bluuebunny/crossref_metadata_2025 huggingface dataset:
In vitro characterization of the inhibitory effects of ketoconazole on metabolic activities of cytochrome P-450 in canine hepatic microsomes
Authors: Kuroha Masanori , Kuze Yoji , Shimoda Minoru , Kokue Eiichi
Published: December 2005

Objective—To evaluate the inhibitory potency of ketoconazole (KTZ) on the metabolic activities of isozymes of cytochrome P-450 (CYP) in dogs.

Animals—4 healthy 1-year-old male Beagles.

Procedure—Hepatic microsomes were harvested from 4 dogs after euthanasia. To investigate the effects of KTZ on CYP metabolic activities, 7- ethoxyresorufin, tolbutamide, bufuralol, and midazolam hydrochloride were used as specific substrates for CYP1A1/2, CYP2C21, CYP2D15, and CYP3A12, respectively. The concentrations of metabolites formed by CYP were measured by high-performance liquid chromatography, except for the resorufin concentrations that were measured by a fluorometric method. The reaction velocity-substrate concentration data were analyzed to obtain kinetic variables, including maximum reaction velocity, Michaelis-Menten constant, and inhibitory constant (Ki).

Results—KTZ competitively inhibited 7-ethoxyresorufin O-deethylation and midazolam 4-hydroxylation; it noncompetitively inhibited tolbutamide methylhydroxylation. Bufuralol 1'-hydroxylation was inhibited slightly by KTZ. The mean Ki values of KTZ were 10.6 ± 6.0, 17.0 ± 2.5, and 0.180 ± 0.131 µMfor 7-ethoxyresorufin O-deethylation, tolbutamide methylhydroxylation, and midazolam 4-hydroxylation, respectively.

Conclusion and Clinical Relevance—In dogs, KTZ at a therapeutic dose may change the pharmacokinetics of CYP3A12 substrates as a result of inhibition of their biotransformation. Furthermore, no influence of KTZ on the pharmacokinetics of CYP1A1/2, CYP2C21, and CYP2D15 substrates are likely. In clinical practice, adverse drug effects may develop when KTZ is administered concomitantly with a drug that is primarily metabolized by CYP3A12. (Am J Vet Res2002;63:900–905)
Effects of cyclophotocoagulation with a neodymium:yttrium-aluminum-garnet laser on corneal sensitivity, intraocular pressure, aqueous tear production, and corneal nerve morphology in eyes of dogs
Authors: Weigt Anne Kelley , Herring Ian P. , Marfurt Carl F. , Pickett J. Phillip , Duncan Robert B. , Ward Daniel L.
Published: December 2005

Objective—To determine effects of cyclophotocoagulation via administration of 100 J with a neodymium: yttrium aluminum garnet (Nd:YAG) laser on corneal touch threshold (CTT), intraocular pressure (IOP), aqueous tear production, and corneal nerve morphology in eyes of dogs.

Animals—15 dogs.

Procedure—Noncontact Nd:YAG laser was transsclerally applied (10 applications; 25 W for 0.1 seconds for each application to each of 4 quadrants) to the ciliary body of the left eye of 15 dogs; the right eye was the control eye. Corneal integrity, CTT, tear production as measured by the Schirmer tear test (STT), and IOP were evaluated for 14 days following laser treatment. On day 14, dogs were euthanatized, eyes harvested, and corneas stained with gold chloride. Major nerve bundles were analyzed by use of a drawing tube attached to a light microscope, and maximum diameters were measured by use of image analysis software.

Results—All laser-treated eyes had significantly higher CTT values, compared with control eyes. Six of 15 laser-treated eyes developed ulcerative keratitis. On most days, IOP was significantly lower in laser-treated eyes in both morning and evening. Laser-treated eyes had a significant decrease of approximately 1 nerve bundle/corneal quadrant. Values for STT or nerve bundle diameters did not differ significantly.

Conclusion and Clinical Relevance—Administration of 100 J with a Nd:YAG laser effectively reduced IOP while increasing CTT and caused a significant decrease in number, but not diameter, of major corneal nerve bundles. Nerve damage and corneal hypoesthesia are etiologic factors in ulcerative keratitis following Nd:YAG cyclophotocoagulation. (Am J Vet Res2002;63:906–915)
Evaluation of plasma carboxy-terminal cross-linking telopeptide of type I collagen concentration in horses
Authors: Carstanjen Bianca , Hoyle Nicholas R. , Gabriel Annick , Hars Olaf , Sandersen Charlotte , Amory Hélène , Remy Benoit
Published: December 2005

Objective—To evaluate a human assay for quantification of carboxy-terminal cross-linking telopeptide of type I collagen (CTX-I), assess the influence of age on plasma CTX-I concentration, investigate the relationship between plasma CTX-I and serum osteocalcin concentrations, and determine whether concentrations of plasma CTX-I or serum osteocalcin fluctuate in circadian manner in horses.

Horses—75 clinically normal horses.

Procedure—Cross-reactivity between equine serum CTX-I and CTX-I antibodies in an automated electrochemiluminescent sandwich antibody assay (ECLIA) was evaluated via a specificity test (ie, dilution test) and recovery calculation. Serum osteocalcin concentration was measured with an equine-specific osteocalcin radioimmunoassay. To analyze diurnal variations in plasma CTX-I and serum osteocalcin concentrations, blood samples were obtained hourly during a 24-hour period.

Results—Results of the dilution test indicated good correlation (r> 0.99) between expected serum CTX-I concentrations and measured serum CTX-I concentrations. The calculated CTX-I recovery was 97.6% to 109.9%. Plasma CTX-I and serum osteocalcin concentrations were correlated. Plasma CTX-I concentration was inversely correlated with age of the horse. No significant circadian variations in plasma CTX-I and serum osteocalcin concentrations were detected.

