References of "Lekeux, Pierre"
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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 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)

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See detailLaboratory findings in respiratory fluids of the poorly-performing horse
Richard, Eric ULg; Fortier, Guillaume; Lekeux, Pierre ULg et al

in Veterinary Journal (2009)

Any disorder impairing a performance horse’s ability to ventilate its lungs and exchange oxygen compromises exercise performance in any discipline. Since bronchoalveolar lavage was described in horses in ... [more ▼]

Any disorder impairing a performance horse’s ability to ventilate its lungs and exchange oxygen compromises exercise performance in any discipline. Since bronchoalveolar lavage was described in horses in the early 1980s, laboratory evaluation of respiratory fluids, along with clinical and functional assessment of the respiratory system, has become a relevant step in the diagnosis of respiratory disease affecting performance. The aim of this review is to provide objective information to assist clinicians in interpreting laboratory findings by (1) summarising published cytological references values in both clinically healthy horses and those with various airway diseases, (2) assessing the influence of physiological circumstances, such as exercise, on the cytological evaluation, (3) discussing the relationship between cytological and microbiological analyses, clinical signs and respiratory function, and (4) suggesting how this latter relationship may affect performance. [less ▲]

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See detailComment investiguer la contre-performance d’origine médicale : de la clinique au laboratoire
Richard, Eric; Pitel, P. H.; Fortier, G. et al

in 35ème Journée de la Recherche équine (2009)

Clinical affections of the locomotor and respiratory systems are the two main causes of poor performance in sport horses. Nevertheless, each subclinical affection of any system implicated in the oxygen ... [more ▼]

Clinical affections of the locomotor and respiratory systems are the two main causes of poor performance in sport horses. Nevertheless, each subclinical affection of any system implicated in the oxygen system (respiratory, cardiovascular, blood, muscular and metabolic) may also become a limiting factor concerning the athletic capacities of the horse. A systematic medical examination of the horse, combining ail the clinical and laboratory exams, is thus necessary in order to establish a precise and comprehensive diagnosis regarding the different affections. The objectives of this communication are therefore to present the different methods currently available for the practitioner as well as the techniques recently developed for horses. The complementarity of the different clinical and laboratory exams, as well as the ideal moment for performing each test are clarified in order to accurately determine the different causes of poor performance as well as their functional repercussions [less ▲]

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See detailPourquoi examiner le cheval à l’effort ?
Van Erck, Emmanuelle; Lekeux, Pierre ULg

in 35ème Journée de la Recherche équine (2009)

Examination of the horse during daily work is essential to follow-up his athletic préparation, however a good level of expérience is required to judge if he is ready to perform in compétition. Beyond thé ... [more ▼]

Examination of the horse during daily work is essential to follow-up his athletic préparation, however a good level of expérience is required to judge if he is ready to perform in compétition. Beyond thé subjective estimation of his behaviour and progress, objective parameters can be measured to evaluate his athletic capacity, level of fitness and health. Simple exercise tests can be integrated to thé horse's regular work schedule and parameters such as speed, heart rate and cardio-respiratory recovery may be readily monitored and compared during thé course of thé season. More sophisticated tests allow investigating exercise physiology of thé horse during exertion and thé way he tolerates and adapts to physical strain. It also allows early détection of subclinical diseases liable to impair performance. Like in human sports medicine, treadmill tests represent a safe investigation tool that is particularly well adapted to examining horses during exercise and helps diagnose one or several causes of poor performance, as many ancillary examinations may be implemented. [less ▲]

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See detailEffects of betamethasone on inflammation and emphysema induced by cadmium nebulisation in rats
Fievez, Laurence ULg; Kirschvink, N.; Zhang, Wenhui H. et al

in European Journal of Pharmacology (2009), 606(1-3), 210-214

Cadmium (Cd) induces centrilobular emphysema and is suspected to contribute to tobacco related lung diseases as chronic obstructive pulmonary disease (COPD). This study aimed to check whether the ... [more ▼]

