65 research outputs found
Necrotizing meningoencephalitis associated with cortical hippocampal hamartia in a Pekingese dog
No full textA 4-year-old male Pekingese dog was referred to the clinic with a history of recurrent seizures and progressive abnormal gait and behavior, which did not respond to treatment. At necropsy, a large cortical defect in the right temporo-parietal cortex, malacia of subcortical white matter, right basal nuclei, and capsula interna, as well as abnormalities of the right hippocampus were observed. Histological examination of the brain revealed moderate to severe nonsuppurative meningoencephalitis in the left cerebral hemisphere and extensive infarction-like lesions with milder inflammation in the right hemisphere. In the right hippocampus, the pyramidal cells were arranged in a gyrus-like pattern and intermingled with gemistocytic and fibrillary astrocytes. The histopathological features of the inflammatory lesions were consistent with necrotizing meningoencephalitis and resembled those described in so-called Pug dog encephalitis. The hippocarnpal changes were interpreted as dysplasia (monolateral hippocarnpal cortical hamartia), unrelated to clinical signs and necrotizing inflammatory lesions
Relazione fra il colore delle carcasse ed alcuni parametri qualitativi della carne di vitelloni Chianini
No full textPer verificare l'esistenza di correlazioni fra alcune caratteristiche qualitative della carcassa ed i principali parametri di qualità della carne, è stato rilevato il colore dei muscoli rectus abdominis e longissimus dorsi di 50 carcasse di vitelloni Chianini allevati secondo le norme del disciplinare "Vitellone Bianco dell'Appennino Centrale" (IGP). Sono stati quindi prelevati campioni di carne che dopo 14 giorni di frollatura sono stati analizzati per la determinazione dei principali parametri di qualità. Le caratteristiche qualitative della carne sono in linea con quelle tipiche della razza; sono state evidenziate correlazioni interessanti fra i parametri colorimetrici rilevati sulla caracassa a livello del muscolo longissimus lumborum e quelli misurati sulla carne, lasciando intravedere la possibilità di stimare il colore della carne a partire da semplici misurazioni di carcassa
Specific diagnostic tools for protozoan infection of ruminants
No full textNeospora caninum, Toxoplasma gondii and Sarcocystis spp. are closely related
intracellular protozoan parasites causing neosporosis, toxoplasmosis and
sarcocystosis, respectively. Toxoplasma and Neospora are major causes of abortion in
livestock worldwide leading to substantial economic losses. Toxoplasma is a well-known
infectious parasite of sheep and a wide range of warm-blooded animals,
including humans. Neospora predominantly causes disease in cattle, although
infections in other warm-blooded animals have been found to cause disease.
Sarcocystis infect a wide range of intermediate and definitive mammalian hosts.
Although abortion is a major problem for livestock operations and animal welfare
worldwide, the identification of a specific cause is particularly difficult and achieved
in less than 50% of the cases, even in well-established diagnostic laboratories.
Neospora, Toxoplasma, and Sarcocystis spp. share many common morphological and
biological similarities making differentiation through immunological methods
between these protozoan parasites challenging. Aetiological diagnostics tests are
required to confirm the presence of association of disease with specific parasites, and
to determine the cause of abortion to adopt the most relevant disease control strategy.
As such, it is necessary to have access to specific diagnostic tools to confirm or rule
out the presence of Toxoplasma gondii, Neospora caninum, and Sarcocystis spp. as
the cause of abortion in mammalian species.
The primary aim of this PhD was to develop a genus-specific PCR assay for the
detection of N. caninum, T. gondii and Sarcocystis spp. using fixed and fresh tissue
material. Suitable target regions for the production of genus-specific PCR primers
were identified using the 18S rRNA gene and ITS1 regions. Primers were tested for
sensitivity and specificity using DNA from various protozoan parasites. For the 18S
rRNA gene, general PCR primers were developed to amplify DNA from Neospora,
Toxoplasma and Sarcocystis spp. 18S group-specific primers were developed to enable
detection of T. gondii and N. caninum from Sarcocystis spp. Several 18S Sarcocystis
specific group primers were developed to enable differentiation of a variety of
Sarcocystis spp. Species-specific primers were developed using the ITS1 region to
enable diagnosis of Neospora from Toxoplasma. PCR assays were standardized, and
primers were validated using DNA extracted from fixed and fresh tissues to enable the
diagnosis of different protozoan species.
The second aim was to develop genus-specific antibodies (polyclonal and monoclonal)
raised against recombinant proteins of N. caninum, T. gondii and Sarcocystis spp. to
enable specific diagnosis. For this aim, suitable target genes for the production of
recombinant proteins for Neospora, Toxoplasma and Sarcocystis spp. were identified.
