References of "Fillet, Marianne"
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See detailIdentification of protein biomarkers associated with cardiac ischemia by a proteomic approach.
Fillet, Marianne ULg; Deroyer, Céline ULg; COBRAIVILLE, G. et al

in Biomarkers : biochemical indicators of exposure, response, and susceptibility to chemicals (2013), 18(7), 614-24

Angina is chest pain induced by ischemia of the heart muscle, generally due to obstruction or spasm of the coronary arteries. People that suffer from average to severe cases of angina have an increased ... [more ▼]

Angina is chest pain induced by ischemia of the heart muscle, generally due to obstruction or spasm of the coronary arteries. People that suffer from average to severe cases of angina have an increased percentage of death before the age of 55, usually around 60%. Therefore, prevention of major complications, optimizing diagnosis, prognosis and therapeutics are of primary importance. The main objective of this study was to uncover biomarkers by comparing serum protein profiles of patients suffering from stable or unstable angina and controls. We identified by non-targeted proteomic approach and confirmed by the means of independent techniques, the differential expression of several proteins indicating significantly increased vascular inflammation response, disturbance in the lipid metabolism and in atherogenic plaques stability. [less ▲]

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See detailKinetics of IL-7 and IL-15 Levels after Allogeneic Peripheral Blood Stem Cell Transplantation following Nonmyeloablative Conditioning
De Bock, Muriel; Fillet, Marianne ULg; Hannon, Muriel ULg et al

in PLoS ONE (2013), 8(2), 55876

Background: We analysed kinetics of IL-7 and IL-15 levels in 70 patients given peripheral blood stem cells after nonmyeloablative conditioning. Methods: EDTA-anticoagulated plasma and serum samples were ... [more ▼]

Background: We analysed kinetics of IL-7 and IL-15 levels in 70 patients given peripheral blood stem cells after nonmyeloablative conditioning. Methods: EDTA-anticoagulated plasma and serum samples were obtained before conditioning and about once per week after transplantation until day 100. Samples were aliquoted and stored at 280uC within 3 hours after collection until measurement of cytokines. IL-7 and IL-15 levels were measured by ELISAs. Results: Median IL-7 plasma levels remained below 6 pg/L throughout the first 100 days, although IL-7 plasma levels were significantly higher on days 7 (5.1 pg/mL, P = 0.002), 14 (5.2 pg/mL, P,0.001), and 28 (5.1 pg/mL, P = 0.03) (but not thereafter) than before transplantation (median value of 3.8 pg/mL). Median IL-15 serum levels were significantly higher on days 7 (12.5 pg/mL, P,0.001), 14 (10.5 pg/mL, P,0.001), and 28 (6.2 pg/mL, P,0.001) than before transplantation (median value of 2.4 pg/mL). Importantly, IL-7 and IL-15 levels on days 7 or 14 after transplantation did not predict grade II–IV acute GVHD. Conclusions: These data suggest that IL-7 and IL-15 levels remain relatively low after nonmyeloablative transplantation, and that IL-7 and IL-15 levels early after nonmyeloablative transplantation do not predict for acute GVHD. [less ▲]

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See detailHigh inorganic triphosphatase activities in bacteria and mammalian cells: Identification of the enzymes involved.
Kohn, Grégory ULg; Delvaux, David ULg; Lakaye, Bernard ULg et al

in PLoS ONE (2012), 7(9), 43879

Background: We recently characterized a specific inorganic triphosphatase (PPPase) from Nitrosomonas europaea. This enzyme belongs to the CYTH superfamily of proteins. Many bacterial members of this ... [more ▼]

