bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of a chemokine by ciliary body epithelium in horses with naturally occurring recurrent uveitis and in cultured ciliary body epithelial cells
Authors: Gilger Brian C. , Yang Ping , Salmon Jacklyn H. , Jaffe Glenn J. , Allen Janice B.
Published: January 2006

Objective—To determine whether a chemokine (RANTES)-like protein expressed by ciliary epithelium plays a role in uveitis.

Sample Population—3 clinically normal horses intradermal, 5 eyes from 5 horses with recurrent uveitis, and 10 normal eyes from 5 age- and sex-matched horses.

Procedure—Cross-reactivity and sensitivity of recombinant human (rh)-regulated upon activation, normal T-cell expressed and secreted (RANTES) protein were evaluated in horses by use of intradermal hypersensitivity reactions and a chemotaxis assay. Aqueous humor and ciliary body of eyes from clinically normal horses and horses with uveitis were examined for RANTES expression by use of an ELISA and reverse transcription-polymerase chain reaction (RT-PCR). Expression of RANTES mRNA and protein content of primary cultures of equine ciliary pigmented epithelial cells (RT-PCR) and culture supernatant (ELISA) were measured 6 or 24 hours, respectively, after cultures were stimulated with interleukin-1β and tumor necrosis factor-α.

Results—Strong reactions to intradermal hypersensitivity testing and significant chemotaxis of equine leukocytes to rh-RANTES wereas observed. Aqueous humor of eyes from horses with uveitis contained increased concentrations of rh-RANTES-like protein (mean ± SD, 45.9 ± 31.7 pg/ml), compared with aqueous humor from clinically normal horses (0 pg/ml). Ciliary body from horses with uveitis expressed RANTES mRNA, whereas ciliary body from clinically normal horses had low mRNA expression. Stimulated ciliary pigmented epithelial cells expressed increased amounts of rh-RANTES-like protein (506.1 ± 298.3 pg/ml) and mRNA, compared with unstimulated samples.

Conclusions and Clinical Relevance—Ciliary epithelium may play a role in recruitment and activation of leukocytes through expression of RANTES. (Am J Vet Res2002;63:942–947)
Evaluation of the perioperative stress response in dogs administered medetomidine or acepromazine as part of the preanesthetic medication
Authors: Väisänen Misse , Raekallio Marja , Kuusela Erja , Huttunen Pirkko , Leppäluoto Juhani , Kirves Petra , Vainio Outi
Published: January 2006

Objective—To compare the perioperative stress response in dogs administered medetomidine or acepromazine as part of the preanesthetic medication.

Animals—42 client-owned dogs that underwent elective ovariohysterectomy.

Procedure—Each dog was randomly allocated to receive medetomidine and butorphanol tartrate (20 µg/kg and 0.2 mg/kg, respectively, IM) or acepromazine maleate and butorphanol (0.05 and 0.2 mg/kg, respectively, IM) for preanesthetic medication. Approximately 80 minutes later, anesthesia was induced by administration of propofol and maintained by use of isoflurane in oxygen. Each dog was also given carprofen before surgery and buprenorphine after surgery. Plasma concentrations of epinephrine, norepinephrine, cortisol, and β-endorphin were measured at various stages during the perioperative period. In addition, cardiovascular and clinical variables were monitored.

Results—Concentrations of epinephrine, norepinephrine, and cortisol were significantly lower for dogs administered medetomidine. Concentrations of β-endorphin did not differ between the 2 groups. Heart rate was significantly lower and mean arterial blood pressure significantly higher in dogs administered medetomidine, compared with values for dogs administered acepromazine.

Conclusions and Clinical Relevance—Results indicate that for preanesthetic medications, medetomidine may offer some advantages over acepromazine with respect to the ability to decrease perioperative concentrations of stress-related hormones. In particular, the ability to provide stable plasma catecholamine concentrations may help to attenuate perioperative activation of the sympathetic nervous system. (Am J Vet Res2002;63:969–975)
Linear, logarithmic, and polynomial models of M-mode echocardiographic measurements in dogs
Authors: Gonçalves Ana C. , Orton E. Christopher , Boon June A. , Salman M. D.
Published: January 2006

Objective—To determine whether logarithmic and polynomial models are superior to simple linear models for predicting reference values for M-mode echocardiographic variables in dogs with a wide range of body weights.

Animals—69 apparently healthy adult male and female dogs of various breeds, ages (range, 1 to 12 years; median, 3.5 years), and body weights (range, 3.9 to 97.7 kg; median, 25.4 kg).

Procedure—Echocardiographic M-mode measurements of the interventricular septum, left ventricular dimension (LVD), left ventricular wall, aorta, and left atrium were obtained. Simple linear, second-order polynomial, third-order polynomial, and logarithmic regression models were determined by use of the least-squares method to describe the relationship between M-mode measurements and body weight. Differences in adjustedR2values of logarithmic and polynomial models were tested for significance of contribution, compared with the simple linear model.

Results—Significant differences in adjustedR2 were found when comparing simple linear with logarithmic or polynomial models for LVD-diastole, LVD-systole, aorta, and left atrium. Differences in adjusted R2 between second-order polynomial, third-order polynomial, and logarithmic models were not significant for any M-mode measurement.

