References of "Mouithys-Mickalad, Ange"
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See detailEffect of benzoic acid analogs on myeloperoxidase activity measured by a new technique to study their direct interaction with the enzyme.
Franck, Thierry ULg; Mazloum, Ali; Mouithys-Mickalad, Ange ULg et al

Poster (2011, May)

Myeloperoxidase (MPO) plays a key role in inflammatory response and constitutes a target for new drug development. The effects of some benzoic acid analogs were studied on the specific activity of human ... [more ▼]

Myeloperoxidase (MPO) plays a key role in inflammatory response and constitutes a target for new drug development. The effects of some benzoic acid analogs were studied on the specific activity of human MPO measured by SIEFED (“Specific Immunologic Extraction Followed by Enzymatic Detection”), an original method that consists of incubation of the compound with MPO, followed by capture of the enzyme by specific antibodies, washing (elimination of the compounds) and enzymatic detection of the immunocaptured enzyme. The compounds tested at 10-4, 10-5 and 10-6 M were studied in terms of structure activity relationship. Gallic acid (3,4,5-trihydroxybenzoic acid) with 3 hydroxyl groups had an important dose dependent inhibitory effect on MPO activity. Other molecules with less or without hydroxyl groups [3,4-dihydroxybenzoic acid, 2-hydroxybenzoic acid (salicylic acid) and benzoic acid] had rather an activator effect at 10-5 and 10-6 M. 2,4,6-Trihydroxybenzoic acid, with two hydroxyl groups adjacent to the carboxyl group, had a less efficient inhibitory effect. Caffeic acid (3,4-dihydroxycinnamic acid) with a propenoic acid group presented a dose dependent inhibitory effect on MPO activity contrary to its analog 3,4-dihydroxybenzoic acid. The esterification of the carboxyl group of gallic acid to obtain propyl gallate induced an activation of MPO at 10-5 and 10-6 M. Finally, the substitution of one or two hydroxyl groups by methoxyl ones (ferulic and syringic acids) decreased the efficiency of the molecules on the enzyme inhibition. The SIEFED technique appears as an innovative pharmacological tool to study the direct interaction of compounds with MPO. Number and position of hydroxyl groups and the extension of the carboxyl group of benzoic acid play a crucial role in the inhibition of MPO activity probably by facilitating the interaction with the active site or another elements of the enzyme structure. [less ▲]

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See detailModulating effects of acepromazine on the reactive oxygen species production by stimulated equine neutrophils
Sandersen, Charlotte ULg; Mouithys-Mickalad, Ange ULg; de la Rebière de Pouyade, Geoffroy ULg et al

in Veterinary Anaesthesia & Analgesia (2011), 38

To investigate the effect of acepromazine (ACP) on reactive oxygen species (ROS) production by stimulated equine neutrophils.

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See detailProduction of free radicals and oxygen consumption by primary equine endothelial cells during anoxia-reoxygenation.
de la Rebière de Pouyade, Geoffroy ULg; Salciccia, Alexandra ULg; Ceusters, Justine ULg et al

in Open Biochemistry Journal (The) (2011), 5

The endothelium plays an active role in ischemia/reperfusion injuries. Herein, we report the effect of a single or successive cycles of anoxia/reoxygenation (A/R) on the mitochondrial respiratory function ... [more ▼]

The endothelium plays an active role in ischemia/reperfusion injuries. Herein, we report the effect of a single or successive cycles of anoxia/reoxygenation (A/R) on the mitochondrial respiratory function of equine endothelial cells (cultured from carotids) monitored by high resolution oxymetry, and on their production of reactive oxygen species (ROS). ROS were measured by electron paramagnetic resonance (ESR) using POBN and DMPO spin traps, and by gas chromatography (GC) of ethylene released by ROS-induced alpha-keto-gamma-(methylthio)butyric acid (KMB) oxidation. The oxygen consumption significantly decreased with the number of A/R cycles, and POBN-ESR spectra were specific of adducts formed in the cells from superoxide anion. After a one-hour A/R cycle, high intensity DMPO-ESR spectra were observed and assigned to superoxide anion trapping; the GC results confirmed an important production of ROS compared to normoxic cells. These results show that A/R induces mitochondrial alterations in endothelial cells, and strongly stimulates their oxidative activity as demonstrated by ESR and GC methods. [less ▲]

