References of "Lekeux, Pierre"
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See detailSubclinical diseases underlying poor performance in endurance horses: diagnostic methods and predictive tests.
Fraipont, Audrey ULg; Van Erck, E.; Ramery, Eve ULg et al

in Veterinary Record : Journal of the British Veterinary Association (2011), 169(6), 154

Thirty-eight endurance horses underwent clinical and ancillary examinations, including haematological and biochemical evaluation, standardised exercise tests both on a treadmill and in the field, Doppler ... [more ▼]

Thirty-eight endurance horses underwent clinical and ancillary examinations, including haematological and biochemical evaluation, standardised exercise tests both on a treadmill and in the field, Doppler echocardiography, impulse oscillometry, video endoscopy and collection of respiratory fluids. All of the examined poorly performing horses were affected by subclinical diseases, and most of them had multiple concomitant disorders. On the contrary, the well-performing horses were free of any subclinical disease. The most frequently diagnosed diseases were respiratory disorders, followed by musculoskeletal and cardiac problems. Poor performers exhibited lower speeds at blood lactate concentration of 4 mmol/l (VLA4) and at heart rates of 160 (V160) and 200 bpm (V200) on the treadmill and in the field, as well as slower recovery of heart rate. [less ▲]

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See detailSirtuin 1 Promotes Th2 Responses and Airway Allergy by Repressing Peroxisome Proliferator-Activated Receptor-γ Activity in Dendritic Cells
Legutko, Agnieszka; Marichal, Thomas ULg; Fievez, Laurence ULg et al

in Journal of Immunology (2011), 187(9), 4517-4529

Sirtuins are a unique class of NAD+-dependent deacetylases that regulate diverse biological functions such as aging, metabolism, and stress resistance. Recently, it has been shown that sirtuins may have ... [more ▼]

Sirtuins are a unique class of NAD+-dependent deacetylases that regulate diverse biological functions such as aging, metabolism, and stress resistance. Recently, it has been shown that sirtuins may have anti-inflammatory activities by inhibiting proinflammatory transcription factors such as NF-κB. In contrast, we report in this study that pharmacological inhibition of sirtuins dampens adaptive Th2 responses and subsequent allergic inflammation by interfering with lung dendritic cell (DC) function in a mouse model of airway allergy. Using genetic engineering, we demonstrate that sirtuin 1 represses the activity of the nuclear receptor peroxisome proliferator-activated receptor-γ in DCs, thereby favoring their maturation toward a pro-Th2 phenotype. This study reveals a previously unappreciated function of sirtuin 1 in the regulation of DC function and Th2 responses, thus shedding new light on our current knowledge on the regulation of inflammatory processes by sirtuins. [less ▲]

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See detailInterferon Response Factor 3 is required for airway allergy to house dust mite in mice
Marichal, Thomas ULg; Bedoret Denis; Mesnil, Claire ULg et al

in Short Book of the Annual Congress of the Euopean Respiratory Society (ERS), Barcelone (2010, September)

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See detailGenomic expression evaluation: introduction and perspectives
Ramery, Eve ULg; Bureau, Fabrice ULg; Guyot, Hugues ULg et al

Conference (2010, July)

In a way, disease could be considered as the result of gene expression deregulation. Knowing what genes are expressed in a particular cell or tissue and how they are regulated allow to better understand ... [more ▼]

In a way, disease could be considered as the result of gene expression deregulation. Knowing what genes are expressed in a particular cell or tissue and how they are regulated allow to better understand disease mechanisms. Transcriptomic is the study of the expression of the entire genome. This technical challenge has been rendered possible as different species’ genomes began to be sequenced. Several techniques have rendered efficient this process of measuring simultaneously the expression level of a large number of genes. To date, micro-array technology is probably the best known. However, with the development of more affordable techniques, sequencing/ resequencing could compete with microarrays in the future. All together, these techniques open new ways for early diagnosis and prognosis for the practioner ‘in the field’. [less ▲]

