bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of viral ribonucleic acid in plasma of cats naturally infected with feline immunodeficiency virus
Authors: Goto Yuko , Nishimura Yoshiaki , Mizuno Takuya , Endo Yasuyuki , Baba Kenji , Momoi Yasuyuki , Watari Toshihiro , Hasegawa Atsuhiko , Tsujimoto Hajime
Published: December 2005

Objective—To assess plasma viral RNA concentration
in cats naturally infected with feline immunodeficiency
virus (FIV).

Animals—28 FIV-infected cats.

Procedure—Cats were categorized into 1 of the 3 following
stages on the basis of clinical signs: asymptomatic
(nonclinical) carrier (AC; n = 11), acquired
immunodeficiency syndrome-related complex (ARC;
9), or acquired immunodeficiency syndrome (AIDS;
8). Concentration of viral RNA in plasma (copies per
ml) was determined by use of a quantitative competitive
polymerase chain reaction (QC-PCR) assay. Total
lymphocyte count, CD4+ cell and CD8+ cell counts,
and the CD4+ cell count-to-CD8+ cell count ratio were
determined by use of flow cytometry.

Results—Plasma viral RNA concentration was significantly
higher in cats in the AIDS stage, compared
with cats in AC and ARC stages. Most (5/7) cats in the
AIDS stage had low total lymphocyte, CD4+ cell, and
CD8+ cell counts.

Conclusions and Clinical Relevance—Concentration
of plasma viral RNA is a good indicator of disease progression
in FIV-infected cats, particularly as cats
progress from the ARC to the AIDS stage.
Determination of CD4+ and CD8+ cell counts can be
used as supportive indicators of disease progression.
(Am J Vet Res 2000;61:1609–1613)
Antigenic and molecular characterization of a herpesvirus isolated from a North American elk
Authors: Deregt Dirk , Jordan Lorne T. , Hurk Sylvia van Drunen Littel-van den , Masri Saad A. , Tessaro Stacy V. , Gilbert Scott A.
Published: December 2005

Objective—To determine whether a herpesvirus isolated
from the semen of a North American elk was
related to bovine herpesvirus 1 (BHV-1).

Sample Population—Semen from 1 healthy bull elk
and 2 subtypes of BHV-1 (BHV-1.1 and BHV-1.2).

Procedures—A virus with cytopathic and electron
microscopic characteristics consistent with an alphaherpesvirus
was isolated from elk semen, using fetal
bovine kidney cells. Cross-neutralization assays were
performed with antisera against BHV-1 and the elk
herpesvirus (ElkHV). Restriction endonuclease
digests of ElkHV DNA were compared with digests of
BHV-1.1 and BHV-1.2 DNA. A portion of the ElkHV
DNA polymerase gene was amplified with consensus
primers by use of the polymerase chain reaction and
sequenced. Sequence was compared with known
sequences of other herpesviruses. An immunoperoxidase
monolayer assay was used to determine reactivities
of 22 BHV–1-specific monoclonal antibodies
(mAb) against ElkHV. In vitro neutralizing activities of
the reactive mAb were determined by use of a
microneutralization assay.

Results—Results of cross-neutralization assays indicated
that ElkHV was serologically related to BHV-1.
Endonuclease digestion of ElkHV DNA generated
fragments that were distinct from those of BHV-1.
Nucleotide sequencing confirmed that ElkHV is an
alphaherpesvirus closely related to but distinct from
BHV-1. Six of 22 BHV–1-specific mAb reacted against
ElkHV; 2 of these 6 also neutralized in vitro infectivity
of ElkHV.

Conclusions and Clinical Relevance—ElkHV is antigenically
and genetically distinguishable from BHV-1.
However, the viruses are serologically related and
share at least 6 antigenic determinants, one of which
is a major neutralizing determinant. (Am J Vet Res
2000;61:1614–1618)
In vitro comparison of transfixation and standard full-limb casts for prevention of displacement of a mid-diaphyseal third metacarpal osteotomy site in horses
Authors: Hopper Scott A. , Schneider Robert K. , Johnson Craig H. , Ratzlaff Marc H. , White Karl K.
Published: December 2005

Objective—–To compare transfixation and standard full-limb casts for prevention of in vitro displacement of a mid-diaphyseal third metacarpal osteotomy site in horses.

