References of "Van Heugen, Jean-Claude"
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See detailIdentification and structure elucidation of four cannabimimetic compounds in seized products
Denooz, Raphaël ULg; VAN HEUGEN, Jean-Claude ULg; Frederich, Michel ULg et al

in Journal of Analytical Toxicology (2013), 37(2), 56-63

Since 2008, herbal mixtures with synthetic cannabinoid compounds have been sold as incense throughout the world. Although these new drugs are labeled as not for human consumption, these products are ... [more ▼]

Since 2008, herbal mixtures with synthetic cannabinoid compounds have been sold as incense throughout the world. Although these new drugs are labeled as not for human consumption, these products are smoked for their cannabis-like effects. This study reports the structural and spectral elucidation of four cannabimimetic compounds seized in Belgium: (4-methoxyphenyl)-1-(pentyl-1H-indol-3-yl)methanone (RCS-4), 1-(5-fluoropentyl)-3-(1-naphtoyl)indole (AM-2201), 2-(2-chlorophenyl)-1-(1-pentylindol-3-yl)ethanone (JWH-203) and 4-ethylnaphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-210). Laboratory investigations were conducted by liquid chromatography (LC)–ultraviolet spectroscopy, high-resolution accurate mass detection and nuclear magnetic resonance (NMR) analysis. This combined analytical approach allowed the detection of illicit compounds for which reference materials were not available. To facilitate identification and to complete existing databases, ultraviolet spectra and NMR data of all seized products are presented. Additionally, LC–quadrupole time-of-flight data were recorded to provide absolute identification. [less ▲]

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See detailTriphenylphosphonium salts of 1,2,4-benzothiadiazine 1,1-dioxides related to diazoxide targeting mitochondrial ATP-sensitive potassium channels
Constant-Urban, C.; Charif, M.; Goffin, Eric ULg et al

in Bioorganic & Medicinal Chemistry Letters (2013), 23

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See detailCurcumin-cyclodextrin complexes potentiate gemcitabine effects in an orthotopic mouse model of lung cancer.
Rocks, Natacha ULg; Bekaert, Sandrine ULg; Coia, I et al

in British Journal of Cancer (2012), 107(7), 1083-92

Background:Overall clinical outcome for advanced lung cancer remains very disappointing despite recent advances in treatment. Curcumin has been reported as potentially active against cancer.Methods:Owing ... [more ▼]

Background:Overall clinical outcome for advanced lung cancer remains very disappointing despite recent advances in treatment. Curcumin has been reported as potentially active against cancer.Methods:Owing to poor curcumin solubility, we have used cyclodextrins (CD) as an excipient allowing a considerable increase of aqueous solubility and bioavailability of curcumin. The effects of solubilised curcumin have been evaluated in cell cultures as well as in an in vivo orthotopic lung tumour mouse model.Results:Cell proliferation was reduced while apoptosis rates were increased when lung epithelial tumour cells were cultured in the presence of curcumin-CD complexes. For in vivo experiments, cells were grafted into lungs of C57Bl/6 mice treated by an oral administration of a non-soluble form of curcumin, CDs alone or curcumin-CD complexes, combined or not with gemcitabine. The size of orthotopically implanted lung tumours was reduced upon curcumin complex administration as compared with treatments with placebo or non-solubilised curcumin. Moreover, curcumin potentiated the gemcitabine-mediated antitumour effects.Conclusion:Our data demonstrate that curcumin, when given orally in a CD-solubilised form, reduces lung tumour size in vivo. In vitro experiments show impaired tumour cell proliferation and increased cell apoptosis. Moreover, our data underline a potential additive effect of curcumin with gemcitabine thus providing an efficient therapeutic option for antilung cancer therapy. [less ▲]

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See detailCoupling of Liquid Chromatography/Tandem Mass Spectrometry and Liquid Chromatography/Solid-Phase Extraction/NMR Techniques for the Structural Identification of Metabolites following In Vitro Biotransformation of SUR1-Selective ATP-Sensitive Potassium Channel Openers
Gillotin, F.; Chiap, Patrice ULg; Frederich, Michel ULg et al

in Drug Metabolism and Disposition : The Biological Fate of Chemicals (2010), 38(2), 232-240

SUR1-selective ATP-sensitive potassium channel openers (PCOs) have been shown to be of clinical value for the treatment of several metabolic disorders, including type I and type II diabetes, obesity and ... [more ▼]

