Besides classical DBS, new alternatives are commercialized as volumetric absorptive microsampling (VAMS) that are expected to overcome hematocrit influence. RESULTS: The feasibility of hepcidin (a peptide hormone) extraction and determination from DBS and VAMS blood sampling was investigated. Experimental design was used to determine the optimal extraction conditions. Matrix effect and extraction recovery were studied and a special attention was paid to phospholipid removal. CONCLUSION: The data suggest that the combination of VAMS and phospholipid removal plates provides low matrix effect and high sensitivity, and constitutes an easy and promising protocol for hepcidin analysis. [less ▲]

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See detailFluoxetine and norfluoxetine quantitation in rat serum by LC-chip-MS/MS
Houbart, Virginie ULiege; Charlier, Thierry; Pawluski, Jodi et al

Poster (2014, June)

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See detailQuantitation of hepcidin in dried blood spots by microfluidic LC-chip-MS/MS
Houbart, Virginie ULiege; Servais, Anne-Catherine ULiege; Fillet, Marianne ULiege

Conference (2014, June)

Microfluidic LC on a chip coupled to tandem mass spectrometry has been shown to be a sensitive tool for the quantitative analysis of small molecules and peptides. A major advantage of microfluidic ... [more ▼]

Microfluidic LC on a chip coupled to tandem mass spectrometry has been shown to be a sensitive tool for the quantitative analysis of small molecules and peptides. A major advantage of microfluidic separation techniques is the small requirements in terms of sample volume. This feature is particularly valuable for applications in the context of studies on small laboratory animals like rodents, or less-invasive clinical routine tests in patients, especially for paediatric applications. We previously developed a quantitation method for hepcidin, a peptide biomarker, in human plasma using µ-SPE (miniaturised solid-phase extraction) as sample preparation technique. The developed method allowed the quantitation of hepcidin using only 50 µL plasma with an excellent sensitivity. However, this efficient technique is quite expensive and time-consuming. To further reduce sample volume needs and simplify sample preparation, we developed a preparation method based on dried blood spot (DBS) analysis. In this case, a precise volume of blood (< 20 µL) is collected with a micro-capillary, dispensed on a paper card and dried. The obtained blood spot is then punched from the card, extracted in an appropriate solvent, and analysed by microfluidic LC-chip coupled to mass spectrometry. Method development was assisted by experimental design to optimise blood deposition and extraction conditions to ensure maximal analyte recovery while reducing interference co-extraction. Different ways of internal standard addition were also evaluated. In this study, the results obtained using µ-SPE and DBS are compared in terms of ease-of-use, throughput, sample requirements, cost, sensitivity and robustness. [less ▲]

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See detailFluoxetine dose and administration method differentially affect hippocampal plasticity in adult female rats.
Pawluski, Jodi L.; van Donkelaar, Eva; Abrams, Zipporah et al

in Neural Plasticity (2014), 2014

Selective serotonin reuptake inhibitor medications are one of the most common treatments for mood disorders. In humans, these medications are taken orally, usually once per day. Unfortunately ... [more ▼]

Selective serotonin reuptake inhibitor medications are one of the most common treatments for mood disorders. In humans, these medications are taken orally, usually once per day. Unfortunately, administration of antidepressant medications in rodent models is often through injection, oral gavage, or minipump implant, all relatively stressful procedures. The aim of the present study was to investigate how administration of the commonly used SSRI, fluoxetine, via a wafer cookie, compares to fluoxetine administration using an osmotic minipump, with regards to serum drug levels and hippocampal plasticity. For this experiment, adult female Sprague-Dawley rats were divided over the two administration methods: (1) cookie and (2) osmotic minipump and three fluoxetine treatment doses: 0, 5, or 10 mg/kg/day. Results show that a fluoxetine dose of 5 mg/kg/day, but not 10 mg/kg/day, results in comparable serum levels of fluoxetine and its active metabolite norfluoxetine between the two administration methods. Furthermore, minipump administration of fluoxetine resulted in higher levels of cell proliferation in the granule cell layer (GCL) at a 5 mg dose compared to a 10 mg dose. Synaptophysin expression in the GCL, but not CA3, was significantly lower after fluoxetine treatment, regardless of administration method. These data suggest that the administration method and dose of fluoxetine can differentially affect hippocampal plasticity in the adult female rat. [less ▲]

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See detailDéveloppement de méthodes de quantification en milieu complexe par chromatographie liquide microfluidique couplée à la spectrometrie de masse
Houbart, Virginie ULiege; Rozet, Eric ULiege; Crommen, Jacques ULiege et al

Conference (2013, June)

