bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetic gait analysis assessment of meloxicam efficacy in a sodium urate-induced synovitis model in dogs
Authors: Cross Alan R. , Budsberg Steven C. , Keefe Thomas J.
Published: January 2024

Objective

To examine the ability of meloxicam, a cyclooxygenase inhibitor, to mediate the effects of sodium urate-induced acute stifle synovitis in dogs.

Animals

12 clinically normal adult hound-type dogs.

Procedure

A blinded, randomized, controlled single crossover design study was performed to determine the efficacy of meloxicam, using 2 dosage groups. In 2 experimental phases, dogs, according to group, received meloxicam (0.1 or 0.5 mg/kg of body weight) or matched volume of meloxicam vehicle, with a washout period of 21 to 28 days between phases. Blood samples for hematologic and biochemical analysis, as well as synovial fluid for cytologic analysis, were collected immediately before and approximately 24 hours after articular challenge of dogs under propofol anesthesia. Ground reaction forces (GRF) and subjective clinical scores were determined before and at 4, 8, 12, and 24 hours after articular challenge. Vertical force data included peak force, impulse, limb loading, and unloading rates. Craniocaudal data were divided into braking and propulsion phases and consisted of peak force and associated impulses.

Results

Except for propulsion impulse at 24 hours, all GRF variables were significantly greater at all postsynovitis induction times in the group receiving the high meloxicam dose. Significant differences in all GRF variables were seen at various times between the low-dose meloxicam group and the corresponding control group, and between the low- and high-dose meloxicam groups. Similar significance was seen in the subjective clinical evaluations. Strong correlations existed between the subjective and objective data.

Conclusions

Meloxicam was effective in attenuating the effects of sodium urate-induced acute synovitis in dogs. Kinetic gait data provided an objective measurement of lameness in an experimentally induced arthritis model and quantified lameness improvements in response to medication with a nonsteroidal anti-inflammatory drug. (Am J Vet Res 1997;58:626–631)
Hematologic and systemic toxicoses associated with carboplatin administration in cats
Authors: Hahn Kevin A. , McEntee Michael F. , Daniel Gregory B. , Legendre Alfred M. , Nolan Marie L.
Published: January 2024

Objective

To determine prevalence and severity of carboplatin-induced dose-limiting toxicoses in the cat.

Animals

9 healthy, 6- to 7-month-old cats weighing 4.7 (range, 3.0 to 6.5) kg.

Procedure

Cats were given a single IV bolus of carboplatin at a dosage of 150 (n = 3), 200 (n = 3), or 250 (n = 3) mg/m2 of body surface area.

Results

Dose-limiting neutropenia and thrombocytopenia were significant in all cats given carboplatin at 200 or 250 mg/m2. Weight loss, changes in appetite, and evidence of respiratory difficulty, as well as vomiting, diarrhea, or lethargy were not observed at any time during the 28-day period. At a highest dosage (250 mg/m2), the neutrophil nadir (560 ± 303 neutrophils/μl) was observed on day 17 and the platelet count nadir (96,500 ± 11,815 platelets/μl) was observed on day 14 after carboplatin administration.

Conclusions

Carboplatin appears to be safe and clinically well-tolerated when given IV as a single bolus at a dosage of 200 mg/m2 to clinically normal cats. The dose-limiting toxicity of a single IV administered bolus is neutropenia. The nadir of a 200 mg/m2 IV administered dose occurs on day 17 (1,110 ± 165 neutrophils/μl) and neutropenia (< 2,000 neutrophils/μl) lasts from day 14 through day 25 after carboplatin administration.

Clinical Relevance

The fatal dose-related pulmonary toxicosis observed in cisplatin-treated cats was inapparent in carboplatin-treated cats. To adequately determine the therapeutic role of carboplatin in tumor-bearing cats, a moderately tolerated dose of carboplatin of 200 mg/m2 given IV once every 4 weeks should be considered. (Am J Vet Res 1997;58:677– 679)
Repeated physical and cytologic characterizations of subcutaneous postvaccinal reactions in cats
Authors: Schultze A. E. , Frank L. A. , Hahn K. A.
Published: January 2024

Objectives

To examine local reactions and short-term cytologic responses of cats to administration of rabies virus (RV); FeLV; and combined feline rhinotracheitis, calicivirus, and panleukopenia virus (FRCPV) vaccines.

Animals

9 healthy 6- to 7-month-old specific-pathogen-free cats.

Procedure

One-milliliter doses of the aforementioned vaccines were administered SC (at different sites) to healthy, specific-pathogen-free cats. Each cat also received 1 ml of sterile saline solution SC as a control. Injection sites were visually examined and palpated daily for 4 weeks. Palpable lesions were measured by use of calipers. Temperature of the vaccination sites was measured weekly by use of a thermocouple. Aspirates were taken from vaccination sites weekly, and smears were submitted for cytologic analysis.

Results

There were no significant differences in lesion surface temperature among injection sites at any time. Injections of saline solution and FeLV vaccine resulted in no palpable lesions. The FRCPV vaccine elicited a minor reaction in 1 of the 9 cats. The RV vaccine caused palpable lesions in all cats. Smears of the aspirates from the sites of saline injection were poorly cellular. Cellularity of aspirates from the sites of FRCPV and FeLV vaccinations was moderate at week 1, and decreased with time. Inflammatory infiltrates were composed principally of lymphocytes, with fewer neutrophils and macrophages. In contrast, cellularity of aspirates from RV vaccination sites increased for 21 days and was characterized by increasing numbers of lymphocytes and macrophages.

Conclusions

RV vaccine used in this study induced palpable lesions in many cats. In contrast, FRCPV and FeLV vaccines elicited less severe lesions.