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See detailModulatory activities of Agelanthus dodoneifolius (Loranthaceae) extracts on stimulated equine neutrophils and myeloperoxidase activity
Boly, Rainatou; Dessy, Stephanie; Kohnen, Stephan et al

in International Journal of Molecular Medicine (2011), 28

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See detailESR technique for non invasive way to quantify cyclodextrins effect on cell membranes
Grammenos, Angeliki ULg; Mouithys-Mickalad, Ange ULg; Guelluy, Pierre-Henri ULg et al

in Biochemical and Biophysical Research Communications (2010)

A new way to study the action of cyclodextrin was developed to quantify the damage caused on cell membrane and lipid bilayer. The Electron Spin Resonance (ESR) spectroscopy was used to study the action of ... [more ▼]

A new way to study the action of cyclodextrin was developed to quantify the damage caused on cell membrane and lipid bilayer. The Electron Spin Resonance (ESR) spectroscopy was used to study the action of Randomly methylated-beta-cyclodextrin (Rameb) on living cells (HCT-116). The relative anisotropy observed in ESR spectrum of nitroxide spin probe (5-DSA and cholestane) is directly related to the rotational mobility of the probe,which can be further correlated with themicroviscosity. The use of ESR probes clearly shows a close correlation between cholesterol contained in cells and cellular membrane microviscosity. This study also demonstrates the Rameb ability to extract cholesterol and phospholipids in time- and dose-dependent ways. In addition, ESR spectra enabled to establish that cholesterol is extracted from lipid rafts to form stable aggregates. The present work supports that ESR is an easy, reproducible and noninvasive technique to study the effect of cyclodextrins on cell membranes. [less ▲]

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See detailSynthesis of poly(vinyl alcohol)/C60 and poly(N-vinylpyrrolidone)/C60 nanohybrids as potential photodynamic cancer therapy agents
Hurtgen, Marie ULg; Debuigne, Antoine ULg; Mouithys-Mickalad, Ange ULg et al

in Chemistry : An Asian Journal (2010), 5(4), 859-868

Well-defined poly(vinyl acetate) (PVAc) and poly(N-vinylpyrrolidone)-co-poly(vinyl acetate) (PNVPco-PVAc) chains end-capped by Co-(acac)2 (acac=acetylacetonate) and prepared by cobalt-mediated radical ... [more ▼]

Well-defined poly(vinyl acetate) (PVAc) and poly(N-vinylpyrrolidone)-co-poly(vinyl acetate) (PNVPco-PVAc) chains end-capped by Co-(acac)2 (acac=acetylacetonate) and prepared by cobalt-mediated radical polymerization (CMRP) are grafted onto a fullerene. Homolytic Co-C bond cleavage of the polymer chain ends at 30°C releases the polymeric radicals that add onto C60, thereby leading to the corresponding PVAc/C60 and PNVP-co-PVAc/C60 nanohybrids. The [polymer–Co(acac)2]/[C60] molar ratio was varied to adjust the structure of the nanohybrids, and more particularly the number of grafted arms. Finally, the potential of the hydrosoluble PVOH/C60 nanohybrids, which result from the methanolysis of the ester groups of PVAc/C60, and of the PNVP-co-PVAc/C60 nanohybrids as photosensitizers for photodynamic therapy (PDT), was approached. First, photobleaching tests demonstrated the ability of these nanohybrids to produce singlet oxygen upon irradiation, which can play a role in cell damage. Second, cell viability assays demonstrated that both types of nanohybrids are deprived of intrinsic cytotoxicity in the dark, whereas they promoted significant cell mortality when subjected to light treatment. The selective response of these materials to irradiation makes them promising compounds for PDT. [less ▲]

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See detailLa microbiopsie musculaire : un nouvel outil pour le suivi sportif et la détection précoce des dysfonctions musculaires
Votion, Dominique ULg; Fraipont, Audrey ULg; Robert, Céline et al

in 36ème Journée de la Recherche Equine (2010)

The objective of this study was to confirm the practical value of high-resolution respirometry (HRR) applied to biopsies to determine, in horses, the level of training, their athletic ability and for the ... [more ▼]

The objective of this study was to confirm the practical value of high-resolution respirometry (HRR) applied to biopsies to determine, in horses, the level of training, their athletic ability and for the early detection of muscular dysfunction. Materials and methods – The muscle mitochondrial respiration was determined by HRR in 20 endurance horses and 10 trotters sampled at the triceps brachii at different stages of their training. Results – Training increases mitochondrial respiration, in addition, the best performers had the highest rate of respiration. A trotter had abnormally low levels of muscle mitochondrial respiration for its level of training. This horse has presented several episodes of rhabdomyolysis during its racing season. Discussion – The biopsy is easily achievable by the attending veterinarian. This study shows that the athletic ability of horses is closely linked to respiratory muscle function, and suggests the value of HRR for performance prediction. In addition, the RHR has the ability to demonstrate mitochondrial dysfunction potentially responsible for exercise-induced rhabdomyolysis. [less ▲]

