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  • Author or Editor: Deborah M. Haines x
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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

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)

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in American Journal of Veterinary Research

Abstract

Objective—To describe 3 epidemics of respiratory tract disease caused by influenza virus infections in a large population of horses.

Design—Cross-sectional and prospective longitudinal observational studies.

Animals—All horses stabled at a Thoroughbred racetrack.

Procedure—During a 3-year period, descriptive information was collected as horses arrived at the racetrack and throughout race meetings. Routine observations and physical examinations were used to classify horses' disease status. Cause of epidemics was established by use of serologic testing and identification of influenza virus in nasal secretions.

Results—An epidemic of respiratory tract disease caused by influenza virus infections was identified during each year of the study. Attack rates of infectious upper respiratory tract disease (IURD) ranged from 16 to 28%. Incidence of disease caused by influenza virus infections during racing seasons in the second and third years was 27 and 37 cases/1,000 horses/mo, respectively. Physical distributions of stall locations revealed that affected horses were stabled throughout the population; horses affected later in epidemics were often clustered around horses affected earlier. Mucopurulent nasal discharge and coughing were observed in 83 and 62% of horses with IURD, respectively. Median duration of clinical disease was 11 days. Serologic testing was the most sensitive method used to detect influenza virus infections; 76% of affected horses seroconverted to influenza virus.

Conclusion and Clinical Relevance—Epidemics of IURD were observed annually in association with influenza virus infections. Few precautions were taken to limit spread of infection. Preventing or decreasing the likelihood of exposure and improving immunity in the population could substantially decrease risk of disease in similar populations. (J Am Vet Med Assoc 2000;216:535–544)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify risk factors associated with respiratory tract disease in horses during 3 epidemics caused by influenza virus infections.

Design—Cross-sectional and prospective longitudinal observational studies.

Animals—1,163 horses stabled at a Thoroughbred racetrack.

Procedure—Investigations were conducted during a 3-year period. An epidemic of respiratory tract disease caused by influenza virus infections was identified in each year. Routine observations and physical examinations were used to classify horses' disease status. Data were analyzed to identify factors associated with development of disease.

Results—Results were quite similar among the epidemics. Concentrations of serum antibodies against influenza virus and age were strongly associated with risk of disease; young horses and those with low antibody concentrations had the highest risk of disease. Calculation of population attributable fractions suggested that respiratory tract disease would have been prevented in 25% of affected horses if all horses had high serum antibody concentrations prior to exposure. However, recent history of vaccination was not associated with reduction in disease risk. Exercise ponies had greater risk of disease than racehorses, which was likely attributable to frequent horse-to-horse contact.

Conclusion and Clinical Relevance—Particular attention should be paid to young horses, those with low serum antibody concentrations, and horses that have frequent contact with other horses when designing and implementing control programs for respiratory tract disease caused by influenza virus infections. It appears that control programs should not rely on the efficacy of commercial vaccines to substantially reduce the risk of disease caused by influenza virus infections. (J Am Vet Med Assoc 2000;216:545–550)

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in Journal of the American Veterinary Medical Association

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 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

Objectives—To investigate the role of tumor suppressor gene p53 mutation in feline vaccine site-associated sarcoma (VSS) development and to evaluate the relationship between p53 nucleotide sequence and protein expression.

Sample Population—Formalin-fixed paraffinembedded tissues of 8 feline VSS with dark p53 immunostaining (high p53 expression) and 13 feline VSS with faint or no staining (normal p53 expression).

Procedure—DNA was extracted from neoplastic and normal tissue from each paraffin block. The following 3 regions of the p53 gene were amplified by polymerase chain reaction: 379 base pair (bp) region of exon 5, intron 5, and exon 6, 108 bp region of exon 7, and 140 bp region of exon 8. Amplified p53 products were sequenced and compared with published feline p53. The p53 mutations identified were correlated with p53 mutations predicted by immunostaining.

