bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood ionized calcium concentrations in horses before and after the cross-country phase of three-day event competition
Authors: Geiser Dennis Richard , Andrews Frank Michael , Rohrbach Barton W. , White Susan Laraine , Maykuth Patricia L. , Green Eleanor Myers , Provenza Melanie Kay
Published: January 2024

Blood ionized calcium (Ca2+) and pH; plasma lactate concentrations; and total protein, total calcium (CaT), albumin, and phosphorus concentrations in serum were determined in 40 healthy horses before (T1), at the finish line (T2), and 10 minutes after the finish (T3) of the cross-country phase of a 3-day-event competition. Mean (± sem) Ca2+ concentrations decreased from 6.22 ± 0.04 mg/dl at T1 to 5.04 ± 0.07 mg/dl at T2 (P ≤ 0.05). This decrease was accompanied by a nonsignificant increase in CaT between T1 and T2. The mean (± sem) percent ionization of calcium decreased significantly (P ≤ 0.05), from 50.9 ± 2.75% at T1 to 40.3 ± 3.58% at T2. Significant increases in mean albumin, total protein, phosphorus, and lactate concentrations and a significant decrease in mean pH were observed at T2 (P ≤ 0.05). At T3, mean Ca2+ and percent ionization had increased, but remained significantly less than resting values. Mean CaT was significantly decreased at T3, compared with values at T1 and T2. Correlation of mean Ca2+ concentration with all other measured variables at each time was evaluated; correlation coefficients between mean Ca2+ and all other variables were low (r2 ≤ 0.38), indicating low biological significance.
Ultrastructural changes in ovarian follicles of monkeys administered hexachlorobenzene
Authors: Bourque Andrea C. , Singh Amreek , Lakhanpal Neeraj , McMahon Avril , Foster Warren G.
Published: January 2024

Objective

To test hexachlorobenzene (hcb), an environmental pollutant, for its potential toxicity to the ovary.

Design

Nonhuman primates were orally administered the pollutant at doses between 0.01 and 10 mg of hcb/kg of body weight to test viability of ovarian follicles. At the end of dosing period, the monkeys received a compound that contained follicle-stimulating and luteinizing hormones to stimulate development of follicles that would be examined by electron microscopy.

Animals

Twenty, 6- to 13-year-old cynomolgus monkeys were randomly assigned to 5 groups.

Procedure

The hcb, in concentrations of 0.01, 0.1, 1.0, and 10.0 mg/kg, was orally administered with glucose in gelatin capsules for 13 weeks. Monkeys receiving capsules containing glucose only served as controls. After the 13th week, monkeys were given a compound that contained follicle-stimulating and luteinizing hormones daily during days 2 to 7 from the start of menses. On day 8 of the menstrual cycle, 5,000 IU of human chorionic gonadotropin was administered, and 35 to 38 hours later, 1 ovary from each monkey was obtained during laparotomy. Approximately 1-mm cubes of tissue from each ovary were harvested, fixed by immersion in buffered 2% glutaraldehyde, and processed for transmission electron microscopy.

Results

Ultrastructure of ovarian follicles was altered in the monkeys administered hcb. Lesions were observed in the follicles from monkeys given the lowest concentrations of hcb, and comprised condensed mitochondria in the developing ova and follicular cells that contained nuclei with deep indentations and abnormal accumulation of cytoplasmic lipid droplets. Alterations, such as herniation of the ooplasm, degeneration of the follicular cells, and appearance of abnormal spaces between follicular cells were observed in the follicles from monkeys of the 0.1 to 1.0 mg of hcb/kg dosage groups. The most relevant alterations were seen in the mitochondrion, an organelle that appeared to be most sensitive to the compound. Mitochondria were condensed, with abnormal intracristal spaces in the lower-dosage groups, and were markedly degenerated in the 10 mg/kg group. The effects of hcb were dose-related.

Conclusion

The hcb is a reproductive system toxicant, and its damaging effects may be a result of augmentation of lipid peroxidation, especially in the primary follicle, which abnormally affects cellular membranes and thus, impairs their permeability.
Evaluation of a single injection method, using iohexol, for estimating glomerular filtration rate in cats and dogs
Authors: Brown Scott A. , Finco Delmar R. , Boudinot F. Douglas , Wright Jennifer , Tarver Stacy L. , Cooper Tanya
Published: January 2024

Objective

To evaluate the utility of a method for estimating glomerular filtration rate (GFR) after single IV administration of iohexol.

Design

The plasma clearance of iodine (PCI), taken as the quotient of the administered dose of iodine (300 to 600 mg of l/kg of body weight) divided by the area under the plasma iodine concentration versus time curve determined by 4 methods (PCI1–PCI4). The results for PCI were compared with simultaneously obtained values for the urinary clearance of exogenously administered creatinine (CCr), a widely accepted method for the measurement of GFR in cats and dogs.

Animals

Cats and dogs that were renal intact (n = 5 cats; n = 1 dog) or had renal mass reduced by partial nephrectomy (n = 5 cats; n = 7 dogs).

Results

Values for PCI were closely related (R2 values ranged from 0.947 to 0.992; P < 0.0001 in all cases) to CCr. Despite this close correlation between CCr and PCI, the 95% confidence interval for the difference between PCI3 and CCr included values that exceeded 1.4 ml/min/kg, which represents 50% of the mean value for CCr in renal-intact cats.

Conclusions

Determination of PCI provided a reliable estimate of GFR in cats and dogs of this study. However, differences between 1 of the methods (PCI3) and CCr are clinically important, emphasizing the need to use more than simple linear regression analysis and correlation coefficients when attempting to validate new measurement techniques.