Conclusions and Clinical Relevance—Results suggest that the fully automated CTX-I ECLIA can be used for evaluation of plasma and serum samples from horses and may be a useful tool to monitor bone metabolism changes. Horses in this study did not have notable diurnal fluctuations in serum osteocalcin and plasma CTX-I concentrations. (Am J Vet Res2004;65:104–109)
Effects of bovine lactoferrin hydrolysate on the in vitro antimicrobial susceptibility of Escherichia coli strains isolated from baby pigs
Authors: Chen Po-Wen , Ho Shu-Peng , Shyu Ching-Ling , Mao Frank C.
Published: December 2005

Objective—To determine the antibacterial activity of bovine lactoferrin hydrolysate (bLf-lysate) alone or in combination with other antimicrobials against antimicrobial-resistantEscherichia colistrains isolated from baby pigs.

Sample Population—3 clinical strains ofE coliwere isolated from baby pigs with severe diarrhea and designated as strains 9061, 9062, and 9065.

Procedure—The broth microdilution checkerboard and fractional inhibitory (or bactericidal) concentration index were used to evaluate the antibacterial effect elicited by bLf-lysate in combination with kanamycin, gentamicin, cephalothin, cefamandole, penicillin G, ampicillin, tetracycline, erythromycin, or rifampicin against the 3 strains ofE coli.

Results—The 3 strains ofE coliwere susceptible to gentamicin and rifampicin but highly resistant to most of the other antimicrobials tested, except for strain 9061 that was also susceptible to cephalothin but intermediately inhibited by kanamycin and cefamandole. Synergistic growth-inhibitory activity was observed between bLf-lysate and gentamicin against 1 strain ofE coli(strain 9062); synergistic bactericidal activity was found between bLf-lysate and rifampicin against all 3 strains ofE coli. Moreover, partial synergy was observed between bLf-lysate and kanamycin, gentamicin, cephalothin, or cefamandole against the strains ofE coli, but this partial synergistic activity was mostly seen against only 1 of the strains. Little interaction between bLf-lysate and tetracycline, ampicillin, penicillin G, or erythromycin was observed against the clinical strains ofE coli.

Conclusions and Clinical Relevance—A combination of bLf-lysate and certain antimicrobials may prove clinically effective against antimicrobial-resistant strains ofE coli. (Am J Vet Res2004;65:131–137)
Kinetic analysis of demethylation of 13C-aminopyrine in healthy dogs
Authors: Moeller E. Michael , Steiner Jörg M. , Williams David A. , Tetrick Mark , Burr John
Published: December 2005

Objective—To describe the kinetics of demethylation of13C-aminopyrine in healthy dogs for use in determining the most appropriate time for collection of blood samples for a13C-aminopyrine demethylation blood test for evaluation of hepatic function.

Animals—9 healthy dogs.

Procedures—A 2-mL baseline blood sample was collected into an evacuated heparinized tube, and13Caminopyrine was administered to each dog (2 mg/kg, IV). Additional 2-mL blood samples were collected 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 180, 240, 300, and 360 minutes after13C-aminopyrine administration. The CO2was extracted from blood samples by addition of a strong acid, and the percentage dose of13CO2(PCD) in the extracted gas was determined by fractional mass spectrometry.

Results—No dogs had gross evidence of adverse effects, and all had an increase in PCD after IV administration of13C-aminopyrine. The PCD had the least variability among 5 variables used to evaluate hepatic demethylating capacity. Peak PCD was detected at 30 minutes in 1 dog, 45 minutes in 5 dogs, 60 minutes in 2 dogs, and 75 minutes in 1 dog. The mean PCD for the 9 dogs peaked at 45 minutes after13C-aminopyrine administration.

Conclusions and Clinical Relevance—PCD appears to be the preferable variable for evaluation of hepatic demethylating capacity. Intravenous administration of13C-aminopyrine leads to a consistent increase in PCD. Mean PCD peaked 45 minutes after administration, suggesting that blood sample collection 45 minutes after13C-aminopyrine administration may be appropriate for use in estimating hepatic demethylating capacity. (Am J Vet Res2004;65:159–162)
Concentrations of gentamicin in serum and bronchial lavage fluid after once-daily aerosol administration to horses for seven days
Authors: McKenzie III Harold C. , Murray Michael J.
Published: December 2005

Objective—To assess gentamicin concentrations in serum and bronchial lavage fluid (BLF) of horses during a 24-hour period after once-daily aerosol administration of gentamicin (GAER) for 7 days and the pattern and degree of bronchial tree inflammation associated with repeated GAER.

Animals—13 healthy adult horses (9 geldings and 4 mares).

Procedure—The treatment group comprised 8 horses, and 5 horses were untreated control animals. Gentamicin (20 mL of gentamicin [50 mg/mL]) was administered via aerosol once daily for 7 days. Samples of serum and BLF were obtained from all horses before GAERand 0.5, 4, 8, and 24 hours after the final day of GAER. Gentamicin concentrations were determined for all samples from treated horses, and cytologic examinations were performed on all BLF samples.

Results—Peak median BLF gentamicin concentration detected at 0.5 hours was 2.50 µg/mL. Median serum gentamicin concentration was < 0.50 µg/mL at all time points. Significant differences were not observed in total nucleated cell counts or differential cell counts in BLF between groups at any time point. Neutrophil count in BLF for all horses was increased over baseline at 4 and 24 hours.

Conclusions and Clinical Relevance—We did not detect evidence of gentamicin accumulation or respiratory inflammation after once-daily GAERfor 7 days. This protocol appears unlikely to result in local or systemic toxicosis. Repeated daily GAERto horses appears to be a safe procedure and may have clinical use in the treatment of horses with bacterial infections of the airways. (Am J Vet Res2004;65:173–178)
Effects of atracurium on intraocular pressure, eye position, and blood pressure in eucapnic and hypocapnic isoflurane-anesthetized dogs
Authors: McMurphy Rose M. , Davidson Harriet J. , Hodgson David S.
Published: December 2005

Objective—To determine effects of atracurium on intraocular pressure (IOP), eye position, and arterial blood pressure in eucapnic and hypocapnic dogs anesthetized with isoflurane.

