bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacokinetics and clinical effects of a subanesthetic continuous rate infusion of ketamine in awake horses
Authors: Fielding C. Langdon , Brumbaugh Gordon W. , Matthews Nora S. , Peck Kenneth E. , Roussel Allen J.
Published: September 2006

Objective—To determine the pharmacokinetics and clinical effects of a subanesthetic, continuous rate infusion of ketamine administered to healthy awake horses.

Animals—8 adult horses.

Procedures—Ketamine hydrochloride was administered to 2 horses, in a pilot study, at rates ranging from 0.4 to 1.6 mg/kg/h for 6 hours to determine an appropriate dose that did not cause adverse effects. Ketamine was then administered to 6 horses for a total of 12 hours (3 horses at 0.4 mg/kg/h for 6 hours followed by 0.8 mg/kg/h for 6 hours and 3 horses at 0.8 mg/kg/h for 6 hours followed by 0.4 mg/kg/h for 6 hours). Concentration of ketamine in plasma, heart rate, respiratory rate, blood pressure, physical activity, and analgesia were measured prior to, during, and following infusion. Analgesic testing was performed with a modified hoof tester applied at a measured force to the withers and radius.

Results—No signs of excitement and no significant changes in the measured physiologic variables during infusion rates of 0.4 and 0.8 mg of ketamine/kg/h were found. At 6 hours following infusions, heart rate and mean arterial pressure were decreased, compared with preinfusion measurements. An analgesic effect could not be demonstrated during or after infusion. Pharmacokinetic variables for 0.4 and 0.8 mg/kg/h infusions were not significantly different.

Conclusions and Clinical Relevance—Ketamine can be administered to awake horses at 0.4 or 0.8 mg/kg/h without adverse behavioral effects. The observed pharmacokinetic values are different than those reported for single-dose IV bolus administration of this drug.
Effects of increasing infusion rates of dopamine, dobutamine, epinephrine, and phenylephrine in healthy anesthetized cats
Authors: Pascoe Peter J. , Ilkiw Jan E. , Pypendop Bruno H.
Published: September 2006

Objective—To determine the cardiopulmonary effects of increasing doses of dopamine, dobutamine, epinephrine, and phenylephrine and measure plasma concentrations of norepinephrine, epinephrine, and dopamine in cats anesthetized with isoflurane.

Animals—6 healthy adult cats.

Procedures—Each cat was anesthetized with isoflurane (1.5 X minimum alveolar concentration) on 4 occasions. Cardiopulmonary measurements were obtained after a 30-minute stabilization period; 20 minutes after the start of each infusion dose; and 30, 60, and 90 minutes after the infusion was discontinued. Cats received 5 progressively increasing infusions of epinephrine or phenylephrine (0.125, 0.25, 0.5, 1, and 2 μg/kg/min) or dobutamine or dopamine (2.5, 5, 10, 15, and 20 μg/kg/min). The order of treatment was randomly allocated.

Results—All 4 treatments increased oxygen delivery. Heart rate (HR) increased during administration of all drugs except phenylephrine, and mean arterial pressure increased during administration of all drugs except dobutamine. A progressive metabolic acidosis was detected, but whole-blood lactate concentration only increased during administration of epinephrine and dobutamine. Systemic vascular resistance index increased during administration of phenylephrine, decreased during administration of dobutamine, and remained unchanged during administration of dopamine and epinephrine. A positive inotropic effect was detected with all treatments.

Conclusions and Clinical Relevance—During anesthesia in cats, administration of dopamine, dobutamine, and epinephrine may be useful for increasing cardiac output, with dopamine having the most useful effects. Administration of phenylephrine increased cardiac and systemic vascular resistance indexes with minimal effect on HR and may be useful for increasing mean arterial pressure without increasing HR.
Elimination behavior patterns of domestic cats (Felis catus) with and without elimination behavior problems
Authors: Sung Wailani , Crowell-Davis Sharon L.
Published: September 2006

Objective—To investigate the relationship of litter box location as it relates to cats' use of space in the house, elimination problems, and certain behaviors associated with elimination.

Sample Population—40 cats in single-cat house-holds with or without elimination behavior problems (20 cats/group).

Procedures—Camcorders were used to record the cats' behaviors at the litter box and other areas in which they eliminated during a 72-hour period. Use of space in the house was recorded by direct observation during 400 minutes of the 72-hour period. Elimination behaviors and other cat- and litter box–associated variables were compared between groups; litter box location with respect to inappropriate elimination was assessed.

Results—Litter box location did not differ between cats with and without elimination behavior problems. An inverse correlation was found between time spent sniffing and the distance of the litter box from the central core area. Cats with elimination problems spent significantly less time digging at the litter box than cats without elimination problems. There was no significant difference in the time spent pawing in litter box, sniffing, or covering excreta after elimination between the 2 groups of cats.

Conclusions and Clinical Relevance—Times spent digging in litter boxes by cats with and without elimination problems have been determined, and data suggest that actual digging times could be used as a means to test for litter preference and litter aversion. This information may also be used to identify cats with litter aversion prior to the development of an elimination problem.
Locomotor mechanics of the tölt in Icelandic horses
Authors: Biknevicius Audrone R. , Mullineaux David R. , Clayton Hilary M.
Published: September 2006

Objective—To evaluate the locomotor mechanics of the tölt in Icelandic horses.

Animals—10 adult Icelandic horses with no history of lameness.