Clinical Relevance

The determination of PCI provided a reliable estimate of GFR in cats and dogs of this study. (Am J Vet Res 1996;57:105-110)
Effect of craniectomy/durotomy alone and in combination with hyperventilation, diuretics, and corticosteroids on intracranial pressure in clinically normal dogs
Authors: Bagley Rodney S. , Harrington Michael L. , Pluhar G. Elizabeth , Keegan Robert D. , Greene Stephen A. , Moore Michael P. , Gavin Patrick R.
Published: January 2024

Objective

To determine the effect of craniectomy and durotomy on intracranial pressure (ICP) in clinically normal dogs.

Design

Two-part study (experiments A and B) involving craniectomy and durotomy, with and without treatments to lower ICP.

Animals

Six (experiment A) and 7 (experiment B) healthy dogs.

Procedure

In experiment A, craniectomy was performed in combination with durotomy, diuretic administration, methylprednisolone sodium succinate administration, and hyperventilation, and effect of these manipulations on ICP was determined. In experiment B, dogs had only craniectomy and durotomy without associated ICP-lowering treatments. During both experiments, ICP was monitored throughout the surgical procedure with a fiber optic ICP monitoring device.

Results

Intracranial pressure decreased after the combination of craniectomy, durotomy, and other ICP-lowering treatments in dogs of experiment A. Similar magnitude of decrease in ICP was observed in dogs of experiment B after craniectomy and durotomy.

Conclusions

Comparison of these experiments indicate that surgical removal of overlying skull and incision of the dura mater can significantly decrease ICP in clinically normal dogs.

Clinical Relevance

Craniectomy and durotomy may be useful as an adjunct treatment for increased ICP. (Am J Vet Res 1996;57:116-119)
Use of enzyme-linked immunosorbent assay and radioimmunoassay to determine serum and urine dexamethasone concentrations in Thoroughbreds after intravenous administration of the steroid
Authors: Chen C. L. , Zhu D. , Gillis K. D. , Meleka-Boules M.
Published: January 2024

Objective

To develop a simple and sensitive ELISA for detection of dexamethasone in horse serum and urine.

Sample Population

Blood and urine samples from 3 Thoroughbred mares.

Procedure

A dexamethasone oxime was prepared and conjugated to hemocyanin, bovine serum albumin and to horseradish peroxidase. One- and two-step double-antibody ELISA methods, as well as a radioimmunoassay method, were performed. The one-step ELISA was used to test urine from 3 Thoroughbred mares injected with 5 mg of dexamethasone, IV.

Results

The ELISA could detect dexamethasone in the range of 0.01 to 50 ng/ml, with intra- and interassay variations of 8.92 and 9.42%, respectively. Serum dexamethasone concentration reached a peak of 20 to 35 ng/ml 15 minutes after steroid administration and decreased to 1 ng/ml in 2.5 hours. Urine dexamethasone concentration 18 to 50 ng/ml 1 to 2 hours after drug administration and decreased to 1 ng/ml at 10 hours.

Conclusion

The developed assay is sensitive as well as simple for detecting dexamethasone in horse serum and urine, and is comparable to radioimmunoassay.

Clinical Relevance

This method can be useful for screening samples from racehorses, because it is sensitive and does not require sample preparation or sophisticated equipment.
Intratumoral administration of carboplatin for treatment of squamous cell carcinomas of the nasal plane in cats
Authors: Théon Alain P. , VanVechten Melinda K. , Madewell Bruce R.
Published: January 2024

Objective

To develop a slow-release carboplatin formulation for intratumoral administration to cats.

Design

Preliminary study to analyze pharmacokinetic effects of purified sesame oil in the carboplatin formulation for intratumoral administration, and a second study to evaluate the efficacy and toxicosis of intratumoral administration of carboplatin in purified sesame oil.

Animals

23 cats with squamous cell carcinomas of the nasal plane.

Procedure

Eight cats with advanced-stage tumors were submitted to intratumoral administration of 100 mg of carboplatin/m2 of body surface area, with or without purified sesame oil, using a two-period, cross-over design. Fifteen additional cats were treated by intratumoral administration of carboplatin in purified sesame oil. Four weekly intratumoral chemotherapy injections of carboplatin in purified sesame oil at a dosage of 1.5 mg/cm3 of tissue were given.

Results

Purified sesame oil in the formulation significantly reduced systemic exposure to carboplatin and drug leakage from the sites of injection. Cumulative effects of repeated intratumoral administrations on plasma concentrations of carboplatin were not observed. Systemic toxicosis was not observed, and local toxicosis was minimal. Healing of ulcerated lesions was not compromised. Rates of complete clinical tumor clearance and complete response were 67 and 73.3%, respectively. Product-limit estimates of mean progression-free survival times was 16 ± 3.3 months. The 1-year progression-free survival rate was 55.1 ± 13%. Local recurrence was observed in 7 cats; 4 had marginal tumor recurrence, and 3 had in-field and marginal tumor recurrence.

Conclusions

Intratumoral carboplatin chemotherapy is safe and effective for cats with squamous cell carcinoma of the nasal plane. Future studies to improve treatment efficacy could include evaluation of increased dose-intensity as well as combination of this modality with radiotherapy.

Clinical Relevance

Intratumoral administration of carboplatin in a water-sesame-oil emulsion was found to be a practical and effective new treatment for facial squamous cell carcinomas in cats.
Isolation and characterization of α1-protease inhibitor from canine plasma
Authors: Melgarejo Tonatiuh , Williams David A. , Griffith G.
Published: January 2024

Objective

To improve a previously described purification process by producing a higher yield and purity of α1-protease inhibitor (α1-PI) from canine plasma.

Animals

Plasma pool from 10 clinically normal male dogs.

