Historical control background incidence of spontaneous pituitary gland lesions of Han-Wistar and Sprague-Dawley rats and CD-1 mice used in 104-week carcinogenicity studies.

The aim of this study was to determine the range and incidences of spontaneous microscopic lesions of the pituitary gland in control Han-Wistar and Sprague-Dawley rats and CD-1 mice from 104-week carcinogenicity studies carried out between 1998 and 2010 at Charles River Edinburgh. In both strains of rats and in CD-1 mice, non-proliferative lesions of the pituitary gland were generally uncommon, excluding cysts/pseudocysts (6.42% in Han-Wistar rats, 5.85% in Sprague-Dawley rats, and 2.08% in CD-1 mice). Primary proliferative lesions were most frequently found in the pars distalis of the pituitary gland. Adenomas and carcinomas of the pars distalis were more common in Sprague-Dawley rats (49.33% and 2.85%, respectively) than in Han-Wistar rats (27.29% and 0.21%, respectively), and adenomas in both strains of rats and CD-1 mice exhibited a marked sex predisposition, with females more commonly affected.

Spontaneous and Dosing Route-related Lung Lesions in Beagle Dogs from Oral Gavage and Inhalation Toxicity Studies: Differentiation from Compound-induced Lesions.

This study was conducted to characterize lung microscopic lesions in control beagle dogs from inhalation and oral gavage toxicity studies, to determine differences associated with the route of administration, and to discuss distinguishing features from compound-induced lung lesions. Samples from 138 control dogs from oral gavage studies and 124 control dogs from inhalation (vehicle control) studies were evaluated microscopically. There was no significant sex-related difference in the incidence of all lesions. Perivascular mononuclear cell infiltration, centriacinar mixed cell infiltration, bronchopneumonia, subpleural septal fibrosis, and alveolar macrophage accumulation were the most common lesions. Aspiration pneumonia was more common in dogs from gavage studies, suggesting reflux after gavage dosing or accidental administration of test formulation as possible causes. Centriacinar mixed cell infiltration was more common in dogs from inhalation studies, suggesting mild irritation by the vehicles used. Vascular lesions, which included pulmonary arteriopathy and smooth muscle mineralization, were observed in a few animals. Some of the spontaneous lesions are similar to lesions induced by test compounds. Compared to spontaneous lesions, compound-induced lesions tend to be multifocal or diffuse, follow a pattern of distribution (e.g., centriacinar, perivascular, and interstitial), show a dose response in the incidence and severity, and may show cell-specific toxicity.

Historical control background incidence of spontaneous thyroid and parathyroid glands lesions of rats and CD-1 mice used in 104-week carcinogenicity studies.

The incidence and range of spontaneous thyroid and parathyroid glands findings were determined in control Han-Wistar and Sprague-Dawley rats, and CD-1 mice from 104-week carcinogenicity studies carried out between 1998 and 2010 at Charles River Edinburgh. In both strains of rats and in CD-1 mice, non-proliferative lesions of the thyroid or parathyroid glands were generally uncommon apart from some findings in CD-1 mice such as ultimobranchial duct/cyst (5.72%), follicular distension/dilatation (3.84%), and cystic follicles (3.53%). In Han-Wistar rats, thyroid proliferative lesions were slightly more frequent in males than in females, but in Sprague-Dawley rats, they were of similar incidence in both sexes. The most common findings overall in Han-Wistar and Sprague-Dawley rats were C-cell hyperplasia (48.11% and 36.56%, respectively) and adenoma (10.87% and 9.52%, respectively), follicular cell hyperplasia (4.21% and 0.91%, respectively) and adenoma (4.32% and 1.36%, respectively). Secondary neoplastic lesions either in thyroid or parathyroid gland were poorly represented.

Adrenal Gland Background Findings in CD-1 (Crl:CD-1(ICR)BR) Mice from 104-week Carcinogenicity Studies.

