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- Author or Editor: Laurel E. Williams x
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Abstract
Objective—To determine the association between lymph node size and metastasis and to assess measurement of lymph node size as an accurate and reliable means of tumor staging in dogs with oral malignant melanoma.
Design—Retrospective study.
Animals—100 dogs with histologically confirmed oral malignant melanoma.
Procedure—Clinical records for dogs with oral malignant melanoma were reviewed. Data regarding size and results of cytologic or histologic examination of lymph nodes were evaluated. The association between lymph node size and metastasis was determined.
Results—Forty-seven (47%) dogs, of which 23 (49%) had enlarged mandibular lymph nodes, had no cytologic or histologic evidence of metastasis. Of 53 (53%) dogs with cytologic or histologic evidence of mandibular lymph node metastasis, 37 (70%) had enlarged mandibular lymph nodes, and 16 (30%) had mandibular lymph nodes of normal size. Overall, 16 of the 40 (40%) dogs with normal-sized lymph nodes had microscopic evidence of metastatic disease. Sensitivity and specificity of lymph node size as a predictor of metastasis were 70 and 51%, respectively, and the positive and negative predictive values were 62 and 60%, respectively.
Conclusions and Clinical Relevance—Although a significant relationship was identified between lymph node size and metastasis to the lymph node, this association did not appear strong enough to be clinically relevant. Results suggest that lymph node size alone is insufficient for accurate clinical staging of oral malignant melanoma in dogs; cytologic or histologic examination of regional lymph nodes should routinely be performed, regardless of size of those nodes. (J Am Vet Med Assoc 2003;222:1234–1236)
Abstract
Objective—To evaluate the usefulness of a PCR-based telomeric repeat amplification protocol (TRAP) assay for detecting telomerase activity in cells from a canine transitional cell carcinoma (TCC) cell line and, ultimately, in the urine of dogs with TCC.
Animals—11 dogs with histologic or cytologic evidence of TCC, 10 dogs with benign lower urinary tract disease, and 9 healthy dogs.
Procedures—Telomerase activity was initially evaluated in cells from canine TCC (K9TCC) and telomerase-negative (WI-38) cell lines. Following assay optimization, telomerase stability was evaluated at various storage durations and temperatures. Urine samples were then obtained prospectively from study dogs.
Results—Telomerase activity was detected in the K9TCC cell line. The TRAP assay detected telomerase activity in as few as 10 K9TCC cells alone and as low as 2% of a total cell population in K9TCC and WI-38 mixing experiments. A loss of telomerase activity was detected with increasing urine storage durations at various temperatures. Telomerase activity was clearly detected in samples collected from 10 of 11 dogs with TCC, 2 of 10 dogs with benign lower urinary tract disease, and none of the 9 healthy dogs.
Conclusions and Clinical Relevance—The TRAP-based assay detected telomerase activity in the canine TCC cell line and revealed that the telomerase ribonucleoprotein complex was inherently unstable at various storage durations and conditions. Telomerase activity was also detectable in urine samples obtained from dogs with TCC, which suggested the TRAP assay may be useful in diagnosing TCC in dogs.
Abstract
Objective—To determine interclinician agreement when assessing remission of lymphoma in dogs and the association among results of clinicians' assessments via lymph node palpation, cytologic examination of fine-needle lymph node aspirates, and flow cytometry as determinants of remission.
Design—Prospective study.
Animals—23 dogs with untreated lymphoma.
Procedure—Two clinicians independently measured large lymph nodes and cytologic examination and flow cytometry of cells from a mandibular or popliteal lymph node were performed 1 week prior to initiating treatment. Lymph node measurements with clinicians' remission assessments and cytologic examination were repeated at weeks 2, 3, and 5; flow cytometry was repeated at week 5.
Results—Significant correlation was identified between clinicians' remission assessments. Significant correlation between lymph node palpation and cytologic examination was identified at week 5, but not at weeks 2 and 3. Lymphoma was diagnosed in 16 of 23 (70%) dogs at initial evaluation by use of flow cytometry, although it was of limited use at subsequent evaluations and results were not diagnostic of lymphoma in any dog at week 5, including 1 dog in which lymphoma was diagnosed cytologically.
Conclusions and Clinical Relevance—Results suggested that physical examination and measurement of lymph node volume may not be sufficient for accurately determining remission, that flow cytometry alone should not be relied on as a means for diagnosis, and that cytologic examination of fineneedle lymph node aspirates should be considered as the most accurate means of determining remission status at times in which treatment modifications are considered. (J Am Vet Med Assoc 2005;226:562–566)
Abstract
Objective—To establish 2 vaccine-associated feline sarcoma (VAFS) cell lines and to determine their in vitro sensitivity to the chemotherapeutic agents doxorubicin and mitoxantrone.