Clinical Relevance

Subcutaneous administration of killed virus vaccines in cats may result in palpable lesions that are detected by clients or clinicians. Aspiration cytologic examination may reveal a different characteristic pattern of cells that is dependent on the individual vaccine and time elapsed from vaccination. (Am J Vet Res 1997;58:719–724)
Growth of Pasteurella haemolytica and production of its leukotoxin in semi-defined media
Authors: Highlander Sarah K.
Published: January 2024

Objective

To develop semi-defined media that support growth of the bovine pathogen, Pasteurella haemolytica, and use them to examine production of leukotoxin and an arginine-binding protein by this organism.

Sample Population

10 P haemolytica A1 strains and 1 P multocida strain.

Procedure

Bacterial strains were cultivated at 37 C in media containing various amino acids, carbon sources, vitamins, and cofactors, and absorbance (OD600) was measured. Leukotoxin and arginine-binding protein production were assessed by immunoblot analysis.

Results

Optimal growth required supplementation with 0.1 % fetal bovine serum, gelatin, or purified bovine serum albumin. Calcium pantothenate and thiamine were essential for growth, and a variety of carbon sources could be utilized. In the complete medium, 15 amino acids were included; however, in the minimal medium, no amino acids were required. All strains (except P multocida) grew in the complete medium and 7 grew well in the minimal medium. Leukotoxin was not produced when amino acids were limiting, but could be enhanced by addition of 0.2% NH4SO4. Production of the arginine-binding protein was not affected by nitrogen availability or by presence of L-arginine.

Conclusions

Two media that support good growth of P haemolytica strains were developed. The minimal medium is simple to prepare and manipulate and its use revealed a potential role of nitrogen availability in the regulation of leukotoxin expression.

Clinical Relevance

Creation of these media will permit continued studies of the response of P haemolytica to environmental conditions that may mimic those encountered in the bovine respiratory tract during shipping. (Am J Vet Res 1997;58:749–754)
Secretion of apolipoprotein A-I by calf liver parenchymal cells
Authors: Miyamoto Toru , Katoh Norio
Published: January 2024

Objective

To determine: whether apolipoprotein A-I (apoA-I) is secreted by calf liver parenchymal cells; the isoprotein pattern and association with lipids of secreted apoA-I; and effects of steroid hormones on apoA-I secretion.

Sample Population

6 male Holstein calves (1 to 2 weeks old) as a cell culture source.

Procedure

apoA-I in culture medium was detected by immunoblot analysis, and its concentration was measured by use of an ELISA. The isoprotein pattern was analyzed by use of two-dimensional polyacrylamide gel electrophoresis. Associations of apoA-I with cholesterol and phospholipids were examined by ultracentrifugal analysis of the culture medium.

Results

Concentration of apoA-I in culture medium increased linearly up to 24 hours. The protein synthesis inhibitors, actinomycin D and cycloheximide, suppressed apoA-I accumulation in the medium in dose-dependent manner. Molecular mass of this protein in culture medium was 28 kd, and was indistinguishable from apoA-I of plasma. Four isoproteins with different isoelectric points (1 = 5.75; 2 = 5.67; 3 = 5.58; and 4 = 5.46) were detected. Of these, isoprotein 2 was the major species. By comparison, isoprotein 4 was the predominant species in plasma, and isoprotein 5 (isoelectric point = 5.38) was newly detected instead of isoprotein 1. Approximately 33% of apoA-I in culture medium was found in lipid-rich fractions, whereas the rest was found in nonlipoprotein fractions. Dexamethasone (10−8 to 10−6M) significantly (P < 0.001) increased apoA-I concentration in the medium, and the stimulatory effect was significantly (P < 0.001) suppressed by the simultaneous addition of 10−5M progesterone. Progesterone itself (10−6 to 10−5M) had little effect on apoA-I secretion; estradiol (10−14 to 10−6M) also had no significant effect.

Conclusions

apoA-I is synthesized by calf liver parenchymal cells, and the secreted protein is modified during circulation. Moreover, apoA-I synthesis and secretion by the cells appear not to be largely influenced by hormones, except for dexamethasone. (Am J Vet Res 1997;58:811–815)
Airborne transmission of Actinobacillus pleuropneumoniae and porcine reproductive and respiratory syndrome virus in nursery pigs
Authors: Torremorell Montserrat , Pijoan Carlos , Janni Kevin , Walker Roger , Joo Han Soo
Published: January 2024

Objective

To document airborne transmission of Actinobacillus pleuropneumoniae and porcine reproductive and respiratory syndrome virus (PRRSV) infection in nursery pigs.

Animals

32 two-week-old pigs obtained from 3 farms, but with similar Landrace × Yorkshire genetics for trial 1 of each experiment; 16 pigs for trial 2 of the A pleuropneumoniae experiment; and 14 pigs for trial 2 of the PRRSV experiment.

Procedure

In experiment 1, pigs were inoculated with A pleuropneumoniae serotype 1 (6/8) or were left as contacts (2/8). At the beginning of trial 1, pigs were seronegative to A pleuropneumoniae serotypes 1 and 5 on the basis of results of an ELISA, but had positive results on the A pleuropneumoniae hemolysin I (Apx1)-neutralization test. Pigs in trial 2 had negative results on both tests. Pigs of trial 1 of experiment 2 were inoculated with a PRRSV virulent field isolate (MN-1b); pigs of trial 2 were inoculated with the virus reference strain VR-2332. Aerosol-exposed pigs were placed on the other side of the air duct and kept there for 2 to 7 weeks depending on evidence of airborne transmission.

