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  • Author or Editor: Vivek Kapur x
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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).

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the in vitro sensitivity of 4 vaccine-associated feline sarcoma (VAFS) cell lines to the chemotherapeutic agents vincristine and paclitaxel.

Sample Population—Cell lines derived from 4 VAFS specimens.

Procedure—Cell lines were cultured in vitro and individually exposed to various concentrations of vincristine and paclitaxel. Survival was estimated after 24 and 72 hours of exposure to each drug, and the drug concentrations that resulted in 50 and 90% reduction in number of viable cells (IC50 and IC90, respectively) were calculated.

Results—Both vincristine and paclitaxel had significant dose-dependent effects on the viability of the VAFS cell lines. After 72 hours of drug exposure, the IC50 and IC90 of vincristine for the 4 cell lines were between 0.005 to 0.039 µg/ml and 0.045 to 1.027 µg/ml, respectively. The IC50 and IC90 values for paclitaxel were between 0.037 to 0.092 µg/ml and 2.450 to 15.413 µg/ml, respectively.

Conclusions—Results of pharmacokinetic studies on vincristine and paclitaxel in other species suggest that concentrations greater than the IC50 values may be possible for both drugs in feline patients as well. The drug concentrations at which viable cell numbers were reduced by 90% may also be attained in vivo for some cases, but detailed information is needed regarding the distribution, concentration, duration of availability, and toxicity of various drugs in cats. Carefully chosen combinations of antineoplastic agents need to be screened to identify treatment protocols that may be further evaluated clinically for the treatment of VAFS. (Am J Vet Res 2002;63:728–732)

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether repetitive sequence-based polymerase chain reaction (rep-PCR) could be used to differentiate Streptococcus equi isolates, to examine S equi isolates from throughout the world, and to determine whether a horse had > 1 subtype of S equi during an outbreak of disease.

Sample Population—An initial group of 32 S equi isolates, 63 S equi isolates from various geographic areas, and 17 S equi isolates obtained during outbreaks of disease.

Procedure—An aliquot of S equi genomic DNA was amplified, using enterobacterial repetitive intergenic consensus primers. Gel electrophoresis was performed on 1.5% agarose gels, and a computed-assisted program was used to compare rep-PCR results.

Results—Use of these primers to analyze 100 ng of S equi genomic DNA resulted in patterns of 6 to 14 bands. The 32 initial isolates were separated into 7 rep- PCR subtypes. There were 30 rep-PCR subtypes found among 29 S equi isolates obtained from Minnesota, Michigan, Canada, and Australia and 34 S equi isolates obtained from Kentucky and other sources. Furthermore, the same clone was identified in several horses during an outbreak of disease. Infected horses on the same farm all had a single clone of S equi.

Conclusion and Clinical Relevance—Analysis of these results suggests that rep-PCR is useful for delineating S equi into rep-PCR subtypes. Results revealed that isolates with the same geographic source or similar date of collection did not always have the same rep-PCR subtype. A single clone of S equi usually predominated during an outbreak of disease. (Am J Vet Res 2000;61:699–705)

Full access
in American Journal of Veterinary Research