L’hepcidine est un biomarqueur peptidique dont l’intérêt tant comme outil de diagnostic que de suivi de pathologies est de plus en plus solidement établi. Il existe donc une demande forte d’outils ... [more ▼]

L’hepcidine est un biomarqueur peptidique dont l’intérêt tant comme outil de diagnostic que de suivi de pathologies est de plus en plus solidement établi. Il existe donc une demande forte d’outils sensibles et robustes afin de la doser au sein de milieux biologiques tels que le plasma ou le sérum. Une méthode analytique a été développée à l’aide d’un système chromatographique miniaturisé (nanoLC-chip) couplé à un spectromètre de masse permettant d’assurer un dosage de l’hepcidine à la fois sensible et fiable. Lors du développement de cette méthode, il a été constaté que la composition de l’échantillon avait une influence majeure sur la réponse analytique. Or, l’utilisation de systèmes chromatographiques miniaturisés implique souvent l’injection de volumes proportionnellement très importants par rapport aux dimensions du système, ce qui amplifie encore l’impact de sa composition. C’est pourquoi il est capital d’avoir une bonne compréhension des phénomènes qui ont lieu entre l’injection de l’échantillon dans le système chromatographique et la détection par spectrométrie de masse, et particulièrement lors du développement de méthodes analytiques quantitatives. Dans cette étude, nous avons utilisé la planification expérimentale afin de mieux comprendre le comportement chromatographique des peptides, ainsi que les facteurs qui influencent la sensibilité de la méthode développée. Un mélange de peptides a été sélectionné, varié tant du point de vue du poids moléculaire que du point isoélectrique et de l’hydropathie. Un plan de criblage a permis de délimiter le domaine expérimental ainsi que les facteurs significatifs parmi la composition de la phase mobile (proportion et nature de l’agent de paire d’ions) et de l’échantillon en lui-même (nature de l’agent de paire d’ions et proportion de solvant organique). Ensuite, un plan d’expériences factoriel complet a été mis en œuvre afin d’observer plus finement le rôle de chaque facteur ainsi que les interactions éventuelles qui les lient. Certains facteurs ont montré un effet très marqué tant sur l’intensité de la réponse que sur la rétention. Entre autres, la composition de l’échantillon, facteur parfois négligé lors du développement de méthodes, a démontré son importance capitale, en particulier sur les phénomènes de rétention des peptides. Les données obtenues ont également permis de dégager des conditions optimales d’analyse en termes de rétention et de sensibilité. Enfin, une analyse en composantes principales a également été réalisée sur le grand nombre de données récoltées dans le but de mettre en évidence d’éventuels propriétés physicochimiques des peptides qui pourraient avoir un impact significatif sur les réponses étudiées. [less ▲]

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See detailDevelopmental fluoxetine exposure normalizes the long-term effects of maternal stress on post-operative pain in Sprague-Dawley rat offspring.
Knaepen, Liesbeth; Rayen, Ine; Charlier, Thierry D. et al

in PLoS ONE (2013), 8(2), 57608

Early life events can significantly alter the development of the nociceptive circuit. In fact, clinical work has shown that maternal adversity, in the form of depression, and concomitant selective ... [more ▼]

Early life events can significantly alter the development of the nociceptive circuit. In fact, clinical work has shown that maternal adversity, in the form of depression, and concomitant selective serotonin reuptake inhibitor (SSRI) treatment influence nociception in infants. The combined effects of maternal adversity and SSRI exposure on offspring nociception may be due to their effects on the developing hypothalamic-pituitary-adrenal (HPA) system. Therefore, the present study investigated long-term effects of maternal adversity and/or SSRI medication use on nociception of adult Sprague-Dawley rat offspring, taking into account involvement of the HPA system. Dams were subject to stress during gestation and were treated with fluoxetine (2x/5 mg/kg/day) prior to parturition and throughout lactation. Four groups of adult male offspring were used: 1. Control+Vehicle, 2. Control+Fluoxetine, 3. Prenatal Stress+Vehicle, 4. Prenatal Stress+Fluoxetine. Results show that post-operative pain, measured as hypersensitivity to mechanical stimuli after hind paw incision, was decreased in adult offspring subject to prenatal stress alone and increased in offspring developmentally exposed to fluoxetine alone. Moreover, post-operative pain was normalized in prenatally stressed offspring exposed to fluoxetine. This was paralleled by a decrease in corticosteroid binding globulin (CBG) levels in prenatally stressed offspring and a normalization of serum CBG levels in prenatally stressed offspring developmentally exposed to fluoxetine. Thus, developmental fluoxetine exposure normalizes the long-term effects of maternal adversity on post-operative pain in offspring and these effects may be due, in part, to the involvement of the HPA system. [less ▲]

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