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Marek’s Disease Virus Replication in Chicken Skin Reconstructed In Vitro: Evidence for Viral Particles in Corneocytes
No full textInternational audienceMarek’s disease (MD) is a lethal lymphoma of chickens, which is caused by MD virus (MDV), an alphaherpesvirus. MDV infects epithelial cells of the skin appendages, notably feather follicles, replicates in these cells and is shed into the environment exclusively from these tissues. Here, we tested whether chicken skin equivalents (SEs) can be used to model MDV infection. Primary chicken keratinocytes were seeded on a suspension of fibroblasts in collagen and induced to terminally differentiate at the air-liquid interface. A recombinant MDV expressing the Katushka fluorescent protein (MDV-KAT) was introduced into SEs by seeding of primary keratinocytes together with MDV-KAT-infected keratinocytes of the K8 cell line. KAT-mediated fluorescence increased during the culture of infected SEs, indicating virus infection and replication, while the expression of keratinocyte differentiation markers was not significantly altered by MDV infection. MDV did not spread to the dermal compartment of SEs, but localized to the upper layers of the epidermis. Viral particles were readily observed by electron microscopy in living keratinocytes and for the first time in cornified keratinocytes of the outermost layer of infected SEs, evidence for excretion of viral elements into environment. Finally, we demonstrated that two fluorescent vaccine strains of MDV, Rispens and herpesvirus of turkey, can infect and replicate in SEs. Taken together, this study establishes chicken SEs as an in vitro model for MDV infection
Antimicrobial properties of selected microalgae exopolysaccharide-enriched extracts: influence of antimicrobial assays and targeted microorganisms
No full textInternational audienceExopolysaccharide (EPS)-enriched extracts derived from microalgae exhibit a wide range of bioactive properties, including antibacterial and antifungal properties. However, these properties vary depending on the microalgae species, the antimicrobial assay used, and selected targeted microorganisms. This study offers to investigate the antimicrobial properties of exopolysaccharide-enriched extracts obtained from five microalgae species scarcely studied in this context. The targeted microorganisms selected for this study included Gram-positive (Bacillus subtilis) and Gram-negative bacteria (Pseudomonas aeruginosa), fungi (Cladosporium cladosporioides), and microalgae (Chlorella vulgaris). Well-diffusion assay, broth microdilution assay, and growth measurements using absorbance were used to compare the methods and fully estimate the antimicrobial properties. Using absorbance measurements, growth rate inhibitions of at least 80% were observed on all targeted species for at least one microalgal EPS-enriched extract. At a concentration of 500 mgGlcEq • L -1 , most active extracts of B. subtilis were obtained from Chlamydomonas reinhardtii (87.1% of growth inhibition), Nostoc commune (53.7%), and Eustigmatos polyphem (46.4%). EPS-enriched extracts from C. reinhardtii (86.2%), N. commune (59.9%), and Porphyridium cruentum (31.1%) were found to be the most effective against P. aeruginosa. Antifungal activities were the highest for EPS extracts from Microchloropsis gaditana (86.0%), C. reinhardtii (16.6%), and E. polyphem (17.8%). The results indicated microalgae growth inhibition by EPS-enriched extracts from N. commune (99.3%), C. reinhardtii (84.8%), and M. gaditana (84.1%). To our knowledge, this study is the first to explore the algicidal properties of EPS-enriched extracts derived from microalgae, identifying promising candidates for future investigations into their potential applications
Contralateral R1 response in blink reflex in patients with amyotrophic lateral sclerosis
No full textInternational audienceObjective: This study aimed to compare the frequency of blink reflex's contralateral R1 responses (R1') between patients with amyotrophic lateral sclerosis (ALS), non-ALS motor deficit patients, and healthy volunteers.Methods: A total of 120 participants were prospectively recruited: 40 with ALS, 40 with a non-ALS motor deficit, and 40 healthy volunteers. Blink reflexes were recorded from orbicularis oculi muscles following supraorbital nerve stimulation.Results: R1' was more frequent in the ALS group (42.5 %) compared to healthy volunteers (12.5 %, p = 0.00588), and compared to non-ALS patients (7.5 %, p = 0.000789). Bilateral R1' was observed only in ALS patients (22.5 %). No clinically significant difference was found in the latencies or amplitudes of the R1, R2, or R1' responses among groups. R1' was more frequent in ALS patients with pseudobulbar affect (71.4 %) compared to those without (36.4 %).Conclusions: The higher frequency of R1' in ALS highlights its potential role in distinguishing ALS from other motor disorders. Its sensitivity was low, but bilateral R1' was specific to ALS. The higher frequency of R1' among ALS patients with pseudobulbar affect potentially reflects corticobulbar neuron degeneration.Significance: The R1', especially when bilateral, could serve as an additional diagnostic biomarker for ALS, although its clinical relevance should be considered within the broader diagnostic context
Examen post mortem de l’encéphale chez les bovins : identifier les lésions clés
