Diffuse Pulmonary Adenocarcinoma with Micropapillary Growth Pattern in a Cat.

A 12-year-old female European shorthair cat was presented with severe dyspnoea. Echocardiography revealed hypertrophic cardiomyopathy and pleural effusion. The cat died from acute decompensated left heart failure. At necropsy examination, the lungs were diffusely congested and firm, with multifocal grey areas and sparse haemorrhages. No solid masses were detected. Histopathology revealed a diffuse neoplastic proliferation characterized by irregular growth along alveolar walls with a micropapillary pattern. Tumour cells were large, highly pleomorphic and intensely positive for pan-cytokeratin and CAM 5.2. Tumour growth was obscured by simultaneous lesions related to chronic pulmonary congestion and interstitial lung disease. Histological features were consistent with a diffuse invasive pulmonary adenocarcinoma with a micropapillary pattern of tumour growth. Differential diagnosis included large cell carcinoma, which is usually characterized by rosettes or solid clusters of cells occupying alveolar lumen. Extensive cytokeratin immunolabelling was helpful in the differentiation from histiocytic proliferative disease.

17-AAG and Apoptosis, Autophagy, and Mitophagy in Canine Osteosarcoma Cell Lines.

Canine osteosarcoma is highly resistant to current chemotherapy; thus, clarifying the mechanisms of tumor cell resistance to treatments is an urgent need. We tested the geldanamycin derivative 17-AAG (17-allylamino-17-demethoxygeldanamycin) prototype of Hsp90 (heat shock protein 90) inhibitors in 2 canine osteosarcoma cell lines, D22 and D17, derived from primary and metastatic tumors, respectively. With the aim to understand the interplay between cell death, autophagy, and mitophagy, in light of the dual effect of autophagy in regulating cancer cell viability and death, D22 and D17 cells were treated with different concentrations of 17-AAG (0.5 µM, 1 µM) for 24 and 48 hours. 17-AAG-induced apoptosis, necrosis, autophagy, and mitophagy were assessed by transmission electron microscopy, flow cytometry, and immunofluorescence. A simultaneous increase in apoptosis, autophagy, and mitophagy was observed only in the D22 cell line, while D17 cells showed low levels of apoptotic cell death. These results reveal differential cell response to drug-induced stress depending on tumor cell type. Therefore, pharmacological treatments based on proapoptotic chemotherapy in association with autophagy regulators would benefit from a predictive in vitro screening of the target cell type.

Unexpected Cardiac Death During Anaesthesia of a Young Rabbit Associated with Fibro-fatty Replacement of the Right Ventricular Myocardium.

A 6-month-old female pet rabbit was presented for routine ovariectomy. The pre-anaesthetic evaluation was unremarkable and no anaesthetic complications occurred during the procedure. However, at the end of the surgery, the rabbit suddenly showed acute bradycardia and cardiac death. Necropsy examination revealed marked dilation of the right ventricle, associated with diffuse thinning of the right ventricular free wall. Gross and histopathological findings were suggestive of a congenital dilated cardiomyopathy characterized by fibro-fatty replacement of the right ventricular myocardium. Similar myocardial lesions have not been previously described in rabbits, although they have been documented in myocardial diseases of man, dogs, cats, cattle, horses and chimpanzees.

HSP32 and HSP90 Immunoexpression, in Relation to Kit Pattern, Grading, and Mitotic Count in Canine Cutaneous Mast Cell Tumors.

Literature data indicate heat shock protein (Hsp) 32 and 90 as potential molecular targets in canine neoplastic mast cells (MCs). However, their immunoexpression patterns in canine mast cell tumors (MCTs) have not been investigated. Thus, the aim of this study was to evaluate the immunohistochemical expression of Hsp32 and Hsp90 in 22 canine cutaneous MCTs, in relation to KIT immunolabeling pattern, histological grade, and mitotic count. All cases showed cytoplasmic labeling of Hsp90, variably associated with nuclear and/or membranous labeling. Relationships of Hsp90 or Hsp32 immunolabeling with KIT pattern, mitotic count, and tumor grade were not observed. However, the reduced Hsp32 immunoexpression observed in most grade III/high-grade MCTs suggests a tendency toward a loss of immunosignal in poorly differentiated MCs. The great heterogeneity in extent and distribution of Hsp90 immunoexpression among the different MCT cases may also partially explain the difficulties in predicting the in vivo biologic activity of Hsp90 inhibitors on canine MCTs.

