The effects of furosemide and pentoxifylline on blood flow properties in horses were investigated. Hematologic and rheologic changes were examined in 4 horses before and 3 minutes after administration of epinephrine (1 mg, IV). The next day, hemorheologic changes were determined before and 3 hours after administration of furosemide (1 mg/kg of body weight, IM), and after administration of epinephrine at the sampling at 3 hours. Hematologic and rheologic changes were evaluated weekly in 3 horses given pentoxifylline (8.5 mg/kg, q 12 h, PO) for 28 days. In addition, hemorheologic responses to epinephrine were determined on days 0, 14, and 28 of pentoxifylline treatment. Neutrophil filtration studies were also performed 2 hours after IV administration of pentoxifylline (8.5 mg/kg). Postepinephrine values for PCV, RBC and WBC counts, and blood viscosity were greater than preepinephrine values. Erythrocyte sedimentation rates decreased after epinephrine, whereas RBC filterability did not change. Treatment with furosemide was associated with increases in mean RBC hemoglobin concentration and blood viscosity. Filterability of RBC did not change. Treatment with pentoxifylline resulted in an increase in RBC filterability and erythrocyte sedimentation rate and a decrease in PCV; however, mean values for hematocrit and RBC count did not change. Treatment with pentoxifylline did not result in a change in resting blood viscosity, but markedly reduced the postepinephrine increase in blood viscosity. Neither IV nor orally administered pentoxifylline had an effect on neutrophil filtration. It was concluded that pentoxifylline has beneficial effects on RBC filterability and postepinephrine changes in blood viscosity, which may contribute to improvements of microcirculatory blood flow. In addition, furosemide may exacerbate exercise-associated hyperviscosity in horses.

Sandwich ELISA were developed to quantitatively determine conglutinin (CG), mannan-binding protein (MBP), and serum amyloid-P component (SAP) in the sera of cattle. The ELISA system was found to have high repeatability for quantitation of these serum proteins at concentration as low as 5 ng/ml. From results obtained for 10 healthy cows aged 2 to 7 years, mean +/- SD serum concentrations were 56.5 +/- 14.4 micrograms of CG/ml, 2.37 +/- 0.87 micrograms of MBP/ml, and 11.14 +/- 3.92 micrograms of SAP/ml, respectively. Values in 6 healthy heifer calves aged 6 months were 3.45 +/- 1.22 micrograms/ml for CG, 1.71 +/- 0.96 micrograms/ml for MBP, and 5.45 +/- 2.75 micrograms/ml for SAP, respectively. Concentrations in 9 healthy bullocks aged 6 months were 1.83 +/- 0.66 micrograms/ml for CG, 1.04 +/- 0.63 micrograms/ml for MBP, and 4.9 +/- 1.13 micrograms/ml for SAP, respectively.

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.

Enrofloxacin was administered orally to 6 healthy dogs at dosages of approximately 2.75, 5.5, and 11 mg/kg of body weight, every 12 hours for 4 days, with a 4-week interval between dosage regimens. Serum and tissue cage fluid (TCF) concentrations of enrofloxacin were measured after the first and seventh treatments. The mean peak serum concentration occurred between 1 and 2.5 hours after dosing. Peak serum concentrations increased with increases in dosage. For each dosage regimen, there was an accumulation of enrofloxacin between the first and seventh treatment, as demonstrated by a significant (P = 0.001) increase in peak serum concentrations. The serum elimination half-life increased from 3.39 hours for the 2.75 mg(kg dosage to 4.94 hours for the 11 mg/kg dosage. Enrofloxacin accumulated slowly into TCF, with peak concentrations being approximately 58% of those of serum. The time of peak TCF concentrations occurred between 3.8 hours and 5.9 hours after drug administration, depending on the dosage and whether it was after single or multiple administrations. Compared with serum concentrations (area under the curve TCF/area under the curve serum), the percentage of enrofloxacin penetration into TCF was 85% at a dosage of 2.75 mg/kg, 83% at a dosage of 5.5 mg/kg, and 88% at a dosage of 11 mg/kg. All 3 dosage regimens of enrofloxacin induced continuous serum and TCF concentrations greater than the minimal concentration required to inhibit 90% (MIC90) of the aerobic and facultative anaerobic clinical isolates tested, except Pseudomonas aeruginosa. Only the 11 mg/kg dosage regimen provided continuous serum and TCF concentrations that exceeded the MIC90 for P aeruginosa isolates; whereas none of the dosages induced serum or TCF concentrations greater than the MIC90 of the obligate anaerobic bacteria tested.

