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Abstract

OBJECTIVE

To quantify acute immunologic and metabolic responses of beef heifers following topical administration of transdermal flunixin meglumine (TDFM) at various times relative to bovine herpesvirus 1 (BHV1) and Mannheimia haemolytica challenges.

ANIMALS

32 beef heifers (mean body weight, 170 kg).

PROCEDURES

Heifers were assigned to 1 of 4 groups. Heifers in the control group did not receive TDFM, whereas 1 dose of TDFM (3.3 mg/kg) was topically applied to heifers of groups A, V, and B at −144, −72, and 0 hours. All heifers were inoculated with 1 × 108 plaque-forming units of BHV1 in each nostril at −72 hours and with 1.18 × 106 CFUs of M haemolytica intratracheally at 0 hours. Vaginal temperature was recorded and blood samples were collected for quantification of select immunologic and metabolic biomarkers at predetermined times from −144 to 360 hours.

RESULTS

Mean vaginal temperature was similar between group A and the control group. Mean vaginal temperatures for groups V and B were generally lower than that for the control group following BHV1 and M haemolytica challenges, respectively. Mean neutrophil oxidative burst capacity and L-selectin expression at 0 hours were significantly decreased for group V relative to the other groups. Other biomarkers did not differ among the groups at any time.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that topical administration of TDFM to beef cattle effectively alleviated pyrexia without adverse effects on acute immunologic or metabolic responses when TDFM was administered at the same time as, but not before, respiratory pathogen challenge.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the prevalence of antibodies against a swine-origin Helicobacter pylori–like organism (HPLO) and H pylori in conventionally reared swine.

Animals—640 conventionally reared swine of various ages from 16 high-health farms in Canada, 20 sows from Ohio, and 35 gnotobiotic swine.

Procedures—Blood was collected from the cranial vena cava. Sera were collected and tested via ELISA for antibodies against antigen prepared from a swine-origin HPLO and human H pylori strain 26695.

Results—Antibodies reactive with a swine HPLO, H pylori, or both were detected in 483 of 640 swine from all 16 farms in western Canada. Seroprevalence varied with age and was low (5.6%) in suckling (≤ 4-week-old) swine and increasingly high in swine ranging from > 4 weeks old to adulthood.

Conclusions and Clinical Relevance—Findings suggested that colonization by a swine-origin HPLO, H pylori, or both and resultant seroconversion, like that of H pylori infection in humans, were common in commercial swine operations. Furthermore, data indicated that gastric infection was acquired at an early age. The relationships to gastric colonization by HPLOs and clinical manifestations of disease such as gastritis and gastroesophageal ulceration remain to be determined.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether feline vaccine siteassociated sarcomas (VSS) contain a higher amount of endogenous FeLV (enFeLV) RNA, compared with feline nonvaccine site-associated sarcomas (non-VSS).

Sample Population—Formalin-fixed paraffin-embedded (FFPE) tissues from 50 VSS and 50 cutaneous non-VSS.

Procedure—RNA was extracted from FFPE sections of each tumor, and regions of the long terminal repeat (LTR) and envelope (env) gene of enFeLV were amplified by use of reverse transcriptase-polymerase chain reaction (RT-PCR). The density of each RT-PCR product band for enFeLV was compared with that of a constitutively expressed gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH). An integrated density value (IDV) was determined by use of densitometry, and the IDV ratio for enFeLV to GAPDH was calculated for each enFeLV primer set.

Results—The median (interquartile range) of the IDV ratio for the enFeLV LTR primer set was 0.52 (0.26 to 1.17) for the VSS group and 0.84 (0.21 to 1.53) for the non-VSS group. The median (interquartile range) of the IDV ratio for the enFeLV env primer set was 0.60 (0.37 to 0.91) for the VSS group and 0.59 (0.36 to 1.09) for the non-VSS group.