Results

In trial 1 of experiment 1, evidence of airborne transmission was not found. In trial 2, most airborne-exposed pigs died as a result of A pleuropneumoniae infection 12 days after initiation of the experiment. In trial 1 of experiment 2, all inoculated pigs (8/8) seroconverted, but only 2 of 8 contact-exposed pigs seroconverted. Aerosol-exposed pigs did not seroconvert nor was virus isolated. In trial 2, all inoculated and contact-exposed pigs seroconverted. All aerosol-exposed pigs seroconverted after 21 days, and virus was isolated at 16 days.

Conclusions

A pleuropneumoniae was transmitted by air at a distance of 1 m when pigs were fully susceptible to the organism. Transmission of PRRSV appeared to be strain dependent; when reference strain VR-2332 was used, airborne transmission of PRRSV was documented. (Am J Vet Res 1997;58:828–832)
Age-related changes in the pharmacokinetic disposition of diazepam in foals
Authors: Norman W. M. , Court M. H. , Greenblatt D. J.
Published: January 2024

Objective

To evaluate changes in the pharmacokinetic disposition of diazepam in foals from 4 to 84 days of age.

Sample Population

4 male and 2 female full-term mixed-breed foals.

Procedure

Diazepam terminal half-life, volume of distribution, clearance, free fraction, unbound volume of distribution, free clearance, peak desmethyldiazepam concentration, and area under the desmethyldiazepam concentration-time curve were determined after IV administration of 0.25 mg of diazepam/kg of body weight to foals at 4, 21, 42, and 84 days of age.

Results

Disposition of diazepam was best described using a two-compartment model. Clearance and free fraction values (mean ± SEM) determined at 4 days (5.06 ± 0.79 and 51 ± 8 ml/kg/min, respectively) were significantly less than those obtained at 21 (8.64 ± 0.95 and 87 ± 11 ml/kg/min), 42 (7.31 ± 0.82 and 83 ± 10 ml/kg/min), and 84 (8.41 ± 0.56 and 100 ± 12 ml/kg/min) days. Volume of distribution and unbound volume of distribution values determined at 4 days (1.57 ± 0.11 and 16.0 ± 1.7 L/kg, respectively) were significantly less than those found at 21 (2.66 ± 0.33 and 26.8 ± 3.9 L/kg), 42 (3.00 ± 0.42 and 33.9 ± 5.0 L/kg), and 84 (2.55 ± 0.35 and 30.2 ± 5.3 L/kg) days. Peak plasma desmethyldiazepam concentration obtained at 4 days (22.7 ± 2.4 ng/ml) was significantly lower than that obtained at 21 (36.1 ± 4.5 ng/ml), 42 (38.3 ± 4.8 ng/ml), and 84 (34.6 ± 2.1 ng/ml) days.

Conclusions

Factors likely to affect the pharmacokinetic disposition of diazepam in foals, such as body composition and hepatic enzyme activity, are in transition during the first 21 days of life. These have opposing effects on diazepam clearance and volume of distribution so that terminal half-life remains unchanged. However, clearance determines whether diazepam will accumulate with repeated doses, and care should be taken when administering repeated doses to foals < 21 days old. (Am J Vet Res 1997;58:878–880)
Effects of flunixin meglumine on short circuit current in equine colonic mucosa in vitro
Authors: Freeman David E. , Inoue Olivia J. , Eurell Thomas E.
Published: January 2024

Objectives

To study the effect of flunixin meglumine on short circuit current (Isc) in equine right ventral colon in vitro.

Samples

Intestinal mucosa from healthy horses and ponies.

Procedure

Isc was measured in mucosa from the right ventral colon mounted in Ussing chambers. In experiment 1, collection and incubation solutions were: control (no additions): flunixin meglumine, 4 μg/ml; indomethacin, 10-6M; and flunixin meglumine (4 μg/ml) with 10-6M prostaglandin E2. In experiment 2, incubation conditions were: control (plain Krebs-Ringer bicarbonate [KRB] solution); flunixin meglumine, 4 μg/ml in KRB; chloride-free buffer solution; flunixin meglumine (4 μg/ml) in a chloride-free buffer solution; and plain KRB with 10-6M prostaglandin E2. In experiment 3, tissue from 3 groups (n = 6 each) of animals: controls, physiologic saline solution given IV at 10 minutes before euthanasia; flunixin meglumine (1.1 mg/kg of body weight, IV) given at 10 minutes before euthanasia; and treatment similar to controls, except that tissues were incubated with 8 μg of flunixin meglumine/ml of bathing medium.

Results

Flunixin meglumine and indomethacin reduced Isc to approximately a third of control current (P < 0.05), but coincubation with flunixin meglumine and 10-6M prostaglandin E2 restored Isc close to the control value. Incubation with 10-6M prostaglandin E2 alone did not change Isc. When chloride was substituted with isethionate, flunixin meglumine had no effect on Isc. Flunixin meglumine given before euthanasia or included at a concentration of 8 μg/ml in all tissue preparation and incubation solutions reduced Isc (P < 0.05).

Conclusions

Flunixin meglumine given IV or added to bathing solutions decreased Isc in equine right ventral colon by a mechanism that appeared to involve prostaglandin-mediated chloride secretion.

Clinical Relevance

Our results suggest that flunixin meglumine given IV to horses at recommended doses could alter putative effects of colonic prostaglandins. (Am J Vet Res 1997;58:915–919)
Identification of thrombospondin as a high molecular mass protein released from activated equine platelets
Authors: Lipscomb Desireé L. , Boudreaux Mary K. , Paxton Ralph , Spano Joseph , Welles Elizabeth G. , Schumacher John
Published: January 2024

Objective

To establish the existence of platelet-derived proteins in equine plasma, with the future goal of developing an assay for the detection of in vivo platelet activation.

