References of "Desmecht, Daniel"
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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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See detailThe expression of Clostridium perfringens consensus beta2 toxin is associated with bovine enterotoxaemia syndrome
Lebrun, Maud; Filée, Patrice ULg; Mousset, Bénédicte ULg et al

in Veterinary Microbiology (2007), 120(1-2), 151-157

Clostridium perfringens has been implicated in a broad array of enteric infections including the fatal haemorrhagic enteritis/enterotoxaemia syndrome in cattle. The beta2 toxin (CPB2), encoded by cpb2, is ... [more ▼]

Clostridium perfringens has been implicated in a broad array of enteric infections including the fatal haemorrhagic enteritis/enterotoxaemia syndrome in cattle. The beta2 toxin (CPB2), encoded by cpb2, is suspected to be implicated in this syndrome. However, among C. perfringens isolates from cattle suspected of clostridial disease, an atypical allele was recently found to predominate at the cpb2 locus and atypical corresponding CPB2 proteins were shown to be poorly expressed, thus arguing against a biologically significant role of the beta2 toxin in clostridial diseases in cattle. This study compared genotype and phenotype of the beta2 toxin between C. perfringens isolates from a group of healthy calves (n = 14, 87 isolates) and from a group of enterotoxaemic calves (n = 8,41 isolates). PCR results revealed the exclusive presence of the typical "consensus" cpb2 in the enterotoxaernic group. Western blot analysis demonstrated that the typical variant of CPB2 was often expressed in isolates from enterotoxaemic calves (43.9%) and infrequently in isolates from healthy cattle (6.9%). These data suggest that the typical variant of the CPB2 toxin may play a role in the pathogenesis of cattle enterotoxaemia. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailLa tumeur faciale transmissible du Diable de Tasmanie
Vanherberghen, Morgane ULg; Desmecht, Daniel ULg

in Annales de Médecine Vétérinaire (2007), 151

The Tasmanian Devil is the largest carnivorous marsupial of Australia. Since 1996, this species faces an emerging transmissible and fatal disease that is characterized by eruption of tumors on the face ... [more ▼]

The Tasmanian Devil is the largest carnivorous marsupial of Australia. Since 1996, this species faces an emerging transmissible and fatal disease that is characterized by eruption of tumors on the face and the neck. Having carried 75.000 animals off in only 8 years, the Tasmanian Devil’s transmissible tumor dramatically threatens the survival of the species, which would have disastrous ecological consequences because of its key role as a predator and as a scavenger. The following text gathers the information available on the features of the disease and brings to the light its astonishing etiology and mode of transmission [less ▲]

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See detailSendai virus, the mouse parainfluenza type 1: A longstanding pathogen that remains up-to-date
Faisca, Pedro; Desmecht, Daniel ULg

in Research in Veterinary Science (2007), 82(1), 115-125

Biologically speaking, Sendai virus (SeV), the murine parainfluenza virus type 1, is perceived as a common respiratory pathogen that is endemic in many rodent colonies throughout the world. Currently it ... [more ▼]

Biologically speaking, Sendai virus (SeV), the murine parainfluenza virus type 1, is perceived as a common respiratory pathogen that is endemic in many rodent colonies throughout the world. Currently it is believed that SeV is the leading cause of pneumonia in mice and together with the mouse hepatitis viruses, is the most prevalent and important of the naturally occurring infections of mice. The scientific community also considers SeV as the archetype organism of the Paramyxoviridae family because most of the basic biochemical, molecular and biologic properties of the whole family were derived from its own characteristics. Recently, scientific interest for this old pathogen has re-emerged, this time because of its potential value as a vector for gene transfer. This review aimed at drawing an exhaustive picture of this multifaceted pathogen. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailContribution of MX dynamin, oligoadenylate synthetase, and protein kinase R to anti-paramyxovirus activity of type-1 interferons in vitro
Leroy, M.; Baise, Etienne ULg; Pire, G. et al

in American Journal of Veterinary Research (2007), 68

OBJECTIVE: To determine the contribution of MX dynamin, oligoadenylate synthetase (OAS), and double-stranded RNA-dependent protein kinase R (PKR) to the antiviral effects of type 1 interferons (IFNs ... [more ▼]

