References of "Deby-Dupont, G."
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See detailCytotoxicity of Stimulated Equine Neutrophils on Equine Endothelial Cells in Culture
Benbarek, H.; Grulke, Sigrid ULg; Deby-Dupont, G. et al

in Equine Veterinary Journal (2000), 32(4), 327-33

We studied the interactions of isolated equine neutrophils with endothelial cells in culture, mimicking a situation of acute inflammation. Our main purpose was to demonstrate that the supernatant of ... [more ▼]

We studied the interactions of isolated equine neutrophils with endothelial cells in culture, mimicking a situation of acute inflammation. Our main purpose was to demonstrate that the supernatant of activated neutrophils was sufficient to damage endothelial cells. Equine endothelial cells (from carotid arteries) were covered either with increased numbers of equine neutrophils stimulated by phorbol myristate acetate, or with the supernatant collected after an in vitro stimulation of the neutrophils. Cytotoxicity was estimated by the release of preincorporated 51Cr, and by light microscopy observations. To assert the specific role of reactive oxygen species, endothelial cells were treated by the hypoxanthine/xanthine oxidase (X/XOx) system (production of superoxide anion and hydrogen peroxide), and by hypochlorite (product of the activity of myeloperoxidase). A strong cytotoxicity was found with stimulated neutrophils; microscopic observations indicated a loss of 50% of the endothelial cells and morphological alterations in the remaining cells. The supernatant of stimulated neutrophils was cytotoxic, in correlation with the number of neutrophils used to obtain the supernatant, and with the supernatant concentration of myeloperoxidase. The cytotoxicity of the X/XOx system was weak, but was increased by myeloperoxidase. Hypochlorite was highly toxic. We concluded that the supernatant of stimulated neutrophils was sufficient to obtain cytotoxic effects on the endothelium, in the absence of a direct contact between endothelium and neutrophils, and that this cytotoxicity was mainly linked to the activity of myeloperoxidase. From these in vitro results, it can be extrapolated that in pathologies characterised by an important activation of neutrophils, damage can spread to cells and tissues away from the inflammation focus. [less ▲]

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See detailHigh Concentrations of Histamine Stimulate Equine Polymorphonuclear Neutrophils to Produce Reactive Oxygen Species
Benbarek, H.; Mouithys-Mickalad, Ange ULg; Deby-Dupont, G. et al

in Inflammation Research (1999), 48(11), 594-601

OBJECTIVE AND DESIGN: Because high concentrations of histamine are locally released in inflammation, we investigated the effects of supraphysiological doses of histamine on the production of reactive ... [more ▼]

OBJECTIVE AND DESIGN: Because high concentrations of histamine are locally released in inflammation, we investigated the effects of supraphysiological doses of histamine on the production of reactive oxygen species (ROS) by neutrophils. MATERIALS AND METHODS: Isolated equine neutrophils were activated by 10(-4) to 5 x 10(-3) M histamine. The production of ROS and free radicals was estimated by luminol-enhanced chemiluminescence (CL) and electron spin resonance (ESR) with spin trapping technique. In this model of histamine-stimulated neutrophils, we tested the antagonists of H1 and H2 histamine receptors, the role of Ca2+ and Mg2+, the role of staurosporine and pertussis toxin (inhibitors of protein kinase C and proteins G) and the effects of superoxide dismutase, catalase, hydroxyl radical scavengers (phenylalanine and mannitol) and N(G)-monomethyl-L-arginine (L-NMMA), inhibitor of NO-synthase. RESULTS: Histamine (from 10(-5) to 10(-3) M) stimulated neutrophils to produce CL and ESR signals characterized by spin adducts of superoxide anion and/or hydroxyl radicals. The CL response was inhibited by 10(-4) and 10(-3) M H1 receptor antagonists (promethazine, pyrilamine, and diphenhydramine), by Ca2+ and Mg2+ depletion and by 10 nmoles staurosporine. CL was partially inhibited by pertussis toxin (4 microg/ mL). The ESR signals were practically suppressed by pyrilamine (an H1 receptor antagonist) and superoxide dismutase, and partially inhibited by catalase, hydroxyl radical scavengers and L-NMMA (respectively 59, +/- 30% and 68% inhibition). CONCLUSIONS: High concentrations of histamine stimulated the neutrophils to product ROS and free radicals via H1 receptors and the NADPH-oxidase pathway. [less ▲]