Sample Population—6 forelimbs from 6 horses euthanatized for reasons not related to the musculoskeletal system.

Procedure—A 30° osteotomy was performed in the mid-diaphysis of the third metacarpal bone. Two 4.5-mm cortical bone screws were placed across the osteotomy site to maintain alignment during casting. Two 6.35-mm Steinmann pins were placed from a lateral-to-medial direction in the distal aspect of the radius. A full-limb cast that incorporated the pins was applied. An extensometer was positioned in the osteotomy site through a window placed in the dorsal aspect of the cast, and after removal of the screws, displacement was recorded while the limb was axially loaded to 5,340 N (1,200 lb). Pins were removed, and the standard full-limb cast was tested in a similar fashion.

Results—The transfixation cast significantly reduced displacement across the osteotomy site at 445 N (100 lb), 1,112 N (250 lb), 2,224 N (500 lb), and 4,448 N (1,000 lb), compared with the standard cast.

Conclusion and Clinical Relevance—A full-limb transfixation cast provides significantly greater resistance than a standard full-limb cast against axial collapse of a mid-diaphyseal third metacarpal osteotomy site when the bone is placed under axial compression. Placement of full-limb transfixation casts should be considered for the management of unstable fractures of the third metacarpal bone in horses. (Am J Vet Res2000;61:1633–1635)
Ultrastructural changes in follicles of small-intestinal aggregated lymphoid nodules in early and advanced phases of experimentally induced mucosal disease in calves
Authors: Teichmann Ulrike , Liebler-Tenorio Elisabeth M. , Pohlenz Joachim F.
Published: December 2005

Objective—To investigate ultrastructural changes in follicles of small-intestinal aggregated lymphoid nodules (Peyer's patches) of calves with early and advanced phases of experimentally induced mucosal disease (MD).

Animals—Twenty 2.5- to 7-month-old Holstein-Friesian calves (11 females, 9 males).

Procedure—MD was induced in 13 of 18 calves that were persistently viremic with bovine viral diarrhea virus (BVDV). Eight of the 13 calves were euthanatized before the onset of clinical signs of MD, and 5 were euthanatized after becoming moribund with MD. Five persistently viremic calves and 2 calves without BVDV served as controls. Specimens of small-intestinal aggregated lymphoid nodules were prepared for transmission electron microscopy.

Results—The ultrastructure of follicles of smallintestinal aggregated lymphoid nodules from healthy calves was consistent with that in sheep. In the early phase of MD, changes were characterized by numerous apoptotic lymphocytes and macrophages with apoptotic bodies. In more advanced lesions, affected lymphoid follicles consisted of macrophages and variable numbers of follicular dendritic cells (FDC), whereas others did not contain FDC. In moribund calves, small follicles consisting predominantly of FDC and follicles with central cavities surrounded by macrophages, and few neutrophils were observed.

Conclusions and Clinical Relevance—The ultrastructural changes in lymphoid follicles of smallintestinal aggregated lymphoid nodules indicate apoptosis of lymphocytes as an initial event. The development of small follicles consisting predominantly of FDC or the complete loss of follicular architecture in advanced phases of MD is determined by the intensity of apoptosis of lymphocytes, the capacity of the macrophages for uptake, and the reorganization of a stromal network. (Am J Vet Res2000;61:174–182)
Structure-related echoes in ultrasonographic images of equine superficial digital flexor tendons
Authors: Schie Hans T. M. van , Bakker E. M.
Published: December 2005

Objective—To develop a method to discriminate between structure-related echoes and echoes resulting from interference, as observed in transverse ultrasonographic images of equine superficial digital flexor (SDF) tendons.

Sample Population—2 normal (injury-free) SDF tendons obtained from a 3-year-old Thoroughbred and a 9-year-old Dutch Warmblood horse.

Procedure—Tendons were mounted in a custommade device that permitted exact transverse and perpendicular sequential scanning with precise steps of 0.5 mm along the long axis of the tendon. Photographs of ultrasonographic images of transverse tendon sections at the exact scanning locations were obtained. Propagation, reflection, and refraction artifacts were quantified, and an image rectification procedure was developed, allowing exact matching of each photograph with the corresponding ultrasonographic image. A correlation routine was developed that departed from this transverse ultrasonographic image (position 0); this routine added information from images collected at precise distances of 0.5 and 1 mm on both sides of the actual scan location (positions –2, –1, +1, +2).