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See detailEffect of intensive exercise on plasmatic neutrophil elastase level in eventing and endurance horses
Lejeune, Jean-Philippe ULg; Sandersen, Charlotte ULg; Votion, Dominique ULg et al

in Equine Veterinary Journal. Supplement (2010), 48

Reasons for performing the study – Intensive exercise induces a systemic inflammatory response characterized by an increase of blood neutrophil count and myeloperoxidase (MPO) release. Neutrophil elastase ... [more ▼]

Reasons for performing the study – Intensive exercise induces a systemic inflammatory response characterized by an increase of blood neutrophil count and myeloperoxidase (MPO) release. Neutrophil elastase (NE) could also contribute to tissues lesions by their proteinase activities. Objective – To compare plasmatic NE concentrations before and after different forms of intensive exercise. Materials and Methods – EDTA blood samples were taken from 51 eventing horses (EvH) and 32 endurance horses (EndH) were sampled before the race (T0). Blood sampling was performed 2 h (T1) after completing either phase D of a one or two star eventing competition (n=51) or a 120 or 160 km endurance race (n=32). Plasmatic NE and MPO were measured by a specific equine ELISA. Neutrophil counts and creatine kinase (CK) levels were also measured. A Wilcoxon test for paired samples was used to compare mean values of neutrophils, CK, MPO and NE at T0 and T1 in EvH and in EndH. Correlations were calculated between all the 4 parameters in EvH and EndH. Results – At T0, mean NE levels were 14.43 ± 3.63 ng/ml for EvH and 11.7 ± 2.11 ng/ml for EndH. The competition induced a significant increase of NE levels in (58.57 ± 24.06 ng/mL) EvH and (95.74 ± 22.70 ng/mL) EndH (p < 0,05). NE was significantly (p < 0,0001) correlated to MPO in EvH (r = 0.293) and EndH (0.594) and to CK (r = 0.297) in EndH (p<0.0001). Neutrophils, CK and MPO were significantly increased between T0 and T1 in both types of horses. Conclusions – Significant increase of NE was observed after intense exercise with a significant correlation between NE and MPO. The huge variability in MPO and ELT, indicates, that not all horses show the same intensity of systemic inflammatory response. [less ▲]

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See detailAlterations in mitochondrial respiratory function in response to endurance training and endurance racing
Votion, Dominique ULg; Fraipont, Audrey ULg; Goachet, Anne-Gaëlle et al

in Equine Veterinary Journal. Supplement (2010), 42(38), 268-274

Objectives: To determine effects of training and racing on muscle oxidative phosphorylation (OXPHOS) and electron transport system (ETS) capacities in horses with high-resolution respirometry (HRR).

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See detailAMADEOX method : combination of various techniques to distinguish stoichiometric and anticatalytic activities of antioxidant molecules or natural extracts
Franck, Thierry ULg; Mouithys-Mickalad, Ange ULg; Kohnen, Stephan et al

in International Society of Antioxidants in Nutrition & Health, 5th International Conference on Polyphenols Applications, Bridging Bioefficacy to Innovations & Applications, October 29th-30th 2009, Malta (2009, October 29)

We developed an original method called AMADEOX (for « Action Modulatrice de l'Activité Des Enzymes Oxydantes ») able to distinguish stoichiometric, metabolic and anticatalytic activities of antioxidant ... [more ▼]

We developed an original method called AMADEOX (for « Action Modulatrice de l'Activité Des Enzymes Oxydantes ») able to distinguish stoichiometric, metabolic and anticatalytic activities of antioxidant molecules or natural extracts on stimulated neutrophils and purified myeloperoxidase (MPO), a key enzyme released by neutrophil and acting as one of the major ROS generating systems. [less ▲]

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See detailEffect de l'entraînement sur la fonction mitochondriale musculaire du cheval d'endurance
Votion, Dominique ULg; Fraipont, Audrey ULg; Franck, Thierry ULg et al

in 35eme Journee de la Recherche Equine, jeudi 26 fevrier 2009, Paris, France (2009)

Athletic ability of endurance horses is intimately linked to muscle oxidative capacity. Microbiopsies of triceps brachii (TB) and gluteus medius (GM) were collected before and after 10 weeks of training ... [more ▼]

