Pathological Characterization and Risk Factors of Splenic Nodular Lesions in Dogs (Canis lupus familiaris).

In dogs, the spleen is a secondary lymphoid organ that can be affected by both neoplastic and non-neoplastic nodules. In general, few studies relate histopathological diagnosis to tumor size and the number of nodules in spleen biopsies. Some of these studies are inconclusive regarding the difference between neoplastic and non-neoplastic lesions and have small sample sizes or do not consider all splenic lesions. This study aimed to characterize splenic masses and determine risk factors for spleen tumors in dogs. A total of 507 histological reports corresponding to the diagnosis of splenic lesions in dogs from a private laboratory of animal pathology in the Metropolitan Region, Chile, were used. Data were analyzed by descriptive statistics and multiple logistic regression. The most frequent neoplastic and non-neoplastic diagnoses were hemangiosarcoma and hyperplasia, respectively. Most of the cases occurred in male (265 cases, 52.3%), senior (421 cases, 83%), and purebred individuals (342 cases, 67.5%). The most affected breeds were the Cocker Spaniel, German Shepherd, and Labrador Retriever. The most frequent lesion was a single nodule. The variables that exhibited a greater risk for the presentation of splenic neoplasia were male sex (odds ratio (OR) = 16.21; 95% confidence interval (CI) 1.741-150.879; p = 0.014), the presence of two or more splenic nodules (OR = 3.94; 95% CI 2.168-7.177; p < 0.001), an increase in nodule size greater than 2 cm (OR for quartiles 2, 3 and 4 of 2.2; 95% CI 1.036-4.941; p = 0.041, 2.9; 95% CI 1.331-6.576; p = 0.008, and 3.6; 95% CI 1.562-8.499; p = 0.003, respectively), and increasing age (OR = 1.23; 95% CI 1.048-1.436; p = 0.011). On the other hand, males exhibited a lower risk as age increases (OR = 0.76; 95% CI 0.615-0.928; p = 0.008). In conclusion, this study identified that males, multinodular presentation, nodule size, and age are risk factors for the occurrence of splenic neoplasia in dogs, knowledge that will contribute to the diagnostic management of dogs with spleen lesions.

Reproductive and Behavioral Evaluation of a New Immunocastration Dog Vaccine.

Canine immunocastration development has been of interest for many years as a complementary strategy to surgical castration. The purpose of this paper was to verify the effect of a recombinant vaccine for dog immunocastration. Two tests were done, one under controlled conditions and a second under field conditions. Animals were injected with 1 mL of 500 µg GnRXG/Q recombinant protein; 500 µg of low molecular weight chitosan as adjuvant; 1 mL NaCl 0.9% q.s. In the first trial, eight Beagle male dogs between the ages of 1 and 3 comprised the sample, randomly divided into two groups: vaccinated group (n = 7) and control group (n = 2). The second trial had 32 dogs with owners. In the first controlled conditions trial, the vaccine produced specific antibodies that remained until the end of the trial (day 270), inducing reduced testosterone and spermiogram changes in the immunized animals. In a second trial, on the field, specific immunity was induced, which remained high up to day 150. The vaccine also reduced sexual agonistic and marking behaviors. This new vaccine proved to be safe, immunogenic, capable of reducing gonadal functionality, and had a positive effect on inducing reduced sexual, agonistic, and marking behavior of the animals.

Oral masses in African pygmy hedgehogs.

African pygmy hedgehogs (Atelerix albiventris) frequently develop oral neoplasms, and most of these neoplasms are malignant. We characterized oral masses detected in hedgehogs at clinical examination. During a 1-y period, we diagnosed oral cavity masses in 27 privately owned hedgehogs; 16 were female and 11 were male, with ages of 2-7 y (mean: 4.3 y). Eight masses were non-neoplastic and were diagnosed as gingival hyperplasia (GH). Nineteen masses were neoplastic, of which 17 were squamous cell carcinomas (SCCs) and 2 were mesenchymal tumors (1 spindle cell tumor of probable neural origin, and 1 hemangiosarcoma). The GHs were noninvasive, exophytic, and did not recur after surgical excision. The SCCs were highly invasive tumors that induced facial deformation and were located in the caudal portion of the oral cavity, with 12 of them arising from the right-caudal maxilla. Thus, clinical signs, growth pattern, and anatomic location can be used to suspect a diagnosis of SCC among the other possible diagnoses, such as GH, in this location. However, histopathology is necessary for confirmation. Also, hemangiosarcoma should be considered among the differential diagnoses.

First report of fibropapillomatosis in an olive ridley turtle Lepidochelys olivacea from the southeastern Pacific.

An adult olive ridley turtle Lepidochelys olivacea with lesions suggestive of fibropapillomatosis was rescued on the coast of San Antonio, central Chile. Histopathologic analysis showed an exophytic and pedunculated mass formed by epidermal papillary projections supported by fibrovascular cores, epidermal hyperplasia and marked orthokeratotic hyperkeratosis. ChHV5 unique long genes UL27, UL28 and UL30 were amplified from tumor lesions and sequenced for phylogeny. Phylogenetic reconstruction showed the Chilean sequences clustering with the Eastern Pacific group. This is the first case of fibropapillomatosis in an olive ridley turtle diagnosed in Chile and in the southeastern Pacific region. Our results suggest a regional grouping of ChHV5 variants independent of the marine turtle's species.