Cadmium (Cd) induces centrilobular emphysema and is suspected to contribute to tobacco related lung diseases as chronic obstructive pulmonary disease (COPD). This study aimed to check whether the inflammatory process observed in rats exposed to nebulised Cd is resistant to betamethasone as observed in COPD and to determine the influence of this drug on airspace enlargement together with the MMP-2-9/TIMP-1-2 imbalance. Our results showed that betamethasone induced emphysema by itself in healthy rats. Moreover, pre-treatment of rats with betamethasone could only partially modulate the increase in bronchoalveolar lavage fluid cell counts and the absence of preventive effect of this compound against emphysema development is associated with its inability to rebalance the MMP-2-9/TIMP-1-2 ratio. [less ▲]

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See detailSyndrome d'inflammation trachéale : évaluation clinique et bactériologique
Richard, Eric ULg; Maillard, K.; Dupuis, Marie-Capucine ULg et al

in Pratique Vétérinaire Equine (2009), 41(162), 45-49

Lower airway inflammation is a frequent cause of poor-performance in hors e s .An association between inflammation and bacterial isolation in tracheal wash fluid has previously been found ; bacterial ... [more ▼]

Lower airway inflammation is a frequent cause of poor-performance in hors e s .An association between inflammation and bacterial isolation in tracheal wash fluid has previously been found ; bacterial counts were neve rtheless not defined.The aims of this study were to qualitatively and quantitatively compare tracheal bacterial flora of French Trotters with tracheal inflammation (SIT) and control horses (CTL), and evaluate association between endoscopic, cytological and microbiological evaluation of the trachea. Neutrophil percentage in tracheal wash was significantly different between groups whereas tracheal mucus accumulation was not. No significant difference was found between groups for neither percentage of respectively sterile samples or percentage pathogenic bacteria being isolated. Bacterial counts in SIT group were however 10 to 200 times higher than in the CTL group.This study suggests that isolation of pathogenic bacteria alone do not allow estimation of the level of airway inflammation; whereas severe tracheal inflammation may be present in absence of any bacteriological infection [less ▲]

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See detailInfluence of subclinical inflammatory airway disease on equine respiratory function evalueated by impulse oscillometry
Richard, Eric ULg; Fortier, Guillaume; Denoix, Jean-Marie et al

in Equine Veterinary Journal (2009), 41(4), 384-389

Reasons for performing study: Inflammatory airway disease (IAD) is a nonseptic condition of the lower respiratory tract. Its negative impact on respiratory function has previously <br /><br />been ... [more ▼]

Reasons for performing study: Inflammatory airway disease (IAD) is a nonseptic condition of the lower respiratory tract. Its negative impact on respiratory function has previously <br /><br />been described using either forced expiration or forced oscillations techniques. However, sedation or drug-induced bronchoconstriction were usually required. The impulse <br /><br />oscillometry system (IOS) is a noninvasive and sensitive respiratory function test validated in horses, which could be useful to evaluate IAD-affected horses without further <br /><br />procedures. <br /><br />Objectives: To determine the sensitivity of IOS in detecting alterations of the respiratory function in subclinically IAD-affected horses without inducing bronchoprovocation and to characterise their respiratory impedance according to frequency for each respiratory phase. <br /><br />Methods: Pulmonary function was evaluated at rest by IOS in 34 Standardbred trotters. According to the cytology of bronchoalveolar lavage fluid (BALF), 19 horses were defined <br /><br />as IAD-affected and 15 horses were used as control (CTL). Total respiratory resistance (Rrs) and reactance (Xrs) from 1–20 Hz as well as their inspiratory and expiratory <br /><br />components were compared between groups. <br /><br />Results: A significant increase of Rrs at the lower frequencies (R1–10 Hz) as well as a significant decrease of Xrs beyond 5 Hz (X5–20 Hz) was observed in IAD compared to CTL horses. IOS-data was also significantly different between inspiration and expiration in IAD-affected horses. In the whole population, both BALF eosinophil and mast cell counts were <br /><br />significantly correlated with IOS measurements. <br /><br />Conclusions: Functional respiratory impairment may be measured, even in the absence of clinical signs of disease. In IAD-affected horses, the different parameters of respiratory <br /><br />function (Rrs or Xrs) may vary depending on the inflammatory cell profiles represented in BALF. <br /><br />Potential relevance: Impulse oscillometry could be used in a routine clinical setting as a noninvasive method for early detection of subclinical respiratory disease and of the results <br /><br />of treatment in horses. [less ▲]

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