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J Comp Pathol [journal]
- Mycobacterium marinum Infection in Japanese Forest Green Tree Frogs (Rhacophorus arboreus). [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jul 18.
Four Japanese forest green tree frogs (Rhacophorus arboreus) were presented with emaciation, abdominal distention and ulcerative and nodular cutaneous lesions affecting the brisket, limbs, digits and ventral abdomen. Another three frogs had been found dead in the same tank 1 year previously. Necropsy examination of these seven frogs revealed splenomegaly and hepatomegaly, with multiple tan-yellow nodular foci present in the liver, spleen, heart, lungs, ovaries and kidneys. Microscopically, five frogs had necrosis and surrounding granulomatous inflammation in the liver, spleen, kidneys, lungs, intestine and ovaries, with numerous acid-fast bacilli in the areas of necrosis. Two frogs had granulomatous lesions in the lungs, liver, spleen, heart, coelomic membrane, stomach and intestinal wall. These lesions had no or minimal necrosis and few acid-fast bacilli. Mycobacterium spp. was cultured from three frogs and identified as Mycobacterium marinum by colony growth rate and photochromogenicity and DNA sequencing. This is the first report of M. marinum infection in Japanese forest green tree frogs.
- CD117 Expression Influences Proliferation but not Survival in Canine Mammary Tumours. [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jul 12.
CD117 is a transmembrane tyrosine kinase receptor encoded by the c-Kit proto-oncogene. The immunohistochemical expression of CD117 was examined in 49 specimens of canine mammary glands (eight normal/hyperplastic, 11 benign tumours and 30 malignant tumours). Expression was assessed as: (1) presence or absence of CD117; (2) membrane, cytoplasmic, or both, distributions; and (3) percentage of CD117-labelled cells. None of these three immunohistochemical parameters was correlated with the type of mammary tissue (i.e. normal, benign or malignant), histotypes or histological stage of malignant tumours, or survival. An association was observed between Ki67 index and all three CD117 labelling parameters only for malignant tumours, with a significant increase in proliferative activity in tumours expressing CD117, mainly with both cytoplasmic and membrane expression.
- Necrotizing and Eosinophilic Masticatory Myositis in Farmed Mink: a Preliminary Description. [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jul 9.
This report describes necrotizing and eosinophilic myositis affecting the masticatory muscles of a group of mink. Affected animals demonstrated sudden death with marked subcutaneous oedema over the dorsal head. The temporalis and masseter muscles were pale, swollen and friable. Histologic changes consisted of varying degrees of myodegeneration, myonecrosis and inflammation. Eosinophils were prominent in the inflammatory infiltrate. Similar to dogs, masticatory muscles in mink were found to contain unique type 2M fibres, suggesting a possible target for an immune response. Aerobic and anaerobic tissue cultures of the affected musculature revealed no significant pathogens. Histological and nutritional analyses were not typical of vitamin E/selenium deficiency. This case series supports the existence of a novel disease entity in mink with some features comparable with masticatory muscle myositis in dogs.
- Membranoproliferative Glomerulonephritis in a Calf with Nephrotic Syndrome. [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jul 5.
A 2-month-old Japanese black calf was presented with a history of weight loss, exophthalmos and subcutaneous oedema of the brisket. Urinalysis and serum biochemistry showed proteinuria and hypoproteinaemia suggestive of nephrotic syndrome. Microscopically, lesions in the kidney were characterized by proliferation of mesangial cells and diffuse thickening of the glomerular basement membranes with the appearance of double contours. Immune complex deposits were confirmed by electron microscopy and immunofluorescence using reagents specific for bovine immunoglobulin G, complement factor C3 and bovine viral diarrhoea virus (BVDV). Consequently, the glomerular lesion in this case was diagnosed as membranoproliferative glomerulonephritis. BVDV type 1 was detected in serum by nested reverse transcriptase polymerase chain reaction. Viral antigen was also identified in the glomeruli by immunofluorescence. These results suggest that BVDV may have been the cause of immune complex glomerulonephritis in this calf.
- Meningoencephalitis in a Dog Due to Trichosporon montevideense. [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jul 5.