Procedures—Force platform data were captured for 27 trials for horses ridden at a tölt in a lateral sequence single-foot gait at a steady speed from 0.89 to 5.98 m/s. Simultaneous kinematic data were obtained by tracking retroflective markers overlying the right fore- and hind limbs. These kinetic and kinematic data were combined to evaluate 3 mechanical approaches, duty factor, Froude number, and center of mass (COM) mechanics, and to evaluate the capacity to recover mechanical energies during tölting via inverse pendulum and spring-mass (bouncing) mechanics.

Results—Tölting horses had in-phase fluctuations of gravitational potential and kinetic energies of their COM and a capacity to recover mechanical energy through elastic recoil of spring elements in their limbs. These characteristics, along with Froude numbers exceeding values expected for the walk-run transition, are indicative of bouncing mechanics and, hence, most strongly ally tölting with running. Only the footfall pattern of a lateral sequence single-foot gait and low vertical excursions of the COM are more commonly associated with walking.

Conclusions and Clinical Relevance—At the tölt, horses have unique mechanical characteristics that should be understood for veterinary care. Differences in interlimb coordination between tölting and trotting mask the overall similarities in most other aspects of their locomotor dynamics.
Gentamicin concentrations in synovial fluid obtained from the tarsocrural joints of horses after implantation of gentamicin-impregnated collagen sponges
Authors: Ivester Kathleen M. , Adams Stephen B. , Moore George E. , Van Sickle David C. , Lescun Timothy B.
Published: September 2006

Objective—To determine synovial fluid gentamicin concentrations and evaluate adverse effects on the synovial membrane and articular cartilage of tarsocrural joints after implantation of a gentamicin-impregnated collagen sponge.

Animals—6 healthy adult mares.

Procedures—A purified bovine type I collagen sponge impregnated with 130 mg of gentamicin was implanted in the plantarolateral pouch of 1 tarsocrural joint of each horse, with the contralateral joint used as a sham-operated control joint. Gentamicin concentrations in synovial fluid and serum were determined for 120 hours after implantation by use of a fluorescence polarization immunoassay. Synovial membrane and cartilage specimens were collected 120 hours after implantation and evaluated histologically.

Results—Median peak synovial fluid gentamicin concentration of 168.9 μg/mL (range, 115.6 to 332 μg/mL) was achieved 3 hours after implantation. Synovial fluid gentamicin concentrations were < 4 μg/mL by 48 hours. Major histologic differences were not observed in the synovial membrane between control joints and joints implanted with gentamicin-impregnated sponges. Safranin-O fast green stain was not reduced in cartilage specimens obtained from treated joints, compared with those from control joints.

Conclusions and Clinical Relevance—Implantation of a gentamicin-impregnated collagen sponge in the tarsocrural joint of horses resulted in rapid release of gentamicin, with peak concentrations > 20 times the minimum inhibitory concentration reported for common pathogens that infect horses. A rapid decrease in synovial fluid gentamicin concentrations was detected. The purified bovine type I collagen sponges did not elicit substantial inflammation in the synovial membrane or cause mechanical trauma to the articular cartilage.
Accuracy of an oscillometric blood pressure monitor during phenylephrine-induced hypertension in dogs
Authors: McMurphy Rose M. , Stoll Melissa R. , McCubrey Raymond
Published: September 2006

Objective—To examine the agreement between direct arterial blood pressure measurements obtained from 2 arteries and indirect blood pressure measurements obtained with an oscillometric blood pressure monitor (OBPM) during normotension and phenylephrine-induced hypertension in dogs.

Animals—16 male Beagles.

Procedures—In anesthetized dogs, arterial catheters were placed in the lingual and dorsal pedal arteries for measurement of arterial blood pressure. A blood pressure cuff was placed on either the dog's fore- or hind limb and connected to an OBPM. Systolic, diastolic, and mean arterial blood pressures (SAP, DAP, and MAP, respectively) were recorded from both arteries and the OBPM every 5 minutes for 30 minutes (baseline), during a 30-minute period in which dogs received a phenylephrine infusion IV to induce hypertension, and for 30 minutes after discontinuation of the infusion. Mean differences in blood pressure values and confidence intervals were calculated to compare the indirect and direct measurement techniques.

Results—In dogs, oscillometry underestimated SAP during normotension, and the difference between oscillometric and direct measurements increased during hypertension. Oscillometry underestimated DAP, but the difference between oscillometric and direct measurements decreased during hypertension. There was close agreement among techniques for MAP determinations. Biases between direct measurements and OPBM blood pressure values measured from dogs' forelimbs or hind limbs were not significantly different.

Conclusions and Clinical Relevance—In normotensive dogs, oscillometric measurements of MAP and SAP agreed more closely with direct arterial pressure measurements than oscillometric estimates of DAP. Oscillometric measurement of MAP was accurate during both normotension and hypertension in dogs.
Comparison of digitized and conventional radiographic images for assessment of hip joint conformation in dogs
Authors: Essman Stephanie , Sherman Ashley
Published: September 2006

Objective—To determine agreement between assessments of canine hip joint conformation provided by board-certified radiologists after evaluation of digitized and conventional radiographic images.

Sample Population—200 pelvic radiographs previously evaluated by radiologists using the Orthopedic Foundation for Animals standard grading system for canine hip joint conformation.

