References of "Desmecht, Daniel"
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See detailFlow cytometric enumeration of parasitaemia and haematologic changes in trypanosoma-infected mice.
Antoine-Moussiaux, Nicolas ULg; Saerens, Dirk; Desmecht, Daniel ULg

in Acta Tropica (2008), 107(2), 139-44

African trypanosomiasis is a severe parasitic disease affecting both man and livestock. It is crucial to expand our fundamental knowledge of the intimate interactions between trypanosomes and their ... [more ▼]

African trypanosomiasis is a severe parasitic disease affecting both man and livestock. It is crucial to expand our fundamental knowledge of the intimate interactions between trypanosomes and their vertebrate hosts in order to develop new and efficient control strategies. The mouse model of trypanosomiasis is the most popular for research purposes because of all the logistic advantages of using this species. Studies of any aspect of trypanosomiases in the mouse systematically require the quantification of some phenotypic traits which translate its degree of resistance/susceptibility to the disease, as blood cell counts. The present study presents a methodological approach combining everyday microsampling of tail blood and its analysis by flow cytometry. The technical options and conditions permitting a fast, reliable and reproducible daily quantification of erythrocyte, reticulocyte, leucocyte and trypanosome counts in the inoculated mouse were established. The protocol proposed allows the multiplication of blood samplings without being exposed to the time-consuming constraint of visual countings, without causing iatrogenic blood cell alterations in the mouse and without requiring specific anti-trypanosome antibodies. [less ▲]

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See detailPathologie de l'infection par Trypanosoma evansi
Antoine-Moussiaux, Nicolas ULg; Desmecht, Daniel ULg

in Annales de Médecine Vétérinaire (2008), 152(2), 94-102

Trypanosoma evansi is an extracellular parasite found in the blood and tissues of mammals, mainly causing anaemia, immune depression and central nervous system disorders. Contrary to other African ... [more ▼]

Trypanosoma evansi is an extracellular parasite found in the blood and tissues of mammals, mainly causing anaemia, immune depression and central nervous system disorders. Contrary to other African trypanosomes, T. evansi is mechanically transmitted and thus presents a worldwide distribution. This review aims at summarizing clinical and pathological data about T. evansi infections in its various hosts. It presents the actual knowledge on pathogenesis and the recent development of which open new ways for infection control. [less ▲]

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See detailEpidémiologie de l'infection par Trypanosoma evansi
Antoine-Moussiaux, Nicolas ULg; Desmecht, Daniel ULg

in Annales de Médecine Vétérinaire (2008), 152(3), 191-201

Trypanosoma evansi is an extracellular parasite, found in blood and tissues, mainly causing anaemia, immune depression and central nervous system disorders. Contrary to other African trypanosomes, T ... [more ▼]

Trypanosoma evansi is an extracellular parasite, found in blood and tissues, mainly causing anaemia, immune depression and central nervous system disorders. Contrary to other African trypanosomes, T. evansi is adapted to mechanical transmission and thus, presents a worldwide distribution. This review summarizes the epidemiological data about T. evansi from its origins to the latest developments, as its addition in 2008 to the World Organization for Animal Health (OIE) listed diseases and other diseases of importance to International Trade. This article puts emphasis on the need for a coordinated epidemiological control strategy and research for improving diagnostic and control tools. [less ▲]

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See detailCavernous hemangiosarcoma in a free-living red deer (Cervus elaphus)
Grégoire, Fabien ULg; Mousset, Bénédicte ULg; Hanrez, David ULg et al

in Veterinary Record : Journal of the British Veterinary Association (2008), 162

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See detailLes facteurs de virulence d’Actinobacillus pleuropneumoniae, l’agent étiologique de la pleuropneumonuie porcine
Vanden Bergh, Philippe ULg; Fett, Thomas ULg; Zecchinon, Laurent ULg et al

in Annales de Médecine Vétérinaire (2008), 152(2), 74-96

Porcine pleuropneumonia caused by Actinobacillus pleuropneumoniae is a frequent and highly infectious disease generating significant economic losses related to deficiency in zootechnical profits and ... [more ▼]