Animals—16 dogs.

Procedure—Ventilation during anesthesia was controlled to maintain PaCO2at 38 to 44 mm Hg in group-I dogs (n = 8) and 26 to 32 mm Hg in group-II dogs (8). Baseline measurements for IOP, systolic, diastolic, and mean arterial blood pressure, central venous pressure (CVP), and heart rate (HR) were recorded. Responses to peroneal nerve stimulation were monitored by use of a force-displacement transducer. Atracurium (0.2 mg/kg) was administered IV and measurements were repeated at 1, 2, 3, and 5 minutes and at 5-minute intervals thereafter for 60 minutes.

Results—Atracurium did not affect IOP, HR, or CVP. Group II had higher CVP than group I, but IOP was not different. There was no immediate effect of atracurium on arterial blood pressure. Arterial blood pressure increased gradually over time in both groups. Thirty seconds after administration of atracurium, the eye rotated from a ventromedial position to a central position and remained centrally positioned until 100% recovery of a train-of-four twitch response. The time to 100% recovery was 53.1 ± 5.3 minutes for group I and 46.3 ± 9.2 minutes for group II.

Conclusions and Clinical Relevance—Atracurium did not affect IOP or arterial blood pressure in isoflurane- anesthetized dogs. Hyperventilation did not affect IOP or the duration of effect of atracurium. (Am J Vet Res2004;65:179–182)
Evaluation of an electrolyte analyzer for measurement of ionized calcium and magnesium concentrations in blood, plasma, and serum of dogs
Authors: Unterer Stefan , Lutz Hans , Gerber Bernhard , Glaus Tony M. , Hässig Michael , Reusch Claudia E.
Published: December 2005

Objective—To evaluate an electrolyte analyzer for measurement of ionized calcium (Cai) and magnesium (Mgi) concentrations in blood, plasma, and serum; investigate the effect of various factors on measured values; and establish reference ranges for Caiand Mgiin dogs.

Animals—30 healthy adult dogs of various breeds.

Procedure—Precision in a measurement series, day-to-day precision, and linearity were used to evaluate the analyzer. The effects of exposure of serum samples to air, type of specimen (blood, plasma, or serum), and storage temperature on sample stability were assessed. Reference ranges were established with anaerobically handled serum.

Results—The coefficient of variation for precision in a measurement series was ≤ 1.5% for both electrolytes at various concentrations. The Caiand Mgiconcentrations were significantly lower in aerobically handled serum samples, compared with anaerobically handled samples. The Caiand Mgiconcentrations differed significantly among blood, plasma, and serum samples. In anaerobically handled serum, Caiwas stable for 24 hours at 22°C, 48 hours at 4°C, and 11 weeks at –20°C; Mgi was stable for 8 hours at 22°C, < 24 hours at 4°C, and < 1 week at –20°C. In anaerobically handled serum, reference ranges were 1.20 to 1.35 mmol/L for Caiand 0.42 to 0.58 mmol/L for Mgi.

Conclusions and Clinical Relevance—The electrolyte analyzer was suitable for determination of Caiand Mgiconcentrations in dogs. Accurate results were obtained in anaerobically handled serum samples analyzed within 8 hours and kept at 22°C. (Am J Vet Res2004;65:183–187)
Determination of passive mechanical properties of the superficial and deep digital flexor muscle-ligament-tendon complexes in the forelimbs of horses
Authors: Swanstrom Michael D. , Stover Susan M. , Hubbard Mont , Hawkins David A.
Published: December 2005

Objective—To determine the relative contributions of the muscles, tendons, and accessory ligaments to the passive force-length properties of the superficial (SDF) and deep digital flexor (DDF) myotendinous complexes.

Sample Population—8 cadaveric forelimbs from 6 adult Thoroughbreds.

Procedure—In vitro, limb configurations during slack position and myotendinous lengths during subsequent axial loading of forelimbs were recorded before and after transection of accessory ligaments. Expressions were derived to describe the forcelength behavior of each muscle, tendon, and accessory ligament-tendon unit; linear stiffness was computed for these components. The elastic modulus was established for the SDF and DDF tendons.

Results—Linear stiffness was 2.80 ± 0.38 kN/cm for the SDF muscle, 3.47 ± 0.66 kN/cm for the DDF muscle, 2.73 ± 0.18 kN/cm for the SDF tendon, 3.22 ± 0.20 kN/cm for the DDF tendon, 6.46 ± 0.85 kN/cm for the SDF accessory ligament, 1.93 ± 0.11 kN/cm for the SDF accessory ligament-tendon unit, and 2.47 ± 0.11 kN/cm for the DDF accessory ligament-tendon unit. The elastic modulus for the SDF and DDF tendons was 920 ± 77 and 843 ± 56 MPa, respectively.

Conclusions and Clinical Relevance—Both the muscle-tendon and ligament-tendon portions of SDF and DDF myotendinous complexes had important roles in supporting the forelimb of horses. Although muscle tension can be enhanced by elbow joint flexion and active contraction, the accessory ligaments transmitted more force to the distal tendons than did the muscles under the conditions tested. (Am J Vet Res2004;65:188–197)
Isolation, characterization, and expression of feline stromelysin-1 in naturally developing tumors in cats
Authors: Sorensen Kara C. , Kitchell Barbara E. , Siegel Arthur M. , Mardis Paul
Published: December 2005

Objective—To detect, isolate, and characterize feline stromelysin-1 (ie, matrix metalloproteinase [MMP]-3) in naturally developing tumors in cats.

Sample Population—31 tissue samples obtained from primary tumors and 6 samples of normal tissues from cats.