Background: We recently characterized a specific inorganic triphosphatase (PPPase) from Nitrosomonas europaea. This enzyme belongs to the CYTH superfamily of proteins. Many bacterial members of this family are annotated as predicted adenylate cyclases, because one of the founding members is CyaB adenylate cyclase from A. hydrophila. The aim of the present study is to determine whether other members of the CYTH protein family also have a PPPase activity, if there are PPPase activities in animal tissues and what enzymes are responsible for these activities. Methodology/Principal Findings: Recombinant enzymes were expressed and purified as GST- or His-tagged fusion proteins and the enzyme activities were determined by measuring the release of inorganic phosphate. We show that the hitherto uncharacterized E. coli CYTH protein ygiF is a specific PPPase, but it contributes only marginally to the total PPPase activity in this organism, where the main enzyme responsible for hydrolysis of inorganic triphosphate (PPPi) is inorganic pyrophosphatase. We further show that CyaB hydrolyzes PPPi but this activity is low compared to its adenylate cyclase activity. Finally we demonstrate a high PPPase activity in mammalian and quail tissue, particularly in the brain. We show that this activity is mainly due to Prune, an exopolyphosphatase overexpressed in metastatic tumors where it promotes cell motility. Conclusions and General Significance: We show for the first time that PPPase activities are widespread in bacteria and animals. We identified the enzymes responsible for these activities but we were unable to detect significant amounts of PPPi in E. coli or brain extracts using ion chromatography and capillary electrophoresis. The role of these enzymes may be to hydrolyze PPPi, which could be cytotoxic because of its high affinity for Ca2+, thereby interfering with Ca2+ signaling. [less ▲]

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See detailDevelopment of a generic micellar electrokinetic chromatography method for the separation of 15 antimalarial drugs as a tool to detect medicine counterfeiting
Lamalle, Caroline ULg; Marini Djang'Eing'A, Roland ULg; Debrus, Benjamin ULg et al

in Electrophoresis (2012), 33

Since antimalarial drugs counterfeiting is dramatically present on the African market, the development of simple analytical methods for their quality control is of great importance. This work consists in ... [more ▼]

Since antimalarial drugs counterfeiting is dramatically present on the African market, the development of simple analytical methods for their quality control is of great importance. This work consists in the CE analysis of 15 antimalarials (artesunate, artemether, amodiaquine, chloroquine, piperaquine, primaquine, quinine, cinchonine, mefloquine, halofantrine, sulfadoxine, sulfalen, atovaquone, proguanil, and pyrimethamine). Since all these molecules cannot be ionized at the same pH, MEKC was preferred because it also allows separation of neutral compounds. Preliminary experiments were first carried out to select the most crucial factors affecting the antimalarials separation. Several conditions were tested and four parameters as well as their investigation domain were chosen: pH (5–10), SDS concentration (20–90 mM), ACN proportion (10–40%), and temperature (20–35°C). Then, the experimental design methodology was used and a central composite design was selected. Mathematical modeling of the migration times allowed the prediction of optimal conditions (29°C, pH 6.6, 29 mM SDS, 36% ACN) regarding analyte separation. The prediction at this optimum was verified experimentally and led to the separation of 13 compounds within 8 min. Finally, the method was successfully applied to the quality control of African antimalarial medicines for their qualitative and quantitative content. [less ▲]

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See detailDERP6 (ELP5) and C3ORF75 (ELP6) regulate tumorigenicity and migration of melanoma cells as subunits of Elongator
Close, Pierre ULg; Gillard, Magali; Ladang, Aurélie ULg et al

in Journal of Biological Chemistry (2012)

The Elongator complex is composed of 6 subunits (Elp1-Elp6) and promotes RNAPII transcript elongation through histone acetylation in the nucleus as well as tRNA modification in the cytoplasm. This ... [more ▼]