Meningoencephalitis due to infection with Trichosporon montevideense was diagnosed in a 4-year-old dog with a brief clinical history of rapidly progressing neurological signs that culminated in a comatose state. No significant gross lesions were found at post-mortem examination. Microscopically, a few scattered areas of pyogranulomatous inflammation with a few small, non-pigmented fungal hyphae were found within the cerebrum surrounding the lateral ventricles. A Trichosporon sp. was identified through culture of the brain and species was determined via sequence analysis of the internal transcribed spacer region of the Trichosporon rRNA gene. DNA in-situ hybridization confirmed the diagnosis. This is the first reported case of Trichosporon-associated meningoencephalitis in a dog.
- Feline Coccygeal Teratoma: Immunohistochemical Characterization of Immature Tissue Components. [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jul 5.
Congenital teratomas arising in the coccygeal region have not been reported in domestic animals. This report describes a congenital coccygeal teratoma in a male Burmese cat. A round to oval expansile mass with solid and cystic areas was found ventral to the 5th to 7th caudal vertebrae. Microscopically, the tumour was composed of derivatives of all three primordial germ layers with neuroectodermal predominance. Immunohistochemical double labelling identified immature tissue components in combination with Sox2, a regulator of stem cell proliferation and differentiation. Few Sox2-positive cells co-expressed the neural crest stem cell markers vimentin and neurotrophin receptor p75(NTR). Not all Sox2- and p75(NTR)-positive cells expressed vimentin. An overlapping expression of vimentin-negative and Sox2-, p75(NTR)-positive cells and GFAP- and p75(NTR)-positive cells may indicate a transition stage from immature to mature non-myelinating Schwann cells. Periaxin-positive myelinating Schwann cells surrounding neurofilament-positive axons were observed. Sox2 was additionally expressed in immature odontogenic epithelial cells and in immature cells of endodermal origin. Sox2 was not observed in mature cells, with the exception of satellite glial cells and mucous glands. Despite the presence of immature tissue components, no recurrence was observed 1 year after surgical removal.
- Tumour Gastrin Expression and Serum Gastrin Concentrations in Dogs with Gastric Carcinoma are Poor Diagnostic Indicators. [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jul 5.
Hypergastrinaemia is observed commonly in human patients with gastric carcinoma and is associated with atrophic gastritis and Helicobacter pylori infection, both of which predispose to development of gastric tumours. Increased expression of gastrin is also described as a prognostic indicator for gastric carcinoma in man. Gastric carcinoma is rare in dogs and generally carries a grave prognosis. In this study, the expression of gastrin was investigated immunohistochemically in gastric biopsy samples from 64 dogs with gastric carcinoma. Serum gastrin concentrations were measured in 15 of these dogs and compared with those of seven healthy control dogs. Tumour tissue expressed gastrin in 8% (5/64) of the dogs with gastric carcinoma. There was no significant difference in serum gastrin concentrations between dogs with gastric carcinoma and healthy controls (P = 0.08). Expression of gastrin in gastric carcinomas is less common in dogs than in man and may therefore not be relied on as a prognostic marker in this species. Serum gastrin concentration alone is also not a useful biomarker for gastric carcinoma in dogs.
- Transmural Ileal Ganglioneuromatosis in a Young Boer Goat (Capra hircus). [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jun 26.
A diagnosis of transmural ileal ganglioneuromatosis was made in a 15-day-old goat that was found dead following a period of diarrhoea and inappetence. Grossly, the entire length of the wall of the ileum was pale and firm with a variably segmental to transmural thickening. Microscopically, the ileal transmural thickening was due to a diffuse proliferation of both ganglionic and glial cells forming cell nests or packets that infiltrated the wall and into the mesentery surrounding a mesenteric lymph node. The neoplastic ganglionic cells were immunoreactive for S100, synaptophysin and triple neurofilament, while the glial spindle cells were immunoreactive with glial fibrillary acidic protein, S100 and laminin confirming their Schwann cell identity. Nerve fibres expressing neurofilament protein 200 and phosphorylated neurofilament (SMI-31) were observed rarely. Ganglioneuromatosis is defined as diffuse exuberant proliferation of all components of the intestinal ganglionic plexuses. In man, the transmural form has more grave clinical consequences than a focal pattern and is commonly associated with germline mutations in the RET proto-oncogene. Whether there is any comparable molecular genetic abnormality in animals remains unknown; however, ganglioneuromatosis needs to be included in the differential diagnosis of tumours of the autonomic enteric nervous system.
