bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of sevoflurane on hemodynamic and cardiac energetic parameters in ferrets
Authors: MacPhail Catriona M. , Monnet Eric , Gaynor James S. , Perini Alberto
Published: December 2005

Objective—To determine the effect of sevoflurane on cardiac energetic and hemodynamic parameters in ferrets.

Animals—7 healthy domesticated ferrets.

Procedure—Sevoflurane was used as the sole anesthetic agent for general anesthesia in ferrets. Standard midline laparotomy and median sternotomy were performed to permit instrumentation. Myocardial blood flow was determined by use of colored microsphere technology. Measurements and blood samples were obtained at 1.25%, 2.5%, and 3.75% expired concentration of sevoflurane.

Results—A dose-dependent decrease in arterial blood pressure, left ventricular pressure, systemic vascular resistance, aortic flow, and dp/dt (an index of contractility) was detected as expired concentration of sevoflurane increased. Heart rate, central venous pressure, coronary vascular resistance, myocardial oxygen extraction ratio, and(the time constant of relaxation) were unchanged. Cardiac external work decreased, as did myocardial oxygen consumption, causing increased cardiac efficiency at higher concentrations of sevoflurane.

Conclusions and Clinical Relevance—Sevoflurane caused minimal and predictable cardiovascular effects in ferrets without increasing myocardial metabolic demands. Data obtained from this study have not been previously reported for a species that is being commonly used in cardiovascular research. These findings also support use of sevoflurane as a safe inhalant anesthetic in ferrets for clinical and research settings. (Am J Vet Res2004:65:653–658)
Effects of feeding large amounts of grain on colonic contents and feces in horses
Authors: Lopes Marco A. F. , White II Nathaniel A. , Crisman Mark V. , Ward Daniel L.
Published: December 2005

Objective—To assess changes in systemic hydration, concentrations of plasma electrolytes, hydration and physical properties of colonic contents and feces, and gastrointestinal transit in horses with access to large amounts of grain.

Animals—6 horses with right dorsal colon (RDC) fistulas.

Procedure—In a crossover design, horses were alternately fed 1 of 3 diets: orchard grass hay ad libitum after being adapted to this diet for at least 5 days, orchard grass hay ad libitum and 4.55 kg of grain offered every 12 hours after being adapted to orchard grass hay ad libitum for at least 5 days, or orchard grass hay ad libitum and 4.55 kg of grain offered every 12 hours after being adapted to this diet for at least 5 days. Physical examinations were performed and samples of blood, colonic contents, and feces were collected every 6 hours during a 48-hour observation period.

Results—Grain ingestion had several effects, including changes in the concentrations of electrolytes in plasma; RDC contents became more homogenous, dehydrated, foamy, and less dense; RDC contents flowed spontaneously when the cannula was opened; RDC contents expanded when heated in an oven; and feces became fetid and less formed. Horses did not have any clinical signs of colic, endotoxemia, or laminitis.

Conclusions and Clinical Relevance—Changes observed in the colonic contents and feces may be explained by the large amounts of hydrolyzable carbohydrates provided by grain. Access to large amounts of grain may increase the risk of tympany and displacement of the large intestine. (Am J Vet Res2004;65:687–694)
Immunohistochemical identification and fiber type specific localization of protein kinase C isoforms in equine skeletal muscle
Authors: van Ginneken Mireille M.E. , Keizer Hans A. , Wijnberg Inge D. , van Dam Klien G. , Schaart Gert , de Graaf-Roelfsema Ellen , van der Kolk Johannes H. , van Breda Eric
Published: December 2005

Objective—To investigate whether protein kinase C (PKC) isoforms are expressed in equine skeletal muscle and determine their distribution in various types of fibers by use of immunofluorescence microscopy.

Animals—5 healthy adult Dutch Warmblood horses.

Procedure—In each horse, 2 biopsy specimens were obtained from the vastus lateralis muscle. Cryosections of equine muscle were stained with PKC isoform (α, β1, β2, δ, ξ, or ζ)-specific polyclonal antibodies and examined by use of a fluorescence microscope. Homogenized muscle samples were evaluated via western blot analysis.

Results—The PKC α, β1, β2, δ, ξ, and ζ isoforms were localized within the fibers of equine skeletal muscle. In addition, PKC α and β2 were detected near or in the plasma membrane of muscle cells. For some PKC isoforms, distribution was specific for fiber type. Staining of cell membranes for PKC α was observed predominantly in fibers that reacted positively with myosin heavy chain (MHC)-IIa; PKC δ and ξ staining were more pronounced in MHC-I-positive fibers. In contrast, MHC-I negative fibers contained more PKC ζ than MHC-I-positive fibers. Distribution of PKC β1 was equal among the different fiber types.

Conclusions and Clinical Relevance—Results indicated that PKC isoforms are expressed in equine skeletal muscle in a fiber type-specific manner. Therefore, the involvement of PKC isoforms in signal transduction in equine skeletal muscle might be dependent on fiber type. (Am J Vet Res2004; 65:69–73)
Effects of enteral and intravenous fluid therapy, magnesium sulfate, and sodium sulfate on colonic contents and feces in horses
Authors: Lopes Marco A. F. , White II Nathaniel A. , Donaldson Lydia , Crisman Mark V. , Ward Daniel L.
Published: December 2005

Objective—To assess changes in systemic hydration, concentrations of electrolytes in plasma, hydration of colonic contents and feces, and gastrointestinal transit in horses treated with IV fluid therapy or enteral administration of magnesium sulfate (MgSO4), sodium sulfate (NaSO4), water, or a balanced electrolyte solution.

Animals—7 horses with fistulas in the right dorsal colon (RDC).