Results—Neoplastic cells of 5 of 8 (62.5%) VSS that had high p53 expression harbored single missense mutations within the p53 gene regions examined. The p53 gene mutations were not detected in the 13 tumors with normal p53 immunostaining. Nonneoplastic tissues adjacent to all 21 VSS lacked mutations of these p53 gene regions.

Conclusions—The p53 gene mutations were restricted to neoplastic tissue and, therefore, were unlikely to predispose to VSS. However, p53 mutations may have contributed to cancer progression in 5 of the 21 VSS. There was very good (κ quotient = 0.67 with a confidence limit of 0.3 to 1.0), although not complete, agreement between prediction of mutation by p53 immunostaining and identification of mutations by sequencing of key p53 gene regions. (Am J Vet Res 2000;61:1277–1281)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare the efficacy of a lacteal-derived colostrum replacer (LDCR) for the prevention of failure of passive transfer of immunity (FPT) in calves with that of pooled maternal colostrum (MC).

Design—Randomized field trial.

Animals—568 heifer calves from 1 California dairy.

Procedures—Calves were randomly allocated to 1 of 2 treatment groups and fed 2 doses (200 g of IgG) of an LDCR or 3.8 L of pooled MC. From each calf, blood samples were collected before and approximately 24 hours after treatment. Serum IgG and total protein (TP) concentrations were quantified with standard methods, and the apparent efficiency of IgG absorption was calculated.

Results—At 24 hours after treatment, mean serum TP and IgG concentrations were significantly lower for calves fed pooled MC (TP, 4.77 g/dL; IgG, 7.50 g/L), compared with those for calves fed the LDCR (TP, 5.50 g/dL; IgG, 15.15 g/L). Calves fed the LDCR were 95% less likely to develop FPT (OR, 0.05; 95% confidence interval, 0.03 to 0.08) than were calves fed pooled MC. However, the mean IgG concentration in the pooled MC fed during the study (21.1 g/L) was substantially lower than that (64.3 g/L) determined for representative samples of pooled MC from other southwestern US dairies during a national survey.

Conclusions and Clinical Relevance—Results indicated that, on this particular dairy, calves fed an LDCR were at less risk of developing FPT than were calves fed pooled MC. The LDCR evaluated was a viable alternative for the prevention of FPT in calves.

Restricted access
in Journal of the American Veterinary Medical Association

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 comparative efficacy of vaccines administered IM and intranasally, used alone or sequentially, to protect puppies from infection with Bordetella bronchiseptica and determine whether systemic or mucosal antibody response correlated with protection.

Design—Randomized controlled trial.

Animals—50 specific-pathogen-free Beagle puppies.

Procedure—In 2 replicates of 25 dogs each, 14-weekold puppies that were vaccinated against canine distemper virus and parvovirus were vaccinated against B bronchiseptica via intranasal, IM, intranasal-IM, or IMintranasal administration or were unvaccinated controls. Puppies were challenge exposed via aerosol administration of B bronchiseptica 2 weeks after final vaccination. Clinical variables and systemic and mucosal antibody responses were monitored for 10 days after challenge exposure. Puppies in replicate 1 were necropsied for histologic and immunohistochemical studies.

Results—Control puppies that were seronegative before challenge exposure developed paroxysmal coughing, signs of depression, anorexia, and fever. Vaccinated puppies (either vaccine) that were seronegative before challenge exposure had fewer clinical signs. Puppies that received both vaccines had the least severe clinical signs and fewest lesions in the respiratory tract. Vaccinated dogs had significantly higher concentrations of B bronchiseptica-reactive antibodies in serum saliva before and after challenge. Antibody concentrations were negatively correlated with bacterial growth in nasal cavity and pharyngeal samples after challenge exposure.

Conclusions and Clinical Relevance—Parenterally and intranasally administered vaccines containing B bronchiseptica may provide substantial protection from clinical signs of respiratory tract disease associated with infection by this bacterium. Administration of both types of vaccines in sequence afforded the greatest degree of protection against disease. (J Am Vet Med Assoc 2001;218:367–375)

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in Journal of the American Veterinary Medical Association