Animals

5 mature healthy horses.

Procedure

Platelet-rich plasma and platelet-poor plasma were prepared from anticoagulated blood. Platelets were separated from plasma proteins by gel filtration, then activated with 0.5 μM platelet-activating factor. Protease inhibitors were added, and the released platelet proteins were harvested. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed on the released platelet proteins and platelet-poor plasma, and the resultant silver-stained bands were compared. Immunoblot analysis was performed on released platelet proteins, using an antibody to human thrombospondin; human platelet-derived proteins served as the positive control for the antibody.

Results

Released platelet proteins in the presence of β-mercaptoethanol (reduced samples) contained several proteins that were not observed in plasma including (mean ± SEM) 194 ± 2, 159 ± 2, 151 ±2, 104 ± 2, and 95 ± 1 kd. Immunoblots of released platelet proteins had a prominent 180 ± 2-kd protein in reduced samples that was recognized by an antibody to human thrombospondin, and with prolonged color development, 2 additional less prominent proteins (166 ± 1 and 155 ± 1 kd) were observed.

Conclusions

Several proteins are released from activated equine platelets that are not detectable in normal equine plasma. Thrombospondin is one of the high molecular mass proteins released by activated equine platelets.

Clinical Relevance

An assay can be developed for detection of thrombospondin in equine plasma and may be useful for detection of in vivo platelet activation in horses. (Am J Vet Res 1997;58:954–960)
Comparison of whole-cell antigens of pressure- and formalin-killed Flexibacter columnaris from channel catfish (Ictalurus punctatus)
Authors: Bader J. A. , Klesius P. H. , Vinitnantharat S.
Published: January 2024

Objective

To identify and compare immunodominant antigens in whole-cell lysates of pressure-and formalin-killed Flexibacter columnaris.

Animals

Sera from naturally infected and vaccinated channel catfish.

Procedures

Whole-cell lysates of pressure- and formalin-killed F columnaris were compared, and antigens were isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The antigens were identified by staining, western blotting, and specific monoclonal antibodies to glycoproteins. Western blotting was performed, using sera from channel catfish (Ictalurus punctatus) with naturally acquired F columnaris infection and sera from channel catfish vaccinated with an experimental prototype F columnaris vaccine.

Results

Whole-cell lysates of pressure and formalin-killed F columnaris shared 4 proteins: 100, 80, 66, and 60 kd. The 60-kd antigen was a glycoprotein. Western blotting, using sera from naturally infected channel catfish, revealed the same proteins for pressure- and formalin-killed F columnaris. Sera from vaccinated fish reacted only to pressure-killed lysate antigens.

Conclusions

Pressure- and formalin-killed F columnaris whole-cell lysates share 100-, 80-, 66-, and 60-kd proteins and are recognized by antibodies from naturally infected catfish and those vaccinated with formalin-killed F columnaris. Formalin treatment modifies or inactivates the 60-kd protein antigens, rendering them unrecognizable to antibodies from channel catfish naturally infected with F columnaris, suggesting that formalin-killed F columnaris may not be suitable for use as a bacterin against columnaris disease. (Am J Vet Res 1997;58:985–988)
Measurement of cyclic variation in ultrasonic integrated backscatter in conscious, unsedated, clinically normal dogs
Authors: Fuentes Virginia Luis , Moran Carmel M. , Schober Karsten , McEwan Joanna Dukes , Brown Helen , Sutherland George R. , McDicken W. Norman
Published: January 2024

Objective

To assess the feasibility and repeatability of measuring ultrasonic integrated backscatter in unsedated conscious dogs, using a protocol previously validated in pigs with open thorax.

Animals

11 clinically normal conscious unsedated German Shorthair Pointers.

Procedure

A modified commercially available echocardiography system was used to record long-axis views of the heart. The radiofrequency data from 15 consecutive frames were digitized and analyzed. Regions of interest were chosen within the myocardium, and the ultrasonic integrated backscatter within each region was calculated in the time domain for each frame.

Results

Cyclic variation in integrated backscatter values was observed, with maximal values at end-diastole and minimal values at end-systole. Mean ± SD amplitude of cyclic variation was 5.81 ± 3.86 dB over all the regions chosen.

Conclusions

Results agreed with those obtained by other investigators working with dogs with open thorax and those with closed thorax while under general anesthesia. The analysis of the components of variance indicates that this is a consistent, reliable technique in conscious unsedated dogs.

Clinical Relevance

Integrated ultrasonic backscatter measurement provides a noninvasive means of tissue characterization. Use of this protocol reliably yields cyclic variation in integrated backscatter and could be applied clinically to dogs with myocardial disease. (Am J Vet Res 1997;58:1055–1059)
Within- and between-examiner repeatability of distraction indices of the hip joints in dogs
Authors: Smith Gail K. , LaFond Elizabeth , Gregor Thomas P. , Lawler Dennis F. , Nie Robert C.
Published: January 2024

Objective

To evaluate in vivo repeatability of the distraction index method of evaluating hip joint laxity in dogs.

Animals

31 two-year-old Labrador Retrievers.

Procedure

Each dog was anesthetized and radiographically evaluated for hip joint laxity 4 times: twice by an experienced examiner and twice by an examiner who had no previous knowledge of or training in the technique prior to the first day of testing. Distraction indices (DI) were determined from the radiographs and intraclass correlation coefficients were calculated to evaluate the repeatability of DI measurements between and within examiners.

Results

Intraclass correlation coefficients were high (range, 0.85 to 0.94). Lower limits of the 95% confidence intervals for the intraclass correlation coefficients ranged from 0.75 to 0.89.

Conclusions

Between- and within-examiner repeatabilities of DI measurements were high, suggesting that the technique is clinically reliable.