Results—By use of the correlation routine, echoes that remained steady over all 5 images were enhanced and resolved, and constantly changing echoes were multiplicatively reduced and faded. This correlated image could be projected over the rectified photograph, and the resolved echoes matched perfectly with the endotendon septa surrounding fibers and fasciculi.

Conclusions and Clinical Relevance—The correlation routine permits exclusive resolution of structurerelated echoes, as echoes resulting from interference are faded. The technique described can produce images that depict only the essential structure-related information. In this way, the clinical assessment of tendon integrity is greatly facilitated. (Am J Vet Res1999;60:202–209)
Ultrasonographic tissue characterization of equine superficial digital flexor tendons by means of gray level statistics
Authors: Schie Hans T. M. van , Bakker E. M. , Jonker A. M. , Weeren P. R. van
Published: December 2005

Objective—To correlate quantitative analysis of ultrasonographic images of normal (injury-free) equine superficial digital flexor (SDF) tendons and equine SFD tendons that have pathologic changes with corresponding histologic sections.

Sample Population—4 SDF tendons, 2 of which had various stages of tissue integrity. The 2 ipsilateral tendons were used as points of reference.

Procedure—Tendons were mounted in a custommade device that permitted sequential scanning, transversely and perpendicular to the tendon long axis. At precise steps of 0.5 mm, transverse ultrasonographic images were collected. Subsequently, tendons were fixed and prepared for histologic examination. The following 8 tissue types were discerned: normal young, normal old, necrotic, early granulation, late granulation, early fibrotic, late fibrotic, and scar tissues. In areas of interest, the corresponding ultrasonographic images were selected for gray level statistical analysis.

Results—Compared with other tissue types, earlystage granulation tissue was characterized by substantially lower mean gray level and a clearly different histogram. Necrotic tissue had a higher mean gray level, with a virtually normal histogram. In late granulation and early fibrotic tissues, the mean gray level and the histogram could not be discerned from those of normal tendon tissue. The same applied to late fibrotic and scar tissues; mean gray levels were fractionally lower than those of normal tendon tissue with a completely normal histogram.

Conclusions—Although quantification of the transverse ultrasonographic image by use of first-order gray level statistics may be helpful, the method is not sufficiently sensitive to accurately and unequivocally determine the type of tendon tissue. Quantitative analysis should incorporate transverse and longitudinal information. (Am J Vet Res2000;61: 210–219)
Calcium regulation by skeletal muscle membranes of horses with recurrent exertional rhabdomyolysis
Authors: Ward Tara L. , Valberg Stephanie J. , Gallant Esther M. , Mickelson James R.
Published: December 2005

Objective—To determine whether an alteration in calcium regulation by skeletal muscle sarcoplasmic reticulum, similar to known defects that cause malignant hyperthermia (MH), could be identified in membrane vesicles isolated from the muscles of Thoroughbreds with recurrent exertional rhabdomyolysis (RER).

Sample Population—Muscle biopsy specimens from 6 Thoroughbreds with RER and 6 healthy (control) horses.

Procedures—RER was diagnosed on the basis of a history of > 3 episodes of exertional rhabdomyolysis confirmed by increases in serum creatine kinase (CK) activity. Skeletal muscle membrane vesicles, prepared by differential centrifugation of muscle tissue homogenates obtained from the horses, were characterized for sarcoplasmic reticulum (SR) activities, including the Ca2+release rate for the ryanodine receptor-Ca2+release channel, [3H]ryanodine binding activities, and rate of SR Ca2+-ATPase activity and its activation by Ca2+.

Results—Time course of SR Ca2+-induced Ca2+release and [3H]ryanodine binding to the ryanodine receptor after incubation with varying concentrations of ryanodine, caffeine, and ionized calcium did not differ between muscle membranes obtained from control and RER horses. Furthermore, the maximal rate of SR Ca2+-ATPase activity and its affinity for Ca2+did not differ between muscle membranes from control horses and horses with RER.

