Clinical assessment of a chemosensitivity assay as a treatment planning tool for dogs with cancer.

This study evaluated the clinical utility of a commercially available chemosensitivity assay. In the first part of the study, tumor tissues from dogs with various malignancies were tested, and the dogs were treated with a mitoxantrone/cyclophosphamide combination protocol. Tumor response was evaluated and compared to the predicted response. Assay results were not a significant predictor of clinical response to chemotherapy or of survival time. In the second part of the study, assay results were used to direct therapy in dogs with refractory lymphoma. There was no significant correlation (p equals 0.323) between predicted response and case outcome.

Mitoxantrone and cyclophosphamide combination chemotherapy for the treatment of various canine malignancies.

Thirteen dogs with histopathologically confirmed malignancies were treated with mitoxantrone and cyclophosphamide combination therapy. One to four doses were administered at 21-day intervals. Recombinant human granulocyte colony-stimulating factor was administered to ameliorate myelosuppression in dogs with neutrophil nadirs less than 1,000/microl. While the protocol appears to be safe for use in tumor-bearing dogs, an advantage over mitoxantrone single-agent protocols in terms of tumor response was not demonstrated in this initial pilot study.

Systemic and tissue chamber fluid platinum concentrations released from cis-diamminedichloroplatinum II-impregnated polymethylmethacrylate in healthy dogs.

OBJECTIVES: To determine systemic and local platinum concentrations released from subcutaneously implanted cis-diamminedichloroplatinum (cisplatin) -impregnated polymethylmethacrylate (PMMA) and to evaluate systemic or local adverse reactions. ANIMALS: 6 healthy dogs. PROCEDURE: Cisplatin (20 mg) was inserted into PMMA that was fashioned into cylinders and placed into subcutaneous tissue chambers overlying the thorax (treated site). An empty tissue chamber was placed over the opposite side (control site). Plasma samples were obtained for platinum determination before implantation, at 3, 6, and 12 hours after implantation on day 0, and once daily on days 1, 2, 3, 7, 14, 21, and 29. At similar times on similar days, tissue chamber fluid samples also were obtained for platinum determination. Complete blood count, serum urea nitrogen and creatinine concentration determinations, and urinalyses were performed on days 1, 2, 3, 7, 14, 21, and 29. Complete necropsy was performed at conclusion of the study. RESULTS: Tissue chamber platinum concentrations at the treated site were significantly greater than plasma and control site tissue chamber concentrations on days 2, 3, 7, 10. Mean plasma platinum concentration at 3 (0.735 microg/ml), 6 (0.691 microg/ml), 12 (0.534 microg/ml), 24 (0.131 microg/ml), 48 (0.2 microg/ml), 72 (0.1 microg/ml), and 158 (0.014 microg/ml) hours was significantly greater than pretreatment values (0.0 microg/ml). Plasma platinum concentration 10 days after treatment (0.011 microg/ml) did not significantly differ from pretreatment values. Local or systemic adverse reactions were not apparent. CONCLUSIONS: The route of cisplatin administration was safe. Greater concentration of platinum was released locally relative to plasma concentration for an extended period.

Gastroesophageal intussusception in a Labrador retriever.

A 14-month-old, intact male Labrador retriever was referred for evaluation of vomiting and regurgitation. A diagnosis of gastroesophageal intussusception with aspiration pneumonia was made. The patient responded favorably to aggressive surgical and medical management. The guarded to poor prognosis for gastroesophageal intussusception makes the successful outcome of this case unique.

Cutaneous mast cell tumors in cats: 32 cases (1991-1994).

Case records of 32 cats with cutaneous mast cell tumors (CMCTs) were reviewed. Using the Patnaik system for grading canine mast cell tumors, the relationships between histopathological grade and patient survival time and tumor recurrence were examined. Tumor histopathological grade had no prognostic significance. One-, two-, and three-year tumor recurrence rates following surgical excision were 16%, 19%, and 13%, respectively. Incomplete excision was not associated with a higher rate of tumor recurrence.

Gingival vascular hamartoma with associated paraneoplastic hyperglycemia in a kitten.

A 4-month-old domestic shorthair cat was examined because of a maxillary gingival mass that had regrown following excisional biopsy. The kitten also had a history of persistently high blood glucose concentrations, despite 2 weeks of insulin treatment. Radiography revealed maxillary alveolar bone lysis and displacement of multiple teeth. Partial maxillectomy was performed to remove the mass, which histologically was a gingival vascular hamartoma. Hyperglycemia permanently resolved < 24 hours after mass removal. On the basis of the temporal relationship between mass removal and resolution of hyperglycemia, as well as the lack of evidence of any concurrent disease, hyperglycemia in this cat was considered to be a paraneoplastic syndrome.

Accuracy of microchip identification in dogs and cats.

A study was performed to determine the sensitivity and specificity of a commercially available microchip identification system approximately 1 year after implantation in dogs and cats. Thirty-three dogs and 16 cats in which a microchip had been implanted and 31 dogs and 18 cats in which a microchip had never been implanted were included in the study. In cats, sensitivity and specificity of microchip identification were 1.00. In dogs, sensitivity and specificity were 0.97 and 1.00, respectively. The chip had migrated in the 1 dog with a false-negative result, but the chip remained functional, and identification was established in this dog following closer physical examination and scanning.