Conclusions—Because the amount of enFeLV RNA within the LTR and env gene was not significantly different between the VSS and non-VSS groups, enFeLV replication or expression is unlikely to be involved in VSS development. (Am J Vet Res 2001;62:1990–1994)

Full access
in American Journal of Veterinary Research

Summary

A simple cryogenic technique for preserving bovine buffy coat leukocytes was developed. This was coupled with a variation of the standard discontinuous gradient technique to purify mononuclear cells that retained immunologic function. The total number of mononuclear cells recovered from cyropreserved samples were only 87 to 42% of those recovered from freshly obtained blood samples. However, the functional capabilities of mononuclear cells from cyopreserved buffy coat preparations were retained. Polyclonal proliferative responses to 3 mitogens were measured, using a titration of mitogen concentrations, and were found to be normal, compared with those of cells isolated from fresh blood. Blood samples collected after vaccination with Brucella abortus contained leukocytes that responded to irradiated B abortus. These antigen-specific responses were also retained through cyopreservation. Cell surface expression of T-lymphocyte antigens, CD2, CD4, and CD8, and cell-surface IgM on B lymphocytes was also evaluated. Flow cytometric analysis of fresh and cryopreserved mononuclear cell preparations indicated that the relative proportions of different subpopulations were not altered. The technical simplicity of our cryopreservation system will allow processing of large numbers of samples with the ability to assay various immune functions at a later time.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether genogroup 1 porcine torque teno virus (g1-TTV) can potentiate clinical disease associated with porcine circovirus type 2 (PCV2).

Sample population—33 gnotobiotic baby pigs.

Procedures—Pigs were allocated into 7 groups: group A, 5 uninoculated control pigs from 3 litters; group B, 4 pigs oronasally inoculated with PCV2 alone; group C, 4 pigs inoculated IP with first-passage g1-TTV alone; group D, 4 pigs inoculated IP with fourth-passage g1-TTV alone; group E, 6 pigs inoculated IP with first-passage g1-TTV and then oronasally inoculated with PCV2 7 days later; group F, 6 pigs inoculated IP with fourth-passage g1-TTV and then inoculated oronasally with PCV2 7 days later; and group G, 4 pigs inoculated oro-nasally with PCV2 and then inoculated IP with fourth-passage g1-TTV 7 days later.

Results—6 of 12 pigs inoculated with g1-TTV prior to PCV2 developed acute onset of postweaning multisystemic wasting syndrome (PMWS). None of the pigs inoculated with g1-TTV alone or PCV2 alone or that were challenge exposed to g1-TTV after establishment of infection with PCV2 developed clinical illness. Uninoculated control pigs remained healthy.

Conclusions and Clinical Relevance—These data implicated g1-TTV as another viral infection that facilitates PCV2-induced PMWS. This raises the possibility that torque teno viruses in swine may contribute to disease expression currently associated with only a single infectious agent.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether immunity against bovine respiratory syncytial virus (BRSV) mitigates the effects of 3-methylindole (3MI) on occurrence of bovine respiratory tract disease (BRD) and rate of gain in feedlot cattle.

Animals—254 mixed-breed beef cattle.

Procedure—Cattle were randomly assigned to 1 of 3 groups at the time of arrival at the feedlot. One group was vaccinated with an inactivated BRSV vaccine, another was vaccinated with a modified-live BRSV vaccine, and the third was maintained as unvaccinated control cattle. On days 0 and 28, serum BRSV antibody concentrations were measured, using serum neutralizing and ELISA techniques. Serum 3MI concentrations were measured at feedlot arrival and 3 days later. Cattle were monitored for development of BRD. At slaughter, lungs were evaluated grossly for chronic lesions.

Results—Higher serum 3MI concentrations early in the feeding period were associated with lower mean daily gain. Control cattle were more likely to be treated for BRD after day 3, compared with cattle vaccinated with the modified-live BRSV vaccine. Humoral immunity against BRSV did not appear to modify the effect of 3MI on development of BRD or mean daily gain.

Conclusions and Clinical Relevance—Results suggest that abrogating the effects of 3MI and BRSV infection may improve the health and growth performance of feedlot cattle. However, in this study, immunity against BRSV did not appear to protect against the potential synergism between 3MI and BRSV infection, possibly because of the slow rates of gain of cattle included in the study or timing of sample collection. (Am J Vet Res 2000;61:1309–1314)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate a group of vaccine site-associated sarcomas (VSS) for the presence of feline foamy virus (FeFV) DNA, using polymerase chain reaction (PCR) methods.