Procedure—In a crossover design, horses alternately received 1 of 6 treatments: no treatment (control); IV fluid therapy with lactated Ringer's solution; or enteral administration of MgSO4, Na2SO4, water, or a balanced electrolyte solution via nasogastric intubation. Physical examinations were performed and samples of blood, RDC contents, and feces were collected every 6 hours during the 48 hour-observation period. Horses were muzzled for the initial 24 hours but had access to water ad libitum. Horses had access to hay, salt, and water ad libitum for the last 24 hours.

Results—Enteral administration of a balanced electrolyte solution and Na2SO4were the best treatments for promoting hydration of RDC contents, followed by water. Sodium sulfate was the best treatment for promoting fecal hydration, followed by MgSO4and the balanced electrolyte solution. Sodium sulfate caused hypocalcemia and hypernatremia, and water caused hyponatremia.

Conclusions and Clinical Relevance—Enteral administration of a balanced electrolyte solution promoted hydration of RDC contents and may be useful in horses with large colon impactions. Enteral administration of either Na2SO4or water may promote hydration of RDC contents but can cause severe electrolyte imbalances. (Am J Vet Res2004;65:695–704)
Effect of oral administration of dantrolene sodium on serum creatine kinase activity after exercise in horses with recurrent exertional rhabdomyolysis
Authors: McKenzie Erica C. , Valberg Stephanie J. , Godden Sandra M. , Finno Carrie J. , Murphy Michael J.
Published: December 2005

Objective—To determine the effect of oral administration of dantrolene sodium on serum creatine kinase (CK) activity after exercise in horses with recurrent exertional rhabdomyolysis (RER).

Animals—2 healthy horses and 5 Thoroughbreds with RER.

Procedure—3 horses received 2 doses of dantrolene (4, 6, or 8 mg/kg, PO, with and without withdrawal of food) 2 days apart; 90 minutes after dosing, plasma dantrolene concentration was measured spectrofluorometrically. On the basis of these results, 5 Thoroughbreds with RER from which food was withheld received dantrolene (4 mg/kg) or an inert treatment (water [20 mL]) orally 90 minutes before treadmill exercise (30 minutes, 5 d/wk) during two 3-week periods. Serum CK activity was determined 4 hours after exercise. Plasma dantrolene concentration was measured before and 90 minutes after dosing on the first and last days of dantrolene treatment and before dosing on the first day of the inert treatment period.

Results—90 minutes after dosing, mean ± SEM plasma dantrolene concentration was 0.62 ± 0.13 and 0 µg/mL in the dantrolene and inert treatment groups, respectively. Serum CK activity was lower in dantrolene- treated horses (264 ± 13 U/L), compared with activity in water-treated horses (1,088 ± 264 U/L). Two horses displayed marked muscle stiffness on the inert treatment.

Conclusions and Clinical Relevance—In 5 horses with RER from which food had been withheld, 4 mg of dantrolene/kg administered orally provided measurable, though variable, plasma concentrations and significantly decreased serum CK activity after exercise in 4 of those horses. (Am J Vet Res2004; 65:74–79)
Pulmonary epithelial lining fluid and plasma ascorbic acid concentrations in horses affected by recurrent airway obstruction
Authors: Deaton Christopher M. , Marlin David J. , Smith Nicola C. , Harris Pat A. , Roberts Colin A. , Schroter Robert C. , Kelly Frank J.
Published: December 2005

Objective—To determine the pulmonary epithelial lining
fluid (ELF) concentrations and degree of oxidation
of ascorbic acid in horses affected by recurrent airway
obstruction (RAO) in the presence and absence of
neutrophilic airway inflammation.

Animals—6 RAO-affected horses and 8 healthy control
horses.

Procedure—Nonenzymatic antioxidant concentrations
were determined in RBC, plasma, and ELF samples
of control horses and RAO-affected horses in the
presence and absence of airway inflammation.

Results—ELF ascorbic acid concentration was
decreased in RAO-affected horses with airway inflammation
(median, 0.06 mmol/L; 25th and 75th percentiles,
0.0 and 0.4 mmol/L), compared with RAOaffected
horses without airway inflammation (1.0
mmol/L; 0.7 and 1.5 mmol/L) and control horses
(2.2 mmol/L; 1.4 and 2.2 mmol/L). Epithelial lining fluid
ascorbic acid remained significantly lower in RAOaffected
horses without airway inflammation than in
control horses. Moreover, the ELF ascorbic acid redox
ratio (ie, ratio of the concentrations of dehydroascorbate
to total ascorbic acid) was higher in RAO-affected horses
with airway inflammation (median, 0.85; 25th and
75th percentiles, 0.25 and 1.00), compared with RAOaffected
horses without airway inflammation (0.04; 0.02
and 0.22). The number of neutrophils in bronchoalveolar
lavage fluid was inversely related to the ELF ascorbic
acid concentration ( r = –0.81) and positively correlated
with the ascorbic acid redox ratio ( r= 0.65).

Conclusions and Clinical Relevance—Neutrophilic
inflammation in horses affected by RAO is associated
with a reduction in the ELF ascorbic acid pool.
Nutritional supplementation with ascorbic acid derivatives
in horses affected by RAO is an area for further
investigation. ( Am J Vet Res2004;65:80–87)
Use of a polymerase chain reaction assay and an ELISA to monitor porcine circovirus type 2 infection in pigs from farms with and without postweaning multisystemic wasting syndrome
Authors: Sibila Marina , Calsamiglia Maria , Segalés Joaquim , Blanchard Philippe , Badiella Llorenç , Le Dimna Mireille , Jestin André , Domingo Mariano
Published: December 2005

Objective—To determine whether correlations exist between viremia with porcine circovirus type 2 (PCV2) and serum antibody profiles and between detection of PCV2 in nasal cavities and viremia of pigs from farms with and without postweaning multisystemic wasting syndrome (PMWS).

