bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of variations in SzP proteins of Streptococcus equi subspecies zooepidemicus and the relationship between protein variants and clinical signs of infection in horses
Authors: Walker Richard L. , Runyan Catherine A.
Published: December 2005

Objective—To determine whether previously unidentified variations of the SzP protein ofStreptococcus equisubspzooepidemicuswere present in horses with various clinical signs of infection and whether any relationship could be identified between SzP protein variants and naturally occurring clinical conditions.

Sample Population—23 isolates ofS equisubspzooepidemicuswere recovered from specimens of horses with various clinical conditions and used as a representative population of isolates for evaluation of different SzP protein variants.

Procedure—Genetic heterogeneity of the isolates was demonstrated by repetitive extragenic palindromic- polymerase chain reaction analysis. TheSzPgene was sequenced and the presumed protein sequence determined for each isolate. Characteristics of the SzP proteins were compared among the isolates and in relation to the clinical conditions of horses from which they were recovered.

Results—The signal peptide types, number of proline- glutamic acid-proline-lysine repeats, and anchor sequences were consistent with those previously described for the SzP protein. Many of the isolates clustered with 5 previously described types on the basis of the hypervariable region of the SzP protein. One additional variant, which represented 8 of the isolates, was identified. Particular motifs in the hypervariable region accounted for many of the differences among hypervariable types.

Conclusions and Clinical Relevance—The SzP protein appears to be limited to a selected number of types. Variations in the SzP protein are frequently determined on the basis of different motifs rather than random amino acid substitutions. There does not appear to be any association of SzP protein variations and clinical manifestations of infection in horses. (Am J Vet Res2003;64:976–981)
Detection of apoptotic cells in intestines from horses with and without gastrointestinal tract disease
Authors: Rowe Emma L. , White Nathaniel A. , Buechner-Maxwell Virginia , Robertson John L. , Ward Daniel L.
Published: December 2005

Objective—To identify apoptosis in equine intestines and determine whether apoptosis is associated with gastrointestinal tract disease or a specific tissue layer of intestine.

Animals—38 horses that underwent surgery or were euthanatized for small or large intestine obstruction, strangulation, or distension and 9 control horses euthanatized for reasons other than gastrointestinal tract disease or systemic disease.

Procedure—Specimens were collected at surgery from intestine involved in the primary lesion and distant to the primary lesion site or at necropsy from several sites including the primary lesion site. Histologic tissue sections were stained with H&E, and apoptosis was detected by use of the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling technique. The number of apoptotic cells per hpf was counted in the mucosa, circular muscle, longitudinal muscle, and serosa.

Results—Apoptotic nuclei were seen in all layers of intestine. An increased number of apoptotic cells was found in the circular muscle of the intestine from horses with simple obstruction, compared with strangulating obstruction or healthy intestine. Intestine distant from a primary strangulating lesion had higher numbers of apoptotic cells than did intestine distant from a simple obstructive lesion or intestine taken at the site of a strangulating or simple obstructive lesion.

Conclusions and Clinical Relevance—Intestine from horses with obstructing or strangulating lesions in the small intestine and large colon had high numbers of apoptotic cells possibly because of ischemic cell injury and subsequent inflammation. Whether substantial apoptosis affects intestinal function is not yet known. (Am J Vet Res2003;64:982–988)
Isolation and characterization of factor I of the bovine complement system
Authors: Menger Marilyn , Aston W. Peter
Published: December 2005

Objective—To isolate and characterize factor I of the bovine complement system.

Sample Population—Serum obtained from the blood of beef cattle.

Procedures—Serum samples were fractionated to yield factor I by means of sequential precipitation, ionexchange, and gel-filtration chromatography. The protein was identified throughout the procedure on the basis of its ability to degrade the α'-chain of bovine C3b in the presence of bovine factor H. Electrophoresis in polyacrylamide gels was used to assess the degradation of C3b and determine the molecular weights of factor I and its component polypeptide chains.

Results—Bovine factor I had an apparent molecular weight of 94 kd and consisted of 2 disulfide-bonded polypeptides that had apparent molecular weights of 51 and 42 kd (under reducing conditions). Factor H was required for the factor I cleavage of the α'-chain of bovine C3b into iC3b. A similar cofactor effect was provided by trypsinized bovine erythrocytes or erythrocyte ghosts. Bovine properdin was prepared and shown to be a single polypeptide chain of 58 kd in the reduced form.

Conclusions and Clinical Relevance—Bovine factor I can be purified from serum by a simple 4-step procedure. It is structurally and functionally comparable to factor I of other species, and its purification completes the isolation and characterization of all the soluble components of the bovine alternative complement pathway. (Am J Vet Res2003;64:989–993)
Intracranial elastance in isoflurane-anesthetized horses
Authors: Brosnan Robert J. , LeCouteur Richard A. , Steffey Eugene P. , Imai Ayako , Farver Thomas B.
Published: December 2005

Objective—To determine whether high intracranial
pressure (ICP) during spontaneous ventilation (SV) in
anesthetized horses coincides with an increase in
intracranial elastance (ie, change in ICP per unit
change of intracranial volume).

Animals—6 adult horses.

Procedure—Anesthesia was induced and maintained
in each horse for 5 hours with isoflurane at a constant
dose equal to 1.2 times the minimum alveolar concentration.
Direct ICP measurements were obtained
by use of a strain gauge transducer inserted in the
subarachnoid space, and arterial blood pressure was
measured from a carotid artery. Physiologic responses
were recorded after 15 minutes of normocapnic
controlled ventilation (CV) and then after 10 minutes
of SV. Aliquots (3 mL) of CSF were removed from
each horse during SV until ICP returned to CV values.
Slopes of pressure-volume curves yielded intracranial
elastance.