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See detailRelease and innate detection of hot cell DNA mediates the adjuvant effects of aluminium salts on adaptive responses.
Marichal, Thomas ULg; Ohata, Keichii; Bedoret, Denis et al

Conference (2010, February)

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See detailCharacterization of pentraxin 3 in the horse and its expression in airways.
Ramery, Eve ULg; Fievez, Laurence ULg; Fraipont, Audrey ULg et al

in Veterinary Research (2010), 41(2), 18

The long pentraxin 3 (PTX3) plays an important role in host defence and its over-expression may contribute to airway injury. The aim of the present study was therefore to characterize in more detail PTX3 ... [more ▼]

The long pentraxin 3 (PTX3) plays an important role in host defence and its over-expression may contribute to airway injury. The aim of the present study was therefore to characterize in more detail PTX3 and its expression in the horses airway. Six healthy horses and six horses affected by recurrent airway obstruction (R.A.O.) were submitted to a dusty environment challenge. PTX3 DNA and cDNA were cloned and sequenced. PTX3 expression was evaluated by RT-qPCR, western blotting and immuno-histochemistry in bronchoalveolar lavage fluid (BALF) cells, BALF supernatant and bronchial epithelial cells. An alternative splicing of the second exon of PTX3 occurred, resulting in two forms of the protein: spliced (32 kDa) and full length (42 kDa). PTX3 was detected in BALF macrophages, neutrophils and bronchial epithelial cells. It was over-expressed in the BALF supernatant from R.A.O.-affected horses in crisis. However, dust was unable to induce PTX3 in BALF cells ex vivo, indicating that dust is an indirect inducer of PTX3. Dust exposure in-vivo induced PTX3 in BALF macrophages but there was no significant difference between healthy and R.A.O.-affected horses. Conversely, PTX3 was over-expressed in the bronchial epithelial cells from R.A.O-affected horses in crisis. These data indicate a differential regulatory mechanism in inflammatory and bronchial epithelial cells and offer therapeutically interesting perspectives. [less ▲]

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See detailViral induction of Zac1b through TLR3- and IRF3-dependent pathways
Warzée, Barbara ULg; Mesnil, Claire ULg; Hober, D. et al

in Molecular Immunology (2010), 48(1-3), 119-127

Zinc finger protein regulator of apoptosis and cell cycle arrest (Zac1) is a transcription factor able to induce apoptosis or cell cycle arrest through independent pathways. In spite of the important ... [more ▼]

Zinc finger protein regulator of apoptosis and cell cycle arrest (Zac1) is a transcription factor able to induce apoptosis or cell cycle arrest through independent pathways. In spite of the important potential functions attributed to Zac1, little is known of its physiological regulation and biological function. We discovered that variant Zac1b was expressed in murine embryonic fibroblasts (MEFs) treated with polyriboinosinic polyribocytidylic acid [poly(I:C)], a synthetic double-stranded RNA. This regulation occurred mainly through Toll-Like Receptor 3 (TLR3)- and Interferon Regulatory Factor 3 (IRF3)-dependent pathways. As TLR3 and IRF3 are central activators of antiviral immunity, we hypothesized that Zac1 may be implicated in antiviral responses. In line with this notion, we observed that Zac1b was expressed in MEFs infected with Encephalomyocarditis virus (EMCV). We also observed that Zac1-deficient MEFs were less sensitive to EMCV-induced cell death than wild-type MEFs. However, Zac1 gene inactivation had no effect on the survival of mice infected with EMCV. In conclusion, this study describes for the first time a transcriptional regulation of Zac1b, induced by synthetic dsRNA and RNA viruses, the functional significance of which remains to be further investigated. [less ▲]