Animals—495 pigs, ranging from the late nursery stage to the early grower-finisher stage of production.

Procedure—Serum antibodies to PCV2 were studied with an ELISA that detects the ORF2 viral protein. Nasal swab specimens and serum samples were tested with a PCV2-specific PCR assay.

Results—PCV2 DNA and serum antibodies to PCV2 were detected in pigs from all farms, although in different proportions. Overall, PCV2 DNA was detected in greater percentages in serum samples and nasal swab specimens of pigs from farms with PMWS. Although viral DNA was detected in both serum samples and nasal swab specimens, PCV2 detection in nasal swab specimens was higher than in serum samples of pigs from all farms. Serum antibodies to PCV2 were detected in a greater percentage of pigs from farms with PMWS, compared with farms without PMWS.

Conclusions and Clinical Relevance—A high prevalence of PCV2 infection was found in pigs from farms with and without PMWS. Besides the presence of PCV2, unknown additional factors may be necessary to induce the full expression of PMWS. (Am J Vet Res2004;65:88–92)
Development of a polymerase chain reactionbased method to identify species-specific components in dog food
Authors: Myers Michael J. , Farrell Dorothy E. , Heller David N. , Yancy Haile F.
Published: December 2005

Objective—To determine whether there is a relationship
between species-specific mitochondrial DNA
(mtDNA), especially canine and feline mtDNA, and
detectable amounts of pentobarbital in previously
analyzed dog food samples.

Sample Population—31 dog food samples previously
analyzed for pentobarbital (limit of detection, 1 µg/kg).

Procedure—Polymerase chain reaction (PCR) analysis
was performed on dog food samples by use of
PCR primers specific for either canine, feline, equine,
bovine, porcine, ovine, or poultry mtDNA.

Results—PCR amplicons specific for feline or canine
mtDNA at a 0.007% (70 µg/g [wt/wt basis]) or
0.0007% (7 µg/g) level, respectively, were not found
in the 31 dog food samples. Most of the 31 dog food
samples had a PCR amplicon on PCR analysis when a
PCR primer set capable of simultaneously detecting
mtDNA of cows, pigs, sheep, goats, deer, elk, and
horses was used. Results of PCR analysis by use of
primers specific for bovine, swine, sheep and goat, or
horse mtDNA revealed amplicons specific for bovine
or swine mtDNA only in 27 of the 31 samples.
Analysis of the remaining 4 samples failed to yield
amplicons for any mammalian mtDNA. Pentobarbital
was detected in 2 of these 4 samples. Results of PCR
analysis correlated with the stated ingredient list for
most, but not all samples.

Conclusions and Clinical Relevance—Because
canine and feline mtDNA were not found in a set of
retail dog food samples, these results indicate that
the source of pentobarbital in dog food is something
other than proteins from rendered pet remains. ( Am J Vet Res 2004;65:99–103)
Effects of oral administration of tilmicosin on pulmonary inflammation in piglets experimentally infected with Actinobacillus pleuropneumoniae
Authors: Nerland Erin M. , LeBlanc Justin M. , Fedwick Jason P. , Morck Douglas W. , Merrill John K. , Dick Paul , Paradis Marie-Anne , Buret Andre G.
Published: December 2005

Objective—To determine the effects of oral administration of tilmicosin in piglets experimentally infected withActinobacillus pleuropneumoniae.

Animals—Forty 3-week-old specific-pathogen free piglets.

Procedure—Piglets were assigned to 1 of 4 groups as follows: 1) uninfected sham-treated control piglets; 2) infected untreated piglets that were intratracheally inoculated with 107CFUs of Apleuropneumoniae; 3) infected treated piglets that were intratracheally inoculated withA pleuropneumoniaeand received tilmicosin in feed (400 ppm [µg/g]) for 7 days prior to inoculation; or 4) infected treated piglets that were intratracheally inoculated with Apleuropneumoniaeand received chlortetracycline (CTC) in feed (1,100 ppm [µg/g]) for 7 days prior to inoculation. Bronchoalveolar lavage (BAL) fluid and lung tissue specimens of piglets for each group were evaluated at 3 or 24 hours after inoculation. For each time point, 4 to 6 piglets/group were studied.

Results—Feeding of CTC and tilmicosin decreased bacterial load in lungs of infected piglets. Tilmicosin delivered in feed, but not CTC, enhanced apoptosis in porcine BAL fluid leukocytes. This was associated with a decrease in LTB4concentrations in BAL fluid of tilmicosin-treated piglets, compared with untreated and CTC-treated piglets, and also with a significant decrease in the number of pulmonary lesions. Tilmicosin inhibited infection-induced increases in rectal temperatures, as measured in untreated and CTC-treated piglets. Pulmonary neutrophil infiltration and prostaglandin E2concentrations in the BAL fluid were not significantly different among groups at any time.

Conclusions and Clinical Relevance—Oral administration of tilmicosin to infected piglets induces apoptosis in BAL fluid leukocytes and decreases BAL fluid LTB4concentrations and inflammatory lung lesions. (Am J Vet Res2005;66:100–107)
Epidemiologic evaluation of diarrhea in dogs in an animal shelter
Authors: Sokolow Susanne H. , Rand Courtney , Marks Stanley L. , Drazenovich Niki L. , Kather Elizabeth J. , Foley Janet E.
Published: December 2005

Objective—To determine associations among infectious pathogens and diarrheal disease in dogs in an animal shelter and demonstrate the use of geographic information systems (GISs) for tracking spatial distributions of diarrheal disease within shelters.

Sample Population—Feces from 120 dogs.