The Elongator complex is composed of 6 subunits (Elp1-Elp6) and promotes RNAPII transcript elongation through histone acetylation in the nucleus as well as tRNA modification in the cytoplasm. This acetyltransferase complex directly or indirectly regulates numerous biological processes ranging from exocytosis and resistance to heat shock in yeast to cell migration and neuronal differentiation in higher eukaryotes. The identity of human ELP1 through ELP4 has been reported but human ELP5 and ELP6 have remained uncharacterized. Here, we report that DERP6 (ELP5) and C3ORF75 (ELP6) encode these subunits of human Elongator. We further investigated the importance and function of these two subunits by a combination of biochemical analysis and cellular assays. Our results show that DERP6/ELP5 is required for the integrity of Elongator and directly connects ELP3 to ELP4. Importantly, the migration and tumorigenicity of melanomaderived cells are significantly decreased upon Elongator depletion through ELP1 or ELP3. Strikingly, DERP6/ELP5 and C3ORF75/ELP6-depleted melanoma cells have similar defects, further supporting the idea that DERP6/ELP5 and C3ORF75/ELP6 are essential for Elongator function. Together, our data identify DERP6/ELP5 and C3ORF75/ELP6 as key players for migration, invasion and tumorigenicity of melanoma cells, as integral subunits of Elongator. [less ▲]

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See detailRace cycling: biological evolution
LE GOFF, Caroline ULg; Kaux, Jean-François ULg; Goffaux, Sébastien et al

in Meeusen, R; Duchateau, J; Roelands, B (Eds.) et al Book of Abstracts of the 17th annual Congress of the ECSS (2012, July)

Introduction: The metabolic and cardiac impact of a cycling effort on blood biology is not very well described in the literature. We aimed to measure the concentration of different biomarkers (cardiac and ... [more ▼]

Introduction: The metabolic and cardiac impact of a cycling effort on blood biology is not very well described in the literature. We aimed to measure the concentration of different biomarkers (cardiac and metabolic) released during an international cycling race. Materials and methods: Venous blood samples of 15 young men (25.1 ± 6.4 y.o.) were collected just before (T1), just after (T2), 3 hours (T3) after an international cycling race of 179.6 kilometers in Belgium for the determination of cardiac and metabolic biomarkers: red blood cell (RBC), haemoglobin (HgB), creatinin (Cr), highly sensitive troponin T (hsTnT), myoglobin (MYO) and NT-proBNP. All automated assays were performed according to the manufacter’s specifications. For the statistical analysis, an Anova calculated with the Statistica Software version 9.1 was used. Results and discussions: RBC and HgB levels varied significantly between T0 and T3 (respectively p=0.0026, and p=0.002). Cr concentration also varied significantly between all times (T0-T1:p<0.0001, T1-T3:p=0.0326 and T0-T3 p=0.0001). These changes might be related to renal flow depletion during exercice. MYO increased significantly between T0 and T1 (p<0.0001), but quickly decreased between T1 and T3, however the T3 level stay higher than T0 (p=0.014). The stress delivered from the physical activity performed during the race induced a significant variation of hsTnT which increased significantly between T0 and T1 (p<0.0001) and stayed higher 3 hours after the end of the exercise (T0-T3: p<0.0001). The intense exercise delivery by the race induced a significant variation of NT-proBNP, that followed the same kinetic of hsTnT but in smaller proportion. We noticed variations statistically significant between T0 and T1 and between T0 and T3 for NT-proBNP. These increases of cardiac biomarkers were significant but reasonable and could not allow us to talk about cellular necrosis or irreversible injury. Conclusion: Our results show that stress generated by a cycling race could be the cause for the different metabolic variations observed. Troponin T stays without a doubt the most specific marker for stress related to myocardial tissue. Its increase can then be considered as being of interest. [less ▲]

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See detailImpact of strenous exercise on the release of cardiac biomarkers
LE GOFF, Caroline ULg; MELON, Pierre ULg; Kaux, Jean-François ULg et al

in Meeusen, R; Duchateau, J; Roelands, B (Eds.) et al Book of Abstracts of the 17th annual Congress of the ECSS (2012, July)

Background: Cardiac troponins (cTn) are considered as the best biomarkers for detection of myocardial cell injury and NT-proBNP as the best for the cardiac insufficiency. In this study, cTnT was measured ... [more ▼]