Conclusions and Clinical Relevance—In this study, logarithmic or second-order polynomial models predicted reference values of M-mode measurements for size of the cardiac chambers better than simple linear models for dogs with a wide range of body weights. Logarithmic and polynomial models were not superior to simple linear models for M-mode measurements of cardiac wall thickness. (Am J Vet Res2002;63:994–999)
Biocompatibility of three-dimensional chondrocyte grafts in large tibial defects of rabbits
Authors: Cook James L. , Williams Ned , Kreeger John M. , Peacock John T. , Tomlinson James L.
Published: January 2006

Objective—To evaluate biocompatibility and effects of implantation of 3-dimensional chondrocyte-agarose autografts in tibial defects in rabbits and to compare in vitro and in vivo chondrocyte-agarose constructs with respect to cell viability, differentiation, and matrix production.

Animals—24 adult New Zealand White rabbits.

Procedure—Three-dimensional constructs with (grafted group) or without (control group) autogenous chondrocytes were implanted into tibial defects of rabbits and cultured in vitro. During an 8-week period, defects were evaluated radiographically, grossly, histologically, biochemically, and immunohistochemically. In vitro constructs were evaluated histologically, biochemically, and immunohistochemically.

Results—Tibial defects had significantly higher radiographic densitometry values at 4 and 6 weeks after implantation in grafted group rabbits, compared with control group rabbits. Number of observed centers of endochondral ossification was significantly greater in defects of grafted group rabbits, compared with control group rabbits. On day 14, glycosaminoglycan concentration was significantly higher in tibial defects of grafted group rabbits, compared to defects of control group rabbits or in vitro constructs. At weeks 2, 4, and 8, glycosaminoglycan concentrations were significantly lower in the in vitro control constructs, compared with other groups. Collagen type I was present in bone and bony callous in defects of grafted and control group rabbits. Collagen type II was identified in cartilaginous tissues of grafted and control group rabbits. Collagen type X was associated with hypertrophic chondrocytes. Only type II collagen was found in the in vitro chondrocyte constructs.

Conclusion and Clinical Relevance—Chondrocyte-agarose grafts are biocompatible in large tibial defects and appear to provide a cell source for augmenting endochondral ossification. (Am J Vet Res2003;64:12–20)
Effects of acetylcysteine and migration of resident eosinophils in an in vitro model of mucosal injury and restitution in equine right dorsal colon
Authors: Rötting Anna K. , Freeman David E. , Eurell Jo Ann C. , Constable Peter D. , Wallig Matthew
Published: January 2006

Objectives—To evaluate the in vitro protective effects of acetylcysteine and response of resident mucosal eosinophils in oxidant-induced injury to tissues of right dorsal colon of horses.

Animals—9 adult horses.

Procedure—Gastrointestinal mucosa was damaged in vitro with 3mM hypochlorous acid (HOCl), with and without prior exposure to 6mM acetylcysteine. Control tissues were not exposed to HOCl or acetylcysteine. Control and damaged tissues were incubated in Krebs-Ringer-bicarbonate solution and tissue resistance measured during 240 minutes. Tissue permeability to radiolabeled mannitol was also used to assess mucosal barrier integrity. Tissues were examined by light microscopy before and after HOCl exposure and during and after incubation.

Results—Exposure to HOCl caused tissue damage and decreased tissue resistance. Restitution did occur during the incubation period. Eosinophils were located near the muscularis mucosae in freshly harvested tissues and migrated towards the luminal surface in response to HOCl-induced injury. Compared with tissues treated with HOCl without acetylcysteine, pretreatment with acetylcysteine prevented HOCl-induced tissue damage, changes in resistance, and histologically detectable eosinophil migration. The permeability to mannitol increased to the same extent in tissues treated with HOCl alone or with acetylcysteine and HOCl.

Conclusions and Clinical Relevance—Eosinophils migrated toward the mucosal surface in equine colon in response to oxidant-induced damage in vitro. This novel finding could be relevant to inflammation in equine colon and a pathophysiologic feature of many colonic diseases. Acetylcysteine protected the mucosa against oxidant-induced injury and may be useful as a treatment option for various gastrointestinal tract disorders in horses. (Am J Vet Res2003;64:1205–1212)
Determination of reference range values indicative of glucose metabolism and insulin resistance by use of glucose clamp techniques in horses and ponies
Authors: Rijnen Kim E. P. M. , van der Kolk Johannes H.
Published: January 2006

Objectives—To acquire reference range values
indicative of glucose metabolism by use of the hyperglycemic
clamp technique in healthy horses and evaluate
the usefulness of the euglycemic hyperinsulinemic
clamp technique in healthy horses and ponies.

Animals—5 Dutch Warmblood horses and 4 Shetland
ponies.

Procedure—The hyperglycemic clamp technique was
used for quantification of the sensitivity of beta cells
to exogenous glucose infusion in horses. The euglycemic
hyperinsulinemic clamp technique was used
to determine the sensitivity and responsiveness of
tissues to exogenous insulin in horses and ponies.

Results—During the hyperglycemic clamp technique,
the mean amount of glucose metabolized (M) in horses
was 0.011 ± 0.0045 mmol/kg·min–1 (95% confidence
interval [CI], 0.0018 to 0.020 mmol/kg·min–1;
range, 0.000035 to 0.021 mmol/kg·min–1) and the
mean M value-to-plasma insulin concentration (I) ratio
(ie, mmol of glucose/kg·min–1 per pmol of insulin/L X
100) was 0.017 ± 0.016 (95% CI, –0.014 to 0.049;
range, 0.000025 to 0.055). During the euglycemic
hyperinsulinemic clamp technique, the mean M value
was 0.014 ± 0.0055 mmol/kg·min–1 (95% CI, 0.0026 to
0.025 mmol/kg·min–1; range, 0.0042 to 0.023
mmol/kg·min–1) in horses and 0.0073 ± 0.0020
mmol/kg·min–1 (95% CI, 0.0034 to 0.011
mmol/kg·min–1; range, 0.0049 to 0.011 mmol/kg·min–1)
in ponies. The M value was significantly lower in
ponies than in horses, whereas the M:I ratios were
not significantly different between horses and ponies.

