bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyaluronate and large molecular weight proteoglycans in synovial fluid from horses with various arthritides
Authors: Tulamo Riitta-Mari , Houttu Jukka , Tupamäki Antero , Salonen Matti
Published: January 2024

Objective

To investigate the presence of large molecular weight (MW) proteoglycans (PG) and hyaluronate (HA) in synovial fluid (SF) from horses with various arthritides and from control joints.

Design

Horses with acute (< 2 weeks) or chronic (> 4 weeks) lameness were examined by clinical examination, intrasynovial anesthesia, radiography, arthroscopy, and SF analysis. Joints were grouped on the basis of diagnosis: acute traumatic arthritis, chronic traumatic arthritis (with a subgroup of degenerative joint disease), intra-articular fracture, and infectious arthritis.

Animals

31 horses with arthritis and 9 control horses; altogether 43 SF samples were analyzed.

Procedure

High-performance liquid chromatography was used to assess HA and large MW PG in SF samples.

Results.

A PG peak was identified in 8 of 23 SF samples of joints with chronic traumatic arthritis, 4 of which had no or minimal abnormal radiographic findings but mild articular cartilage fibrillation detected by arthroscopy, and in 3 joints with intra-articular fracture and 1 with resolving infectious arthritis, but not in joints with acute traumatic arthritis or in control joints. There was significant difference (P < 0.01) in mean (± SEM) HA concentration between control joints and joints with chronic traumatic arthritis (0.32 ± 0.04 g/L; n = 9 vs 0.18 ± 0.01 g/L; n = 23).

Conclusions

Large MW PG fragments are released into equine SF in the course of articular disease and can be detected simultaneously with HA by high-performance liquid chromatography.

Clinical Relevance

The SF HA concentration can be used as diagnostic marker for chronic traumatic arthritis. However, SF PG or other marker cannot be used for diagnosing or monitoring degenerative joint disease. (Am J Vet Res 1996;57:932–937)
In vitro evaluation of four methods of attaching transfixation pins into a fiberglass cast for use in horses
Authors: McClure Scott R. , Watkins Jeffrey P. , Hogan Harry A.
Published: January 2024

Objective

To compare the axial stability provided by 4 methods of attaching transfixation pins into a fiberglass cast.

Design

Axial stability of 4 methods of transfixation pin attachment to a fiberglass cast cylinder was determined in vitro. Methods of attachment included simple incorporation of the pins into the cast, placement of a washer and nut on the pin and incorporation into the cast, extension of pins beyond the cast and attachment to a steel halo, and washers within the cast and attachment to a steel halo.

Population

A model was designed to simulate a transfixation cast applied to the equine metacarpus. 8 identical constructs were present in each of the 4 groups. 6 fiberglass cylinders were also tested to identify the contribution of the cast cylinder to the overall stability of the transfixation cast.

Procedure

Load-displacement curves were recorded, and a stiffness modulus was calculated for each treatment group and for a simple fiberglass cylinder without transfixation pins.

Result and Conclusion

There was no significant difference among the 4 methods of attachment. The fiberglass cast material appears to be the major determinant of axial stability. (Am J Vet Res 1996;57:1098–1101)
Serum thyroxine and triiodothyronine responses of hyperthyroid cats to thyrotropin
Authors: Mooney Carmel T. , Thoday K. L. , Doxey D. L.
Published: January 2024

Objective

To document circulating total thyroxine (T4) and triiodothyronine (T3) responses after administration of thyrotropin (thyroid-stimulating hormone [TSH]) to hyperthyroid and healthy cats and assess the value of these responses as an additional diagnostic test for hyperthyroidism.

Design

Prospective case series.

Animals

21 healthy and 40 hyperthyroid cats.

Procedure

Serum total T4 and T3 concentrations were measured by radioimmunoassay before and 6 hours after administration of 0.5 IU of bovine TSH/kg of body weight.

Results

In healthy cats, serum total T4 concentration increased after administration of TSH (mean ± SD, 114.0 ± 36.4 nmol/L) representing a mean increment 3 times baseline concentration (mean ± SD, 33.7 ± 7.6 nmol/L). In hyperthyroid cats, the relative increase in serum total T4 concentration was significantly (P < 0.001) different; baseline values (mean ± SD, 236.2 ± 146.0 nmol/L) increased minimally after TSH administration (mean ± SD, 308.1 ± 178.9 nmol/L). There was a significant negative correlation (rs = −0.366) between relative increase in serum total T4 concentration after TSH administration and baseline concentration in hyperthyroid cats. In 3 cats with equivocal baseline serum total T4 concentration the T4 response to TSH administration was indistinguishable from that in healthy cats. Serum total T3 response to TSH administration was significantly (P < 0.001) lower in hyperthyroid, compared with healthy, cats but the T3 response in healthy cats was more variable than that for T4.

Conclusions

Thyrotoxic cats with high baseline serum total T4 concentration have a limited T4 response to TSH stimulation. Hyperthyroid cats with equivocal baseline serum total T4 concentrations have T4 responses after TSH stimulation similar to those of healthy cats. Measurement of serum total T3 concentration provides no additional information.

Clinical Relevance

The TSH response test is of limited value in diagnosing hyperthyroidism in cats. (Am J Vet Res 1996;57:987–991)
Simultaneous diuresis cysto-urethrometry and multichannel urethral pressure profilometry in continent female dogs
Authors: Nickel Rafael F. , van den Brom Walter E.
Published: January 2024

Objective

To study a combined urodynamic technique for assessment of urethral closure and bladder storage function in female dogs.

