References of "Mouithys-Mickalad, Ange"
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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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See detailDiselenide Derivative, Potential Successor of Ebselen with High Antioxidant Activity: Assessment on in vitro Models
Mareque-Faez, Juan; Deby, Carol; Lamy, Maurice ULg et al

in Resource-Full Chemistry (2008, May 24)

Oxidative stress plays a key role in several pathophysiological events, including the attack of DNA, cell membrane damage and signaling pathways disruption. The harmful effect of oxidant stress has been ... [more ▼]

Oxidative stress plays a key role in several pathophysiological events, including the attack of DNA, cell membrane damage and signaling pathways disruption. The harmful effect of oxidant stress has been attributed to a high production of reactive oxygen species (ROS) followed by a depletion of antioxidant enzymes, glutathione peroxidase (GPx), a mammalian selenoenzyme which functions as a catalytic antioxidant, has been described to protect various organisms against oxidative stress. In the past two decades, the design of small weight molecules such as ebselen (PZ 51, 2-phenyl-1,2-benzoisoselenazol-3(2H)-one), has renewed the interest of synthetic analogues able to mimic the GPx activity. From four in vitro in vitro models, we previously showed that ebselen and some of its analogues (compounds 1, 2, 3 and 4) not only behaved at various degrees as GPx-like mimics but also as antioxidants especially for diselenide derivative (3). The present study deals with the antioxidant effect of diselenide derivative (3) versus ebselen on cellular model and the enzyme myeloperoxidase (MPO) activity using the in vitro systems. Derivative (3) has been chosen because of its interesting antioxidant profile in cell-free systems. [less ▲]

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See detailResveratrol inhibits the activity of equine neutrophil Myeloperoxidase by a direct interaction with the enzyme
Kohnen, Stephan ULg; Franck, Thierry ULg; Van Antwerpen, Pierre et al

in Journal of Agricultural and Food Chemistry (2007), 55(20), 8080-8087

Resveratrol is a polyphenolic antioxidant present in beverage and food known for its multiple protective effects. We report the inhibitory effects of resveratrol on equine myeloperoxidase (MPO), a hemic ... [more ▼]

Resveratrol is a polyphenolic antioxidant present in beverage and food known for its multiple protective effects. We report the inhibitory effects of resveratrol on equine myeloperoxidase (MPO), a hemic peroxidase present in the granules of the neutrophils involved in the inflammatory response. Resveratrol inhibited the production of reactive oxygen species (ROS) by stimulated equine neutrophils by acting as a direct scavenger of the ROS released by the cells but did not modify the degranulation of the stimulated neutrophils as the amounts of released MPO were unchanged. Resveratrol strongly inhibited the chlorination, oxidation, and nitration activities of MPO in a dose-dependent manner. By an original technique of specific immunological extraction followed by enzymatic detection (SIEFED), we demonstrated that resveratrol inhibited the peroxidasic activity of the MPO measured by a direct interaction such as the fixation of resveratrol on the enzyme. The observation of a decrease of the accumulation of compound II suggested that resveratrol acts as an electron donor for MPO reduction. [less ▲]

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See detailC-60-containing nanostructured polymeric materials with potential biomedical applications
Stoilova, Olya; Jérôme, Christine ULg; Detrembleur, Christophe ULg et al

in Polymer (2007), 48(7), 1835-1843

Star-shaped polymers with a fullerene (C-60) Core and an unexpanded structure were successfully prepared by reaction Of C60 with amino end-capped polyesters HxC60(NHPCLn)(x) and polyethers HxC60(NHPEG(n ... [more ▼]

Star-shaped polymers with a fullerene (C-60) Core and an unexpanded structure were successfully prepared by reaction Of C60 with amino end-capped polyesters HxC60(NHPCLn)(x) and polyethers HxC60(NHPEG(n))(x), respectively. Upon irradiation of these C-60-derivatives, a large amount of singlet oxygen was released. Compared to previously synthesized star-shaped azafulleroids with an expanded structure, the photosensitivity of HxC60(NHPCLn)(x) is higher as assessed by a higher production of singlet oxygen. The cytotoxicity of the photoactive water-soluble HxC60(NHPEG(n))(x) derivatives was tested against THP-1 cells and expressed in terms of cell viability. Moreover, they were processed as micro-/nanosized fibers by electrospinning, which however required the addition of poly(F-caprolactone) (PCL). The diameter distribution of the fibers was trimodal, where the fraction with the 270 nm average diameter was the major population. Because of their photoactivity, the herein reported star-shaped C-60-derivatives are promising candidates for photodynamic cancer therapy and treatment of multidrug resistant pathogens. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailOxygen consumption of equine articular chondrocytes: Influence of applied oxygen tension and glucose concentration during culture.
Schneider, Nicole ULg; Mouithys-Mickalad, Ange ULg; Lejeune, Jean-Philippe ULg et al

in Cell Biology International (2007), 31

We investigated the oxygen (O2) uptake of equine articular chondrocytes to assess their reactions to anoxia/re-oxygenation. They were cultured under 5% or 21% gas phase O2 and at glucose concentrations of ... [more ▼]

