bluuebunny/crossref_metadata_2025 huggingface dataset:
Systemic and pituitary pars intermedia antioxidant capacity associated with pars intermedia oxidative stress and dysfunction in horses
Authors: McFarlane Dianne , Cribb Alastair E.
Published: December 2005

Objective—To determine whether a deficiency in
systemic or local (pars intermedia) antioxidant capacity
is associated with pituitary pars intermedia oxidative
stress and pituitary pars intermedia dysfunction
(PPID) in horses.

Sample Population—Blood samples from 20 horses
with PPID and 20 healthy client-owned horses,
archived paraffin-embedded adrenal gland and substantia
nigra tissues from 20 horses, and pituitary
gland tissue from 16 horses.

Procedures—Total glutathione, superoxide dismutase,
and glutathione peroxidase activities were
determined in RBCs. Accumulation of a systemic
marker of oxidative stress (3-nitrotyrosine) was
assessed in plasma and formalin-fixed, paraffinembedded
adrenal gland and substantia nigra tissues.
Local antioxidants (total and manganese
superoxide dismutase, glutathione peroxidase, and
total glutathione) were measured in pars intermedia
tissues.

Results—No significant differences existed in systemic
antioxidant enzyme activity or accumulation of
3-nitrotyrosine between horses with PPID and control
horses. In pituitary gland tissues, glutathione peroxidase
activity was increased in horses with oxidative
stress, whereas total glutathione concentration and
superoxide dismutase activity remained unchanged.
There was an age-associated decrease in manganese
superoxide dismutase activity in the pars intermedia.

Conclusions and Clinical Relevance—There was
no evidence of systemic accumulation of oxidative
stress markers or deficiencies in antioxidant capacity
in horses with PPID, suggesting that these are
unlikely to be major predisposing factors in the
development of PPID. Manganese superoxide dismutase
activity in the pars intermedia decreased
significantly with increasing age. Role of an ageassociated
decrease in antioxidant capacity for the
pars intermedia in the development of PPID in horses
warrants further investigation. (Am J Vet Res
2005;66:2065–2072)
Effect of marbofloxacin on cardiovascular variables in healthy isoflurane-anesthetized dogs
Authors: Chanoit Guillaume P. , Schneider Marc , Woehrlé Frédérique , Lefebvre Hervé P.
Published: December 2005

Objective—To study the hemodynamic effects of marbofloxacin (MBF) in isoflurane-anesthetized dogs.

Animals—6 healthy 8-month-old Beagles.

Procedure—Anesthesia was induced with sodium thiopental and maintained with isoflurane. Cardiovascular variables were monitored throughout anesthesia. Marbofloxacin was administered by an IV bolus at 2 mg/kg, followed 10 minutes later by an infusion at a rate of 40 mg/kg/h for 30 minutes (total dose, 20 mg/kg). Plasma MBF concentrations were measured by high-performance liquid chromatography.

Results—The mean peak concentration during MBF infusion was 34.2 ± 6.4 µg/mL. The IV administration of the MBF bolus did not alter any cardiovascular variable in isoflurane-anesthetized dogs. Significant changes were found during infusion when a cumulative dose of 12 mg/kg had been given. The maximal decreases observed at the end of the infusion were 16% in heart rate, 26% in systolic left ventricular pressure, 33% in systolic aortic pressure, 38% in diastolic aortic pressure, 29% in cardiac output, and 12% in QT interval. All dogs recovered rapidly from anesthesia at the end of the experiment.

Conclusions and Clinical Relevance—MBF may safely be used at 2 mg/kg IV in isoflurane-anesthetized dogs, and significant adverse cardiovascular effects are found only when 6 to 8 times the recommended dose is given. (Am J Vet Res2005;66:2090–2094)
Evaluation of skin sensitivity after shock wave treatment in horses
Authors: Waldern Nina M. , Weishaupt Michael A. , Imboden Isabel , Wiestner Thomas , Lischer Christoph J.
Published: December 2005

Objective—To evaluate the effects of shock wave treatment on cutaneous nerve function, compared with the effects of local nerve block and sedation.

Animals—18 clinically sound Swiss Warmbloods.

Procedure—Horses were randomly allocated to 3 groups and received different amounts and types of shock waves (extracorporeal shock wave treatment [ESWT] or radial pressure wave treatment [RPWT]). Horses were sedated with xylazine and levomethadone. Shock waves were applied to the lateral palmar digital nerve at the level of the proximal sesamoid bones on 1 forelimb. Skin sensitivity was evaluated by means of an electrical stimulus at the coronary band before and 5 minutes after sedation and at 4, 24, and 48 hours after application of ESWT or RPWT. On the contralateral forelimb, skin sensitivity was tested before and 10 minutes after an abaxial sesamoid nerve block.

Results—No significant changes in skin sensitivity were detected, regardless of the shock wave protocol applied. Mean reaction thresholds after sedation were more than twice the baseline thresholds. After the abaxial sesamoid block, no reaction was recorded in any of the horses.

Conclusions and Clinical Relevance—Application of ESWT or RPWT to the palmar digital nerve had no effect on cutaneous sensation distal to the treated region for at least 2 days after application. The analgesic effect of sedation on reaction to electrical stimuli was distinct but varied among horses. (Am J Vet Res2005;66:2095–2100)
Evaluation of quantified contrast-enhanced color and power Doppler ultrasonography for the assessment of vascularity and perfusion of naturally occurring tumors in dogs
Authors: Schärz Myriam , Ohlerth Stefanie , Achermann Roger , Gardelle Olivier , Roos Malgorzata , Saunders H. Mark , Wergin Melanie , Kaser-Hotz Barbara
Published: December 2005

Objective—To investigate subjective and computerized
methods of evaluation of color Doppler (CD) and
power Doppler (PD) ultrasonographic images
(obtained before and after administration of contrast
medium) for quantitative assessment of vascularity
and perfusion of various naturally occurring tumors in
dogs.