Porcine pleuropneumonia caused by Actinobacillus pleuropneumoniae is a frequent and highly infectious disease generating significant economic losses related to deficiency in zootechnical profits and intensive use of antibiotics. This synthesis aims to review the bacterium elements necessary to pathogenesis development. At first time, we describe activation, secretion and cytotoxic action of Apx toxins, recognized as A. pleuropneumoniae major virulence factors. Then, we develop the other ones which are the lipopolysaccharides, the polysaccharidic capsule, the fimbriae, iron and other nutrients capture systems, various proteases, installation of certain metabolic ways, flagella and the biofilm. [less ▲]

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See detailHighly effective SNP-based association mapping and management of recessive defects in livestock.
Charlier, Carole ULg; Coppieters, Wouter ULg; Rollin, Frédéric ULg et al

in Nature Genetics (2008), 40(4), 449-54

The widespread use of elite sires by means of artificial insemination in livestock breeding leads to the frequent emergence of recessive genetic defects, which cause significant economic and animal ... [more ▼]

The widespread use of elite sires by means of artificial insemination in livestock breeding leads to the frequent emergence of recessive genetic defects, which cause significant economic and animal welfare concerns. Here we show that the availability of genome-wide, high-density SNP panels, combined with the typical structure of livestock populations, markedly accelerates the positional identification of genes and mutations that cause inherited defects. We report the fine-scale mapping of five recessive disorders in cattle and the molecular basis for three of these: congenital muscular dystony (CMD) types 1 and 2 in Belgian Blue cattle and ichthyosis fetalis in Italian Chianina cattle. Identification of these causative mutations has an immediate translation into breeding practice, allowing marker assisted selection against the defects through avoidance of at-risk matings. [less ▲]

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See detailProbing of Actinobacillus pleuropneumoniae ApxIIIA toxin-dependent cytotoxicity towards mammalian peripheral blood mononucleated cells
Vanden Bergh, Philippe ULg; Zecchinon, Laurent ULg; Fett, Thomas ULg et al

in BMC Research Notes (2008)

BACKGROUND: Actinobacillus pleuropneumoniae, the causative bacterial agent of porcine pleuropneumonia, produces Apx toxins which belong to RTX toxin family and are recognized as the major virulence ... [more ▼]

BACKGROUND: Actinobacillus pleuropneumoniae, the causative bacterial agent of porcine pleuropneumonia, produces Apx toxins which belong to RTX toxin family and are recognized as the major virulence factors. So far, their target receptor(s) has not been identified and the disease cytopathogenesis remains poorly understood. Production of an active Apx toxin and characterization of its toxic activity constitute the premises necessary to the description of its interaction with a potential receptor. From this point of view, we produced an active recombinant ApxIIIA toxin in order to characterize its toxicity on peripheral blood mononucleated cells (PBMCs) isolated from several species. FINDINGS: Toxin preparation exercises a strong cytotoxic action on porcine PBMCs which is directly related to recombinant ApxIIIA since preincubation with polymyxin B does not modify the cytotoxicity rate while preincubation with a monospecific polyclonal antiserum directed against ApxIIIA does. The cell death process triggered by ApxIIIA is extremely fast, the maximum rate of toxicity being already reached after 20 minutes of incubation. Moreover, ApxIIIA cytotoxicity is species-specific because llama, human, dog, rat and mouse PBMCs are resistant. Interestingly, bovine and caprine PBMCs are slightly sensitive to ApxIIIA toxin too. Finally, ApxIIIA cytotoxicity is cell type-specific as porcine epithelial cells are resistant. CONCLUSION: We have produced an active recombinant ApxIIIA toxin and characterized its specific cytotoxicity on porcine PBMCs which will allow us to get new insights on porcine pleuropneumonia pathogenesis in the future. [less ▲]

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See detailEvidence for transplacental transmission of the current wild-type strain of bluetongue virus serotype-8 in cattle
Desmecht, Daniel ULg; Vanden Bergh, Raphaël ULg; Sartelet, Arnaud ULg et al

in Veterinary Record : Journal of the British Veterinary Association (2008), 163

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See detailMannheimia haemolytica leukotoxin-induced cytolysis of caprine (Capra hircus) leukocytes is mediated by the CD18 subunit of beta2-integrins
Fett, Thomas ULg; Zecchinon, Laurent ULg; Vanden Bergh, Philippe ULg et al

in Microbial Pathogenesis (2008), 45

Mannheimiosis is the major respiratory disease among some ruminants, whereas it is not pathogenic for other mammals, an observation that has been attributed to a specific interaction between Mannheimia ... [more ▼]

