bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of arsenical drugs on in vitro vascular responses of pulmonary artery from heartworm-infected dogs
Authors: Maksimowich Daria S. , Bell Thomas G. , Williams Jeffrey F. , Kaiser Lana
Published: January 2024

Objective

To test the effect of thiacetarsamide and melarsomine on vascular responses in isolated rings of pulmonary artery from heartworm-infected dogs.

Animals

18 heartworm-infected dogs.

Procedure

Isolated rings of pulmonary artery from heartworm-infected dogs were randomly treated with thiacetarsamide (30 μg/ml) or melarsomine dihydrochloride (30 μg/ml) for 30 minutes; untreated rings from the same dog served as control. Cumulative dose-response relations to norepinephrine, nitroglycerin, and methacholine were determined.

Results

Norepinephrine-induced constriction was not altered by treatment with either thiacetarsamide or melarsomine. Treatment with thiacetarsamide depressed nitroglycerin-induced relaxation, compared with values for untreated control rings and rings treated with melarsomine. Treatment of rings with thiacetarsamide or melarsomine depressed methacholine-induced relaxation, compared with values for untreated rings. Histologic examination of rings indicated that treatment with thiacetarsamide or melarsomine resulted in loss of endothelial cells.

Conclusion

Endothelial cell loss as a direct drug effect may be responsible for impaired endothelium-dependent relaxation in pulmonary artery from heart-worm-infected dogs. Thiacetarsamide appears to have additional effects on vascular smooth muscle, which may explain why fewer complications are observed in dogs treated with melarsomine.

Clinical Relevance

Melarsomine may be a safer drug than thiacetarsamide and could be a better treatment for dogs with heartworm infection. (Am J Vet Res 1997;58:389–393)
Pharmacokinetics of propranolol in healthy cats during euthyroid and hyperthyroid states
Authors: Jacobs Gilbert , Whittem Ted , Sams Richard , Calvert Clay , Ferguson Duncan
Published: January 2024

Objective

To examine the pharmacokinetic profile of propranolol in cats before and during experimentally induced hyperthyroidism.

Animals

8 conditioned, random-source, young adult, female cats.

Procedure

Propranolol was administered IV as a single bolus and 72 hours later by mouth. Thereafter, the cats were dosed for 5 weeks with L-thyroxine (50 μg/kg of body weight, SC, once daily) to induce hyperthyroidism (serum thyroxine concentration, 217 ± 17 nmol/L). Blood samples were obtained at appropriate intervals before and during hyperthyroidism and were analyzed for plasma propranolol concentration by use of high-performance liquid chromatography.

Results

In all cats, a two-compartment model best described the control and hyperthyroid intravenous data. The change in thyroid status from euthyroid to hyperthyroid caused a significant (P < 0.05), but small reduction in propranolol area under the curve (19,932 ± 7,900 min·μg/L vs 15,911 ± 1,400 min · μg/L) after IV administration. In contrast, after oral administration during the hyperthyroid state, a twofold increase (P < 0.05) in propranolol area under the curve (105,430 ± 57,600 min·μg/L vs 226,811 ± 112,000 min·μg/L) and peak serum propranolol concentration (651 ± 247 μg/L vs 1191 ± 590 μg/L) were attributed to significant (P < 0.05) increase in propranolol bioavailability caused by increased fractional absorption (57 ± 28% vs 137 ± 73%) and decreased total body clearance (58 ± 27 ml/min/kg vs 30 ± 19 ml/min/kg). Mean arrival time after oral dosing was significantly lengthened by hyperthyroidism (100 ± 38 minutes vs 157 ± 71 minutes).

Clinical Relevance

Hyperthyroidism-induced changes in propranolol pharmacokinetics may signal the need to reduce doses of propranolol when they are orally administered to hyperthyroid cats. (Am J Vet Res 1997;58:398–403)
Diversity of Streptococcus agalactiae and Staphylococcus aureus ribotypes recovered from New York dairy herds
Authors: Rivas Ariel L. , González Rubén N. , Wiedmann Martin , Bruce James L. , Cole Eileen M. , Bennett Gary J. , Schulte Hal F. , Wilson David J. , Mohammed Hussni O. , Batt Carl A.
Published: January 2024

Objectives

To develop a reference database for characterization of bovine Staphylococcus aureus and Streptococcus agalactiae strains by automated ribotyping and to use it to assess the discriminatory power of this typing procedure and the geographic distribution of Sta aureus and Str agalactiae strains in New York state dairy herds.

Sample Population

22 commercial dairy herds.

Procedure

Isolates of Sta aureus and Str agalactiae from bovine milk were identified by standard bacteriologic procedures, then typed by automated ribotyping. Antimicrobial susceptibility of isolates was tested in vitro. Two indicators made from the data were percentage of farms with multiple ribotypes and percentage of single ribotypes found in several geographic regions. Standard bacteriologic diagnosis, automated ribotyping, and determination of antibiograms (Kirby-Bauer method) also were done.

Results

Of 50 Sta aureus and 44 Str agalactiae isolates from composite milk samples of 12 and 10 herds, respectively, 18 and 14 ribotypes, respectively, were identified. The discriminatory power of automated ribotyping was approximately 0.96 (Hunter-Gaston's formula). A higher percentage of herds with Sta aureus had multiple ribotypes. The most common Sta aureus ribotypes tended to have broader geographic distribution. Some Sta aureus ribotypes were significantly associated with antibiotic resistance profiles.