Sample Population—50 formalin-fixed paraffin embedded (FFPE) tissue blocks from VSS of cats.

Procedure—DNA was extracted from FFPE sections of each tumor, and regions of the gag and pol genes of FeFV were amplified by use of PCR methods, using 1 primer set for each region. Sensitivity of the method was compared between fresh and FFPE cells, using mouse kidney tissue that was injected with FeFVinfected cultured cells and using agarose-cell pellets.

Results—Feline foamy virus DNA was not detected in VSS tissues. Sensitivity of the method was 10 times greater in fresh versus FFPE mouse tissues. Sensitivity of the method in fresh FeFV-infected cultured cells versus FFPE agarose-cell pellets was equal when fixation was 24 or 48 hours and 10 times greater when fixation was 72 hours or 1 week.

Conclusion and Clinical Relevance—A PCR-based method can be successfully applied to FFPE tissues for FeFV DNA detection. Results suggest there is no direct FeFV involvement in the pathogenesis of VSS in cats. (Am J Vet Res 2002;63:60–63)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether vaccine site-associated sarcomas (VSS) from cats contain papillomavirus antigen or DNA.

Sample Population—50 formalin-fixed paraffinembedded tissue blocks of VSS from cats.

Procedure—Sections from each tissue block were evaluated for papillomavirus antigen by use of an avidin-biotin-complex immunohistochemical staining method, using rabbit anti-bovine papillomavirus type-1 antibody. The DNA was extracted from sections of each tissue block, and polymerase chain reaction assays were performed, using primers designed to amplify regions of the E5 gene of bovine papillomavirus and consensus primers designed to amplify a region of the L1 gene of animal papillomaviruses. Sections from 20 of the tissue blocks were evaluated by use of nonradioactive in situ hybridization for bovine papillomavirus DNA.

Results—Papillomavirus antigen and DNA were not detected in any of the VSS.

Conclusions and Clinical Relevance—Results suggest that papillomaviruses likely do not have any direct involvement in the pathogenesis of VSS in cats. (Am J Vet Res 2001;62:833–839)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether vaccine site-associated sarcomas (VSS) from cats contain polyomavirus antigen or DNA.

Sample Population—50 formalin-fixed paraffinembedded tissue blocks of VSS from cats.

Procedure—Sections from each tissue block were evaluated for polyomavirus antigen by use of an avidin-biotin-complex immunohistochemical staining method, using rabbit anti-murine polyomavirus polyclonal antiserum as the primary antibody. The DNA was extracted from sections of each tissue block, and a polymerase chain reaction assay was performed, using primers designed to amplify regions of the bovine polyomavirus genome and consensus polyomavirus primers designed to detect unknown polyomaviruses.

Results—Polyomavirus antigen and DNA were not detected in any of the VSS.

Conclusions and Clinical Relevance—Results suggest that polyomaviruses likely do not have any direct involvement in the pathogenesis of VSS in cats. (Am J Vet Res 2001;62:828–832)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the use of a polymerase chain reaction (PCR) method for detection of feline immunodeficiency virus (FIV) DNA, using formalin-fixed paraffin- embedded (FFPE) tissues, and to use this method to evaluate tissues obtained from vaccine site-associated sarcomas (VSS) of cats for FIV DNA.

Sample Population—50 FFPE tissue blocks from VSS of cats and 50 FFPE tissue blocks from cutaneous non-vaccine site-associated fibrosarcomas (non-VSS) of cats.

Procedure—DNA was extracted from FFPE sections of each tumor and regions of the gag gene of FIV were amplified by a PCR, using 3 sets of primers. Sensitivity of the method was compared between frozen and FFPE tissues, using splenic tissue obtained from a cat that had been experimentally infected with FIV.

Results—We did not detect FIV DNA in VSS or non- VSS tissues. Sensitivity of the PCR method was identical for frozen or FFPE tissues.

Conclusions and Clinical Relevance—It is possible to detect FIV DNA in FFPE tissues by use of a PCR. We did not find evidence to support direct FIV involvement in the pathogenesis of VSS in cats. (Am J Vet Res 2000;61:1037–1041)

Full access
in American Journal of Veterinary Research