Search Results

You are looking at 1 - 10 of 43 items for

  • Author or Editor: L. L. Walker x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Objective—To determine whether previously unidentified variations of the SzP protein of Streptococcus equi subsp zooepidemicus were present in horses with various clinical signs of infection and whether any relationship could be identified between SzP protein variants and naturally occurring clinical conditions.

Sample Population—23 isolates of S equi subsp zooepidemicus were recovered from specimens of horses with various clinical conditions and used as a representative population of isolates for evaluation of different SzP protein variants.

Procedure—Genetic heterogeneity of the isolates was demonstrated by repetitive extragenic palindromic- polymerase chain reaction analysis. The SzP gene was sequenced and the presumed protein sequence determined for each isolate. Characteristics of the SzP proteins were compared among the isolates and in relation to the clinical conditions of horses from which they were recovered.

Results—The signal peptide types, number of proline- glutamic acid-proline-lysine repeats, and anchor sequences were consistent with those previously described for the SzP protein. Many of the isolates clustered with 5 previously described types on the basis of the hypervariable region of the SzP protein. One additional variant, which represented 8 of the isolates, was identified. Particular motifs in the hypervariable region accounted for many of the differences among hypervariable types.

Conclusions and Clinical Relevance—The SzP protein appears to be limited to a selected number of types. Variations in the SzP protein are frequently determined on the basis of different motifs rather than random amino acid substitutions. There does not appear to be any association of SzP protein variations and clinical manifestations of infection in horses. (Am J Vet Res 2003;64:976–981)

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

Abstract

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

Abstract

Objective

To characterize cytokine profiles and lymphocyte subpopulations in lung parenchyma and bronchoalveolar lavage (BAL) fluid from normal bovine lungs.

Animals

Eight 12- to 18-month-old cattle.

Procedure

Cell populations in BAL fluid and collagenase-digested lung parenchyma were analyzed by flow cytometry and monoclonal antibodies. Proportions of total cell populations were determined, using Giemsa-stained cytospots. Distribution of lymphocytes within the lung parenchyma was analyzed by immunohistochemistry, and cytokine mRNA species in the parenchyma were characterized by use of reverse transcriptase-polymerase chain reaction analysis.

Results

Cytokine profiles indicated high amounts of mRNA for interleukins 6 and 10 and transforming growth factor β. In the BAL fluid and lung parenchyma, macrophages were the predominant cell type, although the proportion was lower in the parenchyma. Lymphocytes made up approximately 3% of both cell populations. Common to both lung compartments was the predominance of CD2+ and γδ T cells over B lymphocytes. There were more CD8+ T cells than CD4+ T cells in both compartments. The γδ cells made up approximately 9% of the lymphocyte populations. Two-color flow cytometry revealed CD8+ γδ T cell and CD8+CD5 populations that were unique to BAL fluid. In the BAL fluid and parenchyma, most CD4+ and CD8+T cells expressed high amounts of CD44, a characteristic of memory T cells. The γδ T cells were CD44lo, as were B cells in the lung parenchyma. The B cells from BAL fluid expressed high amounts of CD44. Immunohistologic analysis of lung tissue revealed bronchus-associated lymphoid tissue structures with distinctive germinal center organization of B cells encompassed by CD4+ T cells.

Conclusions

Results provided normal values for comparison with those of other species and with the bovine respiratory tract response to disease. (Am J Vet Res 1997;58:969–975)

Free access
in American Journal of Veterinary Research

Summary

Hospital records and radiographs of 211 dogs and cats with vertebral column fractures or luxations evaluated at the University of Tennessee Veterinary Teaching Hospital between April 1977 and September 1985 were reviewed. After neurologic examination, status of the animal was graded on a scale of 1 to 8. Decision to treat each animal either medically or surgically was based on the extent and type of injury, neurologic signs, veterinarian’s experience, and owner’s wishes. After treatment, neurologic status was evaluated on the aforementioned scale and differences in the outcome of treatment were determined between surgically and medically treated groups, relative to initial neurologic status and location of the fracture.