OBJECTIVE: To determine the contribution of MX dynamin, oligoadenylate synthetase (OAS), and double-stranded RNA-dependent protein kinase R (PKR) to the antiviral effects of type 1 interferons (IFNs) against bovine parainfluenza-3 virus (PI-3V) infection of Vero cells. SAMPLE POPULATION: Vero cell cultures. PROCEDURES: PI-3V yield was first compared between control and transfected type 1 IFNs-incompetent Vero cells expressing recombinant OAS or MX proteins. Afterwards, phosphorylation of eukaryotic initiation factor 2 alpha (eIF2alpha) was used to scale the degree of PKR activation upon infection of Vero cells by PI-3V. RESULTS: Overexpression of OAS did not result in significantly decreased viral replication. Phosphorylated eIF2alpha forms, the hallmark of PKR activation, were not increased in IFNalpha-primed infected Vero cells. Although human MXA contributed to partial blockade of replication of bovine PI-3V, the antiviral effect was not as strong as that of IFNalpha. CONCLUSIONS AND CLINICAL RELEVANCE: The powerful anti-Paramyxovirus activity of type 1 IFNs is mediated by noncanonic pathways. [less ▲]

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See detailExperimentally induced epizootic rabbit enteropathy: Clinical, histopathological, ultrastructural, bacteriological and haematological findings
Dewrée, Roxane; Meulemans, L.; Lassence, Cédric ULg et al

in World Rabbit Science (2007), 15(2, APR-JUN), 91-102

Epizootic rabbit enteropathy is an emerging disease that has appeared in French intensive enclosed rabbit farms since the beginning of 1997. Common clinical signs are mild watery diarrhoea with ... [more ▼]

Epizootic rabbit enteropathy is an emerging disease that has appeared in French intensive enclosed rabbit farms since the beginning of 1997. Common clinical signs are mild watery diarrhoea with considerable distension of the abdomen. At necropsy, a significant dilation of the stomach and small intestine without gross evidence of acute or chronic enteric lesions (inflammation or congestion) was observed. The purpose of this study was to describe the anatomopathologic changes concerning the small intestine and those concerning the blood profile, in experimentally infected rabbits. In a first part of the experiment, thirty animals were inoculated with a reference inoculum and five were kept as controls for clinical signs examination and histopathological study. In a second part, 17 out of the inoculated rabbits and the 5 controls animals were randomly assigned to blood testing. Microscopic lesions were studied in sections from the different parts of the small intestine (duodenum, jejunum and ileum) by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The histological findings revealed only limited inflammation in inoculated animals. Major villous changes were atrophy, fusion, destruction and loss of epithelial cells. In inoculated rabbits, the congestion and dilation of blood vessels of jejunal lamina propria were significantly higher than in control animals (P<0.005). There was significantly more (P<0.05) apoptosis of cells of the jejunal epithelium in inoculated rabbits than in control animals. Infiltration of polymorphonuclear neutrophiles was observed into the jejunal or ileal tunica muscularis. SEM performed on the intestinal tract of 15 inoculated rabbits revealed blankets and globular particles of mucus associated with numerous bacteria on jejunum and ileum villi. This was; not observed in the intestinal tract of control rabbits. Bacteria were found adhering to the epithelial surface and inside intestinal epithelial cells in a few animals by TEM and by light microscopy after Warthin-Starry staining. None of the bacteria isolated from the intestinal mixed contents and cultivated on usual media, are commonly known as rabbit's pathogens. Regarding the haernatological profile, neutrophil counts significantly increased (P<0.05) and lymphocyte counts significantly decreased (P<0.01), in inoculated rabbits compared to those of the control group. [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, C. J.; Garzé, V. et al

Poster (2007)

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See detailEvaluation de l’efficacité du Caprofène lors de bronchoneumonie expérimentale bovine à Mannheimia haemolytica
Wallemacq, Hugues; Boutet, Philippe; Zecchinon, L. et al

in Revue de Médecine Vétérinaire (2007), 158(8-9), 418-424

M. haemolytica serotype A1 (formerly known as Pasteurella) is the most important and commonly isolated bacterial pathogen from fatal cases of bovine fibrinous pleuroneumonia. M. haemolytica and its two ... [more ▼]