Animals

20 healthy, adult, sexually intact female dogs of various breeds.

Procedure

Urethral pressure profilometry and continuous urethral pressure registration during high-diuresis cystometry (cysto-urethrometry) were studied in dogs sedated with xylazine. Pressures were measured, using a flexible polyvinylchloride multichannel catheter connected to a perfusion system. Urine production and volume were determined by radionucleotide dilution analysis of urine samples. Urethral pressure profilometry was performed first, followed by cystourethrometry. Maximal urethral pressure and maximal urethral closure pressure of consecutive profiles and their mean values were determined. Closure pressure at its highest and lowest level and at micturition threshold and absolute and relative magnitude of urethral pressure variation were determined in the high-pressure zone of the urethra while the bladder filled, enforced by diuresis. Bladder pressure and volume at the micturition threshold and static compliance also were determined.

Results

Differences in mean and variance between variables listed were not significant. Urethral closure pressure varied from 5 to 67 cm of H2O during bladder storage. So-called unstable detrusor contractions were observed in 6 dogs.

Conclusions

Several variables for the assessment of the dynamics of urethral closure and bladder storage function obtained by the technique reported here are reproducible. Values from this study are considered reference values for further studies.

Clinical Relevance

The reported technique can be helpful in the investigation of complicated urinary incontinence in female dogs. (Am J Vet Res 1996;57:1131-1136)
Polymerase chain reaction evidence of Ehrlichia chaffeensis, an etiologic agent of human ehrlichiosis, in dogs from southeast Virginia
Authors: Dawson Jacqueline E. , Biggie Kristine L. , Warner Cynthia K. , Cookson Kalen , Jenkins Suzanne , Levine Jay F. , Olson James G.
Published: January 2024

Objective

To ascertain whether dogs are naturally infected with Ehrlichia chaffeensis.

Animals

74 dogs from 5 animal shelters and 1 kennel in 3 cities and 3 counties in southeastern Virginia were tested during June 1991.

Procedure

Blood was drawn from 74 dogs; 73 were tested serologically for antibodies reactive to E chaffeensis and E canis, and 38 were tested for the presence of E chaffeensis, E canis, and E ewingii by polymerase chain reaction (PCR). Serologic testing by indirect fluorescent antibody assay. Nested PCR used Ehrlichia-wide outside primers to detect initial products, followed by use of species-specific primers for identification.

Results

28 (38.4%) dogs had a positive test result (minimum titer, ≥ 1:64) for antibodies reactive to E chaffeensis, and 28 (38.4%) had a positive reaction to E canis. PCR analysis indicated that 8 (42.1 %) dogs were positive for E chaffeensis and 6 dogs (31.6%) were positive for E ewingii. All dogs had negative results of the PCR test for E canis.

Conclusion

Dogs are potential reservoirs of E chaffeensis.

Clinical Relevance

Canine E chaffeensis infection may be more prevalent than E canis or E ewingii infection in this region of the United States. (Am J Vet Res 1996;57:1175-1179)
Identification of lactoferrin in bovine tears
Authors: Brown Michael H. , Brightman Alan H. , Fenwick Bradley W. , Rider Maureen A.
Published: January 2024

Objective

To determine whether bovine tear film contains the iron-binding glycoprotein, lactoferrin.

Animals

40 Adult Hereford, Angus, and Simmental cattle.

Procedure

Protein analysis: pooled bovine tears were used for protein analysis (size exclusion high-performance liquid chromatography [HPLC] fractionation). HPLC was used for tear analysis. A diode array detector was used (215 and 280 μm) for chromatogram analysis and comparisons.

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE): protein electrophoresis was performed, using 7.5% running gels with 4% stacking gels. Molecular weight of proteins in the unknown samples was determined as recommended by the manufacturer of the standards.

Protein sequencing: amino acid sequencing, using automated Edman degradation of HPLC purified protein, was performed. The sequence obtained was compared with the known protein sequence of bovine lactoferrin.

Results

HPLC analysis of whole bovine tears resulted in a consistent chromatogram. Peak collection was performed to recover a protein from the bovine tear film with chromatogram characteristics nearly identical to purified bovine lactoferrin. Silver-stained SDS-PAGE of this peak revealed a band with molecular mass consistent with bovine lactoferrin (estimated mass of 78 kd). The first 13 amino acid residues of this protein were identical to the amino acid sequence of bovine lactoferrin.

Conclusion

Analysis of whole bovine tears, using size exclusion HPLC, SDS-PAGE, and amino acid sequencing, provided evidence that bovine tears contain lactoferrin.

Clinical Relevance

Lactoferrin probably exerts a bacteriostatic effect in bovine tear film. Locally produced lactoferrin may bathe the ocular surface and sequester iron from potential pathogens. (Am J Vet Res 1996;57:1369-1372)
Characteristics of fetal heart rate changes during the expulsive stage of bovine parturition in relation to fetal outcome
Authors: Jonker F. H. , Geijn H. P. Van , Chan W. W. , Rausch W.-D. , Van der Weijden G. C. , Taverne M. A. M.
Published: January 2024

Objective

To characterize fetal heart rate (FHR) patterns of nonacidotic (N-AC) and acidotic (AC) calves during the expulsive stage of parturition.

Animals

32 calves born to heifers, either unassisted or by moderate traction.

Procedure

Cardiotocograms (CTG) evaluated qualitatively (visual) and quantitatively by a moving window technique (width 10, shift 5 minutes) for baseline FHR, variability, and periodic alterations (accelerations and decelerations).