Sample Population—34 tumors in 34 dogs.

Procedure—Tumors in dogs were examined via CD
and PD ultrasonography before and after IV injection
of a microbubble contrast agent (pre- and postcontrast
examinations, respectively). Images were digitized
for subjective assessment of vessel density and
vascular pattern and computer-aided assessment of
parameters of vascularity (fractional area [FA]) and
perfusion (color-weighted FA [CWFA] and mean color
level).

Results—With both analysis methods, more vessels
were identified in precontrast PD ultrasonographic
images than in precontrast CD ultrasonographic
images. Moreover, compared with values for precontrast
PD ultrasonography, FA, CWFA, and mean color
level were higher for postcontrast PD ultrasonography.
In postcontrast images, there was a significant
association between vessel densities determined
through subjective and computerized assessments.
Although sample size was small, vascularity of squamous
cell carcinomas was significantly greater than
that of other tumor types. Ten of the 19 soft tissue
sarcomas had low vessel density with minor contrast
enhancement. With increasing gross tumor volume,
FA and CWFA decreased for all Doppler ultrasonographic
methods.

Conclusions and Clinical Relevance—Higher values
of the ultrasonographic parameters representing vascularity
and perfusion of tumors in dogs were determined
via PD ultrasonography after administration of
contrast medium than via PD or CD ultrasonography
without administration of contrast medium. (Am J Vet Res 2005;66:21–29)
Use of proxies and reference quintiles obtained from minimal model analysis for determination of insulin sensitivity and pancreatic beta-cell responsiveness in horses
Authors: Treiber Kibby H. , Kronfeld David S. , Hess Tanja M. , Boston Ray C. , Harris Pat A.
Published: December 2005

Objective—To develop proxies calculated from basal plasma glucose and insulin concentrations that predict insulin sensitivity (SI; L·min–1·mU–1) and beta-cell responsiveness (ie, acute insulin response to glucose [AIRg]; mU/L·min–1) and to determine reference quintiles for these and minimal model variables.

Animals—1 laminitic pony and 46 healthy horses.

Procedure—Basal plasma glucose (mg/dL) and insulin (mU/L) concentrations were determined from blood samples obtained between 8:00 AM and 9:00 AM. Minimal model results for 46 horses were compared by equivalence testing with proxies for screening SI and pancreatic beta-cell responsiveness in humans and with 2 new proxies for screening in horses (ie, reciprocal of the square root of insulin [RISQI] and modified insulin-to-glucose ratio [MIRG]).

Results—Best predictors of SI and AIRg were RISQI (r= 0.77) and MIRG (r= 0.75) as follows: SI = 7.93(RISQI) – 1.03 and AIRg = 70.1(MIRG) – 13.8, where RISQI equals plasma insulin concentration–0.5and MIRG equals [800 – 0.30(plasma insulin concentration – 50)2]/(plasma glucose concentration – 30). Total predictive powers were 78% and 80% for RISQI and MIRG, respectively. Reference ranges and quintiles for a population of healthy horses were calculated nonparametrically.

Conclusions and Clinical Relevance—Proxies for screening SI and pancreatic beta-cell responsiveness in horses from this study compared favorably with proxies used effectively for humans. Combined use of RISQI and MIRG will enable differentiation between compensated and uncompensated insulin resistance. The sample size of our study allowed for determination of sound reference range values and quintiles for healthy horses. (Am J Vet Res2005;66:2114–2121)
Comparison of the cardiopulmonary effects of anesthesia maintained by continuous infusion of ketamine and propofol with anesthesia maintained by inhalation of sevoflurane in goats undergoing magnetic resonance imaging
Authors: Larenza M. Paula , Bergadano Alessandra , Iff Isabelle , Doherr Marcus G. , Schatzmann Urs
Published: December 2005

Objective—To compare the cardiopulmonary effects of anesthesia maintained by continuous infusion of ketamine and propofol with anesthesia maintained by inhalation of sevoflurane in goats undergoing magnetic resonance imaging.

Animals—8 Saanen goats.

Procedures—Goats were anesthetized twice (1-month interval) following sedation with midazolam (0.4 mg/kg, IV). Anesthesia was induced via IV administration of ketamine (3 mg/kg) and propofol (1 mg/kg) and maintained with an IV infusion of ketamine (0.03 mg/kg/min) and propofol (0.3 mg/kg/min) and 100% inspired oxygen (K-P treatment) or induced via IV administration of propofol (4 mg/kg) and maintained via inhalation of sevoflurane in oxygen (end-expired concentration, 2.3%; 1X minimum alveolar concentration; SEVO treatment). Cardiopulmonary and blood gas variables were assessed at intervals after induction of anesthesia.

Results—Mean ± SD end-expired sevoflurane was 2.24 ± 0.2%; ketamine and propofol were infused at rates of 0.03 ± 0.002 mg/kg/min and 0.29 ± 0.02 mg/kg/min, respectively. Overall, administration of ketamine and propofol for total IV anesthesia was associated with a degree of immobility and effects on cardiopulmonary parameters that were comparable to those associated with anesthesia maintained by inhalation of sevoflurane. Compared with the K-P treatment group, mean and diastolic blood pressure values in the SEVO treatment group were significantly lower at most or all time points after induction of anesthesia. After both treatments, recovery from anesthesia was good or excellent.

Conclusions and Clinical Relevance—Results suggest that ketamine-propofol total IV anesthesia in goats breathing 100% oxygen is practical and safe for performance of magnetic resonance imaging procedures. (Am J Vet Res2005;66:2135–2141)
Variation in the N-terminal region of an M-like protein of Streptococcus equi and evaluation of its potential as a tool in epidemiologic studies
Authors: Anzai Toru , Kuwamoto Yasushi , Wada Ryuichi , Sugita Sigeo , Kakuda Tsutomu , Takai Shinji , Higuchi Tohru , Timoney John F.
Published: December 2005

Objective—To develop a method for typing
Streptococcus equi on the basis of the DNA
sequence of the genes that produce an M-like protein
and to compare isolates among the United States,
Japan, and other countries.

