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  • Author or Editor: Miklós Rusvai x
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Claudin-5 is an endothelium-specific tight junction protein. The aim of the present study was to detect the expression pattern of this molecule in intact pancreatic tissues and in well-differentiated and poorly differentiated pancreatic acinar cell carcinomas from dogs by the use of cross-reactive humanised anticlaudin-5 antibody. The necropsy samples taken from dogs included 10 nonneoplastic pancreatic tissues, 10 well-differentiated pancreatic acinar cell carcinomas, 10 poorly differentiated pancreatic acinar cell carcinomas, 5 intrahepatic metastases of well-differentiated and 5 intrahepatic metastases of poorly differentiated acinar cell carcinomas. A strong lateral membrane claudin-5 positivity was detected in exocrine cells in all intact pancreas samples. The endocrine cells of the islets of Langerhans and the epithelial cells of the ducts were negative for claudin-5. The endothelial cells of vessels and lymphatic channels in the stroma of the intact pancreas showed strong membrane positivity for this claudin. All well-differentiated exocrine pancreas carcinomas and all poorly-differentiated pancreatic acinar cell carcinoma samples showed a diffuse loss of claudin-5 expression. The claudin-5-positive peritumoural vessels and lymphatic channels facilitated the detection of vascular invasion of the claudin-5-negative cancer cells. In liver metastasis samples, the pancreatic carcinomas were negative for claudin-5. It seems that the loss of expression of claudin-5 may lead to carcinogenesis in canine exocrine pancreatic cells.

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Complete genome sequences of bovine viral diarrhoea virus types 1 and 2 (BVDV-1 and 2) deposited in the GenBank were submitted to bioinformatic analysis using a recombination-detecting software. The results indicate that recombination events are not rare in the case of BVDV, which frequently causes immunotolerance and, consequently, persistent infection in calves. The lack of specific immunity provides an ideal possibility for multiple infections by antigenically related but genetically different BVDV strains, and hence recombinations may occur. Among the 62 BVDV-1 genomes five recombinants and their possible parent strains, while among the 50 BVDV-2 genomes one simple recombinant and its parent strains were identified, which were supported by extremely strong probability values (P values varying between 1.26 × 10–4 and 1.58 × 10–310). Besides the newly identified recombinants, recombination events described previously were confirmed, but in some of these cases former information was completed with new data, or different parent(s) were suggested by the programme (RDP 4.46 BETA) used in this study.

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The authors describe a case of unilateral adenocarcinoma emerging from the Harderian gland, filling the right orbital cavity of a Florida Red-bellied Turtle ( Pseudemys nelsoni ). The tumour did not produce any metastasis but presented an expansive growth and led to the dislocation and protrusion of the right eyeball. Histopathological analysis revealed the presence of numerous mitotic figures in the cellular population that made up the tumour. The tumour cells completely filled the alveoli of the gland and had a nest-like structure. The authors also emphasise the importance of the differential diagnosis of this rare pathological change in turtles. Epithelial hyperplasia of the Harderian gland’s duct, observed in animals suffering from vitamin A deficiency, can also lead to an enlargement of the eyelid, but in these cases the change usually involves both eyelids symmetrically. This is the first description of a Harderian gland adenocarcinoma in a Florida Red-bellied Turtle.