Recombinant proteins were expressed using E. coli and analysed for cross-reactivity.
Three recombinant proteins for Neospora, three for Toxoplasma and one for
Sarcocystis were successfully expressed. Of those, two recombinant proteins for
Neospora (rNcSRS2 and rNcSAG1) and one recombinant protein for Toxoplasma
(rTgSRS2) were used for subsequent antibody production.
For the development of polyclonal antisera, rabbit pre-immune sera were tested to
choose the best candidate for immunisation using the recombinant proteins. Polyclonal
sera were tested using immunohistochemistry for functionality and specificity. The
polyclonal antibodies were validated using a range of ruminant clinical cases suspected
of protozoal infections. Based on the recombinant protein expression the best
candidates were taken forward for the development of a genus-specific monoclonal
antibody. For this study, three rabbits were chosen for immunisation using
recombinant proteins, and three polyclonal rabbit sera (anti- Neospora NcSAG1, anti-
Neospora-NcSRS2, anti- Toxoplasma TgSRS2) were generated. Each polyclonal sera
was shown to be specific, and results showed that the sera can be used in
immunohistochemical detection of the parasite on formalin fixed paraffin embedded
samples.
For monoclonal antibody production, mice were immunised with recombinant proteins
NcSRS2 and TgSRS2. Hybridoma clones were generated, and clones that showed
reactivity and specificity using ELISA and immunohistochemistry were selected to
produce monoclonal antibodies. The study achieved the successful production of
Neospora monoclonal antibody ME7.1.B12.C9. No Toxoplasma specific monoclonal
antibody was produced. This study shows that the genus-specific PCR assays and
genus-specific antibodies can be used for the identification of Neospora, Toxoplasma
and Sarcocystis in formalin fixed paraffin embedded samples
Characterization of Immune System Cell Subsets in Fixed Tissues from Alpine Chamois (Rupicapra rupicapra)
No full textImmune system cell subsets in lymph nodes and spleen from alpine chamois (Rupicapra rupicapra subspecies rupicapra) living in the Italian Alps were characterized immunohistochemically. Seven primary antibodies (against human CD3, CD79αcy, CD68, or ovine CD4, CD8, CD21 and γδ T-cell receptor [TCR] epitopes) were tested on tissues fixed either in formalin or in zinc salts (ZS) and cross-reactivity with chamois immune cell epitopes was shown. ZS fixation allowed wider identification of immune cells, without the need for antigen retrieval. CD4+ and CD21+ cells were labelled only in ZS-fixed tissues. Reagents specific for human CD3, CD79 and CD68 antigens successfully detected chamois immune cells, both in ZS-fixed and formalin-fixed tissues. The reactivity and distribution of immune cells in lymph nodes and spleen were similar to those described in other domestic and wild ruminants. Results from this study may allow future investigation of the immune response and pathogenesis of diseases in the chamois
Immunopathogenesis of bovine neosporosis throughout gestation
No full textTesis para obtener el grado de Doctor of Philosophy, del College of Medicine and Veterinary de University of Edinburgh, 2013.Despite Neospora caninum being recognised as a major cause of bovine abortion, its pathogenesis is only partially understood. Evidence of immune mediated placental pathology has been reported as being responsible for compromising pregnancy probably due to an exacerbated Th1 immune response at the maternal-foetal interface. Different clinical outcomes are known to follow experimental infections at different stages of gestation, with foetal death being the most common finding during early gestation infections, and the birth of live congenitally infected calves following infection in mid or late gestation. The aim of the current study was to characterise the placental cellular immune responses and cytokine expression following experimental Neospora infection during pregnancy. Placentomes were collected from cattle experimentally inoculated with the tachyzoites of the Nc-1 strain during early, mid and late gestation.
Inflammation in early gestation was generally moderate to severe. Differently in mid gestation, inflammation was mild to moderate and minimal to mild in late gestation. Generally cellular infiltrates were mainly characterised by the presence of CD3+, CD4+ and γδ T-cells; whereas CD8+ and NK cells were less numerous. Macrophages were detected in larger numbers during later time-points after infection. A moderate to severe infiltration of IL-12, IFN-γ and TNF-α expressing cells was observed in the placentas collected in early gestation. This infiltration was more pronounced in the samples of placentome collected from dams carrying a dead foetus or in those that had aborted, compared with mothers carrying live foetuses at the time of sampling.