Procedure—Biopsy specimens were obtained from primary tumors. Primers were designed on the basis of known sequences. The sequence of stromelysin- 1 was cloned and analyzed. An additional primer set was used as a screening tool. Samples were assayed in duplicate or triplicate, when possible. Data obtained were analyzed for differences in expression of stromelysin-1 with regard to overall survival among cats of various sex, age, and disease status.

Results—A 1,181-bp cDNA nucleotide sequence was amplified. The open reading frame encoded 393 amino acids. This amino acid sequence shared 70% to 85% sequence homology with sequences of other species. In addition, samples were screened for stromelysin-1. Of the 31 tumor samples tested, 16 (51.6%) had positive results for expression of stromelysin-1. Total RNA expression was detected in a diverse group of tumor types. Prognostic factors associated with a shorter duration of survival included evidence of metastasis and metastasis associated with expression of stromelysin-1.

Conclusions and Clinical Relevance—Feline stromelysin-1 contains all the conserved regions typically found in members of the MMP family. Activity of stromelysin-1 has been implicated in a wide number of physiologic and pathologic processes. Identification of this gene may lead to the development of useful reagents to assist with diagnosis and management of neoplastic diseases in cats. (Am J Vet Res2004; 65:213–219)
Effects of infusion of adenosine triphosphatemagnesium chloride on cardiopulmonary and clinicopathologic variables, cytokine activity, and endothelin concentration in horses administered a low dose of endotoxin
Authors: Tetens Joanne , Moore Rustin M. , Hosgood Giselle L. , Eades Susan C. , Keowen Michael L. , Horohov David W.
Published: December 2005

Objective—To evaluate systemic effects of IV infusion of ATP-MgCl2subsequent to infusion of a low dose of endotoxin in horses.

Animals—12 adult horses.

Procedure—Horses were administered endotoxin (lipopolysaccharide [LPS]) or saline (0.9% NaCl) solution, IV, during a 30-minute period. Immediately thereafter, horses in each group were infused IV with ATP-MgCl2or saline solution. Two weeks later, horses were administered the opposite solution (LPS or saline solution), but it was followed by the same infusion as 2 weeks previously (ie, ATP-MgCl2or saline solution). Cardiopulmonary and clinicopathologic variables, cytokine activity, and endothelin (ET) concentrations were recorded.

Results—IV infusion of ATP-MgCl2after administration of a low dose of endotoxin failed to attenuate the cardiopulmonary, clinicopathologic, and cytokine alterations that develop secondary to endotoxin exposure. The combination of LPS and ATP-MgCl2potentiated pulmonary hypertension, leukopenia, and neutropenia when compared with the combination of LPS and saline solution. The combination of LPS and ATP-MgCl2resulted in thrombocytopenia. Endothelin concentration was increased in jugular venous and pulmonary arterial plasma in horses receiving LPS and ATP-MgCl2. Similar increases were not observed with LPS and saline solution.

Conclusions and Clinical Relevance—Administration of ATP-MgCl2did not protect horses from systemic effects of experimentally induced endotoxemia. Furthermore, the use of ATP-MgCl2during endotoxemia may worsen the cardiopulmonary and clinicopathologic status of affected horses. Because ATP and other adenine nucleotides are released from cells during shock, their potential role in the development of hemodynamic derangements, leukocyte adherence, and coagulopathies during endotoxemic episodes warrants further investigation. (Am J Vet Res2004;65: 225–237)
Blood pressure assessment in healthy cats and cats with hypertensive retinopathy
Authors: Sansom Jane , Rogers Katherine , Wood James L. N.
Published: December 2005

Objective—To determine whether there was an association between hypertensive retinopathy and high systolic, diastolic, and mean arterial blood pressures in cats.

Animals—181 cats.

Procedure—Systolic, diastolic, and mean arterial blood pressures were measured by use of a noninvasive oscillometric technique. The range of blood pressure measurements in healthy cats from various age groups was determined. Associations among systolic, diastolic, and mean arterial blood pressure; hypertensive retinopathy; hyperthyroidism; left ventricular cardiac hypertrophy; chronic renal failure; and serum biochemical abnormalities were determined.

Results—All blood pressure measurements increased with age in healthy cats. The frequency of hypertensive retinopathy also increased with age and with blood pressure, and hypertensive retinopathy was particularly found in cats with systolic blood pressures > 168 mm Hg. There was an increased risk for hypertensive retinopathy in cats that were female, > 10 years old, and neutered. The risk of chronic renal failure also increased as blood pressure, particularly systolic blood pressure, increased.

Conclusions and Clinical Relevance—Hypertensive retinopathy was common in cats ≥ 10 years of age and was associated with systolic blood pressures > 168 mm Hg when measured by the noninvasive oscillometric technique. (Am J Vet Res2004;65:245–252)
Effects of injection of botulinum toxin type B into the external anal sphincter on anal pressure of horses
Authors: Adam-Castrillo David , White II Nathaniel A , Donaldson Lydia L. , Furr Martin O.
Published: December 2005

Objective—To determine effects on anal pressure of
horses after local injection of the external anal sphincter
with Clostridium botulinum toxin type B.

Animals—11 healthy adult horses.

Procedure—Peak and resting anal sphincter pressures
were measured with a custom-made rectal
probe that was connected to a pressure transducer.
Pressures were measured before treatment and after
injection with botulinum toxin type B (BTB) or saline
(0.9% NaCl) solution. Dose titration with 500, 1,000,
1,500, and 2,500 U of BTB was completed. Physical
changes, behavior, and anal pressure were recorded
for each horse.

Results—Injection of 1,000 U of BTB caused a significant
reduction in peak anal pressure from days 2 to
84, compared with pressure in control horses.
Maximal effect of the toxin was observed within the
first 15 days after injection, followed by a slow return
to baseline during the 168-day period. Injection of
2,500 U of BTB in the anal sphincter in 1 horse resulted
in lethargy, generalized weakness, and dysphagia
for 14 days. Adverse clinical effects were not
observed in horses after injections with 500, 1,000, or
1,500 U of BTB.