Results—Intracranial elastance ranged from 0.2 to
3.7 mm Hg/mL after removal of the first aliquot of
CSF. Slopes of pressure-volume curves were largest
following removal of the initial CSF aliquot, but shallow
portions of curves were detected at relatively
high ICPs (25 to 35 mm Hg). A second-order relationship
between SV ICP and initial intracranial elastance
was found.

Conclusions and Clinical Relevance—In horses
anesthetized with isoflurane, small changes in intracranial
volume can cause large changes in ICP. Increased
intracranial elastance could further exacerbate preexisting
intracranial hypertension. However, removal of
small volumes of CSF may cause rapid compensatory
replacement from other intracranial compartments,
which suggests steady-state maintenance of an
increase in intracranial volume during isoflurane anesthesia
in horses. (Am J Vet Res 2004;65:1042–1046)
Risk of postnatal exposure to Sarcocystis neurona and Neospora hughesi in horses
Authors: Duarte Paulo de C. , Conrad Patricia A. , Wilson W. David , Ferraro Gregory L. , Packham Andrea E. , Bowers-Lepore Jeanne , Carpenter Tim E. , Gardner Ian A.
Published: December 2005

Objective—To estimate risk of exposure and age at first exposure toSarcocystis neuronaandNeospora hughesiand time to maternal antibody decay in foals.

Animals—484 Thoroughbred and Warmblood foals from 4 farms in California.

Procedure—Serum was collected before and after colostrum ingestion and at 3-month intervals thereafter. Samples were tested by use of the indirect fluorescent antibody test; cutoff titers were ≥ 40 and ≥ 160 forS neuronaandN hughesi, respectively.

Results—Risk of exposure toS neuronaandN hughesiduring the study were 8.2% and 3.1%, respectively. Annual rate of exposure was 3.1% forS neuronaand 1.7% forN hughesi. There was a significant difference in the risk of exposure toS neuronaamong farms but not in the risk of exposure toN hughesi. Median age at first exposure was 1.2 years forS neuronaand 0.8 years forN hughesi. Highest prevalence of antibodies againstS neuronaandN hughesiwas 6% and 2.1%, respectively, at a mean age of 1.7 and 1.4 years, respectively. Median time to maternal antibody decay was 96 days forS neuronaand 91 days forN hughesi. There were no clinical cases of equine protozoal myeloenchaphlitis (EPM).

Conclusions and Clinical Relevance—Exposure toS neuronaandN hughesiwas low in foals between birth and 2.5 years of age. Maternally acquired antibodies may cause false-positive results for 3 or 4 months after birth, and EPM was a rare clinical disease in horses ≤ 2.5 years of age. (Am J Vet Res2004;65:1047–1052)
Assessment of the influence of fatty acids on indices of insulin sensitivity and myocellular lipid content by use of magnetic resonance spectroscopy in cats
Authors: Wilkins Caroline , Long Robert C. , Waldron Mark , Ferguson Duncan C. , Hoenig Margarethe
Published: December 2005

Objective—To determine whether dietary fatty acids affect indicators of insulin sensitivity, plasma insulin and lipid concentrations, and lipid accumulation in muscle cells in lean and obese cats.

Animals—28 neutered adult cats.

Procedure—IV glucose tolerance tests and magnetic resonance imaging were performed before (lean phase) and after 21 weeks of ad libitum intake of either a diet high in omega-3 polyunsaturated fatty acids (3-PUFAs; n = 14) or high in saturated fatty acids (SFAs; 14).

Results—Compared with the lean phase, ad libitum food intake resulted in increased weight, body mass index, girth, and percentage fat in both groups. Baseline plasma glucose or insulin concentrations and glucose area under the curve (AUC) were unaffected by diet. Insulin AUC values for obese and lean cats fed 3-PUFAs did not differ, but values were higher in obese cats fed SFAs, compared with values for lean cats fed SFAs and obese cats fed 3-PUFAs. Nineteen cats that became glucose intolerant when obese had altered insulin secretion and decreased glucose clearance when lean. Plasma cholesterol, triglyceride, and nonesterified fatty acid concentrations were unaffected by diet. Ad libitum intake of either diet resulted in an increase in both intra- and extramyocellular lipid. Obese cats fed SFAs had higher glycosylated hemoglobin concentration than obese cats fed 3-PUFAs.

Conclusions and Clinical Relevance—In obese cats, a diet high in 3-PUFAs appeared to improve long-term glucose control and decrease plasma insulin concentration. Obesity resulted in intra- and extramyocellular lipid accumulations (regardless of diet) that likely modulate insulin sensitivity. (Am J Vet Res2004;65:1090–1099)
Evaluation of three-dimensional ultrasonography of the bovine mammary gland
Authors: Franz Sonja , Hofmann-Parisot Margarete M. , Baumgartner Walter
Published: December 2005

Objective—To evaluate 3-dimensional (3-D) ultrasonography
of the bovine mammary gland, particularly
of the teat.

Animals—6 lactating cows.

Procedures—Clinical and ultrasonographic examinations
of mammary glands of each cow were performed.
Teats were removed from a slaughtered cow
and examined via ultrasonography. All scans were
performed by use of a sensorless standard transducer
(8.5 to 10 MHz linear array). The 2-dimensional data
acquired were downloaded to an off-line system, and
software was used to digitize each image and produce
a 3-D block of digitized information. The selected
anatomic area was displayed as a 3-D volume
cube.

Results—Good-quality, 3-D views of the entire mammary
gland were acquired by obtaining sections
through the glandular parenchyma, gland cistern, teat
cistern, and teat canal.