Results

Significant differences were apparent between increase in baseline FHR of N-AC and AC calves; change in FHR (Δ-FHR), taking into account individual FHR, is a more discriminating parameter. The predominant reaction to uterine contraction is a decrease in FHR; variable decelerations were the most common type in both groups, and late decelerations were seen only in AC calves. Additional characteristics of variable decelerations were more frequently seen in AC calves.

Conclusions

CTG parameters during expulsion can discriminate between AC and N-AC calves, but specific characteristics are not exclusively restricted to AC or N-AC calves.

Clinical Relevance

CTG recordings during bovine parturition in cattle provide information on the fetal condition and can be used in the future to study the effects of medication and manipulations to the fetus. (Am J Vet Res 1996;57:1373-1381)
Evaluation of ploidy of mature canine megakaryocytes, using Feulgen staining and microspectrophotometry
Authors: Boudreaux Mary K. , Ebbe Shirley
Published: January 2024

Objective

To evaluate megakaryocyte size and ploidy, using Feulgen staining and microspectrophotometry, in adult dogs with normal platelet count.

Animals

Group A contained 8 and group B contained 11 adult dogs.

Procedure

Megakaryocytes were evaluated by light microscopy and staged according to maturation status. Stage-III megakaryocytes were measured and mapped for future relocation. Bone marrow aspirates were destained and restained, using the Feulgen method. Previously identified stage-III megakaryocytes were measured for DNA content, using microspectrophotometry.

Results

Megakaryocyte size correlated with ploidy values, and mean sizes within ploidy groups were significantly (P < 0.05) different from each other for both groups. The modal ploidy value of stage-III megakaryocytes, which represented 18% of the total megakaryocyte population of the combined groups, was 32N. This is in contrast to results of flow cytometric studies, which indicated that the modal ploidy value for all canine megakaryocytes was 16N.

Conclusions

Reasons for the disparate results between microspectrophotometric techniques and flow cytometry include maturation stage of the megakaryocyte population evaluated and percentage of megakaryocytes within that maturation stage. Flow cytometric methods, which evaluate all megakaryocytes detectable by antibody, may include cells still capable of DNA synthesis, resulting in a shift in the observed modal ploidy value.

Recognition of the difference between canine and human megakaryocyte ploidy distribution is important, particularly in studies in which the dog is used as an animal model for human megakaryocytopoiesis. (Am J Vet Res 1996;57:1434–1437)
Field evaluation of doramectin for treatment of gastrointestinal nematode infections and louse infestations of cattle
Authors: Phillips F. E. , Logan N. B. , Jones R. M.
Published: January 2024

Objective

To evaluate the safety and efficacy of doramectin given by injection at a dosage of 200 μg/kg of body weight for treatment of gastrointestinal nematodiasis or louse infestations of cattle.

Animals

1,031 mixed-breed cattle were treated in the nematode study and 418 were treated in the louse study.

Procedure

Naturally parasitized cattle were given 200μg of doramectin/kg or an equivalent volume of saline solution, SC. In nematode experiments, fecal samples were collected from each animal 1 week before treatment, at time of treatment, and at weekly intervals thereafter for 3 weeks. In louse experiments, louse counts were carried out for each animal on the day of treatment and 14 and 28 days later. All cattle were weighed at the time of treatment and at the end of the experiment.

Results

By 21 days after doramectin treatment, fecal egg counts had decreased to zero in 9 of 10 experiments and to 1 egg/g in the remaining experiment. Differences between treatment groups were significant (P < 0.0001) in all instances. Pretreatment coproculture identified Haemonchus, Ostertagia, Cooperia, Trichostrongvlus, and Nematodirus as the represented genera. Doramectin was 100% effective in eliminating infestation with Linognathus vituli, Haematopinus eurysternus, and Solenopotes capillatus. Infestation with the chewing louse Damalinia bovis was reduced overall by 86%. For all species, post-treatment louse counts were significantly (P < 0.02) less for doramectin-treated cattle than for controls. Adverse reactions to doramectin were not apparent in either study.

Conclusion and Clinical Relevance

Injectable doramectin at a dosage of 200 μg/kg is safe and effective for treatment of gastrointestinal nematodiasis and louse infestations of cattle under field conditions. (Am J Vet Res 1996;57:1468-1471)
Immunolocalization of stromelysin, tumor necrosis factor (TNF) α, and TNF receptors in atrophied canine articular cartilage treated with hyaluronic acid and transforming growth factor β
Authors: Comer Joan S. , Kincaid Steven A. , Baird Aubrey N. , Kammermann John R. , Hanson Reid R. , Ogawa Yasushi
Published: January 2024

Objective

To evaluate the ability of hyaluronic acid (HA), with and without transforming growth factor β (TGF-β), to stabilize the catabolic processes associated with atrophy of articular cartilage.

Animals

20 adult, skeletally normal, hound-type dogs.

Procedure

Dogs (20 to 30 kg) were randomly assigned to 1 of 5 groups. One group served as untreated controls. Bivalve casts were placed on the left hind limbs of the remaining 16 dogs to limit weightbearing and motion of the limb for 92 days. One group served as the cast control. Beginning on day 56, 3 groups received aseptic intra-articular injections in the left stifles of either 5 mg of HA or 5 mg of HA containing either 20 or 50 μg of TGF-β. Intra-articular injections were repeated at 4-day intervals until the end of the study. On day 92, stifles were harvested at necropsy. Medial femoral condyles were histologically processed, and the articular cartilage was stained for the presence of proteoglycans, stromelysin, tumor necrosis factor (TNF) α, and TNF receptors (p55 and p75).