Conclusions and Clinical Relevance—The effect of
focal intramuscular injection of BTB in horses is similar
to that reported for other species. However, horses
appear to be more sensitive to BTB, compared
with other species, and clinical signs of botulism may
develop at doses exceeding 1,500 U. Injections of
BTB in the external anal sphincter of mares may be
useful to reduce incisional dehiscence after repair of
perineal lacerations. ( Am J Vet Res 2004;65:26–30)
Effects of a mock ultrasonographic procedure on cortisol concentrations during low-dose dexamethasone suppression testing in clinically normal adult dogs
Authors: May Elizabeth R. , Frank Linda A. , Hnilica Keith A. , Lane India F.
Published: December 2005

Objective—To determine whether the stress of an ultrasonographic procedure would interfere with the suppressive effect of dexamethasone during a lowdose dexamethasone suppression test (LDDST) in healthy dogs.

Animals—6 clinically normal adult dogs.

Procedure—In phase 1, an LDDST was performed 5 times at weekly intervals in each dog. Serum samples were obtained 0, 2, 4, 6, and 8 hours after dexamethasone injection. A mock 20-minute abdominal ultrasonographic examination was performed on all dogs at each time point during the LDDST on weeks 2 through 5. In phase 2, serum cortisol concentrations were measured before and immediately after a 20-minute mock abdominal ultrasonographic examination, as described for phase 1.

Results—We did not detect significant differences after dexamethasone injection when comparing median cortisol concentrations for weeks 2 to 5 (mock ultrasonographic procedure) with median concentration for week 1 (no mock ultrasonographic procedure). For 5 of the 6 dogs, cortisol concentrations after dexamethasone injection decreased to < 35.9 nmol/L after each mock ultrasonographic procedure and remained low for the duration of the LDDST. In phase 2, all dogs had significant increases in cortisol concentrations immediately after the mock ultrasonographic procedure.

Conclusions and Clinical Relevance—A 20-minute mock abdominal ultrasonographic examination performed during LDDST did not alter results of the LDDST in most dogs. Cortisol concentrations measured immediately after a mock ultrasonographic examination were significantly increased. Ultrasonographic procedures should be performed a minimum of 2 hours before collection of samples that will be used to measure cortisol concentrations. (Am J Vet Res2004;65:267–270)
Urodynamic effects of a percutaneously controlled static hydraulic urethral sphincter in canine cadavers
Authors: Adin Christopher A. , Farese James P. , Cross Alan R. , Provitola Mary K. , Davidson Jeffrey S. , Jankunas Hope
Published: December 2005

Objective—To describe a percutaneously controlled static hydraulic urethral sphincter (SHUS) and evaluate urodynamic effects of the SHUS in canine cadavers.

Sample Population—Cadavers of 6 adult female dogs.

Procedure—Cadavers were obtained immediately after dogs were euthanatized. Baseline maximal urethral closure pressure (MUCP) and cystourethral leak point pressure (CLPP) were measured by use of a urethral pressure profilometer. An SHUS system was constructed by use of a silicone vascular occluder and subcutaneous infusion port. The SHUS system was then placed around the pelvic urethra in each cadaver. Measurements of MUCP and CLPP were repeated after varying occlusion of the SHUS (0%, 25%, and 50% occlusion). Baseline MUCP and CLPP values were compared with values obtained at 0%, 25%, and 50% occlusion of the SHUS by use of repeatedmeasures ANOVA.

Results—Mean ± SD MUCP for canine cadavers was 7 ± 1.3 cm H2O at baseline, which increased to 127 ± 53 cm H2O after 50% occlusion of the SHUS. Mean CLPP was 11 ± 8.6 cm H2O at baseline, which increased to 73 ± 38 cm H2O after 50% occlusion of the SHUS. Mean MUCP and CLPP were significantly associated with the amount of occlusion.

Conclusions and Clinical Relevance—The SHUS had positive effects on MUCP and CLPP in canine cadavers. Therefore, additional evaluation of the SHUS in live dogs is warranted. (Am J Vet Res2004; 65:283–288)
Evaluation of transmission of swine influenza type A subtype H1N2 virus in seropositive pigs
Authors: Choi Young K , Goyal Sagar M , Joo Han S.
Published: December 2005

Objective—To examine clinical signs, virus infection
and shedding, and transmission of swine influenza
virus (SIV) subtype H1N2 among seropositive pigs.

Animals—Eighteen 3-week-old pigs with maternal
antibodies against SIV subtypes H1N1, H3N2, and
H1N2.

Procedure—Ten pigs (principal) were inoculated
intranasally with subtype H1N2 and 2 groups of contact
pigs (n = 4) each were mixed with principal pigs
on day 7 (group 1) or 28 (group 2). Two principal pigs
each were necropsied on days 4, 14, 21, 28, and 42
days after inoculation. Four pigs in each contact group
were necropsied 35 and 14 days after contact. Virus
excretion was evaluated after inoculation or contact.
Lung lesions and the presence of SIV in various tissues
were examined.

Results—Mild coughing and increased rectal temperature
were observed in principal pigs but not in contact
pigs. Nasal virus shedding was detected in all
principal pigs from day 2 for 3 to 5 days, in group 1
pigs from day 2 for 4 to 9 days after contact, and in
group 2 pigs from day 4 for 2 to 6 days after contact.
Trachea, lung, and lymph node specimens from
infected pigs contained virus. Antibody titers against
all 3 subtypes in all pigs gradually decreased.

