The metabolic responses of equine articular cartilage to incubation with bacterial lipopolysaccharide (LPS) were studied, using explant cultures of articular cartilage obtained from the metatarsophalangeal joints of 15 horses, age of which ranged from 3 months to 20 years. For comparison, explants were also established from the metatarsophalangeal joints of 3 calves. Explants were cultured for 3 days in medium containing various concentrations of LPS from 0 (control) to 100 microgram/ml. Glycosaminoglycan (GAG) released during the 3-day incubation was determined by a spectrophotometric assay, using the dye 1,9-dimethylmethylene blue. Newly synthesized GAG content was assayed by measuring [35S]sulfate incorporation during a 3-hour pulse labeling period. In addition, prostaglandin E2 (PGE2) synthesis was quantified, using a [3H]PGE2 radioimmunoassay kit and magnetic separation. Finally, explants from 3 animals were used to evaluate the effect of supplementing culture medium with 5% serum on the response of explants to LPS, and explants from 1 horse were used to compare responses to stimulation with LPS derived from 2 bacterial sources. Equine explants cultured with bacterial LPS had a dose-dependent decrease in synthesis and increase in release of GAG, and these responses were significantly (P < 0.0001) greater in explants from younger horses. In addition, equine explants had a significant (P = 0.0001) dose-dependent increase in concentration of PGE2 released into the culture medium in response to incubation with LPS. Comparison of data for GAG synthesis from equine and bovine explants revealed a significant (P = 0.025) difference in responsiveness to LPS between the 2 species. Equine explants tended to have a greater suppression of GAG synthesis in response to incubation with increasing concentrations of LPS than did age-corrected bovine samples.

A relation exists between colloid osmotic pressure and serum total protein concentration; equations describing this relation have been used to determine a calculated value for colloid osmotic pressure. However, the relation between total protein concentration and colloid osmotic pressure is altered by the method used to measure protein and by changes in the ratio of concentrations of albumin (A) to globulin (G). We developed nomograms for estimating colloid osmotic pressure from A and G concentrations, using samples obtained from clinically normal animals and compared the accuracy of these nomograms with that of previously described equations relating colloid osmotic pressure to total protein concentration. For comparison, serum samples from canine (n = 106), equine (n = 79), feline (n = 24), and bovine (n = 27) patients admitted to the University of Georgia Veterinary Medical Teaching Hospital were used. Results indicated that nomograms based on protein concentration estimated by a refractometer generally were the least reliable. Although predictive nomograms, using total protein concentration determined by the biuret method, provided better results for serum samples, there was considerable variation between measured and calculated values for colloid osmotic pressure in all species studied. Calculated values for colloid osmotic pressure derived from A and G concentrations were most closely related to measured values for colloid osmotic pressure in dogs, horses, and cats. However, calculated values for colloid osmotic pressure differed from measured values by as much as 5 mm of Hg for some samples by each of the methods of estimation. These results indicate that, although calculated values for colloid osmotic pressure may be most accurate when variations in the A-to-G ratio are accounted for in the nomogram, none of the calculation methods provided a consistently accurate estimate of colloid osmotic pressure.

Effect of estrogen (E2) and progesterone (P4) on uterine antibacterial activity and immunoglobulin concentrations in mares was studied. In 2 in vitro experiments, 6 mixed-breed mares were ovariectomized, and uterine fluid and blood serum were analyzed. Antibacterial assay methods were used to determine inhibitory effects on Streptococcus zooepidemicus of uterine fluid samples collected on days 3, 5, and 8, and serum obtained on day 8 of treatment. Single radial immunodiffusion methods were used to quantify amounts of IgA and IgG in uterine fluid and serum on days 3, 5, 8, and 14 of treatment. Neither E2 nor P4 increased activity of serum and uterine fluid against S zooepidemicus. Numbers of colony-forming units per milliliter of bacteria were significantly (P < 0.01) lower in control Hanks' balanced salt solution with 1.0% gelatin (HBSSG) than in uterine fluids. Bacterial numbers were significantly (50%) greater in uterine fluids and serum than in HBSSG controls for both treatments. Both fluids, especially serum, supported significantly (P < 0.01) more growth of S zooepidemicus than did HBSSG when incubated for 0, 2, and 4 hours. These findings are in contrast to previous reports of antibacterial activity in the uterus of sexually intact mares undergoing an estrous cycle: great reduction of bacterial count in uterine fluid from mares in diestrus, and significant increases in bacterial numbers in uterine fluid or serum from mares in estrus. Treatment comparisons between serum and uterine fluid IgA and IgG concentrations were not significantly different, although overall IgA concentration in the uterus was higher than concentration in serum. The IgG concentration in uterine fluid was higher in P4- than E2-treated mares. However, IgG concentration was significantly (P < 0.01) higher in uterine fluid on day 8 in P4-treated mares than on day 3 or 5. Results of this study indicate that neither immunoglobulin concentration nor hormone treatment has a direct effec.