Sample Population—S equi strains CF32, Hidaka/95/2,
and NCTC9682 as well as 82 other isolates from the
United States, Japan, and other countries obtained during
1975 to 2001.

Procedure—DNA sequences of the structural genes
( SeM and SzPSe) that produce M-like proteins were
determined for 3 representative strains to find a variable
region. Variability in this region of SeM was then
determined for the other isolates. Amino acid
sequences were deduced and analyzed phylogenetically
by use of the neighbor-joining method.

Results—Sequence diversity was detected in the
N-terminal region of SeM but not in SzPSe of the 3
representative strains. Base substitutions in the
variable region of SeM varied in a nonsynonymous
manner, resulting in variation in the amino acid
sequence. Eighty-five isolates were categorized as
32 types of SeM on the basis of differences in the
deduced amino acid sequences.

Conclusions and Clinical Relevance—This study
documented a region in the N-terminal portion of
SeM that varies in a nonsynonymous manner. This
information should be useful in molecular epidemiologic
studies of S equi. (Am J Vet Res 2005;
66:2167–2171)
Disposition of orally administered cefpodoxime proxetil in foals and adult horses and minimum inhibitory concentration of the drug against common bacterial pathogens of horses
Authors: Carrillo Natalie A. , Giguère Steeve , Gronwall Ronald R. , Brown Murray P. , Merritt Kelly A. , O'Kelley Jeffrey J.
Published: December 2005

Objective—To determine the disposition of orally administered cefpodoxime proxetil in foals and adult horses and measure the minimum inhibitory concentrations (MICs) of the drug against common bacterial pathogens of horses.

Animals—6 healthy adult horses and 6 healthy foals at 7 to 14 days of age and again at 3 to 4 months of age.

Procedure—A single dose of cefpodoxime proxetil oral suspension was administered (10 mg/kg) to each horse by use of a nasogastric tube. In 7- to 14-day-old foals, 5 additional doses were administered intragastrically at 12-hour intervals. The MIC of cefpodoxime for each of 173 bacterial isolates was determined by use of a commercially available test.

Results—In 7- to 14-day-old foals, mean ± SD time to peak serum concentration (Tmax) was 1.7 ± 0.7 hours, maximum serum concentration (Cmax) was 0.81 ± 0.22 µg/mL, and elimination half-life (harmonic mean) was 7.2 hours. Disposition of cefpodoxime in 3- to 4-month-old foals was not significantly different from that of neonates. Adult horses had significantly higher Cmaxand significantly lower Tmax, compared with values for foals. The MIC of cefpodoxime required to inhibit growth of 90% of isolates forSalmonella enterica, Escherichia coli, Pasteurellaspp,Klebsiellaspp, and β-hemolytic streptococci was 0.38, 1.00, 0.16, 0.19, and 0.09 µg/mL, respectively.

Conclusions and Clinical Relevance—Oral administration at a dosage of 10 mg/kg every 6 to 12 hours would appear appropriate for the treatment of equine neonates with bacterial infections. (Am J Vet Res2005;66:30–35)
Determination of abomasal emptying rate in suckling calves by use of nuclear scintigraphy and acetaminophen absorption
Authors: Marshall Tessa S. , Constable Peter D. , Crochik Sonia S. , Wittek Thomas
Published: December 2005

Objective—To develop nuclear scintigraphic and acetaminophen absorption methods for measuring abomasal emptying rate in suckling calves.

Animals—9 male Holstein-Friesian calves < 30 days old.

Procedure—Calves were fed 2 L of milk replacer, fresh cow's milk, or an isoosmotic (150mM) solution of NaCl, NaHCO3, or sodium acetate containing technetium TC 99m-diethylenetriamine-pentaacetic acid (370 MBq) and acetaminophen (50 mg/kg). Right lateral scintigraphic images and venous blood samples were obtained periodically after feeding. Two power exponential equations were fitted to the scintigraphic data, and 3 pharmacokinetic models were fitted to the acetaminophen concentration–time data.

Results—Data from 32 feedings were analyzed, with half emptying time for scintigraphic evaluation ranging from 29 to 202 minutes. Siegel's modified power exponential equation provided a better description of the scintigraphic data than did Elashoff's power exponential equation. The first derivative of Siegel's modified power exponential formula provided the best pharmacokinetic model for the acetaminophen absorption data. Time to maximal acetaminophen concentration (Tmax) provided the most accurate index of abomasal emptying rate from the acetaminophen concentration–time data.

Conclusions and Clinical Relevance—Abomasal emptying rate is best determined in healthy suckling calves by use of Siegel's modified power exponential equation to model the scintigraphic data. Pharmacokinetic calculation of Tmax from the acetaminophen absorption curve provides an alternative method for determining abomasal emptying rate in healthy suckling calves that is accurate, inexpensive, practical, and safe. However, it is unclear whether diarrhea would alter the acetaminophen absorption curve in calves. (Am J Vet Res2005;66:364–374)
Assessment of the reliability of plasma electrophoresis in birds
Authors: Rosenthal Karen L. , Johnston Matthew S. , Shofer Frances S.
Published: December 2005

Objective—To determine the reliability of plasma
electrophoresis (EPH) in psittacine birds.

Animals—93 psittacine birds.

Procedure—Jugular venipuncture was performed on
93 awake psittacine birds. The plasma was centrifuged,
separated, aliquoted into duplicate samples,
frozen, and sent to 2 commercial laboratories that
routinely perform avian EPH. Samples from 51 birds
were sent to laboratory A, and samples from 42 birds
were sent to laboratory B. The reliability of EPH
results within each laboratory was assessed, but not
between laboratories. To determine the reliability
(agreement between duplicate samples) of total protein,
albumin, prealbumin, α1-, α2-, β-, and γ-globulin
concentrations, the intraclass correlation coefficient
( ri
) was calculated.