Results

Decreased metachromasia was evident in the cartilage matrix of all cast groups, with the smallest decrease in the HA-treated group. Stromelysin was immunolocalized in articular cartilage of the cast (left) limbs of cast control and both HA/TGF-β-treated groups. TNF-α was localized in articular cartilage of all cast (left) and right limbs, except those of the HA-treated group. Receptors for TNF were observed in both limbs of untreated control and cast control groups and cast limbs of HA/TGF-β-treated groups. The receptors were not localized in the right limbs of the HA with or without TGF-β-treated groups. TGF-β did not decrease stromelysin or TNF-α or receptors at the doses used.

Conclusions

HA may mediate a chondrostabilizing influence on articular cartilage by down-regulating TNF-α. Importantly, HA appeared to exert its inhibitory influence on TNF-α, as well as stromelysin and TNF receptors, on a systemic basis.

Clinical Relevance

Results provide insight into the mode of action of HA as a therapeutic agent for arthritis and its stabilizing influence on cartilage metabolism. (Am J Vet Res 1996;57:1488-1496)
Apical root canal anatomy of canine teeth in cats
Authors: Hennet Philippe R. , Harvey Colin E.
Published: January 2024

Objective

To determine the apical anatomy of canine teeth in cats.

Sample Population

70 permanent canine teeth of cats.

Procedure

The teeth were extracted, cleaned, and radiographed, and the root canals were stained with India ink, then cleared in methyl salicylate. The apical root canal anatomy was studied by examining dental radiographs and microscopic measurements performed on the cleared specimens.

Results

Apical root canal anatomy in cats has the same "sprinkler-rose" appearance as seen in dogs. The mean length of the radiodense apex on radiographs was 2.8 ± 1.2 mm. The mean lengths of the apical ramifications were 1.9 ± 0.4 and 1.6 ± 0.4 mm for upper and lower canine teeth, respectively; mean numbers of apical ramifications were 13 ± 6 and 12 + 5, respectively; and mean ratios (length of ramifications/length of root) were 0.16 ± 0.03 and 0.15 ± 0.04, respectively. There was significant (P < 0.05) difference in the length of apical ramifications between upper and lower canine teeth and significant (P < 0.05) positive correlation between the length of the root and the length of apical ramifications for all canine teeth.

Conclusion

Primary apical foramen is not present in mature canine teeth of cats.

Clinical Relevance

There is little risk of apical penetration by files during endodontic therapy of canine teeth of cats; however, the multiple foramina require that apical instrumentation is thorough to prevent soft tissue remnants causing failure of the procedure. (Am J Vet Res 1996;57:1545–1548)
Modulation of matrix metalloprotease 13 (collagenase 3) gene expression in equine chondrocytes by interleukin 1 and corticosteroids
Authors: Caron John P. , Tardif Ginette , Martel-Pelletier Johanne , DiBattista John A. , Geng Changshan , Pelletier Jean-Pierre
Published: January 2024

Objective

To determine whether matrix metalloprotease 13 (MMP-13; collagenase 3) is produced by equine chondrocytes and to investigate modulation of its expression by recombinant human interleukin β (rhIL-1β) and corticosteroids.

Procedure

Equine chondrocytes in monolayer culture were stimulated with rhIL-1β. Total RNA was extracted, purified, and reverse transcribed into DNA. Using appropriate primers, a putative MMP-13 fragment was amplified by polymerase chain reaction, and cloned into a bacterial vector. The resultant fragment was purified and sequenced, then was used to prepare a digoxigenin-labeled cRNA probe. Monolayer cultures of first-passage chondrocytes were treated with rhIL-1β in the presence or absence of dexamethasone (10-6M) or methylprednisolone acetate (10-9M to 10-5M), in addition to positive and negative controls. Cellular RNA was extracted and resolved on agarose gels and subjected to northern blot analysis, using the equine MMP-13 probe.

Results

Reverse transcriptase-polymerase chain reaction enabled isolation of a 0.6-kb fragment of equine MMP-13 cDNA that had 93% homology with the human MMP-13 cDNA sequence. rhIL-1 significantly stimulated MMP-13 expression in the chondrocytes. Methylprednisolone acetate inhibited the stimulatory effects of rhIL-1 in dose-dependent manner that was statistically significant at 10-5M.

Conclusions

Novel information was gained on the existence of MMP-13 and its expression in equine chondrocytes, which suggests a possible role for this enzyme in matrix degradation in horses with arthritis. (Am J Vet Res 1996;57:1631–1634)
Cardiac electrophysiologic measurements in dogs before and after intravenous administration of atropine and propranolol
Authors: Wright Kathy N. , Hines Debrah A. , Bright Janice M.
Published: January 2024

Objectives

To assess baseline cardiac electrophysiologic (EP) measurements in dogs undergoing a clinically used anesthetic protocol, and to study the effects of IV administered atropine and propranolol on these EP variables.

Animals

15 adult dogs with cardiac function within reference ranges, as assessed by physical examination, electrocardiography, and echocardiography.

Procedure

13 cardiac EP variables were measured in isofluorane-anesthetized dogs before and after IV administration of atropine and propranolol. Multipolar electrode catheters were positioned against the endocardium of the dorsal portion of the right atrium, His bundle region, and right ventricular apex. Incremental pacing and pacing-extrastimulus techniques were used to obtain EP measurements of the sinoatrial node, atrioventricular node, and atrial and ventricular myocardia in the control state and after IV administration of 0.04 mg of atropine and 0.2 mg of propranolol/kg of body weight.