M. haemolytica serotype A1 (formerly known as Pasteurella) is the most important and commonly isolated bacterial pathogen from fatal cases of bovine fibrinous pleuroneumonia. M. haemolytica and its two principal toxins, the lipopolysaccharides (LPS) and the leukotoxin (LktA) induce the recruitment, the activation and the necrosis of neutrophils involved in the pathogenicity of bovine pneumonic mannheimiosis (BPM). The objective of this study was to determine whether systemic therapy with carprofène (Rimadyl®*), a non-steroidal anti-inflammatory drug, improves the disease development in an acute experimental model of BPM. The experimental pathology was induced by trans-tracheal inoculation of M. haemolytica and toxins at T0. One hour post-inoculation, six calves were treated intravenously with carprofen (1,4 mg/kg) while six placebo-treated calves received dose-matched volumes of sterile saline. The clinical and biochemical parameters were measured at one (T+1), three (T+3) and seven (T+7) hours after inoculation. Disease scores for carprofen treated calves were significantly lower than those for placebo-treated controls six hours (T+7) after treatment. These results were associated to a significantly oxygen saturation decrease at T+3 and a significantly blood lactate increase at T+7 in the control calves. Moreover, pulmonary lesions were significantly less extensive than those in the control group. Taken together, this finding suggest that pharmacological modulation by carprofen of pulmonary inflammation after appearance of acute BPM clinical signs leads to calves’ health enhancement and reduces the extent of gross pneumonic lesion. [less ▲]

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See detailCongenital muscular dystonia (CMD): a new congenital pathology in Belgian Blue calves
Vandeputte, Sébastien ULg; Brihoum, Mounir ULg; Hubin, Xavier et al

Conference (2006, October 15)

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See detailFlow cytometry for the follow-up of Trypanosoma evansi infection in a mouse model
Antoine-Moussiaux, Nicolas ULg; Leroy, ; Faisca, et al

Poster (2006, April)

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See detailGenomic structure, promoter analysis and expression of the porcine (Sus scrofa) TLR4 gene.
Thomas, Anne; Broers, Aurore ULg; Vandegaart, Hélène ULg et al

in Molecular Immunology (2006), 43(6), 653-659

Toll-like receptor 4 (TLR4) is essential for initiating the innate response to lipopolysaccharide (LPS) from Gram-negative bacteria by acting as a signal-transducing receptor. As the pig industry faces a ... [more ▼]

Toll-like receptor 4 (TLR4) is essential for initiating the innate response to lipopolysaccharide (LPS) from Gram-negative bacteria by acting as a signal-transducing receptor. As the pig industry faces a unique array of related pathogens, it is anticipated that the genotype of swine TLR4 could be of crucial importance in future strategies aimed at improving genetic resistance to infectious diseases. In order to help in investigating TLR4 as a candidate disease-resistance gene in pigs, we established its genomic structure and produced sufficient flanking intronic sequences to enable simple PCR amplification of the coding portions of the gene. Expression in different porcine tissues was studied and showed splicing variations in mRNA sequences. The cDNA sequence for poTLR4 contains an open reading frame of 2526bp that codes for 841 aa, 98 and 568bp in the 5'- and 3'-UTRs, respectively. Overall, the general organization of porcine, human, murine, and avian TLR4 genes is quite similar: three exons with the third one very long. A high level of conservation of the size and the sequence, especially for the two last exons and particularly in the sequence corresponding to the LRRs and TIR domain, is observed between species. The important antimicrobial properties of these proteins may account for a conservative selection pressure on these TLR4 coding sequences. Several putative binding sites described in the human and murine promoter of TLR4 genes have been identified in the 5'-flanking region of poTLR4. Conversely, this region lacks a TATA box, consensus initiator sequences, or GC-rich regions. The basic sequence data gathered will allow the establishment of an inventory of naturally occurring variation in porcine TLR4, so that alleles can be tested for disease association studies. [less ▲]

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See detailLes interférons de type 1 et leur fonction antivirale
Leroy, Michael; Desmecht, Daniel ULg

in Annales de Médecine Vétérinaire (2006), 150(2), 73-107

Type I interferons are part of the innate immune system involved in the first line defense against invasion, replication and spreading of pathogens such as viruses. Through specific membrane or ... [more ▼]

Type I interferons are part of the innate immune system involved in the first line defense against invasion, replication and spreading of pathogens such as viruses. Through specific membrane or intracellular receptors, virus entry induces the expression of type I interferons which stimulates the cells through an autocrine and paracrine manner. Interferons are polypeptides that stimulate cells through membrane receptors. They induce a cascade of events leading to the synthesis of many proteins some of which having specific antiviral properties. The most characterized are the MX proteins, the 2’5’ oligoadenylate synthetase/ ribonuclease L pathway and the double-stranded RNA-dependent protein kinase R system. Recently, the protein ISG20 has been involved in the specific antiviral function of type I interferons. The interferons act on multiple steps of the viral cycle including penetration, decapsidation, mRNA transcription, protein synthesis, genome replication, assembling and excretion of viral particles. Nowadays, due to their major efficiency, type I interferons are used in therapeutics against some viral infections and cancers. [less ▲]

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