Conclusions and Clinical Relevance—3-D ultrasonography
allows perspective images of the mammary
gland to be obtained. Many scanners routinely
used in veterinary practice have the resolution
required to produce satisfactory images, and the cost
of refitting a standard ultrasonographic unit with 3-D
software is affordable; however, the cost of a volume
transducer with a positioning system and mechanical
sweep strategy may be prohibitive. Three-dimensional
ultrasonography is a new imaging technique that
has promising applications in many fields of veterinary
medicine. (Am J Vet Res 2004;65:1159–1163)
Comparison of results for serologic testing and a polymerase chain reaction assay to determine the prevalence of stray dogs in eastern Tennessee seropositive to Ehrlichia canis
Authors: Seaman Rebecca L. , Kania Stephen A. , Hegarty Barbara C. , Legendre Alfred M. , Breitschwerdt Edward B.
Published: December 2005

Objective—To determine the prevalence of stray dogs in eastern Tennessee seropositive toEhrlichia canisand examine the correlation between results for an ELISA, indirect immunofluorescent antibody (IFA) test, and polymerase chain reaction (PCR) assay.

Sample Population—Blood samples obtained from 90 adult dogs admitted to an animal shelter in eastern Tennessee.

Procedure—Serum samples were analyzed for antibodies againstE canisby use of a commercially available ELISA kit, 2 IFA tests, and a PCR assay; testing was performed at the University of Tennessee (TN) and North Carolina State University (NCSU). The PCR amplification was performed by use of DNA extracted from EDTA-anticoagulated blood and primers designed to amplify DNA ofEhrlichiaspp.

Results—Antibodies againstE caniswere detected in only 1 dog by use of the ELISA. By IFA testing at TN, 10 of 90 (11%) dogs were seroreactive againstE canisantigens, all of which had medium to high titers toE canis. Only 5 of the 10 TN seroreactors were also reactive againstE canisantigens in IFA tests conducted at NCSU, and all 5 had low to medium titers. The DNA ofEhrlichiaspp was not amplified in any blood samples by use of PCR assays conducted at the TN or NCSU.

Conclusions and Clinical Relevance—The discordant ELISA, IFA, and PCR results obtained in this study were unexpected and may have been related to exposure of dogs to anEhrlichiaspecies other thanE canis, such asE ewingii. (Am J Vet Res2004;65:1200–1203)
Role of the tendons of the biceps brachii and infraspinatus muscles and the medial glenohumeral ligament in the maintenance of passive shoulder joint stability in dogs
Authors: Sidaway Brian K. , McLaughlin Ron M. , Elder Steven H. , Boyle Carolyn R. , Silverman Edward B.
Published: December 2005

Objective—To objectively evaluate the effect of transecting the tendon of the biceps brachii muscle (BBT), tendon of the infraspinatus muscle (IFS), or medial glenohumeral ligament (MGHL) on shoulder joint stability in canine cadavers.

Sample Population—81 forelimbs from mature dogs.

Procedure—Cadaver forelimbs were placed in a testing frame and axially preloaded with 4 kg of weight. Shoulder joint stability was tested in neutral joint position, flexion, and extension before and after transection of the BBT (n = 37), IFS (37), or MGHL (7). Humeral translation relative to the glenoid was induced by applying a 3-kg load in each of 3 directions (cranial, lateral, and medial) and quantitatively measured by use of an electromagnetic motion tracking system. Peak translational data were compared in each joint position before and after transection of the BBT, IFS, or MGHL.

Results—When tested in neutral position, the cranial, lateral, and medial translation of the humerus was significantly increased after BBT transection. In the flexed position, translation of the humerus in the cranial and lateral directions was significantly increased after BBT transection. In the extended position, the medial translation of the humerus was significantly increased after BBT transection. Complete medial luxation of all humeral heads occurred following transection of the MGHL.

Conclusions and Clinical Relevance—The BBT contributes to passive shoulder joint stability in dogs, particularly in the neutral and flexed positions. It also provides medial stability during shoulder joint extension. Complete luxation of the joint occurs when the MGHL is transected. (Am J Vet Res2004;65:1216–1222)
Effects of exchange of dietary medium chain triglycerides for long-chain triglycerides on serum biochemical variables and subjectively assessed well-being of dogs with exocrine pancreatic insufficiency
Authors: Rutz Gabriele M. , Steiner Jörg M. , Bauer John E. , Williams David A.
Published: December 2005

Objective—To test the hypothesis that exchange of medium-chain triglycerides (MCTs) for long-chain triglycerides (LCTs) in the diet of dogs with well-managed exocrine pancreatic insufficiency (EPI) changes serum biochemical variables and to subjectively assess the well-being of dogs with EPI in response to experimental diets.

Animals—21 dogs with EPI and 6 healthy control dogs.

Procedure—The effects of 3 diets containing 0%, 16%, or 35% of the total fat content as MCTs were examined in a randomized controlled double-blind crossover trial. The 3 diets were fed for 12 weeks each. Dietary effects were evaluated by both subjective and objective variables.

Results—Analysis of subjective data revealed no significant difference in appetite, attitude, drinking behavior, volume of feces, defecation frequency, color of feces, consistency of feces, flatulence, or borborygmus among dogs fed the 3 experimental diets. A high MCT content in the diet was associated with significantly higher serum vitamin E, cholesterol, triglyceride, retinyl stearate, retinyl palmitate, and total vitamin A concentrations in dogs with EPI and significantly higher serum vitamin E concentrations in control dogs, compared with low MCT content. High MCT content in the diet was also associated with significantly lower concentrations of serum linoleic acid (C18:2[n-6]) in dogs with EPI and in control dogs, compared with low MCT content.