Procedure

Canine α1-PI was purified by use of ammonium sulfate precipitation, ion-exchange chromatography, and 3 affinity chromatographic procedures: concanavalin A-Sepharose, thiol, and hemoglobin-Sepharose. Characterization was performed by gel electrophoresis, isoelectric focusing, and immunoblot analysis. The N-terminal amino acid sequence was obtained by use of the Edman degradation method and a gas amino acid sequencer.

Results

Canine α1-PI was purified with a yield of approximately 7% and a 54-fold increase in specific inhibitory activity. The inhibitor had a molecular weight of 59,000 and had 2 major patterns after isoelectric focusing: fast and intermediate in homozygous and/or heterozygous forms. Edman degradation revealed glutamic acid as the starting amino acid from the N-terminal sequence. Homologies of the N-terminal sequence of canine α1-PI with those of sheep, horse, and human α1-protease inhibitors were 54, 46, and 41 %, respectively.

Conclusions

Canine protease inhibitor is analogous to the α1-protease inhibitors of sheep, human beings, and mice in terms of molecular weight, amino acid composition, and inhibitory activity against trypsin. Although the method described had a yield of 7%, the final product retained inhibitory activity and was pure.

Clinical Relevance

The availability of pure canine α1-PI, as well as the specific antibodies, will facilitate studies on the fecal excretion and structural heterogeneity of this protein in dogs with naturally acquired protein-losing enteropathy.(Am J Vet Res 1996; 57:258-263)
Detection of Toxoplasma gondii in feline and canine biological samples by use of the polymerase chain reaction
Authors: Stiles Jean , Prade Rolf , Greene Craig
Published: January 2024

Objective

To develop a polymerase chain reaction (PCR) technique to identify Toxoplasma gondii DNA in biological samples from cats and dogs.

Design

To artificially create samples that would mimic those acquired in a clinical setting from animals with naturally acquired toxoplasmosis. Using these samples, a PCR test to identify T gondii DNA was developed.

Sample Population

Feline and canine aqueous humor, CSF, serum, and blood samples.

Procedure

Tachyzoites of several strains of T gondii grown in cell culture were added to feline and canine aqueous humor, CSF, serum, and blood samples. Protocols for identifying T gondii DNA by use of the PCR were developed.

Results

The DNA from as few as 10 tachyzoites of T gondii could be identified in feline and canine aqueous humor, CSF, and serum samples. One hundred tachyzoites could be identified in blood samples.

Conclusions

Toxoplasma gondii can be identified in feline and canine biological samples by use of the PCR.

Clinical Relevance

Correlation of clinical disease to T gondii serum antibodies provides only a presumptive diagnosis of toxoplasmosis. Use of PCR to detect T gondii DNA in biological samples from cats and dogs may provide a sensitive tool for the antemortem diagnosis of toxoplasmosis and may be most beneficial when used in conjunction with serum antibody titers.(Am J Vet Res 1996;57:264-267)
Effects of intramuscular or interpleural administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy
Authors: Dhokarikar Pradnya , Caywood Dennis D. , Stobie Daniel , Raffe Marc R. , Albrecht Mark , BVSc Mathur Kannan , King Vickie , Hegstad Becky , Randall Debbie
Published: January 2024

Objective

To evaluate effects of interpleural or IM administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy.

Design

Experimental trial.

Animals

18 healthy dogs.

Procedure

Dogs underwent median sternotomy and were randomly assigned to groups of 6 dogs each. Group-A dogs were given morphine (1.0 mg/kg of body weight) IM; group-B dogs were given 0.5% bupivacaine (1.5 mg/kg) interpleurally; and group-C dogs were given morphine (1.0 mg/kg) interpleurally. Heart rate; systolic, diastolic, and mean arterial pressures; rectal temperature; pain score; and arterial blood gas partial pressures were measured and pulmonary function testing was performed immediately after extubation (time 0) and up to 48 hours later. Serum cortisol and morphine concentrations were measured at time 0 and up to 12 hours after surgery.

Results

There was a significant decrease in pH, Pao2, mean oxygen saturation of hemoglobin, and dynamic compliance; and a significant increase in Paco2. alveolar-arterial difference in partial pressure of oxygen, pulmonary resistance, and work of breathing for dogs in all groups after surgery. Serum cortisol concentrations were significantly increased, compared with preoperative values, in all dogs. Serum cortisol concentrations were significantly higher in group-B dogs between 3 and 5 hours after surgery, compared with group-A dogs.

Conclusions

Median sternotomy was associated with significant alterations in pulmonary function. Effects of interpleural administration of bupivacaine and morphine were similar to effects of IM administration of morphine.(Am J Vet Res 1996;57:375-380)
Penetration of enrofloxacin and ciprofloxacin into breast milk, and pharmacokinetics of the drugs in lactating rabbits and neonatal offspring
Authors: Aramayona Jose J. , Mora Jaume , Fraile Lorenzo J. , Garcia Maria A. , Abadía Ana R. , Bregante Miguel A.
Published: January 2024

Objective

To determine the pharmacokinetics and milk penetration of enrofloxacin (ENR) and ciprofloxacin (CIP) in lactating rabbits and their disposition in suckling rabbits.

Design

Prospective cross-over study.

Animals

6 lactating New Zealand White rabbits and their offspring (16 days after parturition).

Procedure

Serial plasma and milk samples were assayed by use of a high-performance liquid chromatography technique. In vitro protein binding in plasma and skim milk was measured by ultrafiltration. Skim-to-whole milk ratio also was determined. The time course of ENR and CIP was fitted by nonlinear least squares regression analysis, and the pharmacokinetic variables were compared.