Immunohistochemical expression of heat shock proteins, p63 and androgen receptor in benign prostatic hyperplasia and prostatic carcinoma in the dog.

This study compared heat shock proteins Hsp60, Hsp72 and Hsp73, along with p63 and androgen receptor (AR) immunoexpression between 16 cases of benign prostatic hyperplasia (BPH) and 11 prostatic carcinomas (PCa) in dogs. The proportion of Hsp60-positive cells was higher in PCa compared with BPH (P = 0.033), whereas the frequency and intensity of Hsp73 immunostaining did not differ significantly between the two groups. Hsp72-immunostained nuclei formed a discontinuous layer along the basement membrane in BPH, whereas cells in this layer in PCa were negative or weakly positive. Hsp72 nuclear score showed significant positive associations with both p63 (P = 0.016) and AR (P = 0.009) scores. Double immunofluorescence revealed Hsp72-p63 and Hsp72-AR co-expressions in basal cell nuclei. Aberrant cytoplasmic p63 immunolabelling was observed in 3 of 11 PCa cases. These results suggest a role of the combined expression of Hsp72, p63 and AR in basal epithelial cells in canine BPH and PCa.

Survivin and related proteins in canine mammary tumors: immunohistochemical expression.

Survivin is reexpressed in most human breast cancers, where its expression has been associated with tumor aggressiveness, poor prognosis, and poor response to therapy. Survivin expression was evaluated in 41 malignant canine mammary tumors (CMTs) by immunohistochemistry, in relation to histological grade and stage, and correlated with that of some related molecules (ß-catenin, caspase 3, heat shock proteins) to understand their possible role in canine mammary tumorigenesis. An increase in nuclear survivin expression, compared with healthy mammary glands, was observed in CMTs, where nuclear immunolabeling was related to the presence of necrosis. No statistically significant relation was found between the expression of the investigated molecules and the histological grade or stage. The present study may suggest an important involvement of survivin in CMT tumorigenesis. Its overexpression in most of the cases evaluated might suggest that targeting survivin in CMTs may be a valid anticancer therapy.

Cytological, histological and ultrastructural nuclear features of monster cells in a canine carotid body carcinoma.

A 7-year-old female Shih-tzu dog was presented with severe dyspnoea. A large mass was palpated in the left cranial neck. Cytological examination of an aspirate sample revealed cells with marked anisokaryosis, giant elements and many bare nuclei. Scattered intact giant cells showed scant, granular cytoplasm and intranuclear inclusions. Histologically, neoplastic cells were subdivided into lobules by fine collagenous trabeculae. Numerous pleomorphic giant, or 'monster', cells were observed, showing a highly indented nuclear envelope, intranuclear cytoplasmic pseudoinclusions (ICPs) and 'ground-glass' nuclear appearance. Neoplastic emboli were present, but no distant metastases were detected grossly. Immunohistochemically, the neoplastic cells expressed synaptophysin and had variable expression of neuron-specific enolase and vimentin. The cells were negative for pan-cytokeratin, CAM 5.2, glial fibrillary acidic protein and S100. Nuclear abnormalities and cytoplasmic neurosecretory granules were noted ultrastructurally. These features were consistent with a diagnosis of carotid body carcinoma (chemodectoma). Monster cells with ICPs have not been documented previously in canine chemodectoma.

Heat shock protein 90 is associated with hyperplasia and neoplastic transformation of canine prostatic epithelial cells.