Procedure—Fresh fecal specimens were screened for bacteria and bacterial toxins via bacteriologic culture and ELISA, parvovirus via ELISA, canine coronavirus via nested polymerase chain reaction assay, protozoal cysts and oocysts via a direct fluorescent antibody technique, and parasite ova and larvae via microscopic examination of direct wet mounts and zinc sulfate centrifugation flotation.

Results—Salmonella entericaandBrachyspiraspp were not common, whereas other pathogens such as canine coronavirus andHelicobacterspp were common among the dogs that were surveyed. Only intestinal parasites andCampylobacter jejuniinfection were significant risk factors for diarrhea by univariate odds ratio analysis.Giardia lambliawas significantly underestimated by fecal flotation, compared with a direct fluorescent antibody technique. Spatial analysis of case specimens by use of GIS indicated that diarrhea was widespread throughout the entire shelter, and spatial statistical analysis revealed no evidence of spatial clustering of case specimens.

Conclusions and Clinical Relevance—This study provided an epidemiologic overview of diarrhea and interacting diarrhea-associated pathogens in a densely housed, highly predisposed shelter population of dogs. Several of the approaches used in this study, such as use of a spatial representation of case specimens and considering multiple etiologies simultaneously, were novel and illustrate an integrated approach to epidemiologic investigations in shelter populations. (Am J Vet Res2005;66:1018–1024)
Effects of oral administration of levothyroxine sodium on serum concentrations of thyroid gland hormones and responses to injections of thyrotropin-releasing hormone in healthy adult mares
Authors: Sommardahl Carla S. , Frank Nicholas , Elliott Sarah B. , Webb Latisha L. , Refsal Kent R. , Denhart Joseph W. , Thompson Donald L.
Published: December 2005

Objective—To determine the effects of levothyroxine sodium (L-T4) on serum concentrations of thyroid gland hormones and responses to injections of thyrotropin-releasing hormone (TRH) in euthyroid horses.

Animals—12 healthy adult mares.

Procedure—8 horses received an incrementally increasing dosage of L-T4(24, 48, 72, or 96 mg of L-T4/d) for weeks 1 to 8. Each dose was provided for 2 weeks. Four additional horses remained untreated. Serum concentrations of total triiodothyronine (tT3), total thyroxine (tT4), free T3(fT3), free T4(fT4), and thyroid- stimulating hormone (TSH) were measured in samples obtained at weeks 0, 2, 4, 6, and 8; 1.2 mg of TRH was then administered IV, and serum concentrations of thyroid gland hormones were measured 2 and 4 hours after injection. Serum reverse T3(rT3) concentration was also measured in the samples collected at weeks 0 and 8.

Results—Treated horses lost a significant amount of weight (median, 19 kg). Significant treatment-by-time effects were detected for serum tT3, tT4, fT3, fT4, and TSH concentrations, and serum tT4concentrations were positively correlated ( r, 0.95) with time (and therefore dosage) in treated horses. Mean ± SD serum rT3concentration significantly increased in treated horses (3.06 ± 0.51 nmol/L for week 8 vs 0.74 ± 0.22 nmol/L for week 0). Serum tT3, tT4, fT3, and TSH concentrations in response to TRH injections differed significantly between treated and untreated horses.

Conclusions and Clinical Relevance—Administration of levothyroxine sodium increased serum tT4concentrations and blunted responses to TRH injection in healthy euthyroid horses. (Am J Vet Res2005;66:1025–1031)
Effects of oral administration of levothyroxine sodium on concentrations of plasma lipids, concentration and composition of very-low-density lipoproteins, and glucose dynamics in healthy adult mares
Authors: Frank Nicholas , Sommardahl Carla S. , Eiler Hugo , Webb Latisha L. , Denhart Joseph W. , Boston Ray C.
Published: December 2005

Objective—To evaluate glucose and lipid metabolism in healthy adult horses administered levothyroxine sodium (L-T4).

Animals—12 healthy adult mares.

Procedure—8 horses received an incrementally increasing dosage of L-T4(24, 48, 72, or 96 mg of L-T4/d) for weeks 1 to 8. Each dose was provided between 7 AM and 8 AM in the morning grain meal for 2 weeks. Four additional horses remained untreated. Serum concentrations of nonesterified fatty acids, triglyceride (TG), total cholesterol (TC), and very-low-density lipoprotein (VLDL) were measured and composition of VLDL examined in samples obtained between 8 AM and 9 AM at weeks 0, 2, 4, 6, and 8. Glucose dynamics were assessed by use of a combined IV glucose-insulin tolerance test (IVGITT) conducted before and at the end of the 8-week treatment period. Data for each combined IVGITT were interpreted by use of the minimal model.

Results—Plasma TG, TC, and VLDL concentrations significantly decreased over time in treated horses. At the completion of the 8-week treatment period, mean plasma VLDL concentration was 46% of the mean value for week 0 in treated horses. Insulin sensitivity significantly increased (> 2-fold) in treated horses, but glucose effectiveness and net insulin response were not affected. Levothyroxine sodium significantly increased the rate of insulin disposal.

Conclusions and Clinical Relevance—Administration of L-T4decreases blood lipid concentrations, improves insulin sensitivity, and increases insulin disposal in horses. Levothyroxine sodium may have potential as a treatment for horses with reduced insulin sensitivity. (Am J Vet Res2005;66:1032–1038)
Effect of mild restriction of food intake on the speed of racing Greyhounds
Authors: Hill Richard C. , Lewis Daniel D. , Randell Susan C. , Scott Karen C. , Omori Mayuko , Sundstrom Deborah A. , Jones Galin L. , Speakman John R. , Butterwick Richard F.
Published: December 2005

Objective—To determine whether mild restriction of food intake affects clinicopathologic variables, body composition, and performance of dogs undertaking intense sprint exercise.