Conclusion and Clinical Relevance—Glucose clamp
techniques offer good methods to investigate glucose
metabolism in horses and ponies. A higher degree of
insulin resistance was found in ponies, compared with
Dutch Warmblood horses. (Am J Vet Res 2003;64: 1260–1264)
Effect of first-pass hepatic metabolism on the disposition of levamisole after intravenous administration in rabbits
Authors: Villanueva Irma , Diez M. José , García Juan J. , Fernández M. Nélida , Sahagún Ana M. , Sierra Ana , Sierra Matilde
Published: January 2006

Objective—To evaluate the contribution of first-pass hepatic metabolism of levamisole on levamisole disposition in rabbits.

Animals—30 male New Zealand White rabbits.

Procedures—Rabbits were randomly placed into 2 groups. Rabbits in the first group received levamisole via the marginal ear vein at the following 3 doses: 12.5, 16, and 20 mg/kg (5 rabbits for each dose). Rabbits of the second group received levamisole via the jejunal vein at the same doses (5 rabbits each). During the following 240-minute period, plasma samples were obtained and quantified for levamisole concentrations by reversed-phase high-performance liquid chromatography.

Results—No significant differences were found between pharmacokinetic parameters calculated by compartmental or noncompartmental analysis. Mean hepatic extraction ratio ranged from –0.044 to 0.017 and from 0.020 to 0.081 when area under the plasma concentration-time curve values were obtained after compartmental or noncompartmental analysis, respectively. After compartmental analysis, plasma concentration decreased bi-exponentially. Mean pharmacokinetic parameter values were as follows for each dose (12.5, 16, and 20 mg/kg, respectively): after levamisole administration via the marginal ear vein, volume of distribution at steady state (Vss) = 4.26, 4.33, and 3.20 L/kg; total body clearance (Cl) = 49.04, 43.77, and 39.26 mL/kg·min; and half-life associated with β-phase (t1/2β) = 77.93, 85.39, and 69.79 minutes. After levamisole administration via the jejunal vein, Vss= 4.38, 2.85, and 2.97 L/kg; Cl = 48.14, 42.40, and 39.69 mL/kg·min; and t1/2b= 101.9, 76.71, and 76.13 minutes.

Conclusions—Levamisole has a low degree of hepatic extraction in rabbits. (Am J Vet Res2003;64: 1283–1287)
Comparison of the effect of propofol and sevoflurane on the urethral pressure profile in healthy female dogs
Authors: Byron Julie K. , March Philip A. , DiBartola Stephen P. , Chew Dennis J. , Muir III William W.
Published: January 2006

Objective—To compare the effects of propofol and sevoflurane on the urethral pressure profile in female dogs.

Animals—10 healthy female dogs.

Procedure—Urethral pressure profilometry was performed in awake dogs, during anesthesia with sevoflurane at 1.5, 2.0, and 3.0% end-tidal concentration, and during infusion of propofol at rates of 0.4, 0.8, and 1.2 mg/kg/min. A consistent plane of anesthesia was maintained for each anesthetic protocol. Maximum urethral pressure, maximum urethral closure pressure, functional profile length, and functional area were measured.

Results—Mean maximum urethral closure pressure of awake dogs was not significantly different than that of dogs anesthetized with propofol at all infusion rates or with sevoflurane at 1.5 and 2.0% end-tidal concentration. Functional area in awake dogs was significantly higher than in anesthetized dogs. Functional area of dogs during anesthesia with sevoflurane at 3.0% end-tidal concentration was significantly lower than functional area for other anesthetic protocols. Individual differences in the magnitude of effects of propofol and sevoflurane on urethral pressures were observed.

Conclusions and Clinical Relevance—Sevoflurane is an alternative to propofol for anesthesia in female dogs undergoing urethral pressure profilometry. Use of these anesthetics at appropriate administration rates should reliably distinguish normal from abnormal maximum urethral closure pressures and functional areas. Titration of anesthetic depth is a critical component of urodynamic testing. (Am J Vet Res2003;64:1288–1292)
Evaluation of T lymphocytes in captive African lions (Panthera leo) infected with feline immunodeficiency virus
Authors: Bull Marta E. , Kennedy-Stoskopf Suzanne , Levine Jay F. , Loomis Michael , Gebhard Douglas G. , Tompkins Wayne A.F.
Published: January 2006

Objective—To determine whether FIV infection in captive African lions is associated with changes in immune cell variables similar to those detected in domestic cats infected with FIV.

Animals—5 captive African lions naturally infected with FIV (FIV+) and 5 lions not infected with FIV (FIV–).

Procedure—Peripheral blood samples were collected from FIV+lions during annual examinations conducted during a 7-year period and at a single time point from the FIV–lions. From results of CBC and flow cytometry, lymphocyte subsets were characterized and compared.

Results—Flow cytometric analysis revealed that the percentage and absolute number of CD4+and CD8+T cells were significantly lower in FIV+ lions, compared with these values in FIV– lions. In FIV+lions, severe depletion in the absolute number of CD4+and CD8+T cells was detected, although this did not correlate with clinical signs. Muscle wasting was the most consistent clinical sign of infection.

