References of "Lekeux, Pierre"
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See detailEffects of high and low inspired fractions of oxygen on horse erythrocyte membrane properties, blood viscosity and muscle oxygenation during anaesthesia
Portier, Karine; Crouzier, David; Guichardant, Michel et al

in Veterinary Anaesthesia & Analgesia (2009), 36(4), 287-298

To evaluate whether a period of hyperoxia or after a period of hypoxia produced changes attributable to reactive oxygen species in anaesthetized horses. Prospective randomized experimental study. Six ... [more ▼]

To evaluate whether a period of hyperoxia or after a period of hypoxia produced changes attributable to reactive oxygen species in anaesthetized horses. Prospective randomized experimental study. Six healthy (ASA I) geldings, aged 4.5-9.5 years and weighing 510-640 kg(-1). After 30 minutes breathing air as carrier gas for isoflurane, horses were assigned randomly to breathe air as carrier gas (CG0.21) or oxygen as carrier gas (CG1.00) for a further 90 minutes. After an interval of 1 month each horse was re-anaesthetized with the other carrier gas for the 90 minute test period. Ventilation was controlled throughout anaesthesia. Arterial blood was sampled to measure gas tensions, lactate, cholesterol, vitamin E, 4-hydroxy-alkenals, 8-epi-PGF(2 alpha), half haemolysis time, half erythrolysis time, and erythrocyte membrane fluidity. Muscle blood flow and oxygenation were evaluated by near infrared spectroscopy and coloured Doppler. After the first 30 minutes horses were hypoxemic. Subsequently the CG1.00 group became hyperoxaemic (PaO2 similar to 240 mmHg) whereas the CG0.21 group remained hypoxaemic (PaO2 similar to 60 mmHg) and had increased lactate concentration. No significant changes in vitamin E, 4-hydroxy-alkenals, or 8-epi-PGF(2 alpha) concentrations were detected. During the 90 minute test period the CG0.21 group had increased resistance to free-radical-mediated lysis in erythrocytes, whereas the CG1.00 group had slightly decreased resistance of whole blood to haemolysis. CG0.21 induced a progressive muscle deoxygenation whereas CG1.00 induced an increase in muscle oxygen saturation followed by progressive deoxygenation towards baseline. During isoflurane anaesthesia in horses, the hyperoxia induced by changing from air to oxygen induced minimal damage from reactive oxygen species. Using air as the carrier gas decreased skeletal muscle oxygenation compared with using oxygen [less ▲]

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See detailAerosol administration of cefquinome in healthy horses – effect on pulmonary function and lung inflammation
Art, Tatiana ULg; Ramery, Eve ULg; Fraipont, Audrey ULg et al

in Tessier, Caroline; Gerber, Vincent (Eds.) Abstract book: 4th World Equine Airways Symposium (WEAS) (2009)

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See detailPTX3: a new marker for local inflammation ?
Ramery, Eve ULg; Bureau, Fabrice ULg; Art, Tatiana ULg et al

in Proceedings of the 11th ECVCP congress, Thessaloniki, Grece (2009)

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See detailLes maillons de la chaîne de l’oxygène, facteurs potentiels limitant la santé des animaux domestiques
Lekeux, Pierre ULg

in Proceedings: Réunion de l’académie vétérinaire de France (2009)

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See detailRespiratory problems in a high productive dairy herd
Lekeux, Pierre ULg

in In Proceedings: Dutch Bovine Conference (2009)

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See detailBRD complex and recent advances in diagnosis and therapies
Lekeux, Pierre ULg

in Dutch Bovine Conference (2009)

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See detailLa mécanique ventilatoire en tant que facteur limitant de la santé des animaux domestiques
Lekeux, Pierre ULg

in Bulletin de l'Académie Vétérinaire de France (2009), 162(2), 127-131

After a description of the various stages in the consumption of oxygen and a definition of limiting factor, this paper describes why the respiratory system is not always able to perform some of its ... [more ▼]

After a description of the various stages in the consumption of oxygen and a definition of limiting factor, this paper describes why the respiratory system is not always able to perform some of its functions in domestic animals specifically selected for their improved zootechnic or athletic performances [less ▲]

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See detailDust exposure exacerbates the expression of ptx3, a recently discovered acute phase protein, in horses’ airways
Ramery, Eve ULg; Bureau, Fabrice ULg; Lekeux, Pierre ULg

Conference (2009)

Heaves is a common cause of recurrent airway obstruction (R.A.O) that occurs in mature horses stabled in a dusty environment. The long pentraxin PTX3 play an important role in the host defence and over ... [more ▼]