Animals—9 trained healthy adult Greyhounds.

Procedure—Dogs were offered food free choice once daily for 9 weeks until body weight and food intake stabilized. Dogs were then randomly assigned to be fed either 85% or 100% of this quantity of food in a crossover study (duration of each diet treatment period, 9 weeks). Dogs raced a distance of 500 m twice weekly. Clinicopathologic variables were assessed before and 5 minutes after racing; food intake, weight, body composition, body condition score, and race times were compared at the end of each diet period.

Results—Compared with values associated with unrestricted access to food, there were significant decreases in mean body weight (by 6%) and median body condition score (from 3.75 to 3.5 on a 9-point scale) and the mean speed of the dogs was significantly faster (by 0.7 km/h) when food intake was restricted. Body composition and most clinicopathologic variables were unaffected by diet treatment, but dogs given restricted access to food had slightly fewer neutrophils, compared with values determined when food intake was unrestricted.

Conclusions and Clinical Relevance—Results indicate that the common practice among Greyhound trainers of mildly restricting food intake of racing dogs to reduce body weight does improve sprint performance. A body condition score of approximately 3.5 on a 9-point scale is normal for a trained Greyhound in racing condition. (Am J Vet Res2005;66:1065–1070)
Multivariate meta-analysis of pharmacokinetic studies of ampicillin trihydrate in cattle
Authors: Gehring Ronette , van der Merwe Deon , Pierce Alice N. , Baynes Ronald E. , Craigmill Arthur L. , Riviere Jim E.
Published: December 2005

Objective—To investigate the feasibility of using multivariate
cluster analysis to meta-analyze pharmacokinetic
data obtained from studies of pharmacokinetics
of ampicillin trihydrate in cattle and identify factors
that could account for variability in pharmacokinetic
parameters among studies.

Sample Population—Data from original studies of
the pharmacokinetics of ampicillin trihydrate in cattle
in the database of the Food Animal Residue
Avoidance Databank.

Procedure—Mean plasma or serum ampicillin concentration
versus time data and potential factors that
may have affected the pharmacokinetics of ampicillin
trihydrate were obtained from each study.
Noncompartmental pharmacokinetic analyses were
performed, and values of pharmacokinetic parameters
were clustered by use of multivariate cluster
analysis. Practical importance of the clusters was
evaluated by comparing the frequency of factors that
may have affected the pharmacokinetics of ampicillin
trihydrate among clusters.

Results—A single cluster with lower mean values for
clearance and volume of distribution of ampicillin trihydrate
administered PO, compared with other clusters,
was identified. This cluster included studies that
used preruminant calves in which feeding was withheld
overnight and calves to which probenecid had
been administered concurrently.

Conclusions and Clinical Relevance—Meta-analysis
was successful in detecting a potential subpopulation
of cattle for which factors that explained differences in
pharmacokinetic parameters could be identified.
Accurate estimates of pharmacokinetic parameters
are important for the calculation of dosages and
extended withdrawal intervals after extralabel drug
administration. (Am J Vet Res 2005;66:108–112)
Comparison of susceptibility of fungal isolates to lufenuron and nikkomycin Z alone or in combination with itraconazole
Authors: Hector Richard F. , Davidson Autumn P. , Johnson Suzanne M.
Published: December 2005

Objective—To evaluate and compare the in vitro antifungal
properties of lufenuron and nikkomycin Z
against isolates of Coccidioides immitis and
Aspergillus fumigatus when used singly and in combination
with the azole antifungal agent itraconazole.

Sample Population—3 clinical isolates of A fumigatus and
the Silveira strain of C immitis.

Procedure—The fungal isolates were tested in vitro
for susceptibility to the single and combination of
compounds by use of microtiter-format susceptibility
methods. Minimum inhibitory concentration end
points were determined visually, and the contents of
representative wells were examined microscopically
for evidence of morphologic effects on fungi.

Results—No evidence of inhibition, either by susceptibility
testing or direct microscopic examination of
treated cells, was obtained with lufenuron under
experimental conditions. In contrast, nikkomycin Z, a
known inhibitor of fungal chitin synthesis, had potent
activity against C immitis when used singly. A synergistic
interaction between nikkomycin Z and itraconazole
was found against isolates of both species tested.

Conclusions and Clinical Relevance—On the basis of
our in vitro data, lufenuron does not appear to possess
antifungal properties. ( Am J Vet Res 2005;66:1090–1093)
Expression of interleukin-10 and suppressor of cytokine signaling-3 associated with susceptibility of cattle to infection with Mycobacterium avium subsp paratuberculosis
Authors: Weiss Douglas J. , Evanson Oral A. , Souza Cleverson D.
Published: December 2005

Objective—To determine functional characteristics of
monocytes obtained from cows with subclinical infection
with Mycobacterium avium subsp paratuberculosis
(MAP) that may have predisposed those cows to
becoming infected with MAP.

Sample Population—Monocytes obtained from 5
uninfected cows and 5 cows subclinically infected
with MAP in a herd with a high prevalence of paratuberculosis
(ie, Johne's disease).

Procedures—Monocytes from uninfected and subclinically
infected cows were incubated with MAP for
2, 6, 24, 72, or 96 hours. Variables measured included
expression of tumor necrosis factor-α (TNF-α), interleukin
(IL)-10, IL-12, transforming growth factor-β, and
suppressor of cytokine signaling-3 (SOCS-3); apoptosis
of monocytes; acidification of phagosomes; and
killing of MAP.

Results—Monocytes from infected cows had greater
expression of IL-10 and SOCS-3 at 2 hours of coincubation
with MAP and lower expression of TNF-α and
IL-12 when results for all incubation times were combined.
Monocytes from infected cows had a greater
capacity to acidify phagosomes. No differences were
observed in the rate of apoptosis or capacity of monocytes
to kill MAP organisms.