Conclusions

Automated ribotyping appears to characterize bovine strains of bacteria associated with intramammary infections with a high discriminatory index. Potential applications include identification of strains that appear to have broad geographic distribution suggesting interfarm transfer, discrimination between recurrent versus new intramammary infections (ie, for control of Str agalactiae and Sta aureus), and evaluation of antibiotic therapy. (Am J Vet Res 1997;58:482–487)
Identification of β-adrenergic receptor subtypes mediating relaxation in isolated equine ileum
Authors: Re Giovanni , Belloli Chiara , Badino Paola , Arioli Francesco , Novelli Antonella , Girardi Carlo , Beretta Carlo
Published: January 2024

Objective

To identify β-adrenergic receptor subtypes in ileum smooth muscle of the horse.

Sample Population

Isolated strips of equine longitudinal ileum smooth muscle and membrane preparations from smooth muscle of the intestinal wall.

Procedure

Functional assays and radioligand binding assays.

Results

Relaxation of ileum longitudinal smooth muscle proved to be mainly caused by stimulation of β-atypical and β2-adrenergic receptors. Binding studies on cell membranes indicated that the total β-adrenergic receptors population consists of 54% β-atypical, 34% β2-, and 12% β1-subtypes.

Conclusions

The data suggest that sympathetic relaxation of equine ileum smooth muscle depends mainly on β-atypical receptor subtypes activation, with a minor contribution by β2-subtypes.

Clinical Relevance

The important role of β-atypical adrenergic receptor subtypes in the relaxation of equine ileum suggests possible clinical use of selective β-atypical receptor agonists to control intestinal disturbances. (Am J Vet Res 1997;58:621–625)
Pharmacokinetics of phenylbutazone in camels
Authors: Wasfi Ibrahim Abdel Rahman , Hadi Abdel Hadi Ahmed Abdel , Zorob Omer , Osman Mohamed AlGhazali , Boni Nader Santo
Published: January 2024

Objective

To document disposition variables of phenylbutazone and its metabolite, oxyphenbutazone, in camels (Camelus dromedarius) after single IV bolus administration of phenylbutazone, with a view to making recommendation on avoiding violative residues in racing camels.

Animals

6 healthy camels (4 males, 2 females), 5 to 7 years old, and weighing from 350 to 450 kg.

Procedure

Blood samples were collected at 0, 5, 10, 15, 45, and 60 minutes and at 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 8, 12, 24, 26, 28, 30, 40, 48, 50, 53, and 60 hours after IV administration of 4.5 mg of phenylbutazone per kg of body weight. Urine was obtained in fractions during the entire blood sample collection period. Serum and urine phenylbutazone concentrations were measured by high-performance liquid chromatography; assay sensitivity was 100 ng/ml. Serum oxyphenbutazone concentration was measured by gas chromatography/mass spectrometry; assay sensitivity was 10 ng/ml.

Results

Disposition of phenylbutazone was best described by a two-compartment open model. Mean ± SEM elimination half-life was 13.44 ± 0.44 hours. Total body clearance was 12.63 ± 1.64 mg/kg/h. Renal clearance was between 0.3 and 0.4% of total body clearance. The elimination half-life of oxyphenbutazone was 23.9 ± 2.09 hours.

Conclusions

The elimination half-life and total body clearance of phenylbutazone in camels are intermediate between reported values in horses and cattle. Extrapolation of a dosage regimen from either species to camels is, therefore, not appropriate. Elimination of phenylbutazone in camels is mainly via metabolism. Owing to the long half-life of phenylbutazone and of oxyphenbutazone, and to the zero drug concentration regulation adopted by the racing commissioner in the United Arab Emirates, practicing veterinarians would be advised not to use phenylbutazone in camels for at least 7 days prior to racing. (Am J Vet Res 1997;58:636–640)
Effects of sedation, anesthesia, and endotracheal intubation on respiratory mechanics in adult horses
Authors: Tomasic Michael , Mann Lori S. , Soma Lawrence R.
Published: January 2024

Objective

To determine the effects of endotracheal intubation on respiratory mechanics during xylazine sedation and xylazine-diazepam-ketamine anesthesia in adult horses.

Animals

5 healthy adult horses.

Procedure

Measurements were derived from recordings of respiratory gas flow, and transpulmonary and transtracheal pressures. Total pulmonary resistance (RT) was partitioned into upper airway resistance (extrathoracic portion of trachea, larynx, pharynx, nasal cavity, nares; RUA) and lower airway resistance (intrathoracic portion of trachea, bronchi, bronchioles). Baseline measurements were obtained in unsedated horses, after xylazine administration, and following nasotracheal intubation (ID, 18 mm). Measurements were obtained following induction of xylazine-diazepam-ketamine anesthesia and subsequent to endotracheal intubations (ID, 22, 20, and 16 mm). During recovery, horses were nasotracheally intubated (ID, 18 mm). Measurements were obtained upon standing, and repeated after extubation. Data were examined by use of ANOVA with repeated measures.

Results

Significant increases in mean work of breathing (W), RT, and RUA observed with xylazine sedation were variably attenuated by nasotracheal intubation. During xylazine-diazepam-ketamine anesthesia, the highest mean values for W, RT, RUA, transpulmonary and transtracheal pressures developed during nonintubation periods. The magnitudes of resistance and pressure values were inversely proportional to the internal diameter of the endotracheal tube. At recovery, values of the W and all measurements of resistances and pressures were significantly increased, compared with presedation values. Extubation resulted in further increases in these measurements.

Conclusions

Work of breathing in horses is substantially increased when RUA is increased during xylazine sedation and xylazine-diazepam-ketamine anesthesia. Endotracheal intubation reduces W by reducing RUA. (Am J Vet Res 1997;58:641–646)
Effects of halothane and sevoflurane on the electroretinogram of dogs
Authors: Yanase Jun , Ogawa Hiroyuki
Published: January 2024

Objective

To study the effects of halothane and sevoflurane on the electroretinogram of dogs.

