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- Author or Editor: James Collins x
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Abstract
Objective—To determine the effects of interleukin (IL)-1β on matrix synthesis and degradation by chondrocytes cultured in a 3-dimensional (3-D) gel medium.
Sample Population—Chondrocytes from 7 dogs.
Procedure—Articular chondrocytes were harvested and cultured in 3-D gel medium alone or with 10 or 20 ng IL-1βml that was added beginning on day 0, 3, 6, or 9. On days 3, 6, 12, and 20 of 3-D culture, samples of the liquid medium were evaluated for glycosaminoglycan (GAG), prostaglandin E2 (PGE2), and matrix metalloprotease (MMP)-3 content. The 3-D plug in each well was evaluated for histologic characteristics of viability, cell morphology, and proteoglycan staining, immunohistochemically stained for collagen type II, and spectrophotometrically analyzed for GAG content.
Results—Significant differences for all variables were detected between controls and each IL-1β group, among groups with different IL-1β concentrations, and among groups with IL-1β added at various time points. Chondrocytes exposed to IL-1β had loss of GAG, increased PGE2 and MMP-3 concentrations, and lack of collagen type-II synthesis. These IL-1β effects appeared to be time and concentration dependent.
Conclusions—Addition of IL-1β to chondrocytes in 3- D gel medium results in time- and concentrationdependent effects on matrix synthesis and degradation and provides an appropriate in vitro model for many of the pathophysiologic events associated with osteoarthritis. (Am J Vet Res 2000;61:766–770)
Abstract
Objective
To determine effects of glucosamine and acetylsalicylate on canine chondrocytes in 3-dimensional culture.
Sample Population
Chondrocytes isolated from articular cartilage of 2 adult female dogs recently euthanatized for reasons unrelated to orthopedic abnormalities.
Procedure
Chondrocytes were cultured in a 3-dimensional agarose-based medium alone (control), with glucosamine (100 μg/ml; GL), or with acetylsalicylate (18 µg/ml; AS). Supernatant and agarose plugs from 4 wells/group/d were collected on days 3, 6, and 12 of culture. Agarose plugs were evaluated for percentage of viable cells, percentage of cells producing pericellular or territorial matrix, glycosaminoglycan (GAG) concentration, and type-II collagen production. Prostaglandin E2 concentration in supernatants was determined.
Results
Chondrocytes in all groups had characteristics indicative of viability and differentiation; however, on day 12, a lower percentage of viable cells was detected in the AS group, compared with the other 2 groups. On day 6, GAG concentration in the AS group was significantly greater than concentrations in the other 2 groups. On day 12, GAG concentrations in the GL and AS groups were significantly less than in the control group. Within the GL and AS groups, cell viability was significantly less on day 12, compared with day 3. Significant differences in PGE2 concentration among or within groups and evidence of type II collagen production were not detected.
Conclusions
3-dimensional culture of canine chondrocytes allows for production of hyaline cartilage matrix constituents and growth of cells with morphologic characteristics similar to those of articular cartilage. Acetylsalicylate and glucosamine, at the single concentration evaluated, had detrimental effects on chondrocyte viability, GAG production, or both. (Am J Vet Res 1999;60:1546–1551)
Abstract
Objective—To determine the effects of varios concentrations of L-lysine and L-arginine on in vitro replication of feline herpesvirus type-1 (FHV-1).
Sample Population—Cultured Crandell-Reese feline kidney (CRFK) cells and FHV-1 strain 727.
Procedure—Uninfected CRFK cells or CRFK cells infected with FHV-1 were cultured in Dulbecco's modified Eagle's medium or in 1 of 7 test media containing various concentrations of lysine and arginine. Viral titer and CRFK growth rate were assessed in each medium.
Results—Media depleted of arginine almost completely inhibited viral replication, whereas 2.5 or 5.0 µg of arginine/ml of media was associated with a significant increase in FHV-1 replication. In media with 2.5 µg of arginine/ml, supplementation with 200 or 300 µg of lysine/ml reduced viral replication by 34.2 and 53.9%, respectively. This effect was not seen in media containing 5.0 µg of arginine/ml. Growth rates of CRFK cells also were suppressed in media containing these concentrations of amino acids, but they were not significantly different from each other.
Conclusions and Clinical Relevance—Arginine exerts a substantial growth-promoting effect on FHV-1. Supplementation of viral culture medium with lysine attenuates this growth-promoting effect in media containing low concentrations of arginine. Analysis of data from this study indicates that high concentrations of lysine reduce in vitro replication of FHV-1 but only in media containing low concentrations of arginine. Clinical trials will be necessary to determine whether supplemental administration of lysine, with or without arginine restriction, will be useful in the management of cats with FHV-1 infections. (Am J Vet Res 2000; 61:1474–1478)
Abstract
Objectives—To determine the sensitivity of bacteriologic culture of pooled fecal samples in detecting Mycobacterium paratuberculosis, compared with bacteriologic culture of individual fecal samples in dairy cattle herds.
Study Design—Cross-sectional study.
Animals—24 dairy cattle herds.
Procedure—Individual and pooled fecal samples were submitted for bacteriologic culture, and results were compared between these groups.
Results—Ninety-four and 88% of pooled fecal samples that contained feces from at least 1 animal with high (mean, ≥ 50 colonies/tube) and moderate (mean, 10 to 49 colonies/tube) concentrations of M paratuberculosis, respectively, were identified by use of bacteriologic culture of pooled fecal samples. Prevalences of paratuberculosis determined by bacteriologic culture of pooled and individual fecal samples were highly correlated.