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See detailInterferon Response Factor 3 is essential for house dust mite-induced airway allergy
Marichal, Thomas ULg; Bedoret, Denis; Mesnil, Claire ULg et al

in Journal of Allergy and Clinical Immunology (The) (2010), 126(4), 836-844

IRF3, mainly known as a central orchestrator of antiviral responses, is required for proallergic functions of dendritic cells in response to aeroallergens. Thus, this study demonstratively identifies a ... [more ▼]

IRF3, mainly known as a central orchestrator of antiviral responses, is required for proallergic functions of dendritic cells in response to aeroallergens. Thus, this study demonstratively identifies a new pathway potentially implicated in the etiology of airway allergy [less ▲]

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See detailSubclinical diseases affecting performance in Standardbred trotters: Diagnostic methods and predictive parameters
Richard, Eric ULg; Fortier, Guillaume; Pitel, Pierre-Hugues et al

in Veterinary Journal (2010), 184(3), 282-289

The objectives of this study were to determine the prevalence of sub-clinical diseases in poorly-performing Standardbred horses, compare their physiological response to exercise with control horses, and ... [more ▼]

The objectives of this study were to determine the prevalence of sub-clinical diseases in poorly-performing Standardbred horses, compare their physiological response to exercise with control horses, and identify predictive parameters of poor-performance. Fifty horses underwent thorough clinical and ancillary examinations, including haematological and biochemical evaluation, Doppler echocardiography, standardised exercise tests (SETs) on both treadmill and racetrack, treadmill video-endoscopy and collection of respiratory fluids. Most of the poorly-performing horses exhibited many concomitant diseases. The most frequently diagnosed problems involved the lower and upper respiratory tract and the musculoskeletal system. Poor-performers had lower speeds at a blood lactate (LA) concentration of 4 mmol/L (VLA4) and a heart rate (HR) of 200 bpm (V200) on treadmill and racetrack, as well as lower values for haematological parameters, plasma angiotensin-converting enzyme and antioxidants, compared to control horses. Problems of the respiratory system were the most frequently diagnosed sub-clinical diseases affecting performance. SETs, together with some blood markers, may be useful as a non-specific diagnostic tool for early detection of diseases that may affect performance. [less ▲]

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See detailPulmonary function, airway cytology and bronchoalveolar lavage fluid drug concentration after aerosol administration of cefquinome to horses
Art, Tatiana ULg; Ramery, Eve ULg; Fraipont, Audrey ULg et al

in Equine Veterinary Education (2010), 22(9), 473-479

The administration of antibiotics by aerosol to horses suffering from respiratory infections may partially circumvent the limitations of antimicrobial therapy, e.g. large injection volumes, low ... [more ▼]

The administration of antibiotics by aerosol to horses suffering from respiratory infections may partially circumvent the limitations of antimicrobial therapy, e.g. large injection volumes, low bioavailability and risk of diarrhea. Only injectable formulations are available currently and usually contain other substances that could irritate the mucosa and induce coughing and bronchospasm. In addition, the quality of the aerosol, particularly in terms of the delivery of antibiotics to the deep parts of the lung, is unknown. Although used under field conditions, cefquinome delivered by aerosol has never been studied in horses. This study examined the safety of cefquinome injectable solution, administered by aerosol at a dose of 225 mg/inhalation to 7 healthy horses, by assessing (1) pulmonary function before and 15 min after a single inhalation, at the first day (Day 1) and the fifth day (Day 5) of a 5 day period treatment; and (2) the inflammatory status of the lung, i.e. percentage neutrophils and myeloperoxidase concentration, based on bronchoalveolar lavage (BAL) at D1 and D5. In addition, cefquinome concentrations were measured in bronchoalveolar lavage fluid after aerosol, intravenous (i.v.) and intramuscular (i.m.) administrations. A single aerosol of cefquinome injectable solution did not induce any immediate nor delayed pulmonary side effects in healthy horses and produced cefquinome concentrations in bronchoalveolar lavage (BAL) within 30 min that were higher than the minimal inhibitory concentration of the main equine respiratory pathogens. These results should stimulate further studies, especially in horses suffering from bronchial hyper-reactivity. Aerosol delivery of antibiotics may well have a role in equine therapeutics. [less ▲]