Conclusions and Clinical Relevance—A high MCT content in the diet leads to increases in serum concentrations of cholesterol and certain fat-soluble vitamins. However, no effect was found on the subjective well-being of the dogs as evaluated by their owners. (Am J Vet Res2004;65:1293–1302)
Effects of injury to the suspensory apparatus, exercise, and horseshoe characteristics on the risk of lateral condylar fracture and suspensory apparatus failure in forelimbs of Thoroughbred racehorses
Authors: Hill Ashley E. , Gardner Ian A. , Carpenter Tim E. , Stover Susan M.
Published: December 2005

Objective—To assess concurrently the effects of moderate ligamentous suspensory apparatus injury (MLSAI), racing-speed exercise, and horseshoe characteristics on risk of catastrophic suspensory apparatus failure (SAF) or metacarpal condylar fracture (CDY) in forelimbs of racehorses.

Sample population—Cadavers of 301 Thoroughbred racehorses (108 with SAF, 33 with CDY, and 160 control horses).

Procedure—A cross-sectional epidemiologic study was used to describe distributions and relationships between MLSAI, exercise, and horseshoe variables. Logistic regression was used to assess potential risk factors for developing SAF and CDY.

Results—Exercise variables were more highly associated with age than height of a steel bar affixed to the ground surface of the front of a horseshoe (ie, toe grab) or sex. Marginal associations were detected between MLSAI and age and height of toe grab. Higher risk for developing SAF was associated with MLSAI, use of a pad on a horseshoe, longer interval since last period of ≥ 60 days without a race or timed workout (ie, layup), 2 to 5 career races, and higher intensity of recent exercise. Higher risk for developing CDY was associated with MLSAI, male horses, age between 2 and 5 years, higher intensity of recent exercise, and longer interval since layup.

Conclusions and Clinical Relevance—Recognition of MLSAI and rehabilitation of affected horses should reduce incidence of SAF and CDY. Horses in long-term continuous training with recent high-intensity exercise are at greater risk for injury. Use of pads in horseshoes was associated with SAF, although the relationship may not be causal. (Am J Vet Res2004;65:1508–1517).
Microbiologic findings in feedlot cattle with acute interstitial pneumonia
Authors: Woolums Amelia R. , Mason Gary L. , Hawkins Larry L. , Brown Corrie C. , Williams Shamita M. , Gould Jared A. , Fox Jocelyn J. , Sturgeon Scott D. , Anderson Jenny L. , Duggan Florence E. , Sanchez Susan , Barrett Paula B. , Chitwood Sharon W.
Published: December 2005

Objective—To test the hypothesis that feedlot cattle with acute interstitial pneumonia (AIP) have bacterial infection of the lung or liver and concurrent bovine respiratory syncytial virus (BRSV) infection significantly more often than pen mates without AIP.

Animals—39 feedlot cattle with signs consistent with AIP and no history of treatment with antimicrobials and 32 healthy control cattle from the same pens.

Procedure—Lung and liver specimens were obtained postmortem for bacterial or mycoplasmal culture and histologic examination; lung tissue was assessed for BRSV infection immunohistochemically.

Results—Among affected cattle, 26 had AIP confirmed histologically. Lung tissue from 11 cattle with AIP yielded microbial respiratory tract pathogens on culture; tissues from control animals yielded no microbial growth. In 4 cattle with AIP and 2 control animals, liver abscesses were detected; bacteria were isolated from abscessed tissue in 3 and 1 of those animals, respectively. Immunohistochemically, 9 cattle with AIP and no control animals were BRSV-positive. Histologically, 9 AIP-affected cattle had only acute alveolar damage with exudation, and the other 17 had acute exudation with type II pneumocyte hyperplasia. No lesions of AIP were detected in control animals. Only 4 AIP-affected cattle had bacterial infection of the lung with concurrent BRSV infection.

Conclusions and Clinical Relevance—Results indicated that microbial respiratory tract pathogens are more common in cattle with AIP than in healthy pen mates. Control of bacterial pneumonia late in the feeding period may reduce the incidence of AIP at feedlots where AIP is a problem. (Am J Vet Res2004;65:1525–1532)
Pharmacokinetic-pharmacodynamic relationships and dose response to meloxicam in horses with induced arthritis in the right carpal joint
Authors: Toutain Pierre-Louis , Cester Corinne C.
Published: December 2005

Objective—To determine pharmacokinetic-pharmacodynamic
(PK-PD) relationships and dose effects for
meloxicam in horses and to propose a suitable
dosage for use in clinical studies.

Animals—6 adult horses.

Procedure—The study was conducted by use of a
randomized, Latin-square design. Arthritis was
induced in the right carpal joint of each horse by
administration of Freund's complete adjuvant. Various
dosages of meloxicam (0, 0.25, 0.5, 1.0, and
2.0 mg/kg, IV) were then administered. Validated endpoints
including stride length and overall clinical lameness
score (scale of 0 to 20) were used to assess the
effect of meloxicam. The dose-effect relationship was
quantified by use of a maximum possible effect
(Emax) model.

Results—For stride length (expressed as a relative
percentage increase from control values), the median
effective dose (ED50) was 0.120 mg/kg for an
Emax of 11.15%. For clinical lameness score
(expressed as an absolute increase from the control
value), the ED50 was 0.265 mg/kg for an Emax of
9.16 units. The PK-PD analysis allowed calculation of
a median effective concentration of 130 ng/mL for
stride length and 195 ng/mL for lameness score. Use
of the Emax model predicted a maximal possible
increase in effect of 19.5% for stride length and
13.91 units for lameness score. For stride length and
lameness score, the Hill coefficient (slope) was
extremely high, which suggested a steep dose-effect
relationship.