Procedures—Each of 20 board-certified radiologists evaluated conventional and digitized pelvic radiographs from each of 200 dogs for hip joint conformation. A weighted kappa coefficient and intraclass correlation were used to determine agreement between assessments derived from digitized radiographic images and conventional radiographs and between the original Orthopedic Foundation for Animals conformation ratings and assessments derived from each image format.

Results—Overall, agreement between assessments derived from the digitized images and conventional radiographs was good, with all but 1 radiologist attaining a weighted kappa coefficient > 0.61. Intraclass correlation for each radiologist ranged from 0.75 to 0.98 (95% confidence interval, 0.67 to 0.984). On comparison of conformation assessments, 95.7% of those derived from conventional radiographs and digitized images were within 1 grade. On comparison of digitized radiographic conformation assessments and conformation ratings, 94.2% were within 1 grade. On comparison of conventional radiographic conformation assessments and conformation ratings, 92.3% were within 1 grade.

Conclusions and Clinical Relevance—The use of digitized radiographic images does not appear to impact the radiographic assessments of canine hip joint conformation made by consultant radiologists. Compared with conventional radiographs, the use of digitized radiographic images decreases storage space requirements and enables more rapid reporting of assessment results for individual dogs.
Effect of adrenalectomy on cholecystokinin-8–induced Fos-like immunoreactivity in myenteric neurons and the dorsal vagal complex in rats
Authors: Raboin Shannon J. , Gulley Stephen , Henley Sheryce C. , Chang Wai-Chu , Esdaile Alton R. , Jackson Cheryl A. , Sayegh Ayman I.
Published: September 2006

Objective—To investigate the effect of adrenalectomy on cholecystokinin-8 (CCK-8)–induced Fos-like immunoreactivity (Fos-LI) in the myenteric neurons of the dorsal vagal complex (DVC) in rats.

Animals—16 male Sprague Dawley rats.

Procedures—Rats were allocated to 1 of 2 groups and underwent adrenalectomy or a sham adrenalectomy procedure. Rats were challenged with a supraphysiologic dose of CCK-8 (40 μg/kg) or physiologic saline (0.9% NaCl) solution (0.5 mL) administered IP; after 90 minutes, rats were euthanized, and Fos-LI was quantified in the DVC (at the levels of the area postrema, nucleus tractus solitarii, and dorsal motor nucleus of the vagus) and the myenteric neurons of the duodenum and jejunum by use of a diaminobenzidine reaction enhanced with nickel. The Fos-LI–positive cells were counted by use of an automated system and manually in the DVC and intestinal samples, respectively. Counts of Fos-LI in the different hindbrain levels and myenteric neurons were compared between the adrenalectomy- and shamtreated groups and between the CCK-8– and saline solution–treated groups.

Results—After adrenalectomy, CCK-8–induced Fos-LI was attenuated only in the myenteric neurons of the duodenum.

Conclusions and Clinical Relevance—Results indicate that the adrenal gland has a role in the activation of myenteric neurons by CCK-8 in rats.
Effects of food intake and food withholding on plasma ghrelin concentrations in healthy dogs
Authors: Bhatti Sofie F. , Hofland Leo J. , van Koetsveld Peter M. , Van Ham Luc M. , Duchateau Luc , Mol Jan A. , van der Lely Aart Jan , Kooistra Hans S.
Published: September 2006

Objective—To investigate the physiologic endocrine effects of food intake and food withholding via measurement of the circulating concentrations of acylated ghrelin, growth hormone (GH), insulin–like growth factor-I (IGF-I), glucose, and insulin when food was administered at the usual time, after 1 day's withholding, after 3 days' withholding and after refeeding the next day in healthy Beagles.

Animals—9 healthy Beagles.

Procedures—Blood samples were collected from 8:30 AM to 5 PM from Beagles when food was administered as usual at 10 AM, after 1 day's withholding, after 3 days' withholding, and after refeeding at 10 AM the next day.

Results—Overall mean plasma ghrelin concentrations were significantly lower when food was administered than after food withholding. Overall mean plasma GH and IGF-I concentrations did not differ significantly among the 4 periods. Circulating overall mean glucose and insulin concentrations were significantly higher after refeeding, compared with the 3 other periods.

Conclusions and Clinical Relevance—In dogs, food withholding and food intake were associated with higher and lower circulating ghrelin concentrations, respectively, suggesting that, in dogs, ghrelin participates in the control of feeding behavior and energy homeostasis. Changes in plasma ghrelin concentrations were not associated with similar changes in plasma GH concentrations, whereas insulin and glucose concentrations appeared to change reciprocally with the ghrelin concentrations.
Clinical, humoral, and pathologic findings in adult alpacas with experimentally induced Corynebacterium pseudotuberculosis infection
Authors: Braga Walter U. , Chavera Alfonso E. , González Armando E.
Published: September 2006

Objective—To experimentally infect adult alpacas by ID inoculation of Corynebacterium pseudotuberculosis, follow the clinical and pathologic course of disease, and study the humoral response to infection.

Animals—13 adult alpacas.

Procedures—9 alpacas were inoculated with 1.1 X 106 CFUs of C pseudotuberculosis from llama (n = 4) or alpaca (5) origin, and 4 alpacas were sham inoculated as controls. Alpacas were clinically observed after inoculation and euthanatized on days 16, 58, 93, or 128 after inoculation; necropsy examination and histologic evaluation were performed. An indirect ELISA, which made use of the C pseudotuberculosis cell wall as the antigen, was used to measure antibody titers in serum samples.