Results

The time courses of ENR and CIP in plasma were similar in lactating adult rabbits (mean body clearances, 23.9 and 27.2 ml/min/kg of body weight, for ENR and CIP, respectively). Observed milk-to-plasma ratios (M/P) were determined, using the area under the milk and plasma concentration versus time profiles (ENR, 2.59; CIP, 3.61). Predicted M/P (ENR, 6.35; CIP, 3.04) were calculated from in vitro measurements. Body clearance calculated for ENR and CIP in suckling rabbit pups involved a decrease of 80 and 74%, respectively, over that found in lactating animals.

Conclusions

Observed CIP M/P were correlated to predicted values, which strengthens the argument that CIP passes into the milk by nonionic diffusion. The lack of correlation between observed and predicted ENR M/P pointed out that ENR undergoes faster elimination from milk than that predicted by the diffusional model. Diminished elimination capacity observed in suckling rabbits would result in greater exposure than that predicted from concentrations alone. (Am J Vet Res 1996;57:547–553)
Contribution of passive immunity to porcine respiratory coronavirus to protection against transmissible gastroenteritis virus challenge exposure in suckling pigs
Authors: Sestak Karol , Lanza Ignacio , Park Seong-Kuk , Weilnau Peggy A. , Saif Linda J.
Published: January 2024

Objective

To determine the ability of porcine respiratory coronavirus (PRCV) infections to induce passive immunity in suckling pigs to transmissible gastroenteritis virus (TGEV) challenge exposure.

Design and Animals

4 TGEV seronegative sows and their litters (group A) served as controls, whereas 2 other groups (B and C) of sows (also TGEV seronegative) were oronasally inoculated with live PRCV during 1 or 2 subsequent pregnancies, respectively.

Procedure

Effectiveness of passive immunity provided to pigs via colostrum and milk was assessed after TGEV challenge exposure, and TGEV antibody responses in colostrum and milk were analyzed.

Results

Mortality in the 3 groups of young pigs correlated with severity of clinical signs of TGEV infection and was highest in control litters (86% in group-A pigs) and lowest in litters of sows inoculated with PRCV in 2 subsequent pregnancies (14% in group-C pigs). Virus-neutralization and IgA and IgG TGEV antibody titers of milk collected from sows at challenge exposure had significant positive correlation with litter survival. Significantly higher numbers of TGEV-specific IgA and IgG antibody-secreting cells were found in group-A pigs than in group-C pigs, suggesting that high titer of maternal antibodies (induced in group-C sows multiply exposed to PRCV) may interfere with active antibody responses.

Conclusions and Clinical Relevance

Results suggest that, in PRCV-infected pig herds, multiple exposures of pregnant sows are associated with higher IgA and IgG antibody titers to TGEV in milk, and these titers contribute to protection against TGEV infection. (Am J Vet Res 1996; 57:664–671)
Effects of rate of gain on scrotal circumference and histopathologic features of the testes of half-sibling yearling beef bulls
Authors: Ohl M. W. , Ott R. S. , Faulkner D. B. , Hornbuckle T. , Hess R. A. , Cmarik G. F. , Zinn G. M.
Published: January 2024

Objective

To determine the effects of high and low gain on production variables and reproductive characteristics of bulls, including histopathologic lesions in the testes, as determined by quantitative measurements.

Animals

23 half-sibling, 11.6-month-old beef bulls, averaging 326 ± 8.3 kg in weight and having a mean scrotal circumference of 28.7 ± 0.4 cm.

Design

Bulls were randomly assigned within pairs to high- or low-gain rations and fed ad libitum for 112 days.

Procedures

Scrotal circumference and body weight were measured on days 0, 28, 56, 84, and 112. Bulls were castrated on day 112. Morphologic characteristics of spermatozoa were determined from samples taken on days 50 and 111. Testis sections from each bull were examined, using light microscopy, for changes in the seminiferous epithelium and interstitium. A grading scheme was used to quantify testicular lesions by histologic techniques. Pathologic changes in 600 cross sections from each bull were classified into 9 grades. The degree of germinal epithelial loss per 100 tubules was calculated by assigning a value to each grade according to the severity of loss of germinal epithelium.

Results

Scrotal circumference (mean ± SEM cm), 34.0 ± 0.8 vs 31.7 ± 0.5 (P < 0.001), body weight (kg), 512.3 ± 19.6 vs 421.9 ± 9.4 (P < 0.001), and paired testicular and epididymal weight (g), 532 ± 31 vs 425 ± 24 (P < 0.0001) and 73.8 ± 1.9 vs 56.3 ± 3.7 (P < 0.001) were greater in the high-gain than in the low-gain group. Morphologic characteristics of spermatozoa were similar for both groups. Means for graded seminiferous epithelial effects were similar in each group. Hypoplastictype tubules were found in bulls with small scrotal circumference in both the high- and low-gain groups.

Conclusion

High gain resulted in greater testicular growth but testicular structure and function were similar for both groups. (Am J Vet Res 1996;57:844–847)
Effects of pretreatment with ketoprofen and phenylbutazone on experimentally induced synovitis in horses
Authors: Owens Jane G. , Kamerling Steven G. , Stanton Shawn R. , Keowen Michael L. , Prescott-Mathews Judith S.
Published: January 2024

Objective

To compare the analgesic and anti-inflammatory effects of the nonsteroidal anti-inflammatory drugs (NSAID), ketoprofen (2.20 and 3.63 mg/kg of body weight) and phenylbutazone (4.40 mg/kg), in an acute equine synovitis model.

Design

4 groups of 6 horses received NSAID or saline solution in a randomized design.

Animals

24 clinically normal mares and geldings.

Procedure

Left intercarpal joints were injected with sterile carrageenan to induce synovitis at the same time as IV administration of NSAID or saline solution. Clinical assessments were made and synovial fluid was withdrawn at 0, 1, 3, 6, 9, 12, 24, and 48 hours.