Results—Both laboratories had excellent agreement
between samples for measurement of total protein
concentration and only good agreement for albumin
concentration. Except for the prealbumin concentration
measured at laboratory B, both laboratories had
poor agreement for all other values of the EPH.

Conclusions and Clinical Relevance—These data
indicate that plasma EPH for measuring prealbumin,
α1-, α2-, β-, and γ-globulin concentrations may not be
a reliable tool for assessing avian health. Small
amounts of these proteins in birds plus human variation
in reading the EPH curves may lead to variable
results. Avian veterinarians should cautiously interpret
results from plasma EPH assays for these protein
fractions. (Am J Vet Res 2005;66:375–378)
Expression of equine glucose transporter type 4 in skeletal muscle after glycogen-depleting exercise
Authors: Jose-Cunilleras Eduard , Hayes Kathleen A. , Toribio Ramiro E. , Mathes Lawrence E. , Hinchcliff Kenneth W.
Published: December 2005

Objective—To clone and sequence cDNA for equine insulin-responsive glucose transporter (glucose transporter type 4 [GLUT-4]) and determine effects of glycogen-depleting exercise and meal type after exercise on GLUT-4 gene expression in skeletal muscle of horses.

Animals—Muscle biopsy specimens from 7 healthy adult horses.

Procedure—Total RNA was extracted from specimens, and GLUT-4 cDNA was synthesized and sequenced. Horses were exercised on 3 consecutive days. On the third day of exercise, for 8 hours after exercise, horses were either not fed, fed half of daily energy requirements as hay, or fed an isocaloric amount of corn. The GLUT-4 mRNA was determined by use of realtime reverse transcriptase-polymerase chain reaction in muscle biopsy specimens obtained before 3 consecutive days of exercise and within 10 minutes and 4, 8, and 24 hours after the third exercise bout.

Results—A 1,629-bp segment was sequenced, of which 1,530 bp corresponded to the coding region and encoded a protein of 509 amino acids. Expression of GLUT-4 gene increased by 2.3, 4.3, 3.3, and 2.6 times 10 minutes and 4, 8, and 24 hours after exercise, respectively, compared with that prior to exercise. No differences were observed in GLUT-4 gene expression among conditions of feed withholding, corn feeding, and hay feeding during the 8 hours postexercise.

Conclusions and Clinical Relevance—Lack of increase of GLUT-4 gene expression after grain feeding and exercise may explain the apparently slower rate of glycogen synthesis after exercise in horses relative to that of other species. (Am J Vet Res2005;66:379–385)
Evaluation of the passive function of the biceps brachii muscle-tendon unit in limitation of shoulder and elbow joint ranges of motion in horses
Authors: Nevens Amy L. , Stover Susan M. , Hawkins David A.
Published: December 2005

Objective—To quantify the passive contribution of the biceps brachii muscle-tendon unit to the limits of elbow joint extension during shoulder joint flexion in horses.

Sample Population—Normal right forelimb specimens from 6 Thoroughbred cadavers.

Procedure—Specimens included the scapula, humerus, radius-ulna, biceps brachii muscle-tendon unit, and stabilizers of the shoulder and elbow joints. Specimens were mounted to a rigid board by transfixation pins through the humerus and instrumented for mechanical manipulation of the limb and joint angle and load measurements. Flexion and extension limits of shoulder and elbow joint ranges of motion were measured in each joint separately, while the other joint was fixed. Measurements were made before and after transection of the biceps brachii muscle- tendon unit.

Results—The biceps brachii muscle-tendon unit limited elbow joint extension when the shoulder joint was fixed in flexion, limited shoulder joint flexion when the elbow joint was fixed in extension, and inhibited shoulder joint extension to a lesser degree when the elbow joint was fixed at midrange angles of 75° to 90°.

Conclusions and Clinical Relevance—Clinical manipulation of the elbow joint into hyperextension during shoulder joint flexion is indicative of biceps brachii injury. (Am J Vet Res2005;66:391–400)
Evaluation of developmental changes in the coexpression of myosin heavy chains and metabolic properties of equine skeletal muscle fibers
Authors: Yamano Seiko , Eto Daisuke , Kasashima Yoshinori , Hiraga Atushi , Sugiura Takao , Miyata Hirofumi
Published: December 2005

Objective—To determine the growth-related changes
in metabolic and anatomic properties in equine muscle
fiber type, including hybrid fibers identified with
immunohistochemical analysis.

Animals—24 2-, 6-, 12-, and 24-month-old female
Thoroughbreds.

Procedure—Samples were obtained from the gluteus
medius muscle of all horses. Expression of
myosin heavy chain (MHC) isoforms MHC-I, -IIa, -IIb,
and -IIx in each muscle fiber was detected by use of
4 primary monoclonal antibodies: BA-D5, SC-71, BFF3,
and BF-35, respectively. Five muscle fiber types
(types I, I/IIA, IIA, IIA/IIX, and IIX) were immunohistochemically
identified. The area and activity of succinic
dehydrogenase (SDH) in each fiber type were determined
by use of quantitative histochemical staining
and image analysis.

Results—Although the proportion of type I and IIX
fibers did not change with age, the proportion of type
IIA and IIA/IIX fibers significantly increased and
decreased, respectively, from 2 months to 24 months
of age. The increase in proportion of type IIA fibers
with growth may have been attributable to muscle
fiber-type transition from type IIA/IIX fibers but not
from type IIX fibers. Values for SDH activity and fiber
area in hybrid fiber types were intermediate to those
for their respective pure phenotypes.