Mannheimiosis is the major respiratory disease among some ruminants, whereas it is not pathogenic for other mammals, an observation that has been attributed to a specific interaction between Mannheimia haemolytica leukotoxin (Lkt) and bovine or ovine CD18 subunit of lymphocyte function-associated antigen-1 (LFA-1) and Mac-1. We therefore hypothesized that Lkt utilizes CD18 as its receptor on caprine leukocytes as well. We have transiently transfected the b2-integrins-deficient K-562 cell line with cDNAs encoding caprine CD11a and caprine CD18 to determine the susceptibility of the transfectants to Lktinduced cytolysis. Flow cytometric analysis of the transfectants revealed surface expression of caprine LFA-1 and lysis by Lkt in a concentration-dependent manner whereas the parent cells were not. Moreover, K562 cells expressing caprine CD18 and human or bovine CD11a were also sensitive to Lkt whereas K-562 cells expressing caprine CD11a and human CD18 were not. Taken together, these results indicate that CD18 on caprine leukocytes serves as a receptor for Lkt. [less ▲]

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See detailRevue morphopathologique des myopathies équines
Cassart, Dominique ULg; Desmecht, Daniel ULg; Coignoul, Freddy ULg

in Annales de Médecine Vétérinaire (2008), 152(1), 01-16

Dans cette revue morphopathologique des myopathies du cheval, plus particulièrement de celles qui atteignent la musculature striée squelettique, l’accent est mis délibérément sur le fil conducteur ... [more ▼]

Dans cette revue morphopathologique des myopathies du cheval, plus particulièrement de celles qui atteignent la musculature striée squelettique, l’accent est mis délibérément sur le fil conducteur histopathologique et, plus particulièrement, sur les éléments morphologiques qui permettent de classer les lésions observées dans un groupe d’entités connues. Le mot myopathie est, dans cet article, pris au sens le plus large, c’est-à-dire au sens étymologique du terme, signifiant toute affection du système musculaire. Sur base des lésions histologiques, on distingue quatre groupes d’affections musculaires ou myopathies : (i) celles qui se caractérisent par une modification de la taille des fibres musculaires, (ii) celles qui se caractérisent par une modification de l’aspect des fibres musculaires, (iii) celles qui se caractérisent par un infiltrat cellulaire de l’interstitium et (iv) celles sans expression morphologique typique avec soit absence de lésions, soit présence concomitante de plusieurs types de lésions sans qu’une lésion domine le tableau. Pour chaque entité décrite dans ces différentes classes, les conditions d’apparition, un tableau clinique succinct, le mécanisme et l’étiologie lorsqu’ils sont connus ainsi que les lésions macroscopiques sont également exposés. [less ▲]

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See detailDendritic cells genetically engineered to express IL-10 induce long-lasting antigen-specific tolerance in experimental asthma.
Henry, E.; Desmet, Christophe ULg; Garze, V. et al

in Journal of Immunology (2008), 181(10), 7230-7242

Dendritic cells (DCs) are professional APCs that have a unique capacity to initiate primary immune responses, including tolerogenic responses. We have genetically engineered bone marrow-derived DCs to ... [more ▼]

Dendritic cells (DCs) are professional APCs that have a unique capacity to initiate primary immune responses, including tolerogenic responses. We have genetically engineered bone marrow-derived DCs to express the immunosuppressive cytokine IL-10 and tested the ability of these cells to control experimental asthma. A single intratracheal injection of OVA-pulsed IL-10-transduced DCs (OVA-IL-10-DCs) to naive mice before OVA sensitization and challenge prevented all of the cardinal features of airway allergy, namely, eosinophilic airway inflammation, airway hyperreactivity, and production of mucus, Ag-specific Igs, and IL-4. OVA-IL-10-DCs also reversed established experimental asthma and had long-lasting and Ag-specific effects. We furthermore showed, by using IL-10-deficient mice, that host IL-10 is required for mediating the immunomodulatory effects of OVA-IL-10-DCs and demonstrated a significant increase in the percentage of OVA-specific CD4(+)CD25(+)Foxp3(+)IL-10(+) regulatory T cells in the mediastinal lymph nodes of OVA-IL-10-DC-injected mice. Finally, adoptive transfer of CD4(+) mediastinal lymph node T cells from mice injected with OVA-IL-10-DCs protected OVA-sensitized recipients from airway eosinophilia upon OVA provocation. Our study describes a promising strategy to induce long-lasting Ag-specific tolerance in airway allergy. [less ▲]