Conclusions and Clinical Relevance—Results suggest that FIV+African lions develop lymphocyte deficiencies, including significant decreases in the absolute number of CD4+and CD8+T cells; these findings of immune dysfunction are similar to those defined for FIV+domestic cats. It is important to monitor the number of CD4+T cells in infected animals as a measure of disease progression. (Am J Vet Res2003; 64:1293–1300)
Effects of iron modulation on growth and viability of Rhodococcus equi and expression of virulence-associated protein A
Authors: Jordan Misty C. , Harrington Jessica R. , Cohen Noah D. , Tsolis Renee M. , Dangott Lawrence J. , Weinberg Eugene D. , Martens Ronald J.
Published: January 2006

Objective—To determine the importance of iron for in vitro growth ofRhodococcus equi, define potential iron sources in the environment and mechanisms by whichR equimay obtain iron from the environment, and assess expression and immunogenicity of iron-regulated proteins.

Sample Population—10 virulent and 11 avirulent strains ofR equi.

Procedure—In vitro growth rates and protein patterns ofR equipropagated in media with normal, excess, or limited amounts of available iron were compared. Immunoblot analyses that used serum from foals naturally infected withR equiand monoclonal antibody against virulence-associated protein (Vap)A were conducted to determine immunogenicity and identity of expressed proteins.

Results—Excess iron did not alter growth of anyR equistrains, whereas growth of all strains was significantly decreased in response to limited amounts of available iron. VirulentR equiwere able to use iron from ferrated deferoxamine, bovine transferrin, and bovine lactoferrin. Only virulentR equiexpressed an iron-regulated, immunogenic, surface-associated protein identified as VapA.

Conclusions and Clinical Relevance—Iron is required for the growth and survival ofR equi. Sources of iron forR equi, and mechanisms by whichR equiacquire iron in vivo, may represent important virulence factors and novel targets for the development of therapeutic and immunoprophylactic strategies to controlR equiinfection in foals. Expression of VapA is substantially upregulated when there is a limited amount of available iron. (Am J Vet Res2003;64:1337–1346)
Evaluation of gradual occlusion of the caudal vena cava in clinically normal dogs
Authors: Peacock John T. , Fossum Theresa W. , Bahr Anne M. , Miller Matthew W. , Edwards John F.
Published: January 2006

Objective—To devise a technique for gradual occlusion of the caudal vena cava in dogs and determine effects of complete occlusion of the caudal vena cava.

Animals—8 mixed-breed hounds that weighed between 25 and 30 kg.

Procedure—Baseline evaluation of dogs included serum biochemical analyses and determination of glomerular filtration rate (GFR) with dynamic renal scintigraphy and plasma clearance analysis. An occluder was placed around the vena cava in the region cranial to the renal veins. The occluder was attached to a vascular access port. The vena cava was gradually occluded over 2 weeks. The GFR was measured every 2 weeks after surgery, and venograms were performed every 3 weeks after surgery. Blood samples were collected every 48 hours for the first week and then weekly thereafter to measure BUN and creatinine concentrations and activities of alanine transaminase, alkaline phosphatase, and creatinine kinase. Dogs were euthanatized 6 weeks after surgery, and tissues were submitted for histologic examination. The GFR and biochemical data were compared with baseline values.

Results—Gradual occlusion of the caudal vena cava was easily and consistently performed with this method, and adverse clinical signs were not detected. Formation of collateral vessels allowed overall GFR to remain constant despite a decrease in function of the left kidney. Measured biochemical values did not deviate from reference ranges.

Conclusions and Clinical Relevance—Gradual occlusion of the caudal vena cava may allow removal of adrenal gland tumors with vascular invasion that would otherwise be difficult or impossible to resect. (Am J Vet Res2003;64:1347–1353)
Assessment of the reliability of a technique to measure postural sway in horses
Authors: Clayton Hilary M. , Bialski David E. , Lanovaz Joel L. , Mullineaux David R.
Published: January 2006

Objective—To assess the reliability of the center-ofpressure
(COP) values obtained from a force platform
for analysis of postural sway in horses.

Animals—Six 2-year-old horses that were free from
lameness and neurologic disease.

Procedure—Horses stood stationary with all 4
hooves on a force platform; COP data were collected
at 1,000 Hz and 3-dimensional kinematics collected at
60 Hz for 10 seconds. Five trials were recorded at
each of 3 time periods (15-minute intervals) or at 1
time period on 3 separate days. Mean values for each
set of 5 trials and actual, normalized, and relative COP
variables were calculated. The reliability was quantified
by use of agreement boundary.

Results—The COP results within and across days
were similar and provided small agreement boundary
limits (eg, across days, in order of least relative reliability:
area, ± 62 mm2; mediolateral range, ± 8 mm;
radius, ± 2 mm; craniocaudal range, ± 4 mm; and
velocity, ± 3 mm/s). Head height possessed the greatest
relative intraday reliability (12%) but a high agreement
boundary limit (± 0.15 m).

Conclusions and Clinical Relevance—The use of a
force platform to analyze postural sway in a group of
young healthy horses was found to produce reliable
results and may provide a simple and sensitive measure
for assessing balance deficiencies in horses.
Agreement boundaries provide 95% confidence intervals
for use as limits of error and variability in measurements
that, if exceeded, may signify meaningful
effects. (Am J Vet Res 2003;64:1354–1359)
Evaluation of activated neutrophils in the blood of horses with colic
Authors: Weiss Douglas J. , Evanson Oral A.
Published: January 2006

Objective—To evaluate the activation status of neutrophils in blood samples obtained from horses with naturally occurring colic associated with strangulating obstruction, nonstrangulating obstruction, or inflammatory bowel disease.

Animals—30 horses with naturally occurring colic and 30 healthy control horses.