Results—Alpacas had a persistent febrile response, a local severe inflammatory response, and leucocytosis (> 30 X 103 WBCs/μL). Internal abscesses that localized mainly in the renal lymph node were observed. Corynebacterium pseudotuberculosis was recovered from the inoculation site 1 week after inoculation and from internal abscesses at 58 days after inoculation. Initial lesions were typical pyogranulomas with central caseous necrosis, whereas later lesions consisted of connective tissue, mononuclear cells, abundant neutrophils, and liquefactive necrosis. Infected alpacas had detectable serum antibody titers starting on day 16 that persisted until day 93 after inoculation. Shaminoculated alpacas did not develop serum antibody titers, clinical signs of infection, or lesions.

Conclusions and Clinical Relevance—Alpacas inoculated with C pseudotuberculosis developed abscesses at the inoculation site and internally in the renal lymph nodes, without lung lesions. Corynebacterium pseudotuberculosis isolates from llama and alpaca origin were found to be pathogenically indistinct.
Isolation and characterization of a coronavirus from pigeons with pancreatitis
Authors: Qian Dong H. , Zhu Guo J. , Wu Li Z. , Hua Guo X.
Published: September 2006

Objective—To identify and partially characterize a coronaviruslike virus isolated from naturally infected pigeons.

Animals—50 specific pathogen-free (SPF) embryonated chicken eggs, 30 White Leghorn SPF chickens, and 12 clinically normal pigeons.

Procedures—Pancreatic tissue specimens from sick pigeons were inoculated into SPF embryonated chicken eggs for viral isolation and investigation of morphologic and hemagglutinating properties of the isolate, called PSH050513. Furthermore, virulence studies in SPF chickens and experimental pigeons were performed. The spike (S) glycoprotein gene of PSH050513 was further sequenced and analyzed.

Results—PSH050513 was isolated and identified from the experimentally infected pigeons by a routine method, which was in accordance with Koch's postulates. The complete S protein (1,167 amino acids) was compared with published S protein sequences of other avian and mammalian coronaviruses. A high degree of sequence identity (79.3% to 99.6%) was observed between the S protein sequence of PSH050513 and published sequences of avian infectious bronchitis virus (IBV); only limited identity (< 37.8%) was observed with turkey coronavirus and mammalian coronaviruses. Furthermore, when the virus was inoculated into SPF chickens, pancreatitis developed.

Conclusions and Clinical Relevance—PSH050513 has been tentatively identified as a novel member of group 3 coronaviruses that have close genetic relationships with IBV strains.
Prevalence and antimicrobial resistance patterns of Salmonella enterica in preweaned calves from dairies and calf ranches
Authors: Berge Anna Catharina B. , Moore Dale A. , Sischo William M.
Published: September 2006

Objective—To evaluate serovar and antimicrobial resistance patterns of Salmonella enterica isolated from preweaned calves and identify management risk factors associated with fecal shedding of S enterica.

Sample Population—Cohorts of 10 to 15 preweaned calves (1 to 84 days of age) on 26 dairies and 7 calf ranches and cross-sectional samples of preweaned calves on smaller farms.

Procedures—Calves were evaluated every 2 weeks during a 6-week period. Salmonella isolates obtained from rectal fecal swabs underwent antimicrobial susceptibility testing against 12 antimicrobials. Cluster analysis enabled description of antimicrobial susceptibility patterns. Calf, cohort, and farm risk factors associated with both the prevalence of S enterica and multiple-antimicrobial–resistant S enterica in preweaned calves were identified with repeated-measure logistic regression models.

Results—Salmonella enterica was detected on > 50% of farms and in 7.5% of 3,686 fecal samples. Many isolates (33%) were resistant to multiple antimicrobials. Shedding of Salmonella spp was negatively associated with increasing calf age, herds being closed to incoming cattle, and antimicrobial supplementation of milk replacer; prophylactic antimicrobial treatment in day-old calves increased shedding. No association between farm management and presence of multiple-antimicrobial–resistant S enterica or between calving management and presence of S enterica in calves ≤ 1 week old was detected.

Conclusions and Clinical Relevance—In preweaned calves, the most important factors associated with decreased likelihood of fecal shedding of S enterica were the use of antimicrobial-supplemented milk replacer and maintenance of a closed herd. Infection with multiple-antimicrobial–resistant S enterica was not associated with antimicrobial administration.
Proglycogen, macroglycogen, glucose, and glucose-6-phosphate concentrations in skeletal muscles of horses with polysaccharide storage myopathy performing light exercise
Authors: Bröjer Johan T. , Essén-Gustavsson Birgitta , Annandale Erin J. , Valberg Stephanie J.
Published: September 2006

Objective—To determine concentrations of proglycogen (PG), macroglycogen (MG), glucose, and glucose-6-phosphate (G-6-P) in skeletal muscle of horses with polysaccharide storage myopathy (PSSM) before and after performing light submaximal exercise.

Animals—6 horses with PSSM and 4 control horses.

Procedures—Horses with PSSM completed repeated intervals of 2 minutes of walking followed by 2 minutes of trotting on a treadmill until muscle cramping developed. Four untrained control horses performed a similar exercise test for up to 20 minutes. Serum creatine kinase (CK) activity was measured before and 4 hours after exercise. Concentrations of total glycogen (Gt), PG, MG, G-6-P, free glucose, and lactate were measured in biopsy specimens of gluteal muscle obtained before and after exercise.