We investigated the oxygen (O2) uptake of equine articular chondrocytes to assess their reactions to anoxia/re-oxygenation. They were cultured under 5% or 21% gas phase O2 and at glucose concentrations of 0, 1.0 or 4.5 g/L in the culture medium (n = 3). Afterwards, the O2 consumption rate of the chondrocytes was monitored (oxymetry) before and after an anoxia period of 25 min. The glucose consumption and lactate release were measured at the end of the re-oxygenation period. The chondrocytes showed a minimal O2 consumption rate, which was hardly changed by anoxia. Independently from the O2 tension, glucose uptake by the cells was about 30% of the available culture medium glucose, thus higher for cells at 4.5 g/L glucose (n = 3). Lactate release was also independent from O2 tension, but lower for cells at 4.5 g/L glucose (n = 3). Our observations indicated that O2 consumption by equine chondrocytes was very low despite a functional mitochondrial respiratory chain, and nearly insensitive to anoxia/re-oxygenation. But the chondrocytes metabolism was modified by an excess of O2 and glucose. [less ▲]

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See detailSYNOVIOCYTES, NOT CHONDROCYTES, RELEASE FREE RADICALS AFTER CYCLES OF ANOXIA/RE-OXYGENATION
Schneider, Nicole ULg; Mouithys-Mickalad, Ange ULg; Lejeune, Jean-Philippe ULg et al

Poster (2007)

Introduction : An oxidant activity has been implicated in the onset of equine osteoarthritis. Most of the studies have been done on articular chondrocytes, but little is known about the role of ... [more ▼]

Introduction : An oxidant activity has been implicated in the onset of equine osteoarthritis. Most of the studies have been done on articular chondrocytes, but little is known about the role of synoviocytes. Objective : Our aim was to investigate if equine articular chondrocytes, primary synoviocytes or synoviocytes of a continuous cell line are able to produce free radicals after exposure to anoxia and re-oxygenation. Methods : By oxymetry and electron paramagnetic resonance (EPR), we investigated the effects of repeated anoxia/re-oxygenation (A/R) periods on the respiration and production of free radicals by synoviocytes (rabbit HIG-82 cell line and primary equine synoviocytes) and equine articular chondrocytes. Three periods of 20 min anoxia followed by re-oxygenation were applied to 10exp7 cells; O2 consumption was measured before anoxia and after each re-oxygenation. After the last A/R, cellular free radical formation was investigated by EPR spectroscopy with spin trapping technique (n = 3 for each cell line). Results : Both types of synoviocytes showed a high O2 consumption, which was slower after anoxia. By EPR with the spin trap POBN, we proved a free radical formation. Results were similar for equine and rabbit synoviocytes. For chondrocytes, we observed a low O2 consumption, unchanged by anoxia, and no free radical production. Conclusion : These observations suggest an oxidant activity of synoviocytes, potentially important for the onset of osteoarthritis. [less ▲]

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See detailAre COX-2 Inhibitors Active on Intracellular Oxidative Processes? A Study on In Vitro and Cellular Models
Mouithys-Mickalad, Ange ULg; Deby-Dupont, Ginette; Deby, Carol et al

Book published by Nova Science Publishers, Inc. (2006)

In the last years, there has been an increasing interest of using cyclooxygenase-2 (COX-2) inhibitors to treat the inflammatory pain and chronic inflammatory diseases such as osteoarthritis and rheumatoid ... [more ▼]

In the last years, there has been an increasing interest of using cyclooxygenase-2 (COX-2) inhibitors to treat the inflammatory pain and chronic inflammatory diseases such as osteoarthritis and rheumatoid arthritis. The beneficial effects were to avoid the secondary adverse effects such as bleeding and gastric irritation, generally observed with aspirin and conventional NSAIDs. COX-1 is constitutively expressed in most tissues and involved in the regulation of normal homeostatic functions, while COX-2 is not detected in most tissues but induced by inflammatory stimuli. These outcomes motivated the commercial development of selective COX-2 inhibitors. Recent data suggested that the COX-2 enzyme can be expressed within atherosclerotic lesions and could play a crucial role in various types of cancers, by the way of its activity on the ROS production, gene transcription and prostaglandin (PGE2) production. Consequently, the COX-2 enzyme has become a real target for the study of various classes of compounds and specially the possible additional properties of COX-2 inhibitors. We and other groups have already investigated the pro or antioxidant profile of conventional NSAIDs and some COX-2 inhibitors. With the recent withdrawal of two compounds of the coxib’s family (rofecoxib and celecoxib), for adverse cardiovascular events, concerns regarding the safety of all COX-2 inhibitors have been raised. To answer to these concerns, different approaches were developed by studying on in vitro models, the potential inhibiting-or-stimulating activities on oxidative phenomena of new drugs with already recognized therapeutic effects. Preliminary data obtained with COX-2 inhibitors showed a moderate inhibiting effect on the intracellular oxidant processes and others a stimulating activity. New hypotheses for the treatment of inflammation are now suggested for compounds like nimesulide and its analogous, which are selective towards COX-2 with little activity on COX-1. Here, we reported the in vitro effects of some Cox-2 inhibitors, in comparison with traditional drugs (ibuprofen, diclofenac and aceclofenac) by using two cellular models: a human lung type II alveolar cell line (A549) and a human promonocyte cell line (THP-1). The direct interactions between the drugs and ROS were also investigated in cell-free systems. [less ▲]

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