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See detailLa vaccination contre les mammites à Staphylococcus aureus chez la vache laitière
Wallemacq, Hugues; Girard, B.; Lekeux, Pierre ULg et al

in Annales de Médecine Vétérinaire (2010), 154(1), 16-29

Staphylococcus (S.) aureus is a major pathogen for mastitis in dairy cattle. In most cases, S. aureus causes long-lasting subclinical and chronic bovine mastitis and leads to significant economic losses ... [more ▼]

Staphylococcus (S.) aureus is a major pathogen for mastitis in dairy cattle. In most cases, S. aureus causes long-lasting subclinical and chronic bovine mastitis and leads to significant economic losses by reducing the quantity and the quality of the milk produced. The pathogenesis of S. aureus mastitis includes the ability to persist within host cells and involves multiple virulence factors including toxins, surface proteins and polysaccharides. The numerous vaccines that have been developed induce a specific immune response against these different factors. These different vaccine approaches are described and classified depending on the target antigen used. Moreover, some recent vaccine strategies against human S. aureus infections are also discussed and could eventually be used for the design of new bovine vaccines. Although most of bovine vaccines induce specific humoral response, to date, no vaccine has been described to protect efficiently against experimental and naturally occurred bovine S. aureus mastitis. In conclusion, this type of immune response and the broad antigenic variability of S. aureus strains can partially explain the lack of protection observed during most of vaccine trials. [less ▲]

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See detailEquine gammaherpesviruses : pathogenesis, epidemiology and diagnosis
Fortier, Guillaume; Van Erck, Emmanuelle ULg; Pronost, Stéphane et al

in Veterinary Journal (2010), 186

Equine gammaherpesviruses (cEHV) have been widely studied over the past 45 years and many isolates have been characterised. Despite this, the diagnosis of cEHV infection remains difficult to establish as ... [more ▼]

Equine gammaherpesviruses (cEHV) have been widely studied over the past 45 years and many isolates have been characterised. Despite this, the diagnosis of cEHV infection remains difficult to establish as its clinical manifestations lack specificity, ranging from mild respiratory signs in a small number of animals to outbreaks in large groups of young horses. This review focuses on the epidemiology, pathogenesis, clinical manifestations and diagnosis of equine herpesvirus (EHV)-2 and -5 infections, as well as on the genetic variation of these viruses. Study of these variations has resulted in hypotheses relating to viral re-infection and re-activation. Interestingly, the viruses were found to contain genetic sequences identical to those of eukaryotic cells which are considered central to the development of viral latency through interfering with host immune and inflammatory responses. Future molecular biological studies will further elucidate the virulence mechanisms of these equine pathogens [less ▲]

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See detailVeterinary education curriculum: basic sciences
Lekeux, Pierre ULg

Conference given outside the academic context (2009)

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See detailA crucial role forlung interstitial macrophages in preventing airway allergy
Bedoret, Denis; Wallemacq, Hugues ULg; Marichal, Thomas ULg et al

in Short book of the Annual Congress of the European Respiratory Society (ERS), Vienne (2009)

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See detailLung interstitial macrophages prevent the development of respiratory allergy
Bedoret, D.; Wallemacq, Hugues ULg; Marichal, Thomas ULg et al

in Proceedings of The Keystone Symposia: Allergy and Asthma. Keystone, Colorado, USA (2009)

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See detailInterstitial macrophages are essential for maintaining immune homeostasis in the lung
Bedoret, Denis; Wallemacq, Hugues ULg; Marichal, Thomas ULg et al

in Proceedings of The Allergy & Asthma Symposium: Bridging Innate and Adaptive Immunity (2009)