Heaves is a common cause of recurrent airway obstruction (R.A.O) that occurs in mature horses stabled in a dusty environment. The long pentraxin PTX3 play an important role in the host defence and over-expression of PTX3 may contribute to airways injury. Therefore, we hypothesised that PTX3 may have relevance in the understanding of the pathogenesis of recurrent airway obstruction (R.A.O). In the present study, we first investigated the equine PTX3 (ePTX3) structure by cloning, sequencing and western-blotting. A 120pb deletion was found in the second exon of ePTX3 in comparison to human PTX3. Moreover, an alternative splicing occurs with complete deletion of the second exon, resulting in two forms of the protein, “spliced” (32 kD) and “full length” (42 kD). The pentraxin domain is very well conserved in the two forms with 94% of amino-acids conserved between equines and humans. These findings could have implications for the comprehension of the function of each domain of the protein. Then, we studied the effects of dust exposure and subsequent R.A.O crisis on ePTX3 expression in the broncho-alveolar lavage fluid (BALF) and the bronchial epithelial cells. PTX3 could be detected in BALF macrophages, neutrophils, eosinophils and bronchial epithelial cells. It was over-expressed in the BALF supernatant from RAO-affected horses in crisis. Dust exposure induced PTX3 in BALF macrophages either in healthy horses or in R.A.O-affected horses. Conversely, PTX3 was strongly over-expressed in the bronchial epithelial cells from R.A.O-affected horses in crisis. Considering epithelial cells as one of the major cell types in the airways, PTX3 produced at this level may play an important role in inflammatory process. Moreover, it suggests that dust-induced expression of PTX3 is differentially regulated in macrophages and bronchial-epithelial cells. A JNK-dependant, NFκB-independent regulatory pathway has been described in lung epithelial cells. A comparable mechanism could be involved in bronchial epithelial cells. If this is confirmed, PTX3 expression in respiratory epithelial cells could be therapeutically targeted. [less ▲]

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See detailIdentification of equid herpesvirus-5 in respiratory liquids: A retrospective study of 785 samples taken in 2006-2007
Fortier, Guillaume; Pronost, Stéphane; Miszczak, Fabien et al

in Veterinary Journal (2009), 182

During a case control study undertaken in 2006-2007, a screening and consensus polymerase chain reaction (PCR) was performed to evaluate the potential role of equid herpesviruses (EHV) in several ... [more ▼]

During a case control study undertaken in 2006-2007, a screening and consensus polymerase chain reaction (PCR) was performed to evaluate the potential role of equid herpesviruses (EHV) in several occurrences of respiratory disorders in 661 horses. Of 785 bronchoalveolar or tracheal lavage fluid samples submitted for analysis, 20 were positive for EHV-5 DNA by sequential analysis of the consensus PCR product. Nineteen of those samples were confirmed using a specific EHV-5 PCR. No particular changes in cytological profile could be associated with the detection of EHV-5 in contrast to suggestions in previous reports of natural or experimental respiratory viral infections in horses or ponies. This is the first description of EHV-5 isolation in equine respiratory fluids in Europe, but further investigations are needed to determine the potential pathogenic role of this gammaherpesvirus in the horse. [less ▲]

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See detailEpithelial expression of mRNA and protein for IL-6, IL-10 and TNF-alpha in endobronchial biopsies in horses with recurrent airway obstruction.
Riihimäki, Miia; Raine, Amanda; Pourazar, Jamshid et al

in BMC Veterinary Research (2008), 4

BACKGROUND: The aim of this study was to evaluate the contribution of bronchial epithelium to airway inflammation, with focus on mRNA and protein expression of cytokines of innate immunity IL-6, IL-10 and ... [more ▼]

BACKGROUND: The aim of this study was to evaluate the contribution of bronchial epithelium to airway inflammation, with focus on mRNA and protein expression of cytokines of innate immunity IL-6, IL-10 and TNF-alpha, in horses with Recurrent Airway Obstruction (RAO) during exacerbation and in remission. RESULTS: Despite marked clinical and physiologic alterations between exacerbation and after remission in the RAO horses no differences were detected in either cytokine mRNA or protein levels. Moreover, the expression of investigated cytokines in RAO horses on pasture did not differ from controls.In comparing real-time PCR analysis to results of immunohistochemistry only IL-10 mRNA and protein levels in RAO horses on pasture were significantly correlated (rs = 0.893, p = 0.007). Curiously, in controls examined on pasture the TNF-alpha protein level was positively correlated to IL-10 mRNA expression (rs = 0.967, p = 0.007) and negatively correlated to IL-6 mRNA expression (rs = -0.971, p = 0.001). CONCLUSION: Given the complementary relationship of assessing cytokines directly by immunohistochemistry, or indirectly by PCR to mRNA, the lack of significant changes in either mRNA or protein levels of IL-6, IL-10 or TNF-alpha mRNA in RAO horses in exacerbation suggests that these particular cytokines in bronchial tissue may not play a substantive role in the active inflammation of this disease. To support this contention further studies examining time dependency of expression of IL-6, IL-10 or TNF-alpha are needed, as is expansion of the range of cytokines to include other key regulators of airway inflammation. [less ▲]