Heat shock protein 90 (HSP90) is a molecular chaperone that regulates critical signalling proteins of cancer development and progression. Abnormal levels of HSP90 have been observed in human prostatic carcinoma (PC), with prognostic and therapeutic implications. Since spontaneously arising canine PC is a valuable model for the human disease, the aim of this study was to evaluate the immunohistochemical expression of HSP90 in two normal canine prostates, 17 canine prostates with benign prostatic hyperplasia (BPH) and five canine prostates with PC. HSP90 was expressed in the cytoplasm of epithelial cells in all samples, with a significant increase in labelled cells in PCs. Nuclear labelling was observed occasionally in normal tissue, but was increased in BPH and PC. HSP90 immunoreactivity in preneoplastic lesions (proliferative inflammatory atrophy and prostatic intraepithelial neoplasia) was similar to that in PCs. Increased HSP90 expression in canine PCs suggests the involvement of this molecule in carcinogenesis and tumour progression, supporting HSP90 as a potential target for therapeutic intervention.

Immunohistochemical evaluation of heat shock protein expression in normal canine nerve and peripheral nerve sheath tumours.

Abnormal expression of heat shock proteins (HSPs) has been observed in many human neoplasms and such expression has prognostic, predictive and therapeutic implications. The aim of this study was to evaluate immunohistochemically the expression of HSP 27, HSP 32 and HSP 90 in normal canine peripheral nerves and in four benign and 15 malignant canine peripheral nerve sheath tumours (PNSTs). In normal nerve, all of the HSPs were detected in axons, epineurial fibroblasts and scattered Schwann cell bodies. Cytoplasmic expression of HSP 27 was more widespread and intense in benign PNSTs compared with malignant PNSTs (P <0.05). Widespread and intense nuclear expression of HSP 32 was also associated with benign tumours (P <0.01), while high HSP 90 immunoreactivity was detected in all tumours, suggesting that HSP 90 might represent a new therapeutic target.

Multiple congenital malformations in a dicephalic spur-thighed tortoise (Testudo graeca ibera).

A 22-day-old dicephalic spur-thighed tortoise (Testudo graeca ibera) died following a history of lethargy, anorexia and absence of defecation. The two heads were anatomically similar with independent reaction to external stimuli. The carapace showed doubled first and extra second vertebral scutes. Radiography and transplastronal ultrasonography, performed when the animal was alive, revealed two symmetrical stomachs and two asynchronous hearts. These findings were confirmed by necropsy examination. Oesophagus, liver, gallbladder and trachea were also duplicated. Other malformations included pyloric valve atresia of the left stomach, focal stenosis of the transverse colon and liver hypoplasia. Dicephalism rarely occurs in Testudinidae and its pathogenesis, still unclear, is discussed.

Use of electron microscopy to classify canine perivascular wall tumors.

The histologic classification of canine perivascular wall tumors (PWTs) is controversial. Many PWTs are still classified as hemangiopericytomas (HEPs), and the distinction from peripheral nerve sheath tumors (PNSTs) is still under debate. A recent histologic classification of canine soft tissue sarcomas included most histologic types of PWT but omitted those that were termed undifferentiated. Twelve cases of undifferentiated canine PWTs were evaluated by transmission electron microscopy. The ultrastructural findings supported a perivascular wall origin for all cases with 4 categories of differentiation: myopericytic (n = 4), myofibroblastic (n = 1), fibroblastic (n = 2), and undifferentiated (n = 5). A PNST was considered unlikely in each case based on immunohistochemical expression of desmin and/or the lack of typical ultrastructural features, such as basal lamina. Electron microscopy was pivotal for the subclassification of canine PWTs, and the results support the hypothesis that canine PWTs represent a continuum paralleling the phenotypic plasticity of vascular mural cells. The hypothesis that a subgroup of PWTs could arise from a pluripotent mesenchymal perivascular wall cell was also considered and may explain the diverse differentiation of canine PWTs.