Conclusions and Clinical Relevance—Protection
from viral infection and shedding was not observed in
pigs with maternal antibodies, but clinical disease did
not develop. Vaccination programs and good management
practices should be considered for control of
SIV subtype H1N2 infection on swine farms. ( Am J Vet Res 2004;65:303–306)
Evaluation of the six-minute walk test in dogs
Authors: Boddy Kirstin N. , Roche Brian M. , Schwartz Denise S. , Nakayama Tomohiro , Hamlin Robert L.
Published: December 2005

Objective—To determine the feasibility for use of a 6- minute walk test (6-MWT) in dogs with congestive heart failure (CHF) and document that the distance walked in 6 minutes decreases when a dog has CHF.

Animals—16 young mature male hound-crossbred dogs weighing between 25 and 37 kg.

Procedure—An unobstructed path (22.73 m) was measured in a hallway. Each dog was walked on a leash for 6 minutes; each dog was allowed to set its own pace. At the end of 6 minutes (as measured by use of a stopwatch), the total distance walked was measured. Heart rate (HR) obtained by auscultation and mean systemic arterial pressure (MAP) obtained by oscillometry were recorded before and after the 6- MWT. Heart failure was induced by use of rapid ventricular pacing. Mean of the distance walked, HR, and MAP before and after the 6-MWT were compared between the control period and after dogs developed induced CHF.

Results—Dogs with CHF had a significant increase in resting HR, significant decrease in MAP, and a significant decrease in the distance walked in 6 minutes. The MAP increased slightly after exercise during the control period but decreased slightly after exercise during the CHF period. Fractional shortening decreased significantly when dogs had CHF.

Conclusions and Clinical Relevance—Analysis of these results indicated that the distance walked in 6 minutes decreased significantly when a dog had CHF. The 6-MWT requires little time, space, or equipment and may replace the treadmill exercise test. (Am J Vet Res2004;65:311–313)
Development of a reverse transcriptasepolymerase chain reaction assay to detect feline herpesvirus-1 latency-associated transcripts in the trigeminal ganglia and corneas of cats that did not have clinical signs of ocular disease
Authors: Townsend Wendy M. , Stiles Jean , Guptill-Yoran Lynn , Krohne Sheryl G.
Published: December 2005

Objective—To develop a reverse transcriptase-polymerase chain reaction (RT-PCR) assay to detect feline herpesvirus-1 (FHV-1) latency-associated transcripts (LATs) in the corneas and trigeminal ganglia of cats that did not have clinical signs of ocular disease.

Sample Population—Corneas and trigeminal ganglia obtained from 21 cats necropsied at the Indiana Animal Disease Diagnostic Laboratory and 25 cats euthanatized at a humane shelter; none of the cats had a recent history of respiratory tract or ocular disease, and all had normal results for ophthalmic examinations.

Procedure—Both corneas and both trigeminal ganglia were harvested from each cat. An initial PCR assay detected FHV-1 DNA in the corneas and trigeminal ganglia. The RNA was then isolated from samples positive for FHV-1 DNA, and an RT-PCR assay was used to detect LATs.

Results—FHV-1 DNA was detected in 45 of 92 (48.9%) corneas and 38 of 92 (41.3%) trigeminal ganglia. In many samples, the RNA had degraded and RTPCR assay was not possible. Of the samples subjected to RT-PCR assay, none of the 39 corneas but 4 of 16 trigeminal ganglia had positive results when tested for LATs.

Conclusions and Clinical Relevance—Analysis of the results indicated that a high percentage of cats that did not have clinical signs of ocular disease had detectable FHV-1 DNA in their corneas and trigeminal ganglia. This study documents that the RT-PCR assay can successfully identify LATs and may serve as a tool to better understand the biologic characteristics of FHV-1 and its relationship to clinical disease. (Am J Vet Res2004;65:314–319)
Use of multifrequency bioelectrical impedance analysis for estimation of total body water and extracellular and intracellular fluid volumes in horses
Authors: Fielding C. Langdon , Magdesian K. Gary , Elliott Denise A. , Cowgill Larry D. , Carlson Gary P.
Published: December 2005

Objective—To evaluate the use of multifrequency bioelectrical impedance analysis (MF-BIA) for estimating total body water (TBW), extracellular fluid volume (ECFV), and intracellular fluid volume (ICFV) in horses.

Animals—9 healthy mares.

Procedure—TBW and ECFV were measured by use of deuterium oxide and sodium bromide dilution techniques, respectively. Intracellular fluid volume was calculated as the difference between TBW and ECFV. Concurrently, MF-BIA recordings were obtained by use of 4 anatomic electrode positions and 3 measurements of length. Models for MF-BIA data were created for all combinations of length and anatomic electrode position. Models were evaluated to determine the position-length configuration that provided the most consistent estimates of TBW, ECFV, and ICFV, compared with values determined by use of the dilution techniques.

Results—Positioning electrodes over the ipsilateral carpus and tarsus and use of height at the tuber sacrale for length provided the closest estimate between values for TBW, ECFV, and ICFV predicted by use of MF-BIA and measured values obtained by dilutional techniques. This model had the narrowest 95% limits of agreement.

Conclusions and Clinical Relevance—MF-BIA techniques have been used to predict changes in TBW, ECFV, and ICFV in healthy and diseased humans. Results reported in this study provide an equine-specific model to serve as the basis for further evaluation of MF-BIA in horses with altered fluid states. The MF-BIA techniques have a number of potential applications for use in horses, including evaluation of exercise physiology, pharmacologic studies, and critical-care management. (Am J Vet Res2004;65:320–326)
Inheritance of cricopharyngeal dysfunction in Golden Retrievers
Authors: Davidson Autumn P. , Pollard Rachel E. , Bannasch Danika L. , Marks Stanley L. , Hornof William J. , Famula Thomas R.
Published: December 2005

Objective—To characterize a genetic component to
cricopharyngeal dysfunction (CD) in Golden Retrievers.

Animals—117 dogs.