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Claudins are integral membrane proteins of the tight junction structures expressed by epithelial and endothelial cells. The present study has evaluated the expression of claudin-4 in 10 normal canine hepatoid glands and in 67 hepatoid glands with hyperplastic and neoplastic lesions. The lesions studied included normal hepatoid glands (n = 10), nodular hyperplasias (n = 10), adenomas (n = 12), epitheliomas (n = 15), differentiated carcinomas (n = 15) and anaplastic carcinomas (n = 15). There was an intensive expression of claudin-4 in normal canine hepatoid glands as well as in hyperplasias and adenomas. Claudin-4 was detected as a well-localised linear circumferential membranous staining pattern of epithelial cells (mature hepatoid cells) in normal hepatoid glands, perianal gland hyperplasias and adenomas. In nodular hyperplasia and adenoma, the reserve cells showed membrane positivity for the claudin-4 molecule. There was a weaker expression in hepatoid gland epitheliomas. In the epitheliomas, the basaloid reserve cells never expressed the claudin-4 molecule. The multiple small parts of epitheliomas in which the cells exhibited typical hepatoid features showed a well-localised linear circumferential membranous staining pattern for claudin-4. The numerical score for cellular expression of claudin-4 was higher in differentiated carcinomas than in epitheliomas, but moderately lower than in adenomas. The anaplastic, poorly differentiated hepatoid gland carcinomas showed an overexpression of claudin-4. These results suggest that low claudin-4 expression in epitheliomas is a molecular characteristic indicative of increasing cellular disorientation, detachment motility and invasion by tumour cells, and claudin-4 seems to be helpful in distinguishing undifferentiated carcinomas from differentiated carcinomas and epitheliomas of the hepatoid gland. In addition, claudin-4 can help distinguish epithelioma from differentiated carcinoma of the canine hepatoid gland.

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In this study, synchronous spontaneous, independent liver and gallbladder tumours were detected in a Bearded dragon (Pogona vitticeps). The multiple tumours consisted of intrahepatic cholangiocarcinoma as well as in situ adenocarcinoma and two adenomas of the gallbladder. The biliary epithelial cells and the cholangiocarcinoma showed membranous cross-immunoreactivity for claudin-7. The gallbladder epithelial cells, its adenoma and adenocarcinoma showed basolateral cross-reactivity for claudin-7. We think that the humanised anti-claudin-7 antibody is a good marker for the detection of different primary cholangiocellular and gallbladder tumours in Bearded dragons. The cholangiocytes, the cholangiocarcinoma, the endothelial cells of the liver and the epithelial cells and gallbladder tumours all showed claudin-5 cross-reactivity. The humanised anti-cytokeratin AE1–AE3 antibody showed cross-reactivity in the biliary epithelial cells, cholangiocarcinoma cells, epithelial cells and tumour cells of the gallbladder. It seems that this humanised antibody is a useful epithelial marker for the different neoplastic lesions of epithelial cells in reptiles. The humanised anti-α-smooth muscle actin (α-SMA) antibody showed intense cross-reactivity in the smooth muscle cells of the hepatic vessels and in the muscle layer of the gallbladder. The portal myofibroblasts, the endothelial cells of the sinusoids and the stromal cells of the cholangiocarcinoma and gallbladder tumours were positive for α-SMA. The antibovine anti-vimentin and humanised anti-Ki-67 antibodies did not show crossreactivity in the different samples from the Bearded dragon.

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Acta Veterinaria Hungarica
Authors: Csaba Jakab, Miklós Rusvai, Nóra Biró, Zoltán Szabó, Péter Gálfi and Janina Kulka

A 5-year-old female degu ( Octodon degus ) showed the clinical sign of metrorrhagia. During ovariohysterectomy a circumscribed tumoural lesion was found in the right uterine horn. The histopathological diagnosis of this soft tissue mass was primary benign cavernous angioleiomyoma of the uterus. During immunohistochemical analysis the neoplastic endothelial cells of this mixed mesenchymal tumour showed strong membrane positivity for the endothelial marker claudin-5 but were negative for CD31 (another endothelial marker). The endothelial cells of the internal positive control tissues such as intact peritumoural vessels were positive for claudin-5 but negative for the CD31 endothelial marker. As it has been described also in other species, it seems that claudin-5 is a better endothelial marker than CD31 for the detection of normal and neoplastic endothelial cells in different tissues of degus.