Animals

6 clinically normal Beagles.

Procedure

Beagles were paralyzed by continuous IV administration of muscle relaxant and were artificially ventilated with a gas mixture of nitrous oxide and oxygen during experiments. Corneal electroretinograms were recorded, using full-field stimuli under several recording conditions before and during 1 % halothane or 2% sevoflurane inhalation.

Results

The amplitude of the scotopic threshold response (STR) and b-wave was significantly decreased by halothane or sevoflurane inhalation, but the degree of decrease in the STR was much greater. In contrast, the amplitudes of oscillatory potentials were increased. The peak latencies of the 3 components tended to be prolonged by inhalation of the anesthetic. There seemed to be no difference between the effects of halothane and sevoflurane.

Conclusions

Halothane and sevoflurane strongly depressed the STR in Beagles while moderately depressing the b-wave and increasing oscillatory potential amplitudes. Thus, neither is an appropriate anesthetic for use in recording of the STR in dogs. (Am J Vet Res 1997;58:904–909)
Evaluation of the catabolic activity of cartilage by measurement of serum keratan sulfate concentration in foals
Authors: Okumura Masahiro , Fujinaga Toru , Urakawa Etsuko , Tagami Masaaki , Tsukiyama Katsuji
Published: January 2024

Objectives

To determine keratan sulfate (KS) concentration in the serum of foals at the early stage of growing, and to evaluate the role of serum KS as a cartilage catabolic marker, comparing its values with the fluctuation of serum alkaline phosphatase (ALP) activity as a measurement of osteoblastic activity.

Animals

12 foals with normal growth and 3 foals with joint abnormalities within 18 months after birth.

Procedure

Measurement of KS concentration and ALP activity in serum and radiographic and physical examinations were done.

Results

In all foals, serum KS concentration was high from 1 week after birth to 3 months of age, while serum ALP decreased with aging. The value started to decrease rapidly from 3 to 5 months of age, then gradually reached adult values. During the first 3 months, KS concentration in male foals was significantly higher than that in female foals. In 3 foals which had joint problems, KS concentration was higher than that in normally growing foals at 1 week, and at 1, 2, and 3 months of age.

Conclusions

Cartilage catabolic activity is higher in developing foals up to 3 months of age, suggesting that the immature joint at this time could be easily affected by any factor of loading. Moreover, though only 3 diseased foals were examined, higher serum KS concentration in these foals suggest that this variable might be a useful measure of joint diseases, even at an early stage of life in foals. (Am J Vet Res 1997;58:925–929)
Evaluation of noninvasive monitoring techniques in domestic ferrets (Mustela putorius furo)
Authors: Olin Jane M. , Smith Tracy J. , Talcott Michael R.
Published: January 2024

Objective

To evaluate instrument placement and accuracy of indirect physiologic monitoring techniques in anesthetized domestic ferrets.

Animals

10 healthy adult female ferrets (Mustela putorius furo).

Procedure

Direct arterial blood pressure measurement and arterial blood sample collection were performed in ferrets. A pulse oximeter probe was clipped to a forefoot or hind foot; an airway adaptor for capnography was attached to the endotracheal tube; and a sphygmomanometer cuff and Doppler flow probe were positioned on the tail. Isoflurane and nitrous oxide concentrations were varied to induce episodes of hypotension or hypoxia, respectively. Aforementioned noninvasive techniques were compared with direct methods of arterial blood gas analysis, hemoximetry, and arterial blood pressure measurement. Simultaneously obtained direct and indirect measurements were statistically evaluated for mean and SD of the differences, and SEM, and subjectively, for ease of use and relevance to the clinical situation.

Results

Values obtained from pulse oximetry were closely related to oxygen saturation measured by blood gas analysis (O2sat). The mean (± SD) difference for all results was −0.49 (± −4.09)%. The most precise measurements were obtained when O2sat was between 90 and 100%. Capnography measurements varied between ranges. The most accurate measurements were obtained when Paco2 was < 25 mm of Hg, when the mean difference was 1.6 (± −3.01) mm of Hg. Indirect blood pressure measurement consistently underestimated the direct blood pressure value.

Conclusions and Clinical Relevance

Pulse oximetry is a convenient and accurate method for monitoring oxygen saturation in domestic ferrets. Capnography is useful for monitoring respiratory rate and pattern, but may present difficulties in interpretation of actual Paco2. Indirect blood pressure monitoring is not accurate by use of current methods in ferrets. (Am J Vet Res 1997;58:1065–1069)
Reliability of using random urine samples for “spot” determination of fractional excretion of electrolytes in cats
Authors: Finco Delmar R. , Brown Scott Alan , Barsanti Jeanne A. , Bartges Joseph W. , Cooper Tanya A.
Published: January 2024

Objective

To determine whether the “spot” method of determining fractional excretion (FE) of electrolytes in cats is accurate.

Animals

5 clinically normal young adult female cats.

Procedure

Cats were acclimated to metabolism cages, and 2 consecutive 72-hour collections of urine were made to determine FE of total calcium, potassium, total magnesium, sodium, and phosphorus by conventional methods, using endogenous creatinine clearance as an estimate of glomerular filtration rate. During collections, small samples of urine were obtained by cystocentesis at 8 am, 3 pm, and 9 pm for determination of FE of the electrolytes by use of the “spot” method.

Results

Values from “spot” determinations were highly variable, compared with 72-hour values, with a high percentage falling outside the range of mean ± 2 SD for 72-hour FE values.