Results

The eicosanoids, prostaglandin E2 (PGE2) and leukotriene B4, increased in synovial fluid after synovitis induction in all horses then returned to near baseline by 48 hours. All NSAID-treated horses had decreased PGE2, compared with saline-treated horses. This effect lasted longer in phenylbutazone-treated horses than in ketoprofen-treated horses. There were no treatment effects on leukotriene B4. In saline-treated animals, lameness, joint temperature, and synovial fluid volume, protein concentration, and nucleated cells increased 3 to 12 hours after induction, with marked reduction by 48 hours. Only phenylbutazone treatment reduced lameness, joint temperature, and synovial fluid volume.

Conclusion

Phenylbutazone was more effective than ketoprofen in reducing lameness, joint temperature, synovial fluid volume, and synovial fluid PGE2. Results do not support lipoxygenase inhibition by either NSAID.

Clinical Relevance

This reversible model induced synovial fluid alterations similar to those observed in horses with septic arthritis. Results indicate that phenylbutazone may be more useful than ketoprofen in treating acute joint inflammation. (Am J Vet Res 1996;57:866–874)
Pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin after intravenous and intramuscular administrations in sheep
Authors: Mengozzi G. , Intorre L. , Bertini S. , Soldani G.
Published: January 2024

Objective

To evaluate the pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin after administrations of enrofloxacin in sheep.

Design

Crossover study performed by IV and IM administrations of 2.5 mg of enrofloxacin/kg of body weight to 2 groups of 3 sheep. After a 15-day resting period, the drug administration was repeated, using the alternative route.

Animals

6 clinically normal Massese sheep of either sex.

Procedure

Blood samples were collected at suitable intervals over a 24-hour period, and plasma concentrations of enrofloxacin and its main metabolite ciprofloxacin were determined by a high-performance liquid chromatography method. Pharmacokinetic variables for both substances after IV and IM enrofloxacin administrations were calculated by use of statistical moments and were analyzed, using a crossover ANOVA.

Results

After IV administration of enrofloxacin, a rapid distribution phase was followed by a slower elimination phase. When the same dose was administered IM, enrofloxacin was rapidly and almost completely absorbed, with bioavailability of 85%. After 24 hours, the mean plasma concentration of ciprofloxacin was similar to that of the parent drug.

Conclusions

The large volume of distribution indicates that enrofloxacin is widely distributed in the body of sheep. The fraction of enrofloxacin metabolized to ciprofloxacin (35 and 55% for IV and IM administrations, respectively) suggests that, in this species, the antimicrobial activity of enrofloxacin could be attributable, at least in part, to its mam metabolite ciprofloxacin.

Clinical Relevance

IV or IM administration of 2.5 mg of enrofloxacin/kg provides plasma concentrations higher than mean inhibitory concentration for most pathogens in sheep. (Am J Vet Res 1996;57:1040–1043)
Nephrotoxicity of amphotericin B administered to dogs in a fat emulsion versus five percent dextrose solution
Authors: Randall Stacy R. , Adams Larry G. , White M. Randall , DeNicola Dennis B.
Published: January 2024

Objective

To determine whether administration of amphotericin B in a fat emulsion solution would reduce the nephrotoxicity of amphotericin B, compared with that associated with administration of amphotericin B in 5% dextrose solution.

Design

Prospective controlled study.

Animals

2 groups of 5 adult male Beagles.

Procedure

Dogs received amphotericin B (1 mg/kg of body weight/d) prepared in 5% dextrose solution or in 20% fat emulsion daily for 6 doses. Serum biochemical analysis, CBC, urinalysis, and endogenous creatinine clearance were performed on days 0 and 8, 2 days after the last dose of amphotericin B. On day 8, dogs were euthanatized and gross necropsies were performed. Unbiased semiquantitative scoring of the kidneys for the degree of injury was performed by use of light microscopy.

Results

There were no significant differences in serum creatinine, urea nitrogen, or potassium concentrations, urine specific gravity, endogenous creatinine clearance, or degree of tubulo-interstitial injury between the 2 groups.

Conclusion

In this model, the degree of nephrotoxicity of amphotericin B was not significantly different for dogs receiving the drug in a fat emulsion versus its administration in 5% dextrose. (Am J Vet Res 1996;57:1054–1058)
Fibrinolytic activity in dogs after surgically induced trauma
Authors: Lanevschi Anne , Kramer John W. , Greene Stephen A. , Meyers Kenneth M.
Published: January 2024

Objective

To determine whether alterations in the fibrinolytic pathway analytes, plasminogen (PLG), tissue plasminogen activator, and α2-antiplasmin are significant in dogs subjected to minor and major surgical trauma.

Animals

18 dogs in 3 groups of 6 each.

Procedure

Plasma fibrinolytic pathway analytes were measured in dogs with trauma of ovariohysterectomy (minor trauma) or orthopedic surgery (major trauma) and halothane anesthesia (control group). A commercial procedure adapted to a microtitration plate was used to measure the analytes. Blood was obtained 24 hours before anesthesia, at extubation (0 hours), and again at 2, 24, and 48 hours after extubation. An analyte quality-control strategy was maintained.

Results

In the major trauma group, there was a significant, transient, postsurgical decrease in PLG activity at 0 and 24 hours and a return to presurgical values by 48 hours. The minor trauma group had a similar trend without significant changes, including an increase in PLG values at 48 hours that exceeded the reference range. Antiplasmin values changed significantly in the major trauma group only. Tissue plasminogen activator values remained within the reference range.

Conclusions

Tissue plasminogen activator was not considered a clinical marker of interest for detection of alterations in fibrinolysis after trauma. In contrast, plasma PLG and α2-antiplasmin values may be useful in the evaluation of hemostatic complications of surgery.