Conclusions and Clinical Relevance—Monocytes
obtained from cows with subclinical infection with
MAP had upregulated expression of IL-10 and
SOCS-3 within the first 2 hours after exposure to MAP
organisms. Although this did not inhibit acidification of
phagosomes, apoptosis of monocytes, or attenuation
of the capacity to kill MAP organisms, it may have
attenuated the capacity of mononuclear phagocytes to
initiate inflammatory and adaptive immune responses.
(Am J Vet Res 2005;66:1114–1120)
Development of a genetically modified nontoxigenic Pasteurella multocida toxin as a candidate for use in vaccines against progressive atrophic rhinitis in pigs
Authors: To Ho , Someno Shuichi , Nagai Shinya
Published: December 2005

Objective—To construct a genetically modified nontoxigenic
Pasteurella multocida toxin (PMT) and
examine its immunoprotective activity against challenge
exposure with wild-type PMT in pigs.

Animals—5 healthy pigs.

Procedure—A nontoxigenic PMT was created by
replacing the serine at position 1164 with alanine
(S1164A) and the cysteine at position 1165 with serine
(C1165S). Toxic activity was determined by use of the
guinea pig skin test and mouse lethality test. Three
pigs were vaccinated twice with the modified PMT,
and the remaining 2 pigs served as nonvaccinated
control animals. Vaccinated and control pigs were
challenge exposed with wild-type PMT. Pigs were
euthanatized and necropsied on day 14 after challenge
exposure. Turbinate atrophy was examined
macroscopically and assigned a score. Serum anti-
PMT antibodies were determined by use of an ELISA.

Results—The genetically modified PMT was characterized
by a total lack of toxic activity. Pigs vaccinated
with the modified PMT became seropositive; in contrast,
control pigs remained seronegative. Necropsy
revealed that the 2 control pigs had moderate and
severe turbinate atrophy, respectively, whereas the 3
vaccinated pigs did not have any lesions in the
turbinates or abnormalities in other organs.

Conclusions and Clinical Relevance—Modification
by use of S1164A and C1165S leads to a complete loss
of toxic effects of PMT without impairment of the ability
to induce protective immunity in pigs. Analysis of
these results suggests that genetically modified PMT
may represent a good candidate for use in developing
a vaccine against progressive atrophic rhinitis in pigs.
(Am J Vet Res 2005;66:113–118)
Effect of a silicone-containing dressing on exuberant granulation tissue formation and wound repair in horses
Authors: Ducharme-Desjarlais Marilys , Céleste Christophe J. , Lepault Élodie , Theoret Christine L.
Published: December 2005

Objective—To determine the effect of a silicone dressing on the rate and quality of repair of limb wounds and compare microvascular occlusion and apoptosis in wounds treated with the silicone dressing and those treated with a conventional dressing in horses.

Animals—5 horses.

Procedure—Horses received two 6.25-cm2wounds on each metacarpus. Ten wounds were treated with a silicone dressing; the other 10 were treated with a control dressing. Quality of repair and wound size were evaluated at each bandage change. Time to healing and the number of excisions of exuberant granulation tissue were recorded. Biopsy specimens taken from healed wounds were evaluated semiquantitatively via histologic examination, p53 immunohistochemical analysis, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) to quantify apoptosis, and electron microscopic examination to measure microvessel luminal diameters.

Results—The silicone dressing surpassed the conventional dressing in preventing formation of exuberant granulation tissue and improving tissue quality. Microvessels were occluded significantly more often in wounds dressed with the silicone gel, which also diminished the expression of mutant p53, an indirect inhibitor of apoptosis, although greater apoptosis was not confirmed quantitatively by use of TUNEL.

Conclusions and Clinical Relevance—Because the silicone dressing inhibited the formation of exuberant granulation tissue, it may be integrated in a management strategy designed to improve the repair of limb wounds in horses. (Am J Vet Res2005;66:1133–1139)
Pharmacokinetics of lidocaine and its active metabolite, monoethylglycinexylidide, after intravenous administration of lidocaine to awake and isoflurane-anesthetized cats
Authors: Thomasy Sara M. , Pypendop Bruno H. , Ilkiw Jan E. , Stanley Scott D.
Published: December 2005

Objective—To describe the pharmacokinetics of lidocaine
and its active metabolite, monoethylglycinexylidide
(MEGX), after IV administration of a single bolus
of lidocaine in cats that were awake in phase 1 and
anesthetized with isoflurane in phase 2 of the study.

Animals—8 healthy adult cats.

Procedure—During phase 1, cats were administered
lidocaine (2 mg/kg, IV) as a bolus injection (time 0).
During phase 2, cats were anesthetized with isoflurane
and maintained at 0.75 times the minimum alveolar
concentration of isoflurane for each specific cat.
After a 15-minute equilibration period, lidocaine
(2 mg/kg, IV) was administered as a bolus injection to
each cat (time 0). In both phases, plasma concentrations
of lidocaine and MEGX were measured at various
time points by use of liquid chromatography-mass
spectrometry.

Results—Anesthesia with isoflurane significantly
decreased the volume of the central compartment,
clearance, and elimination half-life of lidocaine and significantly
increased the extrapolated plasma drug concentration
at time 0, compared with values for awake
cats. Pharmacokinetics of MEGX were also changed by
isoflurane-induced anesthesia because the maximum
observed plasma concentration (Cmax), area under the
concentration-time curve extrapolated to infinity, and
time to Cmax were significantly higher in anesthetized
cats, compared with values for awake cats.

