Somatostatin Receptor 2 Expression in Canine Meningioma.

The neuropeptide somatostatin (SST) plays an important regulatory role in the proliferation of normal and neoplastic cells. Five subtypes of somatostatin receptors (SSTRs), SSTR1-SSTR5, have been identified in human tumours. The SSTR2 subtype is identified most commonly in meningiomas. Long half-life SST analogues are now recommended for the systemic treatment of unresectable or radiation-refractory recurrent human meningiomas. In this study, SSTR2 expression was evaluated in 46 canine meningiomas; in 21 cases this was by immunohistochemistry and in 25 cases by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). In addition, SSTR2 expression was evaluated by immunocytochemistry, western blotting and RT-qPCR on primary cell cultures prepared from two canine meningiomas. SSTR2 immunohistochemical expression was observed in 17/21 cases (81%), and SSTR2 mRNA expression was detected in 14/25 cases (56%). SSTR2 protein and gene expression were not significantly correlated with the tumour histological subtype or grade. Overall, meningothelial meningiomas showed constant and diffuse SSTR2 immunohistochemical expression and the highest SSTR2 gene expression level compared with other subtypes. A tendency for loss of SSTR2 in high-grade meningiomas was observed in both immunohistochemical and RT-qPCR studies. About 90% of cultured canine meningioma cells showed SSTR2 expression. In both of the meningioma cell cultures, SSTR2 expression was also detected by western blotting and RT-qPCR. This study demonstrates for the first time that canine meningioma expresses SSTR2 and that this expression is maintained in vitro. Our results, while preliminary, provide encouragement for further studies aimed at finding novel medical treatment strategies for canine meningioma, especially for tumours that are not surgically accessible.

Nuclear Glycogen Inclusions in Canine Parietal Cells.

Nuclear glycogen inclusions occur infrequently in pathologic conditions but also in normal human and animal tissues. Their function or significance is unclear. To the best of the authors' knowledge, no reports of nuclear glycogen inclusions in canine parietal cells exist. After initial observations of nuclear inclusions/pseudoinclusions during routine histopathology, the authors retrospectively examined samples of gastric mucosa from dogs presenting with gastrointestinal signs for the presence of intranuclear inclusions/pseudoinclusions and determined their composition using histologic and electron-microscopic methods. In 24 of 108 cases (22%), the authors observed various numbers of intranuclear inclusions/pseudoinclusions within scattered parietal cells. Nuclei were characterized by marked karyomegaly and chromatin margination around a central optically empty or slightly eosinophilic area. The intranuclear inclusions/pseudoinclusions stained positive with periodic acid-Schiff (PAS) and were diastase sensitive, consistent with glycogen. Several PAS-positive/diastase-sensitive sections were further examined by transmission electron microscopy, also using periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining to identify polysaccharides. Ultrastructurally, the nuclear inclusions were composed of electron-dense particles that were not membrane bound, without evidence of nuclear membrane invaginations or cytoplasmic organelles in the nuclei, and positive staining with PA-TCH-SP, confirming a glycogen composition. No cytoplasmic glycogen deposits were observed, suggesting that the intranuclear glycogen inclusions were probably synthesized in loco. Nuclear glycogen inclusions were not associated with gastritis or colonization by Helicobacter-like organisms ( P > .05). Our findings suggest that nuclear glycogen inclusions in canine parietal cells could be an incidental finding. Nevertheless, since nuclear glycogen is present in several pathologic conditions, further investigations could be warranted to determine their true significance.

An outbreak of bovine besnoitiosis in beef cattle born in central Italy.

An outbreak of bovine besnoitiosis in three female, 15-18 months old beef cattle in central Italy is here described. All the animals were born in central Italy without any recent contact with imported animals. The animals were in poor body conditions and showed symptoms and clinical signs consistent with chronic besnoitiosis. The diagnosis was confirmed by histopathologic examinations of skin biopsies and whole body at necropsy, showing typical 50-100 µ cysts engulfing superficial dermis in skin and lamina propria in mucosae; lesions were confined to skin and respiratory mucosae, and cysts were not seen in any other tissue. Bovine besnoitiosis is rapidly spreading among European countries and in our case the affected animals were born in the farm and not recent admission was referred, so it is likely to consider this as an autoctone outbreak of the disease in Italy. This case, taken together with other recently reported ones, suggest to consider Italy among potentially endemic areas for bovine besnoitiosis.

Internal hydrocephalus and associated periventricular encephalitis in a young fox.