The authors performed a retrospective study to determine the incidences of spontaneous findings in the adrenal glands of control CD-1 mice. Data were collected from 2,163 mice from control dose groups in 104-week carcinogenicity studies carried out between 2000 and 2010. Adrenal gland nonproliferative lesions were more common in males than in females. In males, the most common nonproliferative lesions were cortical hypertrophy, cortical atrophy, pigment deposition/pigmentation, cysts, and extramedullary hematopoiesis. In females, the most common nonproliferative lesions were pigment deposition/pigmentation, extramedullary hematopoiesis, and cortical atrophy. Proliferative lesions were more common in females than in males. In both sexes, the most common proliferative lesions were subcapsular cell hyperplasia, focal cortical hyperplasia, and subcapsular cell tumor. Pheochromocytomas were uncommon in both sexes, with a slightly higher incidence in females, and the benign type was more frequent than the malignant type. Lymphoma was the most common metastatic tumor in both males and females, followed by histiocytic sarcoma and erythroid/myeloid leukemia. To the best knowledge of the authors, there are no recent reports on spontaneous pathological findings in the adrenal glands of CD-1 mice, and these results will facilitate the interpretation of background findings in carcinogenicity studies.

Incidences and Range of Spontaneous Lesions in the Eye of Crl:CD-1(ICR)BR Mice Used in Toxicity Studies.

The incidence and range of spontaneous pathology findings were determined in the eyes of male and female control Crl:CD-1(ICR)BR mice. Data were collected from 250, 430, 510, and 2,266 mice from control dose groups of 4-, 13-, 80- and 104-week studies, respectively, carried out between 2005 and 2013. Lesions of the eye were very rare in 4- and 13-week studies, uncommon in 80-week studies, and were of relatively higher incidence in 104-week studies. No sex predilection in the incidence of eye lesions was apparent. No neoplastic lesions were observed, and congenital lesions were very rare. The most common findings were cataracts, retinal degeneration, mineral deposits in the iris, keratitis, anterior uveitis, and mineral deposits in the corneal stroma. These lesions were observed only in animals from 80- and 104-week studies, except retinal degeneration which was observed in animals from all age-groups. There are no previous reports of mineral deposits in the iris in this strain of mice. It is hoped that reference to the incidences reported here will facilitate the differentiation of spontaneous lesions from compound-induced lesions in toxicology studies in this strain of mouse.

Spontaneous necrotizing sialometaplasia of the submandibular salivary gland in a Beagle dog.

A single mass was found on the left submandibular salivary gland at necropsy of a 15-month-old male commercially bred laboratory Beagle dog from a control dose group from a repeat toxicity study. Microscopically, the mass was composed of a well-demarcated area of coagulative necrosis surrounded and separated from the normal salivary gland tissue by a thick fibrovascular capsule. Necrosis was admixed with areas of hemorrhage, fibrin, edema, fibrinoid necrosis of the vascular tunica media, and thrombosis of small and large vessels. Within the necrotic tissue, there was marked ductal hyperplasia, and squamous metaplasia of duct and acinar epithelium. The mass was diagnosed as necrotizing sialometaplasia of the submandibular gland. Hyperplastic ductal elements and squamous metaplasia can be mistaken microscopically with squamous cell carcinoma. Therefore, pathologists should be aware of this lesion as to avoid errors in the diagnosis of this benign pathologic condition.

CXCR4 expression in feline mammary carcinoma cells: evidence of a proliferative role for the SDF-1/CXCR4 axis.