Conclusions and Clinical Relevance

The “spot” method for determining FE is not precise, and if used, caution and judgement should be exercised in interpretation of the results. (Am J Vet Res 1997;58:1184–1187)
Urine N-acetyl-β-D-glucosaminidase activity in healthy cattle
Authors: Sato Reeko , Nakajima Naoko , Soeta Satoshi , Sato Jun , Naito Yoshihisa
Published: January 2024

Objective

To measure urine N-acetyl-β-D-glucosaminidase (NAG) activity of healthy cattle, using 3 substrates (4-methylumbelliferyl-N-acetyl-β-D-glucosaminide, sodio-m-cresolsulfonphthaleinyl-N-acetyl-β-D-glucosaminide, and p-nitrophenyl-N-acetyl-β-D-glucosaminide), and to determine the relations between the obtained values and age and sex of cattle.

Animals

50 healthy lactating Holstein-Friesian cows and 10 healthy Holstein-Friesian steers.

Procedure

Untimed urine samples were collected, and urine NAG activity was measured, using the 3 aforementioned methods. Urine creatinine concentration also was measured, and NAG activity was expressed as units per gram of creatinine (NAG index). Correlations between urine NAG activity and age and sex of cattle were investigated. Furthermore, correlations among data obtained by each of the 3 methods were determined.

Results

Urine NAG activity in cows measured by each of the 3 methods was < 3.0 U/L. Urine NAG activity in steers was significantly higher than that in cows. However, there was no significant difference between the sexes in NAG index. There were no significant differences in mean values of NAG activity and index among cows of various age groups. Individual values of urine NAG activity determined by each method correlated significantly with each other.

Conclusions and Clinical Relevance

Urine NAG activity and NAG index of healthy cattle will be useful for determining diagnostic criteria of renal disease in cattle. (Am J Vet Res 1997;58:1197–1200)
Diagnosis of trichinellosis in swine by enzyme immunoassay, using a synthetic glycan antigen
Authors: Gamble H. R. , Wisnewski N. , Wasson D. L.
Published: January 2024

Objective

To assess performance of a synthetic carbohydrate antigen for use in an enzyme immunoassay for diagnosis of trichinellosis in swine.

Animals and Sample Population

47 York X Duroc pigs and field sera from 265 farm pigs raised under various management systems.

Procedures

Each of 47 pigs was inoculated with 25 to 500 Trichinella spiralis larvae, and blood samples were obtained weekly. At postinoculation week 12, pigs were euthanatized, and tissues recovered from the tongue and diaphragm were digested to determine worm burden. Serum samples from experimentally infected pigs and sera obtained from pigs on a farm were tested by enzyme immunoassay, using standard excretory-secretory and synthetic glycan antigens.

Results

Of the 47 pigs, 46 (97.8%), with worm burden ranging from 0.02 to 248.8 larvae/g of tissue in the tongue and diaphragm, tested seropositive using both antigens. Time of seroconversion varied among pigs and was negatively correlated with intensity of infection. Minor differences were observed in time of seroconversion between the 2 antigens in 11 of 46 pigs, suggesting some differences in the antibody response. One pig with a worm burden of 0.01 larva/g was not detected by enzyme immunoassay using either antigen. Background values obtained using the 2 antigens did not differ among confinement-raised pigs, but background values for pigs raised outdoors on dirt lots were significantly lower using the glycan antigen. Low-level, naturally acquired T spiralis infections in pigs were detected in most instances by use of both antigens, although there were some differences in antibody responses of infected pigs.

Conclusion

The synthetic glycan antigen has potential for replacing excretory-secretory antigens as a standardized reagent for diagnosis of trichinellosis in pigs. (Am J Vet Res 1997;58:1417–1421)
Secondary stress responses to acute handling in striped bass (Morons saxatilis) and hybrid striped bass (Morons chrysops × Morons saxatilis)
Authors: Reubush Kimberly J. , Heath Alan G.
Published: January 2024

Objective

To test the hypothesis that, compared with pure striped bass, hybrid striped bass have reduced secondary physiologic responses to handling stress. A secondary objective was to determine whether not feeding fish for a 3-day period affected responses.

Animals

Hatchery-reared adult striped bass (Morone saxatilis) and adult hybrids of striped bass with white bass (M chrysops), with mean length of 27.9 cm and mean weight of 487 g.

Procedure

Fed and 3-day nonfed fish, in groups of 6, were held in dip nets above water for 3 minutes. Severity of response to handling was determined by measuring plasma glucose and chloride and blood lactic acid, sodium, and potassium concentrations. Terminal samples were taken from fish before handling (control), immediately after handling, and after 12, 24, and 48 hours of recovery.

Results

Striped bass were hyperglycemic and lactacidemic after stress and for 12 to 48 hours afterward, whereas glucose and lactic acid values in hybrids were essentially unchanged. Blood sodium and chloride concentrations of hybrids decreased after stress, then returned to control values within 24 hours. Striped bass, however, had a greater decrease in values for these electrolytes and failed to recover in 48 hours. Blood potassium concentration remained unchanged in all test groups. Nonfeeding for 3 days before handling did not appear to affect stress response in striped bass or hybrids.

Conclusions and Clinical Relevance

Striped bass have an appreciably greater response to acute handling stresses, such as those that may be experienced in hatcheries and experimental laboratories, than do hybrid bass. Thus, pure striped bass require more care in handling. The usual practice of not feeding before handling does not affect physiologic responses. (Am J Vet Res 1997;58:1451–1456)
Frequency of supernumerary teeth in a dolichocephalic canine breed, the Greyhound
Authors: Dole Robert S. , Spurgeon Thomas L.
Published: January 2024

Objective

To determine the frequency of supernumerary teeth in Greyhounds.

Animals

55 Greyhounds obtained anonymously from a variety of breeders.

Procedure

Greyhounds were examined for the presence of supernumerary teeth.

Results

Supernumerary teeth were present in 20 of 55 (36.4%) Greyhounds surveyed.