The duration of the incubation period for scrapie, a fatal transmissible neurodegenerative disorder of sheep and goats, is mainly determined by the Sip gene, which has 2 alleles (sA-susceptible and pA-resistant). A diagnostic test is not available to detect scrapie in live animals. We analyzed genomic DNA extracted from frozen sheep brains collected from Cheviot sheep of the United States that had been inoculated with the SSBP/1 scrapie inoculum. Digestion of the DNA with EcoRI or HindIII followed by the addition of a scrapie-associated fibril protein (PrP)-specific marker probe, yielded fragments of 6.8 (e1) and 4.0 (e3) kb, or 5.0 (h1) and 3.4 (h2) kb, respectively. Fragments e1 and h2 were associated with the histopathologic diagnosis of scrapie, and fragments e3 and h1 were associated with survival. A valine/alanine polymorphism within the PrP coding region that resulted in a BspHI site was further used to determine the genotype of these Cheviot sheep. Digestion of polymerase chain reaction fragments with BspHI resulted in an undigested fragment b- (0.840 kb), digested fragments b+ (0.460 and 0.380 kb), or both types of fragments. Survival time of b+/b+ homozygous sheep was significantly (P < 0.01) shorter (218 +/- 26.0 days) than survival time for b-/b- sheep (> 700 days after inoculation). Results indicated that b+ and b- are markers for the Sip sA and pA alleles, respectively. The intermediate duration of the incubation period for heterozygous sheep (b+/b-; 342.9 +/- 25.3 days) indicated that the Sip sA allele is expressed codominantly to the Sip pA allele.

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.

The mean area and minimal diameter of 3 histochemically determined myofiber types (1, 2A, and 2B; myosin ATPase in acid buffer) were calculated in middle gluteal muscle biopsy specimens from 62 stallions, 47 Andalusians and 15 Arabians, ranging in age from 6 to 12 years. Fourteen Andalusians and 7 Arabians were untrained, and the remainder were actively endurance-trained. The 6-month training schedules involved walking, slow trotting, and cantering. Fourteen Andalusians were moderately endurance-trained, whereas the other 19 Andalusians and 8 Arabians were strongly endurance-trained. Significant differences were not recorded between untrained and endurance-trained Arabians with respect to the area (type 1, 3,194 +/- 869 micrometers(2) and 3,150 +/- 370 micrometers(2); type 2A, 3,819 +/- 890 micrometers(2) and 3,380 +/- 356 micrometers(2); and type 2B, 4,872 +/- 962 micrometers(2) and 4,417 +/- 646 micrometers(2) or minimal diameter (type 1, 52.2 +/- 7.4 micrometers and 52.8 +/- 3.1 micrometers; type 2A, 58.1 +/- 6.7 micrometers and 55.0 +/- 2.8 micrometers; and type 2B, 65.3 +/- 6.4 micrometers and 63.4 +/- 4.3 micrometers) of the 3 fiber types, nor between untrained and endurance-trained Andalusians with respect to the area (untrained, 3,990 +/- 690 micrometers(2) moderately endurance-trained, 3,882 +/- 347 micrometers(2); and strongly endurance-trained, 3,758 +/- 510 micrometers(2)) and minimal diameter (untrained, 58.1 +/- 4.7 micrometers; moderately endurance-trained, 59.7 +/- 2.7 micrometers; and strongly endurance-trained, 58.7 +/- 4.5 micrometers) of 2A fibers. Moderately endurance-trained Andalusians had larger 2B fibers (area 18.6%; minimal diameter 14.3%) than untrained Andalusians, and the minimal diameter of type-1 and type-2B fibers was greater in strongly endurance-trained Andalusians than in untrained Andalusians (9.5% for type 1; 10.0% for type 2B). These results suggest minimal effects of endurance training on the myofiber size of adult Andalusians and Arabians, but a tendency toward increased type-1 and -2B fiber size was found for Andalusians.