Clinical Relevance

Identification of altered fibrinolysis in dogs undergoing traumatic surgery may provide a baseline for preventive pre- and postsurgical hemostatic care. (Am J Vet Res 1996;57:1137-1140)
Efficacy of a subcutaneously administered, ultraviolet light-killed Pasteurella haemolytica A1-containing vaccine against transthoracic challenge exposure in goats
Authors: Purdy Charles W. , Straus David C. , Sutherland R. J. , Ayres J. R.
Published: January 2024

Objective

To determine the effectiveness of Pasteurella haemolytica biovar A, serovar 1 (Ph A1) killed by UV light and incorporated with an oil adjuvant or carriers.

Animals

40 weanling male Spanish goats.

Procedure

Goats were randomly allotted to 1 of 6 treatment groups: 4 Ph A1 bacterins (agar beads, polyacrylate beads [PA], phosphate-buffered saline solution, Freund's incomplete adjuvant), live Ph A1 with polyacrylate beads (LiPhPA), and polyacrylate beads (UnVac). Each of 4 Ph A1 vaccines was administered SC twice, 21 days apart, to 1 of 4 groups; another group received only PA beads SC, and the last group received live Ph A1 with PA beads by transthoracic injection into the left lung. 14 days after the second vaccination, all goats were challenge exposed with live Ph A1 by transthoracic injection into the right lung, and 4 days later, all goats were euthanatized and necropsied.

Results

Mean volume of consolidated right lung tissue was 1.02 cm3 for the LiPhPA group, 168.1 cm3 for the UnVac group, 2.3 cm3 for the Freund's incomplete adjuvant bacterin group, 5.53 cm3 for the PA bacterin group, 9.01 cm3 for the agar beads bacterin group, and 7.51 cm3 for the phosphate-buffered saline solution bacterin group. Mean volume of consolidated lung tissue was significantly different between the UnVac group and the other 5 groups.

Conclusion

The LiPhPA group and 4 bacterin groups developed protective immunity against live Ph A1 challenge exposure.

Clinical Relevance

An SC administered, UV light- killed Ph A1 bacterin induced protective immunity equal to that induced by virulent live Ph A1 injected into the target organ, the lung. (Am J Vet Res 1996;57:1168-1174)
Alterations in colonic arterial and venous plasma neuropeptide concentrations in horses during low-flow ischemia and reperfusion of the large colon
Authors: Moore Rustin M. , Charalambous Andreas C. , Masty Jerome
Published: January 2024

Objective

To measure colonic arterial (CA) and colonic venous (CV) plasma neuropeptide concentrations during low-flow ischemia and reperfusion of the large colon in horses.

Animals

10 adult horses.

Procedure

CA and CV plasma samples collected from anesthetized horses during experimentally induced low-flow colonic ischemia and reperfusion were assayed for vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), and substance P (SP), using radioimmunoassays. In 6 anesthetized horses, colonic ischemia (20% of baseline [BL]) was maintained for 3 hours, then blood flow was restored and monitored for 3 hours. Hemodynamic variables were monitored continuously and recorded at 30-minute intervals. CA resistance was calculated from colonic blood flow (Qcolon) and mean CA pressure values at each time. Blood was obtained from CA and CV catheters at 0, 1, 2, 3, 3.25, 3.5, 4, 5, and 6 hours; plasma VIP, CGRP, and SP concentrations were quantified, using radioimmunoassays. In 4 additional horses, VIP and CGRP were measured in CA and CV blood at 0, 0.25, 0.5, 0.75, and 1 hour.

Results

Heart rate was significantly increased at 5.5 and 6 hours; other alterations in systemic hemodynamic variables were not significant. Decrease in Qcolon during ischemia was significant; Qcolon rebounded to a value significantly greater than BL value within 5 minutes of reperfusion and was maintained above the BL value during 3 hours of reperfusion. Mean CA pressure was significantly decreased during ischemia, but returned to a value not different from the BL value by 3.25 hours. Mean CV pressure remained unchanged from the BL value during ischemia, but increased to a value significantly greater than the BL value by 3.25 hours and remained increased through 6 hours. CA resistance began to decrease during early ischemia and was significantly less than the BL value by 3.25 hours; it remained less than the BL value through 4 hours. Increase in CV VIP concentration was significant by 0.25 hour of ischemia, but decreased to a value not different from BL value by 3.25 hours. Increase in CV CGRP was significant at 3.25 hours, but this variable returned to a value not different from BL value by 3.5 hours.

Conclusions

CV VIP concentration increases during low-flow colonic ischemia, and CV and CA CGRP and CA SP concentrations increase during early reperfusion. (Am J Vet Res 1996;57:1200-1205)
Effects of acepromazine and buprenorphine on measured indices of the signal-averaged electrocardiogram in healthy dogs
Authors: Kushner Lynne I. , Calvert Clay A. , Boyle Carolyn R.
Published: January 2024

Objectives

To determine values for indices of signal-averaged electrocardiograms (SAECG) in healthy dogs, and to determine whether sedation with acepromazine and buprenorphine would alter these indices.

Animals

15 healthy adult dogs.

Procedure

SAECG were recorded from each dog twice: prior to sedation and immediately after sedation with acepromazine (0.01 mg/kg of body weight, IV) and buprenorphine (0.007 mg/kg, IV). Time-domain methods were used to analyze the SAECG. All indices were calculated by use of a computer. Measured indices included QRS duration, duration of low-amplitude signals in the terminal part of the QRS complex, root mean square voltages of the terminal 30 and 40 milliseconds of the QRS complex, heart rate, and high-frequency noise levels.