Serum C-reactive protein (CRP) concentration was measured, using an automated immunoturbidimetric assay, in 44 clinically normal dogs and 67 dogs with band neutrophil count greater than or equal to 10(9) cells/L, and values were found to be significantly (P less than or equal to 0.05) different. Correlation of serum CRP concentration and band neutrophil count in the 67 dogs with greater than or equal to 10(9) band neutrophils/L resulted in a statistically significant P less than or equal to 0.05), but low correlation coefficient of 0.34. Serum CRP concentration and CBC values were determined for 6 clinically normal dogs undergoing anesthesia (controls) and 6 clinically normal dogs undergoing anesthesia and ovariohysterectomy. Significant alterations in CBC results and serum CRP concentration, compared with baseline values, were lacking in dogs of the control group. Serum CRP concentration was significantly (P less than or equal to 0.05) increased above baseline values in dogs undergoing surgery and was significantly (P less than or equal to 0.05) increased, compared with values in control dogs by 12 hours after surgery. In dogs undergoing surgery, serum CRP concentration was also significantly (P less than or equal to 0.05) different from values in control dogs at 28 and 36 hours, but not at the 76- and 124-hour sample collection times. Alterations in CBC values compatible with possible or convincing inflammation were detected in 83% of the dogs undergoing surgery at the 8- and 12-hour postsurgery sample collection times, 100% of dogs at 16, 22, 28, and 36 hours after surgery, 83% of dogs at 52 and 76 hours after surgery, 67% of dogs at 100 hours after surgery, and 0% of dogs at 124 hours after surgery It was concluded that significant increases in CRP, concentration in dogs with surgical trauma were not detected earlier than CBC alterations compatible with possible or convincing inflammation.

The alpha 1-proteinase inhibitors of trypsin, Spi1, Spi3A, and Spi3B, in bronchoalveolar lavage fluid (BALF) and serum of horses were separated by electrophoresis, and their proportions were quantified in 12 control horses and 12 with chronic obstructive pulmonary disease (COPD). A significantly lower proportion of Spi3B (P < 0.05) and higher proportion of Spi1 (P < 0.02 to P < 0.01) were detected in BALF, compared with serum, in control and COPD-affected horses and appeared to be attributable to reduced Spi3 activity in BALF. There was no significant difference between the control and COPD groups in this respect, indicating that the decrease in Spi3 may be a physiologic phenomenon. The differences observed may be associated with proteolytic damage to or preferential complex formation by Spi3.

A method for quantification of serum total IgE concentration in dogs by use of an ELISA containing monoclonal mouse anti-canine IgE was developed. Microtitration plates were coated with monoclonal mouse anti-canine IgE. Test sera and reference serum dilutions were added, followed by biotinylated monoclonal mouse anti-canine IgE. Avidin-alkaline phosphatase conjugate was added, and color development was measured spectrophotometrically, using a microtitration plate reader. Quantitative results were obtained by assigning to a reference serum a value of 100 IgE units/ml. Absorbance values of unknown samples were converted into IgE units by comparison with a standard curve generated by measurement of reference serum dilutions. Intra- and interassay coefficients of variation were 5 and 7%, respectively, and assay sensitivity was 1 U/ml. The assay was used to establish a normal range for total IgE concentrations in 30 healthy dogs. Total IgE concentration in healthy dogs followed a skewed distribution and ranged from < 1 to 91.2 U/ml, with a geometric mean value of 7.1 U/ml. The IgE concentration was remarkably stable in serum samples subjected to 25 freeze/ thaw cycles or incubation at approximately 25 C (room temperature) for up to 10 days. Comparison of total IgE concentrations in 23 serum samples assayed by use of double-overlay radial immunodiffusion and ELISA yielded correlation coefficient of 0.94. Comparison of the reference serum standard curve with serial dilutions of a purified IgE solution of known concentration yielded a range of values for the IgE unit of 0.7 to 2.0 micrograms.

