Duration of immunity, efficacy and safety in sheep of a recombinant Taenia ovis vaccine formulated with saponin or selected adjuvants.

The efficacy and safety of a recombinant Taenia ovis protein was tested in sheep using 13 different adjuvant formulations, including oil adjuvants, aluminium salts, saponin, Iscoms and DEAE-dextran. The oil adjuvants, saponin and DEAE-dextran gave the highest antibody responses and greatest degree of protection against challenge infection with T. ovis eggs. Duration of immunity studies with a saponin based vaccine showed that highly significant protection (>90% reduction of cyst numbers) was achieved when sheep were challenge infected one month after immunisation. Significant protection (79%) was still present when sheep were challenged 6 months after immunisation. The optimum dose for this batch of saponin was 10 mg, which stimulated a peak antibody titre of 38,400, 4 weeks after immunisation and did not cause injection site reactions. Dialysed saponin was shown to retain its adjuvant properties and allowed an increase in dose to 30 mg without site reaction, resulting in a peak antibody titre of 51,200.     

Ketoprofen and phenylbutazone attenuation of PAF-induced lung inflammation in calves

The purposes of this study were: (1) to investigate which arachidonic acid metabolites contributed to platelet-activating factor (PAF) induced pulmonary dysfunction; and (2) to compare the effect of two non-steroidal anti-inflammatory drugs, phenylbutazone and ketoprofen in a model of PAF-induced reversible lung inflammation in six calves. In placebo and phenylbutazone groups, PAF infusion induced significant dysfunctions in the pattern of breathing, mechanics of breathing and gas exchange. These dysfunctions were prevented by ketoprofen pretreatment, except for the mechanics of breathing which was moderately but significantly altered by the PAF challenge. In all calves, leukotriene (LT) B4 plasma concentrations did not significantly increase above baseline values at any time. Prostaglandin (PG) E2 plasma concentrations showed a minor significant increase in phenylbutazone pretreated calves (55.8 +/- 25.8 pg/mL from 36.7 +/- 16.13 pg/mL). Thromboxane (TX) B2 plasma concentration was significantly increased during PAF challenge in placebo- and phenylbutazone-pretreated groups, but not in ketoprofen-pretreated calves (1580.0 +/- 1370 from 42.7 +/- 10.7 pg/mL; 2340 +/- 477 from 63 +/- 32 pg/mL; and 36.5 +/- 4.12 from 39.3 +/- 12.0 pg/mL, respectively). These data suggest that TXA2 is an important cyclooxygenase metabolite of arachidonic acid produced in response to PAF and that ketoprofen (intramuscular injection, 3 mg/kg) is more effective than phenylbutazone (intramuscular injection, 10 mg/kg) in preventing respiratory dysfunctions induced by the PAF challenge 30 min after drug administration. Ketoprofen did not suppress totally the PAF-induced changes in mechanics of breathing, which suggests that PAF or a secondary release of mediators could have a direct action on airway smooth muscle.     

Insulin-like growth factor binding protein-3: its biological effect on bovine granulosa cells

This study was aimed at testing the hypothesis that insulin-like growth factor binding protein (IGFBP)-3 can modulate hormone-dependent differentiation of granulosa cells in vitro. Granulosa cells from small (1 to 5 mm) follicles were collected from cattle, cultured for 2 d in medium containing 10% fetal calf serum, washed, and then treated for an additional 2 d in serum-free medium with follicle-stimulating hormone (FSH) (50 ng/ml), recombinant human IGF-I (0, 1.3, 4.0, or 13.3 nM), or recombinant human IGFBP-3 (0 to 4.26 nM). In one series of experiments, IGFBP-3 (0.53 and 2.13 nM) inhibited (51% to 92% decreases; P < 0.05) progesterone and estradiol production induced by 1.3 nM of IGF-I, but did not influence (P > 0.10) granulosa cell numbers or steroidogenesis in the absence of IGF-I. Only 4.26 nM of IGFBP-3 inhibited (by 35%) the increase in granulosa cell numbers induced by 1.3 nM of IGF-I. In another series of experiments, 13.3 nM of IGF-I, but not 4.0 nM of IGF-I, was able to completely overcome the inhibitory effect of 4.26 nM of IGFBP-3 on estradiol production. The increase in cell numbers induced by 4.0 and 13.3 nM of IGF-I was attenuated (P < 0.001) by 4.26 nM of IGFBP-3. In a third series of experiments, IGFBP-3 inhibited 125I-IGF-I binding to granulosa cells. These results indicate that IGFBP-3 has a pronounced inhibitory effect on IGF-I action in cultured bovine granulosa cells, and that this inhibitory effect is likely attributable to IGFBP-3 binding/sequestering IGF-I. Thus, IGFBP-3 may play a significant role in regulating granulosa cell proliferation and steroidogenesis during follicular development in cattle.     