BACKGROUND: Mammary tumours frequently develop in female domestic cats being highly malignant in a large percentage of cases. Chemokines regulate many physiological and pathological processes including organogenesis, chemotaxis of inflammatory cells, as well as tumour progression and metastasization. In particular, the chemokine/receptor pair SDF-1/CXCR4 has been involved in the regulation of metastatic potential of neoplastic cells, including breast cancer. The aim of this study was the immunohistochemical defininition of the expression profile of CXCR4 in primary and metastatic feline mammary carcinomas and the evaluation of the role of SDF-1 in feline mammary tumour cell proliferation. RESULTS: A total of 45 mammary surgical samples, including 33 primary tumours (31 carcinomas and 2 adenomas), 6 metastases, and 4 normal mammary tissues were anlyzed. Tumor samples were collected from a total number of 26 animals, as in some cases concurrent occurrence of neoplasm in more than one mammary gland was observed. Tissues were processed for standard histological examination, and all lesions were classified according to the World Health Organization criteria. CXCR4 expression in neoplastic cells was evaluated by immunohistochemistry. The level of CXCR4 immunoreactivity was semi-quantitatively estimated as CXCR4 score evaluating both the number of positive cells and the intensity of staining. Six primary, fibroblast-free primary cultures were obtained from fresh feline mammary carcinomas and characterized by immunofluorescence for CXCR4 and malignant mammary cell marker expression. SDF-1-dependent in vitro proliferative effects were also assayed. CXCR4 expression was observed in 29 out of 31 malignant tissues with a higher CXCR4 score observed in 4 out of 6 metastatic lesions than in the respective primary tumours. In 2 benign lesions analyzed, only the single basaloid adenoma showed a mild positive immunostaining against CXCR4. Normal tissue did not show CXCR4 immunoreactivity. CXCR4 score was statistically significantly associated with the histological features of the samples, showing an increase accordingly with the degree of neoplastic transformation (from normal tissue to metastatic lesions). Finally, in the primary cultures obtained from 6 primary feline mammary carcinomas CXCR4 expression was detected in all cells and its activation by SDF-1 in vitro treatment caused a significant increase in the proliferation rate in 5 out of 6 tumours. CONCLUSIONS: These results indicate that malignant feline mammary tumours commonly express CXCR4, with a higher level in malignant tumours, and, in most of the cases analysed, metastatic cells display stronger immunoreactivity for CXCR4 than the corresponding primary tumours. Moreover, CXCR4 activation in primary cultures of feline mammary carcinomas causes increase in the proliferative rate. Thus, SDF-1/CXCR4 system seems to play a tumorigenic in feline mammary gland malignancy and in vitro cultures from these tumour samples may represent an experimental model to investigate the biological and pharmacological role of this chemokinergic axis.

An intra-abdominal malignant mesenchymoma associated with nonabsorbable sutures in a ferret (Mustela putorius furo).

A 6-year-old ferret (Mustela putorius furo) was presented with abdominal enlargement. Clinical examination revealed an intra-abdominal mass measuring approximately 5 cm in diameter. Abdominal survey radiographs revealed a sharply marginated mass with multifocal radiodense foci, suggestive of pathologic calcification. A complete blood cell count revealed a moderate, normocytic, normochromic, nonregenerative anemia. The mass was surgically removed en bloc, fixed in 10% neutral buffered formalin solution, and routinely processed for histologic and immunohistochemical investigation. The neoplastic tissue consisted of a mixed neoplastic cell population, including osteosarcoma and fibrosarcoma components. Immunohistochemistry revealed that both neoplastic cell populations were positive for vimentin and negative for actin (smooth and striated), desmin, and myoglobin. Nonabsorbable suture material was admixed with the neoplastic tissue in the histologic section. This material was birefringent when viewed microscopically under polarized light.

A case of interscapular fibrosarcoma in a dwarf rabbit (Oryctolagus cuniculus).