Background: Cardiac troponins (cTn) are considered as the best biomarkers for detection of myocardial cell injury and NT-proBNP as the best for the cardiac insufficiency. In this study, cTnT was measured by new commercially available high-sensitive methods in subjects undergoing the Maasmarathon. Our aim was to compare cTnT and NT-proBNP levels in sportive subjects before and after a strenuous exercise. Materials and Methods: Twenty eight subjects (26 ♂, 42.5±11yo) underwent a race of 42.195 kilometers between Visé (Belgium) and Maastricht (The Netherlands). We drowned blood samples before (T0), just after (T1) and three hours after the race (T3). For all patients, cTnT concentrations were measured by high sensitive methods (hsTnT, Roche Diagnostics) on heparin plasma. The NT-proBNP was also determined with the kit Roche on heparin plasma. The protocol was approved by the ethics committee of the University of Liège (Belgium). All subjects gave their informed consent. All statistical analyses were performed using Medcalc version 8.1 for Windows. p-value <0.01 was regarded as statistically significant. Results and discussion: A significant difference between hsTnT concentrations at T0 and T1 (p<0.0001) was measured as well as between T0 and T3 (p<0.001) for NT-proBNP, but not between T1 and T3. This observation appeared only after a strenuous exercise but today this type of exercise is not reproduce easier in a laboratory of sport. Moreover, at this moment, nobody knows if these observations would have cardiac consequences at long terms. Conclusions: Measurement of cardiac troponins by high sensitive methods allows detecting significant release of biomarkers from the heart during exercise. The levels of NT-proBNP were found significantly increased but in less extent than TnThs. We think that the TnThs could be an interesting marker in the future to help sport medicine to detect risk of developing a cardiac problem. [less ▲]

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See detailAn ESR, Mass Spectrometry and Fluorescence microscopy approach to study the stearic acid derivatives anchoring in cells
Grammenos, Angeliki ULg; Fillet, Marianne ULg; Collodoro, Mike et al

in Applied Magnetic Resonance (2012)

Lateral phase separations in biological membranes are of great interest, making Electron Spin Resonance (ESR) spectroscopy combined with spin labelling a non destructive and sensitive technique for the ... [more ▼]

Lateral phase separations in biological membranes are of great interest, making Electron Spin Resonance (ESR) spectroscopy combined with spin labelling a non destructive and sensitive technique for the study of lipid rafts. This is currently accepted that spin probe localization is on the plasma membrane. However, no study confirms this hypothesis. Herein, we report, for the first time, an accurate multi spectral method for the quantification of lipid spin label presence in every sub-cellular fraction. Cells were incubated with 5-doxyl stearic acid derivative and then sub-fractionated. Results of our multimodal spectroscopy approach ubiquitously demonstrate that the presence of ESR spin label only sets in the plasma membranes. [less ▲]

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See detailBiological variations during a race cycling
LE GOFF, Caroline ULg; Kaux, Jean-François ULg; Goffaux, Sébastien et al

in Biomedica 2012 (2012, April)

Background: The metabolic and cardiac impact of a cycling effort on blood biology is not very well described in the literature. We aimed to measure the concentration of different biomarkers (cardiac and ... [more ▼]