Use of a water hardness test kit to measure serum calcium concentration in cattle

OBJECTIVE: To determine whether a commercially available water hardness test kit could be used to measure total serum calcium concentration and diagnose hypocalcemia in dairy cows. DESIGN: Prospective study. ANIMALS: 30 dairy cows from 19 commercial herds. PROCEDURE: Serum calcium concentration was determined using a water hardness test kit and a standard, laboratory-based method. Simple linear regression was used to determine whether there was a linear relationship between results of the 2 methods, and Spearman's rank correlation was used to calculate correlation between measurements. Sensitivity, specificity, and predictive values of using test kit-derived values for diagnosis of hypocalcemia (laboratory value < 8 mg/dl) were calculated. RESULTS: There was a high correlation and significant linear relationship between results of the 2 methods. Sensitivity, specificity, predictive value of a positive test result, and predictive value of a negative test result were 100, 73, 86, and 100%, respectively. Accuracy was improved by using a test kit-derived calcium concentration of 7 mg/dl as the cut-off for determining hypocalcemia. CLINICAL IMPLICATIONS: Results indicate that a commercially available water hardness test kit can be used as a rapid, inexpensive method of estimating serum calcium concentrations and diagnosing hypocalcemia in dairy cattle. However, the test is not practical for cow-side use, because blood samples must be centrifuged to obtain serum for use in the test kit.     

Effect of dietary n-6-to-n-3 fatty acid ratio on complete blood and total white blood cell counts, and T-cell subpopulations in aged dogs

OBJECTIVE: To determine effect of diets with variable n-6-to-n-3 fatty acid (FA) ratio on CD4+ and CD8+ T-lymphocyte subpopulations, and on results of routine laboratory analyses (CBC and total WBC count, serum biochemical analyses, and urinalysis). ANIMALS: 20 healthy, aged (9.5 to 11.5 years old) female Beagles. PROCEDURE: Dogs were fed 1 of 3 diets that contained 6% fat by weight but differed in amounts of n-6 and n-3 FA. For 11 weeks, 6 dogs were fed a low concentration of n-3 FA (ratio, 31:1), 7 were fed a medium concentration (5.4:1), and 7 were fed a high concentration (1.4:1). Preprandial blood and urine samples were collected before beginning the study and at 8 weeks for evaluation of laboratory variables. Before and at 3, 6, and 8 weeks during the study, blood was drawn for total WBC and lymphocyte counts and for characterization of T-cell subpopulations. At 8 and 10 weeks, dogs were vaccinated with keyhole limpet hemocyanin suspension. Blood was drawn 4 days after each vaccination, and lymphocytes were isolated for flow cytometry. Effects of diet and vaccination on each variable were determined. RESULTS: After vaccination, total lymphocyte count increased and CD4+ T lymphocyte count and the CD4(+)-to-CD8+ ratio decreased in dogs consuming the diet with n-6-to-n-3 FA ratio of 1.4:1. CONCLUSION: Feeding a diet with n-6-to-n-3 FA ratio of 1.4:1 had significant effects on CD4+ T lymphocytes in healthy, aged Beagles after vaccination.     

Seroprevalence of antibodies against gram-negative core antigens in rabbits, using an Escherichia coli J5 antigen-capture enzyme-linked immunosorbent assay

OBJECTIVE: To determine the seroprevalence of antibodies to gram-negative core antigens (GNCA) in specific-pathogen-free (SPF) rabbits (ie, free of Pasteurella multocida) and rabbits of undefined bacterial status (conventional). SAMPLE POPULATION: Serum samples were obtained from 7 groups of rabbits. The SPF rabbits comprised 2 adult groups and 1 immature group, whereas the 4 groups of conventional rabbits were all adults. PROCEDURE: A seroprevalence survey was conducted on rabbit sera for antibodies against GNCA, using an Escherichia coli J5 antigen-capture ELISA. RESULTS: Collective geometric mean titer (GMT) of adult rabbits was 1:6,463. The GMT of each of the 6 groups of adult rabbits was 1:956, 1:1,133, 1:4,525, 1:5,338, 1:7,669, and 1:25,600. Titers of populations differed significantly. CONCLUSION: Data analysis revealed there were anti-GNCA antibodies in rabbits. Similar to other species, the prevalence of IgM and IgG anti-GNCA antibodies increased with age. The IgG response was more marked than the IgM response. The SPF rabbits had lower IgG anti-GNCA titers than conventional rabbits, indicating possible cross-reactive epitopes between P multocida and Enterobacteriaceae. Rabbits with the highest anti-GNCA titers were those used in polyclonal antibody production, possibly stemming from endotoxin contamination of antigen or adjuvant. CLINICAL RELEVANCE: The possible cross-reactive antibodies directed at homologous wall components of Pasteurellaceae and Enterobacteriaceae could prove to be a possible heterotypic vaccination strategy for the protection of rabbits against pasteurellosis. Investigators should determine whether antigen impurity (endotoxin contamination) influences epitope focus during polyclonal antibody production and whether it affects sera variability among rabbits.     

In vitro dose-dependent effects of enrofloxacin on equine articular cartilage.