Conclusions

Location of supernumerary teeth, usually first premolars, is not random, but favors occurrence in the upper arcade. Occurrence of supernumerary teeth did not favor the left or right side.

Clinical Relevance

Because an increasing number of veterinary anatomy textbooks use Greyhounds as typical examples, it is important to note the high frequency of supernumerary teeth. (Am J Vet Res 1998;59:16–17)
Enzyme-linked immunosorbent assay for canine α1-protease inhibitor
Authors: Melgarejo T. , Williams D. A. , Asem E. K.
Published: January 2024

Objective

To develop and validate an ELISA for quantifying α1-protease inhibitor (α1-PI) in serum and fecal extracts.

Procedure

Affinity-purified rabbit origin canine α1-PI antibodies were biotinylated and, after addition of streptavidin-horseradish peroxidase, were used as the labeled complex in a noncompetitive immunoassay. The α1-PI standards were made from purified serum canine α1-PI diluted in phosphate-buffered saline solution containing 5% newborn calf serum and 0.01% thimerosal. This assay was validated by determining linearity, recovery of added α1-PI, detection limit, and intra- and interassay precision. Control range for serum and fecal α1-PI concentration was determined for samples from 25 healthy pet dogs.

Results

The standard curve was linear between 5 and 50 ng/ml. Curves plotted after serial dilution of serum also were linear and ran parallel to the standard curve. Between- and within-assay coefficients of variation were 9.1 and 8.7%, respectively. The accuracy of the assay was tested by measuring the recovery of α1-PI added to serum and fecal extracts and ranged from 93 to 111%. The reference range of fecal α1-PI concentration was 0.023 to 5.67 (mean ± SD, 2.0 ± 1.82) μg/g and of seruma α1-PI was 0.901 to 1.96 (1.42 ± 0.32) g/L.

Conclusions

This ELISA had high precision, accuracy, and reproducibility for quantification of canine α1-PI concentration in serum and fecal extracts.

Clinical Relevance

Specific ELISA for α1-PI may be a useful test for the diagnosis of protein-losing enteropathy in dogs, and as such, will facilitate further characterization and better understanding of this canine disorder. (Am J Vet Res 1998;59:127–130)
Antipyrine pharmacokinetics and urinary excretion in female horses
Authors: Dyke T. M. , Sams R. A. , Hinchcliff K. W.
Published: January 2024

Objective

To measure renal clearance of antipyrine and urinary excretion of antipyrine (AP) metabolites in horses by use of validated high-performance liquid chromatography (HPLC) methods.

Animals

8 Standardbred mares.

Procedure

HPLC methods for measurement of AP in equine plasma and AP and its metabolites in equine urine were validated. Antipyrine (20 mg/kg of body weight) was administered IV, and blood samples and urine specimens were collected over 24 hours.

Results

Median plasma clearance of AP in horses was 6.2 ml/min/kg, of which < 2% could be attributed to renal clearance. Urinary excretion of AP and its metabolites over 24 hours accounted for < 22% of the AP dose administered. The major metabolite of AP in urine was 4-hydroxyantipyrine.

Conclusions and Clinical Relevance

Use of the proven validated methods for measuring AP and its metabolites indicated that AP has minimal renal clearance in horses, suggesting that plasma clearance of AP reflects hepatic clearance. Combined with AP metabolite data, the pharmacokinetics of AP may be useful for assessment of hepatic cytochrome P450 activity in horses. (Am J Vet Res 1998;59:280–285)
Long-term consequences of experimental desmotomy of the accessory ligament of the deep digital flexor tendon in adult horses
Authors: Becker C. K. , Savelberg H. H. C. M. , Buchner H. H. F. , Barneveld A.
Published: January 2024

Objective

To evaluate clinical and biomechanical consequences of desmotomy of the accessory ligament (AL) of the deep digital flexor tendon (DDFT) of equine forelimbs and determine whether this procedure is a viable treatment for chronic desmitis of the AL-DDFT.

Animals

6 adult Standardbred trotters.

Procedure

Biomechanical recordings obtained before and 6 months after desmotomy were compared. Walk and trot joint angles, ground reaction forces, peak joint moments, and tendon forces were assessed.

Results

Within 10 days after surgery, all horses were sound at a trot. Swelling, increased carpal flexion in the terminal stance phase, and incidental stumbling at the beginning of exercise were observed. Flexion angle in the carpal joints was significantly increased at the end of the stance phase. Peak moments around the distal interphalangeal joint and forces in the DDFT and AL-DDFT were decreased. Metacarpophalangeal joint angles, peak metacarpophalangeal joint moments, and peak loading of the suspensory ligament and the superficial digital flexor tendon were unchanged.

Conclusion

6 months after desmotomy, AL-DDFT strain was reduced without causing changes in joint angles or increasing tendon loads or joint moments that could be considered hazardous for the horses.

Clinical Relevance

Changes in locomotion that remained 6 months after AL-DDFT desmotomy would be acceptable for horses with chronic desmitis if conservative treatment failed. (Am J Vet Res 1998;59:347–351)
Production and characterization of canine osteosarcoma cell lines that induce transplantable tumors in nude mice
Authors: Nieves Mary Ann , Vahle John , Ackermann Mark , Howard Monica , Dietz Allan B. , Carpenter Susan L. , Cheville Norman
Published: January 2024

Objective

To produce and characterize cell lines from canine primary appendicular osteosarcomas that induce transplantable tumors in athymic nude mice.

Animals

57 six- to 8-week-old female athymic nude mice.