Background: The metabolic and cardiac impact of a cycling effort on blood biology is not very well described in the literature. We aimed to measure the concentration of different biomarkers (cardiac and metabolic) released during an international cycling race. Materials and Methods: Venous blood samples of 15 young men (25.1 ± 6.4 y.o.) were collected just before (T1), just after (T2), 3 hours (T3) after an international cycling race of 176 kilometers in Belgium for the determination of cardiac and metabolic biomarkers: red blood cells (RBC) haemoglobin (HgB) creatinin (Cr) highly sensitive troponin T (hsTnT) myoglobin (MYO) NT-proBNP All automated assays were performed according to the manufacter’s specifications. For the statistical analysis, an Anova calculated with the Statistica Software version 9.1 was used. Results: •RBC and HgB levels varied significantly between T0 and T3 (respectively p=0.0026, and p=0.002) (Fig. 1 and 2). • Cr concentration also varied significantly between all times (T0-T1:p<0.0001, T1-T3:p=0.0326 and T0-T3 p=0.0001)(Fig.3). These changes might be related to renal flow depletion during exercise. •MYO increased significantly between T0 and T1 (p<0.0001), but quickly decreased between T1 and T3, however the T3 level stay higher than T0 (p=0.014) (Fig.4). •The stress delivered from the physical activity performed during the race induced a significant variation of hsTnT which increased significantly between T0 and T1 (p<0.0001) and stayed higher 3 hours after the end of the exercise (T0-T3: p<0.0001) (Fig.5) . •The intense exercise delivery by the race induced a significant variation of NT-proBNP, that followed the same kinetic of hsTnT but in smaller proportion. We noticed variations statistically significant between T0 and T1 and between T0 and T3 for NT-proBNP (Fig.6). •These increases of cardiac biomarkers were significant but reasonable and could not allow us to talk about cellular necrosis or irreversible injury. Conclusions: Our results show that stress generated by a cycling race could be the cause for the different metabolic variations observed. Troponin T stays without a doubt the most specific marker for stress related to myocardial tissue. Its increase can then be considered as being of interest. [less ▲]

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See detailThe c-jun N-terminal Kinase (JNK)-binding Protein (JNKBP1) Acts as a Negative Regulator of NOD2 Protein Signaling by Inhibiting Its Oligomerization Process
Lecat, Aurore ULg; Di Valentin, Emmanuel ULg; Somja, Joan ULg et al

in Journal of Biological Chemistry (2012), 287(35), 29213-26

NOD2 is one of the best characterized member of the cytosolic NOD-like receptors (NLR) family. NOD2 is able to sense muramyl dipeptide (MDP), a specific bacterial cell wall component, and to subsequently ... [more ▼]

NOD2 is one of the best characterized member of the cytosolic NOD-like receptors (NLR) family. NOD2 is able to sense muramyl dipeptide (MDP), a specific bacterial cell wall component, and to subsequently induce various signalling pathways leading to NF- kappaB activation and autophagy, both events contributing to an efficient innate and adaptative immune response. Interestingly, loss-of-function nod2 variants were associated with a higher susceptibility for Crohn ' s disease (CD), which highlights the physiological importance of proper regulation of NOD2 activity. We performed a biochemical screen to search for new NOD2 regulators. We identified a new NOD2 partner, c-jun N-terminal kinase binding protein 1 (JNKBP1), a scaffold protein characterized by a N-terminal WD-40 domain. JNKBP1, through its WD-40 domain, binds to NOD2 following MDP activation. This interaction attenuates NOD2-mediated NF-kappaB activation and IL-8 secretion as well as NOD2 antibacterial activity. JNKBP1 exerts its repressor effect by disturbing NOD2 oligomerization and RIP2 tyrosine phosphorylation, both steps required for downstream NOD2 signalling. We furthermore showed that JNKBP1 and NOD2 are co-expressed in the human intestinal epithelium and immune cells recruited in the lamina propria, which suggests that JNKBP1 contributes to maintain NOD2-mediated intestinal immune homeostasis. [less ▲]

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See detailPrincipes toxiques, toxicité et technologie de détoxification de la graine de Jatropha curcas L. (synthèse bibliographique)
Nesseim, Thierry Daniel Tamsir; Fillet, Marianne ULg; Mergeai, Guy ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(4), 531-540

The use of meal from the crushing of Jatropha curcas seed for livestock feed is limited owing to the variable amounts of seed available. This availability depends on the level and variety of toxic and ... [more ▼]

The use of meal from the crushing of Jatropha curcas seed for livestock feed is limited owing to the variable amounts of seed available. This availability depends on the level and variety of toxic and antinutritional compounds contained in the seed at a given time; the most important of these compounds are phorbol esters and curcin. The phorbol esters present in J. curcas seed are euphorbiaceae diterpenes, known for their inflammatory action resulting in irritation and toxicity to insects, fish and mammals. These compounds are sometimes completely degraded in soil and they may be reduced by physical, chemical or biological processes, with a reduction ratio of between 50 and 95%. Curcin is an irritating toxalbumin with lectin activity; it is inactivated by heat treatment at 121 °C for 30 min. Other antinutritional compounds are also present in J. curcas seed, such as saponins and an inhibitor of trypsin activity. This trypsin-inhibiting compound interferes with the digestion process and its reduction is achieved through thermal, chemical or biological treatments. The elimination of, or at least a reduction in the levels of, these molecules represents a rerequisite for using J. curcas meal in the livestock feed sector. [less ▲]