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See detailLung interstitial macrophages alter dendritic cell functions to prevent airway allergy in mice
Bedoret, Denis ULg; Wallemacq, Hugues ULg; Marichal, Thomas ULg et al

in Journal of Clinical Investigation (2009), 119(12), 3723-38

The respiratory tract is continuously exposed to both innocuous airborne antigens and immunostimulatory molecules of microbial origin, such as LPS. At low concentrations, airborne LPS can induce a lung DC ... [more ▼]

The respiratory tract is continuously exposed to both innocuous airborne antigens and immunostimulatory molecules of microbial origin, such as LPS. At low concentrations, airborne LPS can induce a lung DC-driven Th2 cell response to harmless inhaled antigens, thereby promoting allergic asthma. However, only a small fraction of people exposed to environmental LPS develop allergic asthma. What prevents most people from mounting a lung DC-driven Th2 response upon exposure to LPS is not understood. Here we have shown that lung interstitial macrophages (IMs), a cell population with no previously described in vivo function, prevent induction of a Th2 response in mice challenged with LPS and an experimental harmless airborne antigen. IMs, but not alveolar macrophages, were found to produce high levels of IL-10 and to inhibit LPS-induced maturation and migration of DCs loaded with the experimental harmless airborne antigen in an IL-10-dependent manner. We further demonstrated that specific in vivo elimination of IMs led to overt asthmatic reactions to innocuous airborne antigens inhaled with low doses of LPS. This study has revealed a crucial role for IMs in maintaining immune homeostasis in the respiratory tract and provides an explanation for the paradox that although airborne LPS has the ability to promote the induction of Th2 responses by lung DCs, it does not provoke airway allergy under normal conditions. [less ▲]

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See detailHerpesviruses in respiratory liquids of horses : putative implication in airway inflammation and association with cytological features
Fortier, Guillaume ULg; Van Erck, Emmanuelle ULg; Fortier, Christine et al

in Veterinary Microbiology (2009), 139

The objectives of this study were to estimate the prevalence and the potential role of equine herpesviruses (EHVs) detection in both bronchoalveolar lavage (BAL) and tracheal wash (TW). The population ... [more ▼]

The objectives of this study were to estimate the prevalence and the potential role of equine herpesviruses (EHVs) detection in both bronchoalveolar lavage (BAL) and tracheal wash (TW). The population included a control group (CTL; 37 TW and 25 BAL) and a pathological group (PAT; 259 TW and 387 BAL), including horses either suffering from respiratory diseases including syndrome of tracheal inflammation, inflammatory airway disease, recurrent airway obstruction, or submitted to respiratory investigation because of exercise intolerance or poor performance. Each respiratory liquid was submitted to a standardised cytological analysis, mentioning the morphological abnormalities of exfoliated epithelial cells (ECAb) and ciliocytophthoria (CCPh) as markers of potential viral infection, as well as PCR assays including a consensus PCR and virus-specific PCR for both equine alphaherpesviruses (EHV-1; EHV-4) and gammaherpesviruses (EHV-2; EHV-5). The EHV infections were more prevalent in the TW of PAT group (P = 0.004), with the highest prevalence being for EHV-2 (P = 0.006). The EHV detection in BALs was not significantly different between groups. The EHVs detection in TW was correlated to the polymorphonuclear neutrophil (PMN) counts in the respiratory liquid but not with CCPh or ECAb. CCPh or ECAb were associated with both consensus PCR and EHV-2 and EHV-5 virus-type PCR in the BAL only. The significant detection of EHVs in the TWof PAT group in association with the PMN increased counts could lead to further investigations about their putative role in equine syndrome of tracheal inflammation [less ▲]

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See detailLe microdamier: un outil du futur pour le diagnostic de l’inflammation ?
Mignot, Clémence ULg; Fraipont, Audrey ULg; Richard, Eric et al

Poster (2009)

Detailed reference viewed: 47 (19 ULg)