Tracheobronchial neuroendocrine carcinoma in a cat.

A tracheobronchial neuroendocrine carcinoma in a 10-year-old cat with a history of coughing, dyspnoea and anorexia is described. Endoscopic examination revealed a yellowish mass protruding into the trachea and partly obstructing the right bronchial lumen. Histological examination of biopsy samples revealed a hypercellular tumour consisting of sheets or ribbons of small hyperchromatic cells, with oval to spindle-shaped nuclei and minimal cytoplasm; nucleoli and mitotic activity were absent. The findings were confirmed on post-mortem examination. The small neoplastic cells were immunolabelled to varying degrees by antibodies against neuron-specific enolase, S-100 protein, synaptophysin and vimentin. Ultrastructural studies revealed scattered neurosecretory granules and scanty cellular junctional complexes, including desmosomes and tonofilaments, in neoplastic cells.

Granular cell tumour affecting the left vocal cord in a dog.

Granular cell tumours (GCTs) have been described in human vocal cords, but not in those of the dog. A single polyp in the left vocal cord, associated with laryngeal oedema and monolateral hyperplasia of the tonsil, was observed endoscopically in a 6-year-old male dog. Cytologically, the mass was characterized by well-defined polygonal cells, with granular cytoplasm and an eccentric nucleus. Histologically, the mass showed sheets of globoid to polygonal cells, filled with numerous diastase-resistant, periodic acid-Schiff-positive granules, and scanty stroma. Ultrastructurally, the granules were represented by heterogeneous lysosomes of variable size, suggesting a diagnosis of GCT. As reported in man, hyperplasia of the laryngeal and tonsillar epithelium and the presence of foci of pearl-like epithelial cells, mimicking invasive squamous cell carcinoma, were observed. Immunohistochemical examination revealed labelling of neoplastic cells for S-100 protein, CD68, collagen IV, and, focally, for glial fibrillary acidic protein, neuron-specific enolase and vimentin. These findings suggested a Schwann cell origin of the GCT.

Colostral transmission of maedi visna virus: sites of viral entry in lambs born from experimentally infected ewes.

Maedi visna virus (MVV) vertical transmission in sheep via infected colostrums is a very important route of infection in lambs. To verify colostral transmission and to study early viral entry in lambs, colostrum samples, and small intestine and mesenteric lymph nodes of lambs born from experimentally infected ewes were examined by histopathology, immunohistochemistry (IHC) and in situ hybridisation (ISH) studies. In particular, newborn lambs were naturally fed maternal colostrum and humanely killed at 10, 24, 48, 72, 96 h and 7 and 10 days after birth; two caesarian-derived lambs served as uninfected controls. No lesions suggestive of MVV infection were found, but marked immunoreactions for MVV capsid antigen (CA, p28) were detected in lambs fed maternal colostrum and in macrophages cultured from colostrum. IHC results in lambs suggest an initial viral absorption by intestinal epithelial cells at the tip of the villi, passage to mononuclear cells in the lamina propria and involvement of ileum Peyers' patches and mesenteric lymph nodes, with different staining patterns depending on infection times. ISH on intestinal sections of the 72 h lamb revealed the presence of proviral DNA in epithelial cells at the tip of the villi, suggesting a role for these cells in early MVV replication. The results contribute to knowledge about the pathogenesis of ovine lentivirus infection suggesting that the small intestine and mesenteric nodes are the sites of entry and propagation of MVV in lambs fed colostrums from infected ewes.

Association of Maedi Visna virus with Brucella ovis infection in rams.

Maedi Visna Virus (MVV) is the etiological agent of a systemic disease of sheep, which causes lesions in lungs, the central nervous system, joints, and mammary glands. It has been speculated that the association with Brucella ovis may lead to the venereal shedding of the virus. In this work, samples of epididymis from ten rams positive for MVV and infected experimentally with Brucella ovis, were subjected to liquid-phase PCR, immunohistochemistry (IHC) and in situ PCR tests, aimed at identifying the pathogens in a tissue context. IHC was carried out using a monoclonal antibody raised against p28 MVV protein and a polyclonal antibody to B. ovis. Liquid phase- and in situ PCR were designed to amplify a portion of MVV proviral DNA Pol sequence. In the animals showing B. ovis-related histopathological changes, IHC clearly demonstrated a positivity for B. ovis and MVV in interstitial and epithelial ductal cells. In situ PCR assessed the presence of MVV proviral DNA in macrophages and elements inside the epithelium. The unaffected and reagent control samples constantly gave negative results. Taken together, these data demonstrate that MVV may affect ovine epididymis, apparently taking advantage of the concurrent infection by B. ovis. The tropism of MVV for the epididymal epithelial cells, may be responsible for its excretion with the semen.

Experimental Maedi Visna Virus Infection in sheep: a morphological, immunohistochemical and PCR study after three years of infection.