Intracoelomic teratoma in a domestic duck (Anas platyrhynchos domesticus): a case report including immunohistochemistry and electron microscopy.

A female domestic duck (Anas platyrhynchos domesticus) suddenly died with abdominal distension and a large multilobulated mass within the coelomic cavity was found. Histologically and immunohistochemically, a benign mature tridermic teratoma was diagnosed and epithelial structures, cartilage, bone, myxoid tissue, adipocytes, muscle cells, cystic spaces lined by squamous epithelium, feather follicles, melanocytes and variable neural and glial differentiation were recognized. By electron microscopy, desmosomes, keratin bundles, dense core neurosecretory granules, aberrant Z-line material and Luse bodies were found. To our knowledge, this is the first report of tridermic benign intracoelomic teratoma of a duck in which an extensive immunohistochemical and electron microscopic examination has been performed and in which a common neural and glial differentiation has been demonstrated.

ß-catenin in canine skin: immunohistochemical pattern of expression in normal skin and cutaneous epithelial tumours.

In normal adult skin, ß-catenin is a structural component of the intercellular junction and the Wnt/ß-catenin pathway plays a key role in the regulation of cutaneous homeostasis, particularly in the maintenance of hair follicle stem cells. No data are available on the expression pattern of ß-catenin in normal canine skin and in canine cutaneous epidermal and follicular tumours. The present study used immunohistochemistry to determine ß-catenin expression in four samples of normal canine skin and 62 cutaneous epithelial tumours (14 epidermal, 30 follicular and 18 glandular). ß-catenin expression was localized to the nucleus of matrical and dermal papilla cells in anagen hair follicles and was also found in scattered cells of the outer root sheath, suggesting that these follicular epithelial cells may have a high proliferative potential. Nuclear labelling, considered a hallmark of activation of the Wnt/ß-catenin signalling pathway, was observed in canine follicular tumours with matrical differentiation (100% of cases of trichoepithelioma and pilomatricoma), suggesting that a possible mutation of the canine CTNBB1 gene may underlie these tumours. In contrast, malignant tumours (squamous cell carcinoma, basal cell carcinoma, sebaceous and apocrine gland carcinoma and epithelioma) were characterized by reduction/loss of ß-catenin membrane labelling compared with normal cutaneous epithelial cells and benign tumours, suggesting that reduction/loss of ß-catenin expression is important in the acquisition of the malignant phenotype and may have a role in the infiltration and metastasis of these tumours.

Congenital and acquired pathology of ovary and tubular genital organs in ewes: a review.

Advances in our understanding of ovarian cyclicity, pathogenesis of subfertility and/or infertility and reproductive pathology in food animals have frequently entailed examination of abattoir material. Despite the fact that most lesions in ewes are likely to be of relatively minor significance to fertility, results of previous studies suggest that lesions of the female reproductive system may represent a significant source of loss to sheep husbandry. The objective of this paper is to review the pathophysiology, the effects on reproductive efficiency and the key gross and histological diagnostic features of congenital and acquired pathology of ovary and tubular genital organs in ewes.

Activated platelet-derived growth factor beta receptor expression, PI3K-AKT pathway molecular analysis, and transforming signals in equine sarcoids.

The equine sarcoid is the most common dermatologic neoplasm reported in horses. Bovine papillomavirus (BPV) types 1 and 2 are associated with sarcoids, in which the expression of the major transforming oncoprotein (E5) is often recorded. The transformation activity of the virus is due to the binding of the E5 to the platelet-derived growth factor beta receptor (PDGFbeta-r). In the present study, we show by Western blot in 4 sarcoid samples and 3 normal equine skin samples that the PDGFbeta-r is more phosphorylated in sarcoid tissue than in normal skin (P < .001). Furthermore, the physical interaction between the activated receptor and the 85-kDa regulatory subunit (p85) of phosphatidylinositol-3-kinase (PI3K) is shown by coimmunoprecipitation. The PI3K-AKT-cyclin D3 molecular pathway downstream to the activation of the PDGFbeta-r is shown to be expressed, and the amount of the investigated molecules is higher than normal (P < .001), suggesting an activation of these effectors in sarcoids. Further, we demonstrate that phospho-JNK and phospho-JUN are more expressed in sarcoids than in normal skin. Our results provide new insights into the pathogenesis of equine sarcoids and support the validity of this in-vivo model to further characterize the molecular pathways underlying BPV E5-induced carcinogenesis.