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See detailFlow Cytometric Probing of Mitochondrial Function in Equine Peripheral Blood Mononuclear Cells
Cassart, Dominique ULg; Fett, Thomas ULg; Sarlet, Michaël ULg et al

in BMC Veterinary Research (2007), 3

BACKGROUND: The morphopathological picture of a subset of equine myopathies is compatible with a primary mitochondrial disease, but functional confirmation in vivo is still pending. The cationic dye JC-1 ... [more ▼]

BACKGROUND: The morphopathological picture of a subset of equine myopathies is compatible with a primary mitochondrial disease, but functional confirmation in vivo is still pending. The cationic dye JC-1 exhibits potential-dependent accumulation in mitochondria that is detectable by a fluorescence shift from green to orange. As a consequence, mitochondrial membrane potential can be optically measured by the orange/green fluorescence intensity ratio. A flow cytometric standardized analytic procedure of the mitochondrial function of equine peripheral blood mononuclear cells is proposed along with a critical appraisal of the crucial questions of technical aspects, reproducibility, effect of time elapsed between blood sampling and laboratory processing and reference values. RESULTS: The JC-1-associated fluorescence orange and green values and their ratio were proved to be stable over time, independent of age and sex and hypersensitive to intoxication with a mitochondrial potential dissipator. Unless time elapsed between blood sampling and laboratory processing does not exceed 5 hours, the values retrieved remain stable. Reference values for clinically normal horses are given. CONCLUSION: Whenever a quantitative measurement of mitochondrial function in a horse is desired, blood samples should be taken in sodium citrate tubes and kept at room temperature for a maximum of 5 hours before the laboratory procedure detailed here is started. The hope is that this new test may help in confirming, studying and preventing equine myopathies that are currently imputed to mitochondrial dysfunction. [less ▲]

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See detailTrypanosoma evansi in five inbred mouse strains: anaemia
Antoine-Moussiaux, Nicolas ULg; Desmecht, Daniel ULg

Conference (2007, May 20)

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See detailDifferential anti-influenza activity among allelic variants at the Sus scrofa Mx1 locus
Palm, Mélanie; Leroy, Michael; Thomas, Anne et al

in Journal of Interferon & Cytokine Research (2007), 27(2), 147-155

A promising way to oppose infectious challenges would be to improve the resistance of the target species through genetic selection. Theoretically, a candidate gene is available against influenza viruses ... [more ▼]

A promising way to oppose infectious challenges would be to improve the resistance of the target species through genetic selection. Theoretically, a candidate gene is available against influenza viruses since a resistance trait was fortuitously discovered in the A2G mouse strain. This trait was demonstrated to be correlated with the expression of a specific isoform of the type I interferon (IFN)-dependent protein MX, an isoform coded by a specific allele at the mouse Mx1 locus. Two allelic polymorphisms were described recently in the Sus scrofa homologous gene. In this study, the frequencies and distribution of both alleles were evaluated among European domestic pig and wild boar populations by PCR-RFLP, and the anti-influenza activity conferred by both MX1 isoforms was evaluated in vitro using transfection of Vero cells followed by flow cytometric determination of the fraction of influenza virus-infected cells among MX-producing and MX-nonproducing cell populations. A significant difference in the anti-influenza activity brought by the two MX1 isoforms was demonstrated, which suggests that a significant improvement of innate resistance of pigs by genetic selection might be feasible provided the differences found here in vitro are epidemiologically relevant in vivo. [less ▲]