Clinical Relevance

Distraction index is a reliable measure of hip joint laxity and a good predictor of the risk of development of degenerative joint disease associated with hip dysplasia in dogs. Establishment of high repeatability of DI measurements suggests that the stress-radiographic method may be used by multiple examiners with the expectation of comparable and consistent results. (Am J Vet Res 1997;58:1076–1077)
Induction of gross and microscopic lesions of porcine proliferative enteritis by Lawsonia intracellaris
Authors: Joens L. A. , Nibbelink S. , Glock R. D.
Published: January 2024

Objective

To evaluate experimental induction of porcine proliferative enteritis (PPE), using cell cultured Lawsonia intracellularis (ileal symbiont intracellularis), and to determine whether dexamethasone administration or age of the host or both affects susceptibility to L intracellularis infection.

Animals

Thirty-two 3- or 7-week-old pigs.

Procedures

Lawsonia intracellularis was extracted from tissue with lesions of PPE and was subcultured in a continuous Henle 407 cell line at 37 C under an atmosphere of 5% CO2. Three- or 7-week-old pigs were inoculated orally with 100 ml of a 10-day-old cell culture preparation of the bacterium or infective intestinal homogenates. Control pigs were inoculated with uninfected Henle cells. Pigs were observed daily for clinical signs of infection and necropsied at death or at termination of the study. Lesions in the small and large intestines were recorded.

Results

Diarrhea was observed in pigs 4 to 7 days after inoculation with the pure culture agent or homogenates and lasted throughout the study period. Histologic lesions consistent with PPE were detected in pigs inoculated with pure culture. Intestinal lesions were absent in control pigs inoculated with uninfected Henle cells. Differences in lesions were not significant between treatment groups that varied in age or were receiving dexamethasone. Tissue specimens from pigs at necropsy were culture negative for Salmonella spp and Serpulina hyodysenteriae.

Conclusion and Clinical Relevance

Gross and microscopic lesions typical of acute PPE were induced in pigs by use of a cell culture agent. Age differences and the stress induced by administration of dexa-methasone had no effect on development of intestinal lesions. (Am J Vet Res 1997;58:1125–1131)
Scintigraphic biodistribution and plasma kinetics of indium 111-labeled transferrin in dogs
Authors: Berry Clifford R. , Fisher Paul , Koblik Philip D. , Guilford W. Grant , Hornof William H.
Published: January 2024

Objective

To determine plasma clearance kinetics and imaging biodistribution of indium 111-labeled transferrin (111In-TF) in dogs.

Animals

7 adult dogs.

Procedure

After 30 minutes’ incubation of 18.5 MBq (0.5 mCi) of 111InCl3 with 1 ml of serum (n = 3) or 1 ml of plasma (n = 4) at 37 C, dogs were given autologous 111In-TF IV, and serial blood samples and right lateral and dorsal scintigraphic images were obtained immediately and 1, 3, 5, 9, 22, and 48 hours later. Blood and plasma clearance kinetics were determined from a least-squares, nonlinear fit of the sample radioactivity data. Blood radioactivity was compared with plasma radioactivity to determine the extent of cellular labeling. Imaging biodistribution was characterized by subjective and objective assessment of blood pool, liver, gastrointestinal (abdomen) tract, kidney, and bone marrow activity.

Results

111In-TF plasma clearance was best described by a biexponential fit, with early and late clearance half-times of 6 and 49 hours, respectively. The 111In was not redistributed between transferrin (plasma proteins) and blood cells. Imaging studies documented progressive liver and bone marrow uptake of the 111In-TF over 48 hours. Some radioactivity was evident in the colon of 1 dog on 48-hour images. Decay-corrected count rates (counts/pixel/mCi/kg/min) within the abdominal region of interest increased over the 48-hour imaging period and exceeded the blood pool (cardiac) activity at 20 hours after injection.

Conclusion

111In-TF has a biexponential plasma clearance in clinically normal dogs, with early and late clearance half-time of 6 and 49 hours, respectively. Scintigraphically, 111In-TF localizes to sites of iron storage (bone marrow and liver) over time. Some loss of 111In-TF via the gastrointestinal tract may be seen on late 48-hour images.

Clinical Relevance

111In-TF appears to be a viable radiopharmaceutical for use in dogs, with specific application for identifying those with protein-losing enteropathy. (Am J Vet Res 1997;58:1188–1192)
Prevalence, vasculature, and innervation of myocardial bridges in dogs
Authors: Tangkawattana P. , Muto M. , Nakayama T. , Karkoura A. , Yamano S. , Yamaguchi M.
Published: January 2024

Objective

To report gross anatomic examination of the canine myocardial bridge (MB), a muscular band found above the coronary artery (CA), with respect to its occurrence, location, vascularization, and innervation.

Sample Population

629 canine hearts obtained within 1 to 3 hours after euthanasia.

Procedure

After an incision was made at the left fifth intercostal space, the pericardial sac was cut open, and if an MB was present, the heart, lungs, and annexed structures were removed together and subsequently subjected to macroscopic examination of MB musculature and innervation after formalin fixation. Vascular casting was performed by use of methyl methacrylate perfusion.

Results

Of the 629 canine hearts examined, 189 (30%) had MB, occurrence of which was independent of sex, age, and breed. Among 13 MB-containing specimens examined in detail, there was great variation in thickness (0.11 to 2.24 mm; mean, 0.45 mm) of MB and distance (24 to 236 μm; mean, 103 μm) between the MB and the paraconal interventricular branch of the left CA (PIBL). One pair or 2 pairs of blood vessels from the PIBL supplied the MB muscle. Venous blood returned to the coronary circulation via the branches of the great coronary vein coursing on both sides of the PIBL, in close contact with the PIBL and the groove wall. The 2 veins rejoined at the upper portion of the PIBL and passed obliquely to the coronary groove under the left auricle, and finally drained the blood through the coronary sinus into the right ventricle. Innervation to the MB muscle was derived from nerve branches of the middle cervical ganglion and left vagus nerve.