Marked lateral ventricular enlargement associated with atrophic cerebral cortex and periventricular encephalitis is described in a 2-month-old fox affected by disorientation, generalized ataxia, difficulty in walking, circling, and blindness. Clinical conditions progressed to stupor and spontaneous death within a few days. At necropsy, severe inflammatory and necrotizing lesions were observed in periventricular sites associated with diverticula and cleft formation in perithalamic areas and rhinencephalic cortex. Immunolabeling for Toxoplasma gondii, Neospora caninum, Encephalitozoon cuniculi, canine distemper virus, and rabies virus was negative. Given the presence of periventricular and choroidal neutrophilic/mononuclear cell infiltration, it is thought that a bacterial infection may have been the cause of the inflammatory lesions, with internal hydrocephalus secondary to the severe periventricular lesions. A similar condition has been previously reported in the pathogenesis of spontaneously occurring acquired canine hydrocephalus, but no viral or bacterial causes have been investigated to date.

Immunohistochemical identification and image analysis quantification of oestrogen and progesterone receptors in canine and feline meningioma.

Oestrogen and progesterone receptor expression has been detected in human meningioma; in canine and feline meningiomas, however, the identification of steroid receptors requires further investigation. Fourteen meningiomas obtained from nine dogs and five cats were examined immunohistochemically for oestrogen receptors (ORs) and progesterone receptors (PRs). The immunolabelling reaction was quantified by light microscopy and image analysis. ORs were expressed in low numbers in two feline meningiomas and in one canine meningioma. PRs were more numerous, with more extensive tissue labelling. Conventional linear regression analysis showed that OR expression was not significant as compared with PR expression. PR expression was lowest in meningiomas with a high proliferation index, as determined by Ki67 expression. Conventional linear regression analysis between PR and Ki67 concentration confirmed a significant indirect relationship.

Origin of enzootic intranasal tumor in the goat (Capra hircus): a glycohistochemical approach.

Enzootic intranasal tumor (EIT) appears glandular in type and has recently been classified as an adenocarcinoma of low malignancy. The aim of this study was to characterize the secretion of surface glycoconjugates (GCs) in EIT and in normal respiratory and olfactory mucosae of the goat by means of conventional and lectin histochemistry, in order to shed light on the histogenesis of EIT. Morphologic and ultrastructural investigations showed two growth types of EIT: i.e., tubular and papillary patterns. Conventional histochemistry revealed the presence of neutral and carboxylated GCs in the olfactory glands and in the tubular part of EIT, as well neutral and sulphated GCs in the respiratory glands and in the papillary part of EIT, suggesting that the papillary pattern tumor arises from the respiratory glands, whereas the tubular portion of EIT arises from the olfactory glands. Lectin histochemistry gave further information on the expressed GCs.

Immunohistochemical detection of virulence-associated Rhodococcus equi antigens in pulmonary and intestinal lesions in horses.

Two horses with Rhodococcus equi infection were examined post mortem by an immunohistochemical method (peroxidase-antiperoxidase; PAP) with a monoclonal antibody (Mab 10G5) to the 15-17 kDa antigen of R. equi. One of the horses was also examined bacteriologically, R. equi being isolated in culture. Immunolabelling with this Mab was marked and widespread. On the other hand, the immunohistochemical reactivity of infected macrophages with a polyclonal antibody specific for lysozyme was slight. Thus, Mab 10G5 would appear to be a useful diagnostic reagent in R. equi infection, with or without cultural confirmation.

Enzootic intranasal tumour of goats in Italy.

An outbreak of enzootic intranasal tumour (EIT) in a goat herd in Central Italy is described. From October 1990 to September 1992 41 tumors were diagnosed in goats ranging in age from 6 months to 6 years and of both the Alpine and Saanen breeds. Clinically the affected goats showed nasal discharge, facial swelling, sneezing and snoring respiration and weight loss. Post-mortem examinations revealed uni- or bilateral tumours of the olfactory mucous membrane. The neoplasms were classified as low grade adenocarcinomas. Ultrastructurally, retrovirus-like particles were observed in 10/10 tumours examined. Epidemiological and ultrastructural findings strongly suggest a viral aetiology for intranasal enzootic adenocarcinoma in the goats examined.

Course of primary candidiasis in T cell-depleted mice infected with attenuated variant cells.

Anti-CD4, anti-CD8, or anti-interferon-gamma (IFN-gamma) antibodies or combinations of them were administered in the early stages of chronic infection of mice with a Candida albicans live vaccine strain, and the animals were monitored for course of primary infection, development of delayed-type hypersensitivity, resistance to reinfection, production of interleukin 2 (IL-2) and IFN-gamma in vitro by splenic lymphocytes, and levels of IL-2 and IFN-gamma transcripts in these cells. CD4+ cell and IFN-gamma depletion resulted in the development of fatal candidiasis by the attenuated yeast vaccine. In contrast, either treatment alone modified the course but not the outcome of primary infection, though each prevented the development of resistance to reinfection. Our data thus indicate that both IFN-gamma and CD4+ cells participate in resistance to primary infection with attenuated yeast cells and are critical in the induction of persistent systemic anticandidal immunity.