Procedure

Canine primary appendicular osteosarcoma tumors were harvested and cell lines were produced. Canine osteosarcoma (COSCA)-Toby (COSCA-T; 10 mice), COSCA-Princess (COSCA-Pr; 16) or canine osteosarcoma D-17 (ATCC CCL-183; 31) cells were injected into the proximal portion of the left tibia of nude mice to evaluate tumor production from each cell line; the right tibia served as the control. Tibial measurements were taken on alternating days to evaluate tumor growth during a 6-month period. Student's t-tests were used to determine whether size of the proximal portion of the left and right tibias differed significantly during the observation period.

Results

88% of mice receiving COSCA-Pr and 50% of mice receiving COSCA-T cells developed a tumor at the injection site by 9 days after implantation. The D-17 cells induced tumors in 50% of injected tibias; however, tumors were not detected for 79 days. Tumors generated from COSCA-Pr and COSCA-T cells in nude mice were histologically similar to the canine tumor from which they were developed.

Conclusion

New osteosarcoma cell lines that can reliably and rapidly induce transplantable tumors in nude mice were developed.

Clinical Relevance

Use of cell lines will allow evaluation of new treatments of canine primary appendicular osteosarcoma in a nude mouse model. (Am J Vet Res 1998;59:359–362)
Development and testing of a unique strain of Pasteurella haemolytica for use in studies on colonization of the respiratory tract of cattle
Authors: Briggs Robert E. , Frank Glynn H. , Zehr Emilie S.
Published: January 2024

Objective

To develop a unique strain of Pasteurella haemolytica, selectable from nasopharyngeal respiratory tract secretions, that retains the ability to efficiently colonize the respiratory tract of calves.

Animals

26 calves that each weighed approximately 200 kg.

Procedure

Rifampicin-resistant mutants of P haemolytica were developed and tested for in vitro growth rate and leukotoxin production. After instillation into the tonsils of calves, an isolate that was efficient at colonizing was selected and transformed, using electroporation, with a 4.2-kilobase (kb) plasmid encoding for streptomycin resistance. This isolate was instilled into the tonsils of 4 of 14 commingled calves to examine transmission of organisms. Nasal secretion and tonsil wash specimens were collected, cultured, and examined for P haemolytica. Serum antibody concentration was measured by means of indirect hemagglutination.

Results

Selected P haemolytica organisms colonized the tonsils and nasal passages for more than 2 weeks. Exposed calves and contact calves shed the organism, which was recovered from specimens of nasal secretions and tonsil washes. The 4.2-kb plasmid was lost during in vivo colonization.

Conclusions and Clinical Relevance

The selected rifampicin-resistant P haemolytica organism colonized tonsils and nasal passages in a manner similar to the wild-type organisms. Selective media suppressed other bacterial flora to the extent that a single colony-forming unit was detectable from 200 μl of specimen, a 100-fold improvement in detection sensitivity. The selectable strain spread rapidly among commingled calves. A 4.2-kb plasmid marker was unstable when P haemolytica replicated in vivo. (Am J Vet Res 1998;59:426–430)
Effect of dietary supplementation with fructo-oligosaccharides on fecal flora of healthy cats
Authors: Sparkes A. H. , Papasouliotis K. , Sunvold G. , Werrett G. , Gruffydd-Jones E. A. , Egan K. , Gruffydd-Jones T. J. , Reinhart G.
Published: January 2024

Objective

To investigate changes in the fecal flora of healthy cats after dietary supplementation with fructo-oligosaccharides (FOS).

Animals

12 healthy, barrier-maintained, specific-pathogen-free-derived adult cats.

Procedure

Fresh fecal samples for quantitative and qualitative bacteriologic examination were collected from each cat after ingestion of a replete dry (basal) diet for a minimum of 8 weeks. The diet was then supplemented with 0.75% FOS, and another fecal sample was collected after 12 weeks.

Results

Mean ± SD fecal aerobic, anaerobic, and total bacterial counts (log10 colony-forming units per gram of feces [CFU/g]) did not differ significantly between diets (8.3 ± 0.8, 9.2 ± 0.6, 9.4 ± 0.4, respectively, for the basal diet; and 8.4 ± 0.8, 9.7 ± 0.7, and 9.8 ± 0.7, respectively, for the FOS diet), although there was a trend for higher numbers of anaerobes and total bacteria associated with the FOS diet. Members of the genus Bacteroides, Clostridium perfringens, Escherichia coli, lactobacilli, and Plesiomonas shigeloides were the most prevalent bacteria isolated. Compared with samples from cats fed basal diet, there was a trend for increased mean counts of lactobacilli (P = 0.02) and Bacteroides spp (P = 0.05) after FOS supplementation, and a trend for decreased mean numbers of Escherichia coli (P = 0.03) and Clostridium perfringens (P = 0.08) to be associated with the FOS diet. Supplementation of FOS resulted in a median 164-fold increase in numbers of lactobacilli, 13.2-fold increase in Bacteroides spp, 98% reduction in numbers of C perfringens, and 75% reduction in numbers of E coli.

Conclusions

Supplementation of the diet with FOS resulted in alteration of the fecal flora of cats. (Am J Vet Res 1998;59:436–440)
Clinical and microbiological effects of controlled-release local delivery of minocycline on periodontitis in dogs
Authors: Hayashi Kazuhiko , Takada Kazuko , Hirasawa Masatomo
Published: January 2024

Objective

To evaluate the clinical and microbiological efficacy of minocycline in a subgingival local delivery system as an adjunct to tooth scaling and root planing in dogs with periodontal disease.

Animals

Nine 4- to 7-year-old Beagles with periodontitis.

Procedure

After scaling of teeth and root planing, 2 treatment and 1 or 2 control sites were selected for each dog: treated sites (n = 18) received minocycline hydrochloride periodontal formulation and control sites (n = 12) received ointment base (no minocycline). Gingival crevicular fluid was collected at a baseline (prior to treatment) and at week 4. Clinical and microbiological effects were evaluated and compared among sites.