Conclusions and Clinical Relevance—Hybrid fibers
have an important role for determining the proportion
of muscle fiber type in horses < 24 months old, and
the metabolic and anatomic properties of the hybrid
fibers are well coordinated, as in mature horses.
(Am J Vet Res 2005;66:401–405)
Effects of ranitidine, famotidine, pantoprazole, and omeprazole on intragastric pH in dogs
Authors: Bersenas Alexa M. E. , Mathews Karol A. , Allen Dana G. , Conlon Peter D.
Published: December 2005

Objective—To identify the normal gastric acid secretion
profile in dogs and determine the degree of gastric
acid suppression associated with 4 gastric acid
suppressants.

Animals—12 healthy Beagles.

Procedure—Intragastric pH was measured continuously
for 24-hour periods with a digital recording system
placed via a gastrostomy tube. Baseline measurements
were obtained when food was withheld
and when dogs were fed a standard diet. Dogs were
then treated with ranitidine (2 mg/kg, IV, q 12 h),
famotidine (0.5 mg/kg, IV, q 12 h), pantoprazole
(1 mg/kg, IV, q 24 h), omeprazole (1 mg/kg, PO, q 24
h), or saline solution for 7 days; intragastric pH was
recorded on days 0, 2, and 6. Subsequently, the
effects of administering famotidine (0.5 mg/kg, IV, q 8
h; 6 dogs) and omeprazole as a suspension (1 mg/kg,
PO, q 12 h; 6 dogs) were evaluated. Median 24-hour
intragastric pH, percentage of time pH was ≥ 3, and
percentage of time pH was ≥ 4 were determined.

Results—Median pH, percentage of time pH was ≥ 3,
and percentage of time pH was ≥ 4 were all significantly
higher when food was withheld than when
dogs were fed. Famotidine, pantoprazole, and
omeprazole significantly suppressed gastric acid
secretion, compared with saline solution, as determined
on the basis of median 24-hour pH and percentages
of time pH was ≥ 3 or ≥ 4. However, ranitidine
did not. Omeprazole suspension suppressed
gastric acid secretion.

Conclusions and Clinical Relevance—Results suggest
that in healthy dogs, famotidine, pantoprazole,
and omeprazole significantly suppress gastric acid
secretion. Twice daily administration of a suspension
of omeprazole, was the only regimen tested that
approached the potential therapeutic efficacy for acidrelated
disease when assessed by criteria used for
human patients. (Am J Vet Res 2005;66:425–431)
Effects of vehicle and region of application on absorption of hydrocortisone through canine skin
Authors: Mills Paul C. , Magnusson Beatrice M. , Cross Sheree E.
Published: December 2005

Objective—To determine the effects of various vehicles on the penetration and retention of hydrocortisone applied to canine skin.

Sample Population—20 canine skin samples obtained from the thorax, neck, and groin regions of 5 Greyhounds.

Procedure—Skin was harvested from dogs after euthanasia and stored at –20°C until required. The skin was then defrosted and placed into diffusion cells, which were maintained at approximately 32°C by a water bath. Saturated solutions of hydrocortisone that contained trace amounts of radiolabelled [14C]-hydrocortisone in each vehicle (ie, PBS solution [PBSS] alone, 50% ethanol [EtOH] in PBSS [wt/wt], and 50% propylene glycol in PBSS [wt/wt]) were applied to the outer (stratum corneum) surface of each skin sample, and aliquots of receptor fluid were collected for 24 hours and analyzed for hydrocortisone.

Results—The maximum flux of hydrocortisone was significantly higher for all sites when dissolved in a vehicle containing 50% EtOH, compared with PBSS alone or 50% propylene glycol, with differences more prominent in skin from the neck region. In contrast, higher residues of hydrocortisone were found remaining within the skin when PBSS alone was used as a vehicle, particularly in skin from the thorax and neck.

Conclusions and Clinical Relevance—Penetration of topically applied hydrocortisone is enhanced when EtOH is used in vehicle formulation. Significant regional differences (ie, among the thorax, neck, and groin areas) are also found in the transdermal penetration and skin retention of hydrocortisone. Variability in clinical response to hydrocortisone can be expected in relation to formulation design and site of application. (Am J Vet Res2005;66:43–47)
Expression of erythropoietin in cats treated with a recombinant adeno-associated viral vector
Authors: Walker Mark C. , Mandell Tamara C. , Crawford P. Cynda , Simon Greg G. , Cahill Kevin S. , Fernandes Peter J. , MacLeod James N. , Byrne Barry J. , Levy Julie K.
Published: December 2005

Objective—To characterize the biological effects of IM administration of a recombinant adeno-associated virus serotype 2 (rAAV2) vector containing feline erythropoietin (fEPO) cDNA and determine whether readministration of the vector or removal of muscle tissue at the injection sites alters those effects.

Animals—10 healthy 7-week-old specific pathogenfree cats.

Procedure—Cats received 1 × 107infective units (iU; n = 3), 1 × 108iU (3), or 1 × 109iU (2) of rAAV2-fEPO vector IM (day 0). Two control cats received an rAAV2 vector containing the LacZ gene (1 × 109iU, IM). In all cats, hematologic variables and serum fEPO concentration were measured at intervals; anti-rAAV2 antibody titer was measured on day 227. In cats that did not respond to treatment, the rAAV2- fEPO vector was readministered. Injection sites were subsequently surgically removed.

Results—Compared with control cats, cats treated with 1 × 109iU of rAAV2-fEPO vector had increased Hct and serum fEPO concentrations. One of these cats developed pure RBC aplasia; its Hct normalized following injection site excision. Cats receiving lower doses of vector had no response; on retreatment, 1 of those cats developed sustained erythrocytosis that persisted despite injection site removal and the others did not respond or responded transiently. Antibodies against rAAV2 were detected in all vector-treated cats.