A 1-year-old, intact, male dwarf rabbit (Oryctolagus cuniculus) was vaccinated against myxomatosis and rabbit viral hemorrhagic disease in February 1999, and a localized reaction appeared in the same anatomic site within a few days. No regression was observed after subcutaneous antibiotic treatment. The rabbit was kept under observation, and the swelling apparently disappeared in 3 months. The owner then decided to avoid any further subcutaneous drug administration. The referring veterinarian examined the animal on July 2006 for the sudden appearance of a nodular, 4.5 cm x 3.5 cm x 2.0 cm, subcutaneous mass located over the interscapular space. Fine-needle aspiration was performed, and a population of neoplastic spindle cells, rare pleomorphic multinucleated cells, and rare leukocytes were observed. The mass was surgically removed, fixed in 10% neutral buffered formalin, and routinely processed for histologic, histochemical, and immunohistochemical diagnostic investigation. The neoplastic tissue exhibited fascicles composed of malignant spindle-shaped cells with elongated to oval hyperchromatic nuclei and scant cytoplasm. Occasional multinucleated cells were also observed. The neoplastic cells were immunoreactive for vimentin but did not stain for smooth muscle actin, desmin, myoglobin, and cytokeratins (AE1/AE3). Moreover, the histochemical stain for aluminum was positive. The diagnosis was fibrosarcoma based on morphologic and immunohistochemical results. The histologic features of this neoplasm were remarkably similar to feline injection-site sarcoma.

Immunohistochemical evaluation of STAT3-p-tyr705 expression in feline mammary gland tumours and correlation with histologic grade.

STAT3 (signal transducer and activator of transcription 3) is a cytoplasmic transcription factor that plays a role in the G1 to S phase cell-cycle transition and is induced by cytokines and growth factors. The expression of STAT3 phosphorylated on tyrosine 705 (STAT3-p-tyr705) in normal, hyperplastic and neoplastic feline mammary gland tissue was assessed by immunohistochemistry in 45 cats. The samples included 4 normal mammary non-lactating tissues, 9 hyperplastic tissues (5 fibroepithelial hyperplasia and 4 lobular epithelial hyperplasia), 2 benign tumours (1 complex adenoma, and 1 simple adenoma), and 30 carcinomas (18 simple tubular papillary, 6 simple tubular, 2 simple solid, 3 cribriform, and 1 adenosquamous carcinoma). For immunohistochemistry, tissue sections were incubated with an anti-STAT3-p-tyr705 monoclonal antibody and visualized with EnVision-DAB polymer. STAT3-p-tyr705 positivity was quantified in a semi-quantitative manner. All positive samples showed cytoplasmic and/or nuclear positivity. Normal non-lactating mammary tissue showed a low number of positive cells, similar to hyperplastic tissue. In neoplastic tissues, a high number of positive cells with a moderate to intense reaction was observed. Moreover, a correlation was observed between nuclear positivity for STAT3-p-tyr705 and histologic grade (P=0.013; r=0.447), tubular formation (P=0.043; r=0.820), and mitotic activity (P<0.0001; r=0.689). In contrast, no such correlations were observed for cytoplasmic reactivity of STAT3-p-tyr705. A significant difference was observed between malignant lesions and hyperplasia with regards to expression of STAT3-p-tyr 705 in the cytoplasm (P=0.008; U=59.00) and nuclei (P=0.002; U=47.00). These results confirm previous our data and reinforce the potential role of STAT3 in malignancy as reported for human breast cancer and other sporadic tumours.

Immunodetection of the signal transducer and activator of transcription-3 in canine haemangioma and haemangiosarcoma.

The aim of this study was to examine the expression of signal transducer and activator of transcription 3 (STAT3) in canine haemangiomas and haemangiosarcomas. STAT3 protein was demonstrated in both the cytoplasm and nuclei of labelled cells. The expression of STAT3 was observed in 87.50% (35/40) of both haemangiomas and haemangiosarcomas and 72.22% (13/18) of haemangiomas and 100% (22/22) haemangiosarcomas. The percentage of positive cells in haemangiomas and haemangiosarcomas was statistically significant difference (P<0.0001). These preliminary results indicate that STAT3 is overexpressed in malignant tumours.

Clinical chemistry and haematology historical data in control Sprague-Dawley rats from pre-clinical toxicity studies.