A relation exists between colloid osmotic pressure and serum total protein concentration; equations describing this relation have been used to determine a calculated value for colloid osmotic pressure. However, the relation between total protein concentration and colloid osmotic pressure is altered by the method used to measure protein and by changes in the ratio of concentrations of albumin (A) to globulin (G). We developed nomograms for estimating colloid osmotic pressure from A and G concentrations, using samples obtained from clinically normal animals and compared the accuracy of these nomograms with that of previously described equations relating colloid osmotic pressure to total protein concentration. For comparison, serum samples from canine (n = 106), equine (n = 79), feline (n = 24), and bovine (n = 27) patients admitted to the University of Georgia Veterinary Medical Teaching Hospital were used. Results indicated that nomograms based on protein concentration estimated by a refractometer generally were the least reliable. Although predictive nomograms, using total protein concentration determined by the biuret method, provided better results for serum samples, there was considerable variation between measured and calculated values for colloid osmotic pressure in all species studied. Calculated values for colloid osmotic pressure derived from A and G concentrations were most closely related to measured values for colloid osmotic pressure in dogs, horses, and cats. However, calculated values for colloid osmotic pressure differed from measured values by as much as 5 mm of Hg for some samples by each of the methods of estimation. These results indicate that, although calculated values for colloid osmotic pressure may be most accurate when variations in the A-to-G ratio are accounted for in the nomogram, none of the calculation methods provided a consistently accurate estimate of colloid osmotic pressure. For clinical patients, colloid osmotic pressure based on these nomograms cannot replace direct measurement.

Effect of estrogen (E2) and progesterone (P4) on uterine antibacterial activity and immunoglobulin concentrations in mares was studied. In 2 in vitro experiments, 6 mixed-breed mares were ovariectomized, and uterine fluid and blood serum were analyzed. Antibacterial assay methods were used to determine inhibitory effects on Streptococcus zooepidemicus of uterine fluid samples collected on days 3, 5, and 8, and serum obtained on day 8 of treatment. Single radial immunodiffusion methods were used to quantify amounts of IgA and IgG in uterine fluid and serum on days 3, 5, 8, and 14 of treatment. Neither E2 nor P4 increased activity of serum and uterine fluid against S zooepidemicus. Numbers of colony-forming units per milliliter of bacteria were significantly (P < 0.01) lower in control Hanks' balanced salt solution with 1.0% gelatin (HBSSG) than in uterine fluids. Bacterial numbers were significantly (50%) greater in uterine fluids and serum than in HBSSG controls for both treatments. Both fluids, especially serum, supported significantly (P < 0.01) more growth of S zooepidemicus than did HBSSG when incubated for 0, 2, and 4 hours. These findings are in contrast to previous reports of antibacterial activity in the uterus of sexually intact mares undergoing an estrous cycle: great reduction of bacterial count in uterine fluid from mares in diestrus, and significant increases in bacterial numbers in uterine fluid or serum from mares in estrus. Treatment comparisons between serum and uterine fluid IgA and IgG concentrations were not significantly different, although overall IgA concentration in the uterus was higher than concentration in serum. The IgG concentration in uterine fluid was higher in P4- than E2-treated mares. However, IgG concentration was significantly (P < 0.01) higher in uterine fluid on day 8 in P4-treated mares than on day 3 or 5. Results of this study indicate that neither immunoglobulin concentration nor hormone treatment has a direct effect on streptocidal activity.