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Claudins are key tight junctional proteins between adjacent epithelial, mesothelial or endothelial cells, which are responsible for the permeability of the paracellular space. This paper describes that the endothelial cells of normal hepatic arterioles, portal venules and portal lymphatics as well as the endothelium of sinusoids from dogs show strong membranous claudin-5 cross-reactivity. In 25 liver biopsy samples taken from dogs with portal vein hypoperfusion, an increased number of arterioles was detected in the portal areas (PAs) by the use of humanised anti-claudin-5 antibody. The increased number of hyperplastic hepatic arterioles per PA was 5–6, 8–12 and 15–20 in the case of small, medium-sized and large PAs, respectively. It is suggested that the claudin-5 marker can improve the detection of hepatic arteriolar proliferation in the PAs of liver samples.

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Acta Veterinaria Hungarica
Authors: Zsolt Becskei, Sanja Aleksić-Kovačević, Miklós Rusvai, Gyula Balka, Csaba Jakab, Tamaš Petrović and Milijana Knežević

The lymphatic organs of 50 pigs from a total of eight farms located at different sites in the epizootiological region of North Bačka County were studied to obtain data on the prevalence of circoviral infections in Serbia. All of the pigs examined had clinical signs suggestive of postweaning multisystemic wasting syndrome (PMWS). All pigs underwent necropsy and tissue samples were taken for histopathological, immunohistochemical (IHC) and PCR analysis. The presence of porcine circovirus 2 (PCV2) was established by PCR analysis in the organs of the pigs tested. The most frequent histopathological lesions of lymphoid tissue linked with the presence of positive immunostaining for PCV2 Cap antigen confirmed the existence of PMWS in all farms tested in North Bačka County. Using PCR, histopathological and IHC techniques, the presence of PMWS was proved in the Republic of Serbia. During necropsy, generalised enlargement of the lymph nodes was evident. The most common histopathological finding was lymphocyte depletion in the follicular and perifollicular areas of lymph nodes. Infiltration by macrophages was also recorded. By IHC analysis, the cytoplasm of macrophages was shown to contain a large amount of the ORF2-coded Cap antigen of PCV2. Lymphocyte depletion and large numbers of macrophages were recorded in the tonsils, spleen, intestinal lymphatic tissue, Peyer’s patches and ileocaecal valve. The presence of typical granulomatous lesions with multinuclear giant cells (MGCs) was also recorded in the lymphatic tissue. Cap antigen was shown to be present in macrophages and less often in lymphocytes.

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Adenoviral nucleic acid was detected by polymerase chain reaction (PCR) in formalin-fixed paraffin-embedded tissue samples of a cat that had suffered from disseminated adenovirus infection. The identity of the amplified products from the hexon and DNA-dependent DNA polymerase genes was confirmed by DNA sequencing. The sequences were clearly distinguishable from corresponding hexon and polymerase sequences of other mastadenoviruses, including human adenoviruses. These results suggest the possible existence of a distinct feline adenovirus.

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Acta Veterinaria Hungarica
Authors: Elena Palade, Nóra Biró, Mihály Dobos-Kovács, Zoltán Demeter, Míra Mándoki and Miklós Rusvai

From a total of 1819 great tits ( Parus major ) ringed in 2007 in Pilis Mountains, Hungary, 15 birds presented nodular proliferative lesions on different areas of the head and eyelids, suggesting a poxvirus infection. Three birds were submitted for analysis. The presence of avipoxvirus infection was confirmed by histopathology, electron microscopy (EM) and a polymerase chain reaction (PCR) based technique. Nucleotide sequence analysis of a 428 base pairs (bp) fragment of the viral 4b core protein gene revealed 100% identity between two of the Hungarian isolates (PM9 HUN, PM33 HUN) and two great tit poxvirus strains isolated in Norway in 1973 (GTV A256, GTV A311). The third Hungarian isolate (PM34 HUN) was more closely related to a different Norwegian isolate (GTVA310) than to the Hungarian isolates. The nucleotide sequence analysis of a shorter fragment of the viral 4b core protein (227 bp) gene revealed 100% identity between the Hungarian isolates, the same Norwegian isolates and a great tit poxvirus strain detected in Austria in 2007.

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