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See detailEffects of Acepromazine on Equine Polymorphonuclear Neutrophil Activation: A Chemiluminescence Study
Serteyn, Didier ULg; Benbarek, H.; Deby-dupont, G. et al

in Veterinary Journal (1999), 157(3), 332-5

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See detailPlasma Myeloperoxidase Level and Polymorphonuclear Leukocyte Activation in Horses Suffering from Large Intestinal Obstruction Requiring Surgery: Preliminary Results
Grulke, Sigrid ULg; Benbarek, Hama; Caudron, I. et al

in Canadian Journal of Veterinary Research = Revue Canadienne de Recherche Vétérinaire (1999), 63(2), 142-7

Myeloperoxidase (MPO) is a specific enzyme of neutrophil azurophilic granules with a strong oxidative activity. Thanks to a radioimmunoassay of equine myeloperoxidase, the authors have observed a ... [more ▼]

Myeloperoxidase (MPO) is a specific enzyme of neutrophil azurophilic granules with a strong oxidative activity. Thanks to a radioimmunoassay of equine myeloperoxidase, the authors have observed a significantly higher plasma level of MPO in horses operated for strangulation obstruction of the large intestine (n = 6) than in horses suffering from a non-strangulating displacement of the large intestine (n = 9). For the 2 groups, 3 phases were distinguished: reception (P1), intensive care (P2) and terminal phase (P3). The mean peak values of MPO for these phases were 121.6 ng/mL (P1), 168.6 ng/mL (P2), and 107.0 ng/mL (P3) for the non-strangulating group, and 242.6 ng/mL (P1); 426.0 ng/mL (P2), and 379.5 ng/mL (P3) for the strangulation group. The variations of the mean peak values of plasma MPO were significantly different between the 2 groups and between the different phases. A significant increase of the least square means of MPO was observed between P1 and P2. A significant decrease of the least square means of the number of circulating leukocytes was observed between P1 and P3. Polymorphonuclear neutrophil activation could play a major role in the pathogenesis of acute abdominal disease and endotoxic shock. [less ▲]

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See detailInteractions between Lipopolysaccharides and Blood Factors on the Stimulation of Equine Polymorphonuclear Neutrophils
Benbarek, H.; Deby-Dupont, G.; Caudron, I. et al

in Veterinary Immunology & Immunopathology (1998), 64(4), 313-22

In horses, the mechanisms of lipopolysaccharide (LPS) stimulation of isolated neutrophils to produce reactive oxygen species remain unknown. We re-investigated this problem by monitoring the luminol ... [more ▼]

In horses, the mechanisms of lipopolysaccharide (LPS) stimulation of isolated neutrophils to produce reactive oxygen species remain unknown. We re-investigated this problem by monitoring the luminol-enhanced chemiluminescence (CL) produced by LPS-stimulated equine neutrophils. The neutrophils were isolated from horse blood by discontinuous density gradient centrifugation (> or = 99% neutrophils; viability > or = 98%). Increasing concentrations of Escherichia coli (E. coli) LPS (from 0.01-10 microg ml(-1)) were used to activate the neutrophils. When LPS was used directly, without another stimulator, the respiratory burst of neutrophils was not activated (N=12 horses; n=5 assays per horse). On the contrary, when LPS was added to whole blood, the neutrophils isolated from this blood were stimulated in a LPS dose-dependent manner, but polymyxin B added to whole blood suppressed this stimulation (N=2; n=6). LPS dissolved in autologous equine plasma stimulated the isolated neutrophils in a dose-dependent manner from 0.1-10 microg ml(-1) (N=5; n=12). Heat inactivation of the plasma abolished this CL increase (N=2; n=5). LPS added to equine albumin did not stimulate the isolated neutrophils (N=2; n=5). On the contrary, the addition of gamma-globulins (1 mg ml(-1)) to LPS (10 microg ml(-1)) led to the stimulation of neutrophils (N=2; n=5). We concluded that LPS did not directly stimulate the isolated equine neutrophils, but that plasmatic factors are needed for the stimulation of these cells by LPS. [less ▲]

