Search Results

You are looking at 1 - 10 of 26 items for

  • Author or Editor: Arthur L. Craigmill x
  • Refine by Access: Content accessible to me x
Clear All Modify Search

Abstract

Objective—To compare the in vitro imMunosuppressive effects of cyclosporine and 4 novel immunosuppressive drugs on lymphocytes in whole blood collected from healthy cats.

Sample Population—Whole blood samples collected from 10 healthy adult domestic shorthair cats.

Procedure—Mitogen-stimulated lymphocyte proliferation in whole blood incubated with and without various concentrations of cyclosporine, tacrolimus, sirolimus, mycophenolic acid (MPA), or A771726 was measured by use of [3H]thymidine incorporation. Drug concentrations that resulted in a 50% inhibition of mitogen-induced proliferation (IC50) were calculated. Lymphocyte viability was determined by use of the trypan blue dye exclusion method.

Results—An obvious dose-response relationship for the antiproliferative effects of each drug was detected. Mean IC50 determined with concanavalin A was 46 nMfor cyclosporine, 9 nMfor tacrolimus, 12 nM for sirolimus, 16 nM for MPA, and 30 mM for A771726, whereas with pokeweed mitogen, mean IC50 was 33 nM for cyclosporine, 5 nMfor tacrolimus, 15 nM for sirolimus, 14 nM for mycophenolic acid, and 25 mM for A771726. Mitogen-stimulated and nonstimulated lymphocytes remained viable, regardless of drug evaluated.

Conclusions and Clinical Relevance—Tacrolimus, sirolimus, MPA, and A771726 inhibited in vitro mitogen- stimulated proliferation of feline lymphocytes in a dose-dependent manner. These novel immunosuppressive drugs may be useful for management of immune-mediated inflamMatory diseases and prevention and treatment of rejection in cats that undergo organ transplantation. (Am J Vet Res 2000;61: 906–909)

Full access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To develop a flow-limited, physiologicbased pharmacokinetic model for use in estimating concentrations of sulfamethazine after IV administration to swine.

Sample Population—4 published studies provided physiologic values for organ weights, blood flows, clearance, and tissue-to-blood partition coefficients, and 3 published studies provided data on plasma and other tissue compartments for model validation.

Procedure—For the parent compound, the model included compartments for blood, adipose, muscle, liver, and kidney tissue with an extra compartment representing the remaining carcass. Compartments for the N-acetyl metabolite included the liver and the remaining body. The model was created and optimized by use of computer software. Sensitivity analysis was completed to evaluate the importance of each constant on the whole model. The model was validated and used to estimate a withhold interval after an IV injection at a dose of 50 mg/kg. The withhold interval was compared to the interval estimated by the Food Animal Residue Avoidance Databank (FARAD).

Results—Specific tissue correlations for plasma, adipose, muscle, kidney, and liver tissue compartments were 0.93, 0.86, 0.99, 0.94, and 0.98, respectively. The model typically overpredicted concentrations at early time points but had excellent accuracy at later time points. The withhold interval estimated by use of the model was 120 hours, compared with 100 hours estimated by FARAD.

Conclusions and Clinical Relevance—Use of this model enabled accurate prediction of sulfamethazine pharmacokinetics in swine and has applications for food safety and prediction of drug residues in edible tissues. (Am J Vet Res 2005;66:1686–1693)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the antimicrobial susceptibility of common respiratory tract pathogens from sheep and goats.

Design—Cross-sectional study.

Sample Population—41 respiratory tract isolates from sheep and 36 isolates from goats.

Procedures—Disk diffusion assay was used to determine antimicrobial susceptibility of isolates to amoxicillin-clavulanic acid, ceftiofur, ciprofloxacin, florfenicol, and tetracycline. Minimum inhibitory concentrations of florfenicol for these isolates were determined by use of the microbroth dilution technique.

Results—The most common isolates were Pasteurella multocida (n = 28) and Mannheimia haemolytica (39). All isolates were susceptible to amoxicillin-clavulanic acid, ceftiofur, ciprofloxacin, and florfenicol. Five percent (4/77) of isolates were resistant to tetracycline.

Conclusions and Clinical Relevance—Susceptibility of respiratory tract pathogens isolated from sheep and goats to commonly used antimicrobial drugs in this study was high. Treatment of these species for bacterial respiratory tract disease is likely not complicated by antimicrobial resistance.

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association