The distribution of the cellular subsets observed in the three studies was similar. However, cellular infiltrates were more severe following infection during the first trimester in comparison to the second and third trimester. Similarly, the infiltration of Th1 cytokine expressing-cells was more severe in early gestation compared with the milder and more minimal infiltrations observed following N. caninum infection in mid and late gestation, respectively. These results may explain the milder clinical outcome observed when animals are infected in later stages of pregnancy.EEA BalcarceFil: Cantón Germán José. Instituto Nacional de Tecnología Agropecuaria (INTA) Estación Experimental Agropecuaria Balcarce; Argentin
Characterization of CD79acy + cells in placentas from ruminants
No full textPrevious work carried out to characterise different immune cells in ruminant placentas found strong CD79αcynuclear labelling in cells histologically resembling trophoblast cells. In the attempt to characterize this cellpopulation, placentomes collected from cattle, sheep and water buffaloes were examined by im-munohistochemistry with single and double labelling using monoclonal antibodies (mAb) against B lymphocytesand trophoblast cells. Most CD79αcy+ cells co-expressed placental lactogen or cytokeratin and were CD21 andMHC class II negative strongly suggesting they do not have a B cell origin. However, a potential immunologicalrole of these cells cannot be ruled out and it is currently unknown if thefindings desEEA BalcarceFil: Cantón, Germán José. Pentlands Science Park. Moredun Research Institute; Gran Bretaña. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Schock, Alex. Pentlands Science Park. Animal and Plant Health Agency (APHA) Lasswade; Gran BretañaFil: Melo de Sousa, Noelita. University of Liège. Faculty of Veterinary Medicine. Physiology of Reproduction; BélgicaFil: Beckers, Jeans Francois. University of Liège. Faculty of Veterinary Medicine. Physiology of Reproduction; BélgicaFil: Chianini, Francesca. Pentlands Science Park. Moredun Research Institute; Gran Bretañ
Characterization of Immune Cell Infiltration in the Placentome of Water Buffaloes (Bubalus bubalis) Infected with Neospora caninum During Pregnancy
No full textNeospora caninum infection in cattle stimulates host immune responses, which may be responsible for placental damage leading to abortion. Susceptibility of water buffaloes (Bubalus bubalis) to neosporosis is not well understood, although vertical transmission and fetal death have been documented. The aim of this study was to characterize the immune response in the placentome of water buffalo following experimental infection in early gestation with the Nc-1 strain of N. caninum. Placentomes were examined by immunohistochemistry using antibodies specific for T-cell subsets, natural killer cells and CD79acy cells. Placental inflammation was characterized by the infiltration of CD3+ and CD4+ T cells and T cells expressing the gd T-cell receptor. The distribution of these cellular subsets in buffalo placentomes was similar to that previously described in cattle infected with N. caninum in early gestation, but the lesions were milder, which may explain the lower number of abortions observed in this species after infection.Fil: Cantón, G. J.. Moderun Research Institute; Reino Unido. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Konrad, José Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste; ArgentinaFil: Moore, Dadin Prando. Biomathematics and Statistics Scotland (BioSS); Reino Unido. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Caspe, S. G.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Palarea Albaladejo, J.. Biomathematics and Statistics Scotland (BioSS); Reino UnidoFil: Campero, C. M.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Chianini, F.. Moderun Research Institute; Reino Unid
Pathogenesis of scrapie in ARQ/ARQ sheep after subcutaneous infection: effect of lymphadenectomy and immune cell subset changes in relation to prion protein accumulation.
No full textAlthough it is well established that the infectious agent can replicate in the lymphoreticular system (LRS) early after inoculation, the information on pathways or cells involved in the dissemination of scrapie from the point of inoculation is limited. In order to gain a better understanding on these mechanisms 16 ARQ/ARQ, polymorphic or non polymorphic Suffolk or Romney lambs were inoculated subcutaneously with a Suffolk scrapie brain homogenate in the drainage area of the prefemoral lymph node. Fourteen lambs were then either subjected to early or late surgical removal of the prefemoral lymph nodes or not subjected to lymphadectomy and used as positive controls. Eleven animals were culled at a preclinical stage of the disease, and only 5, including 2 positive controls, were killed after reaching clinical end point. Of 5 polymorphic animals killed at preclinical stages of infection, two did not show any evidence of infection, two showed little involvement of LRS tissues and little or none in brain, and one showed widespread LRS involvement but mild PrPd accumulation in the CNS. This was in contrast with the findings in non-polymorphic sheep which, at comparable dpi, showed a complete attack rate with widespread PrPd accumulation in LRS tissues and many of them also in the CNS. The only polymorphic sheep left to develop clinical signs reached enpoint with a more protracted incubation period than the non-polymorphic sheep, but with similar PrPd magnitudes in the LRS or brain. The only change that appears to be related to PrPd accumulation in the LNs is the increase in CD21+ cells indistinctly in polymorphic or polymorphic animals
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