Development of an orthotopic model of human metastatic prostate cancer in the NOD-SCIDγ mouse (Mus musculus) anterior prostate.

Prostate cancer is one of the most prevalent oncological diseases in males worldwide, and the mortalities resulting from this type of cancer are mainly due to metastasis. The most common models for the study of metastasis are transgenic and immunocompromised mice, which enable the study of the metastatic process in a controlled way by the injection of prostate cancer cells into the mice. In the present study, NOD-SCIDγ mice were injected orthotopically with PC3 cells in the anterior prostate in order to establish a metastatic model. The results demonstrated the development and growth of a primary tumor that preceded the formation of micrometastases in the lung, liver and pancreas, followed by macrometastases in the liver. This model adequately represents the dynamics of the metastatic process, and may be useful for novel therapeutic assays and post-surgical relapse studies.

Surgical cytoreduction of the primary tumor reduces metastatic progression in a mouse model of prostate cancer.

Metastatic prostate cancer (mPCa) is one of the most prevalent cancers in men worldwide. The main cause of death in these patients is androgen-resistant metastatic disease. Surgery of the primary tumor has been avoided in these patients as there is no strong evidence that supports a beneficial effect. From the biological point of view, it appears rational to hypothesize that the primary tumor may contribute to the establishment and growth of metastases. Considering this, we propose that cytoreductive surgery (CS) in advanced metastatic stage slows the progression of metastatic disease. To test this, we used a mouse model of resectable orthotopic prostate cancer (PCa) and performed CS. After surgery, metastases were smaller and less numerous in the treated mice; an effect that was observable until the end of the experiment. These results suggest that CS alone delays the progression of metastatic disease and that although this effect may be temporary, it may translate to prolonged survival, especially when used with adjuvant therapy.

Altered expression patterns of syndecan-1 and -2 predict biochemical recurrence in prostate cancer.

The clinical features of prostate cancer do not provide an accurate determination of patients undergoing biochemical relapse and are therefore not suitable as indicators of prognosis for recurrence. New molecular markers are needed for proper pre-treatment risk stratification of patients. Our aim was to assess the value of altered expression of syndecan-1 and -2 as a marker for predicting biochemical relapse in patients with clinically localized prostate cancer treated by radical prostatectomy. The expression of syndecan-1 and -2 was examined by immunohistochemical staining in a series of 60 paraffin-embedded tissue samples from patients with localized prostate cancer. Ten specimens from patients with benign prostatic hyperplasia were used as non-malignant controls. Semiquantitative analysis was performed to evaluate the staining patterns. To investigate the prognostic value, Kaplan-Meier survival curves were performed and compared by a log-rank test. In benign samples, syndecan-1 was expressed in basal and secretory epithelial cells with basolateral membrane localisation, whereas syndecan-2 was expressed preferentially in basal cells. In prostate cancer samples, the expression patterns of both syndecans shifted to granular-cytoplasmic localisation. Survival analysis showed a significant difference (P < 0.05) between normal and altered expression of syndecan-1 and -2 in free prostate-specific antigen recurrence survival curves. These data suggest that the expression of syndecan-1 and -2 can be used as a prognostic marker for patients with clinically localized prostate cancer, improving the prostate-specific antigen recurrence risk stratification.

The expression of syndecan-1 and -2 is associated with Gleason score and epithelial-mesenchymal transition markers, E-cadherin and beta-catenin, in prostate cancer.

The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where the invasive cancer cells change from epithelial to mesenchymal phenotype. During this process, a decrease or loss in adhesion molecules expression and an increase in migration molecules expression are observed. The aim of this work was to determine the expression and cellular distribution of syndecan-1 and -2 (migration molecules) and E-cadherin and beta-catenin (adhesion molecules) in different stages of prostate cancer progression. A quantitative immunohistochemical study of these molecules was carried out in tissue samples from benign prostatic hyperplasia and prostate carcinoma, with low and high Gleason score, obtained from biopsies archives of the Clinic Hospital of the University of Chile and Dipreca Hospital. Polyclonal specific antibodies and amplification system of estreptavidin-biotin peroxidase and diaminobenzidine were used. Syndecan-1 was uniformly expressed in basolateral membranes of normal epithelium, changing to a granular cytoplasmatic expression pattern in carcinomas. Syndecan-2 was observed mainly in a cytoplasmatic granular pattern, with high immunostaining intensity in areas of low Gleason score. E-cadherin was detected in basolateral membrane of normal epithelia showing decreased expression in high Gleason score samples. beta-Catenin was found in cell membranes of normal epithelia changing its distribution toward the nucleus and cytoplasm in carcinoma samples. We concluded that changes in expression and cell distribution of E-cadherin and beta-catenin correlated with the progression degree of prostate adenocarcinoma, suggesting a role of these molecules as markers of progression and prognosis. Furthermore, changes in the pattern expression of syndecan-1 and -2 indicate that both molecules may be involved in the EMT and tumor progression of prostate cancer.