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See detailOxidant-Scavenging Activities of Beta-Lactam Agents
Carreer, R.; Deby-Dupont, G.; Deby, C. et al

in European Journal of Clinical Microbiology & Infectious Diseases : Official Publication of the European Society of Clinical Microbiology (1998), 17(1), 43-6

The relative antioxidant effect of ampicillin, ceftazidime, ceftriaxone, and cefuroxime on oxygen-reactive species was examined in vitro using stimulated human polymorphonuclear neutrophils. There was no ... [more ▼]

The relative antioxidant effect of ampicillin, ceftazidime, ceftriaxone, and cefuroxime on oxygen-reactive species was examined in vitro using stimulated human polymorphonuclear neutrophils. There was no evidence that any of the beta-lactam agents tested had an effect on superoxide or H2O2 generation. In contrast, all of the beta-lactam agents prevented hypochlorous acid (HOCI) chlorination of 1,1-dimethyl-4-chloro-3,5-cyclo-hexanedione in a cell-free system at concentrations of < 10 microg/ml. Furthermore, all antibiotics provided dose-dependent protection against HOCI cytotoxicity to 16HBE140 bronchial epithelial cells. Taken together, these data indicate a possible therapeutic role for beta-lactam agents in protecting host tissues from HOCI-induced oxidative damage. [less ▲]

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See detailPropofol reacts with peroxynitrite to form phenoxyl radicals. Demonstration by ESR
Mouithys-Mickalad, Ange ULg; Hans, P.; Deby-Dupont, G. et al

Conference (1998)

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See detailFailure of Lipopolysaccharides to Directly Trigger the Chemiluminescence Response of Isolated Equine Polymorphonuclear Leukocytes
Benbarek, H.; Deby-Dupont, G.; Caudron, I. et al

in Veterinary Research Communications (1997), 21(7), 477-82

Divergent results have been reported on the effects of lipopolysaccharides (LPS) on the activation of equine polymorphonuclear leukocytes (PMN). We therefore attempted to determine whether LPS alone can ... [more ▼]

Divergent results have been reported on the effects of lipopolysaccharides (LPS) on the activation of equine polymorphonuclear leukocytes (PMN). We therefore attempted to determine whether LPS alone can stimulate equine PMN or whether plasma factors are necessary. PMN were isolated from citrated blood on a discontinuous density gradient of Percoll. The luminol (10(-3) mol/L)-enhanced chemiluminescence (CL) of 1.25 x 10(6) cells was measured after addition of Escherichia coli LPS (0.001-10 micrograms/ml) alone or after incubation in autologous plasma (1 h, 37 degrees C). After direct stimulation with LPS, there were random variations of CL in 16 horses that were not reproducible from one sample to the next for the same horse. LPS which had been incubated in plasma gave a dose-dependent stimulation of the CL of the PMN, which did not occur if the plasma had been heat inactivated (1 h, 56 degrees C). These results indicated a role for plasma factors, which were unlikely to be cytokines, as there were no monocytes or lymphocytes in the plasma incubated with LPS, but might have been complement fragments or LPS ligands, such as LPS binding protein. Studies using specific antibodies against these factors are needed to clarify this question. [less ▲]

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See detailEffects of training on myocellular enzyme leakage and delayed onset muscle soreness following maximal isokinetic eccentric exercise
Croisier, Jean-Louis ULg; Camus, Gérard; Duchateau, J. et al

in Mediators of Inflammation (1997), 6

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See detailEffect of Propofol on in Vitro Lipid Peroxidation Induced by Different Free Radical Generating Systems: A Comparison with Vitamin E
Hans, Pol ULg; Deby, Christiane ULg; Deby-Dupont, G. et al

in Journal of Neurosurgical Anesthesiology (1996), 8(2), 154-8

Propofol has been reported to have antioxidant properties and to inhibit lipid peroxidation. In this study, we examined the ability of propofol to inhibit lipid peroxidation induced by three free radical ... [more ▼]

