Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: Thomas J. Stabel x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Objective

To determine the most effective route and dose for 2-deoxy-D-glucose (2DG) administration in swine, kinetics of 2DG, endogenous glucose concentration in the blood, effects of 2DG on Cortisol concentration, and effects of 2DG administration in vivo on lymphocyte proliferation in vitro.

Animals

14 Salmonella-free male and female mixed-breed pigs.

Procedure

A cannula was inserted in the femoral artery of each pig to allow for frequent blood collection with minimal external stress. The concentration and duration of 2DG in the blood was monitored while varying dose (250, 500, or 750 mg/kg of body weight) and route (IV, SC, IM, or IP) of 2DG administration. Blood samples were collected at various time points and assayed for lymphocyte response to concanavalin A and Cortisol, endogenous glucose, and 2DG concentrations.

Results

The 2 best routes for administration of 2DG were IV and SC. If the IV route was chosen, the optimal dose was 500 mg of 2DG/kg; the optimal dose for SC administration was 750 mg/kg.

Conclusions

2DG induces a stress response in pigs similar to that in rodents. The use of 2DG in a porcine stress model should be effective for studying the possible role of stress in the pathogenesis and shedding of microorganisms. (Am J Vet Res 1999;60:708–713)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To establish the effect of dose on persistence of and immune response to Salmonella choleraesuis in swine.

Design

19 Salmonella-free pigs were allotted to 4 groups. Groups 1 (n = 5), 2 (n = 5), and 3 (n = 5) were inoculated intranasally with 109, 106, and 103 colony-forming units of S choleraesuis, respectively. Group 4 (n = 4) served as uninoculated controls.

Procedure

Pigs were monitored for clinical signs of disease and bacterial shedding. Serum and lymphocytes were obtained to measure immune responses. Pigs from groups 1, 2, and 4 were necropsied at postinoculation (PI) weeks 6 and 15. Pigs from groups 3 and 4 were necropsied at PI weeks 6 and 10.

Results

Pigs in group 1 shed S choleraesuis through PI week 15 and were tissue positive at PI weeks 6 and 15. Pigs in group 2 were tissue positive for S choleraesuis until PI week 6 and continued shedding through PI week 9. Salmonella choleraesuis was not recovered at any time from pigs in groups 3 or 4. Pigs in groups 1, 2, and 3 had serum IgG and IgM titers to S choleraesuis lipopolysaccharide and soluble antigens. Pigs in all groups had a lymphocyte response to concanavalin A, and pigs in groups 1 and 2 had a lymphocyte response to S choleraesuis endotoxin. Pigs in group 1 had a lower stimulation index in response to both antigens, indicating some form of lymphocyte immunosuppression.

Conclusions

Persistence of S choleraesuis in host tissues is dose dependent. Short-term persistence can occur after a dose as low as 106 colony-forming units of S choleraesuis. Higher doses result in development of longterm carrier status, which may be related to the observed lymphocyte immunosuppression.(Am J Vet Res 1996;57:313-319)

Free access
in American Journal of Veterinary Research

SUMMARY

A series of experiments was conducted to document tumor necrosis factor-α (tnf) activity in serum of swine after inoculation with Salmonella spp endotoxin and after oral or respiratory tract challenge exposure with live Salmonella spp. For experiment 1, a potentially lethal dose of S typhimurium endotoxin (25 μg/kg of body weight) was administered iv, and serum tnf activity was measured. High tnf (approx 700 IU/ml) activity at 1 to 2 hours after administration of the inoculum was associated with death, whereas lower tnf (approx 30 IU/ml) activity was associated with a general prolonged state of shock. For experiment 2, pigs were administered a nonlethal dose (5 μg/kg, iv) of either S typhimurium or S choleraesuis endotoxin. Difference in the ability to induce porcine serum tnf activity was not observed between strains. During experiment 3, pigs were inoculated with 104 colony-forming units of S typhimurium χ4232 either orally by gelatin capsule (gc) or by intranasal (in) instillation. A late serum tnf response (17 IU/ml) was measured at 6 weeks after in inoculation. A serum tnf response was not detected in gc-inoculated pigs. All tissues and feces were test-negative for S typhimurium prior to the 6-week tnf response. Serum tnf activity may be related to clearance of S typhimurium after respiratory tract exposure, but it is not important to or indicative of clearance of orally presented S typhimurium in swine. During experiment 4, pigs were inoculated with 106 colony-forming units of S typhimurium χ4232 similarly as for experiment 3. Challenge exposure with this medium-size dose of inoculum induced a prolonged peak serum tnf response (37 IU/ml) between 2 and 4 weeks after in inoculation. Again, serum tnf activity was not detected in gc-inoculated pigs. Data suggest that clearance of a medium-size dose (106) of inoculum may be influenced by the prolonged higher serum tnf activity. For experiments 5 and 6, pigs were inoculated in with 103, 106, 108, or 109 S choleraesuis χ3246. A measurable, yet statistically nonsignificant, serum tnf response was observed for all doses. Pigs inoculated by gc with 108 S choleraesuis χ3246 had similar results. High doses (> 106) of live S choleraesuis were associated with clinical signs of endotoxic shock. Clearance of S choleraesuis, or lack thereof, did not correlate with serum tnf activity.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To determine relative sensitivities of the PK(15)- and WEHI 164(13)-based bioassays for detection of tumor necrosis factor α (TNF).