Conclusions and Clinical Relevance—Results of
this study suggest that meloxicam is a potent anti-inflammatory
drug in horses. A dosage of 0.6 mg/kg/d
would be appropriate for use in a clinical study. (Am J Vet Res 2004;65:1533–1541)
Comparison of hepatic in vitro metabolism of the pyrrolizidine alkaloid senecionine in sheep and cattle
Authors: Duringer Jennifer M. , Buhler Donald R. , Craig A. Morrie
Published: December 2005

Objective—To compare hepatic metabolism of pyrrolizidine alkaloids (PAs) between sheep and cattle and elucidate the protective mechanism of sheep.

Sample Population—Liver microsomes and cytosol from 8 sheep and 8 cattle.

Procedure—The PA senecionine, senecionineN-oxide (nontoxic metabolite) and 6,7-dihydro-7-hydroxy- 1-hydroxymethyl-5H-pyrrolizine (DHP; toxic metabolite) were measured in microsomal incubations. The kcat(turnover number) was determined for DHP and N-oxide formation. Chemical and immunochemical inhibitors were used to assess the role of cytochrome P450s, flavin-containing monooxygenases (FMOs), and carboxylesterases in senecionine metabolism. The CYP3A, CYP2B, and FMO concentrations and activities were determined, in addition to the role of glutathione (GSH) in senecionine metabolism.

Results—DHP concentration did not differ between species. Sheep formed moreN-oxide, had higherN-oxide kcat, and metabolized senecionine faster than cattle. The P450 concentrations and isoforms had a large influence on DHP formation, whereas FMOs had a large influence onN-oxide formation. In cattle, CYP3A played a larger role in DHP formation than in sheep. FMO activity was greater in sheep than in cattle. Addition of GSH to in vitro microsomal incubations decreased DHP formation; addition of cytosol decreasedN-oxide formation.

Conclusions and Clinical Relevance—Hepatic metabolism differences alone do not account for the variation in susceptibility seen between these species. Rather, increased ruminal metabolism in sheep appears to be an important protective mechanism, with hepatic enzymes providing a secondary means to degrade any PAs that are absorbed from the rumen. (Am J Vet Res2004;65:1563–1572)
Assessment of lipid peroxidation and serum vitamin E concentration in dogs with immune-mediated hemolytic anemia
Authors: Pesillo S. Anna , Freeman Lisa M. , Rush John E.
Published: December 2005

Objective—To determine plasma malondialdehyde (MDA) and serum vitamin E concentrations in dogs with immune-mediated hemolytic anemia (IMHA) and healthy control dogs.

Sample Population—Serum and plasma samples from 36 dogs with IMHA and 40 healthy control dogs.

Procedure—Blood samples were collected from all study dogs. Plasma MDA concentrations were measured by use of a commercial colorimetric assay, and serum vitamin E concentrations (α-, γ-, and δ-tocopherol concentrations) were measured via high-performance liquid chromatography.

Results—Plasma MDA concentrations were significantly higher in the dogs with IMHA than in the control dogs. Compared with control dogs, serum α-, γ-, and δ-tocopherol concentrations were significantly lower in the IMHA-affected dogs.

Conclusions and Clinical Relevance—Results indicated a state of oxidative stress and reduced antioxidant reserve in dogs with IMHA; this finding provides support for further investigation of the potential benefits of antioxidant treatment in dogs with this disease. (Am J Vet Res2004;65:1621–1624)
Serum concentrations of cortisol, sex hormones of adrenal origin, and adrenocortical steroid intermediates in healthy dogs following stimulation with two doses of cosyntropin
Authors: Frank Linda A. , Davis Jacqueline A. , Oliver Jack W.
Published: December 2005

Objective—To compare the effects of 2 doses of cosyntropin (5 µg/kg vs 250 µg, IV) on serum concentrations of cortisol, sex hormones of adrenal origin, and adrenocortical steroid intermediates and determine the optimal sample collection time after adrenal stimulation with cosyntropin.

Animals—10 healthy, privately owned, neutered dogs.

Procedure—Dogs were randomly assigned to initially receive cosyntropin at 5 µg/kg or as a total dose of 250 µg, IV. Dogs received the alternate dose 1 to 2 weeks later. Serum was obtained from blood samples collected before (0 minutes) and 30, 60, 90, and 120 minutes after cosyntropin administration.

Results—Maximum stimulation of cortisol, androstenedione, progesterone, and 17-hydroxyprogesterone production was achieved at 60 minutes following IV administration of cosyntropin at 5 µg/kg or as a total dose of 250 µg. Serum estradiol concentration did not increase in response to either cosyntropin dose. For all hormones, no significant difference in serum hormone concentrations was found among sample collection times of 0, 30, 60, and 90 minutes when comparing the 2 doses of cosyntropin.

Conclusions and Clinical Relevance—Cosyntropin, when administered at 5 µg/kg, IV, effectively stimulated maximum production of cortisol, sex hormones of adrenal origin, and adrenocortical steroid intermediates at 1 hour after administration. (Am J Vet Res2004;65:1631–1633)
Observer variation in visual assessment of forelimb horseshoe characteristics on Thoroughbred racehorses
Authors: Gross Diane K. , Stover Susan M. , Hill Ashley E. , Gardner Ian A.
Published: December 2005

Objective—To assess the accuracy and reliability of a visual method of evaluating horseshoe characteristics.

Animals—1,199 Thoroughbred racehorses.