Procedure—Activation status of neutrophils was determined by assessing the number of neutrophils that could pass through filters with 5-µm pores, cellsurface CD11-CD18 expression, and alterations in size and granularity of neutrophils.

Results—Horses with impaction or gas colic did not have evidence of activated neutrophils. Horses with inflammatory bowel disease consistently had evidence of activated neutrophils, including decreased leukocyte deformability, increased CD11-CD18 expression, increased neutrophil size, and decreased neutrophil granularity. Horses with strangulating colic had variable results. Of horses with strangulating colic, 7 of 14 had marked changes in filtration pressures, 5 of 14 had increased CD11-CD18 expression, 6 of 14 had changes in neutrophil size, and 5 of 14 had changes in neutrophil granularity. Among horses with strangulating colic, changes in deformability, size, and granularity of neutrophils correlated with an adverse outcome.

Conclusions and Clinical Relevance—Activated neutrophils were detected in all horses with inflammatory bowel disease and a few horses with strangulating colic. Correlation of activated neutrophils with horses that had strangulating colic that died or were euthanatized indicates that activated neutrophils are a negative prognostic indicator. Additional studies are needed to determine whether activated neutrophils contribute directly to the adverse outcome in horses with strangulating colic. (Am J Vet Res2003;64:1364–1368)
Effect of darglitazone on glucose clearance and lipid metabolism in obese cats
Authors: Hoenig Margarethe , Ferguson Duncan C.
Published: January 2006

Objective—To examine the effect of darglitazone, a compound of the thiazolidinedione class, on glucose clearance and lipid metabolism in obese cats.

Animals—18 obese and 4 lean adult neutered female cats.

Procedure—IV glucose tolerance tests with measurements of glucose, insulin, and nonesterified fatty acid (NEFA) concentrations were performed before and 42 days after daily administration of darglitazone (9 obese cats) or placebo (9 obese and 4 lean cats). Additionally, cholesterol, triglyceride, leptin, and glycosylated hemoglobin concentrations were measured.

Results—Darglitazone-treated cats had significantly lower cholesterol, triglyceride, and leptin concentrations, compared with placebo-treated obese cats. A significant decrease in the area under the curve for NEFAs, glucose, and insulin during an IV glucose tolerance test was seen in darglitazone-treated cats. The drug was well tolerated.

Conclusions and Clinical Relevance—The response of obese cats to darglitazone was similar to the response to thiazolidinediones in obese humans and rodents Darglitazone was effective in improving insulin sensitivity and glucose and lipid metabolism in obese cats. (Am J Vet Res2003;64:1409–1413)
Use of the impulse oscillometry system for testing pulmonary function during methacholine bronchoprovocation in horses
Authors: Erck Emmanuelle van , Votion Dominique M. , Kirschvink Nathalie , Art Tatiana , Lekeux Pierre
Published: January 2006

Objective—To compare sensitivity of the impulse oscillometry system (IOS) with that of the conventional reference technique (CRT; ie, esophageal balloon method) for pulmonary function testing in horses.

Animals—10 horses (4 healthy; 6 with recurrent airway obstruction [heaves] in remission).

Procedure—Healthy horses (group-A horses) and heaves-affected horses (group-B horses) were housed in a controlled environment. At each step of a methacholine bronchoprovocation test, threshold concentration (TC2SD; results in a 2-fold increase in SD of a value) and sensitivity index (SI) were determined for respiratory tract system resistance (Rrs) and respiratory tract system reactance (Xrs) at 5 to 20 Hz by use of IOS and for total pulmonary resistance (RL) and dynamic lung compliance (Cdyn), by use of CRT.

Results—Bronchoconstriction resulted in an increase in Rrsat 5 Hz (R5Hz) and a decrease in Xrsat all frequencies. Most sensitive parameters were Xrsat 5 Hz (X5Hz), R5Hz, and R5Hz:R10Hzratio; RLand the provocation concentration of methacholine resulting in a 35% decrease in dynamic compliance (PC35Cdyn) were significantly less sensitive than these IOS parameters. The TC2SDfor Xrsat 5 and 10 Hz was significantly lower in group-B horses, compared with group-A horses. The lowest TC2SDwas obtained for X5Hzin group-B horses and R5Hzin group-A horses.

Conclusions and Clinical Relevance—In contrast to CRT parameters, IOS parameters were significantly more sensitive for testing pulmonary function. The IOS provides a practical and noninvasive pulmonary function test that may be useful in assessing subclinical changes in horses. (Am J Vet Res2003;64:1414–1420)
Detection of novel chlamydiae in cats with ocular disease
Authors: von Bomhard Wolf , Polkinghorne Adam , Huat Lu Zen , Vaughan Lloyd , Vögtlin Andrea , Zimmermann Dieter R. , Spiess Bernhard , Pospischil Andreas
Published: January 2006

Objective—To detect and characterize the full range of chlamydial infections in cats with ocular disease by use of polymerase chain reaction (PCR) assays, cytologic examination, immunohistochemical analysis, and evaluation of clinical information including status for feline herpesvirus-1 (FeHV-1).

Sample Population—DNA extracted from 226 conjunctival samples obtained from cats with clinically diagnosed keratitis or conjunctivitis and 30 conjunctival samples from healthy cats.

Procedure—PCR assays for the 16S rRNA gene specific for the order Chlamydiales and a newChlamydophila felis(formerlyChlamydia psittaci) species-specific 23S rRNA gene were performed. Seventy-four conjunctival samples were prepared with Romanowsky-type stain, grouped on the basis of inflammatory pattern, and screened for chlamydial inclusions by use of immunohistochemical analysis. Clinical information and FeHV-1 status were recorded.