Conclusions and Clinical Relevance—Pharmacokinetics
of lidocaine and MEGX were substantially
altered in cats anesthetized by use of isoflurane.
When pharmacokinetic variables are used to determine
loading and infusion doses in awake or anesthetized
cats, they should be measured in cats that
are awake or anesthetized, respectively. (Am J Vet
Res 2005;66:1162–1166)
Effects of tension of the girth strap on respiratory system mechanics in horses at rest and during hyperpnea induced by administration of lobeline hydrochloride
Authors: Hoffman Andrew M. , Swanson Lisa G. , Bruns Susan J. , Kuehn Heike , Bedenice Daniela
Published: December 2005

Objective—To determine whether tension of the girth strap of a saddle would sufficiently affect rib motion and reduce lung volume to alter pulmonary resistance in horses.

Animals—10 healthy adult horses.

Procedure—We used classical techniques to measure the effects of tightening a girth strap (15 kg of tension) on pulmonary dynamics during eupnea and hyperpnea in horses. Respiratory impedance was evaluated by use of oscillometry, and resistance and reactance data were partitioned into lung and chest wall components. Rib cage and abdominal contributions to tidal volume and minute ventilation were measured by use of respiratory inductance plethysmography. Effects of strap tension on functional residual capacity (FRC) were measured during eupnea by use of a helium-dilution technique. In a subgroup of 6 horses, we also measured transdiaphragmatic pressures during eupnea and hyperpnea induced by administration of lobeline hydrochloride (0.2 mg/kg, IV).

Results—Pulmonary resistance measured by use of oscillometry but not by use of classical methods was significantly increased by the tension of the girth strap. However, the increase in pulmonary resistance could not be explained by a decrease in FRC. Motion of the rib cage was significantly reduced during eupnea and hyperpnea. However, ventilatory variables (tidal volume, minute ventilation, and peak flows), FRC, and transdiaphragmatic pressures were unaltered by strap tension.

Conclusions and Clinical Relevance—Although tension of the girth strap caused measurable changes in respiratory mechanics (loss of rib motion and increased pulmonary resistance), there was no evidence that ventilation was limited. (Am J Vet Res2005;66:1167–1174)
Influence of age, site, and degenerative state on the speed of sound in equine articular cartilage
Authors: Brommer Harold , Laasanen Mikko S. , Brama Pieter A. J. , Weeren P. René van , Barneveld Ab , Helminen Heikki J. , Jurvelin Jukka S.
Published: December 2005

Objective—To determine the speed of sound (SOS) in equine articular cartilage and investigate the influence of age, site in the joint, and cartilage degeneration on the SOS.

Sample Population—Cartilage samples from 38 metacarpophalangeal joints of 38 horses (age range, 5 months to 22 years).

Procedure—Osteochondral plugs were collected from 2 articular sites of the proximal phalanx after the degenerative state was characterized by use of the cartilage degeneration index (CDI) technique. The SOS was calculated (ratio of needle-probe cartilage thickness to time of flight of the ultrasound pulse), and relationships between SOS value and age, site, and cartilage degeneration were evaluated. An analytical model of cartilage indentation was used to evaluate the effect of variation in true SOS on the determination of cartilage thickness and dynamic modulus with the ultrasound indentation technique.

Results—The mean SOS for all samples was 1,696 ± 126 m/s. Age, site, and cartilage degeneration had no significant influence on the SOS in cartilage. The analytical model revealed that use of the mean SOS of 1,696 m/s was associated with maximum errors of 17.5% on cartilage thickness and 7.0% on dynamic modulus in an SOS range that covered 95% of the individual measurements.

Conclusions and Clinical Relevance—In equine articular cartilage, use of mean SOS of 1,696 m/s in ultrasound indentation measurements introduces some inaccuracy on cartilage thickness determinations, but the dynamic modulus of cartilage can be estimated with acceptable accuracy in horses regardless of age, site in the joint, or stage of cartilage degeneration. (Am J Vet Res2005;66:1175–1180)
Effects of proinflammatory cytokines on canine articular chondrocytes in a three-dimensional culture
Authors: Kuroki Keiichi , Stoker Aaron M. , Cook James L.
Published: December 2005

Objective—To determine the effects of interleukin
(IL)-1 and tumor necrosis factor (TNF)-α on canine
chondrocytes cultured in an agarose-based 3-dimensional
(3-D) system.

Sample Population—Humeral head articular cartilage
chondrocytes obtained from 6 adult dogs.

Procedure—Chondrocytes were cultured in a 3-D
system for ≤ 12 days in serum-free medium with IL-1α, IL-1β,
or TNF-α at concentrations of 20, 50, or
100 ng/mL. After 1, 3, 6, and 12 days, glycosaminoglycan
(GAG) concentrations in 3-D constructs; nitric
oxide and prostaglandin E2 (PGE2) concentrations in
media samples; and relative expressions of selected
genes, including metalloproteinase (MMP)-13 and tissue
inhibitor of metalloproteinase (TIMP)-1 and TIMP-2, were
evaluated. Control specimens were comprised
of chondrocytes cultured without proinflammatory
cytokines.

Results—In control 3-D constructs, GAG content was
significantly higher than for all other constructs.
Compared with control values, relative expressions of
MMP-13, TIMP-1, and TIMP-2 genes in the IL-1β
(50 ng/mL) group were significantly higher at day 1; at
all evaluations, media concentrations of nitric oxide
were significantly higher in all TNF-α–treated cultures;
and concentrations of PGE2 in media samples were
significantly higher in the IL-1β (50 ng/mL) and IL-1β
(100 ng/mL) groups at days 1 and 3, in the IL-1β
(100 ng/mL) group at day 6, and in all TNF-α groups at
days 1, 3, and 6.