Procedure—Characteristics of 1 forelimb horseshoe were visually assessed on horses immediately prior to racing by 5 field observers at 5 major racetracks in California. Characteristics evaluated included horseshoe type; toe grab height; and the presence of a rim, pad, and heel traction devices. Sensitivity and specificity for observer assessment of horseshoe characteristics were calculated by comparing observer assessments to a postmortem laboratory standard for horses that died within 48 hours of a race. Intraobserver agreement was assessed in a subset of horses by comparing horseshoe observations made before and after the horse's race. Interobserver agreement was evaluated by comparing horseshoe assessment among observers who examined the same subset of horses prior to racing on select days.

Results—The sensitivity and specificity of this visual method of evaluating horseshoe characteristics were good and ranged from 0.75 to 1 and 0.67 to 1, respectively. Agreement beyond chance (weighted kappa values) between observers and the laboratory standard for toe grab height was fair (0.60 to 0.62). Intraobserver and interobserver agreements (kappa values) were high (0.86 to 0.99 and 0.71 to 1, respectively).

Conclusions and Clinical Relevance—Visual observation of horseshoes can be a feasible and reproducible method for assessing horseshoe characteristics prospectively in a large cohort of horses under racing conditions. (Am J Vet Res2004;65:1674–1679)
Expression of the cyclooxygenase isoforms in the prodromal stage of black walnut-induced laminitis in horses
Authors: Waguespack R. Wayne , Cochran Anne , Belknap James K.
Published: December 2005

Objective—To compare the levels of mRNA expression of cycooxygenase (COX)-1 and COX-2 in the digital laminae of normal horses and horses in the developmental stages of laminitis experimentally induced by administration of black walnut extract (BWE).

Sample Population—Samples of mRNA extracted from the digital laminae of 5 control horses and 5 horses at the onset of leukopenia after administration of BWE.

Procedure—Specimens of laminae were collected from anesthetized horses prior to euthanasia. Expression of COX-1 and COX-2 mRNA in laminae of control and affected horses was evaluated via realtime quantitative polymerase chain reaction techniques.

Results—Expression of COX-2 mRNA was significantly increased in the BWE-treated group, compared with that in control horses. In contrast to COX-2 regulation, COX-1 mRNA expression was not significantly different between groups. Interestingly, despite consistent clinical signs such as leukopenia in all BWE-treated horses, distinct differences in COX-2 mRNA expression were detected among those 5 horses (compared with values for control horses, the increase in COX-2 mRNA expression ranged from no increase to a 30-fold increase).

Conclusions and Clinical Relevance—Results indicated that there was a significant upregulation of COX-2 mRNA expression during the developmental stages of laminitis, with no significant change in expression of the COX-1 isoform. These data appear to provide support for aggressive use of nonsteroidal anti-inflammatory drugs in horses at risk for laminitis; further investigation into the clinical value of selective COX-2 inhibitors for treatment of laminitis in horses appears to be warranted. (Am J Vet Res2004;65:1724–1729)
Comparison of the use of regulatory assays and high-performance liquid chromatography for detection of residues of ceftiofur sodium metabolites in tissue specimens of culled dairy cattle
Authors: Payne Michael A. , Wetzlich Scott E. , Robb Edward J. , Brown Scott A. , Gardner Ian A. , Cullor James S. , Craigmill Arthur L.
Published: December 2005

Objective—To compare the results of regulatory screening and confirmation assays with those of highperformance liquid chromatography (HPLC) in the detection of ceftiofur metabolites in the tissues of culled dairy cattle.

Animals—17 lactating Holstein dairy cows.

Procedure—Daily IM injections of ceftiofur sodium were administered at a dose of 2.2 mg of ceftiofur equivalents/kg (n = 6) or 1.0 mg of ceftiofur equivalents/kg (10) for 5 days. Following withdrawal times of 12 hours (high-dose ceftiofur) and either 5 or 10 days (low-dose ceftiofur), cows were slaughtered and liver, kidney, and diaphragmatic muscle specimens were harvested and analyzed by HPLC and standard regulatory methods that included the following assays: the swab test on premises, the fast antimicrobial screen test, the calf antibiotic and sulfa test, and the 7-plate bioassay confirmation test.

Results—In all tissue specimens, residues of ceftiofur and desfuroylceftiofur-related metabolites, as measured by HPLC, were less than regulatory tolerance, as defined by the FDA. False-positive screening assay results were more likely for tissue specimens that had been frozen for shipment to a federal laboratory, compared with fresh tissue specimens that were assayed at the slaughter establishment (23% vs 3% false-positive results, respectively).

Conclusions and Clinical Relevance—The observation that fresh tissues had negative results on screening assays, whereas subsets of the same tissue specimens had false-positive results on screening assays following freezing, suggests that freezing and thawing interferes with microbial inhibition-based regulatory screening assays. (Am J Vet Res2004;65:1730–1733)
Molecular epidemiologic features of Corynebacterium pseudotuberculosis isolated from horses
Authors: Foley Janet E. , Spier Sharon J. , Mihalyi Judy , Drazenovich Niki , Leutenegger Christian M.
Published: December 2005

Objective—To characterize isolates ofCorynebacterium pseudotuberculosisfrom horses, cattle, and sheep in Colorado, Kentucky, Utah, and California in samples collected during perceived epidemics of infection (increased numbers of cases identified) in 2002 and 2003, and determine how closely isolates were related and their possible source.

Sample Population—54 isolates ofC pseudotuberculosisfrom 49 horses, 4 cattle, and 1 sheep.

Procedures—Random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) assay, PCR assay for the gene encoding the phospholipase D (PLD) toxin, biochemical analyses, and tests for susceptibility to 17 antimicrobial drugs were performed.

