The effects of Tarantula cubensis venom on open wound healing in rats.

OBJECTIVE: The aim of this study was to evaluate the clinical and histopathological effects of two different dosages of alcohol extract of Tarantula cubensis (Theranekron) on open wounds. METHOD: A total of 24 Sprague-Dawley rats were randomly divided into Tarantula cubensis extract (TCE1, n=8) 1/10 diluted, TCE (TCE2, n=8), and (3) vehicle-control (0.2 ml of 96 % ethanol, n=8) groups. Experimental full-thickness 1 x 1cm wounds were created on dorsum skin. TCE or vehicle were given systemically by subcutaneous injections on postoperative days 1 and 4. Wound planimetry and procurement of biopsies was performed on days 4, 8, 12 and 16. RESULTS: The mean non-epithelialised wound area in the vehicle-control group was significantly larger than in the TCE1 group on days 4, 8, 12 and 16, and in the TCE2 group on days 8, 12 and 16 (p<0.05). The mean percentage of wound contraction was significantly higher in the TCE1 and TCE2 groups than in the vehicle control group on days 8, 12 and 16 (p<0.05). Histopathologically, wound healing was characterised by a significant decrease in the neutrophil counts and a significant increase in neovascularisation; neither were effected by TCE. CONCLUSION: Our results suggest that alcohol extract of Tarantula cubensis accelerates epithelialisation and, thus, has beneficial effects on open wound healing in rats.

Valvular cardiac myxoma in a dog.

Primary and secondary cardiac tumours are extremely rare in humans and domestic animals. This case describes the gross, light microscopical and immunohistochemical examination of a cardiac myxoma arising from the tricuspid valve in a 13-year-old female terrier dog. Clinically, long-term respiratory distress, progressive ascites, fatigue and exercise intolerance were observed in the animal. At necropsy, the right ventricular chamber was mildly dilated and a soft, whitish mass, 0.7 x 1.5 x 2.1 cm in size was observed arising from the ventricular surface of the septal leaflet of the tricuspid valve of the heart. Histologically, the mass was composed of a faintly eosinophilic myxoid matrix and spindle shaped fibroblast-like cells with elongated nuclei and stellate cells. The extracellular matrix was stained with periodic acid Schiff and alcian blue and the tumour cells were reactive with anti-vimentin and anti-alpha-sarcomeric actin antibodies. The authors believe that this is the first detailed description of a myxoma in this breed.

Steroid receptor expression and HER-2/neu (c-erbB-2) oncoprotein in the uterus of cats with cystic endometrial hyperplasia-pyometra complex.

The presence of oestrogen-alpha receptor (ER), progesterone receptor (PR), and HER-2/neu (c-erbB-2) oncoprotein in the uterine walls of 10 healthy cats and 20 subjects with cystic endometrial hyperplasia-pyometra (CEH-P) were evaluated. Lesions were graded according to the severity of cystic dilation, hyperplasia and inflammation, and were classified as normal, mild uterine hyperplasia and severe uterine hyperplasia. The ER, PR and c-erbB-2 expression in the endometrium, glandular epithelium, stromal fibroblasts and myometrial smooth muscle cells was quantified by immunohistochemistry. The ER, PR and c-erbB-2 staining patterns differed between normal uteri and uteri with CEH-P. The ER expression was tended to be higher in the endometrial surface and glandular epithelium in the severe hyperplasia group (P > 0.05) and significantly lower in the mild hyperplasia cases compared with normal endometrium (P < 0.05), whereas the PR expression in both severe and mild hyperplasia cases tended to be higher in stromal cells and glandular epithelium than those in the normal uteri. C-erbB-2 immunoreactivity was observed only in the endometrial surface and glandular epithelium of the uterine wall and immunostaining was found to be highest in cases with severe hyperplasia. As a conclusion, we suggest that c-erbB-2 oncoprotein may play a role in the pathogenesis of the CEH together with the ER and PR in cats, and that ER does not have a role in the mechanism of pyometra, whereas PR plays a role in the pathogenesis of both CEH and pyometra.

A Clinico-pathological study on the effect of vincristine on transmissible venereal tumour in dogs.

