The role of silage feeding in the origin of an epizootic of encephalitic listeriosis in a sheep flock was investigated by use of a new direct Listeria-selective isolation and enumeration medium, in combination with serotyping and phage typing. The silage contained high numbers (about 10(6) cells/g) of a L monocytogenes strain indistinguishable with respect to serovar and phagovar from that isolated from the brains of sick sheep. These results provided unambiguous bacteriologic evidence of the epidemiologic link between silage consumption and listeriosis in ruminants.

An efficient, single-step method for purification of the 110-kilodalton (kDa) hemolysin of Actinobacillus pleuropneumoniae was developed. An immunoaffinity column was made by cross-linking murine monoclonal antibody 8C2 to the 110-kDa hemolysin of A pleuropneumoniae strain J45 serotype 5 to protein A-agarose beads. Purified hemolysin with high hemolytic activity was obtained after washing the column with phosphate-buffered saline solution, and eluting the hemolysin with 50 mM diethylamine, pH 11.0. The same column was also used to purify the hemolysin from A pleuropneumoniae strain 4074 serotype 1. The purification procedure could be completed within 5 hours, and almost 50% of the total hemolytic activity and hemolysin protein was recovered in pure form.

Ten multiparous sows were inoculated between 46 and 50 days of gestation with a fetal swine isolate of encephalomyocarditis virus (EMCV) to investigate the ability of the virus to cause transplacental infection and fetal death. Four sows (group 1) were inoculated IM with EMCV MN-25 that had been passaged 4 times on baby hamster kidney-21 line cell monolayers. Two sows were euthanatized at postinoculation (PI) day 23, and the other 2 sows at PI day 44. An additional 6 sows (group 2) were inoculated IM with the same virus that had been passaged 5 additional times in pigs. Two sows were euthanatized at 14 days, and the remaining 4 sows at PI day 28. Clinical signs were not observed in any of the sows, whereas all sows seroconverted to EMCV. In group 1, only 2 of 50 fetuses were mummified. Virus was not recovered, although EMCV antibodies were detected in the 2 mummified fetuses. In group 2, the 2 sows that were euthanatized at PI day 14 had 26 normal fetuses and there was no evidence of fetal infection. However, in the 4 sows euthanatized at PI day 28, 20 of 48 fetuses were mummified, hemorrhagic, or edematous. Encephalomyocarditis virus was recovered from 21 of 48 fetuses. Transplacental infection and fetal deaths in pregnant sows was achieved following infection with EMCV passaged in pigs.

The anterior chambers in 16 dogs with normotensive eyes and 3 Beagles with glaucomatous eyes were treated with 0, 25, 50, or 100 IU of bovine testicular hyaluronidase. Aqueous outflow resistance was then determined by constant-pressure perfusion of 0.9% NaCl solution for 30 or 60 minutes. In normotensive eyes, 25, 50, or 100 IU of hyaluronidase significantly (P < 0.02) increased the rate of constant-pressure perfusion compared with that of untreated eyes during 30- or 60-minute perfusions. Treatment of glaucomatous eyes with 25, 50, or 100 IU of hyaluronidase did not significantly increase the rate of constant-pressure perfusion over controls during a 30-minute perfusion. Bovine testicular hyaluronidase at all doses removed the staining of colloidal iron from the trabecular meshwork in normotensive eyes. In Beagles with glaucoma, the trabecular meshworks remained stained with colloidal iron when treated with the hyaluronidase, which suggested that some glycosaminoglycans were resistant to this enzyme's action.

The relation between average duodenal mast cell count, duodenal mucosal mast cell numbers, duodenal connective tissue mast cell numbers, circulating basophil numbers, heterophil-to-lymphocyte ratio, and lesion score were studied to gain an understanding of the events that may lead to intestinal lesion formation associated with hemorrhagic enteritis virus (HEV) infection. Changes in vascular permeability in the duodenum in birds inoculated with HEV were examined, using colloidal carbon and ferritin as vascular markers. Turkeys inoculated with HEV had significantly (P < 0.05) higher duodenal mast cell counts than did noninfected controls. Birds inoculated with HEV had significantly (P < 0.05) more mucosal mast cells than did phosphate-buffered saline solution-inoculated birds. Connective tissue mast cell and basophil numbers were unaffected by viral inoculation. Thermal stress did not have significant effect on lesion severity, but did increase number of birds that developed the characteristic intestinal lesions. The heterophil-to-lymphocyte ratio was significantly (P < 0.05) higher in HEV-inoculated birds, compared with phosphate-buffered saline solution-inoculated controls. Increase in vascular permeability was only detected in HEV-inoculated birds with intestinal lesions. Results indicate that mast cells, and the vasoactive mediators contained within mast cells, may be important in the early manifestation of HEV infection. They also provide a possible mechanism through which biochemical and physiologic changes characteristic of HEV infection can occur.