The purpose of this paper is to provide historical data pertaining to clinical chemistry and haematology parameters, obtained from control Sprague-Dawley rats, used in pre-clinical toxicity studies. Mean, standard deviation, minimum and maximum values for haematological and coagulative profiles, haemato-biochemistry and urine analysis data, and the differences per sex and study duration, 4 versus 13 weeks, are presented. The studies were conducted in agreement with the GLP (Good Laboratory Practice) regulations. Statistically significant differences, at the confidence level of 99%, for the red blood cell (RBC) parameters, the white blood cell (WBC) series parameters, plasmatic albumin/globulin (A/G), alanine amino-transferase (ALT), alkaline phosphatase (ALP), creatinine, globulin, glucose, sodium, total protein, tryglycerides, urea and urine volume were observed in males, when 4-week study values were compared with those obtained from 13-week studies. Female rats showed statistically significant variations, at the confidence level of 99% for RBC number and mean corpuscular haemoglobin (MCH), mean red blood cell volume (MCV), WBCs count and lymphocytes percentage, A/G, albumin, ALT, AST, ALP, creatinine, globulin, and sodium, when 4-week study values were compared to 13-week studies. Similar differences were observed comparing the female with male haematological and biochemical data for the two different times of the sample collection. These data could be useful as a reference for evaluation of background pathology in Sprague-Dawley rats, when used in studies performed to evaluate the toxicological profile of a new chemical entity (NCE) in agreement with requirements from international regulatory agencies.

Undifferentiated tumor in the ovary of a corn snake (Elaphe guttata guttata).

A 6-year-old intact female corn snake (Elaphe guttata guttata) was presented with a 3-week history of anorexia. Coelomic radiographs revealed a 9 x 4 cm soft tissue opacity suggestive of a right ovarian enlargement. The mass (9 x 5 x 4 cm) was surgically removed, and multiple smears from tissue sections were stained with Diff-Quik. Multiple tissue samples from the mass were collected and fixed in formalin. Cytologic specimens were moderately cellular and contained light pink amorphous background material. The cells were primarily spindle-shaped with moderate to marked anisocytosis and anisokaryosis. Cells sometimes were round to polygonal, and rarely were arranged in small clusters. Macrophages occasionally were observed. Histologic specimens consisted of a highly cellular mass composed of pleomorphic, spindle-shaped cells and, occasionally, round to polygonal cells arranged in irregular fascicles. The neoplastic cells were immunoreactive for cytokeratin (AE1/AE3), smooth muscle actin, and skeletal muscle actin, but did not stain for vimentin or desmin. On the basis of the morphologic and immunohistochemical results, a diagnosis of ovarian undifferentiated carcinoma was made. In this report, we describe the challenges of using immunohistochemistry to diagnose this uncommon type of tumor in reptiles.

Fatal necrotizing fasciitis and myositis in a captive common bottlenose dolphin (Tursiops truncatus) associated with Streptococcus agalactiae.

A common bottlenose dolphin (Tursiops truncatus) was presented for necropsy after acute onset of gastrointestinal signs and cutaneous lesions that rapidly progressed to death. Gross and microscopic findings were characterized by locally extensive severe necrohemorrhagic fasciitis and cellulitis, and severe necrotizing myositis in the head and dorsocranial thorax, with numerous disseminated gram-positive cocci. Streptococcus agalactiae was isolated from the lesions and from visceral organs (liver and lung), and it was identified by standard microbiology techniques. This communication is the first report of necrotizing fasciitis in a marine mammal associated with S. agalactiae.

Surgery alone versus surgery and doxorubicin for the treatment of feline injection-site sarcomas: a report on 69 cases.

Sixty-nine cats were treated for injection-site sarcomas at the Veterinary Teaching Hospital of Grugliasco, Turin (Italy). The animals were divided into two subgroups: those subjected to four doxorubicin cycles combined with radical surgical excision 10 days after the second chemotherapy cycle (group A, 49 cats) or those treated with surgery alone (group B, 20 cats). Each cat was monitored for lung metastasis and local recurrence. In group A, 28 cats were alive at the end of the follow-up period. In this group, the recurrence rate was 40.8% while lung metastasis occurred in 12% of cats. In group B, eight animals were alive at the end of the follow-up period, while the rates of recurrence and metastasis were 35% and 10%. Neither the median disease-free interval nor the median overall survival was reached in either group. Moreover, there were no statistically significant differences between the two groups.