Transmissible venereal tumour (TVT) is a coitally transmitted neoplasm of dogs and is common among sexually active dogs, where sexual behaviour is not under control. Several treatment options are available for the treatment of the tumour, with chemotherapy being the most commonly employed. In this study, we investigated the clinical and cytological changes after weekly vincristine sulphate administration in 38 cases of naturally occurring TVT. Tumours totally regressed in 31 dogs after two to seven doses (mean 3.54 +/- 1.01) of vincristine. One dog died after the fifth dose of vincristine, and in six dogs, an additional treatment with doxorubicin was needed. Masses were still present in four dogs and the histopathological examination revealed small nodules of granulation tissue in two dogs, while viable tumour cells were identified in the remaining two cases. No recurrences were observed in a follow-up period of 7-49 months (mean 13.64 +/- 9.66); in one dog, granulation tissue was detected in the surgery site after 2 months. Treatment success could easily be followed by the cytological changes. In conclusion, vincristine was found to be effective chemotherapeutic agent.

Clinico-pathological aspects of canine cutaneous and mucocutaneous plasmacytomas.

In this study the clinico-pathological aspects of cutaneous and mucocutaneous plasmacytomas were investigated in 63 dogs (one dog with two tumours). The tumours were most commonly observed in the skin of the trunk and legs. Yorkshire Terrier (n = 8) was the most commonly affected breed and males were affected more commonly than females (36 versus 23, respectively). Plasmacytomas were histologically classified into mature, hyaline, cleaved, asynchronous, monomorphous blastic and polymorphous blastic cell types. Monomorphous blastic cell type was the most frequent type (n = 21), followed by cleaved (n = 19) and asynchronous (n = 11) cell types. Secondary amyloid depositions were observed in eight cases. Immunohistochemical staining showed monoclonal lambda light chain positivity in all cases. In the immunohistochemical staining for cyclin D1, which is a prognostic marker in human plasma cell tumours, moderate numbers of positive tumour cells were observed in only one case of (muco)cutaneous plasmacytoma. All other cases were negative or contained few positive tumour cells. On the other hand, high numbers of tumorous plasma cells reacted positively with cyclin D1 in three out of six cases of canine multiple myelomas. Prognosis of the (muco)cutaneous plasmacytomas was good, except in one dog which developed a lymphoma afterwards. No significant correlations were observed between the cell type and the location of the tumour, presence of amyloid or prognosis.

Canine balloon and signet-ring cell melanomas: a histological and immunohistochemical characterization.

Seven tumours that were composed of balloon (n=4) or signet-ring (n=3) cells were investigated for a putative melanocytic origin. The tumours were located in the skin or the mouth cavity. In one case a sample from inguinal lymph node metastasis was available. Two antibodies used in man for the immunohistochemical diagnosis of melanomas, namely anti-Melan-A and anti-tyrosinase, were examined for their cross-reactivity with the corresponding canine antigens. The Melan-A antibody labelled all balloon cell tumours and one signet-ring cell tumour, whereas the anti-tyrosinase antibody was not reactive in any of the tumours. The Melan-A antibody also labelled a variety of canine epithelioid and spindle cell melanomas; non-melanocytic tumours were all negative. This study confirmed the occurrence of balloon and signet-ring cell melanomas in dogs. Melan-A antibody was found to be useful in the diagnosis of pigmented and non-pigmented canine melanomas.

Tyrosinase gene expression in clear cell sarcoma indicates a melanocytic origin: insight from the first reported canine case.

The aim of this study was to characterize a metastasizing soft tissue tumor in a dog, which clinically, grossly and histologically showed a close resemblance to human clear cell sarcoma, a soft tissue variant of malignant melanoma. Ultrastructurally, melanosomes were found, indicating a melanocytic origin of the tumor. Using reverse-transcription polymerase chain reaction, expression of the gene encoding tyrosinase was determined in tumor cells. With this first case of canine clear cell sarcoma, as well as the earlier report from our laboratory on amelanotic melanomas in the cat, we demonstrate that expression of the tyrosinase gene may occur in a broader range of less differentiated melanocytic tumors in different species, including man.