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See detailOptimization of the liquid chromatography enantioseparation of chiral acidic compounds using cellulose tris(3-chloro-4-methylphenylcarbamate) as chiral selector and polar organic mobile phases.
Dossou, K. S. S.; Farcas, Elena ULg; Servais, Anne-Catherine ULg et al

in Journal of Chromatography. A (2012), 1234

The LC enantioseparation of chiral acidic and zwitterionic drugs selected as model compounds was optimized using chlorine containing cellulose based chiral stationary phases and polar organic mobile ... [more ▼]

The LC enantioseparation of chiral acidic and zwitterionic drugs selected as model compounds was optimized using chlorine containing cellulose based chiral stationary phases and polar organic mobile phases. The main solvent of the mobile phase was acetonitrile, the temperature was settled at 25 degrees C and a stationary phase with cellulose tris(3-chloro-4-methylphenylcarbamate) as chiral selector (3-Cl-4-Me-PC) was selected. In the screening step, the nature and concentration of both acidic and basic additives were found to have a significant effect on retention, selectivity and resolution. Acetic acid (AcA) was selected as acidic additive for the optimization step since it could lead to the enantioseparation of more acidic compounds than trifluoroacetic acid (TFA) and formic acid (FA), while among the three basic additives tested, diethylamine (DEA) most often gave better results with respect to enantioresolution and selectivity than butylamine (BuA) and triethylamine (TEA). The optimization was performed using a central composite face-centered design with two factors, namely the concentration of acetic acid (0.1-0.3%) and the concentration of DEA (0.01-0.1%) in the mobile phase. On the basis of the results obtained in the screening and optimization steps, a strategy for the rapid development of methods for the enantioseparation of acidic or neutral compounds was proposed. [less ▲]

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See detailCombination of capillary electrophoresis, molecular modelling and nuclear magnetic resonance to study the interaction mechanisms between single-isomer anionic cyclodextrin derivatives and basic drug enantiomers in a methanolic background electrolyte.
Servais, Anne-Catherine ULg; Rousseau, Anne; Dive, Georges ULg et al

in Journal of Chromatography. A (2012), 1232

In order to improve our knowledge of the mechanisms of enantiomer recognition pattern in nonaqueous systems, an approach combining nonaqueous CE (NACE), molecular modelling and NMR was undertaken ... [more ▼]

In order to improve our knowledge of the mechanisms of enantiomer recognition pattern in nonaqueous systems, an approach combining nonaqueous CE (NACE), molecular modelling and NMR was undertaken. Bupivacaine and propranolol were selected as model compounds and their interactions with two single-isomer highly charged beta-CD derivatives, namely heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-CD (HDMS-beta-CD) and heptakis(2,3-di-O-acetyl-6-O-sulfo)-beta-CD (HDAS-beta-CD), were studied. The CD-bupivacaine complexes were evaluated by 2-D Rotating-frame Overhauser Effect SpectroscopY (ROESY) experiments. From these experiments, it can be assumed that inclusion complexes are not formed, whatever the CD derivative used. Molecular modelling was performed at the RHF/MINI-1 or B3LYP/6-31G(d) level. External as well as inclusion type complexes with the alkyl chain of propranolol into both CD cavities were located. Interaction energies calculated for bupivacaine and propranolol correlated with the enantiomer migration order observed in the NACE experiments using both anionic CD derivatives. The interaction of propranolol with HDMS-beta-CD or HDAS-beta-CD gives rise to a family of external and inclusion complexes in which some are more probably obtained. [less ▲]

