bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biomechanics of the thoracolumbar vertebral column of dogs during lateral bending
Authors: Schulz K. S. , Waldron D. R. , Grant J. W. , Shell L. , Smith G. , Shires P. K. 
Published: January 2024

Abstract

Objective
To study biomechanical characteristics of the normal and surgically altered canine thoracolumbar vertebral column to determine the effects of surgery and trauma on lateral stability.

Animals
The T13-L1 vertebral motion units of 48 mixed-breed dogs were dissected free of surrounding musculature and prepared for biomechanical testing by cross-pinning the vertebral bodies and mounting in polymethylmethacrylate.

Procedure
Normal and surgically altered spinal specimens were subjected to lateral bending. The mean slope of the bending moment versus angular displacement curve and the load to failure were compared between treatment groups and significance was determined by the method of least squares (P < 0.05). Specimens were surgically altered by facetectomy, lateral fenestration, diskectomy, and combinations of these procedures. Each specimen was subjected to lateral bending to failure at a rate of 2.5 cm/min in a swing arm bending jig designed to simulate 4-point bending and subject the specimen to pure bending.

Results
Only specimens undergoing diskectomy had a significant decrease in slope and load at failure. Unilateral and bilateral facetectomies and fenestration induced a nonsignificant decrease in stiffness, compared with control specimens.

Conclusions
Fenestrations and facetectomies do not appear to increase the risk of injury to the canine thoracolumbar spinal cord during lateral bending.

Clinical Relevance
Fenestrations and facetectomies, as used in routine laminectomies, may be performed without concern for significant destabilization of the spine in lateral bending; however, it is possible that thoracolumbar spinal fractures involving only the vertebral body may significantly destabilize the spine in all modes of bending. (Am J Vet Res 1996;57:1228-1232)
Neuromuscular effects of toxins isolated from Southern Prickly Ash (Zanthoxylum clava-herculis) bark
Authors: Bowen J. M. , Cole R. J. , Bedell D. , Schabdach D. 
Published: January 2024

Abstract

Objective
To define the nature and mechanisms of neuromuscular effects of toxic principles in bark of Southern Prickly Ash tree (Zanthoxylum clava-herculis) that might contribute to its clinical toxicity in cattle.

Animals
31 rats, 1 dog, and 4 rabbits.

Procedures
Extracts were prepared from bark samples, using 2 extraction methods. Contractile responses, resting potentials, miniature end-plate potentials (MEPP), and end-plate potentials of rat phrenic nerve-hemidiaphragm preparations were recorded. Blood pressure and contractile responses of the cranial tibial muscle to nerve stimulation were recorded in an anesthetized dog. Topical anesthetic activity in rabbits was determined by evaluation of the corneal reflex.

Results
One extract usually stimulated muscle contractile response, whereas the other inhibited this response when evoked by nerve stimulation, but not when evoked by direct muscle stimulation. Inhibitory extract (Xl) had a hypotensive effect, but lacked topical anesthetic activity and effect on resting potentials. This extract also reduced amplitude of MEPP and end-plate potentials, but did not affect their time course or the frequency of MEPP. Stimulatory extract was not active in presence of neuromuscular blocking agent tubocurarine.

Conclusion
Active principles in Southern Prickly Ash extracts appear to exert their action on neuromuscular transmission probably through blockade of postjunctional, end-plate receptors (Xl) or enhanced release of neurotransmitter (stimulatory extract).

Clinical Relevance
Signs of clinical toxicity in cattle were best correlated with effects of Xl, which can be antagonized by Ca2+ and neostigmine. (Am J Vet Res 1996;57:1239-1244)
Effect of antibodies to staphylococcal α and β toxins and Staphylococcus aureus on the cytotoxicity for and adherence of the organism to bovine mammary epithelial cells
Authors: Cifrian Eduardo , Guidry Albert J. , O'Brien Celia N. , Marquardt Warren W. 
Published: January 2024

Abstract

Objective
To determine the effect of antibodies to staphylococcal α and β toxins and Staphyloco ccus aureus on the toxicity for and adherence of S aureus to bovine mammary epithelial cells.

Sample Population
Cultured bovine mammary epithelial cells and Staphylococcus aureus obtained from a cow with mastitis.