Conclusions and Clinical Relevance—Gene therapy may be an effective treatment for cats with hypoproliferative anemia. However, rAAV2-fEPO vector administration may result in pure RBC aplasia or pathologic erythrocytosis, and injection site removal does not consistently abolish the biological response. (Am J Vet Res2005;66:450–456)
Investigation of antigen-specific T-cell responses and subcutaneous granuloma development during experimental sensitization of calves with Mycobacterium avium subsp paratuberculosis
Authors: Simutis Frank J. , Cheville Norman F. , Jones Douglas E.
Published: December 2005

Objective—To characterize the early cellular immune response toMycobacterium aviumsubspparatuberculosis( MAP) infection and evaluate the development of granulomatous inflammation at the SC injection site in experimentally inoculated calves.

Animals—Forty-eight 4-week-old calves.

Procedure—Calves received an SC injection of MAP strain 19698 (n = 25), sterile saline (0.9% NaCl) solution (20), or a commercial paratuberculosis vaccine (3); the inoculation site tissue and associated draining lymph node were excised at postinoculation day (PID) 0 (n = 36), 7 (14), 14 (6), 21 (8), and 60 (32). Sections of inoculation site tissues were evaluated immunohistochemically for T-cell subsets; lymph node mononuclear cells (LNMCs) were assessed for T-cell surface markers and for intracellular interferon-γ via flow cytometry.

Results—At MAP inoculation sites, calves developed mild, focal granulomatous inflammation by PID 7; by PID 60, areas of inflammation contained macrophages with numerous lymphocytes. Compared with control calves, there was increased antigen-specific LNMC proliferation in MAP- and vaccine- inoculated calves at PID 60, although proliferation among lymphocyte subsets was not significantly different between MAP-inoculated and control calves; in vaccine-inoculated calves, CD4+ T-cells predominated. In MAP-inoculated and control calves, antigenspecific interferon-γ production by LNMCs did not differ significantly; vaccine-inoculated calves had marked interferon-γ expression by CD4+ T-cells.

Conclusions and Clinical Relevance—In calves, SC administration of MAP resulted in granulomatous inflammation at inoculation sites and an antigen-specific T-cell proliferative response. Results suggest that this experimental system can be used to reproducibly generate antigen-specific T-cells during MAP infection for functional analysis. (Am J Vet Res2005;66:474–482)
Effects of CD28 blockade on subsets of naïve T cells in cats
Authors: Aronson Lillian R. , Drobatz Kenneth J. , Hunter Christopher A. , Mason Nicola
Published: December 2005

Objective—To determine whether human CTLA4-Ig ([hu]CTLA4-Ig) inhibits costimulation-dependent lymphocyte proliferation in vitro, compare the effects of (hu)CTLA4-Ig with cyclosporine and steroids on CD4+ and CD8+ T-cell lymphocyte proliferation, and determine whether memory T-cell function remains intact in the presence of (hu)CTLA4-Ig.

Animals—29 cats.

Procedure—Peripheral blood mononuclear cells (PBMCs) were stimulated with concanavalin A (costimulation- dependent mitogen) or phorbol 12-myristate 13-acetate and ionomycin (costimulation independent mitogens) alone or in the presence of (hu)CTLA4-Ig, cyclosporine, or dexamethasone; effects of these treatments on lymphocyte proliferation were assessed by incorporation of thymidine labeled with tritium or flow cytometry. Antigen-specific proliferation was determined by stimulating PBMCs from 2 healthy cats seropositive forToxoplasma gondiiwith solubleToxoplasmaantigen alone or in the presence of (hu)CTLA4-Ig or cyclosporine.

Results—(hu)CTLA4-Ig inhibited costimulationdependent lymphocyte proliferation in vitro but had no effect on costimulation-independent lymphocyte proliferation. Compared with mitogen alone, (hu)CTLA4-Ig caused a significant decrease in responder frequency and proliferative capacity of CD4+ T cells; however, the effect on CD8+ T cells was not significant. Cyclosporine alone or with dexamethasone had a significantly greater suppressive effect on responder frequency and proliferative capacity of CD4+ and CD8+ T cells, compared with (hu)CTLA4-Ig. Compared with cyclosporine, (hu)CTLA4-Ig appeared to have a sparing effect on antigen-specific proliferation of memory CD4+ and CD8+ T cells.

Conclusions and Clinical Relevance—(hu)CTLA4-Ig selectively inhibited costimulation-dependent proliferation of lymphocytes in vitro and had a sparing effect on antigen-specific proliferation of memory cells. The specificity of its mechanism of action suggests that (hu)CTLA4-Ig may prevent allograft rejection but leave memory responses to previously encountered antigens intact. (Am J Vet Res2005;66:483–492)
Ultrasonographic measurement of abomasal volume, location, and emptying rate in calves
Authors: Wittek Thomas , Constable Peter D. , Marshall Tessa S. , Crochik Sonia S.
Published: December 2005

Objective—To develop and validate an ultrasonographic method for measuring abomasal volume, location, and emptying rate in suckling calves.

Animals—9 male Holstein calves < 40 days of age.

Procedure—Before and after calves were fed different volumes of milk replacer or 2 L of oral electrolyte solutions, ultrasonographic measurements of abomasal dimensions (width, length, and height) were obtained by applying a 3.5-MHz sector probe to the ventral aspect of the abdomen in the transverse and sagittal planes. Abomasal volume was calculated from the ultrasonographic measurements by modeling the abomasum as an ellipsoid and by use of a power exponential equation to calculate the half-time of abomasal emptying (t1/2).

Results—Preprandial abomasal volume was 20 to 137 mL. All 3 abomasal dimensions increased during feeding and after suckling, and the abomasum was symmetrically located about the midline of the ventral aspect of the abdomen. Strong linear relationships were identified between ultrasonographic and suckled volumes, between ultrasonographic and scintigraphic heights, and between ultrasonographic and scintigraphic lengths. Ultrasonographic t1/2was linearly related to scintigraphic t1/2; the latter is regarded as the gold standard measure of gastric emptying rate.

