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  • Author or Editor: Cheryl L. Swenson x
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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether infectious retrovirus was inactivated in bones from FeLV-infected cats after ethylene oxide (ETO) sterilization or preservation in a 98% solution of glycerol in an in vitro cell culture system.

Sample Population—Metatarsal bones obtained from 5 FeLV-infected cats and cultured with feline fibroblast cells.

Procedure—Metatarsal bones were treated with 100% ETO, a 98% solution of glycerol, or left untreated. Twenty-five flasks of feline fibroblast cells were assigned to 5 groups: negative control, positive control, ETO-treated bone, glycerol-treated bone, and untreated bone with 5 replicates/group for 4 passages. Media and cell samples were harvested from every flask at each passage to measure FeLV p27 antigen and the number of copies of provirus per 100 ng of DNA, respectively.

Results—All negative control and ETO-treated group replicates were negative for FeLV p27 antigen and provirus throughout the study. All positive control group replicates were positive for FeLV p27 antigen and provirus at passages 1 to 4. Untreated bone group replicates were positive for FeLV p27 antigen at passages 3 and 4 and provirus beginning at passage 2. Glycerol-treated group replicates had delayed cell replication and were negative for FeLV p27 antigen and provirus at passages 1 to 4 and 2 to 4, respectively.

Conclusions and Clinical Relevance—Ethylene oxide sterilization of bone from FeLV-infected cats appeared to abrogate transmission of infectious retrovirus and effectively sterilized bone allografts.

Impact for Human Medicine—Additional studies to confirm effectiveness of ETO treatment of allograft tissues for prevention of pathogen transmission via transplantation are warranted. (Am J Vet Res 2004;65:436–439)

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in American Journal of Veterinary Research

Abstract

Objective—To determine the effect of bovine leukemia virus (BLV) infection on absolute neutrophil and lymphocyte concentrations in healthy lactating Holstein dairy cattle.

Design—Observational cross-sectional survey.

Animals—311 healthy lactating Holstein dairy cattle from herds in Michigan (n = 2), Wisconsin (1), Iowa (1), and Pennsylvania (1).

Procedures—Whole and anticoagulated (EDTA) blood samples were collected. Serum samples were tested for antibody against BLV by use of an ELISA. Absolute neutrophil and lymphocyte concentrations were measured in EDTA blood samples with an automated hematology analyzer and manual differential cell counts.

Results—208 cows tested positive and 103 cows tested negative for anti-BLV antibodies. Neutrophil concentration was not significantly different between BLV-positive versus BLV-negative cattle. The distribution of lymphocyte concentration was positively skewed for the entire cow population (n = 311) and the BLV-positive subset (208). In contrast, lymphocyte concentration distribution was approximately normal for BLV-negative cows (n = 103). Consequently, the presence or absence of BLV infection strongly influenced the calculated neutrophil-to-lymphocyte concentration ratio.

Conclusions and Clinical Relevance—Results indicated that absolute lymphocyte concentration is significantly affected by BLV infection in dairy cattle. Accordingly, hematologic reference intervals should be derived from healthy animals that are not infected with BLV and patient BLV status must be considered for meaningful interpretation of lymphocyte concentration. We recommend that the calculated neutrophil-to-lymphocyte ratio be abandoned because it does not provide more information than direct comparison of patient absolute leukocyte concentration with updated reference intervals from healthy BLV-negative cattle.

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in Journal of the American Veterinary Medical Association

  • Recognition of the diverse shapes of various urine crystals is necessary for their accurate identification.

  • Calcium oxalate dihydrate crystals most commonly have an octahedral or envelope shape.

  • Calcium ions and oxalic acid may form calcium oxalate crystals in urine.

  • Calcium oxalate dihydrate crystalluria is a risk factor for urolith formation.

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in Journal of the American Veterinary Medical Association

Abstract

Objectives—To compare virucidal effects and bone incorporation properties of cortical bone allografts transplanted into specific-pathogen-free (SPF) cats. Allografts consisted of untreated bone from a SPF cat (negative-control group) and bone from 5 FeLV-infected cats that was subjected to sterilization with ethylene oxide (ETO), preservation with glycerol, or no treatment (positive-control group).

Sample Population—Bones from the aforementioned groups and twenty 8-week-old SPF cats (5 cats/group) implanted with an allograft from 1 of the aforementioned groups.