Conclusions and Clinical Relevance—Bacteriologic culture of pooled fecal samples provided a valid and cost-effective method for the detection of M paratuberculosis infection in dairy cattle herds and can be used to estimate prevalence of infection within a herd. (J Am Vet Med Assoc 2003;223:1022–1025)
Summary
Embryonating eggs were inoculated with filtered porcine ileal mucosa containing intracellular curved rods (icr) and incubated for 4 to 6 days. Three of 12 pigs given the eggs per os developed microscopic lesions of proliferative enteritis (pe). Nonchallenge-exposed control pigs did not develop lesions of pe. Four of six positive control pigs given ileal mucosa from pigs with pe also developed microscopic lesions of pe. All of the PE lesions were found in pigs necropsied 10 to 29 days after challenge exposure. None of the swine in the study had clinical signs or gross lesions of pe.
Campylobacter spp were isolated from pigs with and without exposure to the ileal mucosa from pigs with pe. There was no relationship between Campylobacter spp isolation and development of lesions.
Deoxyribonucleic acids extracted from embryonating chicken eggs injected with the equivalent of 0.5 mg of mucosal lesions and incubated for 4 days hybridized to a dna probe specific for the icr, whereas dna extracted from 1.5 mg of mucosal homogenates of the same proliferative tissue did not hybridize with the same probe. Results of these experiments indicated that icr injected into eggs remained infective for pigs and suggest replication of icr in the first-passage eggs.
Abstract
OBJECTIVE
To evaluate the efficacy of the 3 major classes of anthelmintics used for the treatment of hookworms in dogs in the US and an extralabel treatment with an FDA-approved product for use in cats in a Labrador kennel with a history of persistent hookworm infections.
ANIMALS
22 dogs housed in a single kennel comprised of the following breeds: 19 Labrador Retrievers, 1 English Cocker Spaniel, 1 Chesapeake Bay Retriever, and 1 Boykin Spaniel.
PROCEDURES
We performed a fecal egg count (FEC) reduction test using 22 dogs that were allocated randomly to 1 of 5 treatment groups: pyrantel pamoate (Pyrantel pamoate suspension), fenbendazole (Safe-Guard suspension 10%), milbemycin oxime (Interceptor), moxidectin plus imidacloprid (Advantage Multi), and emodepside plus praziquantel (Profender topical solution for cats). FEC was performed on samples collected on days 0 and 11.
RESULTS
FEC reductions for the milbemycin oxime, moxidectin plus imidacloprid, and emodepside plus praziquantel groups were 43.9%, 57.4%, and 100%, respectively. The FEC increased following treatment for the pyrantel and fenbendazole groups.
CLINICAL RELEVANCE
These data demonstrate that the Ancylostoma caninum infecting the dogs in this kennel are highly resistant to all major anthelmintic classes approved for use in dogs in the US but are susceptible to emodepside. This was the first report of multiple anthelmintic drug–resistant A caninum in a dog kennel that does not involve Greyhounds.
Abstract
Objective—To determine efficacy and safety of a commercial modified-live canine distemper virus (CDV) vaccine used for prophylaxis in domestic ferrets.
Animals—Sixteen 16-week-old neutered male ferrets.
Procedures— Equal groups of ferrets were inoculated subcutaneously at 16 and 20 weeks of age with saline (0.9% NaCl) solution or a vaccine derived from the Onderstepoort CDV strain and attenuated in a primate cell line. Live virulent CDV was administered to all ferrets intranasally and orally 3 weeks after the second inoculation. Clinical signs and body weights were monitored regularly during the study. Blood samples for serologic examination were drawn prior to each inoculation, before challenge exposure, and 10, 15, and 21 days after exposure. Blood samples for reverse transcriptase polymerase chain reaction (RT-PCR) were obtained 5 days after the first vaccination, and 5, 10, 15, and 21 days after challenge exposure.
Results—After challenge exposure, control ferrets had significantly more clinical signs and weight loss, compared with vaccinates. All vaccinated ferrets survived, whereas all control ferrets died. The RT-PCR assay was successful in detecting CDV in blood and fresh or formalin-fixed tissues from infected ferrets.
Conclusions and Clinical Relevance—Findings suggest that the vaccine when given SC to domestic ferrets as directed is safe and protective against challenge exposure with virulent CDV. The RT-PCR assay may simplify detection of CDV in fresh and fixed tissues. (Am J Vet Res 2001;62:736–740)
Abstract
Objective—To determine the effect of experimental infection with bovine viral diarrhea virus (BVDV) on llamas and their fetuses, evaluate seroprevalence of BVDV in llamas and alpacas, and genetically characterize BVDV isolates from llamas.
Design—Prospective study.
Animals—4 pregnant llamas for the experimental infection study and 223 llamas and alpacas for the seroprevalence study.
Procedure—Llamas (seronegative to BVDV) were experimentally infected with a llama isolate of BVDV via nasal aerosolization. After inoculation, blood samples were collected every other day for 2 weeks; blood samples were obtained from crias at birth and monthly thereafter. For the seroprevalence study, blood was collected from a convenience sample of 223 camelids. Isolates of BVDV were characterized by reverse transcription- polymerase chain reaction assay.
Results—Viremia and BVDV-specific antibody response were detected in the experimentally infected llamas, but no signs of disease were observed. No virus was detected in the crias or aborted fetus, although antibodies were evident in crias after colostrum consumption. Seroprevalence to BVDV was 0.9% in llamas and alpacas. Sequences of the llama BVDV isolates were comparable to known bovine isolates.
Conclusions and Clinical Relevance—Findings suggest that llamas may be infected with BVDV but have few or no clinical signs. Inoculation of llamas during gestation did not result in fetal infection or persistent BVDV infection of crias. Seroprevalence to BVDV in llamas and alpacas is apparently low. The most likely source for BVDV infection in camelids may be cattle. (J Am Vet Med Assoc 2003;223:223–228)