No full textInternational audienceBovine neurological diseases, which affect up to 6% of animals, have a variety of causes (infectious, deficiency-related, genetic, metabolic, toxic, etc.). The diagnosis is complex because signs are often not very specific when the animal is alive. A rigorous ante-mortem neurological examination and a macroscopic post-mortem examination are essential to refine the hypotheses and take the appropriate samples for further analysis (histology, bacteriology, PCR). The encephalon, comprising the brain, cerebellum and brainstem, may have specific lesions depending on the disease: hydrocephalus, hydranencephaly, cerebellar hypoplasia, haemorrhages, meningitis, encephalitis, abscesses, polioencephalomalacia (necrosis of the cerebral cortex or vitamin B1 deficiency), or tumours. The autopsy requires strict biosanitary precautions and a precise protocol for extracting and examining the brain. Histological analysis, examination of the CSF and bacteriology can help confirm the diagnosis. However, intoxication and metabolic disorders often remain diagnoses of exclusion, and have to be compared with the epidemiological and clinical context.Les maladies neurologiques bovines, touchant jusqu’à 6 % des animaux, sont de causes variées (infectieuses, carentielles, génétiques, métaboliques, toxiques, etc.). Leur diagnostic est complexe en raison de signes souvent peu spécifiques du vivant de l’animal. Un examen neurologique rigoureux ante mortem et un examen macroscopique post mortem sont essentiels pour affiner les hypothèses et réaliser les prélèvements adéquats pour des analyses complémentaires (histologie, bactériologie, PCR). L’encéphale, composé du cerveau, du cervelet et du tronc cérébral, peut présenter des lésions spécifiques selon les affections : hydrocéphalie, hydranencéphalie, hypoplasie cérébelleuse, hémorragies, méningites, encéphalites, abcès, polioencéphalomalacie (nécrose du cortex cérébral ou carence en vitamine B1) ou tumeurs. L’autopsie exige des précautions biosanitaires strictes et un protocole précis pour extraire et examiner l’encéphale. L’analyse histologique, l’examen du LCS et la bactériologie peuvent aider à confirmer le diagnostic. L’intoxication et les troubles métaboliques restent toutefois souvent des diagnostics d’exclusion, à confronter avec le contexte épidémio-clinique
Etude de l'effet de la gabapentine sur l'efficacité d'un protocole de désensibilisation contre-conditionnement dans une population de chats phobiques des soins
No full textCette étude évalue l'effet de la gabapentine sur la vitesse d'apprentissage d'un protocole de désensibilisation-contre-conditionnement (DS-CC) chez les chats phobiques des soins. L’objectif était de démontrer que la gabapentine, au-delà de ses effets anxiolytiques (Kruszka et al., 2021 ; Pankratz et al., 2018 ; Salamon et al., 2023 ; Van Haaften et al., 2017), ne se limite pas à une molécule facilitant la contention, mais constitue un traitement facilitant la thérapie comportementale. Quarante-deux chats sensibilisés ont participé à un protocole de désensibilisation contre conditionnement. À l'aide d'un essai croisé en double aveugle, les chats ont suivi 10 séances d'entraînement réparties sur 2 semaines : les 5 premières sous 100mg de gabapentine et les 5 dernières sous placebo, ou inversement. Le protocole comprenait huit étapes visant à désensibiliser les chats à une coupe des griffes, en association avec un renforcement positif. L’évaluation des progrès se basait sur le nombre d’étapes franchies à chaque séance. Les résultats montrent que les chats progressaient significativement plus vite lorsqu’ils recevaient la gabapentine, comparé aux séances sous placebo (test des rangs signés de Wilcoxon, p < 0,0001). L'effet était important (size effect = 0,87), et indépendant de l’ordre d’administration du produit. Ainsi, la gabapentine apparait comme un véritable soutien en favorisant l’apprentissage des chats dans les protocoles DS-CC dédiés aux phobies des soins. Des études supplémentaires sont nécessaires pour évaluer son utilisation dans d’autres contextes de rééducation comportementale. Toutefois, ces résultats suggèrent que la gabapentine ne doit pas être perçue comme un moyen de contention ponctuel, mais comme un soutien thérapeutique à instaurer de manière précoce permettant de limiter les phobies des soins chez le chat et d’améliorer leur prise en charge en clinique vétérinaire
Repositioning of moxidectin: a promising approach in cutaneous leishmaniasis therapy
No full textInternational audienceCutaneous leishmaniasis presents a significant challenge to public health due to its diverse clinical manifestations, resistance development, and treatment-related adverse effects. Here, we examined the efficacy of ivermectin, moxidectin (MOX), afoxolaner, and permethrin against all stages of Leishmania tropica and THP-1 cells. We also assessed the potential for resistance acquisition after 15 rounds of artificial selection. To elucidate the mode of action of MOX, we employed RNA sequencing, molecular dynamics simulation, and chloride flux assays. Additionally, we evaluated the therapeutic index of MOX using the Galleria mellonella infection model. MOX demonstrated the highest selectivity index against leishmaniasis (promastigotes: 0.58 μM; amastigotes: 0.96 μM; host cells: 60.29 μM). Moreover, MOX exhibited the lowest resistance acquisition in both promastigotes and intracellular amastigotes after 15 rounds of artificial selection, with resistance ratios of 17.23 and 4.59, respectively. Post-exposure to MOX, differential gene expression profiles showed both stage-specific and stage-unspecific enrichment of gene families involved in crucial biological processes. Moreover, molecular dynamics simulations revealed a potential neutralizing effect of MOX on the chloride channel of L. tropica. Specifically, MOX binds to the selectivity filter, potentially disrupting the osmotic equilibrium and thereby killing the parasite. The in vivo introduction of MOX significantly inhibited the growth of L. tropica in G. mellonella larvae, resulting in decreased rates of mortality and melanization. These findings indicate that MOX is a promising candidate for the treatment of L. tropica infections, warranting further investigation and potential consideration for clinical use