Propofol has been reported to have antioxidant properties and to inhibit lipid peroxidation. In this study, we examined the ability of propofol to inhibit lipid peroxidation induced by three free radical systems (hydroxyl, ferryl, and oxo-ferryl radicals), and we compared the effect of propofol with that of vitamin E, an endogenous antioxidant. Lipid peroxidation was induced by exposing a linoleic acid emulsion to either water gamma radiation, a ferrous iron-ascorbate solution, or human hemoglobin, generating the hydroxyl, ferryl, and oxo-ferryl radicals, respectively. Each experiment was performed in triplicate with and without propofol or vitamin E at concentrations between 10(-5) and 10(-4) M. Lipid peroxidation was quantified by gas chromatography measurement of the pentane released (nmoles) from lipid decomposition. In each condition, a significant dose-response relationship was found between the release of pentane and the concentration of either propofol or vitamin E. The antioxidant activities of both agents were similar but significantly higher against the hydroxyl than the ferryl and oxo-ferryl radicals. The study suggests that propofol could be beneficial as an anesthetic or sedative drug in patients presenting pathologies associated with free radical reactions. [less ▲]

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See detailPiroxicam fails to reduce myocellular enzyme leakage and delayed onset muscle soreness induced by isokinetic eccentric exercise
Croisier, Jean-Louis ULg; Camus, Gérard; Deby-Dupont, G. et al

in Pflügers Archiv : European Journal of Physiology (1996), 431

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See detailPrevention of postmenopausal bone loss by administration of boron
Biquet, I; COLLETTE, Julien ULg; Dauphin, JF et al

in Osteoporosis International (1996), 6(S1), 249

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See detailMyocellular Enzyme Leakage, Polymorphonuclear Neutrophil Activation and Delayed Onset Muscle Soreness Induced by Isokinetic Eccentric Exercise
Croisier, Jean-Louis ULg; Camus, Gérard; Deby-Dupont, G. et al

in Archives of Physiology & Biochemistry (1996), 104(3), 322-9

To address the question of whether delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of the arachidonic acid derived product ... [more ▼]

To address the question of whether delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of the arachidonic acid derived product prostaglandin E2 (PGE2). 10 healthy male subjects were submitted to eccentric and concentric isokinetic exercises on a Kin Trex device at 60 degrees/s angular velocity. Exercise consisted of 8 stages of 5 maximal contractions of the knee extensor and flexor muscle groups of both legs separated by 1 min rest phases. There was an interval of at least 30 days between eccentric and concentric testing, and the order of the two exercise sessions was randomly assigned. The subjective presence and intensity of DOMS was evaluated using a visual analogue scale, immediately, following 24 h and 48 h after each test. Five blood samples were drawn from an antecubital vein: at rest before exercise, immediately after, after 30 min recovery, 24 h and 48 h after the tests. The magnitude of the acute inflammatory response to exercise was assessed by measuring plasma levels of polymorphonuclear elastase ([EL]), myeloperoxidase ([MPO]) and PGE2 ([PGE2]). Using two way analysis of variance, it appeared that only eccentric exercise significantly increased [EL] and DOMS, especially of the hamstring muscles. Furthermore, a significant decrease in eccentric peak torque of this muscle group only was observed on day 2 after eccentric work (- 21%; P < 0.002). Serum activity of creatine kinase and serum concentration of myoglobin increased significantly 24 and 48 h after both exercise tests. However, these variables reached significantly higher values following eccentric contractions 48 h after exercise. Mean [PGE2] in the two exercise modes remained unchanged over time and were practically equal at each time point. On the basis of these findings, we conclude that the magnitude of polymorphonuclear (PMN) activation, muscle damage, and DOMS are greater after eccentric than after concentric muscle contractions. However, the hypothesized interplay between muscle damage, increased PGE2 production, DOMS sensations, and reduced isokinetic muscle performance was not substantiated by the present results. [less ▲]

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See detailApproche directe pour la mise en évidence des phénomènes radicalaires lors de myopathie postanesthésique équine: étude préliminaire
Serteyn, Didier ULg; Pincemail, Joël ULg; Mottart, E. et al

in Canadian Journal of Veterinary Research = Revue Canadienne de Recherche Vétérinaire (1994), 58(4), 309-12

This preliminary study demonstrated the existence of a free radical generation during an experimental postischemic muscular reperfusion in a halothane anesthetized horse. The authors used alpha-phenyl-N ... [more ▼]