OBJECTIVE: To determine whether enrofloxacin has detrimental, dose-dependent effects on equine articular cartilage in vitro. ANIMALS: Cartilage explants were developed from 6 healthy horses between 0 and 96 months old. PROCEDURE: Patellar cartilage explants were incubated in 5 concentrations of enrofloxacin (2 microg/ml, 10 microg/ml, 1,000 microg/ml, 10,000 microg/ml, and 50,000 microg/ml) for 72 hours. Proteoglycan synthesis (Na35SO4 incorporation for 24 hours), proteoglycan degradation (Na35SO4 release for 72 hours), endogenous proteoglycan content (dimethylmethlene blue assay), and total protein content were determined. Cartilage explants were evaluated by use of histomorphologic and histomorphometric techniques (toluidine blue stain) for cytologic and matrix characteristics. Quantitative data were analyzed with a one-way ANOVA to compare results among various enrofloxacin concentration groups and the control group. A general linear model was used to determine whether age had an effect. RESULT: Proteoglycan synthesis was excellent in control specimens and in specimens incubated in low concentrations of enrofloxacin (2 microg/ml and 10 microg/ml). High concentrations of enrofloxacin (> 1,000 microg/ml) effectively eliminated proteoglycan synthesis regardless of horse age. Proteoglycan degradation at low concentrations (2 microg/ml and 10 microg/ml) was not different than control. High concentrations of enrofloxacin (> 1,000 microg/ml) caused significant degradation. Different concentrations of enrofloxacin did not affect endogenous proteoglycan. High concentrations of enrofloxacin were associated with a significant increase in number of pyknotic nuclei. CONCLUSION: Concentrations of enrofloxacin that might be achieved following systemic administration did not suppress chondrocyte metabolism in vitro. High concentrations of enrofloxacin (> 1,000 microg/ml) were toxic to chondrocytes.     

Wound contamination and antimicrobial susceptibility of bacteria cultured during total ear canal ablation and lateral bulla osteotomy in dogs.

OBJECTIVE: To detect contamination of wound sites from surgical handling of excised tissues during total ear canal ablation and lateral bulla osteotomy in dogs, and to compare susceptibility of bacterial isolates to cefazolin with susceptibility to other antimicrobial agents. DESIGN: Prospective clinical study. ANIMALS: 13 dogs. PROCEDURE: Dogs were treated surgically for otitis externa and media via total ear canal ablation and lateral bulla osteotomy. Specimens for aerobic bacterial culture were obtained from SC tissue immediately following skin incision, tissues excised from the osseous bulla (after transection of the horizontal ear canal and lateral bulla osteotomy), and from SC tissue prior to skin closure. Antimicrobial susceptibility of bacterial isolates to various antibiotics was determined by use of a broth dilution assay. RESULTS: There was a significant association between isolation of Streptococcus canis and Escherichia coli from specimens from the osseous bulla and specimens from the SC tissues prior to skin closure, indicating contamination of the SC tissues during surgery. Seventy percent of bacterial isolates were susceptible to cefazolin. CLINICAL IMPLICATIONS: Measures to limit bacterial contamination resulting from tissue handling during total ear canal ablation and lateral bulla osteotomy are necessary. Bacteriologic culture of tissue of the osseous bulla and determination of antimicrobial susceptibility are recommended. Administration of cefazolin alone may not be efficacious for antimicrobial prophylaxis.     

Influence of the three RN genotypes on chemical composition, enzyme activities, and myofiber characteristics of porcine skeletal muscle.

An experiment was conducted to evaluate the effects of the RN genotype on skeletal muscle characteristics in pigs sharing otherwise the same polygenic background. Animals were genotyped for RN on the basis of RTN (Rendement Technologique Napole) records using segregation analysis methods. Samples of longissimus (L) and semispinalis capitis (S) muscles were taken from 39 rn+/rn+, 38 RN-/rn+ and 37 RN-/RN- pigs slaughtered at 108 +/- 8.6 kg live weight. Activities of lactate dehydrogenase (LDH), citrate synthase (CS), and beta-hydroxy-acyl-coenzyme A dehydrogenase (HAD) were measured on both muscles to assess glycolytic, oxidative, and lipid beta-oxidation capacities, respectively. Histological examinations and chemical analyses were performed on L muscle. The energetic metabolism of the white L muscle was more oxidative in RN-/RN- than in rn+/rn+ pigs, as shown by increased CS and HAD activities (P < .001), decreased LDH activity (P < .001), larger cross-sectional area of IIA (P < .05) and IIB-red (P < .05) fibers, higher relative area of IIA fibers ( P < .05), and lower relative area of IIB-white fibers (P < .001). No significant difference was found between heterozygous and homozygous carriers of the RN- allele, except for CS activity, which was lower in RN-/rn+ than in RN-/RN- pigs. In L muscle, the RN- allele led to a large increase in glycolytic potential (+3.5 phenotypic SD between homozygotes) and lightness (+.7 SD), and a decrease in ultimate pH, dry matter, and protein contents (-1.7 to -2 phenotypic SD for these three traits), with an almost completely dominant effect. No differences were found between genotypes for intramuscular fat and hydroxyproline contents. In the red S muscle, the presence of RN- had no influence on enzyme activities. These results indicate that the RN genotype greatly influences compositional and histochemical traits and metabolic enzyme activities in a muscle type-dependent manner, with a completely or incompletely dominant effect of the RN- allele.