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Objective—To determine the organisms most commonly isolated from pleural fluid from dogs and cats with pyothorax.

Design—Retrospective study.

Animals—51 dogs and 47 cats.

Procedure—Results of bacteriologic culture of pleural fluid samples obtained by means of thoracentesis were obtained from medical records. To obtain information on in vitro antimicrobial susceptibility of organisms commonly isolated from dogs and cats, records of all dogs and cats examined during 1998 were reviewed, and information was obtained on identity and in vitro antimicrobial susceptibility of aerobic organisms isolated from samples other than urine or urinary tract samples.

Results—Median ages of dogs and cats were 4 years. Bacteria were isolated from pleural fluid samples from 47 of 51 (92%) dogs and 45 of 47 (96%) cats. Obligate anaerobic bacteria were isolated from 28 dogs and 40 cats. A mixture of obligate anaerobic and facultative bacteria was isolated from 17 dogs and 20 cats. Samples from cats most often yielded a member of the nonenteric group (most commonly members of the genus Pasteurella), whereas those from dogs more often yielded a member of the family Enterobacteriaceae (most commonly E coli).

Conclusion and Clinical Relevance—Results suggest that antimicrobial agents chosen for the initial treatment of dogs and cats with pyothorax should be active against a mixture of obligate anaerobic and facultative bacteria. (J Am Vet Med Assoc 2000;216: 359–363)

Full access
in Journal of the American Veterinary Medical Association


We investigated whether stromelysin activity in the medium of canine articular cartilage explants is associated with proteoglycan degradation in these explants. Cartilage explants were treated with recombinant human interleukin 1α (rh-il-lα), lipopolysaccharide, or canine monocyte-conditioned medium. Proteoglycan synthesis and degradation were measured. Metalloproteinase activity (inhibitable by tissue inhibitor of metalloproteinase 2) in the culture medium was measured by use of fluorimetry with a quenched fluorescent substrate. Western blots of the medium were probed with polyclonal antibodies to human stromelysin, collagenase, and gelatinase.

Neither metalloproteinase activity nor proteoglycan degradation were inducible in canine cartilage explants treated with rh-ll-1α. However, proteoglycan synthesis was significantly (P < 0.05) decreased by concentrations of 10 and 100 ng of rh-il-1α/ml. Metalloproteinase activity in the medium accompanied proteoglycan degradation of cartilage treated with lipopolysaccharide and monocyte-conditioned medium. The metalloproteinase released into the medium was identified as prostromelysin by results of western blotting.

Free access
in American Journal of Veterinary Research


To determine whether ampicillin- and tetracycline-resistant strains of Pasteurella multocida and P haemolytica isolated from California cattle with pneumonia were spatially and temporally clustered and to compare overall estimates of percentages of these isolates resistant to these antimicrobials with estimates obtained on the basis of regional and temporal information.


Epidemiologic study.

Sample Population

Records of P multocida and P haemolytica isolates obtained from lung or tracheal wash samples collected from California cattle with pneumonia between July 1, 1991 and July 31, 1996. Only isolates obtained from samples submitted by dairies and calf ranches were used.


Spatial clustering of ampicillin- and tetracycline-resistant isolates was assessed by use of nearest-neighbor and Cuzick and Edwards' analyses. Linear clustering along a north-south line was assessed by use of runs and maximum length of runs tests. Temporal clustering was assessed by use of scan tests. Spatial-temporal clustering was assessed by use of Barton's method. Regional estimates of percentages of P multocida and P haemolytica resistant to ampicillin or tetracycline were calculated.


There was significant spatial clustering of resistant isolates and significant linear clustering along a north-south line. Significant differences in regional estimates of percentages of antimicrobial-resistant isolates were found.

Clinical Implications

Results support the hypothesis that antimicrobial-resistant organisms can be clustered at the local level and reinforce the need to establish regional estimates of percentages of bacterial isolates that will be susceptible to commonly used antimicrobials. (J Am Vet Med Assoc 1998;212:1001–1005)

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in Journal of the American Veterinary Medical Association


Objective—To optimize the isolation and culture of mesenchymal stem cells (MSCs) from umbilical-cord blood (UCB), identify variables that predicted successful MSC isolation, and determine whether shipping, processing, and cryopreservation altered MSC viability, recovery rates, and expansion kinetics.

Sample Population—UCB samples from 79 Thoroughbred and Quarter Horse mares.

Procedures—UCB samples were processed to reduce volume and remove RBCs. Nucleated cells (NCs) were cryopreserved or grown in various culture conditions to optimize MSC monolayer expansion and proliferation. Donor and UCB-sample factors were analyzed to determine their influence on the success of MSC isolation and monolayer expansion.

Results—MSCs capable of multilineage in vitro differentiation were expanded from > 80% of UCB samples. Automated UCB processing and temperature-controlled shipping facilitated sterile and standardized RBC reduction and NC enrichment from UCB samples. The number of NCs after UCB samples were processed was the sole variable that predicted successful MSC expansion. The UCB-derived MSCs and NCs were successfully cryopreserved and thawed with no decrease in cell recovery, viability, or MSC proliferation. The use of fibronectin-coated culture plates and reduction of incubator oxygen tension from 20% to 5% improved the MSC isolation rate. Some UCB-derived MSC clones proliferated for > 20 passages before senescence. Onset of senescence was associated with specific immunocytochemical changes.

Conclusions and Clinical Relevance—Equine UCB samples appeared to be a rich source of readily obtainable, highly proliferative MSCs that could be banked for therapeutic use.

Full access
in American Journal of Veterinary Research