This preliminary study demonstrated the existence of a free radical generation during an experimental postischemic muscular reperfusion in a halothane anesthetized horse. The authors used alpha-phenyl-N-tert-butylnitrone as a spin trap agent and the electronic paramagnetic resonance method to observe in vivo a free radical generation. [less ▲]

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See detailEvidence for Free Radical Formation During Human Kidney Transplantation
Pincemail, Joël ULg; Defraigne, Jean-Olivier ULg; Franssen, Christine ULg et al

in Free Radical Biology & Medicine (1993), 15(3), 343-8

Fourteen patients undergoing kidney transplantation were studied for evidence of the production of free radicals as assessed by the measurement of vitamin E (an index of lipid peroxidation) and of ... [more ▼]

Fourteen patients undergoing kidney transplantation were studied for evidence of the production of free radicals as assessed by the measurement of vitamin E (an index of lipid peroxidation) and of myeloperoxidase (a marker of neutrophil activation) in the systemic blood. Early (2 min) and late revascularization (30 min) of the kidney were respectively associated with a significant decrease of 35.5 and 40% of the initial level of plasma vitamin E. This consumption paralleled to the decrease of the vitamin E/total lipids ratio, a better indicator of vitamin E status. Heparin administration preceding renal artery clamping resulted in a twofold significant increase of baseline plasma myeloperoxidase (MPO) level (523 +/- 214 ng/ml). At kidney reperfusion, MPO concentration rose again and reached a maximum value of 1,653 +/- 882 ng/ml, indicating the presence of considerable neutrophil activation. A return to the baseline value was observed after 30 min of reperfusion. A short discussion about the possible origin of this MPO increase is given. Taken together, these data strongly suggest that free radical production, leading to lipid peroxidation phenomena, can occur within the early phase of kidney revascularization. Preliminary data using electron spin resonance with the spin-trapping technique strengthen this hypothesis. [less ▲]

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See detailActive oxygen species, articular inflammation and cartilage damage
Henrotin, Yves ULg; Deby-Dupont, G; Deby, C et al

in Emerit, I; Chance, B (Eds.) Free Radicals and Aging (1993)

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See detailProduction of active oxygen species by isolated human chondrocytes.
Henrotin, Yves ULg; Deby-Dupont, G.; DEBY, C. et al

in British Journal of Rheumatology (1993), 32(7), 562-7

The ability of isolated human chondrocytes to produce active oxygen species has been investigated. The two methods for determining H2O2 and hydroxyl radicals (.OH) production were, by a fluorimetric ... [more ▼]

The ability of isolated human chondrocytes to produce active oxygen species has been investigated. The two methods for determining H2O2 and hydroxyl radicals (.OH) production were, by a fluorimetric method (production of dichlorofluorescein from a precursor in the presence of horseradish peroxidase and H2O2) and by a chromatographic method (measurement of ethylene production from gamma-methiol-keto-butyric acid after .OH attack). Chondrocytes were tested, both with and without activation by phorbol myristate acetate (PMA: 10(-6) M), in the presence of Ca2+ (1 x 10(-4) M) and Mg2+ (2 x 10(-4) M) or after variable periods of anoxia under nitrogen (4 to 12 h) followed by reoxygenation (with 95% O2, 5% CO2). Under these experimental conditions, the PMA-excited chondrocytes produced from 80 to 180 nmol of hydrogen peroxide per 1 x 10(6) cells and chondrocytes subjected to anoxia-reoxygenation produced up to 1700 nmol H2O2 per 1 x 10(6) cells. The hydroxyl radical production by PMA or anoxia-reoxygenation excited cells reached 600% of the production of non-excited cells and 1300% when they were subjected to successive stimulations by PMA and anoxia-reoxygenation. The possible pathological significance of these observations is discussed. The results indicate that stimulated human chondrocytes are capable of producing active oxygen species which could play a major role in joint inflammation and cartilage damage. [less ▲]

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See detailMeasurements of mediator cascades during adult respiratory distress syndrome
Lamy, Maurice ULg; Deby-Dupont, G.; Deby, C. et al

in Adult Respiratory Distress Syndrome (1992)

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