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See detailMorphological alterations in oxidative muscles and mitochondrial structure associated with equine atypical myopathy
Cassart, Dominique ULg; Baise, Etienne ULg; Cherel, Yann et al

in Equine Veterinary Journal (2007), 39(1), 26-32

REASONS FOR PERFORMING STUDY: There is a lack of well documented studies about muscular lesions in equine atypical myopathy (EAM). <br /> <br />OBJECTIVES: To characterise morphopathological changes of ... [more ▼]

REASONS FOR PERFORMING STUDY: There is a lack of well documented studies about muscular lesions in equine atypical myopathy (EAM). <br /> <br />OBJECTIVES: To characterise morphopathological changes of striated muscles and myocardium, to progress understanding of this disease. <br /> <br />METHODS: Thirty-two horses age 0.5-7 years kept on pasture were referred for a sudden ataxia/myoglobinuria syndrome. Clinical examination (stiffness, muscle pain, muscle fasciculations, abnormal gait, recumbency, myoglobinuria, tachycardia, sweating) and plasma CPK, LDH and AST levels were consistent with extensive myonecrosis and, together with anamnestic data, with so-called 'equine atypical myopathy' (EAM), a disease of unknown aetiology reported since 1939. Macroscopic and microscopic (histology, histoenzymology, ultrastructure) lesions were evaluated. <br /> <br />RESULTS: Necropsic examination revealed large areas of muscle necrosis, the extent and severity of which varied between cases and muscles, but which were clearly more constant and severe in respiratory and postural muscles and in the myocardium. Histology highlighted a multifocal and monophasic process compatible with Zenker degeneration/necrosis that mostly and segmentally affected type 1 fibres. Histochemical evaluation revealed a weak and disorganised pattern of NADH tetrazolium reductase staining, the absence of calcium salts precipitates and a dramatic accumulation of lipid droplets. Ultrastructural examination often revealed fibres of which the sole modifications were altered mitochondria and sarcoplasmic lipidosis. <br /> <br />CONCLUSIONS: Taken together, the data suggest that a primary alteration of mitochondria should be considered, although secondary mitochondrial abnormalities have yet to be ruled out. <br /> <br />POTENTIAL RELEVANCE: The morphological features gathered here reveal that EAM shares most of the characteristics of toxic myopathies. [less ▲]

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See detailThe wild boar (Sus scrofa) Lymphocyte function-associated antigen-1 (CD11a/CD18) receptor : cDNA sequencing, structure analysis and comparison with homologues
Vanden Bergh, Philippe ULg; Zecchinon, Laurent ULg; Fett, Thomas ULg et al

in BMC Veterinary Research (2007), 3

BACKGROUND: The most predominant beta2-integrin lymphocyte function-associated antigen-1 (LFA-1, CD11a/CD18, alphaLbeta2), expressed on all leukocytes, is essential for many adhesive functions of the ... [more ▼]

BACKGROUND: The most predominant beta2-integrin lymphocyte function-associated antigen-1 (LFA-1, CD11a/CD18, alphaLbeta2), expressed on all leukocytes, is essential for many adhesive functions of the immune system. Interestingly, RTX toxin-producing bacteria specifically target this leukocyte beta2-integrin which exacerbates lesions and disease development. RESULTS: This study reports the sequencing of the wild boar beta2-integrin CD11a and CD18 cDNAs. Predicted CD11a and CD18 subunits share all the main structural characteristics of their mammalian homologues, with a larger interspecies conservation for the CD18 than the CD11a. Besides these strong overall similarities, wild boar and domestic pig LFA-1 differ by 2 (CD18) and 1 or 3 (CD11a) substitutions, of which one is located in the crucial I-domain (CD11a, E168D). CONCLUSION: As most wild boars are seropositive to the RTX toxin-producing bacterium Actinobacillus pleuropneumoniae and because they have sustained continuous natural selection, future studies addressing the functional impact of these polymorphisms could bring interesting new information on the physiopathology of Actinobacillus pleuropneumoniae-associated pneumonia in domestic pigs. [less ▲]

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See detailThe Mus musculus Mx1 gene confers strong protection against highly pathogenic influenzavirus A H5N1
Garigliany, Mutien-Marie ULg; Lambrecht, Bénédicte; Leroy, Michaël et al

Poster (2007)

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