Quantitative immunodiffusion in one dimension was performed in 6-mm Duran tubes containing a 1% Nobel agar solution and various dilutions of antisera. A series of dilutions of pure myoglobin in equine sera as well as plasma from horses with rhabdomyolysis were tested. Standard curves were prepared of the migration distance of the formed precipitate from the meniscus of the gel after 3, 6, 12, and 24 hours. The clearest line of precipitate was formed with a 1:20 dilution of antisera in agar. Standard curves were nonlinear and plasma myoglobin could be detected at 2 micrograms of myoglobin/ml or greater. The test was optimal, with an error of 5.6%, when read at 24 hours at approximately 25 C. Tubes with agar could be stored for 6 months at 4 C without affecting the accuracy of the test. The specificity of myoglobin for skeletal or cardiac muscle, and its rapid clearance from serum after muscle necrosis, make it ideally suited for evaluating acute muscle damage and for testing the susceptibility of horses for rhabdomyolysis following an exercise test.

Contact wide-field specular microscopy was performed on eyes of 16 healthy dogs after tissue plasminogen activator at a concentration of 25 microgram/100 (group 1, n = 8) or 50 microgram/100 microliter (group 2, n = 8) was injected into 1 anterior chamber of each dog. The contralateral eye served as a nontreated control. Applanation tonometry was used to measure intraocular pressure in both eyes for up to 168 hours. By use of computerized morphometric analysis and pachymetry, changes from baseline values in endothelial cell density, cell morphologic features, and corneal thickness were evaluated at postinjection, hours 24, 48, and 168. Significant mean differences in intraocular pressure were not detected between treated eyes of group-1 dogs and those in group 2 at designated times, or between treated and nontreated eyes of dogs in either group. Mean corneal thickness of treated and nontreated eyes was similar in both groups through postinjection hour 168. Changes in mean percentage of endothelial cell sides were observed only in treated eyes of group-2 dogs, with the mean percentage of hexagons at postinjection hour 168 decreasing by 18%, a decrease that was significantly (P < 0.05) greater than the decrease in nontreated eyes. The mean percentage of 6-sided cells in treated eyes of group-2 dogs was significantly (P < 0.05) less than that in treated eyes of group-1 dogs at postinjection hour 168.

Experimental and field trials were conducted to evaluate an ELISA for its ability to detect Trichinella-infected domestic swine and to compare ELISA results with muscle-digestion test results. The ELISA used was a commercial double-antibody kit, containing an excretory-secretory antigen, and was evaluated principally for epidemiologic use. Experimentally induced infection in swine (4 groups of 3 pigs each; inoculated with 0, 50, 500 or 5,000 larvae) was detected as early as postinoculation week 4, with seroconversion of all inoculated swine by postinoculation week 8. The rate of seroconversion appeared to be by initial larval dose, time after inoculation, and immunocompetence of the individual host. Determination of antibody kinetics generally revealed rapidly increasing antibody titer, followed by its steady decrease in most pigs. Once seropositive, however, all pigs remained seropositive for the duration of the 10-week study. Presence of muscle larvae was confirmed in all infected pigs at termination of the study. We recognize that the experimental conditions may not be truly representative of those under which natural infection develops in pigs; however, the ELISA detected an infected pig with muscle larval density of 0.87 larvae/g of tissue. Results of a field trial (n = 310) indicated no muscle digestion test-positive pigs (35 g of diaphragm muscle digested/pig), but 3 samples tested positive by ELISA for specificity of 99.0%.