Review paper: a review of the pathology of abnormal placentae of somatic cell nuclear transfer clone pregnancies in cattle, sheep, and mice.

Cloning of cattle, sheep, and mice by somatic cell nuclear transfer (SCNT) can result in apparently healthy offspring, but the probability of a successful and complete pregnancy is less than 5%. Failures of SCNT pregnancy are associated with placental abnormalities, such as placentomegaly, reduced vascularisation, hypoplasia of trophoblastic epithelium, and altered basement membrane. The pathogenesis of these changes is poorly understood, but current evidence implicates aberrant reprogramming of donor nuclei by the recipient oocyte cytoplast, resulting in epigenetic modifications of key regulatory genes essential for normal placental development. The purpose of this review is to provide an overview of the anatomic pathology of abnormal placentae of SCNT clones and to summarize current knowledge concerning underlying pathogenetic mechanisms.

Expression of platelet-derived growth factor-beta receptor and bovine papillomavirus E5 and E7 oncoproteins in equine sarcoid.

Equine sarcoids are benign fibroblastic skin tumours that are recognized throughout the world. Infection with bovine papillomavirus (BPV) types 1 and 2 has been implicated as a major factor in disease development; however, the cellular mechanisms underlying fibroblast transformation remain poorly defined. The present study further characterizes aspects of the association with BPV in 15 equine sarcoids. BPV DNA was demonstrated in 12/15 tumours collected from different areas of Italy. Nine of these 12 tumours expressed the BPV oncoproteins E5 and E7, but these oncoproteins were not expressed by normal equine cells. The BPV E5 protein is known to bind to the platelet-derived growth factor-beta receptor (PDGF-betaR) and this molecule was expressed by 11 of the 12 sarcoids in which E5 was demonstrated. These findings add further weight to the theory that BPV and the PDGF-betaR may have a role in the pathogenesis of this disease.

High levels of anandamide, an endogenous cannabinoid, block the growth of sheep preimplantation embryos by inducing apoptosis and reversible arrest of cell proliferation.

BACKGROUND: The process of implantation is mediated by various molecules, one of which is anandamide (AEA), a lipid signalling ligand belonging to the family of endocannabinoids. AEA exerts its effects on implantation by binding to the Type 1 Cannabinoid Receptor (CB1-R), expressed in both blastocysts and uterus. We wanted to know whether the endocannabinoid signalling system was present also in the sheep reproductive tract and which kind of effect(s) AEA had on the development of sheep blastocysts in vitro. METHODS: We analysed the expression and activity of the endocannabinoid system in sheep reproductive tracts and blastocysts. Hatched sheep blastocysts were then exposed to AEA and its effect(s) were determined by TUNEL assay and by measuring the rate of necrosis and 5-bromo-deoxyuridine incorporation. RESULTS: We show that the AEA signalling system is present in sheep and that high concentrations of AEA induce apoptosis and inhibit cell proliferation via a CB1-R-dependent mechanism. Indeed, AEA effects were blocked when sheep blastocysts were cultured in the presence of the CB1-R antagonist SR161417A. Moreover, AEA inhibition of cell proliferation was reversible, as arrested embryos resumed a normal growth rate upon AEA removal from the medium. CONCLUSIONS: Our results suggest that disturbed regulation of AEA signalling via CB1-R may be associated with pregnancy failure. AEA could lower the quality of blastocysts by inducing apoptosis and inhibiting cell proliferation, thus making them incompetent for implantation.