Procedure
Cultured bovine epithelial cells were incubated with antisera to α and β toxins of S aureus and culture supernatant; cell damage and S aureus adherence to cells were measured.

Results
Antisera to α, β, and α + β toxins inhibited cytotoxicity of S aureus culture supernatant. Antiserum to α + β toxin was the most effective inhibitor of cytotoxicity and antiserum to β toxin was the least effective. All 3 antisera decreased the percentage of S aureus adhered to the mammary epithelial cell monolayers and numbers of organisms per cluster of adhered bacteria. In this study, antisera to α and α + β toxins decreased the number of S aureus clusters per dish, but antiserum to β toxin had no significant effect. Antiserum to α + β toxin decreased the percentage of epithelial cells with adhered S aureus, but neither antiserum to α nor β toxin had significant effect. Antiserum to S aureus decreased the percentage of S aureus adhered, number of clusters per dish, number of organisms per cluster, and percentage of epithelial cells with S aureus adhered.

Conclusions
Antibodies to staphylococcal α and β toxins inhibit adherence to and cytotoxicity of S aureus for bovine mammary epithelial cells, and antibodies to S aureus inhibit adherence of S aureus to bovine mammary epithelial cells. (Am J Vet Res 1996;57:1308-1311)
Pulmonary vascular pressures of strenuously exercising Thoroughbreds after administration of phenylbutazone
Authors: Manohar Murli , Goetz Thomas E. , Griffin Richard , Sullivan Eileen 
Published: January 2024

Abstract

Objective
To determine the effects of phenylbutazone administration on heart rate and right atrial and pulmonary vascular pressures in Thoroughbreds during rest and during exercise performed at maximal heart rate.

Animals
7 healthy, exercise-conditioned Thoroughbreds.

Procedure
Horses were studied on 3 occasions: without medication (control), after IV administration of phen-ylbutazone (4.4 mg/kg of body weight) at 12-hour intervals for 2 days and a final dose given 1 hour before exercise, and after IV administration of phenylbutazone for 2 days in the same manner, but with the final dose given 24 hours before exercise. Horses were studied at rest and during exercise performed at maximal heart rate on a treadmill. Right atrial and pulmonary vascular pressures were measured with catheter-tip manometers referenced at the point of the shoulder.

Results
We did not detect significant differences in heart rate or right atrial and pulmonary vascular pressures among values recorded when horses were not given medication and values recorded when phenylbutazone was administered by either regimen. Exercise-induced pulmonary hemorrhage occurred in 6 of the 7 horses re-gardless of whether phenylbutazone was administered or the dosage regimen used.

Conclusions
In these Thoroughbreds, phenylbutazone treatment did not modify heart rate or right atrial and pulmonary vascular pressures at rest or during exercise capable of eliciting exercise-induced pulmonary hemorrhage. Thus, because phenylbutazone is a potent inhibitor of cyclooxygenase, prostaglandins probably do not play a role in mediating exercise-induced pulmonary hypertension in horses.

Clinical Relevance
Phenylbutazone administration did not modify the pulmonary capillary hypertension in the strenuously exercising Thoroughbreds, and therefore, is unlikely to alter the prevalence or severity of exercise-induced pulmonary hemorrhage in Thoroughbred race-horses. (Am J Vet Res 1996;57:1354-1358)
Effects of ozone and airway inflammation on glutathione status and iron homeostasis in the lungs of horses
Authors: Mills P. C. , Roberts C. A. , Smith N. C. 
Published: January 2024

Abstract

Objective
To investigate the effects of ozone and airway inflammation on indices of oxidant injury in horses.

Animals
5 clinically normal horses and 25 horses referred for poor performance

Procedure
Blood, tracheal wash, and bronchoalveolar lavage fluid samples were collected before and after ozone exposure (n = 5) or from clinical cases (n = 25), and were analyzed for reduced glutathione (GSH), glutathione disulfide (GSSG), and free and total iron (Fe) values. A scor ing system (0 to 5) was used to assess airway inflammation on the basis of clinical signs and cytologic analysis of the tracheal wash and bronchoalveolar lavage fluid samples.