Procedure—After implantation, blood samples were collected weekly to monitor FeLV p27 antigen and antibody titers. Quantification of FeLV provirus was performed on blood samples at weeks 0, 4, and 8 and donor bone samples at time of implantation. Cats were euthanatized 8 weeks after transplantation, and graft sites were evaluated.

Results—All results for negative-control cats were negative. All ETO group cats had negative results for antigen and provirus in blood, whereas 1 cat had a low antibody titer. Although 3 ETO-treated allografts were positive for provirus, the DNA appeared denatured. One cat in the glycerol group had positive results for all tests in blood samples. All glycerol-preserved allografts were positive when tested for provirus. All results for positive-control group cats were positive. Differences in incorporation of bone grafts were not observed.

Conclusions and Clinical Relevance—Glycerol preservation of FeLV-infected bone allografts did not eliminate transmission of retrovirus to recipients. In contrast, ETO sterilization appeared to denature DNA and prevent infection. Treatments did not affect incorporation of bone grafts in young cats. (Am J Vet Res 2000;61:665–671)

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

Abstract

Objective—To compare the findings of light microscopic evaluation of routine unstained wet-mounted preparations and air-dried, modified Wright-stained preparations of urine sediment with results of quantitative aerobic bacteriologic culture of urine.

Design—Masked prospective study.

Sample Population—459 urine samples collected by cystocentesis from 441 dogs.

Procedure—Urinalyses and quantitative bacteriologic cultures of urine were performed. Unstained wetmounted preparations and air-dried, modified Wrightstained urine sediment preparations were examined by light microscopy for the presence of bacteria.

Results—Compared with results of quantitative bacteriologic culture, routine unstained preparations and modified Wright-stained preparations had sensitivities of 82.4% and 93.2%, specificities of 76.4% and 99.0%, positive predictive values of 40.1% and 94.5%, negative predictive values of 95.8% and 98.7%, and test efficiencies of 77.3% and 98.0%, respectively. Compared with 74 samples that yielded growth on bacteriologic culture, the routine unstained method had concordance and misclassification rates of 39.2% and 60.8%, respectively, whereas the Wright-stained method had concordance and misclassification rates of 78.4% and 21.6%, respectively. Significant associations between each of occult blood in urine, pyuria, female sex, and lower urine specific gravity with bacteriuria detected by Wright-stained sediment examination and quantitative bacteriologic culture of urine were identified.

Conclusions and Clinical Relevance—Examination of modified Wright-stained preparations of urine sediment appeared to be a rapid, cost effective method that significantly improved the sensitivity, specificity, positive predictive value, and test efficiency of light microscopic detection of bacteriuria, compared with that of the routine unstained method. (J Am Vet Med Assoc 2004; 224:1282–1289)

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

SUMMARY

Phosphonoformate (pfa), a noncompetitive inhibitor of reverse transcriptase (rt), inhibited feline leukemia virus (FeLV) infection of 2 feline cell lines and inhibited progeny virus rt activity in a chronically FeLV-infected cell line. Feline leukemia virus infection of 3201 cells, an FeLV-negative lymphoma cell line, was inhibited by > 70% at a concentration of only 1 μM pfa and by > 90% at concentrations of 64 to 256 μM pfa, as evidenced by rt activity. However, FeLV antigen expression by 3201 cells remained relatively constant over noncytotoxic concentrations of pfa. Because the persistence of viral antigen expression with concomitant suppression of rt activity appears to be unique and because 3201 cells express small amounts of an endogenous retrovirus (RD-114) and contain endogenous FeLV proviral sequences, a possible role of endogenous retroviruses acting as helper viruses was suggested. Feline leukemia virus infection of 81C cells, a sarcoma-positive, leukemia-negative fibroblast cell line, was inhibited by > 50% at a concentration of 64 μM pfa and by > 98% at concentrations of 256 to 512 μM pfa, as indicated by suppression of focus formation. The feline lymphoid cell line FL-74 is a large producer of FeLV. When FL-74 cells were cultured in the presence of 256 μM pfa, virus production (virus budding and viral antigen) was not affected, but progeny virus lost rt activity and infectivity. Direct addition of pfa (256 μM) to FeLV also reduced rt activity and infectivity. These data indicate that pfa can directly and rapidly inactivate retrovirus independent of cellular processing, presumably by inhibiting rt. Long-term pfa administration may curtail spread of retroviral infections within and between hosts via extracellular inactivation of newly produced virus particles. Results of this study also suggest that pfa might be used prophylactically to treat materials potentially contaminated with retroviruses.

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in American Journal of Veterinary Research