A morphological, immunohistochemical and polymerase chain reaction (PCR) study was performed on eight ewes experimentally infected with an Italian strain of Maedi-Visna Virus (MVV) in order to evaluate the lesions and the viral distribution after three years of infection. At the moment of euthanasia, seven sheep were seropositive for MVV, while one sheep in poor body conditions was seronegative since one year. Lungs, pulmonary lymph nodes, udder, supramammary lymph nodes, carpal joints, the CNS, spleen and bone marrow of the eight infected sheep were collected for histology, for immunohistochemical detection of the MVV core protein p28 and for PCR amplification of a 218 bp viral DNA sequence of the pol region. The most common histological findings consisted of interstitial lymphoproliferative pneumonia and lymphoproliferative mastitis of different severity, while no lesions were observed in the CNS. MVV p28 antigen was immunohistochemically labelled in lungs, udder, pulmonary lymph nodes, spleen and bone marrow but not in the CNS of all the eight infected sheep. A 218 bp sequence of MVV pol region was detected in lung of a seropositive and of the seroconverted negative sheep. The results suggest that (i) MVV causes heterogeneous lesions in homogeneously reared ewes, (ii) MVV p28 antigen is detectable not only in inflammed target organs, but also in pulmonary lymph nodes, spleen and bone marrow, and (iii) immunohistochemistry and PCR are useful methods for Maedi-Visna diagnosis in suspected cases, also when serological tests are negative.

Cutaneous haemangiosarcoma in a sheep: morphological, histopathological and immunohistochemical observations.

Haemangiosarcomas of animals are reported mainly in the dog and cat and less commonly in the cow, horse, pig and goat, but no cases have been reported in sheep. These tumours occur more commonly in internal sites than in the subcutis. A large mass in the right flank of a 6-year-old Sardinian sheep showed histopathological features of a haemangiosarcoma. The antibodies anti-Factor VIII-related antigen (FVIII-RAg) and anti-CD31 did not react immunohistochemically with either the normal or the neoplastic endothelial cells, whereas endothelin-1 strongly labelled both the normal and the neoplastic cells at different stages of differentiation. The results emphasize the usefulness of endothelin-1 as a vascular marker in sheep, particularly in the immunohistochemical detection of neoplastic endothelial cells.

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.

Immunohistochemical study of lymphocyte populations infiltrating the gastric mucosa of beagle dogs experimentally infected with Helicobacter pylori.

Experimental infection of beagle dogs with Helicobacter pylori induces recruitment to the gastric mucosae of neutrophils at early stages and later of mononuclear cells that organize into lymphoid follicles. These structures become macroscopically evident and consist of peripheral CD4(+) T lymphocytes and central CD21(+) B lymphocytes. Furthermore, transient expression of interleukin-8 (IL-8) parallels the presence of neutrophils in the gastric mucosae, whereas expression of IL-6 tends to persist chronically.

Proviral DNA in the brains of goats infected with caprine arthritis-encephalitis virus.

Archive paraffin wax-embedded sections of brain from goats and kids naturally infected with caprine arthritis-encephalitis virus (CAEV) were examined. Severe leucoencephalitis was present, with infiltration of lymphocytes, plasma cells and macrophages into the white matter, meninges and choroid plexus. On both CAEV-positive and negative (control) tissues, in-situ polymerase chain reactions were used to amplify a DNA sequence specific to the proviral Pol region. In the infected tissues, strong hybridization signals were observed, mainly located in macrophages, microglial cells, astrocytes and oligodendrocytes, and in the ependymal epithelium and choroid plexus. Positive areas were also found in the spinal cord in endothelial cells of small blood vessels. Some neurons showed a positive reaction.

Epididymitis by Brucella ovis: experimental infection in virgin ram lambs.

Ten sexually immature rams were experimentally infected with Brucella ovis, to verify the antibody kinetics and its localization in urinary and genital tracts. All animals became positive to the complement fixation test from the 2nd post infection (p.i.) week and reached the maximum titre (1:256) on the 4th p.i. week. Bacteriemia was demonstrated on 3rd, 4th and 5th p.i. weeks. Two animals, respectively slaughtered 11 and 13 weeks after the infection, showed macroscopic and microscopic genital lesions and the etiologic agent was cultured from their urine and genital organs.

A conventional beagle dog model for acute and chronic infection with Helicobacter pylori.

Helicobacter pylori has been widely recognized as an important human pathogen responsible for chronic gastritis, peptic ulcers, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Little is known about the natural history of this infection since patients are usually recognized as having the infection only after years or decades of chronic disease. Several animal models of H. pylori infection, including those with different species of rodents, nonhuman primates, and germ-free animals, have been developed. Here we describe a new animal model in which the clinical, pathological, microbiological, and immunological aspects of human acute and chronic infection are mimicked and which allows us to monitor these aspects of infection within the same individuals. Conventional Beagle dogs were infected orally with a mouse-adapted strain of H. pylori and monitored for up to 24 weeks. Acute infection caused vomiting and diarrhea. The acute phase was followed by polymorphonuclear cell infiltration, interleukin 8 induction, mononuclear cell recruitment, and the appearance of a specific antibody response against H. pylori. The chronic phase was characterized by gastritis, epithelial alterations, superficial erosions, and the appearance of the typical macroscopic follicles that in humans are considered possible precursors of MALT lymphoma. In conclusion, infection in this model mimics closely human infection and allows us to study those phases that cannot be studied in humans. This new model can be a unique tool for learning more about the disease and for developing strategies for treatment and prevention.