Results—Mean serum CK activity was 26 times higher in PSSM horses than in control horses after exercise. Before exercise, muscle glycogen concentrations were 1.5, 2.2, and 1.7 times higher for PG, MG, and Gt, respectively, in PSSM horses, compared with concentrations in control horses. No significant changes in Gt, PG, MG, G-6-P, and lactate concentrations were detected after exercise. However, free glucose concentrations in skeletal muscle increased significantly in PSSM horses after exercise.

Conclusions and Clinical Relevance—Analysis of the results suggests that glucose uptake in skeletal muscle is augmented in horses with PSSM after light exercise. There is excessive storage of PG and MG in horses with PSSM, and high concentrations of the 2 glycogen fractions may affect functional interactions between glycogenolytic and glycogen synthetic enzymes and glycosomes.
Effects of platelet-derived growth factor-BB on the metabolic function and morphologic features of equine tendon in explant culture
Authors: Haupt Jennifer L. , Donnelly Brandon P. , Nixon Alan J.
Published: September 2006

Objective—To evaluate the effects of recombinant human platelet–derived growth factor-BB (rhPDGF-BB) on the metabolic function and morphologic features of equine superficial digital flexor tendon (SDFT) in explant culture.

Animals—6 euthanized horses (2 to 5 years old).

Methods—Forelimb SDFT explants were cultured for 6 days as untreated control specimens or treated with rhPDGF-BB (1, 10, 50, or 100 ng/mL of medium). Treatment effects on explant gene expression were evaluated via real-time PCR analysis of collagen type I, collagen type III, PDGF-A, and PDGF-B mRNA. Explants were assayed for total collagen, glycosaminoglycan, and DNA content; histologic changes were assessed via H&E staining and immunohistochemical localization of collagen types I and III.

Results—No morphologic or proliferative changes were detected in tendon explant sections. After high-dose rhPDGF-BB treatment, gene expression of collagen types I and III was increased and decreased, respectively. Expression of PDGF-A and PDGF-B mRNA was significantly increased at 24 hours, but later decreased to have few or negative autoinductive effects. Although PDGF gene expression waned after 48 hours of culture, collagen type I gene expression was significantly increased at 48 hours and reached peak value on day 6. Glycosaminoglycan and DNA content of explants were unchanged with rhPDGF-BB treatment.

Conclusions and Clinical Relevance—Results suggest that rhPDGF-BB use may be of benefit in the repair of equine tendon, particularly through induction of collagen type I mRNA. Positive autoinductive effects of PDGF-BB in equine SDFT explants were detected early following culture medium supplementation, but these diminished with time.
Morphologic and morphometric magnetic resonance imaging features of Doberman Pinschers with and without clinical signs of cervical spondylomyelopathy
Authors: da Costa Ronaldo C. , Parent Joane M. , Partlow Gary , Dobson Howard , Holmberg David L. , LaMarre Jonathan
Published: September 2006

Objective—To compare morphologic and morphometric features of the cervical vertebral column and spinal cord of Doberman Pinschers with and without clinical signs of cervical spondylomyelopathy (CSM; wobbler syndrome) detected via magnetic resonance imaging (MRI).

Animals—16 clinically normal and 16 CSM-affected Doberman Pinschers.

Procedures—For each dog, MRI of the cervical vertebral column (in neutral and traction positions) was performed. Morphologically, MRI abnormalities were classified according to a spinal cord compression scale. Foraminal stenosis and intervertebral disk degeneration and protrusion were also recorded. Morphometric measurements of the vertebral canal and spinal cord were obtained in sagittal and transverse MRI planes.

Results—4 of 16 clinically normal and 15 of 16 CSM-affected dogs had spinal cord compression. Twelve clinically normal and all CSM-affected dogs had disk degeneration. Foraminal stenosis was detected in 11 clinically normal and 14 CSM-affected dogs. Vertebral canal and spinal cord areas were consistently smaller in CSM-affected dogs, compared with clinically normal dogs. In neutral and traction positions, the intervertebral disks of CSM-affected dogs were wider than those of clinically normal dogs but the amount of disk distraction was similar between groups.

Conclusions and Clinical Relevance—The incidence of intervertebral disk degeneration and foraminal stenosis in clinically normal Doberman Pinschers was high; cervical spinal cord compression may be present without concurrent clinical signs. A combination of static factors (ie, a relatively stenotic vertebral canal and wider intervertebral disks) distinguished CSM-affected dogs from clinically normal dogs and appears to be a key feature in the pathogenesis of CSM.
Correlation of motor evoked potentials with magnetic resonance imaging and neurologic findings in Doberman Pinschers with and without signs of cervical spondylomyelopathy
Authors: da Costa Ronaldo C. , Poma Roberto , Parent Joane M. , Partlow Gary , Monteith Gabrielle
Published: September 2006

Objective—To establish the reference ranges for motor evoked potential (MEP) latency and amplitude in clinically normal Doberman Pinschers, compare the MEPs of Doberman Pinschers with and without clinical signs of cervical spondylomyelopathy (CSM; wobbler syndrome), and determine whether MEP data correlate with neurologic or magnetic resonance imaging (MRI) findings.

Animals—16 clinically normal and 16 CSM-affected Doberman Pinschers.

Procedures—Dogs were classified according to their neurologic deficits. After sedation with acepromazine and hydromorphone, transcranial magnetic MEPs were assessed in each dog; latencies and amplitudes were recorded from the extensor carpi radialis and cranial tibial muscles. Magnetic resonance imaging was performed to evaluate the presence and severity of spinal cord compression.