Surgically treated animals had pretreatment mean (± sd) neurologic status (3.71 ± 1.35) that was slightly worse (P = 0.0079) than that of medically managed cases (5.16 ± 1.48). Animals of the surgically treated group improved significantly (P = 0.0122) more than did those of the medically treated group but after treatment, significant differences in neurologic status were not evident between surgically (6.67 ± 1.49) and medically (7.07 ± 1.24) treated animals. Medically treated animals required substantially longer to reach optimal neurologic status, but the average hospital stay was nearly twice as long for the surgically treated animals (13.5 days), compared with those treated medically (7.1 days). Animals with thoracic vertebral fractures had mean neurologic status that was worse than that in animals with cervical vertebral fractures (P = 0.0109). After either medical or surgical treatment, neurologic status did not differ among animals with cervical, thoracic, or lumbar vertebral fractures. Results of the study indicated that many vertebral fractures can be managed medically and that surgery should not always be the recommended treatment.

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

An oral vitamin E absorption test used in human beings was modified for use in horses. The most appropriate techniques with which to measure gastrointestinal tract absorption of vitamin E (α-tocopherol) in horses were developed. Vitamin E was administered orally, and serum values of α-tocopherol were measured by use of high-performance liquid chromatography at 0, 3, 6, 9, 12, and 24 hours after vitamin E administration. Variables included comparison of 2 dosages (45 and 90 IU/kg of body weight), routes of administration, and absorption dynamics of 3 preparations of dl-α-tocopherol. Absorption of the 2 doses of dl-α-tocopherol acetate indicated a dose response; the area under the curve at 24 hours (AUC24) was 4.3 μg-h/ ml for the 45-IU/kg dose and 32.2 μg-h/ml (P < 0.01) for the 90-IU/kg dose. Maximal absorption was apparent when vitamin E was naturally consumed in grain, compared with administration of identical preparations by stomach tube or paste. In the same horses, dl-α-tocopherol and dl-α-tocopherol acetate plus polyethylene glycol had statistically similar absorption curves and both had significantly greater AUC24, compared with dl-α-tocopherol acetate; values for the 3 compounds were 23.6, 25.8, and 12.6 μg-h/ml, respectively. The AUC24 varied between individual horses, but time of peak value was consistently observed between 6 and 9 hours.

On the basis of the data from this study, the recommended technique for performing the oral vitamin E absorption test in horses would be administration of 90 IU of the free form of dl-α-tocopherol/kg, mixed in 1 L of grain to horses from which food has been withheld for 12 hours, followed by allowing the horses ad libitum access to hay immediately after administration of the vitamin E. Three baseline serum α-tocopherol values should be obtained within 24 hours prior to the test, with the last sample being obtained just prior to administration of the test dose of vitamin E. Heparinized plasma also may be used for this testing procedure. α-Tocopherol concentration should be measured at 3, 6, 9, 12, and 24 hours after vitamin E administration.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate shedding patterns of Staphylococcus aureus, specifically the association between clonal relatedness and shedding patterns of S aureus for cows with naturally occurring S aureus intramammary infection.

Design—Longitudinal field study.

Sample—Milk samples from 22 lactating cows (29 mammary glands) of varied numbers of lactations on 2 dairies.

Procedures—Foremilk samples were collected weekly for 26 to 44 weeks during lactation from individual mammary glands. Milk samples were cultured bacteriologically with a 0.01-mL inoculum. Samples were considered culture positive for S aureus if ≥ 1 colony-forming units were obtained. Milk samples from known S aureus–positive mammary glands that were culture negative for S aureus or culture positive with a single colony of S aureus were cultured bacteriologically a second time with a 0.1-mL inoculum. Longitudinal shedding patterns of S aureus and the effect of strain type on ln(colony forming unit count) were examined.

Results—With the 0.01-mL inoculum, 914 of 1,070 (85%) samples were culture positive. After reculturing of negative samples with a 0.1-mL inoculum, 1,011 (95%) of the samples were culture positive. There was no significant difference in the detection of S aureus between genotypic clusters when either the 0.01- or 0.1-mL inoculum was used. There was no significant difference in the amount of shedding between mammary glands infected with isolates in genotypic cluster 1 or 2. No consistent shedding patterns were identified among or within cows. There was a significant difference in mammary gland linear score and test day (composite) linear score between mammary glands infected with isolates in genotypic clusters 1 and 2.

Conclusions and Clinical RelevanceS aureus was shed consistently in cows with naturally occurring intramammary infection in cows, and regardless of the pulsotype, variations in the amount of S aureus shedding had no significant effect on the ability to detect S aureus with a 0.1-mL inoculum.

Full access
in Journal of the American Veterinary Medical Association

SUMMARY

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