Sample Population

Recombinant human, murine, and porcine TNF, and serum from pigs given endotoxin IV.

Procedure

Two cell lines were used as targets for recombinant human, murine, and porcine TNF cytotoxicity bioassays. Pigs were given sublethal doses of endotoxin to obtain serum samples containing high activity of porcine TNF. Serum TNF activity was tested, using both cell lines. Viable cells were detected by addition of dimethylthiazol diphenyltetrazolium bromide after 18 to 20 hours’ incubation with samples containing TNF.

Results

The 2 cell lines tested had different sensitivities to human, murine, and porcine TNF. Compared with WEHI 164(13) cells, PK(15) cells were 50 times less sensitive to murine TNF and 15 times less sensitive to human TNF. However, PK(15) cells were 4 times more sensitive to recombinant porcine TNF and 15 times more sensitive to porcine serum containing TNF.

Conclusions

The PK(15) cell line was more sensitive to porcine TNF-mediated lysis than was the WEHI 164(13) cell line. The PK(15)-based TNF bioassay will be especially useful for study of infectious disease processes in swine, particularly where low activity of TNF exists. (Am J Vet Res 1997;58:1115–1119)

Free access
in American Journal of Veterinary Research

Summary

Cutaneous reactivity to brucellin was evaluated in 10-month-old heifers vaccinated with low-virulence mutant strains of Brucella abortus and was compared with brucellin reactions in postparturient cows with active brucellosis. In the cows, the cutaneous lesion was characterized microscopically as severe, acute, serofibrinous vasculitis; dermal lesions at 6, 12, 25, and 48 hours after brucellin injection consisted of endothelial activation and perivascular exudation that led to progressive accumulation of fibrin, monocytes, macrophages, and lymphocytes. In vaccinated heifers, cutaneous tests were done, using standard brucellin, brucellin prepared from strain RB51, and the purified brucellar proteins-31K and superoxide dismutase. Negative-control cattle given saline solution, did not have cutaneous reactions. Standard brucellin induced the most marked reactions in vaccinated heifers. Brucellin from rough strain RB51 caused positive reactions in heifers vaccinated with strain 19, but reactions were variable in other groups. Skin lesions induced by purified superoxide dismutase and 31-kd proteins in vaccinated cattle were not acceptable for diagnosis. Marked variability of test responses in vaccinated cattle precludes field use of this test to determine vaccination status.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To clone, sequence, and express porcine recombinant soluble tumor necrosis factor receptor 1 (sTNFR1).

Procedure

A polymerase chain reaction (PCR)-based library enrichment technique was used to isolate a fragment of porcine TNFR1. The mature extracellular domain of porcine TNFR1 was subcloned into an expression vector and expressed in Escherichia coli as a fusion protein. Protein product was purified by immunoaffinity chromatography, using a commercially available affinity gel specific for the marker peptide of the fusion protein. The bioactivity of the purified protein was tested for its ability to inhibit TNF-mediated cytotoxicity in a PK(15) bioassay.

Results

A 927-base pair fragment of porcine TNFR1 encoding the entire extracellular and transmembrane domains, as well as 75 amino acids of the cytoplasmic domain, was isolated from a porcine lung cDNA library. The extracellular domain was expressed as a soluble TNFR1 fusion protein with a yield of 120 to 150 μg/L of culture. Affinity-purified porcine sTNFR1 was able to inhibit TNF-mediated cytotoxicity of porcine PK(15) cells in dose-dependent manner.

Conclusions

Porcine recombinant sTNFR1 inhibits TNF bioactivity in vitro. This recombinant protein will be useful for developing TNFR1 antibodies and studying the roles of TNF and TNFR1 in the pathogenesis of infectious diseases in swine. (Am J Vet Res 1998;59:1317–1322)

Free access
in American Journal of Veterinary Research