Assessing placental transfer and in utero reproductive effects in rats of a short-chained paraffin with in vitro endocrine disrupting properties
No full textInternational audienceChlorinated paraffins (CPs) are industrial chemicals detected widely in the environment and human tissues, raising concerns due to their persistence, bioaccumulation, and potential health risks. CPs with lower chlorination or shorter carbon chain lengths can cross the placenta and have been detected in breast milk, indicating fetal and early postnatal exposure. Both in vitro and in vivo studies suggest that CPs exhibit endocrine-disrupting properties, particularly affecting reproductive development. This study investigates the developmental effects and placental transfer of 1,2,9,10-tetrachlorodecane (T 4 C 10 ), a short-chained CP congener, by exposing pregnant rats from gestation days 7 to 21. T 4 C 10 concentrations were measured in fetal and maternal blood, fetal steroid hormone levels were measured, and targeted gene expression was analyzed in the fetal genital tubercle. Despite prior in vitro evidence of endocrine-disrupting activity, in vivo exposure to T 4 C 10 did not significantly affect reproductive parameters, including the anogenital distance (AGD), fetal steroid hormone profiles, or expression of androgen-and estrogen-regulated genes in the developing genital tubercle. The low systemic T 4 C 10 levels in maternal and fetal blood suggest rapid metabolism or sequestration in adipose tissue, supported by increased liver weight in the exposed dams. These findings suggest that while T 4 C 10 can cross the placenta, its bioavailability in vivo may be insufficient to elicit measurable endocrine-disrupting effects on reproductive development. This study underscores the importance of accounting for toxicokinetics when extrapolating in vitro findings to in vivo endpoints.</div
La stachybotryotoxicose : une intoxication équine d'actualité et peu connue
No full textInternational audienceStachybotryotoxicosis is a mycotoxicosis caused by Stachybotrys chartarum when it develops on humid dry forage. All animal species can be affected by this intoxication, although horses appear to be the most senstitive species. The mycotoxins produced are powerful inhibitors of protein syntheses, with more marked effect on cells with rapid turnover. Clinical signe vary greatly depending on the animal and the quantity and nature of the toxins present. Mucocutaneous lesions are common in equids, sometimes accompanied by systemic damage. The clinical picture is polymorphous and this condition should be considered in cases of complex differential diagnosis.La stachybotryotoxicose est une mycotoxicose due à Stachybotrys chartarum lors de son développement sur les fourrages secs réhumidifiés. Si toutes les espèces animales peuvent être concernées par cette intoxication, les chevaux semblent être l'espèce la plus sensible. Les mycotoxines produites sont de puissants inhibiteurs de la synthèse protéique dont les effets sont plus marqués sur les cellules à renouvellement rapide. Les signes cliniques peuvent être très variables selon les animaux, la quantité et la anture des toxines présentes. Des lésions cutanéo-muqueuses sont fréquentes chez les équidés, parfois accompagnées d'une atteinte systémique. Le tableau clinique est polymorphe et cette affection doit être considérée en cas de diagnostic différentiel complexe
Intoxication chez les équidés : toxiques fréquents et émergents en France métropolitaine
No full textInternational audienceThere are still relatively few calls concerning equidae to French veterinary poison control centres. However, horses are regularly exposed to toxic substances that could endanger the animals if not removed from the environment. Plants are the main category of toxic substances reported to veterinary poison contro; centres.The most common are generally well identified by equine professionals, who seek advice on the risks and management. The toxicity of other poisons is still poorly understood and cases should be reported in order to gain a better understanding and knowledge of the effects of these substances. Also, horses are increasingly being found in contact with certain plants that were previously rare, so professionals need to be made aware of the risks associated with these plants.Les appels concernant les équidés auprès des centres antipoison vétérinaires français restent relativement peu nombreux. Cependant, les chevaux sont régulièrement exposés à des toxiques susceptibles de les mettre en danger s'ils ne sont pas retirés de leur environnement. Les plantes sont la principale catégorie de toxiques recensée par les centres antipoison vétérinaires. Les plus fréquentes sont généralement bien identifiées par les professionnels équins qui sollicitent des conseils sur les risques et la prise en charge. Pour d'autres, la toxicité est encore mal comprise et nécessite de faire remonter les cas pour préciser les connaissances. Enfin, certaines plantes jusqu'alors rares se retrouvent de plus en plus fréquemment au contact des chevaux, appelant à sensibiliser les professionnels aux risques qui leur sont liés
Associations between foot lesions and carcass traits in young bulls
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