- The Dog as a Natural Animal Model for Study of the Mammary Myoepithelial Basal Cell Lineage and its Role in Mammary Carcinogenesis. [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jun 26.
Basal-like tumours constitute 2-18% of all human breast cancers (HBCs). These tumours have a basal myoepithelial phenotype and it has been hypothesized that they originate from either myoepithelial cells or mammary progenitor cells. They are heterogeneous in morphology, clinical presentation, outcome and response to therapy. Canine mammary carcinomas (CMCs) have epidemiological and biological similarities to HBCs, are frequently biphasic and are composed of two distinct neoplastic populations (epithelial and myoepithelial). The present study evaluates the potential of CMCs as a natural model for basal-like HBCs. Single and double immunohistochemistry was performed on serial sections of 10 normal canine mammary glands and 65 CMCs to evaluate expression of cytokeratin (CK) 8/18, CK5, CK14, α-smooth muscle actin (SMA), calponin (CALP), p63 and vimentin (VIM). The tumours were also evaluated for Ki67 and human epidermal growth factor receptor (HER)-2 expression. A hierarchical model of cell differentiation was established, similar to that for the human breast. We hypothesized that progenitor cells (CK5(+), CK14(+), p63(+) and VIM(+)) differentiate into terminally-differentiated luminal glandular (CK8/18(+)) and myoepithelial (CALP(+), SMA(+) and VIM(+)) cells via intermediary luminal glandular cells (CK5(+), CK14(+) and CK8/CK18(+)) and intermediary myoepithelial cells (CK5(+), CK14(+), p63(+), SMA(+), CALP(+) and VIM(+)). Neoplastic myoepithelial cells in canine complex carcinomas had labelling similar to that of terminally-differentiated myoepithelial cells, while those of carcinomas-and-malignant myoepitheliomas with a more aggressive biological behaviour (i.e. higher frequency of vascular/lymph node invasion and visceral metastases and higher risk of tumour-related death) were comparable with intermediary myoepithelial cells and had significantly higher Ki67 expression. The majority of CMCs examined were negative for expression of HER-2. The biphasic appearance of CMCs with involvement of the myoepithelial component in different stages of cell differentiation may help to define the role of myoepithelial cells in the mammary carcinogenetic process and the heterogeneous nature of basal-like HBCs.
- The Recent European Isolate (08P178) of Equine Arteritis Virus causes Inflammation but not Arteritis in Experimentally Infected Ponies. [JOURNAL ARTICLE]
- J Comp Pathol 2014 Jun 26.
In the last two decades, outbreaks of equine viral arteritis (EVA) have been reported in Europe, but little is known about these European isolates of equine arteritis virus (EAV). EAV European strain (08P178, EU-1 clade) isolated from one of these recent outbreaks is able to cause clinical signs on experimental infection. The aim of the present study was to investigate the microscopical lesions induced by this isolate after experimental infection of ponies. Animals were killed at 3, 7, 14 and 28 days post infection (dpi). At 3 dpi, lesions were essentially restricted to the respiratory tract and intestines and were characterized by mild multifocal epithelial degeneration and associated mononuclear cell infiltration. Lesions were more severe at 7 dpi and by 14 dpi, respiratory lesions were even more severe and lymphoplasmacytic infiltrates extended to other organs. At 28 dpi, lesions were still present in the viscera. In all specimens the most prominent histological change was intraepithelial, subepithelial and perivascular lymphoplasmacytic infiltration, ranging from mild and multifocal to extensive and diffuse. No signs of arterial damage such as infarcts, haemorrhages or necrosis were found. In conclusion, infection of naïve animals with the European 08P178 strain of EAV is associated with inflammation, but not arteritis.