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  • Author or Editor: David A. Hart x
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Abstract

Objective—To determine relative amounts of mRNA expression of aggrecan, type-II collagen, matrix metalloproteinase (MMP) 1, and MMP3 in articular cartilage and synovial membrane samples from healthy equine joints and joints with osteoarthritis (OA) and to compare results of Northern blot hybridization with results of a reverse transcriptase-polymerase chain reaction (RT-PCR) assay.

Sample Population—Articular cartilage samples from 8 pairs of joints (1 with OA and 1 healthy) from 6 horses and synovial membrane samples from 6 pairs of joints from 5 horses.

Procedure—RNA was extracted from samples by use of a modified Trizol procedure. Northern blot hybridization and the RT-PCR assay were performed; results were quantitated by use of glyceraldehyde 3- phosphate dehydrogenase as an internal standard.

Results—Articular cartilage samples from joints with mild or moderate OA yielded less total RNA than samples from joints with severe OA. Northern blot hybridization indicated that type-II collagen mRNA expression in articular cartilage samples from joints with OA was significantly greater than expression in samples from healthy joints. The RT-PCR assay identified low levels of MMP3 mRNA expression in 4 of 8 sets of articular cartilage samples and 4 of 6 sets of synovial membrane samples, whereas Northern blot hybridization identified MMP3 mRNA expression in only 1 of 6 sets of articular cartilage samples and 1 of 6 sets of synovial membrane samples.

Conclusions—A RT-PCR assay is more sensitive than Northern blot hybridization for detection of MMP3 mRNA expression in articular cartilage and synovial membrane and requires smaller samples. (Am J Vet Res 2000;61:900–905)

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

Abstract

Objective—To characterize effects of intranasal inoculation of virulent Brucella melitensis strain 16M in mice.

Animals—Female Balb/c mice, 6 to 8 weeks old.

Procedure—Studies were designed to elucidate gross morphologic lesions, bacterial burden in target organs, and histologic changes in tissues following experimental intranasal inoculation of mice with B melitensis 16M, which could be used to characterize a model for testing vaccine efficacy.

Results—Measurable splenomegaly was evident at 3 and 7 weeks after inoculation. A demonstrable increase in splenic colony-forming units (CFU) from infected mice increased over time with increasing dose when comparing inocula of 103, 104, and 105 CFU. Recovery of brucellae from the lungs was possible early in infection with 101, 103, and 105 CFU, but only the group inoculated with 105 CFU consistently yielded quantifiable bacteria. At a dose of 101 CFU, few organisms were located in the spleen. Bacteria were recovered up to 140 days after inoculation in mice given 103 CFU. At an inoculum of 105 CFU, bacterial counts were highest early in infection. Histologic examination of tissues revealed an increase in white pulp and marginal zone in the spleen and lymphohistiocytic hepatitis.

Conclusion and Clinical Relevance—Changes in the spleen and liver increased with increases in dose and with increased time following intranasal inoculation with B melitensis 16M. Surprisingly, histologic changes were not observed in the lungs of inoculated mice. (Am J Vet Res 2001;62:398–405)

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in American Journal of Veterinary Research