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See detailUsing a human microarray to highlight new genes of interest for a better understanding of molecular mechanisms that underpin the physiopathology of heaves
Ramery, Eve ULg; Closset, Rodrigue; Bureau, Fabrice ULg et al

in Proceedings: Plant and Animal Genome Conference, Equine Workshop, San Diego (2008)

Environmental causes of heaves are well described, but the molecular mechanisms of the disease remain unclear. Using reverse transcription polymerase chain reaction (RT-PCR), disparate results have been ... [more ▼]

Environmental causes of heaves are well described, but the molecular mechanisms of the disease remain unclear. Using reverse transcription polymerase chain reaction (RT-PCR), disparate results have been obtained concerning cytokines expression profile. cDNA microarray appears to be so far the platform of choice for massively parallel gene expression profiling and provides a good tool for exploratory research. However, equine-specific microarrays are not yet available on the market. Because they are commercially available, highly specific and well annotated, human and mouse large-scale microarrays are an exploratory alternative to equine-specific microarrays. In the present study, the purpose was to highlight new targets not previously related to the disease and able to improve our understanding of the molecular mechanisms of the disease. A human microarray was used to study gene expression in nucleated cells originating from peripheral blood and bronchoalveolar lavage fluid in heaves-affected horses. With a four-fold cut-off, a total of 46 candidates were identified with differentially regulated genes between heaves-affected horses and controls. Based on their documented function, five of these genes were selected for the real-time quantitative RT-PCR (RT-qPCR) validation procedure: CYBB, BTG1, MARCKS, PTX3 and PTPRC. The RT-qPCR results confirmed those obtained with the microarray, pointing out these genes as new directions for future experiments. However, the human microarray failed to detect the presence of IL-1beta and Il-8, otherwise confirmed by RT-qPCR, and the expression profile of the disease could not be obtained [less ▲]

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See detailEtude de l'administration par inhalation de cefquinome chez le cheval sain
Art, Tatiana ULg; Van Erk, E.; Ramery, Eve ULg et al

in Pratique Vétérinaire Equine (2008), 40

Cefquinome aerosol is sometimes used in horse suffering from respiratory infections. However, harmlessness and validity of the method has never been studied. This work aimed at controlling the lack of ... [more ▼]

Cefquinome aerosol is sometimes used in horse suffering from respiratory infections. However, harmlessness and validity of the method has never been studied. This work aimed at controlling the lack of pulmonary effects of cefquinome when administered through inhalation in healthy horses and at comparing the cefquinome concentrations obtained in broncho-alveolar lavage after aerosol, intramuscular and intravenous administrations. A single aerosol of cefquinome did not induce any detectable side effect in healthy horses and allowed to obtain broncho-alveolar concentrations higher than obtained with intravenous and intramuscular injection. These results should now be completed by further studies, especially on horses suffering from respiratory disease and bronchial hyperreactivity [less ▲]

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See detailThe oxidant/antioxidant equilibrium in horses
Kirschvink, Nathalie; de Moffarts, Brieuc; Lekeux, Pierre ULg

in Veterinary Journal (2008), 177(2), 178-191

Since "free radical research" started in 1954, understanding the role of oxidants and antioxidants in physiological and pathological conditions has increased continuously. Oxidants are essentially ... [more ▼]

Since "free radical research" started in 1954, understanding the role of oxidants and antioxidants in physiological and pathological conditions has increased continuously. Oxidants are essentially generated by metabolic enzymes, inflammatory cells and mitochondrial electron leakage; they are indispensable for the cellular redox regulation and may, under certain conditions, have a pro-inflammatory stimulatory role. Endogenous and exogenous antioxidants counterbalance the oxidative processes and so maintain the oxidant/antioxidant equilibrium. Excessive oxidant generation or antioxidant insufficiency can lead to oxidative stress. The aims of this review are: (1) to provide an insight into the concept of the oxidant/antioxidant equilibrium by briefly introducing the oxidant and the antioxidant systems; (2) to describe how the oxidant/antioxidant equilibrium or oxidative stress can be evaluated in horses, and (3) to summarise current knowledge about oxidative stress in equine medicine and equine exercise physiology. [less ▲]