Conclusions and Clinical Relevance—Despite clinical and physiologic similarities between RER and MH, we concluded that RER in Thoroughbreds does not resemble the SR ryanodine receptor defect responsible for MH and may represent a novel defect in muscle excitation-contraction coupling, calcium regulation, or contractility. (Am J Vet Res2000;61:242–247)
Respiratory reflexes in response to nasal administration of halothane to anesthetized, spontaneously breathing dogs
Authors: Mutoh Tatsushi , Kanamaru Arata , Tsubone Hirokazu , Nishimura Ryohei , Sasaki Nobuo
Published: December 2005

Objective—To characterize and determine the sensory innervation of respiratory reflexes elicited by nasal administration of halothane to dogs.

Animals—10 healthy Beagles.

Procedure—Dogs underwent permanent tracheostomy and, 2 to 3 weeks later, were anesthetized with thiopental and α-chloralose administered IV. The nasal passages were functionally isolated so that halothane could be administered to the nasal passages while dogs were breathing 100% O2via the tracheostomy. Respiratory reflexes in response to administration of halothane at concentrations of 1.25, 1.75, and 2.5 times the minimum alveolar concentration (MAC), and 5% (administered in 100% O2at a flow rate of 5 L/min) were recorded. Reflexes in response to administration of 5% halothane were also recorded following transection of the infraorbital nerve, transection of the caudal nasal nerve, and nasal administration of lidocaine.

Results—Nasal administration of halothane induced an inhibition of breathing characterized by a dosedependent increase in expiratory time and a resultant decrease in expired volume per unit time. Effects were noticeable immediately after the onset of halothane administration and lasted until its cessation. Reflex responses to halothane administration were attenuated by transection of the caudal nasal nerve and by nasal administration of lidocaine, but transection of the infraorbital nerve had no effect.

Conclusions and Clinical Relevance—Nasal administration of halothane at concentrations generally used for mask induction of anesthesia induces reflex inhibition of breathing. Afferent fibers in the caudal nasal nerve appear to play an important role in the reflex inhibition of breathing induced by halothane administration. (Am J Vet Res2000;61:260–267)
Histomorphometric analysis of the proximal portion of the femur in healthy dogs
Authors: Edinger David T. , Hayashi Kei , Hongyu Yao , Markel Mark D. , Manley Paul A.
Published: December 2005

Objective—To describe the cancellous bone architecture
of the head and neck of the femur in healthy
dogs by use of automated histomorphometry techniques
in conjunction with histologic grading of articular
cartilage.

Animals—30 mature male dogs with healthy coxofemoral
joints

Procedure—Dogs were 1.5 to 4 years old and
weighed 27 to 37 kg. Computer images of fine-detail
radiographs of 100-µm-thick coronal and transverse
plane sections of the head and neck of the femur
(14 dogs) were analyzed by use of histomorphometry
software. Statistical comparisons among histomorphometric
indices of 4 regions were performed.
Histologic preparations of coronal and transverse
plane sections of femoral head articular cartilage
(16 dogs) were graded. Median grades for lateral,
medial, cranial, and caudal halves of the femoral head
articular cartilage were determined.

Results—Bone volume/total volume, trabecular thickness
and number, and bone surface/total volume were
significantly higher in the femoral head than in the
femoral neck. Anisotropy (trabecular alignment) and
trabecular separation were significantly higher in the
femoral neck than in the femoral head. Anisotropy was
significantly higher in the caudal half of the femoral
neck than in the cranial half. Cartilage had histologic
grades indicating health without significant differences
among lateral, medial, cranial, and caudal halves of
femoral head cartilage.

Conclusions and Clinical Relevance—A predictable
cancellous architecture in the head and neck of the
femur is associated with healthy cartilage. (Am J Vet
Res 2000;61:268–274)
Effect of sample number and time on determination of plasma clearance of technetium Tc 99m pentetate and orthoiodohippurate sodium I 131 in dogs and cats
Authors: Barthez Paul Y. , Chew Dennis J. , DiBartola Stephen P.
Published: December 2005

Objective—To determine the effect of number of blood samples and sampling times on plasma clearance of technetium Tc 99m pentetate (Tc99mP) and orthoiodohippurate sodium I 131(OIH).

Animals—20 dogs and 14 cats.

Procedure—Plasma clearances of OIH and Tc99mP were calculated by use of a 2-compartment model, on the basis of a 12-point curve as a reference method. Plasma clearance was calculated by use of all possible combinations of 4 to 11 samples. Time schedule yielding the smallest difference from the reference method was considered to be optimal. Regression analysis was performed between the 12-point model and models using a reduced number of samples.