Conclusions and Clinical Relevance—Results suggested
that TNF-α more readily induces production of
nitric oxide and PGE2 by canine chondrocytes, compared
with IL-1β. In vitro, IL-1α appeared to have a
minimal effect on canine chondrocytes. (Am J Vet Res
2005;66:1187–1196)
Use of real-time reverse transcriptase polymerase chain reaction assay and cell culture methods for detection of swine influenza A viruses
Authors: Landolt Gabriele A. , Karasin Alexander I. , Hofer Christian , Mahaney Julie , Svaren John , Olsen Christopher W.
Published: December 2005

Objective—To evaluate sensitivity and specificity of a
real-time reverse transcriptase polymerase chain
reaction (RT-PCR) assay performed on pooled nasal
swab specimens, compared with virus isolation performed
on individual nasal swab specimens by use of
2 cell culture lines for detection of swine influenza A
viruses.

Sample Population—900 nasal swab specimens
obtained from pigs at an abattoir and 62 nasal swab
specimens submitted for diagnostic testing.

Procedure—Primers were chosen to amplify a conserved
portion of the influenza virus matrix gene.
Assay sensitivity was initially determined by testing
serial dilutions of various subtypes of swine influenza
viruses. Sensitivity and specificity were confirmed by
use of nasal swab specimens with or without addition
of known concentrations of influenza virus and further
validated by testing nasal swab specimens obtained
through an abattoir surveillance program or submitted
for diagnostic testing. Aliquots of specimens were
pooled in sets of 10, and results of real-time RT-PCR
assays were compared with results of virus isolation
of individual specimens in Madin Darby canine kidney
(MDCK) and mink lung (Mv1Lu) cells.

Results—Real-time RT-PCR assay was highly specific
(100%) and sensitive (88% to 100%). Among the 16
viruses isolated, 3 grew only in Mv1Lu cells and 3
grew only in MDCK cells.

Conclusions and Clinical Relevance—Results indicate
that real-time RT-PCR assay is a fast and accurate
test for screening numerous nasal swab specimens for
swine influenza virus. Some viruses were isolated in
only MDCK or Mv1Lu cells, indicating that use of
> 1 cell line may be required to isolate a broad range of
influenza A viruses. (Am J Vet Res 2005;66:119–124)
Effect of exercise on proglycogen and macroglycogen content in skeletal muscles of pigs with the Rendement Napole mutation
Authors: Essén-Gustavsson Birgitta , Jensen-Waern Marianne , Jonasson Robert , Andersson Leif
Published: December 2005

Objective—To investigate influence of the
Rendement Napole (RN–) mutation on proglycogen
(PG) and macroglycogen (MG) content in skeletal
muscles before and after exercise and evaluate glycogen
concentrations within various muscle fiber types.

Animals—5 pigs with the RN– mutation and 3 noncarrier
pigs.

Procedure—Pigs performed 2 exercise tests on a
treadmill. In the first, pigs (mean body weight, 27 kg)
ran a distance of approximately 800 m. In the second,
pigs (mean body weight, 63 kg) ran until fatigued.
Biopsy specimens (biceps femoris muscle) for determination
of PG and MG contents were obtained
before and after exercise, 24 hours after the first test,
and 3 hours after the second test. Histochemical
analysis was performed on specimens obtained
before and after the second test.

Results—Before exercise, PG stores did not differ
markedly between groups, but MG stores were
twice as high in pigs with the RN– mutation, compared
with noncarrier pigs. The MG content
decreased to a similar extent in both groups after
exercise. Resynthesis of MG was greater in pigs with
the RN– mutation than in noncarrier pigs by 3 hours
after exercise. A low glycogen content after exercise
was observed in many type I and type IIA fibers and
in some type IIB fibers.

Conclusions and Clinical Relevance—The RN– mutation
was associated with high MG stores in skeletal
muscle that did not influence exercise performance.
The RN– mutation did not impair glycogenolysis during
exercise but may induce faster resynthesis of MG
after exercise. (Am J Vet Res 2005;66:1197–1201)
Characterization of the in vitro responses of equine cecal longitudinal smooth muscle to endothelin-1
Authors: Chidambaram Ramaswamy M. , Eades Susan C. , Moore Rustin M. , Hosgood Giselle , Venugopal Changaram S.
Published: December 2005

Objective—To characterize the in vitro response of equine cecal longitudinal smooth muscle (CLSM) to endothelin (ET)-1 and assess the role of ETAand ETBreceptors in those ET-1–induced responses.

Animals—36 horses without gastrointestinal tract disease.

Procedure—To determine cumulative concentrationresponse relationships, CLSM strips were suspended in tissue baths containing graded concentrations of ET-1 (10–9to 10–6M) with or without BQ-123 (ETAreceptor antagonist); with or without IRL-1038 (ETBreceptor antagonist); or with both antagonists at concentrations of 10–9, 10–7, and 10–5M. To determine the percentage change in baseline tension of CLSM, the areas under the curve during the 3-minute periods before and after addition of each dose were compared . Also, the effects of ET-1 and a combination of selective ETAand ETBreceptor antagonists on electrically evoked contractions were studied.

Results—ET-1 caused sustained increases in CLSM tension in a concentration-dependent manner. Contractile responses to ET-1 were not significantly inhibited by either BQ-123 or IRL-1038 alone at any concentration; however, responses were significantly inhibited by exposure to the antagonists together at a concentration of 10–5M. Electrical field stimulation did not change the spontaneous contractile activity of CLSM and did not significantly alter the tissue response to ET-1, BQ-123, or IRL-1038.

Conclusions and Clinical Relevance—Results indicated that ET-1 has a contractile effect on equine CLSM that is mediated via ETAand ETBreceptors. In vitro spontaneous contractions of equine CLSM apparently originate in the smooth muscle and not the enteric nervous system. (Am J Vet Res2005;66:1202–1208)