Results

We did not detect significant differences between values measured when dogs were not sedated and values measured when dogs were sedated except in regard to heart rate (P = 0.0001) and high-frequency noise levels (P = 0.0004), which were lower when dogs were sedated. Late potentials were not visually identified in SAECG from any dog in this study.

Conclusion and Clinical Relevance

Sedation facilitated recording of SAECG in dogs without altering the results. (Am J Vet Res 1996;57:1511-1514)
Survival of Mycobacterium paratuberculosis and preservation of immunoglobulin G in bovine colostrum under experimental conditions simulating pasteurization
Authors: Meylan Mireille , Rings D. Michael , Shulaw William P. , Kowalski Joseph J. , Bech-Nielsen Steen , Hoffsis Glen F.
Published: January 2024

Objective

To determine whether Mycobacterium paratuberculosis could survive in colostrum after pasteurization. Additionally, this study investigated the effect pasteurization had on IgG concentration in colostrum.

Animals

Colostrum samples were collected from cattle (beef and dairy) owned by the state of Ohio.

Procedure

Colostrum was divided into aliquots and inoculated with variable concentrations of M paratuberculosis (ATCC No. 19698: 104, 103, and 102 colony-forming units/ml). Half the samples at each concentration were subjected to pasteurization temperatures (63 C) for 30 minutes and the remainder were kept at approximately 20 to 23 C. All samples were incubated (Herrold's egg yolk medium with and without mycobactin J) and observed for growth during the next 16 weeks. Additionally, the IgG concentration of colostrum was determined by radioimmunoassay before and after pasteurization. Samples that coagulated at pasteurization temperatures were mechanically resuspended before measurement of IgG concentration.

Results

Growth of M paratuberculosis was retarded but not eliminated by pasteurization. Growth was observed in all unpasteurized samples incubated on Herrold's egg yolk medium with mycobactin J but in only 2 of 18 pasteurized samples similarly cultured. Growth from pasteurized samples appeared 5 to 9 weeks after growth was observed from nonpasteurized samples.

Mean colostral IgG concentration was 44.4 g/L in nonpasteurized samples and 37.2 g/L in pasteurized sample, a decrease of 12.3%. High-quality colostrum (> 48 g of IgG/L) had a significantly greater loss of IgG concentration than did colostrum of lesser quality (P = 0.002).

Conclusions

Pasteurization lessened, but did not eliminate, growth of M paratuberculosis from experimentally inoculated colostrum samples. Pasteurization resulted in a significant decrease in colostral IgG concentration but not to an unmanageable level that would preclude the colostrum's use for passive transfer of immunity.

Clinical Relevance

Colostrum is macrophage rich and may serve as a source of M paratuberculosis infection to calves. Pasteurization of colostrum may lessen the risk of infection, but will not totally eliminate M paratuberculosis. (Am J Vet Res 1996;57:1580–1585)
Attempted transmission of Ehrlichia canis by Rhipicephalus sanguineus after passage in cell culture
Authors: Mathew J. S. , Ewing S. A. , Barker R. W. , Fox J. C. , Dawson J. E. , Warner C. K. , Murphy G. L. , Kocan K. M.
Published: January 2024

Objectives

To compare the transmissibility by the brown dog tick, Rhipicephalus sanguineus, of a recent isolate of Ehrlichia canis (Ebony) with that of another isolate (Oklahoma) that had been passaged in cell culture, and to assess the genetic similarity of the 2 isolates as reflected in the nucleotide (NT) sequence of 16S rDNA.

Animals

13 healthy dogs of various ages and breeds.

Procedure

Larval and nymphal ticks were acquisition fed on acutely infected dogs, and, after molting, they were transmission fed as nymphs and adults, respectively, on Ehrlichia-naive dogs. All dogs were monitored daily by blood smear evaluation for evidence of parasitized leukocytes and by physical examination for clinical signs of ehrlichiosis. Serologic and hematologic values were measured weekly. Using a nested polymerase chain reaction, the 16S rDNA was amplified, and the NT sequence of the template DNA was determined.

Results

The Ebony isolate of E canis was successfully transmitted to dogs by nymphal and adult ticks. In contrast, no ticks that fed on dogs harboring the cell-cultured isolate (Oklahoma) transmitted it to dogs. On the basis of 16S rDNA sequence, the 2 isolates were 99.9% similar, with only 1 NT difference.

Conclusions

These results reconfirm the vector potential of R sanguineus for E canis. Passage of the Oklahoma isolate of E canis in cell culture apparently adversely affected its transmissibility by ticks, raising the possibility that cell-cultured isolates of this rickettsia may lose their affinity for ticks. Determination of 16S rDNA sequence suggests minor strain variation within the species E canis. (Am J Vet Res 1996;57:1594–1598)
Abortion and placentitis in pregnant bison (Bison bison) induced by the vaccine candidate, Brucella abortus strain RB51
Authors: Palmer Mitchell V. , Olsen Steven C. , Gilsdorf Michael J. , Philo Lee M. , Clarke Patrick R. , Cheville Norman F.
Published: January 2024

Objective

To determine the ability of Brucella abortus strain RB51 to induce placentitis and abortion in bison after SC vaccination.

Animals

10 pregnant bison cows, 3 to 10 years old and at 3 to 8 months' gestation.

Procedure

Pregnant bison cows on a Montana ranch were vaccinated SC with 109 colony-forming units of B abortus strain RB51. Two cows, identified prior to the study, were euthanatized and examined 5 weeks after vaccination to obtain optimal histologic samples of placenta. Other cows were euthanatized and examined after abortion. After euthanasia, tissue specimens were collected for histologic and immunohistochemical evaluation. Tissue and fluid specimens for bacteriologic culture were also collected during necropsy.