Results—All isolates reduced nitrate to nitrite, most yielded positive results for the PLD toxin gene, and all were susceptible to antimicrobial drugs. Ten genetic types were detected by use of RAPD PCR assay; types III to X were isolated from horses, cattle, or both in 1 or more states. Types III and IX were isolated from both horses and cattle. Types VII and VIII were isolated in only 1 state, but the number of isolates in these groups was small. In contrast, all other types were isolated in 2 or more states. All isolates from Utah were type III, but the other 3 states had isolates from more than 1 type.

Conclusions and Clinical Relevance—These data are consistent with a clonally expanding epidemic of infection in Utah and an increase in number of infections caused by multiple strains ofC pseudotuberculosisnot derived from a single source in the other states. The increase in number of infections could be the result of reporting bias, environmental factors facilitating infection, or host factors such as greater herd susceptibility. (Am J Vet Res2004;65:1734–1737)
Effects of feeding meals with various soluble-carbohydrate content on muscle glycogen synthesis after exercise in horses
Authors: Lacombe Véronique A. , Hinchcliff Kenneth W. , Kohn Catherine W. , Devor Stephen T. , Taylor Lynn E.
Published: December 2005

Objectives—To determine effects of feeding diets with various soluble-carbohydrate (CHO) content on rates of muscle glycogen synthesis after exercise in horses.

Animals—7 fit horses.

Procedures—In a 3-way crossover study, horses received each of 3 isocaloric diets (a high soluble CHO [HC] diet, a low soluble CHO [LC] diet, or a mixed soluble CHO [MC] diet). For each diet, horses were subjected to glycogen-depleting exercise, followed by feeding of the HC, LC, or MC diet at 8-hour intervals for 72 hours.

Results—Feeding the HC diet resulted in a significantly higher glycemic response for 72 hours and significantly greater muscle glycogen concentration at 48 and 72 hours after exercise, compared with results after feeding the MC and LC diets. Muscle glycogen concentrations similar to baseline concentrations were detected in samples obtained 72 hours after exercise in horses when fed the HC diet. Rate of glycogen synthesis was significantly higher when horses were fed the HC diet, compared with values when horses were fed the MC and LC diets. Glycogen synthase activity was inversely related to glycogen content. Protein content of glucose transporter-4 was the lowest at 72 hours after exercise when horses were fed the HC diet.

Conclusions and Clinical Relevance—Muscle glycogen synthesis was slower after glycogen-depleting exercise in horses, compared with synthesis in humans. Feeding HC meals after strenuous exercise hastened replenishment of muscle glycogen content, compared with results for feeding of LC and MC diets, by increasing availability of blood glucose to skeletal muscles. (Am J Vet Res2004;65:916–923)
Variation in free jumping technique within and among horses with little experience in show jumping
Authors: Santamaría Susana , Bobbert Maarten F. , Back Willem , Barneveld Ab , van Weeren P. René
Published: December 2005

Objective—To quantify variation in the jumping technique within and among young horses with little jumping experience, establish relationships between kinetic and kinematic variables, and identify a limited set of variables characteristic for detecting differences in jumping performance among horses.

Animals—Fifteen 4-year-old Dutch Warmblood horses.

Procedure—The horses were raised under standardized conditions and trained in accordance with a fixed protocol for a short period. Subsequently, horses were analyzed kinematically during free jumping over a fence with a height of 1.05 m.

Results—Within-horse variation in all variables that quantified jumping technique was smaller than variation among horses. However, some horses had less variation than others. Height of the center of gravity (CG) at the apex of the jump ranged from 1.80 to 2.01 m among horses; this variation could be explained by the variation in vertical velocity of the CG at takeoff (r, 0.78). Horses that had higher vertical velocity at takeoff left the ground and landed again farther from the fence, had shorter push-off phases for the forelimbs and hind limbs, and generated greater vertical acceleration of the CG primarily during the hind limb pushoff. However, all horses cleared the fence successfully, independent of jumping technique.

Conclusions and Clinical Relevance—Each horse had its own jumping technique. Differences among techniques were characterized by variations in the vertical velocity of the CG at takeoff. It must be determined whether jumping performance later in life can be predicted from observing free jumps of young horses. (Am J Vet Res2004;65:938–944)
Evaluation of consistency of jumping technique in horses between the ages of 6 months and 4 years
Authors: Santamaría Susana , Bobbert Maarten F. , Back Willem , Barneveld Ab , van Weeren P. René
Published: December 2005

Objective—To determine whether differences in jumping technique among horses are consistent at various ages.

Animals—12 Dutch Warmblood horses.

Procedure—Kinematics were recorded during free jumps of horses when they were 6 months old (ie, no jumping experience) and 4 years old (ie, the horses had started their training period to become show jumpers). Mean ± SD height of the horses was 1.40 ± 0.04 m at 6 months of age and 1.70 ± 0.05 m at 4 years of age.

Results—Strong correlations were found between values from 6-month-old foals and 4-year-old horses for variables such as peak vertical acceleration generated by the hind limbs (r, 0.91), peak rate of change of effective energy generated by the hind limbs (r, 0.71), vertical velocity at takeoff (r, 0.65), vertical displacement of the center of gravity during the airborne phase (r, 0.81), and duration of the airborne phase (r, 0.70).

Conclusions and Clinical Relevance—Although there are substantial anatomic and behavioral changes during the growing period, certain characteristics of jumping technique observed in naïve 4-year-olds are already detectable when those horses are foals. (Am J Vet Res2004;65:945–950)
Effect of laser shock peening on fatigue life and surface characteristics of stainless steel cortical bone screws
Authors: O'Sullivan Christopher B. , Bertone Alicia L. , Litsky Alan S. , Robertson James T.
Published: December 2005

Objective—To investigate the effect of laser shock
peening on the fatigue life and surface characteristics
of 3.5-mm-diameter cortical bone screws.