Results

Only the atrial effective refractory period changed significantly after muscarinic and β-adrenergic receptor antagonism. Marked individual variation in response to these agents, however, was apparent. Two dogs had substantial decreases in sinoatrial and/or atrioventricular nodal measurements, and 7 dogs had notable increases in atrioventricular nodal measurements.

Conclusions

Cardiac EP measurements vary widely among clinically normal, isofluorane-anesthetized dogs. Individual dogs can have variable degrees of autonomic tone, which can be minimized by pharmacologic receptor antagonism.

Clinical Relevance

Although effects of receptor antagonism at clinically applicable dosages were not significant for 12 of 13 measurements, withdrawal of vagal tone can induce marked EP changes and may be important during a clinical study. (Am J Vet Res 1996;57:1695–1701)
Investigation of an outbreak of Aleutian disease on a commercial mink ranch
Authors: Jackson M. Keven , Winslow Scott G. , Dockery Larry D. , Jones Jedd K. , Sisson Donald V.
Published: January 2024

Objective

To determine the modes of transmission of Aleutian mink disease in a natural outbreak.

Animals

5,580 black and 9,087 brown mink from a ranch with an outbreak of Aleutian mink disease.

Procedure

Each mink had serum tested by counter-electrophoresis for Aleutian disease antibody. If a mink was seropositive for Aleutian disease virus by counter-electrophoresis, it was considered to be infected. Correlation of prevalence of the disease in kits and parents was determined. Spatial arrangement of infected and uninfected mink also was studied.

Results

Infected black dams were more likely to produce infected kits than were uninfected dams. In contrast, infected black sires were less likely to produce infected kits than were uninfected sires. In brown mink, in which prevalence of Aleutian disease was lower, transmission from infected dams and sires to kits was apparent. Infected black mink appeared to be more efficient in transmitting the disease horizontally than were infected brown mink. Although the spatial arrangement of infected mink indicated that mechanical transmission of the disease may be the most efficient mode of horizontal transmission, airborne transmission also occurred.

Conclusions and Clinical Relevance

Infected sires with nonprogressive Aleutian disease may confer protection to their kits in the face of a severe outbreak. Brown mink may be less able to transmit the virus horizontally than are black mink. Airborne transmission is substantial, but may not be as efficient as mechanical transmission. (Am J Vet Res 1996;57:1706–1710)
Cardiopulmonary and gastrointestinal motility effects of xylazine/ketamine-induced anesthesia in horses previously treated with glycopyrrolate
Authors: Singh Sukhpal , McDonell Wayne N. , Young Simon S. , Dyson Doris H.
Published: January 2024

Objective

To assess the usefulness of glycopyrrolate (GLY) in preventing the decrease in cardiac index (Cl) usually caused by xylazine (XYL)/ketamine (KET)-induced anesthesia in horses.

Animals

6 healthy horses.

Procedure

Horses were treated with saline solution or 2.5 μg of GLY/kg of body weight, administered IV. 15 minutes later, XYL (1 mg/kg) was administered IV followed 5 minutes later by KET (2 mg/kg) administration. The horses were positioned in left lateral recumbency, insufflated with 15 L of oxygen/min, and maintained for 30 minutes on the infusion of 0.05 mg of XYL and 0.1 mg of KET/kg/min. Mean, systolic, and diastolic arterial blood pressures, mean pulmonary arterial and central venous pressures, heart rate, Cl, and arterial and mixed venous blood gas tensions were recorded up to 40 minutes after anesthesia induction. Intestinal motility was assessed by auscultation of 4 abdominal quadrants for 24 hours after induction. Data were analyzed by Wilcoxon's rank-sum test for nonparametric observations, and by ANOVA for repeated measures and Scheffe's test for continuous parametric variables.

Results

Horses given GLY had significantly higher heart rate; mean, systolic, and diastolic arterial blood pressures; Cl; oxygen delivery; and mixed venous oxygen tensions, with significantly less tissue oxygen extraction, compared with saline-treated horses. Both groups had complete loss of intestinal motility associated with general anesthesia.

Conclusions

GLY significantly reduced the cardiovascular dysfunction attributable to general anesthesia with XYL and KET. The return of intestinal motility was delayed by 3 to 6 hours without causing any serious side effects. (Am J Vet Res 1996;57:1762–1770)
Resynthesis of glycogen in skeletal muscle from Standardbred trotters after repeated bouts of exercise
Authors: Hyyppä Seppo , Räsänen Leena A. , Pösö A. Reeta
Published: January 2024

Objective

To determine glycogen resynthesis rate and changes in plasma metabolite concentrations in horses before and after repeated exercise.

Animals

6 clinically normal Standardbred trotters.

Procedure

Horses trotted distances of 3,000, 3,000, and 2,000 m (trial A) and 3 days later, trotted 2, 100, 2, 100, and 1,600 m (trial B). Horses had 1 hour rest periods between bouts of exercise. Trotting speed was increased with each exercise bout, up to a near maximal. Muscle biopsy specimens and venous blood samples were obtained before each trial and 0, 4, 24, 48, and 72 hours after the third bout. Blood samples were also taken between exercise bouts. Muscle glycogen content and plasma glucose, glycerol, nonesterified fatty acid, and triglyceride concentrations were determined.