Results

In minocycline-treated sites, clinical indices were significantly decreased at week 4, compared with those at baseline. Minocycline-treated sites were associated with a significant decrease in gingival crevicular fluid, probing depth, and bleeding on probing values, compared with those for control sites at week 4. Compared with that for control sites, total bacteria count in periodontal pockets of minocycline-treated sites had an obvious tendency to decrease by week 4. Proportions of Porphyromonas and Fusobacterium spp were significantly decreased at week 4, compared with proportions at control sites and with pretreatment (baseline) values.

Conclusions

When used as an adjunct to tooth scaling and root planing, minocycline periodontal formulation stimulated favorable clinical and antimicrobial responses. (Am J Vet Res 1998;59:464–467)
Cardiovascular effects of the α2-adrenergic receptor agonist medetomidine in clinically normal cats anesthetized with isoflurane
Authors: Golden A. L. , Bright J. M. , Daniel G. B. , Fefee D. , Schmidt D. , Harvey R. C.
Published: January 2024

Objective

To assess the cardiovascular effects of the α2-adrenergic receptor agonist medetomidine in healthy cats anesthetized with 2% isoflurane.

Animals

11 clinically normal cats.

Procedure

Cats were anesthetized with isoflurane, and catheters were inserted for measurement of aortic, left ventricular, and right atrial pressures. For data collection, end-tidal isoflurane concentration was reduced to 2%, and end-tidal CO2 was maintained at 35 to 40 mm of Hg by use of positive-pressure ventilation. After measurement of baseline data, medetomidine (0.01 mg/kg of body weight, IM) was administered and data were collected continuously for 75 minutes. At the end of data collection, incisions were closed and cats were allowed to recover from anesthesia.

Results

Medetomidine significantly increased mean arterial pressure and systemic vascular resistance. The increase in mean arterial pressure was maximal at 17.8 ± 7 minutes after medetomidine administration. Medetomidine also increased left ventricular peak systolic pressure, left ventricular end diastolic pressure, and right atrial pressure. Medetomidine significantly decreased heart rate and mean aortic flow.

Conclusions

The low dosage of medetomidine (0.01 mg/kg, IM) promoted severe vasoconstriction in isoflurane-anesthetized cats, and resulted in sustained increases in left ventricular preload and afterload. (Am J Vet Res 1998;59:509–513)
Diagnostic value of full-mouth radiography in dogs
Authors: Verstraete Frank J. Μ. , Kass Philip H. , Terpak Cheryl H.
Published: January 2024

Objective

To determine the diagnostic value of full-mouth radiography in dogs.

Sample Population

Prospective series of 226 dogs referred for dental treatment without previous full-mouth radiographic views being available.

Procedure

In a prospective nested case-control analysis of multiple outcomes in a hospital cohort of dogs presented for dental treatment, full-mouth radiographic views were obtained prior to oral examination and charting. After treatment, clinical and radiographic findings were compared, with reference to presenting problems, main clinical findings, additional information obtained from the radiographs, and unexpected radiographic findings. The importance of the radiographic findings in therapeutic decision-making was assessed.

Results

The main clinical findings were radiographically confirmed in all dogs. Selected presenting problems and main clinical findings yielded significantly increased odds ratios for a variety of other conditions, either expected or unexpected. Radiographs of teeth without clinical lesions yielded incidental or clinically important findings in 41.7 and 27.8% of dogs, respectively, and were considered of no clinical value in 30.5%. Radiographs of teeth with clinical lesions merely confirmed the findings in 24.3% of dogs, yielded additional or clinically essential information in 50.0 and 22.6%, respectively, and were considered of no value in 3.1%. Older dogs derived more benefit from full-mouth radiography than did younger dogs. Incidental findings were more common in larger dogs.

Clinical Relevance

Diagnostic yield of full-mouth radiography in new canine patients referred for dental treatment is high, and the routine use of such radiographs is justifiable. (Am J Vet Res 1998;59:686-691)
Anti-inflammatory benefits of tilmicosin in calves with Pasteurella haemolytica-infected lungs
Authors: Chin A. C. , Morck D. W. , Merrill J. K. , Ceri H. , Olson Μ. E. , Read R. R. , Dick P. , Buret A. G.
Published: January 2024

Objectives

To determine whether tilmicosin alters neutrophil infiltration or function, induces neutrophil apoptosis, and affects accumulation of leukotriene B4 (LTB4) or tumor necrosis factor-alpha (TNF-α) in lungs of calves experimentally infected with Pasteurella haemolytica.

Animals

12 weight-ranked Holstein calves.

Procedure

Calves were given 25% propylene glycol vehicle (n = 5) or tilmicosin (10 mg/kg of body weight; n = 6) subcutaneously, 18 hours and 15 minutes before intratracheal infection with 2 × 108 P haemolytica organisms. Two unmanipulated calves served as controls in some experiments. Rectal temperatures were recorded 15 minutes before, and at 3- hour intervals after infection for 24 hours. Samples obtained from bronchoalveolar lavage performed 3 and 24 hours after infection were used to assess colonization by P haemolytica, and neutrophil infiltration. Neutrophil phagocytosis of P haemolytica, membrane leakage as determined by trypan blue exclusion, oxidative function as determined by nitro blue tetrazolium reduction, and apoptosis, using electron microscopy and DNA fragmentation ELISA, were determined. Soluble TNF-α and LTB4 were measured from supernatants from bronchoalveolar lavage samples, using ELISA.