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See detailPartial divergence of cytokine mRNA expression in bronchial tissues compared to bronchoalveolar lavage cells in horses with recurrent airway obstruction.
Riihimaki, M.; Raine, Amanda; Art, Tatiana ULg et al

in Veterinary Immunology and Immunopathology (2008), 122(3-4), 256-64

The aim of this study was to investigate mRNA levels of cytokines in bronchial epithelium in horses with recurrent airway obstruction (RAO) during acute crisis and remission. Additionally, cytokine mRNA ... [more ▼]

The aim of this study was to investigate mRNA levels of cytokines in bronchial epithelium in horses with recurrent airway obstruction (RAO) during acute crisis and remission. Additionally, cytokine mRNA levels in endobronchial biopsies and bronchoalveolar lavage (BAL) cells were compared. Seven RAO horses were examined while in respiratory crisis following provocation and again while in remission after 2 months on pasture, during which time six healthy horses on pasture were also examined. Quantitative real-time PCR (RT-PCR) was used to assess mRNA expression for cytokines IL-5, IL-6, IL-8, IL-10, IL-17 and transforming growth factor beta1 (TGF-beta1) in endobronchial biopsies and bronchoalveolar lavage. Expression of IL-8 mRNA was significantly upregulated during crisis in both endobronchial biopsies and BAL cells (p=0.036), while there was a similar trend for upregulation of IL-10 mRNA only in BAL cells that approached significance (p=0.059). Moreover, during crisis the expression of IL-8 mRNA in BAL cells was positively correlated to relative IL-6 mRNA expression (r(s)=0.971, p=0.001) and bronchial epithelial expression of IL-10 and TGF-beta1 mRNA were positively correlated (r(s)=0.943, p=0.005). In comparing the relationship of mRNA expression in BAL to biopsy in individual RAO horses, there was a positive correlation with IL-6 to IL-8 mRNA expression in BAL during respiratory crisis (r(s)=0.971, p=0.001) that also correlated positively with IL-8 expression in biopsies on pasture (r(s)=0.986, p<0.0001 for both). Regarding RAO horses at pasture versus controls neither the cytokine mRNA levels in endobronchial biopsy nor in BAL cells differed significantly. These results further support previous findings that IL-8 mRNA in both BAL cells and bronchial epithelium is upregulated in RAO horses during crisis. However, apart from IL-8, it appears that expression of other cytokines, including IL-5, IL-6, IL-10, IL-17 and TGF-beta1 in bronchial epithelium does not necessarily mirror cytokine expression in BAL cells in individual horses with RAO. Accordingly, examination of markers of inflammation in endobronchial tissue provides complementary but not necessarily identical information to that obtained in BAL cells. Given the potential for repeated sampling over time bronchial biopsy can serve as an invaluable additional tool for investigation of time-dependent changes in inflammatory process in this animal model of asthma. [less ▲]

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See detailLe stress oxydant est modifié en fonction du statut clinique chez les trotteurs à l’entraînement
Van Erck, Emmanuelle; Lekeux, Pierre ULg; Kirschvink, N.

in 36èmes Journées AVEF (2008)

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See detailLes myopathies subcliniques constituent-elles une cause d’intolérance à l’effort ?
Van Erck, Emmanuelle; Lekeux, Pierre ULg

in 36èmes Journées AVEF (2008)

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See detailLung interstitial macrophages prevent lipopolysaccharide-triggered T helper type 2 responses to harmless inhaled antigens
Bedoret, D.; Wallemacq, Hugues ULg; Marichal, Thomas ULg et al

in Proceedings of the Annual BIS-meeting (2008)

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See detailExpression génique et médecine vétérinaire
Ramery, Eve ULg; Van Erck, Emmanuelle ULg; Bureau, Fabrice ULg et al

in Proceedings des 36èmes Journées AVEF (2008)

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See detailHow transcriptomic studies may help to improve the control of bovine diseases : an example with calf pneumonia and endotoxemia
Wallemacq, Hugues ULg; Ramery, Eve ULg; Bureau, Fabrice ULg et al

in Proceedings: XXVth Jubilee World Buiatrics Congress (2008)

Global change in genes expression induced by pathological processes can now be analysed in cattle by new tools called microarrays. These transcriptomic studies may help to better understand the ... [more ▼]

Global change in genes expression induced by pathological processes can now be analysed in cattle by new tools called microarrays. These transcriptomic studies may help to better understand the pathophysiological mechanisms responsible for the disease and may therefore contribute to develop more efficient preventive and curative strategies. An example is given with a model of calf pneumonia and endotoxemia [less ▲]

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See detailEvaluation de la condition physique chez le cheval d’endurance : comparaison d’un test de terrain adapté et d’un test sur tapis roulant
Fraipont, Audrey ULg; Van Erck, Emmanuelle; Toussaint, Marie et al

in 36èmes Journées AVEF (2008)

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