Results

Muscle glycogen content was significantly decreased immediately after exercise from 473 ± 45 to 329 ± 79 mmol/kg of dry weight in trial A, and from 472 ± 128 to 347 ± 59 mmol/kg in trial B. Further decreases were measured 4 hours after exercise. Glycogen resynthesis was negligible 24 hours after exercise. Basal muscle concentrations of glycogen were obtained 72 hours after exercise in trial A (472 ± 128 mmol/kg), but not in trial B (279 ± 52 mmol/kg). Plasma concentrations of glucose were greater than or equal to before-exercise values. Plasma concentrations of lipid metabolites, glycerol, triglycerides, and nonesterified fatty acids, were less than before-exercise values 2 to 72 hours after exercising.

Conclusions

Repeated bouts of exercise decrease glycogen repletion rate, which is not attributable to hypoglycemia, but may be influenced by limited availability of lipids for energy production. (Am J Vet Res 1997;58:162–166)
Skeletal muscle characteristics and metabolic response to exercise in young Standardbreds
Authors: Ronéus N. , Essén-Guslavsson B.
Published: January 2024

Objective

To determine whether performance capacity in a group of young trained Standardbreds is related to skeletal muscle characteristics and metabolic response to exercise.

Animals

13 clinically normal 2-year-old Standardbreds.

Procedure

Venous blood and middle gluteal muscle biopsy samples were obtained from each horse within 1 to 2 minutes after trotting at high speed for 1,600 m.

Results

There was a positive correlation between plasma lactate and muscle glucose-6-phosphate (G-6-P) concentrations and trotting speed. There was a negative correlation between muscle adenosine triphosphate concentration and trotting speed, plasma lactate concentration, and muscle lactate and G-6-P concentrations. Muscle concentration of G-6-P was positively correlated with muscle lactate and plasma lactate concentrations. Percentage of type-1, -2A, and -2B fibers in skeletal muscle and muscle enzyme activities of hexokinase, 3-OH-acyl-CoA dehydrogenase, lactate dehydrogenase, and citrate synthase were not correlated with trotting speed.

Conclusion

Speed of trotting at a distance of 1,600 m in young trained Standardbreds is related to the ability of muscle to produce energy by use of anaerobic glycolysis. (Am J Vet Res 1997;58:167–170)
Use of dew-point hygrometry, direct sweat collection, and measurement of body water losses to determine sweating rates in exercising horses
Authors: Kingston Janene K. , Geor Raymond J. , McCutcheon L. Jill
Published: January 2024

Objective

To compare dew-point hygrometry, direct sweat collection, and measurement of body water loss as methods for determination of sweating rate (SR) in exercising horses.

Animals

6 exercise-trained Thoroughbreds.

Procedure

SR was measured in 6 horses exercising at 40% of the speed that elicited maximum oxygen consumption for 45 km, with a 15-minute rest at the end of each 15-km phase. Each horse completed 2 exercise trials. Dew-point hygrometry, as a method of local SR determination, was validated in vitro by measurement of rate of evaporative water loss. During exercise, local SR was determined every 10 minutes by the following 2 methods: (1) dew-point hygrometry on the neck and lateral area of the thorax, and (2) on the basis of the volume of sweat collected from a sealed plastic pouch attached to the lateral area of the thorax. Mean whole body SR was calculated from total body water loss incurred during exercise.

Results

Evaporation rate measured by use of dewpoint hygrometry was significantly correlated (r2 = 0.92) with the actual rate of evaporative water loss. There was a similar pattern of change in SR measured by dew-point hygrometry on the neck and lateral area of the thorax during exercise, with a significantly higher SR on the neck. The SR measured on the thorax by direct sweat collection and by dew-point hygrometry were of similar magnitude. Mean whole body SR calculated from total body water loss was not significantly different from mean whole body SR estimated from direct sweat collection or dew-point hygrometry measurements on the thorax.

Conclusions

Dew-point hygrometry and direct sweat collection are useful methods for determination of local SR in horses during prolonged, steady-state exercise in moderate ambient conditions. Both methods of local SR determination provide an accurate estimate of whole body SR. (Am J Vet Res 1997;58:175–181)
Pregnancy-associated changes in material properties of the third metacarpal cortical bone in mares
Authors: Hawkins Dan L. , Stover Susan M.
Published: January 2024

Objective

To investigate the effect of late gestation, age, and parity on material properties of third metacarpal (MCIII) cortical bone in mares.

Animals

8 healthy mares (treatment group) that died or were euthanatized within 24 hours after parturition because of foaling complications and 6 age-matched, healthy, nonpregnant mares (control group).

Procedures

After random assignment for mechanical testing and microradiography, the dorsal half of transverse mid-diaphyseal sections of each MCIII bone was divided into lateral, dorsal, and medial regions. Cylinders of bone from each of the 3 regions were tested in compression in a single cycle to failure. Contact microradiographic views were taken of 100-µm-thick sections prepared from methylmethacrylate-embedded transverse dorsal region specimens, which were further divided into periosteal, intracortical, and endosteal regions for assessment of bone mineral density and porosity.

Results

Postpartum mares had lower yield strain in the dorsal and medial regions and failure strain in the medial region. Increasing parity was associated with decreasing elastic modulus in the dorsal region and yield stress and failure stress in the lateral region. Age and parity were positively correlated (r = 0.865; P = 0.0001), but significant correlations were not found between treatment group and age or between treatment group and parity. Increasing age and parity were associated with increasing porosity in the periosteal region.