Results—Significant differences in cranial tibial muscle MEP latencies and amplitudes were detected between clinically normal and CSM-affected dogs. No differences in the extensor carpi radialis MEP were detected between groups. There was a significant correlation (r = 0.776) between the cranial tibial muscle MEP latencies and neurologic findings. Significant correlations were also found between MRI findings and the cranial tibial muscle MEP latencies (r = 0.757) and amplitudes (r = −0.453).

Conclusions and Clinical Relevance—Results provided a reference range for MEPs in clinically normal Doberman Pinschers and indicated that cranial tibial muscle MEP latencies correlated well with both MRI and neurologic findings. Because of the high correlation between cranial tibial muscle MEP data and neurologic and MRI findings, MEP assessment could be considered as a screening tool in the management of dogs with spinal cord disease.
Pharmacokinetics of pentoxifylline and its 5-hydroxyhexyl metabolite after oral and intravenous administration of pentoxifylline to healthy adult horses
Authors: Liska Dana A. , Akucewich Lisa H. , Marsella Rosanna , Maxwell Lara K. , Barbara Joanna E. , Cole Cynthia A.
Published: September 2006

Objective—To determine serum pharmacokinetics of pentoxifylline and its 5-hydroxyhexyl metabolite in horses after administration of a single IV dose and after single and multiple oral doses.

Animals—8 healthy adult horses.

Procedures—A crossover study design was used with a washout period of 6 days between treatments. Treatments were IV administration of a single dose of pentoxifylline (8.5 mg/kg) and oral administration of generic sustained-release pentoxifylline (10 mg/kg, q 12 h, for 8 days). Blood samples were collected 0, 1, 3, 6, 12, 20, 30, and 45 minutes and 1, 2, 4, 6, 8, and 12 hours after IV administration. For oral administration, blood samples were collected 0, 0.25, 0.5, 0.75, 1, 2, 4, 8, and 12 hours after the first dose and 0, 0.25, 0.5, 0.75, 1, 2, 4, 8, 12, and 24 hours after the last dose.

Results—Elimination of pentoxifylline was rapid after IV administration. After oral administration, pentoxifylline was rapidly absorbed and variably eliminated. Higher serum concentrations of pentoxifylline and apparent bioavailability were observed after oral administration of the first dose, compared with values after administration of the last dose on day 8 of treatment.

Conclusions and Clinical Relevance—In horses, oral administration of 10 mg of pentoxifylline/kg results in serum concentrations equivalent to those observed for therapeutic doses of pentoxifylline in humans. Twice daily administration appears to be appropriate. However, serum concentrations of pentoxifylline appear to decrease with repeated dosing; thus, practitioners may consider increasing the dosage if clinical response diminishes with repeated administration.
Immunohistochemical staining of urokinase plasminogen activator-like and urokinase plasminogen activator receptor-like proteins in the urinary tract of healthy dogs
Authors: Bailey Trina R. , Paulsen Daniel B. , Sehgal Inder , Hosgood Giselle
Published: September 2006

Objective—To determine distribution of urokinase plasminogen activator-like protein and urokinase plasminogen activator receptor-like protein in urinary tract tissues of healthy dogs.

Animals—11 healthy dogs.

Procedures—Necropsy specimens from kidney, ureter, bladder, urethra, prostate, and testis were obtained from 4 sexually intact female dogs, 5 sexually intact males, and 2 castrated males; dogs ranged in age from juvenile to adult. Urokinase plasminogen activator-like protein and urokinase plasminogen activator receptor-like protein in tissue lysates from kidney, prostate, and testis were identified by use of SDS-PAGE, western blot analysis, and immunoprecipitation. Urokinase plasminogen activator-like protein and urokinase plasminogen activator receptor-like protein in kidney, ureter, urinary bladder, urethra, prostate, and testis were identified by use of immunohistochemical staining of tissue sections.

Results—Urokinase plasminogen activator-like protein and urokinase plasminogen activator receptor-like protein in the molecular-weight range published for urokinase and urokinase receptor (53 and 33 kd for urokinase and 60 to 65 kd for urokinase receptor) were identified. Distribution of the proteins identified by use of immunohistochemical staining was comparable with published information for humans and mice for the urinary tract. Staining of these proteins was detected in more tissue types than reported in healthy humans.

Conclusions and Clinical Relevance—Urokinase plasminogen activator-like protein and urokinase plasminogen activator receptor-like protein were detected in the urinary tract of healthy dogs. This information is important for further evaluation of the functions of urokinase and urokinase receptor in the canine urinary tract and the pathophysiologic features of urinary tract disease.
Lifelong diet restriction and radiographic evidence of osteoarthritis of the hip joint in dogs
Authors: Smith Gail K. , Paster Erin R. , Powers Michelle Y. , Lawler Dennis F. , Biery Darryl N. , Shofer Frances S. , McKelvie Pamela J. , Kealy Richard D.
Published: September 2006

Objective—To evaluate the effects of diet restriction on development of radiographic evidence of hip joint osteoarthritis in dogs.

Design—Longitudinal cohort study.

Animals—48 Labrador Retrievers from 7 litters.