Conclusions and Clinical Relevance—Ultrasonographic evaluation of the abomasum appears to provide a practical, rapid, noninvasive, and accurate method for determination of abomasal volume, location, and emptying rate in suckling calves. (Am J Vet Res2005;66:537–544)
Tracheobronchoscopic assessment of exercise-induced pulmonary hemorrhage in horses
Authors: Hinchcliff Kenneth W. , Jackson Melissa A. , Brown James A. , Dredge Anthony F. , O'Callaghan Paul A. , McCaffrey John P. , Morley Paul S. , Slocombe Ronald F. , Clarke Andrew F.
Published: December 2005

Objective—To determine the interobserver variability
of assessment of exercise-induced pulmonary hemorrhage
(EIPH) during tracheobronchoscopic examination
in horses.

Animals—747 Thoroughbred racehorses.

Procedure—850 tracheobronchoscopic examinations
were performed within 2 hours of racing for the
horses. Examinations were recorded on videotape,
and EIPH and its severity were assessed independently
by 3 veterinarians. Concordance was determined
by calculation of the Cohen weighted κ statistic
and tabulation of scores assigned by each observer.

Results—Weighted κ statistics ranged from 0.75 to
0.80. In 99.4% of observations, all observers agreed
or 2 of 3 agreed and the third differed by ≤ 1 grade.

Conclusions and Clinical Relevance—Results indicated
that interobserver reliability of tracheobronchoscopic
assessment of EIPH in Thoroughbred racehorses
is high when the examination is conducted by
experienced veterinarians. Concordance among
investigators is sufficient to justify use of this grading
system for further studies and clinical descriptions of
EIPH. (Am J Vet Res 2005;66:596–598)
Evaluation of vacuum and dynamic cell seeding of polyglycolic acid and chitosan scaffolds for cartilage engineering
Authors: Griffon Dominique J. , Sedighi M. Reza , Sendemir-Urkmez Aylin , Stewart Allison A. , Jamison Russell
Published: December 2005

Objectives—To compare combined vacuum and rotation
with the spinner flask technique for seeding
chondrocytes on chitosan versus polyglycolic acid
matrices.

Sample Population—Porcine chondrocytes.

Procedure—A suspension containing 5 × 106 chondrocytes/
scaffold was used to evaluate 2 seeding
techniques, including a spinner flask and a customdesigned
vacuum chamber used for 2 hours prior to
transfer to a bioreactor. For each seeding technique,
prewetted scaffolds were composed of polyglycolic
acid (PGA) mesh or macroporous chitosan sponge.
Constructs were collected at 48 hours for DNA quantification,
measurement of water and gycosaminoglycan
(GAG) content, and scanning electron
microscopy.

Results—Yield of both seeding techniques was similar
for each type of scaffold. Percentage of cells contained
in the center of PGA constructs was increased
with seeding in the bioreactor (43% of total cell number),
compared with the spinner flask (18%). The DNA
content and cell number per construct were 10 times
greater for PGA constructs, compared with chitosan
constructs. Chitosan scaffolds seeded in the bioreactor
yielded a significantly higher GAG:DNA ratio than
did PGA scaffolds. Whereas chondrones formed on
chitosan scaffolds, cell distribution was more uniform
on PGA scaffolds.

Conclusions and Clinical Relevance—The vacuumbioreactor
technique allowed seeded chondrocytes to
attach to PGA scaffolds within 48 hours and improved
uniformity of cell distribution, compared with the
spinner technique. Although formation of extracellular
matrix may be stimulated by seeding chitosan scaffolds
in the bioreactor, further evaluations of the seeding
technique and characteristics of chitosan scaffolds
are warranted. (Am J Vet Res 2005;66:599–605)
Effects of sevoflurane dose and mode of ventilation on cardiopulmonary function and blood biochemical variables in horses
Authors: Steffey Eugene P. , Mama Khursheed R. , Galey Frank D. , Puschner Birgit , Woliner Michael J.
Published: December 2005

Objective—To quantitate effects of dose of sevoflurane and mode of ventilation on cardiovascular and respiratory function in horses and identify changes in serum biochemical values associated with sevoflurane anesthesia.

Animals—6 healthy adult horses.

Procedure—Horses were anesthetized twice: first, to determine the minimum alveolar concentration (MAC) of sevoflurane and second, to characterize cardiopulmonary and serum biochemical responses of horses to 1.0, 1.5, and 1.75 MAC multiples of sevoflurane during controlled and spontaneous ventilation.

Results—Mean (± SEM) MAC of sevoflurane was 2.84 ± 0.16%. Cardiovascular performance during anesthesia decreased as sevoflurane dose increased; the magnitude of cardiovascular depression was more severe during mechanical ventilation, compared with spontaneous ventilation. Serum inorganic fluoride concentration increased to a peak of 50.8 ± 7.1 µmol/L at the end of anesthesia. Serum creatinine concentration and sorbitol dehydrogenase activity reached their greatest values (2.0 ± 0.8 mg/dL and 10.2 ± 1.8 U/L, respectively) at 1 hour after anesthesia and then returned to baseline by 1 day after anesthesia. Serum creatine kinase, aspartate aminotransferase, and alkaline phosphatase activities reached peak values by the first (ie, creatine kinase) or second (ie, aspartate aminotransferase and alkaline phosphatase) day after anesthesia.