Plasma disposition and urinary recovery of sulfamethazine (SMZ), its N4-acetylated metabolite (N4AcSMZ), and 2 of its hydroxylated metabolites--5-hydroxysulfamethazine 5OHSMZ) and 6-hydroxymethylsulfamethazine (6CH2OHSMZ)--were determined in either sex of 4 animal species: rats, dwarf goats, rabbits, and cattle. Rats, rabbits, and dwarf goats had significant (P < 0.01) sex difference in SMZ plasma clearance. Male rats had higher plasma clearance than did female rats, and excreted higher amounts of the hydroxy metabolites and lower amounts of N4AcSMZ. The N4AcSMZ metabolite was predominant in plasma and urine of rabbits. Male rabbits had higher plasma clearance than did female rabbits, but differences in metabolite profile were not apparent. With regard to plasma SMZ elimination, the situation in goats was opposite to that in rats. Male goats had considerably lower clearance than did female goats. This was associated with a lower hydroxylation rate in males. Plasma half-life of SMZ in cows was lower than that in bulls, probably because of a smaller distribution volume in cows. Compared with elimination via urine, elimination via milk was negligible in cows. Significant differences in metabolite profiles were not found between bulls and cows. Similar to those in rats and mice, hormone-dependent xenobiotic metabolic pathways may exist in other species. Depending on species and xenobiotic compound residue concentrations of xenobiotics, their metabolites, or both may differ with sex of the animal, or may be altered after treatment with anabolic hormones.

Equine articular chondrocytes were isolated from explant cartilage cultures by digestion in a 0.075% collagenase solution for 15 to 19 hours. Cartilage from late-term fetal and neonatal foals resulted in mean chondrocyte yield of 51.99 X 10(6) cells/g of cartilage (wet weight), compared with a yield of 17.83 X 10(6) cells/g for foals 3 to 12 months old. Propagation of chondrocytes in monolayer and 3-dimensional culture was accomplished, using Ham's F-12 as the basal medium, with supplements of fetal bovine serum (10%), ascorbic acid, alpha-ketoglutarate, and L-glutamine. The medium was buffered with HEPES, and penicillin and streptomycin were added for microorganism control. In primary monolayer cultures of freshly isolated chondrocytes, the population doubling time was approximately 6 days. Dedifferentiation of chondrocytes toward a more fibroblastic-appearing cell was observed after the fifth passage (subculture), but was hastened by lower cell-plating density. Chondrocytes were frozen for periods of up to 9 months, using 10% dimethyl sulfoxide as the cryoprotectant. Cell viability of late-term fetal and neonatal foal chondrocytes after storage at -196 C decreased from 86% at 3 weeks to 31% at 12 weeks. Viability of cells derived from older foals and young adult horses was considerably better than that of cells from neonatal foals. Frozen chondrocytes can be stored for extended periods and thawed for immediate implantation or can be sustained in vitro in monolayer or 3-dimensional culture. Such cultures would be suitable for cartilage resurfacing experiments or in vitro assessment of various pharmaceuticals.

A standardized cortical defect was created on the caudal cortex of the proximal portion of each ulna in 5 adult mixed-breed dogs. One gram of autogenous cancellous bone graft (ACBG) was obtained from the greater tubercle of the ipsilateral humerus. The cortical defect in the ulna of 1 limb was filled with 1 g of ACBG that had been compressed with 2-MPa pressure for 30 seconds. One gram of noncompressed ACBG was placed into the contralateral ulnar cortical defect. The compressed and noncompressed ACBG recipient sites were radiographed at weekly intervals. Dogs were euthanatized 8 weeks after surgery, and the ACBG recipient sites were harvested for histomorphometric analysis. Optical densitometry was performed on all radiographs. There was no significant difference between compressed and noncompressed ACBG with optical densitometry or histomorphometric analysis for total bone area. We concluded that there was no difference in osteogenic capability between compressed and noncompressed ACBG of equal mass.

The relation of the glycated serum protein, fructosamine, to serum protein, albumin, and glucose concentrations was examined in healthy dogs, dogs with hypo- or hyperproteinemia, and diabetic dogs. Fructosamine was determined by use of an adaptation of an automated kit method. The reference range for fructosamine in a composite group of control dogs was found to be 1.7 to 3.38 mmol/L (mean +/- SD, 2.54 +/- 0.42 mmol/L). Fructosamine was not correlated to serum total protein, but was highly correlated to albumin in dogs with hypoalbuminemia. To normalize the data with respect to albumin, it is suggested that the lower limit of the reference range for albumin concentration (2.5 g/dl) be used for adjustment of fructosamine concentration and only in hypoalbuminemic dogs. In 6 hyperglycemic diabetic dogs, fructosamine concentration was well above the reference range. It is concluded that although fructosamine may be a potentially useful guide to assess the average blood glucose concentration over the preceding few days in dogs, further study is required to establish its value as a guide to glucose control in diabetic dogs.

Neutrophil migration through bovine teat tissues into the teat cistern, after endotoxin infusion into the teat cistern, was determined in vivo by 2 experimental procedures, indium-111 labeling of blood neutrophils, and obtaining multiple biopsy specimens from the teat cistern tissues. In both experiments, the number of leukocytes in the teat cistern flushing samples was continuously measured. A lag phase of approximately 1 hour was required between endotoxin infusion into the teat cistern and the first observed neutrophil accumulation in the teat tissues. The rate of neutrophil accumulation in the teat tissues was highest between postinfusion (pI) hours 1 and 2, and the accumulation process ceased after PI hour 3. Neutrophils migrated toward the epithelium, and intraepithelial neutrophils were observed beginning approximately 2 hours after infusion, which coincided with the first influx of cells into the teat cistern. The cell influx into the teat cistern increased continuously up to PI hour 3, peaked between PI hours 3 and 5, and was close to preinfusion value at PI hour 22. Use of indium-111-labeled neutrophils in the study of the inflammatory process provides a reliable noninvasive method to quantify cell migration in vivo. Use of biopsies allows quantification of the number of cells in different tissue areas, but has the disadvantage of being invasive. These 2 procedures complement each other, and could be of use in future studies of the local inflammatory process.