Conclusion

Prevalence and localization of MB in dogs and human beings are similar. Vascularization of the MB muscle originates from the PIBL. The cervical ganglion and vagus nerve control the MB muscle. (Am J Vet Res 1997;58:1209–1215)
Cardiovascular effects of equipotent isoflurane and alfentanil/isoflurane minimum alveolar concentration multiple in cats
Authors: Pascoe Peter J. , Ilkiw Jan E. , Fisher Linda D.
Published: January 2024

Objective

To determine whether administration of opioids to anesthetized cats induced less cardiovascular depression than that induced by an equivalent amount of anesthetic alone, and to measure endocrine responses to a noxious stimulus.

Animals

6 healthy female cats.

Procedure

Anesthesia was induced with isoflurane and was maintained for 60 minutes at 1.3 isoflurane MAC. Blood gas tensions, pH, and plasma alfentanil and hormone concentrations, blood pressures, and cardiac output were measured. A noxious stimulus was applied for 5 minutes, while blood acquisition and measurements were repeated. Alfentanil was administered IV to achieve estimated plasma concentration of 500 ng/ml, and end-tidal isoflurane concentration was reduced by 35%. After another 60 minutes, blood was obtained and measurements were taken, then a second 5-minute noxious stimulus was applied while blood acquisition and measurements were retaken.

Results

Alfentanil administration and reduction of isoflurane concentration significantly increased body temperature, heart rate, mean arterial pressure, mean pulmonary arterial pressure, stroke index, cardiac index, hemoglobin, oxygen delivery index, Pvo2 and Pvco2, dopamine, epinephrine (EPI), norepinephrine (NOREPI), and cortisol values, and significantly decreased arterial and venous pH. Application of a noxious stimulus significantly increased heart rate, stroke index, cardiac index, Pao2, oxygen delivery index, arterial and venous pH, and NOREPI values, and decreased bicarbonate, Paco2, Pvco2, and EPI values. Alfentanil administration blunted cardiac index, Paco2, oxygen delivery index, arterial pH, Pao2, and EPI, and NOREPI responses to a noxious stimulus.

Conclusions

Compared with isoflurane alone, alfentanil administration and reduction of isoflurane MAC improved cardiovascular variables, and blunted respiratory, hormonal, and most hemodynamic responses to a noxious stimulus in cats.

Clinical Relevance

Use of the balanced opioid anesthesia regimen induced some beneficial effects in healthy cats; effects were similar to, although greater in nature, than effects induced by a noxious stimulus. (Am J Vet Res 1997;58:1267–1273)
Noninvasive monitoring of fetal heart rate during the last ten days of gestation in sows
Authors: Cohen S. , Mulder E. J. H. , van Oord H. A. , Jonker F. H. , van der Weijden G. C. , Taverne M. A. M.
Published: January 2024

Objective

To develop and evaluate a noninvasive technique for monitoring and analyzing porcine fetal heart rate (FHR) during late gestation.

Animals

8 fetuses of 8 pluriparous sows in late gestation.

Procedure

With the sow positioned in lateral recumbency, the most caudal fetus was identified, using real time ultrasonography, and its heart rate was recorded for 60 minutes by use of Doppler cardiography. The same fetus was identified and monitored repeatedly during the last 10 days of gestation, excluding the 24 hours before delivery. Visual inspection and computerized analysis of the recordings were performed.

Results

66 one-hour recordings were obtained from 8 fetuses, 1 in each of 8 sows. Mean signal loss was 37.5%. Episodes of low FHR and low FHR variation (FHR pattern A) alternated with episodes of high FHR and high FHR variation (FHR pattern B). This cyclic alternation between 2 distinct FHR patterns was observed in 46 of 66 (69.7%) recordings, and suggests the presence of different behavioral states in fetal pigs. Basal FHR decreased toward parturition in 7 fetuses, but increased in 1 fetus with abdominal ascites. Basal FHR and long-term FHR variation were negatively correlated (r[S) = −0.73; P < 0.001).

Conclusion

Noninvasive monitoring of FHR is possible and feasible during late gestation in pigs. This method permits longitudinal studies under pathophysiologic conditions and the evaluation of the effects of endogenous and exogenous influences on porcine FHR. (Am J Vet Res 1997;58:1285–1290)
Effect of pentoxifylline, flunixin meglumine, and their combination on a model of endotoxemia in horses
Authors: Baskett Anne , Barton Michelle Henry , Norton Natalie , Anders Brendan , Moore James N.
Published: January 2024

Objective

To compare effects of a single dose of pentoxifylline (PTX), flunixin meglumine (FM), and their combination (FM/PTX) in a model of equine endotoxemia.

Animals

24 healthy horses, aged 2 to 15 years.

Procedure

4 groups (n = 6/group) received 30 ng of Escherichia coli O55:B5 endotoxin/kg of body weight, IV, over 30 minutes, and 1 of the following preparations 15 minutes before and 8 hours after endotoxin infusion: FM, 1.1 mg/kg; PTX, 8 mg/kg; FM/PTX, 1.1 mg of FM and 8 mg of PTX/kg; and saline solution bolus (ENDO). Clinical and hematologic variables were measured over 24 hours.