Results
Ozone induced significant (P < 0.05) increases in GSH (195.4 ± 68.5 μM, GSSG (19.4 ± 6.4 μM). and free (25.5 ± 16.1 μM) and total (93.1 ± 13.4 μM) Fe values in the pulmonary epithelial lining fluid, compared with preozone samples (49.2 ± 18.6, 2.4 ± 1.2, 0.0, and 33.1 ± 5.9 μM, respectively). The presence of airway inflammation (19/25) was associated with high GSSG and free and total Fe, but not GSH, values in epithelial lining fluid, compared with values for clinically normal horses (6/25). There were no differences in the systemic values of GSH, GSSG, and free and total Fe between any of the groups. A strong correlation (r = 0.84; P < 0.001) existed between inflammation score and the glutathione redox ratio (GSSG/IGSH + GSSG]) in the 25 horses admitted for clinical examination

Conclusions
Oxidant injury in the lung will induce changes in the glutathione status and Fe homeostasis that could affect pathogenesis of the disease.

Clinical Relevance
Measurement of indices of oxidant injury may be useful in the diagnosis of airway inflammation and the response to inhaled oxidants. (Am J Vet Res 1996;57:1359-1363)
Postimplantation increase in plasma fibrinogen concentration with increase in relaxin concentration in pregnant dogs
Authors: Concannon Patrick W. , Gimpel Terry , Newton Lucy , Castracane V. Daniel 
Published: January 2024

Abstract

Objective
To determine time courses of pregnancy-related changes in plasma fibrinogen, serum relaxin, and serum C-reactive protein-like immunoreactivity (CRP-LI) concentrations in pregnant and nonpregnant dogs.

Animals
16 pregnant and 13 nonpregnant Beagles, 6 pregnant Beagles, and 3 pregnant and 3 nonpregnant dogs of other breeds.

Procedure
Fs'brinogen was measured by nephelometric centrifugal analysis of light scatter in plasma samples of all dogs, and CRP-LI was measured by fluorescence immunoassay in selected sera from 10 pregnant and 10 nonpregnant dogs. Relaxin was measured in selected sera from 7 pregnant and 7 nonpregnant dogs.

Results
During pregnancy, fibrinogen concentration increased between days 21 and 30 after the luteinizing hormone surge, and was > 280 mg/dl between days 29 and 50 in 84 of 86 samples, with peak values 539 ± 29 mg/dl higher (P < 0.01) than those in nonpregnant dogs (188 ± 8 mg/dl), higher values from days 21 to 50 (P < 0.01) than those in nonpregnant dogs, and values similar to those in nonpregnant dogs after day 50. Relaxin concentration was increased from days 26 to 30 and 0 to 4 days after fibrinogen concentration increased in pregnant dogs, and was not detectable in nonpregnant dogs. The CRP-LI concentration was higher in pregnant dogs at days 26 to 50, but values were inconsistent within and among dogs, and near the limit of sensitivity of the assay.

Conclusions
Concentration of the acute-phase reactant protein fibrinogen increases after day 20 following implantation in dogs, at or just before the pregnancy-specific increase in relaxin concentation from days 26 to 30, and persists until day 50.

Clinical Relevance
Fibrinogen assay may be useful for pregnancy diagnosis in dogs. (Am J Vet Res 1996;57:1382–1385)
In vitro determination of equine third metacarpal bone unloading, using a full limb cast and a walking cast
Authors: Brommer Harold , Back Wim , Schamhardt Henk C. , Rijkenhuizen Astrid B. M. , Barneveld Ab 
Published: January 2024

Abstract

Objective
To improve fracture treatment, in vitro experiments were performed to study the influence of a full limb cast and a walking cast on the loading regimen of bones in the distal portion of the equine forelimb.

Animals
6 forelimbs of 6 Shetland ponies.

Procedure
Loading of the third metacarpal bone was considered a representative measure for distal limb loading. Electrical resistance rosette strain gauges were attached to the dorsal, palmar, medial, and lateral surfaces of the midshaft of this bone in 6 forelimbs of 6 Shetland ponies. The limbs were tested in a pneumatic loading device to a maximal load of 1,500 N.

Results
Both casts decreased the amount of compressive forces acting on the metacarpal bone. Application of a full limb cast resulted in a variable and eccentric decrease, remaining strains ranging from 84 to 7% of the baseline value. A walking cast was superior in that it gave a centric and more uniform reduction of compressive loading to <11 % of the baseline value. Moreover, a walking cast neutralized the bending and torsion components of the loading.