Procedure—The CD phenotype was determined by
videofluoroscopy, and dogs were classified as affected
if the upper esophageal sphincter (UES) did not open,
if there were morphologic abnormalities of the UES, or
if opening of the UES was delayed for ≥ 6 videofluoroscopic
frames (0.2 seconds) after closure of the
epiglottis. All survey radiographic and videofluoroscopic
studies were reviewed by the same radiologist.

Results—Of the 117 dogs (47 males and 70 females)
with a CD phenotype determined via videofluoroscopy,
21 dogs (18.0%) had abnormalities of the
UES (affected). Of these 21 dogs, 9 were males
(19.1% of all males) and 12 were females (17.1% of all
females). The heritability of CD in a threshold model
was estimated as 0.61, which established that CD
could be passed from parent to offspring. Results of
complex segregation analysis suggested that a single
recessive allele of large effect contributed to the
expression of this disease in Golden Retrievers.

Conclusions and Clinical Relevance—The determination
that CD is inherited in Golden Retrievers is an
important step in providing information for veterinarians
attending dogs with this disorder. Breeders also
require this information to make informed breeding
decisions. ( Am J Vet Res 2004;65:344–349)
Pharmacokinetics of enrofloxacin in neonatal kittens
Authors: Seguin M. Alexis , Papich Mark G. , Sigle Kelly J. , Gibson Nicole M. , Levy Julie K.
Published: December 2005

Objective—To determine the pharmacokinetics of enrofloxacin in neonatal kittens and compare the pharmacokinetics of enrofloxacin in young and adult cats.

Animals—7 adult cats and 111 kittens (2 to 8 weeks old).

Procedure—A single dose of 5 mg of enrofloxacin/kg was administered to adults (IV) and kittens (IV, SC, or PO). Plasma concentrations of enrofloxacin and its active metabolite, ciprofloxacin, were determined.

Results—The half-life of enrofloxacin administered IV in 2-, 6-, and 8-week-old kittens was significantly shorter and its elimination rate significantly greater than that detected in adults. The apparent volumes of distribution were lower at 2 to 4 weeks and greater at 6 to 8 weeks. This resulted in lower peak plasma concentration (Cmax) at 6 to 8 weeks; however, initial plasma concentration was within the therapeutic range after IV administration at all ages. Compared with IV administration, SC injection of enrofloxacin in 2-weekold kittens resulted in similar Cmax, half-life, clearance, and area under the curve values. Enrofloxacin administered via SC injection was well absorbed in 6- and 8- week-old kittens, but greater clearance and apparent volume of distribution resulted in lower plasma concentrations. Oral administration of enrofloxacin resulted in poor bioavailability.

Conclusions and Clinical Relevance—In neonatal kittens, IV and SC administration of enrofloxacin provided an effective route of administration. Oral administration of enrofloxacin in kittens did not result in therapeutic drug concentrations. Doses may need to be increased to achieve therapeutic drug concentrations in 6- to 8-week-old kittens. (Am J Vet Res2004;65:350–356)
Cardiovascular effects of insufflation of the abdomen with carbon dioxide in standing horses sedated with detomidine
Authors: Cruz Antonio M. , Kerr Carolyn L. , Bouré Ludovic P. , Sears William C.
Published: December 2005

Objective—To determine the cardiovascular effects of 60 minutes of abdominal insufflation with CO2to an intra-abdominal pressure of 15 mm Hg in standing horses receiving a constant rate infusion of detomidine.

Animals—5 horses.

Procedure—Horses were randomly allocated into treatment or control groups. A washout period of a minimum of 7 days separated the 2 experimental periods of the crossover study. Catheters were placed into the right atrium, pulmonary artery, jugular vein, and right transverse facial artery after lidocaine infiltration. All horses were sedated with detomidine (8.54 µg/kg/h, IV). Horses in the treatment group received abdominal insufflation with CO2via a laparoscopic cannula to a final and constant intraabdominal pressure of 15 mm Hg for 60 minutes. Systemic arterial pressure, right atrial pressure, heart rate, cardiac output, core body temperature, and the pH and gas tensions of arterial and mixed venous blood were obtained. Cardiac index and systemic vascular resistance were calculated. Data were collected in 3 stages: preinsufflation (–10 and –5 minutes), insufflation (0, 15, 30, 45, and 60 minutes), and postinsufflation (70 and 80 minutes). The quality of sedation and level of analgesia were determined.

Results—The PaO2of horses in the treatment group was significantly higher after 60 minutes of pneumoperitoneum than in the control group. Core body temperature decreased significantly from baseline in both groups.

Conclusions and Clinical Relevance—A 60-minute period of abdominal insufflation to an intra-abdominal pressure of 15 mm Hg did not induce significant cardiovascular abnormalities in healthy horses. (Am J Vet Res2004;65:357–362)
Effects of a single intranasal dose of modified-live bovine respiratory syncytial virus vaccine on resistance to subsequent viral challenge in calves
Authors: Woolums Amelia R. , Brown Corrie C. , Brown Jr James C. , Cole Dana J. , Scott Melissa A. , Williams Shamita M. , Miao Congrong
Published: December 2005

Objective—To determine whether a single intranasal dose of modified-live bovine respiratory syncytial virus (BRSV) vaccine protects calves from BRSV challenge and characterize cell-mediated immune response in calves following BRSV challenge.

Animals—13 conventionally reared 4- to 6-week-old Holstein calves.

Procedure—Calves received intranasal vaccination with modified live BRSV vaccine (VC-group calves; n = 4) or mock vaccine (MC-group calves; 6) 1 month before BRSV challenge; unvaccinated control-group calves (n = 3) underwent mock challenge. Serum virus neutralizing (VN) antibodies were measured on days –30, -14, 0, and 7 relative to BRSV challenge; nasal swab specimens were collected for virus isolation on days 0 to 7. At necropsy examination on day 7, tissue specimens were collected for measurement of BRSV-specific interferon gamma (IFN-γ) production. Tissue distribution of CD3+ T and BLA.36+ B cells was evaluated by use of immunohistochemistry.