SUR1-selective ATP-sensitive potassium channel openers (PCOs) have been shown to be of clinical value for the treatment of several metabolic disorders, including type I and type II diabetes, obesity and hyperinsulinemia. Taking into account these promising therapeutic benefits, different series of 3-alkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides structurally related to diazoxide were developed. In view of the lead optimisation process of the series, knowledge of ADMET parameters, and more particularly the metabolic fate of these compounds, is a fundamental requirement. For such a purpose, two selected promising compounds (BPDZ 73 and BPDZ 157) were incubated in the presence of phenobarbital-induced rat liver microsomes to produce expected mammal in vivo phase I metabolites. The resulting major metabolites were then analysed by both MS and NMR in order to completely elucidate their chemical structures. The two compounds were also further incubated in the presence of non-treated rats and human microsomes in order to compare the metabolic profiles. In the present study, the combined use of an exact mass LC-MS/MS platform and a LC-SPE-NMR system allowed the clarification of some unresolved structural assessments in the accurate chemical structure elucidation process of the selected PCOs drugs. These results greatly help the optimization of the lead compounds. [less ▲]

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See detailNew Fluorinated 1,2,4-Benzothiadiazine 1,1-Dioxides: Discovery of an Orally Active Cognitive Enhancer Acting through Potentiation of the 2-Amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic Acid Receptors
Francotte, Pierre ULg; Goffin, Eric ULg; Fraikin, Pierre ULg et al

in Journal of Medicinal Chemistry (2010), 53

In the search of a potent cognitive enhancer, a series of 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides have been synthesized and evaluated as positive allosteric modulators of the AMPA receptors. In ... [more ▼]

In the search of a potent cognitive enhancer, a series of 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides have been synthesized and evaluated as positive allosteric modulators of the AMPA receptors. In the present work, we focused our efforts on the insertion of mono- or polyfluoro- substituted alkyl chains at the 4-position of the thiadiazine ring in an attempt to enhance the pharmacokinetic behavior of previously described compounds. Among all the described compounds, 7-chloro-4-(2-fluoroethyl)-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide, 12b, was shown to exert a strong activity on AMPA receptors in vitro and a marked cognitive-enhancing effect in vivo after oral administration to Wistar rats. Considering its in vivo activity, the metabolic degradation of 12b was studied and compared to that of its nonfluorinated analogue 9b. Taken together, results of this study clearly validated the positive impact of the fluorine atom on the alkyl chain at the 4-position of benzothiadiazine dioxides on activity and metabolic stability. [less ▲]

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See detailPre-study and in-study validation of an ultra-high pressure LC method coupled to tandem mass spectrometry for off-line determination of oxytetracycline in nasal secretions of healthy pigs.
Bimazubute, Marcel Aimé ULg; Rozet, Eric ULg; Dizier, Isabelle ULg et al

in Journal of Chromatography. B : Analytical Technologies in the Biomedical & Life Sciences (2009), 877(23), 2349-57

In order to quantify oxytetracycline (OTC) in nasal secretions of healthy pigs after intramuscular injection of OTC at doses of 10, 20 and 40 mg/kg bodyweight, an original method based on ultra-high ... [more ▼]

In order to quantify oxytetracycline (OTC) in nasal secretions of healthy pigs after intramuscular injection of OTC at doses of 10, 20 and 40 mg/kg bodyweight, an original method based on ultra-high pressure liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) was developed and fully validated. Sample preparation consisted in protein precipitation preceded by the addition of a releasing protein reagent. Metacycline (MTC) was used as internal standard. Separation was carried out at 65 degrees C in the gradient elution mode on a short analytical column filled with Acquity BEH C(18) stationary phase. The mobile phase consisted in a mixture of water and acetonitrile containing 1 mM of oxalic acid and 0.1% (v/v) of formic acid. The triple quadrupole mass spectrometer operated in the positive electrospray ionization mode; OTC and MTC were detected using multiple reaction monitoring. The pre-study and in-study validation of this bioanalytical method was performed by applying a novel strategy based on total measurement error and accuracy profiles. The maximum risk of observing future measurements falling outside the acceptance limits during routine as well as the measurements uncertainty were also estimated. [less ▲]

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See detailLC/MS/NMR analysis of isomeric divanilloylquinic acids from the root bark of Fagara zanthoxyloides Lam
Ouattara, Badiore; Angenot, Luc ULg; Guissou, Pierre et al

in Phytochemistry (2004), 65(8), 1145-1151

Gradient HPLC coupled to DAD/UV, MS/MS and NMR has been applied to the rapid structure determination of three new isomeric divanilloylquinic acids from Fagara zanthoxyloides collected in Burkina Faso: 3,4 ... [more ▼]