Results—26 (12%) specimens had positive results for the only known feline chlamydial pathogen,C felis. Surprisingly, an additional 88 (39%) were positive for non-C felischlamydial DNA. Identification of non-C felischlamydial DNA by direct sequencing revealed 16S rRNA gene sequences that were 99% homologous to the sequence forNeochlamydia hartmannellae, an amebic endosymbiont. Chlamydial prevalence was significantly higher in cats with ocular disease.

Conclusions and Clinical Relevance—Application of a broad-range detection method resulted in identification of a new agent associated with ocular disease in cats. Finding chlamydia-like agents such asN hartmannellaein coinfections with their obligate amebic host,Hartmannella vermiformis, raises questions about the potential role of these microorganisms in causation or exacerbation of ocular disease in cats. (Am J Vet Res2003;64:1421–1428)
Characterization and comparison of the responses of equine digital arteries and veins to endothelin-1
Authors: Katz Lisa M. , Marr Celia M. , Elliott Jonathan
Published: January 2006

Objective—To compare the responses of equine digital arteries (EDAs) and equine digital veins (EDVs) to endothelin-1 (ET-1) and determine the role of the endothelium and type of receptors involved in the modulation and mediation of those responses, respectively.

Sample Population—5 to 9 palmar digital vessels/experiment from 28 healthy horses.

Procedure—Rings of dissected vessels were mounted under tension between force transducer wires in organ baths containing Krebs-Henseleit solution at 30oC. Responses of EDAs and EDVs (with intact [+e] or denuded [–e] endothelium) to cumulative concentrations of ET-1 (10–10to 3 × 10–7M) were compared. For (+e)EDAs and (+e)EDVs precontracted with a thromboxane-mimetic (U44069; 10–8M) and (–e)EDAs and (–e)EDVs, responses to an ETBreceptor agonist (S6c; 10–10to 3 × 10–7 M) were evaluated. Responses to ET-1 (10–7M) in (–e)EDAs and (–e)EDVs were evaluated after incubation with an ETAreceptor antagonist (BQ- 123; 3 × 10–7M), an ETBreceptor antagonist (BQ-788; 3 × 10–7M), or vehicle solution.

Results—Endothelin-1 induced a concentrationdependent contraction of endothelium-intact and -denuded EDAs and EDVs; EDVs were more sensitive. Neither vessel type relaxed in response to S6c, although 2 of the (–e)EDAs contracted mildly. Whereas BQ-123 inhibited the (–e)EDA and (–e)EDV responses to ET-1, BQ-788 had no effect.

Conclusions and Clinical Relevance—Endothelin-1 induced digital vasoconstriction (marked constriction in veins). This action was unaffected by endothelium and mediated predominantly by ETAreceptors. These findings suggest ET-1 can induce selective digital venoconstriction. (Am J Vet Res2003;64:1438–1443
Effects of duration of isoflurane anesthesia and mode of ventilation on intracranial and cerebral perfusion pressures in horses
Authors: Brosnan Robert J. , Steffey Eugene P. , LeCouteur Richard A. , Farver Thomas B. , Imai Ayako
Published: January 2006

Objective—To test the hypothesis that isofluraneanesthetized horses during controlled ventilation and spontaneous ventilation exhibit temporal changes in cerebral hemodynamics, as measured by intracranial pressure and cerebral perfusion pressure, that reflect temporal changes in systemic arterial pressure.

Animals—6 healthy adult horses.

Procedure—Horses were anesthetized in left lateral recumbency with 1.57% isoflurane in O2for 5 hours in 2 experiments by use of either controlled ventilation (with normocapnia) or spontaneous ventilation (with hypercapnia) in a randomized crossover design. Intracranial pressure was measured with a subarachnoid strain-gauge transducer. Carotid artery pressure, central venous pressure, airway pressures, blood gases, and minute ventilation also were measured.

Results—Intracranial pressure during controlled ventilation significantly increased during constant dose isoflurane anesthesia and thus contributed to decreasing cerebral perfusion pressure. Intracranial pressure was initially higher during spontaneous ventilation than during controlled ventilation, but this difference disappeared over time; no significant differences in cerebral perfusion pressures were observed between horses that had spontaneous or controlled ventilation.

Conclusions and Clinical Relevance—Cerebral hemodynamics and their association with ventilation mode are altered over time in isoflurane-anesthetized horses and could contribute to decreased cerebral perfusion during prolonged anesthesia. (Am J Vet Res2003;64:1444–1448)
Spectral analysis of heart rate variability in dogs with mild mitral regurgitation
Authors: Fujii Yoko , Wakao Yoshito
Published: January 2006

Objective—To assess autonomic function in dogs with mild mitral regurgitation (MR) that did not have clinical signs of the condition.

Animals—6 healthy adult Beagles.

Procedure—Mild MR was experimentally induced. A 24-hour ambulatory ECG was recorded before and after induction of MR. Heart rate variability was analyzed in frequency domains by use of the ambulatory ECG. Low-frequency (LF) and high-frequency (HF) power were calculated by integrating over their frequency intervals, and the ratio of LF to HF was also calculated. Measurements of frequency domains were analyzed for 4 time periods (midnight to 6 AM, 6 AM to noon, noon to 6 PM, and 6 PM to midnight).

Results—Dogs with experimentally induced MR were classified as International Small Animal Cardiac Health Council class Ia. The HF power of dogs with MR was significantly decreased between 6 AM and noon. The ratio of LF to HF in dogs with MR was significantly increased for the periods between midnight and 6 AM, 6 AM and noon, and noon and 6 PM.