Results—The MC-group calves had significantly higher rectal temperatures, respiratory rates, and clinical scores on days 5 to 7 after BRSV challenge than VCgroup calves. No difference was seen between distributions of BRSV in lung tissue of VC- and MC-group calves. Production of BRSV-specific IFN-γ was increased in tissue specimens from VC-group calves, compared with MC- and control-group calves. Virusspecific IFN-γ production was highest in the mediastinal lymph node of VC-group calves. Increased numbers of T cells were found in expanded bronchialassociated lymphoid tissue and airway epithelium of VC-group calves.

Conclusions and Clinical Relevance—An intranasal dose of modified-live BRSV vaccine can protect calves against virulent BRSV challenge 1 month later. (Am J Vet Res2004;65:363–372)
Expression of matrix metalloproteinases in feline vaccine site-associated sarcomas
Authors: Sorensen Kara C. , Kitchell Barbara E. , Schaeffer David J. , Mardis Paul E.
Published: December 2005

Objective—To screen for expression of 9 predominant members of the matrix metalloproteinase (MMP) family, including membrane-type matrix metalloproteinases (MT-MMPs) and tissue inhibitors of metalloproteinases (TIMPs), in primary tumor tissue biopsy specimens of vaccine site-associated sarcomas (VSS) in cats and compare expression profiles of VSS with expression profiles of non-VSS and carcinomas.

Sample Population—31 primary tumor tissue biopsy specimens and 6 nontumor (normal) tissue biopsy specimens.

Procedure—Tissue specimens were obtained from primary tumor biopsy specimens of cats. Primers for reverse transcriptase-polymerase chain reaction assay were designed on the basis of known sequences. Data were analyzed for patterns of expression of MMPs, MT-MMPs, and TIMPs. Differences in expression patterns were evaluated among cats of differing genders, ages, metastasis status, and overall survival durations, and between cats with VSS and cats with non-VSS tumor types.

Results—A total of 31 primary tumor tissue biopsy specimens and 6 nontumor (normal) tissue biopsy specimens were screened for the presence of 6 MMPs and 3 TIMPs. Matrix metalloproteinase and TIMP expression was found in non-VSS, carcinomas, and VSS. No significant differences were found in patterns of expression among tumor types. Metastasis was found to be the only predictive factor for overall survival duration. A significant correlation was found between MMP2 and MT-MMP16 expression and overall duration of survival.

Conclusions and Clinical Relevance—The identification of MMPs in feline VSS supports an underlying inflammatory pathogenesis for this tumor. Expression of MMP2 and MT-MMP16 were correlated with survival time in our study. (Am J Vet Res2004; 65:373–379)
Effect of various distal ring-block configurations on the biomechanical properties of circular external skeletal fixators for use in dogs and cats
Authors: Cross Alan R. , Lewis Daniel D. , Rigaud Steve , Rapoff Andrew J.
Published: December 2005

Objective—To evaluate mediolateral, axial, torsional, and craniocaudal bending behavior of 6 distal ring-block configurations commonly used to stabilize short juxta-articular bone segments in small animals.

Sample Population—8 circular external skeletal fixator constructs of each of 6 distal ring-block configurations. The distal ring-block configurations were composed of combinations of complete rings, incomplete rings, and drop wires.

Procedure—Constructs were nondestructively loaded in axial compression, craniocaudal bending, mediolateral bending, and torsional loading by use of a materials testing machine. Gap stiffness was determined by use of the resultant load displacement curve.

Results—Circular external skeletal fixator configurations and constructs significantly affected gap stiffness in all testing modes. Within each loading mode, gap stiffness was significantly different among most configurations. In general, complete ring configurations were significantly stiffer than similar incomplete ring configurations, and addition of a drop wire to a configuration significantly increased stiffness of that configuration.

Conclusions and Clinical Relevance—When regional anatomic structures permit, the use of complete ring configurations is preferred over incomplete ring configurations. When incomplete ring configurations are used, the addition of a drop wire is recommended. (Am J Vet Res2004;65:393–398)
In vitro efficacy of ganciclovir, cidofovir, penciclovir, foscarnet, idoxuridine, and acyclovir against feline herpesvirus type-1
Authors: Maggs David J. , Clarke Heather E.
Published: December 2005

Objective—To establish the in vitro efficacy of 4 novel drugs (ie, ganciclovir, cidofovir, penciclovir, and foscarnet) against feline herpesvirus type-1 (FHV-1) and compare their antiviral efficacy with that of acyclovir and idoxuridine.

Sample Population—Cultured Crandell-Reese feline kidney (CRFK) cells and FHV-1 strain 727.

Procedure—For each drug, antiviral effect was estimated by use of conventional plaque-reduction assays, and inhibitory concentration 50 (IC50; drug concentration at which plaque numbers were reduced by 50% relative to the number of plaques for nontreated control wells) was calculated. To determine whether observed antiviral effects were related to alterations in the number or viability of CRFK cells, cytotoxicity assays were performed at 1, 2, and 10 times the median IC50for each antiviral drug.

Results—Median IC50for each drug was as follows: ganciclovir, 5.2µM; cidofovir, 11.0µM; penciclovir, 13.9µM; foscarnet, 232.9µM; idoxuridine, 4.3µM; and acyclovir, 57.9µM. Obvious changes in morphologic characteristics, confluence, or viability of CRFK cells were not observed at concentrations up to and including 2 times the IC50for each drug.

Conclusions and Clinical Relevance—In vitro efficacy of idoxuridine and ganciclovir against FHV-1 was approximately equivalent and about twice that of cidofovir and penciclovir. Foscarnet appeared to be comparatively ineffective. Given the reasonable clinical efficacy of idoxuridine in cats infected with FHV-1, clinical trials of ganciclovir, cidofovir, and penciclovir or their prodrug forms appear to be warranted. (Am J Vet Res2004;65:399–403)