Gradient HPLC coupled to DAD/UV, MS/MS and NMR has been applied to the rapid structure determination of three new isomeric divanilloylquinic acids from Fagara zanthoxyloides collected in Burkina Faso: 3,4-O-divanilloylquinic acid, 3,5-O-divanilloylquinic acid and 4,5-O-divanilloylquinic acid. Furthermore these new compounds named burkinabins A-C could play a useful role in sickle cell disease, as the active agents of Fagara zanthoxyloides are said to be unidentified aromatic compounds with carboxylic acid grouping (Adesanya, S.A., Sofowora, A., 1983. Biological standardisation of Zanthoxylum roots for antisickling activity. Planta Med. 48, 27-33). (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

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See detailSeparation, identification and quantitation of ceramides in human cancer cells by liquid chromatography–electrospray ionization tandem mass spectrometry
Fillet, Marianne ULg; Van Heugen, Jean-Claude ULg; Servais, Anne-Catherine ULg et al

in Journal of Chromatography. A (2002), 949

Ceramides are important intracellular second messengers that play a role in the regulation of cell growth, differentiation and programmed cell death. Qualitative and quantitative analysis of these second ... [more ▼]

Ceramides are important intracellular second messengers that play a role in the regulation of cell growth, differentiation and programmed cell death. Qualitative and quantitative analysis of these second messengers requires sensitive and specific analytical methods to detect endogenous levels of individual ceramide species and to differentiate between them. Nine synthetic ceramides were separated by liquid chromatography coupled to tandem mass spectrometry on a C bonded silica 18 column. The lipids were eluted in gradient elution mode using a mixture of water, acetonitrile and 2-propanol as mobile phase. They were detected by reaction monitoring performed on positive ion electrospray generated ions. Collision-induced fragmentations conducted on ceramides produced a well characteristic product ion at m/z 264, making multiple reaction monitoring (MRM) well suited for various ceramides quantitative measurements. After optimization of the extraction step, the proposed methodology was able to identify and quantify different ceramide species issued from human cancer cells. The method could be validated for C , C and C ceramides, quantified at the nanogram level. The validation exhibits good 16 18 20 results with respect to linearity, accuracy and precision. [less ▲]

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See detailInfluence of moderate temperatures on myristoyl-CoA metabolism and acyl-CoA thioesterase activity in the psychrophilic antarctic yeast Rhodotorula aurantiaca.
Sabri, Ahmed ULg; Bare, G.; Jacques, Philippe ULg et al

in Journal of Biological Chemistry (2001), 276(16), 12691-6

The inability of psychrophilic microorganisms to grow at moderate temperatures (>20 degrees C) presently represents an unresolved thermodynamic paradox. Here we report for the psychrophilic yeast ... [more ▼]

The inability of psychrophilic microorganisms to grow at moderate temperatures (>20 degrees C) presently represents an unresolved thermodynamic paradox. Here we report for the psychrophilic yeast Rhodotorula aurantiaca A19, isolated from Antarctic ice, that the inability to grow at temperatures close to 20 degrees C is associated with profound alterations in cell morphology and integrity. High performance liquid chromatography analysis of the intracellular acyl-CoA esters revealed an abnormal accumulation of myristoyl-CoA (C14-CoA) in cells cultivated close to the nonpermissive temperature. Its concentration (500 microm) was found to be 28-fold higher than in cells cultivated at 0 degrees C. If one considers its ability to disrupt membrane bilayers and to inhibit many cellular enzymes and functions, intracellular myristoyl-CoA accumulation in the psychrophile R. aurantiaca represents one of the principal causes of growth arrest at moderate temperatures. Intracellular acyl-CoA concentrations are believed to be regulated by thioesterase activity. Thus in an attempt to explore the mechanism by which temperature disrupts myristoyl-CoA metabolism, we isolated and characterized a long chain acyl-CoA thioesterase. The monomeric 80-kDa thioesterase from the psychrophilic yeast shows a very strong specificity for myristoyl-CoA. The affinity for substrate and the catalytic efficiency of the thioesterase are optimal below 5 degrees C (temperatures habitually experienced by the strain) and dramatically decrease with increasing temperature. The loss of affinity for substrate is related to the intracellular increase of myristoyl-CoA concentration. Our observations reveal one of the probable mechanisms by which temperature fixes the limit of growth for this psychrophilic yeast. [less ▲]

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