Results

Compared with ENDO, FM given before endotoxin significantly reduced TxB2, and 6-keto-PGF1 concentrations, pulse, rectal temperature, and attitude score. Pentoxifylline given before endotoxin resulted in significantly higher 6-keto-PGF1 concentration at 1.5 hours and significantly lower PAI-1 activity at 12 hours. Tumor necrosis factor and IL-6 activities in horses given PTX alone were not significantly different from values in those given the saline bolus. FM/PTX induced effects similar to those of FM alone on endotoxin-induced changes in temperature and TxB2 concentration, and 6-keto-PGF1 concentration was significantly lower than that in horses of the ENDO group at 1 hour. In horses of the FM group, 6-keto-PGF1 concentration was significantly lower than that in horses of the ENDO group, from 0.5 hour to 2 hours. Horses of the FM and FM/PTX groups had significantly higher IL-6 activity at 1.5 and 2 hours than did horses of the PTX and ENDO groups; those of the FM and FM/PTX groups had significantly lower WBC count than did those of the PTX and ENDO groups.

Conclusions

FM/PTX may help offset deleterious hemodynamic effects of endotoxin more effectively than does either FM or PTX alone. (Am J Vet Res 1997;58:1291–1299)
Effects of pentoxifylline infusion on response of horses to in vivo challenge exposure with endotoxin
Authors: Barton Michelle Henry , Moore James N. , Norton Natalie
Published: January 2024

Objective

To evaluate the effect of pentoxifylline on response of horses to in vivo challenge exposure with endotoxin.

Animals

24 healthy horses in 3 treatment groups: pentoxifylline, endotoxin, or endotoxin and pentoxifylline.

Procedure

Horses of the pentoxifylline group were given a bolus of pentoxifylline (7.5 mg/kg of body weight, IV), followed by an infusion (3 mg/kg/h) over 3 hours, and those of the endotoxin group were given 20 ng of endotoxin/kg IV over 30 minutes. Those of the combination group were given both of the aforementioned compounds; pentoxifylline was administered immediately after endotoxin. Clinical (rectal temperature, heart and respiratory rates, blood pressure) and hematologic (WBC count; whole blood recalcification time; plasma fibrinogen, thromboxane B2, and 6-keto-prostaglandin F1α, concentrations; plasma plasminogen activator inhibitor activity; and serum tumor necrosis factor and interleukin 6 activities) variables were evaluated over 24 hours.

Results

Compared with baseline values, there were no significant changes in any variable over time in the horses receiving only pentoxifylline, with the exception of a significant increase in WBC count. Rectal temperature, heart rate, mean blood pressure, WBC count, whole blood recalcification time, fibrinogen concentration, plasminogen activator inhibitor activity, tumor necrosis factor and interleukin 6 activities, and plasma thromboxane B2 concentration changed significantly over time in horses of the endotoxin and endotoxin-pentoxifylline combination groups. Respiratory rate and plasma 6-keto-prostaglandin F1α concentration changed significantly over time only in horses of the endotoxin group. Compared with values for the endotoxin group, rectal temperature and respiratory rate were significantly lower, and whole blood recalcification time was longer for the endotoxin/pentoxifylline group.

Conclusion

Beneficial effects of pentoxifylline are limited when it is administered IV to horses after in vivo challenge exposure with endotoxin. (Am J Vet Res 1997;58:1300–1307)
In vitro flow characteristics of the Ahmed and self-constructed anterior chamber shunts
Authors: Strubbe D. Todd , Gelatt Kirk N. , MacKay Edward O.
Published: January 2024

Objective

To compare in vitro opening pressures (OP) and closing pressures (CP) of the Ahmed VS-1 and VS-2 glaucoma valves with those of several selfconstructed valve ‘prototypes,’ and to assess their ability to maintain perfusion pressures between 6 and 21 mm of Hg.

Sample Population

Ahmed VS-1 (n = 6), 2 groups of Ahmed VS-2 (group 1: n = 12; group 2: n = 14), and self-constructed valves with linear incisions in the long axis of the tube wall (n = 6) or X-shaped incisions in the tube walls (n = 2).

Procedure

Valves were perfused with deionized water, lactated Ringer's solution (LRS), Dulbecco's modified Eagle's medium (DMEM), DMEM plus 50% equine serum (ES), and 100% ES. Flow rates of 2.85, 4.2, 6.0, 9.0, and 12.0 μl/min were used for each perfusate. Valves were tested 3 times for reproducibility, and OP/CP were compared for each system.

Results

OP/CP of the VS-1, VS-2 (group 1), VS-2 (group 2), and linear 1.0-cm incisional valves with thick tubing consistently increased with increasing perfusion rate. Linear 0.5-cm (thick tubing) and 1.0-cm (thin tubing) incisional valves had increasing OP/CP with increasing perfusion rate in all but a few instances. Mean OP/CP decreased with increasing perfusate osmolarity for all perfusates except LRS, using the VS-1 and V-2 (group 2) valves. Mean OP/CP were consistently lower for VS-1 than VS-2 (group 1) valves at any given flow rate and for any given perfusate. Mean OP/CP were consistently lower for VS-2 (group 1) than VS-2 (group 2) valves at any given flow rate and for any given perfusate. The linear 0.5-cm incisional valves with thick and thin tubing induced the highest mean OP/CP, maximizing at > 30 mm of Hg.

Conclusions

Only the VS-2 (group 2) valves consistently had mean OP/CP between 6 and 21 mm of Hg for all perfusates and at all flow rates.

Clinical Relevance

Anterior chamber shunts, although imperfect, appear to offer a physiologically sound alternative for glaucoma management. (Am J Vet Res 1997;58:1332–1337)
Accuracy of localizing radiopaque markers by abdominal radiography and correlation between their gastric emptying rate and that of a canned food in dogs
Authors: Guilford W. Grant , Lawoko Charles R. O. , Allan Frazer J.
Published: January 2024

Objectives

To determine accuracy of abdominal radiography in locating radiopaque markers in the gastrointestinal tract and to assess correlation between gastric emptying rate of radiopaque markers and that of canned food.