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See detailComparative enantioseparation of talinolol in aqueous and non-aqueous capillary electrophoresis and study of related selector-selectand interactions by nuclear magnetic resonance spectroscopy.
Chankvetadze, Lali; Servais, Anne-Catherine ULg; Fillet, Marianne ULg et al

in Journal of Chromatography. A (2012)

The enantiomers of the chiral beta-blocker drug talinolol were separated with two single component sulfated beta-cyclodextrin (CD) derivatives, namely heptakis (2,3-di-O-methyl-6-sulfo)-beta-CD) (HDMS ... [more ▼]

The enantiomers of the chiral beta-blocker drug talinolol were separated with two single component sulfated beta-cyclodextrin (CD) derivatives, namely heptakis (2,3-di-O-methyl-6-sulfo)-beta-CD) (HDMS-beta-CD) and heptakis (2,3-di-O-acetyl-6-sulfo)-beta-CD) (HDAS-beta-CD), in aqueous and non-aqueous capillary electrophoresis (CE). The enantiomer affinity pattern of talinolol toward these two CDs was opposite in both aqueous and non-aqueous CE. However, the enantiomer affinity pattern for a given CD derivative did not change when aqueous buffer was replaced with non-aqueous background electrolyte. The structures of the analyte-selector complexes in both, aqueous and non-aqueous electrolytes were studied using rotating frame nuclear Overhauser effect (ROESY) NMR spectroscopy. Inclusion complex formation between the enantiomers of talinolol and HDAS-beta-CD was confirmed in aqueous buffer, while the complex between the enantiomers of talinolol and HDMS-beta-CD was of the external type. The complex of the talinolol enantiomers with HDAS-beta-CD in non-aqueous electrolyte was also of the external type. In spite of external complex formation excellent separation of the enantiomers was observed in non-aqueous CE. [less ▲]

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See detailChemo- and enantio-selective method for the analysis of amino acids by capillary electrophoresis with in-capillary derivatization.
Fradi, Ines ULg; Servais, Anne-Catherine ULg; Lamalle, Caroline ULg et al

in Journal of Chromatography. A (2012)

A novel dual chiral CE method was developed for the separation of l- and d-amino acids (AAs), using in-capillary derivatization with 9-fluoroenylmethyl chloroformate (FMOC). Firstly, using pre-column ... [more ▼]

A novel dual chiral CE method was developed for the separation of l- and d-amino acids (AAs), using in-capillary derivatization with 9-fluoroenylmethyl chloroformate (FMOC). Firstly, using pre-column derivatization, the enantioseparation of FMOC-AAs was optimized according to the nature of cyclodextrins (CD). A background electrolyte (BGE) composed of 30mM beta-CD, 30mM octakis(2,3-dihydroxy-6-O-sulfo)-gamma-CD (OS-gamma-CD), 40mM tetraborate and 15% isopropanol (IPA) was selected and led to 17 baseline resolved pairs (R(s)=1.7-5.8) and two partially resolved pairs (Lys, R(s)=0.5 and Arg, R(s)=1.2). Experimental conditions for in-capillary derivatization were then optimized. Several parameters, such as mixing voltage and time, concentration of labeling solution and the length of the spacer plug were studied. The optimal conditions for in-capillary derivatization procedure were obtained using successive hydrodynamic injections (30mbar) of AAs for 2s, borate buffer for 4s and 10mM FMOC solution for 6s, followed by a mixing at 3kV for 72s and wait time of 1min. Moreover, a particular attention was paid to improve separation chemoselectivity. The effect on stereoselectivity and chemoselectivity of different factors, such as decrease of pH and tetraborate concentration and the addition of sodium dodecyl sulfate (SDS), was investigated using the in-capillary derivatization procedure. The best separation of a standard mixture of ten AA racemates was observed using a BGE containing 30mM beta-CD, 30mM OS-gamma-CD, 25mM SDS, 40mM sodium tetraborate and 17% IPA. [less ▲]

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