Conclusions and Clinical Relevance—Compensatory response through autonomic modulation was observed in dogs with mild MR that did not have abnormalities, except for cardiac murmur, during clinical examination. This result suggests that treatment during the early stages of mild MR may be beneficial. Additional studies are necessary to determine whether such treatment will delay the onset of congestive heart failure and prolong survival in dogs affected with mild MR. (Am J Vet Res2003; 64:145–148)
Detection of biofilm formation and nanobacteria under long-term cell culture conditions in serum samples of cattle, goats, cats, and dogs
Authors: Barr Stephen C. , Linke Rebecca A. , Janssen Dorothee , Guard Charles L. , Smith Mary C. , Daugherty Carole S. , Scarlett Janet M.
Published: January 2006

Objective—To determine the prevalence of biofilm
formation under long-term cell culture conditions in
serum samples of dairy cattle, goats, cats, and dogs,
and to determine whether there is an association
between nanobacteria and biofilm formation.

Sample Population—Serum samples of clinically
normal animals (313 dairy cattle, 48 goats, 140 dogs,
and 44 cats) and animals with various medical conditions
(60 dogs and 116 cats).

Procedure—Serum was incubated under cell culture
conditions and observed for biofilm formation by use
of light microscopy, electron microscopy, and spectroscopy.
A polymerase chain reaction assay was
developed to identify 16S rRNA gene sequences of
nanobacteria.

Results—Biofilm formation developed in serum samples
of 304 of 313 (97%) cattle, 44 of 48 (92%) goats,
44 of 44 (100%) cats, and 126 of 140 (90%) dogs.
Prevalence of serum samples with positive results for
biofilm formation was not significantly different
between cats or dogs with and without medical conditions
associated with pathologic extraskeletal calcification
processes. Scanning electron microscopy and
spectroscopy of biofilm samples revealed small coccoid
particles consisting mainly of calcium and phosphate.
Polymerase chain reaction assay failed to
amplify sequences of nanobacteria.

Conclusions and Clinical Relevance—Under longterm
cell culture conditions, biofilm made up of aggregates
of calcium and phosphate crystals does form in
serum samples of clinically normal dairy cattle, goats,
cats, and dogs. Disease, however, does not predispose
to biofilm formation in serum samples of dogs
and cats. Our findings did not support the existence
of nanobacteria in serum samples of cattle, goats,
cats, and dogs. (Am J Vet Res 2003;64:176–182)
Use of threshold serum and milk ketone concentrations to identify risk for ketosis and endometritis in high-yielding dairy cows
Authors: Reist Martin , Erdin Daniel K. , von Euw Daniel , Tschümperlin Kaspar M. , Leuenberger Hans , Hammon Harald M. , Künzi Niklaus , Blum Jürg W.
Published: January 2006

Objective—To use threshold concentrations of acetone and β-hydroxybutyrate in milk and serum, respectively; identify risk for ketosis and endometritis; and assess analyses of blood and milk samples as predictors of risk for ketosis in high-yielding dairy cows.

Animals—90 multiparous Holstein cows.

Procedure—At intervals before and after parturition, blood samples were obtained for determination of glucose, nonesterified fatty acids, leptin, insulin, insulin-like growth factor-1, and β-hydroxybutyrate concentrations. Samples of milk were obtained at similar intervals after parturition for determination of fat content and concentrations of acetone, protein, and lactose. Reproductive examination of each cow was performed weekly.

Results—For each cow, threshold concentrations of acetone and β-hydroxybutyrate were calculated as 75th and 90th percentiles of maximum postpartum concentrations of acetone in milk (0.40 and 0.87 mmol/L) and β-hydroxybutyrate in serum (2.30 and 3.51 mmol/L). Significant decrease in milk production (442 to 654 kg of energy-corrected milk/305-day period per cow) was associated with acetone or β-hydroxybutyrate in excess of threshold values. Milk acetone concentrations > 0.40 mmol/L were associated with 3.2 times higher risk for endometritis. Low plasma glucose, high serum β-hydroxybutyrate, and high milk acetone concentrations during week 1 after parturition were indicators of increased risk for ketosis later during lactation.

Conclusions and Clinical Relevance—Determination of milk acetone concentration during the week after parturition may identify cows at risk for ketosis and endometritis; with appropriate interventions, development of disease and production losses may be reduced. (Am J Vet Res2003:64:188–194)
Description of an epidemic simulation model for use in evaluating strategies to control an outbreak of foot-and-mouth disease
Authors: Bates Thomas W. , Thurmond Mark C. , Carpenter Tim E.
Published: January 2006

Objective—To develop a spatial epidemic model to
simulate intraherd and interherd transmission of footand-
mouth disease (FMD) virus.

Sample Population—2,238 herds, representing
beef, dairy, swine, goats, and sheep, and 5 sale yards
located in Fresno, Kings, and Tulare counties of
California.

Procedure—Using Monte-Carlo simulations, a spatial
stochastic epidemic simulation model was developed
to identify new herds that would acquire FMD following
random selection of an index herd and to assess
progression of an epidemic after implementation of
mandatory control strategies.

Results—The model included species-specific transition
periods for FMD infection, locations of herds,
rates of direct and indirect contacts among herds, and
probability distributions derived from expert opinions
on probabilities of transmission by direct and indirect
contact, as well as reduction in contact following
implementation of restrictions on movements in designated
infected areas and surveillance zones.
Models of supplemental control programs included
slaughter of all animals within a specified distance of
infected herds, slaughter of only high-risk animals
identified by use of a model simulation, and vaccination
of all animals within a 5- to 50-km radius of infected
herds.