Mortality in black siskins (Carduelis atrata) with systemic coccidiosis.

Ninety-five (97%) of 98 black siskins (Carduelis atrata) died within 2 months of arrival in Italy from South America with the following clinical sings: rapid weight loss, breast muscle atrophy, congested and distended abdomen, diarrhea, and lethargy. Macroscopically we observed hepato-splenomegaly, pulmonary congestion, and thickening of the interstinal wall. Histologically, lymphomonocytic transmural enteritis, interstitial mononuclear cell infiltrates in the lungs and in the liver, as well as activation of splenic follicles were common features. Large numbers of protozoa belonging to Isospora sp. were observed in various stages of their life-cycle in the intestinal epithelium, and some zoites were found in the extra-intestinal cellular infiltrate as well. No viral or bacterial pathogens were found.

Leptospira interrogans in the genital tract of sheep. Research on ewes and rams experimentally infected with serovar hardjo (hardjobovis).

To verify if Leptospira hardjo can colonize the male and female genital organs of sheep, 9 animals (6 non pregnant ewes and 3 mature rams) were infected with a strain of L. hardjobovis recently recovered from the kidneys of a seropositive ewe. Postinfection controls (bacteriologic, serologic, immunohistochemistry and electron microscopy) failed to disclose the presence of leptospires in the uterus and oviducts, testicles, epididymis, prostate and bulbourethral glands of animals used for the experiment and slaughtered from 37 to 242 postinfection days. All animals showed a renal localization of L. hardjobovis lasting for the entire period of the study (over 8 months). These results emphasize the important role of sheep as maintenance hosts of the serovar.

Ocular larva migrans and histopathological lesions in mice experimentally infected with Baylisascaris transfuga embryonated eggs.

The ability of Baylisascaris transfuga larvae to cause ocular larva migrans (OLM) in mice was examined. Mice were given approximately 3500 infective eggs of B. transfuga per os. Their eyes were removed and examined either microscopically or histologically at various intervals post-infection. Larvae were recovered beginning 7 days after infection. Histologically, free larvae were observed in the posterior chamber and within the ocular membranes. Larval granulomas were present in the choroid with involvement of retinal layers. It was concluded that B. transfuga larvae have the ability to produce OLM in mice following oral infection and should be considered as possible agents of OLM in other animals and in human beings.

Visceral larva migrans in mice experimentally infected with Baylisascaris transfuga (Ascarididae: Nematoda).

Laboratory bred albino mice, weighing 20 to 25 g, were orally infected with 2000 Baylisascaris transfuga infective eggs each. Mice were randomly chosen and sacrificed on days 1, 2, 3, 10, 15, 24 and 70 post-infection. Samples of intestine, mesenteric lymph nodes, liver, lungs, heart, spleen, kidneys, uterus, brain and skeletal muscles were collected and processed for conventional histopathology. In the early infection the major necropsy findings were focal haemorrhages on the intestinal wall, liver, lungs and brain. Histologically, larvae were found in haemorrhagic areas. In the subacute-chronic infection white nodules were scattered through all the examined organs, except the brain. Histologically, the white nodules corresponded to granulomas containing larvae surrounded by lymphocytes, eosinophil leukocytes and macrophages. The migration of B. transfuga larvae in spleen, kidneys and uterus of infected mice appears to have not been reported by previous workers. The possible role of B. transfuga larvae in the Visceral Larva Migrans syndrome is discussed.

The protective action of a water poor in calcium on the liver and digestive apparatus of guinea-pigs chronically treated with 9-alpha-fluoro-16-beta-methylprednisolone.

An evaluation was made of the possibility of exerting a protective action by administering natural water with a very low saline content, equal to 22 mg/l (oligomineral water), during the course of prolonged treatment with 9-alpha-fluoro-16-beta-methylprednisolone. The study was carried out using guinea-pigs (66 animals in all, of both sexes, clinically healthy, and of standard weight), which were divided into four groups which received, respectively: 9-alpha-fluoro-16-beta-methylprednisolone and aqua fontis, 9-alpha-fluoro-16-beta-methylprednisolone and oligomineral water, aqua fontis by itself, and oligomineral water by itself. Examinations carried out after thirty-four days of experimentation showed that the histomorphological damage to the liver and the digestive apparatus caused by the cortisonic therapy appeared to be considerably reduced and possibly eliminated when this therapy was combined with adequate administration of oligomineral water, such as the one considered in the present experiment.