Results

Treatment with tilmicosin resulted in significant (P< 0.05) clearance of P haemolytica and neutrophil apoptosis at 3 hours, and decreased concentration of LTB4 at 24 hours. Rectal temperatures, neutrophil infiltration, phagocytosis, oxidative functions, membrane leakage, and soluble TNF-α concentrations were not significantly affected by tilmicosin.

Conclusion

Tilmicosin effectively controlled P haemolytica infection, induced neutrophil apoptosis, reduced pulmonary inflammation, and did not affect neutrophil infiltration or function.

Clinical Relevance

By inducing neutrophil apoptosis, tilmicosin prevents further amplification of inflammatory injury in P haemolytica-infected lungs. (Am J Vet Res 1998;59:765-771)
Serum-free culture of Pasteurella haemolytica optimized for leukotoxin production
Authors: Sun Yude , Clinkenbeard Kenneth D.
Published: January 2024

Objective

To screen supernatants of Pasteurella haemolytica cultures grown in 4 serum-free culture media for maximal leukotoxin (LKT) production and minimal protein concentration as an optimal source of LKT for purification.

Sample Population

One strain of P haemolytica biotype A serotype 1 originally isolated from the pneumonic lung of a calf.

Procedure

Pasteurella haemolytica was grown in brain-heart infusion (BHI) broth, yeast-tryptone broth, RPMI-1640 medium, and McCoy's modified 5A medium. Culture biomass and protein concentration, LKT activity, and LKT concentration in culture supernatants were measured. Effects of media pH and supplementation with metal cations and glucose on growth rate of P haemolytica and culture supernatant parameters were evaluated.

Results

Pasteurella haemolytica cultivated in BHI broth or RPMI-1640 medium containing 0.1M phosphate (pH 6.8) produced the highest concentrations of LKT. Supplementation of RPMI-1640 medium with 0.36 mM FeCl3 or 1.0 mM MgSO4 further increased specific activity of LKT in culture supernatant, but addition of 1 % glucose did not enhance LKT production. Leukotoxin production in MgSO4-supplemented RPMI-1640 medium was comparable to that in serum protein-supplemented medium.

Conclusions

Although BHI broth was superior to RPMI-1640 medium for P haemolytica growth and LKT production, the higher protein concentration and lower LKT specific activity made BHI broth a less desirable medium, compared with RPMI-1640 medium. Growth rate and LKT production with minimal protein content was optimal in pH 6.8 phosphate-buffered MgSO4-supplemented RPMI-1640 medium. This medium can serve as a source of culture supernatant for purification of LKT. (Am J Vet Res 1998;59:851–855)
Duration of effects of dietary fish oil supplementation on serum eicosapentaenoic acid and docosahexaenoic acid concentrations in dogs
Authors: Hansen Rodney A. , Ogilvie Gregory K. , Davenport Deborah J. , Gross Kathy L. , Walton Judy A. , Richardson Kristi L. , Mallinckrodt Craig H. , Hand Michael S. , Fettman Martin J.
Published: January 2024

Objective

To determine how long serum concentrations of ω-3 fatty acids remain elevated after cessation of dietary fish oil supplementation.

Animals

12 healthy Beagles.

Procedure

Baseline serum concentrations of linoleic acid, linolenic acid, arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) were measured. Dogs were then fed a diet supplemented with soybean oil or fish oil for 8 weeks, and serum fatty acid concentrations were measured while dogs were fed the experimental diets and for 18 weeks after they were switched to a maintenance diet.

Results

For dogs fed the fish oil diet, serum EPA and DHA concentrations were significantly increased by week 1 and remained increased for 7 (DHA concentration) or 3 (EPA concentration) weeks after dietary fish oil supplementation was discontinued.

Conclusions

In dogs, supplementation of the diet with fish oil may have effects for several weeks after dietary supplementation is discontinued.

Clinical Relevance

Studies of the effects of fish oil supplementation that use a crossover design should allow for an appropriate washout period. (Am J Vet Res 1998;59:864–868)
Use of peripheral temperature and core-peripheral temperature difference to predict cardiac output in dehydrated calves housed in a thermoneutral environment
Authors: Constable Peter D. , Walker Pamela G. , Morin Dawn E. , Foreman Jonathan H. , Thurmon John C.
Published: January 2024

Objective

To investigate the relation between cardiac output (CO) and peripheral (fetlock) temperature (PT) and core-peripheral (rectal-fetlock) temperature difference (CPTD) in dehydrated calves housed in a thermoneutral environment.

Animals

28 male dairy calves 3 to 10 days old.

Procedure

Severe dehydration and watery diarrhea were induced by administering diuretics (furosemide, hydrohlorothiazide, spironolactone) and sucrose solution. Cardiac output was measured by means of thermodilution, core temperature was determined by placing a digital thermometer in the rectum, and PT was measured by taping a thermistor to the left hind fetlock and insulating the thermistor from ambient air.

Results

In thermoneutral ambient temperatures (10 to 24 C), PT and CPTD were constant and independent of CO at normal or high CO values but were linearly dependent on CO below a critical value (78% of normal CO output). Regression equations were developed that predicted CO from measured PT or CPTD. At ambient temperatures below the lower critical temperature for neonatal calves (8 to 10 C), normal values for PT and CPTD in healthy calves were significantly different from those at thermoneutral ambient temperatures.

Conclusions and Clinical Relevance

Peripheral temperature and CPTD are practical, noninvasive, and inexpensive but only moderately useful methods for predicting CO in hemodynamically stable calves housed in a thermoneutral environment. Thus, these parameters are of some value in daily monitoring of the response to treatment and in determining need for IV fluid administration in dehydrated calves housed at a dry still-air temperature of 10 to 24 C but are of minimal to no value in calves housed at < 10 C. (Am J Vet Res 1998;59:874–880)