Animals

17 healthy dogs.

Procedure

Dogs were fed thirty 1.5-mm markers and ten 5-mm markers mixed in sufficient food to meet 25% of their daily caloric intake. They were then euthanatized by administration of an overdose of barbiturate at 1, 2, 5, 8, or 12 hours after eating and the abdomen was radiographed. The stomach, small intestine, and large intestine were then separated and radiographed in isolation. The wet and dry weights of the stomach contents were determined. The apparent and actual locations of the markers and the gastric emptying rates of markers, wet matter, and dry matter were compared, using rank correlation.

Results

All comparisons indicated significant (P < 0.025), high correlation coefficients (> 0.92). The mean difference between the apparent and actual locations of the markers was < 3% for all comparisons. The mean difference between the percentage of small markers and large markers retained in the stomach and that of dry matter was 7.8 (SD, 6.2; range, 0 to 18)% and 11.9 (SD, 12.5; range, 0 to 44)%, respectively.

Conclusions

The gastric emptying and orocolic transit rates of the markers were accurately predicted by abdominal radiography. The gastric emptying rate of the diet and the small markers and, to a lesser extent, the large markers was closely correlated.

Clinical Relevance

When fed with a special canned food diet, radiopaque markers can be used to assess the gastric emptying rate of food with sufficient accuracy for clinical purposes. (Am J Vet Res 1997;58:1359–1363)
Rehabilitation of dogs with surgically treated cranial cruciate ligament-deficient stifles by use of electrical stimulation of muscles
Authors: Johnson J. M. , Johnson A. L. , Pijanowski G. J. , Kneller S. K. , Schaeffer D. J. , Eurell J. A. , Smith C. W. , Swan K. S.
Published: January 2024

Objective

To determine effect of electrical muscle stimulation (EMS) on rate and degree of return to function of the limb and development of degenerative joint disease (DJD) after surgical creation and subsequent stabilization of the cranial cruciate ligament (CrCL)-deficient stifle.

Animals

12 clinically normal adult large (19.5 to 31.5 kg) dogs.

Procedure

Dogs were anesthetized, and the right CrCL was severed via arthrotomy, destabilizing the stifle. After 3 weeks, the stifle was surgically stabilized. Three weeks later, 6 dogs were subjected to an EMS treatment protocol for the thigh muscles. At 5, 9, 13, and 19 weeks after stifle destabilization, treated (n = 6) and control (n = 6) dogs were evaluated for return of stifle function. Gross and histologic evaluations of the stifles were performed at 19 weeks after stifle destabilization.

Results

Treated dogs had significantly (P = 0.001) better lameness score than did control dogs. There was less palpable crepitation of the stifle in treated dogs (P = 0.06); treated dogs also had significantly (P = 0.01) fewer radiographic signs of bone changes. Thigh circumference was significantly (P = 0.02) larger in treated dogs.There was less gross cartilage damage (P = 0.07) in the EMS-treated dogs, but more medial meniscal damage (P = 0.058, cranial pole; P = 0.051, caudal pole).

Conclusions

Improved lameness scores, larger thigh circumference, and decreased radiographically apparent bony changes observed for the treated group of dogs support the hypothesis that dogs treated by EMS after surgical stabilization of the CrCL-deficient stifle had improved limb function, with less DJD, than did dogs treated with the currently accepted clinical protocol of cage rest and slow return to normal activity. However, results of force plate evaluation did not support the hypothesis. Increased meniscal damage in dogs treated by EMS may be cause for concern. (Am J Vet Res 1997;58:1473–1478)
Antimicrobial susceptibility of Fusobacterium necrophorum isolated from bovine hepatic abscesses
Authors: Lechtenberg K. F. , Nagaraja T. G. , Chengappa M. M.
Published: January 2024

Objective

To determine the resistance and susceptibility to antimicrobial compounds of Fusobacterium necrophorum isolates from bovine hepatic abscesses.

Procedure

37 isolates of F necrophorum (21 subsp necrophorum and 16 subsp funduliforme) isolated from bovine hepatic abscesses were obtained from cultures grown and maintained in anaerobic brain heart infusion broth. A broth dilution method was used as an initial screening to determine general susceptibility to 31 antimicrobial compounds. The minimal inhibitory concentrations (MIC) of 19 of the antimicrobial compounds that inhibited growth in the initial test were determined by use of the broth microdilution method.

Results

Fusobacterium necrophorum isolates were generally susceptible to penicillins, tetracyclines (chlortetracycline and oxytetracycline), lincosamides (clindamycin and lincomycin), and macrolides (tylosin and erythromycin), and were resistant to aminoglycosides (kanamycin, neomycin, gentamicin, and streptomycin), ionophores (except narasin), and peptides (avoparcin, polymyxin, and thiopeptin). The 5 antimicrobials (bacitracin, chlortetracycline, oxytetracycline, tylosin, and virginiamycin) that have FDA approval for prevention of liver abscesses in feedlot cattle were inhibitory to F necrophorum. Differences in antimicrobial susceptibility patterns were observed between the 2 subspecies only for clindamycin and lincomycin. The MIC of F necrophorum isolates from antibiotic-fed cattle were similar to those for isolates from nonantibiotic-fed cattle.

Conclusions

The MIC of FDA-approved antibiotics were not reflective of the efficacy of antibiotics in preventing liver abscesses in feedlot cattle. Also, continuous feeding of tylosin did not appear to select resistant F necrophorum. (Am J Vet Res 1998;59:44–47)