Conclusions and Clinical Relevance

On the basis of the material properties evaluated for MCIII cortical bone in late pregnancy, any increased risk for fractures in mares in late gestation may be related to parity or age or both, and less likely to pregnancy per se. (Am J Vet Res 1997;58:182–187)
Effects of anesthesia of the palmar digital nerves on kinematic gait analysis in horses with and without navicular disease
Authors: Keegan Kevin G. , Wilson Daniel J. , Wilson David A. , Frankeny Rebecca L. , Loch Wayne E. , Smith Bryan
Published: January 2024

Objective

To determine the effect of local anesthesia of the palmar digital nerves on forelimb kinematics in Quarter Horses with and without navicular disease.

Animals

12 adult Quarter Horses; 5 clinically normal (sound) and 7 with navicular disease.

Procedure

Kinematic measurements were made on adult horses trotting on a treadmill, before and after palmar digital nerve block (PDNB). Twenty-three displacement, joint angle, and temporal gait measurements of the right forelimb and head were made for 5 strides in each horse. Initial (before local anesthesia) right forelimb measurements were obtained after a left forelimb PDNB. Kinematic measurements were compared before and after PDNB of the right forelimb by multiple ANOVA with an α = 0.05, adjusted for posthoc comparisons by Bonferroni correction.

Results

In sound horses, the only significant change in kinematic measurements after PDNB nerve block was in the maximum extension of the metacarpophalangeal joint at mid-stance, which was decreased by an angle of 2°. In horses with navicular disease, mean maximum extension of the metacarpophalangeal joint during stance phase and maximum flexion of the carpal joint during swing phase were significantly increased after PDNB. Also, total stance phase, cranial stance phase, and breakover durations were significantly shorter. In horses with navicular disease, differences between minimum head heights during stance phase of each forelimb and total vertical head excursion during a complete stride were significantly smaller after PDNB.

Conclusion

Several kinematic measurements of gait can be used to determine improvement of lameness in horses with navicular disease after PDNB block while trotting on a treadmill. (Am J Vet Res 1997; 58:218–223)
Effect of amount and type of dietary fiber on food intake in energy-restricted dogs
Authors: Butterwick R. F. , Markwell P. J.
Published: January 2024

Objective

To evaluate the effect of adding different amounts of insoluble (IF) or soluble (SF) dietary fiber to a commercial diet formulated for weight reduction on satiety and perception of hunger in dogs.

Animals

6 adult dogs.

Procedure

Test diets included 2 low-fiber control diets (CL1 and CL2), 2 diets with increased amount of IF (IF1 and IF2), and 2 diets with increased amount of SF (SF1 and SF2). Each test diet was fed for 12 days to 6 dogs in a Latin square design, and in amounts that correspond to the food allowance recommended for weight reduction. Behavioral characteristics of dogs were recorded for 30-minute periods after introduction of test diets. On 2 occasions during each test period, exactly 3 hours after feeding of the test diet, dogs were given a challenge meal consisting of a standard commercial canned dog food ad libitum. At the end of each 12-day feeding period, all dogs entered a 6-day washout period in which they were offered a standard commercial canned dog food ad libitum.

Results

Diet had no significant effect on intake of the challenge meal, intake of food during the subsequent washout period, or perception of hunger, as represented by behavioral characteristics during the 30-minute period after presentation of test diets. In addition, diet had no significant effect on percentage of weight loss.

Conclusions

Inclusion of high amounts of IF or SF in a commercial low-energy diet has no apparent beneficial effects on satiety when fed to dogs on an energy intake regimen corresponding to allowances for weight reduction. (Am J Vet Res 1997;58:272–276)
Efficacy of doramectin for treatment of experimentally induced infection with gastrointestinal nematodes in calves
Authors: Couvillion C. Edward , Pote Linda M. W. , Siefker Carla , Logan Nigel B.
Published: January 2024

Objective

To determine the efficacy of injectable doramectin against experimentally induced infections with adult and larval (L4) stages of gastrointestinal nematodes in calves.

Procedures

In each experiment, between 20 (experiments 1 and 2) and 30 (experiment 3) parasite-free yearling calves were selected and allotted to groups of 10/group. All calves received oral inoculation of the following infective larval stages of these nematode species: Cooperia onchophora, C punctata, C zurna-bada, Cooperia spp, Haemonchus placei, Nematodirus helvetianus, Oesophagostomum radiatum, Ostertagia ostertagi, Trichostrongylus axei and T colubriformis. Infections or treatments were timed so that, by day of treatment, the population of each parasite species had matured to the stage to be tested (adult or L4). On day of treatment, calves received doramectin (200 µg/kg of body weight, SC), and infected nonmedicated control calves received saline solution SC at the same time. All calves were slaughtered at least 14 days after treatment.

Results

Efficacy against the following adult and L4 species was ≥ 99%: C onchophora, C punctata, C zurnabada, Cooperia spp, H placei, Oes radiatum, O ostertagi, and T colubriformis. Doramectin was also 100% efficacious against the L4 stage of T axei. Efficacy against the adult and L4 stages of N helvetianus was 9.6 and 77.4 to 83.3%, respectively.

Conclusions

Doramectin, at a dosage of 200 µg/kg, is effective in controlling the prevalent gastrointestinal nematodes (adult and L4 stages) found in naturally infected calves.

Clinical Relevance

Doramectin, a new anthelmintic, was effective against recent field strains of the most prevalent gastrointestinal parasites found in cattle in the United States, and could provide another alternative for control of these parasites, (Am J Vet Res 1997;58:282–285)
Safety and immunogenicity of Brucella abortus strain RB51 vaccine in pregnant cattle
Authors: Palmer Mitchell V. , Olsen Steven C. , Cheville Norman F.
Published: January 2024

Objective

To determine the safety and immunogenicity of Brucella abortus strain RB51 as a vaccine in pregnant cattle.