Conclusions and Clinical Relevance—The FMD
model represents a tool for use in planning biosecurity
and emergency-response programs and in comparing
potential benefits of various strategies for control
and eradication of FMD appropriate for specific populations.
(Am J Vet Res 2003;64:195–204)
Diagnostic value of the use of lateral and occlusal radiographic views in comparison with periodontal probing for the assessment of periodontal attachment of the canine teeth in dogs
Authors: Tsugawa Anson J. , Verstraete Frank J. M. , Kass Philip H. , Görrel Cecilia
Published: January 2006

Objective—To determine the diagnostic value of 2 intraoral bisecting angle radiographic views in comparison with periodontal probing for the assessment of periodontal attachment of the canine teeth in dogs.

Study Population—466 canine teeth from 117 dogs.

Procedure—Periodontal probing measurements were recorded, and clinical attachment levels (CAL) were calculated at the mesial, buccal, distal, and lingual (or palatal) surfaces on each canine tooth. Occlusal and lateral radiographs of the canine teeth were obtained. Alveolar margin height (AMH) was measured at the same 4 surfaces. Values for AMH and CAL were compared on the basis of tooth surface, dental arch, and radiographic view.

Results—The AMH at the mesial and distal surfaces of the mandibular canine teeth was measurable on the lateral view and was significantly correlated with CAL. Similar results were found for the mesial and distal surfaces of the maxillary canine teeth. Buccal and lingual AMH were measured on the mandibular occlusal radiographic view, and values were significantly correlated with CAL, but only the buccal AMH could be assessed on the occlusal radiographic view of the maxilla with values that correlated significantly with CAL.

Conclusions and Clinical Relevance—The lateral radiographic view is suitable for evaluating periodontal attachment at the mesial and distal surfaces of the canine teeth in dogs. The occlusal radiographic view is suitable for assessing buccal surfaces as well as the lingual surface of mandibular canine teeth but not the palatal surface of maxillary canine teeth in dogs. (Am J Vet Res2003;64:255–261)
Relationship of age, sex, body weight, and hematologic and respiratory variables with airway reactivity in adult cats
Authors: Hirt Reinhard A. , Dederichs Diana , Boehler Alexandra , Hoffman Andrew M.
Published: January 2006

Objective—To evaluate the association between airway reactivity and age, sex, body weight, and radiographic findings in cats.

Animals—32 mature cats that constituted 2 age groups (17 young cats that were 1 to 2 years old and 15 old cats that were 12 to 13 years old).

Procedure—Cats were placed in the chamber of a barometric whole-body plethysmograph (volume, 38 L), and box pressure was measured at baseline and after aerosol administration of increasing concentrations of carbachol. Airway reactivity was assessed by monitoring increases in enhanced pause (PENH), a unitless variable that measures bronchoconstriction as derived from dose-response curves. The endpoint chosen was the provocative concentration of carbachol that increased PENH to 300% of the baseline value (PCPENH300).

Results—We did not find a correlation between PCPENH300 and sex, body weight, number of eosinophils, PENH before bronchoconstriction, respiratory frequency, tidal volume, or minute ventilation. Airway reactivity was significantly less in the old cats (mean ± SD PCPENH300, 0.578 ± 0.051%), compared with the value for the young cats (0.053 ± 0.006%). Radiographic patterns differed significantly between groups of cats; a greater proportion of old cats (12/15) had bronchointerstitial patterns, compared with the proportion of young cats (4/17).

Conclusion and Clinical Relevance—These data support the notion that age exerts a strong influence on airway reactivity in adult cats, and radiographic differences suggest that structural changes in older cats may contribute to this effect. These findings have important implications for interpretation of results of airway reactivity tests in cats. (Am J Vet Res2003;64:26–31)
Expression of the ether-a-go-go (ERG) potassium channel in smooth muscle of the equine gastrointestinal tract and influence on activity of jejunal smooth muscle
Authors: Lillich James D. , Rakestraw Peter C. , Roussel Allen J. , Finley Melissa R. , Ganta Suhasini , Freeman Lisa C.
Published: January 2006

Objective—To determine whether ether-a-go-go (ERG) potassium channels are expressed in equine gastrointestinal smooth muscle, whether ERG channel antagonists affect jejunal muscle contraction in vitro, and whether plasma cisapride concentrations in horses administered treatment for postoperative ileus (POI) are consistent with ERG channels as drug targets.

Sample Population—Samples of intestinal smooth muscle obtained from 8 horses free of gastrointestinal tract disease and plasma samples obtained from 3 horses administered cisapride for treatment of POI.

Procedure—Membranes were prepared from the seromuscular layer of the duodenum, jejunum, ileum, cecum, large colon, and small colon. Immunoblotting was used to identify the ERG channel protein. Isolated jejunal muscle strips were used for isometric stress response to ERG channel blockers that included E-4031, MK-499, clofilium, and cisapride. Plasma concentrations of cisapride were determined in 3 horses administered cisapride for treatment of POI after small intestinal surgery.

Results—Immunoblotting identified ERG protein in all analyzed segments of the intestinal tract in all horses. The selective ERG antagonist E-4031 caused a concentration- dependent increase in jejunal contraction. Clofilium, MK-499, and cisapride also increased jejunal contraction at concentrations consistent with ERG channel block; effects of E-4031 and cisapride were not additive. Peak plasma cisapride concentrations in treated horses were consistent with ERG block as a mechanism of drug action.

Conclusions and Clinical Relevance—The ERG potassium channels modulate motility of intestinal muscles in horses and may be a target for drugs. This finding may influence development of new prokinetic agents and impact treatment of horses with POI. (Am J Vet Res2003;64:267–272)