Sample Population—Tumor specimens collected from 2 cats undergoing surgery for removal of vaccine- associated sarcomas.
Procedures—Tumor specimens were minced and treated with trypsin under aseptic conditions to obtain single-cell suspensions, which were then cultured in vitro in medium supplemented with 5% heat-inactivated fetal bovine serum. Growth rates and sensitivity after 24 hours of exposure to various concentrations (0.1 to 100 μg/ml) of doxorubicin and mitoxantrone were assessed for each cell line. Survival of cells was estimated 3 days after exposure to the 2 agents, and the concentration of each drug that resulted in a 50% reduction in the number of viable cells (IC50) was calculated.
Results—Two tumor-derived cell lines (FSA and FSB) were successfully established and determined to be sensitive to doxorubicin and mitoxantrone. Under the conditions tested, the IC50 of doxorubicin were 0.6 and 1.5 μg/ml for cell lines FSB and FSA, respectively. The IC50 of mitoxantrone was 0.4 μg/ml for both cell lines.
Conclusions and Clinical Relevance—The establishment of VAFS cell lines provides a tool for the in vitro screening of antitumor drugs. Doxorubicin and mitoxantrone were effective in decreasing the number of viable cells in the 2 cell lines tested. Both of these anthracycline antibiotics have been used to treat various neoplasias in cats, and their efficacy for adjuvant treatment of vaccine-associated sarcomas should be further evaluated. (Am J Vet Res 2001;62:1354–1357).
Abstract
Objective—To determine clinical activity and toxic effects of lomustine when used to treat cats with mast cell tumors (MCTs).
Design—Retrospective case series.
Animals—38 cats with measurable, histologically or cytologically confirmed MCTs treated with lomustine at a dosage ≥ 50 mg/m2.
Procedures—Medical records were reviewed to determine response to treatment and evidence of drug toxicoses. The Kaplan-Meier method was used to estimate remission duration.
Results—26 cats had cutaneous MCTs, 7 had MCTs of the mesenteric lymph nodes, 2 had gastrointestinal tract MCTs, 2 had hepatic MCTs, and 1 had MCTs involving multiple organs. Targeted lomustine dosage was 50 mg/m2 in 22 cats and 60 mg/m2 in 16 cats. Median administered dosage of lomustine was 56 mg/m2 (range, 48 to 65 mg/m2), and median number of doses administered was 2 (range, 1 to 12). Seven cats had a complete response and 12 had a partial response, for an overall response rate of 50%. Median response duration was 168 days (range, 25 to 727 days). The most common toxicoses were neutropenia and thrombocytopenia.
Conclusions and Clinical Relevance—Results suggested that lomustine had activity against MCTs in cats and was well tolerated. Further, findings suggested that treatment with lomustine should be considered for cats with MCTs for which local treatment is not an option.
Abstract
Objective—To characterize the signalment, clinical signs, biological behavior, and response to treatment of carcinoma of the apocrine glands of the anal sac in dogs.
Design—Retrospective study.
Animals—113 dogs with histologically confirmed carcinoma of the apocrine glands of the anal sac.
Procedure—Data on signalment, clinical signs, and staging were reviewed and analyzed along with treatment modality for potential association with survival time.
Results—Sex distribution was approximately equal (54% female, 46% male). One hundred four dogs underwent treatment consisting of surgery, radiation therapy, chemotherapy, or multimodal treatment. Median survival for treated dogs was 544 days (range, 0 to 1,873 days). Dogs treated with chemotherapy alone had significantly shorter survival (median, 212 days) than those receiving other treatments (median, 584 days). Dogs not treated with surgery had significantly shorter survival (median, 402 days) than those that underwent surgery as part of their treatment (median, 548 days). Dogs with tumors ≥ 10 cm2 had significantly shorter survival (median, 292 days) than dogs with tumors ≥ 10 cm2 (median, 584 days). Hypercalcemia was identified in 27% (n = 29) of dogs, and those dogs had significantly shorter survival (median, 256 days), compared with those that were normocalcemic (median, 584 days). Dogs with pulmonary metastasis had significantly shorter survival (median, 219 days) than dogs without evidence of pulmonary metastasis (median, 548 days).
Conclusions and Clinical Relevance—Unlike most previous reports, this study revealed an approximately equal sex distribution, and results suggest a more favorable prognosis. (J Am Vet Med Assoc 2003;223: 825–831)