Animals

12 Polled Hereford heifers obtained from a brucellosis-free herd and bred on site at 16 months of age to a brucellosis-free bull.

Procedure

Pregnant heifers were vaccinated at 6 months’ gestation with 109 colony-forming units of B abortus strain RB51 (n = 5), 3 × 108 colony-forming units of B abortus strain 19 (n = 5), or sterile pyrogen-free saline solution (n = 2). Samples were periodically collected for serologic testing and lymphocyte blastogenesis assays. At full gestation, heifers were euthanatized and specimens were collected for bacteriologic culture, histologic analysis, and lymphocyte blastogenesis assay, using various antigenic stimuli.

Results

None of the strain RB51- or strain 19-vaccinates aborted or had gross or microscopic lesions at necropsy that were consistent with brucellosis. Maternal blood mononuclear cells from strain RB51- and strain 19-vaccinates had proliferative responses to γ-irradiated strain RB51 and strain 19 that were greater than responses by cells from nonvaccinated controls. In contrast, maternal superficial cervical lymph node cells from strain 19-vaccinates had proliferative responses to γ-irradiated strain RB51 or strain 19 bacteria greater than those of cells from RB51-vaccinates and nonvaccinated controls. None of the heifers vaccinated with strain RB51 developed antibodies detected by use of the standard tube agglutination test, but all developed antibodies to strain RB51 that reacted in a dot ELISA, using irradiated strain RB51 as antigen.

Conclusions

Pregnant cattle can be safely vaccinated with strain RB51 without subsequent abortion or placentitis. Furthermore, strain RB51 is immunogenic in pregnant cattle, resulting in humoral and cell-mediated immune responses, but does not interfere with serologic diagnosis of field infections. (Am J Vet Res 1997;58:472–477)
Effects of certain vasoactive agents on the long-term pattern of blood pressure, heart rate, and motor activity in cats
Authors: Brown Scott A. , Langford Kimberly , Tarver Stacy
Published: January 2024

Objective

To determine whether a diurnal pattern exists in cardiovascular variables and motor activity, and whether pharmacologic agents that decrease (angiotensin converting enzyme inhibitor) or increase (Nω-nitro-L-arginine methyl ester [L-NAME]) blood pressure alter the pattern.

Animals

6 clinically normal cats.

Procedure

Radiotelemetric implants were used to measure systemic arterial pressure, heart rate, and motor activity in conscious cats maintained in cages. Measurements were obtained during absence of treatment (control), treatment with dietary salt restriction plus an inhibitor of angiotensin converting enzyme (2.5 mg of lisinopril, PO, daily) and treatment with an inhibitor of nitric oxide production (0.1% L-NAME in the drinking water).

Results

A diurnal pattern in arterial pressure and motor activity was observed, with highest values obtained during presence of laboratory personnel. Mean values for arterial pressure obtained during light hours varied from those obtained during darkness (P < 0.05), but by < 3 mm of Hg. Dietary sodium restriction did not have an appreciable effect on arterial pressure, but the combined administration of a low sodium diet plus lisinopril decreased (P < 0.05) measured indices of arterial pressure. Administration of L-NAME increased arterial pressure (P < 0.05) and altered its diurnal pattern.

Conclusions

Although a diurnal pattern of arterial pressure was observed, variations were mostly associated with presence of human beings. Administration of L-NAME, but not lisinopril, altered this diurnal pattern.

Clinical Relevance

Factors that modify arterial pressure may alter the diurnal pattern of cardiovascular variables. In measuring arterial pressure in cats, the effects of human contact may artifactually increase such variables. (Am J Vet Res 1997;58:647–652)
Effect of sodium bicarbonate administration on blood constituents of horses
Authors: Rivas Luis J. , Hinchcliff Kenneth W. , Kohn Catherine W. , Sams Richard A. , Chew Dennis J.
Published: January 2024

Objective

To describe changes in blood constituents of horses after oral and IV administration of sodium bicarbonate (NaHCO3), and to determine whether the changes are dose dependent.

Animals

6 adult Standardbred mares.

Procedure

3 oral doses (1,500, 1,000, and 250 mg/kg of body weight) or 1 intravenous dose (250 mg/kg, 5% solution) of NaHCO3 in 3 L of water, or water (3 L orally), were given to the mares; then changes in blood constituents were measured. Access to food and water was denied during the experiment. Blood samples were collected immediately before treatment and at hourly intervals for 12 hours after treatment, and were analyzed for blood gas tensions; serum osmolality; serum sodium, potassium, chloride, and creatinine concentrations; PCV; and total solids concentration in plasma.

Results

All NaHCO3 treatments induced significant (P < 0.05) metabolic alkalosis, hypernatremia, hypokalemia, and hyperosmolality for at least 8 hours. In mares given the 1,500- and 1,000-mg doses of NaHCO3 orally, hypercapnia persisted for at least 12 hours, whereas hypercapnia lasted 2 hours in mares given the 250-mg dose orally or IV (P < 0.05). A tendency for reduction in PCV, proteins in plasma concentration, and serum concentration of chloride was observed 1 hour after IV administered doses of NaHCO3.

Conclusions

Oral or IV administration of NaHCO3 (≥ 250 mg/kg) to resting horses without ad libitum access to water induces significant and persistent acidbase and electrolyte changes. (Am J Vet Res 1997;58:658–663)