Bronchogenic adenocarcinoma in a cat: an unusual case of metastasis to the skin.

A 6-year-old, spayed, female, domestic shorthair cat was presented for decreased activity. A nodular lesion was found in the skin extending into the subcutaneous tissue of the right abdominal flank. On lateral and ventrodorsal radiographs of the thorax, an opacity involving the entire right caudal lung lobe and pleural effusion were noted. Cytologic evaluation of cells in the thoracic fluid and in the mass revealed a population of atypical epipthelial cells with marked anisocytosis and high N:C ratios, organized in acinar-like clusters. Multinucleated cells and several mitotic figures were found. The cytologic interpretation was carcinoma. Because of the progressive severity of clinical signs, the cat was euthanized. Histologic evaluation of tissues obtained at necropsy indicated a bronchogenic adenocarcinoma in the lung, with metastasis to the skin of the right flank, but no involvement of the digits. Based on immunohistochemical stains, the neoplastic cells strongly co-expressed cytokeratin and vimentin, and were negative for S-100 and actin-specific antigen. Bronchogenic adenocarcinoma is an uncommon neoplasm in cats, and the digits are the most common sites of metastasis. This case was unusual in that the skin of the abdominal wall was the primary site of metastasis, with no involvement of the digits.

Bone marrow spontaneous lesions in rodents from nonclinical 104-week carcinogenicity studies.

The authors performed a retrospective study to determine the incidences and range of spontaneous lesions in the bone marrow (sternum and femur) of control mice and rats. Data was collected from 2186 mice (Crl:CD-1(ICR)BR), and 2347 rats (Han Wistar and CD(SD) rats) from the control dose groups of 104-week carcinogenicity studies carried out between 2005 and 2014. The incidence of spontaneous lesions in the bone marrow was higher in mice than in rats, and in both species non-neoplastic lesions were more common than neoplastic lesions. In mice, the most common non-neoplastic lesions in the bone marrow were increased cellularity, pigmented macrophages, and decreased cellularity, and the most common neoplastic lesions were malignant lymphoma, granulocytic leukemia and histiocytic sarcoma. There were occasional sex and site differences (sternum marrow vs femur marrow) in the incidence of a few bone marrow lesions in mice. In rats, the most common non-neoplastic lesions were increased cellularity and stromal fibrosis, and the most common neoplastic lesion was malignant lymphoma. In rats, no sex predilection in the incidence of bone marrow lesions was apparent, and there were no significant site differences in the incidence of lesions. To the best knowledge of the authors, there are no recent reports on spontaneous pathological findings in bone marrow of rodents, and we believe that these results will facilitate the interpretation of background findings and/or their increased incidence in carcinogenicity studies.

Immunohistochemical detection of growth hormone (GH) in canine hepatoid gland tumors.

The aim of this study was to detect immunohistochemically means growth hormone (GH) in 24 hepatoid gland adenomas and 5 hepatoid gland carcinomas and to compare the difference of immunoreactivity between types of tumors. The tumors were classified according to the WHO standards. Tissue sections which were prepared from formalin-fixed, paraffin wax-embedded tissues from 25 male and 4 female dogs were carried out immunostaining using polyclonal primary anti-hGH and EnVision method. Of 24 hepatoid gland adenomas (perianal gland adenomas) 23 (95.8%) were positive. All 5 hepatoid gland carcinomas (perianal gland carcinomas) were positive. No statistically significant differences in percentage of labelled cells between malignant and benign tumors were seen. The present demonstration of GH in hepatoid gland tumors adds new data on GH in extra-pituitary tissues and hormon-dependent tumors.