Sample Population—32 stainless steel, 3.5-mm-diameter
cortical bone screws.

Procedure—Screws were randomly assigned to an
untreated control group or 2 power-density treatment
groups, 6 gigawatts (GW)/cm2 and 8.5 GW/cm2, for laser
shock peening. Number of cycles to failure and findings
on scanning electron microscopy-assisted morphometric
evaluation, including the mode of failure, surface
debris, surface damage, and thread deformation, were
compared between control and treated screws.

Results—The 6 GW/cm2 treated screws had a significant
(11%) improvement in fatigue life, compared
with untreated control screws. The 8.5 GW/cm2 treated
screws had a significant (20%) decrease in fatigue
life, compared with control screws. A mild but significant
increase in thread deformation was evident in all
treated screws, compared with control screws. The
8.5 GW/cm2 treated screws had significantly more
surface irregularities (elevations and pits), compared
with control or 6 GW/cm2 treated screws.

Conclusions and Clinical Relevance—A modest positive
increase in fatigue strength was produced by this
design of laser shock peening on the midshaft of cortical
bone screws. High laser shock peening power densities
were detrimental, decreasing screw fatigue strength
probably resulting from structural damage. Greater
fatigue life of cortical bone screws can be generated
with laser shock peening and could reduce screw breakage
as a cause of implant failure; however, future studies
will be necessary to address biocompatibility, alternative
cleaning techniques, alterations in screw strength
and pullout characteristics, and effects on susceptibility
to corrosion. ( Am J Vet Res 2004;65:972–976)
Stability, antigenicity, and aggregation of Moraxella bovis cytolysin after purification and storage
Authors: George Lisle W. , Angelos John A. , Ruehl William W.
Published: December 2005

Objectives—To compare stability, antigenicity, and aggregation characteristics ofMoraxella boviscytolysins among isolates from geographically diverse areas.

Study Population—8 isolates ofM bovis.

Procedure—Filter-sterilized broth culture supernatants ofM boviswere concentrated, diafiltered, and chromatographed. The endotoxin and cytolysin activities in samples were measured. Chromatographed cytolysins ofM boviswere examined by immunoblotting. Hemolytic and leukotoxic activities were measured from samples collected at each step of purification and before and after storage. Hemolysis was measured directly by use of washed bovine erythrocyte targets. Leukotoxicity was measured by use of a51Cr release assay.

Results—Cytolysin was retained by a filter with 100-kd nominal molecular weight limit. Hemolytic activity, leukotoxic activity, and endotoxin were eluted together in void volume of a gel-filtration column (molecular mass exclusion limit = 4 × 107d). Gel-column chromatographed diafiltered retentate had the greatest specific cytolytic activity and the highest endotoxinto- protein ratio. Frozen diafiltered retentate(–80°C, 4 months) was cytolytic after thawing. Immunoblots of gel-column chromatographed cytolysin contained 4 proteins with molecular masses between 90 and 68 kd. Fractions with high lytic activities also had additional protein bands with molecular masses of 98 and 63 kd. Immunoblots of gel-column chromatographed diafiltered retentate revealed proteins with molecular masses between 90 and 68 kd.

Conclusions and Clinical Relevance—DiafilteredM boviscytolysin is aggregated with endotoxin. Antigenicity and cytolytic activities in diafiltered retentate are conserved amongM bovisisolates. Diafiltration could be useful for bulk semipurification ofM boviscytolysin. Cytolysin-enriched vaccines ofM boviscould be contaminated by endotoxin. (Am J Vet Res2004;65:977–983)
Effects of dietary antioxidant supplementation before and after oral acetaminophen challenge in cats
Authors: Hill Ana S. , Rogers Quinton R. , O'Neill Sharron L. , Christopher Mary M.
Published: December 2005

Objective—To determine effects of lipoic acid, vitamin E, and cysteine before and after oxidant challenge in cats.

Animals—24 sexually intact adult cats.

Procedure—Cats were allocated into 4 equal groups. For 25 weeks, group A was fed a control dry diet and groups B, C, and D received this diet supplemented with vitamin E (2,200 U/kg [dry matter basis {DMB}]) plus cysteine (9.5 g/kg [DMB]), lipoate (150 mg/kg [DMB]), or all 3 antioxidants together, respectively. Weights were measured every 3 days and venous blood obtained every 5 weeks for CBC; serum biochemical analyses; lymphocyte blastogenesis; thiobarbituric acid reactive substances concentration; and concentrations of plasma protein carbonyl, 8-OH dguanosine, blood glutathione, plasma amino acid, lipoate, and dihydrolipoate. At 15 weeks, all cats received acetaminophen (9 mg/kg, PO, once), clinical effects were observed, and methemoglobin concentrations were measured.

Results—Lymphocyte blastogenesis increased transiently in group C and D cats. After acetaminophen administration, all groups had transient increases in methemoglobin within 4 hours and mild, brief facial edema; group C had decreased glutathione concentration and increased 8-OH d-guanosine concentration versus controls; and protein carbonyl concentration increased least for group B. Plasma lipoate and dihydrolipoate concentrations peaked by week 10 for groups C and D.

Conclusions and Clinical Relevance—Lipoate, vitamin E, and cysteine did not have synergistic effects. Lipoate supplementation (150 mg/kg [DMB]) did not act as an antioxidant but appeared to enhance oxidant effects of acetaminophen. Vitamin E plus cysteine had protective effects. (Am J Vet Res2005;66:196–204)