Athletic ability of endurance horses is intimately linked to muscle oxidative capacity. Microbiopsies of triceps brachii (TB) and gluteus medius (GM) were collected before and after 10 weeks of training in 7 endurance horses to assess the feasibility of studying training effect with the use of microbiopsies. Oxygen consumption of permeabilized fibers was evaluated by high resolution respirometry (HRR) with a titration protocol that defines the activity of the mitochondrial complexes. Differences among muscles before and after training as well as training effect were assessed by Wilcoxon matched pairs test (P<0.05). No complications occurred following microbiopsies in any horse. The in situ oxidative capacity of the TB and GM increased with training. No difference was found between the TB and GM when one horse was excluded from the statistical analysis. Indeed, this horse showed signs of exercise intolerance before sampling (after the training period) which were associated to a low rate of respiration in GM but not in TB. Results of this study showed that HRR may be used to follow training effect and suggest that metabolic impairment might be detected with HRR. [less ▲]

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See detailThe unexpected hidden face of the Cephalosporin Antibiotic Ceftazidime: From biological to chemical and physical activities against oxidant species produced by phagocytes
Mouithys-Mickalad, Ange ULg; Deby-Dupont, Ginette; Mathy-Hartert, Marianne ULg et al

Conference (2008, October 03)

Background: Over several decades the use of antibiotics to treat infectious and bacterial diseases has been the main challenge. Ceftazidime (CAZ), belonging to the cephalosporin’s family, is known as ... [more ▼]

Background: Over several decades the use of antibiotics to treat infectious and bacterial diseases has been the main challenge. Ceftazidime (CAZ), belonging to the cephalosporin’s family, is known as empiric treatment for severe sepsis. Beside its antibiotic effect, CAZ has been shown to have other properties, making it unique. This study is aimed to investigate unexpected antioxidant properties of CAZ with special emphasis on the mechanism of action. Methods: Four in vitro and ex-vivo experimental models were designed 1) Assay of proteinases inhibitory activity of α2-macroglobulin (α2M) in the presence of trypsine (1.4µg) with or without 10-3 M CAZ, in 0.1 M Tris-HCl at pH 8.1. 2) Assessment of MPO-induced toxicity on endothelial cells or oxidant activities of stimulated phagocytes (PMNs) using 160 µM ferricytochrome C. 3) Effect of CAZ on two models of anoxia/reoxygenation from adherent and suspension alveolar cells (A549, 106 to 1010 cells/ml) using oxymetry coupled to EPR-spin trapping technique. 4) Cell-free systems to investigate: lipoperoxidation of linoleate induced by γ-irradiation, Fe2+/ascorbate system or ferryl species; Quenching of hydroxyl radical (·OH) and singlet oxygen (1O2)-scavenging activity from Mallet’s (H2O2/NaOCl) and Fenton’ reactions. Results: Ex-vivo assays show efficient protective effect of CAZ on plasmatic antiproteinases against oxidative stress; a dose-dependent inhibitory capacity on endothelial and A549 cells against MPO toxicity or excessive production of ROS during anoxia/reoxygenation. On cell-free systems, CAZ had unique 1O2–scavenging activity; and less effect on ferryl species. CAZ exerts its antioxidant effect by chelating activity. Conclusions: Overall results indicate that: 1) CAZ protects endothelial cells against MPO toxicity but also A549 cells towards the effect of anoxia/reoxygenation; 2) CAZ protects α2M and 3) acts as efficient inhibitor of lipid peroxidation of linoleate and hydroxyl radical and as singlet oxygen-scavengers. Antioxidant properties of CAZ might be relevant in clinical situations where excessive activation of leukocytes is known and in anoxia/reoxygenation model cause an increased production of ROS. [less ▲]

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See detailLes nouveaux outils d’investigation des myopathies « typiques » et atypique.
Votion, Dominique ULg; van Galen, Gaby; Deby-Dupont, Ginette et al

(2008, October)

This paper aims at describing new investigation tools that are currently under development. Oxymetry, electron spin resonance and myeloperoxidase assays may be applied on muscle sample taken by ... [more ▼]

This paper aims at describing new investigation tools that are currently under development. Oxymetry, electron spin resonance and myeloperoxidase assays may be applied on muscle sample taken by microbiopsy as well as on culture of myocytes. In a next future, these tools should improve our knowledge of the pathophysiological mechanisms involved in clinical and subclinical equine myopathies. [less ▲]

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