Conclusions and Clinical Relevance—Sevoflurane causes dose-related cardiopulmonary depression, and mode of ventilation further impacts the magnitude of this depression. Except for serum inorganic fluoride concentration, quantitative alterations in serum biochemical indices of liver- and muscle-cell disruption and kidney function were considered clinically unremarkable and similar to results from comparable studies of other inhalation anesthetics. (Am J Vet Res2005;66:606–614)
Computer-assisted kinematic evaluation of induced compensatory movements resembling lameness in horses trotting on a treadmill
Authors: Kelmer Gal , Keegan Kevin G. , Kramer Joanne , Wilson David A. , Pai Frank P. , Singh Prableen
Published: December 2005

Objective—To characterize compensatory movements of the head and pelvis that resemble lameness in horses.

Animals—17 adult horses.

Procedure—Kinematic evaluations were performed while horses trotted on a treadmill before and after shoe-induced lameness. Lameness was quantified and the affected limb determined by algorithms that measured asymmetry in vertical movement of the head and pelvis. Induced primary lameness and compensatory movements resembling lameness were assessed by the Friedman test. Association between induced lameness and compensatory movements was examined by regression analysis.

Results—Compensatory movements resembling lameness in the ipsilateral forelimb were seen with induced lameness of a hind limb. There was less downward and less upward head movement during and after the stance phase of the ipsilateral forelimb. Doubling the severity of lameness in the hind limb increased severity of the compensatory movements in the ipsilateral forelimb by 50%. Compensatory movements resembling lameness of the hind limb were seen after induced lameness in a forelimb. There was less upward movement of the pelvis after the stance phase of the contralateral hind limb and, to a lesser extent, less downward movement of the pelvis during the stance phase of the ipsilateral hind limb. Doubling the severity of lameness in the forelimb increased compensatory movements of the contralateral hind limb by 5%.

Conclusions and Clinical Relevance—Induced lameness in a hind limb causes prominent compensatory movements resembling lameness in the ipsilateral forelimb. Induced lameness in a forelimb causes slight compensatory movements resembling lameness in the ipsilateral and contralateral hind limbs. (Am J Vet Res2005;66:646–655)
Assessment of the hemodynamic effects of lidocaine administered IV in isofluraneanesthetized cats
Authors: Pypendop Bruno H. , Ilkiw Jan E.
Published: December 2005

Objective—To determine the hemodynamic effects of lidocaine (administered IV to achieve 6 plasma concentrations) in isoflurane-anesthetized cats.

Animals—6 cats.

Procedure—Cats were anesthetized with isoflurane in oxygen (end-tidal isoflurane concentration set at 1.25 times the predetermined individual minimum alveolar concentration). Lidocaine was administered IV to each cat to achieve target pseudo–steady-state plasma concentrations of 0, 3, 5, 7, 9, and 11 µg/mL, and isoflurane concentration was reduced to an equipotent concentration. At each plasma lidocaine concentration, cardiovascular and blood gas variables; PCV; and plasma total protein, lactate, lidocaine, and monoethylglycinexylidide concentrations were measured in cats before and during noxious stimulation. Derived variables were calculated.

Results—In isoflurane-anesthetized cats, heart rate, cardiac index, stroke index, right ventricular stroke work index, plasma total protein concentration, mixed-venous PO2and hemoglobin oxygen saturation, arterial and mixed-venous bicarbonate concentrations, and oxygen delivery were significantly lower during lidocaine administration, compared with values determined without lidocaine administration. Mean arterial pressure, central venous pressure, pulmonary artery pressure, systemic and pulmonary vascular resistance indices, PCV, arterial and mixed-venous hemoglobin concentrations, plasma lactate concentration, arterial oxygen concentration, and oxygen extraction ratio were significantly higher during administration of lidocaine, compared with values determined without lidocaine administration. Noxious stimulation did not significantly affect most variables.

Conclusions and Clinical Relevance—In isofluraneanesthetized cats, although IV administration of lidocaine significantly decreased inhalant requirements, it appeared to be associated with greater cardiovascular depression than an equipotent dose of isoflurane alone. Administration of lidocaine to reduce isoflurane requirements is not recommended in cats. (Am J Vet Res2005;66:661–668)
Effect of a ventral slot procedure and of smooth or positive-profile threaded pins with polymethylmethacrylate fixation on intervertebral biomechanics at treated and adjacent canine cervical vertebral motion units
Authors: Koehler Carl L. , Stover Susan M. , LeCouteur Richard A. , Schulz Kurt S. , Hawkins David A.
Published: December 2005

Objective—To investigate the biomechanics of cervical vertebral motion units (VMUs) before and after a ventral slot procedure and after subsequent pin-polymethylmethacrylate (pin-PMMA) fixation and to assess the use of smooth and positive-profile threaded (PPT) pins in pin-PMMA fixation and intravertebral pin placement.

Sample Population—Cervical portions (C3 through C6 vertebrae) of 14 cadaveric canine vertebral columns.

Procedure—Flexion and extension bending moments were applied to specimens before and after creation of a ventral slot across the C4-C5 intervertebral space and after subsequent smooth or PPT pin-PMMA fixation at that site. Data for the C3-C4, C4-C5, and C5-C6 VMUs were compared among treatments and between pin types, and pin protrusion was compared between pin types.

Results—Compared with values in intact specimens, ventral slot treatment increased neutral zone range of motion (NZ-ROM) by 98% at the treated VMUs and appeared to decrease overall ROM at adjacent VMUs; pin-PMMA fixation decreased NZ-ROM by 92% at the treated VMUs and increased overall NZ-ROM by 19% to 24% at adjacent VMUs. Specimens fixed with PPT pins were 82% (flexion) and 80% (extension) stiffer than smooth–pin-fixed specimens. Overall, 41% of pins protruded into foramina; PPT pins were more likely to protrude into transverse foramina.

Conclusions and Clinical Relevance—Results indicated that fixation of a cervical VMU alters the biomechanics of adjacent VMUs and may contribute to degeneration of adjacent intervertebral disks. Use of threaded pins may lower the incidence of pin loosening and implant failure but enhances the likelihood of transverse foramina penetration. (Am J Vet Res2005;66:678–687)