Conclusion
This study confirmed the clinical experience that a walking cast creates more reliable and favorable conditions for healing of fractures than does a full limb cast. (Am J Vet Res 1996;57:1386-1389)
Resting energy expenditure in dogs with nonhematopoietic malignancies before and after excision of tumors
Authors: Ogilvie Gregory K. , Walters Lisa M. , Salman M. D. , Fettman Martin J. 
Published: January 2024

Abstract

Objective
To determine whether apparently resting dogs with nonhematopoietic malignancies have increased resting energy expenditure (REE), compared with clinically normal dogs.

Animals
46 client-owned dogs with nonhematopoietic malignancies and 30 client-owned dogs that were clinically normal.

Procedure
Apparently resting, client-owned dogs with nonhematopoietic malignancies before (n = 46) and 4 to 6 weeks after (n = 30) surgical removal of tumors were compared with apparently resting, clinically normal, client-owned dogs (n = 30). An open flow indirect calorimetry system was used to determine the following: rate of oxygen consumption (ml/min/kg of body weight); rate of carbon dioxide production (mls/min/kg), REE (kcal/kg/d), and respiratory quotient. Because of the wide range of body weight, REE and oxygen consumption were also expressed per kg of body weight0.75.

Results
Surgical removal of the tumor did not significantly alter any of the variables measured when all dogs with tumors were assessed as a single group, or when the dogs were divided on the basis of having the following types of tumors: carcinomas and sarcomas, osteosarcomas, and mammary adenocarcinomas. None of the data obtained prior to surgical treatment from any of the dogs grouped by tumor type were significantly different from clinically normal dogs.

Conclusions
REE (54.4 ± 16 kcal/kg/d or 125 ± 19 kcal/kg0.75/d) and, presumably, caloric requirements of dogs with nonhematopoietic malignancies are not significantly different from those obtained from clinically normal dogs (53.9 ± 16 kcal/kg/d or 116 ± 32 kcal/kg0.75/d). Furthermore, these variables do not change significantly when the tumor is excised and the dog is reassessed after 4 to 6 weeks.

Clinical Relevance
Knowledge that REE in dogs with solid tumors is not significantly different from REE of clinically normal dogs may be of value when planning nutritional treatment for dogs with nonhematopoietic malignancies. (Am J Vet Res 1996;57:1463-1467)
Lack of serum antibodies against glycoprotein E in pseudorabies virus-immune pigs infected with wild-type virus
Authors: Jacobs Liesbeth , Kimman Tjeerd G. , Bianchi Andre 
Published: January 2024

Abstract

Objective
To examine whether pigs with solid immunity against pseudorabies virus (PRV) could harbor latent infection with wild-type PRV without developing antibodies against glycoprotein E (gE), which is used as a marker protein to differentiate pigs that have been vaccinated from pigs infected with wild-type PRV.

Animals
Specific-pathogen-free pigs that were seronegative for antibodies to PRV.

Procedure
Oropharyngeal swab specimens were collected, and virus content was measured. Serum samples were obtained 1 week before and 2 and 4 weeks after challenge exposure. Four weeks after challenge exposure, pigs were slaughtered; various tissues were collected for virus isolation, and DNA was analyzed by polymerase chain reaction.

Results
Of the intranasally inoculated pigs, only 1 pig shed virus (for 1 day) but none developed antibodies directed against gE. Of the inoculated IM pigs, 3 pigs shed virus (for several days) and 5 developed antibodies directed against gE. One pig did not shed virus and did not develop detectable gE antibodies. However, variable amounts of wild-type virus DNA were detected in various tissues.

Conclusions
Immunized pigs can be infected with wild-type PRV without being detected by the gE-specific ELISA, which is routinely used to discriminate between infected and vaccinated pigs. The implication for eradication programs is that these pigs might be a source of new outbreaks. (Am J Vet Res 1996;57:1525–1528)
Pharmacokinetics, effects on renal function, and potentiation of atracurium-induced neuromuscular blockade after administration of a high dose of gentamicin in isoflurane-anesthetized dogs
Authors: Martinez Elizabeth A. , Mealey Katrina L. , Wooldridge Anne A. , Mercer Dana E. , Cooper Jonathan , Slater Margaret R. , Hartsfield Sandee M. 
Published: January 2024

Abstract

Objective
To determine pharmacokinetics, renal effects, and effect on atracurium-induced neuromuscular blockade of a high dose of gentamicin in isoflurane-anesthetized dogs.