Procedures—Forty-eight 6-week-old puppies from 7 litters were paired with littermates by sex and weight, and each pairmate was randomly assigned to 1 of 2 groups of 24 dogs each. Starting at 8 weeks of age, 1 group was fed ad libitum (control fed) and the other was fed 25% less (restricted fed) of the same diet for life on a pairwise basis. The dogs' hip joints were radiographed in the standard ventrodorsal hip-extended view at multiple intervals prior to 1 year of age and at annual intervals thereafter on the basis of birth anniversary. A board-certified radiologist unaware of group assignment scored the radiographs for evidence of osteoarthritis.

Results—Prevalence of radiographic evidence of hip joint osteoarthritis in all dogs increased linearly throughout the study, from an overall prevalence of 15% at 2 years to 67% by 14 years. Restricted-fed dogs had lower prevalence and later onset of hip joint osteoarthritis. Median age at first identification of radiographic evidence of hip joint osteoarthritis was significantly lower in the control-fed group (6 years), compared with the restricted-fed group (12 years).

Conclusions and Clinical Relevance—Restricted feeding delayed or prevented development of radiographic signs of hip joint osteoarthritis in this cohort of Labrador Retrievers. Lifetime maintenance of 25% diet restriction delayed onset and reduced severity of hip joint osteoarthritis, thus favorably affecting both duration and quality of life. In addition, the data indicated that development of hip joint osteoarthritis was not bimodal in these dogs but occurred as a continuum throughout life.
Development of antimicrobial drug resistance in rectal Escherichia coli isolates from dogs hospitalized in an intensive care unit
Authors: Ogeer-Gyles Jennifer , Mathews Karol A. , Sears William , Prescott John F. , Weese J. S. , Boerlin Patrick
Published: September 2006

Objective—To determine whether duration of hospitalization in the intensive care unit (ICU) of a veterinary teaching hospital was associated with prevalence of antimicrobial resistance among rectal Escherichia coli isolates from dogs, whether antimicrobial treatment was associated with prevalence of antimicrobial resistance, and whether there were associations among antimicrobial drugs to which isolates were resistant.

Design—Prospective observational study.

Animals—116 dogs hospitalized in an ICU for ≥ 3 days.

Procedures—Rectal swab specimens were obtained every 3 days and submitted for bacterial culture for E coli. Isolates were tested for susceptibility to 12 antimicrobial agents by means of disk diffusion.

Results—For each additional day that a dog was hospitalized in the ICU, the odds of being colonized with an E coli isolate resistant to 1 or more of the 12 antimicrobials tested increased by a factor of 1.5, independent of antimicrobial treatment. Dogs that were treated with enrofloxacin were 25.6 times as likely to be colonized by a quinolone-resistant E coli strain as were dogs that did not receive any antimicrobials. Significant correlations were found for resistance to agents in the extended-spectrum cephalosporin group and the quinolone group.

Conclusions and Clinical Relevance—Results suggested that the proportion of rectal E coli isolates obtained from dogs housed for ≥ 3 days in a veterinary teaching hospital ICU that were resistant to antimicrobial agents increased as the duration of hospitalization in the ICU increased. Thus, ICU hospitalization time should be as short as possible to prevent development of antimicrobial resistance among rectal E coli isolates.
Forelimb amputation for treatment of a peripheral nerve sheath tumor in an African pygmy hedgehog
Authors: Martin Kacie K. , Johnston Matthew S.
Published: September 2006

Case Description—A 6-year-old female African pygmy hedgehog was evaluated because of a mass of unknown duration on the lateral aspect of the right shoulder region.

Clinical Findings—A fine-needle aspirate of the mass was collected for cytologic examination; findings were consistent with a spindle cell tumor. A CBC, plasma biochemical analyses, and whole-body radiography revealed no other abnormalities.

Treatment and Outcome—An initial surgery performed in an attempt to remove the mass with preservation of the limb failed in that tumor-free surgical margins were not obtained. Histologically, the mass was identified as a peripheral nerve sheath tumor (neurofibrosarcoma). A second surgery to amputate the forelimb was successful. After 1 year, there had been no further development of peripheral nerve sheath tumor at this or other sites.

Clinical Relevance—In African pygmy hedgehogs, potential differential diagnoses for a subcutaneous mass should include peripheral nerve sheath tumor. If necessary, forelimb amputation can be performed successfully in this species with procedures modified from those used in dogs. Information gathered during the treatment and recovery of the hedgehog of this report may assist practicing veterinarians in counseling owners of hedgehogs that are undergoing forelimb amputation with regard to the course of recovery that may be expected following this procedure.
Comparison of recoveries from anesthesia of horses placed on a rapidly inflating-deflating air pillow or the floor of a padded stall
Authors: Ray-Miller Wendy M. , Hodgson David S. , McMurphy Rose M. , Chapman Phillip L.
Published: September 2006

Objective—To compare recoveries from anesthesia of horses placed on a conventional padded stall floor or on a specially designed air pillow.

Design—Prospective study.

Animals—409 horses (> 1 year old) that were anesthetized for surgical procedures during a 37-month period.

Procedures—By random allocation, horses were allowed to recover from anesthesia in either a foammat–padded recovery stall or an identical recovery stall equipped with a rapidly inflating-deflating air pillow. All recoveries were videotaped for subsequent analysis by an independent evaluator. Times to first movement, first attempt to attain sternal recumbency, attainment of sternal recumbency, first attempt to stand, and successful standing were recorded. The numbers of attempts before achieving sternal recumbency and standing were counted, and scores for quality of standing and overall recovery were assigned. Recovery-related variables were compared between groups.