Results

Of 8 cows, 2 aborted at 68 and 107 days after vaccination. Aborting cows had endometritis. Strain RB51 was isolated from reproductive tissues and supramammary lymph nodes. Fetal lesions were not seen; however, fetal bronchial lymph nodes and amniotic fluid contained strain RB51. Cows examined 5 weeks after vaccination had placentitis and endometritis, with numerous bacteria within trophoblastic epithelial cells that were immunoreactive for strain RB51 antigen. Strain RB51 was isolated from placentomes and numerous lymph nodes. Fetal lesions were not seen 5 weeks after vaccination; however, strain RB51 was isolated from numerous lymph nodes and lung, allantoic fluid, and rectal swab specimens.

Conclusions

The vaccine candidate B abortus RB51 has tropism for the bison placenta, and can cause placentitis, which induces abortion in pregnant bison. The vaccine dose used was similar to that being tested in cattle, but may not be appropriate for pregnant bison. (Am J Vet Res 1996;57:1604–1607)
Effects of naturally acquired decompensated mitral valve regurgitation on the renin-angiotensin-aldosterone system and atrial natriuretic peptide concentration in dogs
Authors: Häggström Jens , Hansson Kerstin , Kvart Clarence , Karlberg Bengt E. , Vuolteenaho Olli , Olsson Kerstin
Published: January 2024

Objective

To investigate activity of the renin-angiotensin-aldosterone system and N-terminal pro-atrial natriuretic peptide (NT-proANP) during development of clinical signs of decompensated mitral valve regurgitation (MR).

Animals

11 Cavalier King Charles Spaniels with advanced MR attributable to chronic valvular disease.

Procedure

Dogs were subjected to repeated examinations at 6-month intervals until signs of decompensation had developed (end point). Data acquired at end point were compared with data obtained from examinations 1 year and 1 to 6 months before decompensation. Each examination included physical examination, collection of venous blood, thoracic radiography, and echocardiography.

Results

Echocardiography measurements of left atrial-to-aortic root ratio and left ventricular end diastolic diameter increased considerably during the study, whereas left ventricular end systolic diameter remained unchanged. The increase in cardiac size was associated with increased plasma concentration of NT-proANP. In contrast, plasma concentrations of aldosterone and angiotensin II were reduced at decompensation (aldosterone compared with the 2 earlier examinations and angiotensin II compared with values obtained 1 to 6 months before), despite decreased plasma protein concentration and hematocrit, suggesting fluid retention. The urine-to-plasma creatinine ratio was reduced at end point.

Conclusion and Clinical Implications

Early decompensated MR in dogs was not associated with increased circulating renin-angiotensin-aldosterone system activity, which may be caused by increased activity of ANP, and may be important for future therapeutic strategies of MR. (Am J Vet Res 1997;58:77–82)
Optimization of prothrombin time measurements in canine plasma
Authors: Mischke Reinhard , Nolte Ingo
Published: January 2024

Objective

To optimize a prothrombin time (PT) method designed for human plasma for use with canine plasma.

Sample Population

100 plasma samples from healthy dogs and 50 plasma samples with reduced activity of the single factors II, V, VII or X.

Procedure

Canine plasma samples with various coagulation activity values (100, 75, 50, 25 and 10%: prepared by dilution from a plasma pool [n = 100]) were assayed at various sample dilutions and dilutions of the thromboplastin component of 3 commercial calcium thromboplastin reagents. The so-named optimized PT test was compared with the standard test with respect to its sensitivity and correlation with the sum of the activity decreases of single factors II, V, VII, and X in relation to the respective reference range.

Results

The time intervals between various coagulation activity values, which were small by use of the standard test, could be increased by diluting the sample and substituting fibrinogen, but not by diluting the tissue thromboplastin component of PT reagent. On the basis of 50 abnormal plasma samples, the optimized test had high sensitivity (0.90 to 1.00, dependent on reagent and sample dilution) in contrast to the standard test, which had low sensitivity (0.24 to 0.58, dependent on reagent). Also, correlation with the sum of the activity decreases was closer by use of the optimized (0.90 to 0.93) than the standard (0.58 to 0.84) test.

Conclusions

In contrast to the standard test, an optimized test is suitable as a sensitive screening test of the extrinsic coagulation system in dogs.

Clinical Relevance

The optimized PT method is easy to perform and, therefore, should be in general use for assay of canine plasma. (Am J Vet Res 1997; 58:236–241)
Stability of γ-glutamyltransferase activity in calf sera after refrigerated or frozen storage
Authors: Muller Fred , Tyler Jeff W. , Parish Steven M. , Johnson Kristen A. , Krytenberg Denise S. , Wilson Leilani K.
Published: January 2024

Objectives

To examine stability of -glutamyltransferase (GGT) activity in stored serum from neonatal calves.

Animals

10 commercial beef calves between 36 and 60 hours old.

Procedure

Serum samples were obtained from the calves, and each sample was divided into 8 aliquots. Serum GGT activity was measured on day 0 (fresh) and days 1, 2, 3, and 4 of refrigerated storage (4 C) and weeks 1, 2, and 3 of frozen storage (−20 C).

Results

Serum GGT activities for each of the refrigerated aliquots did not significantly differ from day zero, with serum GGT activity (expressed as a percentage of initial activity) > 99% on all 4 days. Serum GGT activity in frozen aliquots decreased significantly after 1 and 2 weeks of frozen storage, 97 and 98%, respectively; however, this decrease in GGT activity was not biologically significant. The observed GGT activity did not decrease significantly in the samples stored frozen for 3 weeks; these samples retained 99% of initial activity.

Conclusion

The observed stability of serum GGT activity indicates that serum may be obtained, stored, and batch processed at a later time. This stability during storage is important to the success of a bovine passive transfer monitoring program based on GGT activity. (Am J Vet Res 1997;58:354-355)