Animals
6 healthy, adult, mixed-breed dogs, anesthetized twice and receiving gentamicin (6 mg/kg of body weight, IV) or saline solution.

Procedure
Blood samples were collected before and at intervals after gentamicin administration. Pharmacokinetic values were evaluated by use of multivariant stepwise linear regression analysis. Gentamicin-induced renal changes were assessed by comparing pretreatment and 12- to 24-hour posttreatment values for serum urea nitrogen, serum creatinine, urine creatinine-to-γ-glutamyltransferase ratio, and urinalysis. Neuromuscular blockade, maintained by atracurium infusion, was assessed, using the train-of-four response. At stable 50% depression of first twitch (T1) gentamicin or saline solution was given. Before and at posttreatment intervals for 60 minutes, T1% and fourth twitch-to-T1 ratio were recorded. The infusion was discontinued and 50 to 75% T1 recovery time was recorded. At 75% T1, edrophonium (0.5 mg/kg) was administered IV.

Results
Mean values for volume of distribution and clearance were 0.263 L/kg and 2.0 ml/min/kg, respectively. Mean maximal serum concentration of gentamicin was 46.4 μg/ml. Pre and posttreatment values for serum urea nitrogen, serum creatinine, urine creatinine-to-γ-glutamyltransferase ratio, and other urine analytes were not significantly different. Mean (± SD) values for T1% and fourth twitch-to-T1 ratio decreased significantly after gentamicin (depression was maximal at 5 minutes). Recovery time (50 to 75% T1) was not different between groups. Edrophonium restored twitch to baseline.

Conclusions
Mean values for apparent volume of distribution and total body clearance of gentamicin were similar to values in unanesthetized dogs. Mean maximal serum concentration of gentamicin was greater than that in unanesthetized dogs. Renal function was unaffected. Gentamicin potentiated atracurium-induced neuromuscular blockade, but did not affect recovery time. (Am J Vet Res 1996;57:1623–1626)
Comparative pharmacokinetics of phenylbutazone and its metabolite oxyphenbutazone in clinically normal horses and donkeys
Authors: Mealey Katrina L. , Matthews Nora S. , Peck Kenneth E. , Ray Allen C. , Taylor T. S. 
Published: January 2024

Abstract

Objective
To compare plasma disposition of phenylbutazone and its metabolite oxyphenbutazone after IV administration of phenylbutazone in horses and donkeys.

Animals
4 clinically normal horses and 6 clinically normal donkeys.

Procedure
Blood samples were collected from each animal at time 0 (before) and 5, 10, 20, 30, 45, 60, 90, 120, 180, 240, 300, 360, and 480 minutes after IV administration of a bolus dose of phenylbutazone. Serum was analyzed in triplicate by use of high-performance liquid chromatography for determination of phenylbutazone and oxyphenbutazone concentrations. The serum concentration-time curve for each horse and donkey was analyzed separately to estimate model-independent pharmacokinetic variables.

Results
Significant differences were found in several pharmacokinetic variables of phenylbutazone and oxyphenbutazone in horses, compared with donkeys. Mean total body clearance of phenylbutazone in horses was fivefold less than that in donkeys (29.3 and 170.3 ml/kg/h, respectively). Mean values for area under the curve and mean residence time in horses (118.3 µg/h/ml and 3.6 hours, respectively) were significantly greater than values in donkeys (28.3 µg/h/ml and 1.7 hours, respectively). Mean values for apparent volume of distribution at steady state were not significantly different between horses and donkeys. For oxyphenbutazone, mean time to peak concentration in donkeys was significantly less than that in horses (1.6 and 6.4 hours, respectively).

Conclusion
Phenylbutazone clearance in donkeys was higher than that in horses, and appearance of the metabolite oxyphenbutazone in serum was more rapid in donkeys than in horses, indicating that hepatic metabolism of phenylbutazone is more rapid in donkeys than in horses.

Clinical Relevance
Because serum concentration of phenylbutazone after single IV bolus administration (4.4 mg/kg of body weight) decreases more rapidly in donkeys, compared with horses, phenylbutazone may require more frequent administration in donkeys to achieve therapeutic efficacy. (Am J Vet Res 1997;58:53–55)