Results—Compared with horses allowed to recover in a conventional manner, horses that recovered from anesthesia on the air pillow had a significantly longer rest period before attempting to attain sternal recumbency and rise to standing. Once the pillow was deflated, horses were able to stand after significantly fewer attempts and the quality of their standing was significantly better. Between the 2 groups of horses, there was no significant difference in overall recovery quality scores. The air pillow and padded floor systems were equally safe.

Conclusions and Clinical Relevance—Results suggested that use of a rapidly inflating-deflating air pillow promotes a longer period of recumbency and a better quality of standing after anesthesia in horses.
Use of magnetic resonance imaging to diagnose distal sesamoid bone injury in a horse
Authors: Barber Matthew J. , Sampson Sarah N. , Schneider Robert K. , Baszler Timothy , Tucker Russell L.
Published: September 2006

Case Description—A 5-year-old Appaloosa mare was examined for severe left forelimb lameness of 4 months' duration.

Clinical Findings—Lameness was evident at the walk and trot and was exacerbated when the horse circled to the left. Signs of pain were elicited in response to hoof testers placed over the frog of the left front hoof, and a palmar digital nerve block eliminated the lameness. Radiographs revealed no abnormalities, but magnetic resonance imaging (MRI) revealed increased bone density in the medullary cavity of the distal sesamoid (navicular) bone in the proton density and T2-weighted images and a defect in the fibrocartilage and subchondral bone of the flexor cortex.

Treatment and Outcome—Because of the absence of improvement after 4 months and the poor prognosis for return to soundness, the mare was euthanatized. An adhesion between the deep digital flexor tendon and the flexor cortex defect on the navicular bone was grossly evident, and histologic evaluation revealed diffuse replacement of marrow trabecular bone with compact lamellar bone. Changes were consistent with blunt traumatic injury to the navicular bone that resulted in bone proliferation in the medullary cavity.

Clinical Relevance—Use of MRI enabled detection of changes that were not radiographically evident and enabled accurate diagnosis of the cause of lameness. Navicular bone injury may occur without fracture and should be considered as a differential diagnosis in horses with an acute onset of severe unilateral forelimb lameness originating from the heel portion of the foot.
Streptococcus equi meningoencephalomyelitis in a foal
Authors: Finno Carrie , Pusterla Nicola , Aleman Monica , Mohr F. Charles , Price Teena , George Jeanne , Holmberg Tara
Published: September 2006

Case Description—A 4-month-old American Paint Horse colt was evaluated because of acute onset of ataxia, left-sided head tilt, and fever and a recently noticed heart murmur. Upper respiratory tract infection caused by Streptococcus equi subsp equi had been diagnosed at 3 months of age.

Clinical Findings—Hematologic abnormalities included leukocytosis, mature neutrophilia, monocytosis, and mild anemia. Analysis of a CSF sample revealed high total protein concentration and total nucleated cell count; nucleated cells consisted mainly of degenerate neutrophils. Results of a real-time PCR assay were positive for S equi subsp equi, and a diagnosis of S equi subsp equi meningoencephalomyelitis was made.

Treatment and Outcome—Treatment included administration of potassium penicillin and fluids, but the foal developed uroperitoneum and was subsequently euthanized. Postmortem examination revealed meningoencephalomyelitis, and S equi subsp equi was cultured from a brain aspirate. Additional findings included suppurative cystitis with rupture and neutrophilic myocarditis.

Clinical Relevance—Findings suggest that S equi subsp equi meningoencephalomyelitis should be considered in the differential diagnosis for foals with neurologic signs that have a history of strangles or exposure to affected horses.
Use of transfixation pin casts to treat adult horses with comminuted phalangeal fractures: 20 cases (1993–2003)
Authors: Joyce JoLynn , Baxter Gary M. , Sarrafian Tiffany L. , Stashak Ted S. , Trotter Gayle , Frisbie Dave
Published: September 2006

Objective—To determine the clinical applications, short and long-term survival, and complications of using transfixation pin casts for treatment of comminuted phalangeal fractures in adult horses.

Design—Retrospective case series.

Animals—20 horses.

Procedures—Medical records were reviewed to obtain information regarding signalment, fracture location, treatment methods, complications, and short-term survival (discharge from hospital). Long-term follow-up information was obtained via contact with owners or trainers.

Results—12 fractures were in a hind limb, and 8 were in a forelimb. Fourteen fractures occurred in a middle phalanx, and 6 occurred in a proximal phalanx. Eleven fractures were treated with internal fixation combined with transfixation pin casts, and 9 fractures were treated with transfixation pin casts alone. Transfixation pin casts were maintained for a mean of 52 days (median, 49 days; range, 1 to 131 days). Fourteen (70%) horses were discharged from the hospital, whereas 6 (30%) were euthanized during the treatment period. Reasons for euthanasia included secondary fracture of the third metacarpal or metatarsal bone, avascularity of the distal aspect of the limb associated with an open fracture, and displacement of the fracture after transfixation pin cast removal. A significantly greater number of horses was discharged from the hospital when the transfixation pin cast was maintained for > 40 days, compared with those in which the transfixation pin cast was maintained for < 40 days.

Conclusions and Clinical Relevance—Results suggested that horses should be maintained in a transfixation pin cast for a minimum of 40 days, as this was associated with an increase in short-term survival without an increased risk of catastrophic failure.