Results—SD of the difference between the 12-point clearance and the models with reduced numbers of samples increased when the number of samples decreased. The SD of the difference between 12-point clearance and 4-point clearance was 4.17 ml/min for OIH and 0.94 ml/min for Tc99mP in dogs and 0.45 ml/min for OIH and 0.11 ml/min for Tc99mP in cats. Optimal schedules were distributed logarithmically and included an early sample at 5 or 10 minutes, a late sample at 2.5, 3, 4, or 5 hours for OIH, and a late sample at 4 or 5 hours for Tc99mP.

Conclusions and Clinical Relevance—Plasma clearances of OIH and Tc99mP can be accurately calculated in dogs and cats by use of a single-injection 2-compartment pharmacologic model with a reduced number of blood samples, resulting in an acceptable margin of error. (Am J Vet Res2000;61:280–285)
Comparison of nuclear scintigraphy and acetaminophen absorption as a means of studying gastric emptying in horses
Authors: Lohmann Katharina L. , Roussel Allen J. , Cohen Noah D. , Boothe Dawn M. , Rakestraw Peter C. , Walker Michael A.
Published: December 2005

Objective—To evaluate the correlation between halftime of liquid-phase gastric emptying (T50), determined with nuclear scintigraphy using technetium Tc 99m pentetate, and absorption variables of orally administered acetaminophen.

Animals—6 mature horses.

Procedure—Technetium Tc 99m pentetate (10 mCi) and acetaminophen (20 mg/kg of body weight) were administered simultaneously in 200 ml of water. Serial left and right lateral images of the stomach region were obtained with a gamma camera, and T50determined separately for counts obtained from the left side, the right side and the geometric mean. Power exponential curves were used for estimation of T50 and modified R2 values for estimation of goodness of fit of the data. Serial serum samples were taken, and acetaminophen concentration was determined, using fluorescence polarization immunoassay. Maximum serum concentration (Cmax), time to reach maximum serum concentration (Tmax), area under the curve for 240 minutes and the absorption constant (Ka) were determined, using a parameter estimation program. Correlations were calculated, using the Spearman rank correlation coefficient.

Results—Correlations between T50and Tmaxand between T50and Kawere significant.

Conclusions and Clinical Relevance—Tmaxand Kaare valuable variables in the assessment of liquidphase gastric emptying using acetaminophen absorption. Acetaminophen absorption may be a valuable alternative to nuclear scintigraphy in the determination of gastric emptying rates in equine patients with normally functioning small intestine. (Am J Vet Res2000;61:310–315)
Comparison of polymerase chain reaction assays with bacteriologic culture, immunofluorescence, and nucleic acid hybridization for detection of Leptospira borgpetersenii serovar hardjo in urine of cattle
Authors: Wagenaar Jaap , Zuerner Richard L. , Alt David , Bolin Carole A.
Published: December 2005

Objective—To compare sensitivity and specificity of various polymerase chain reaction (PCR) assays for detection ofLeptospira borgpeterseniiserovarhardjoin bovine urine and to compare results of the optimal PCR assay with results of immunofluorescence, nucleic acid hybridization, and bacteriologic culture.

Animals—6 heifers.

Procedure—Heifers were exposed to serovar hardjo type hardjo-bovis by conjunctival instillation of 106leptospires on 3 successive days. Urine samples were collected before and after infection. Sensitivity and specificity of 5 PCR assays were compared, to determine the optimal assay for use with bovine urine samples. The optimal PCR assay was then compared with results of bacteriologic culture, nucleic acid hybridization, and immunofluorescence.

Results—A PCR assay with the best combination of specificity (100%) and sensitivity (91%) was selected for comparison with the other diagnostic tests. Sensitivity for nucleic acid hybridization was 55%, whereas sensitivity for bacteriologic culture and immunofluorescence was 89 to 93%.

Conclusions and Clinical Relevance—Bacteriologic culture, PCR, and immunofluorescence were sensitive for detection ofL borgpeterseniiserovarhardjotype hardjo-bovis in urine specimens of cattle, but a single technique was not the most sensitive for each animal tested. Therefore, the use of 2 techniques in combination is warranted for maximal sensitivity for diagnosis. (Am J Vet Res2000;61:316–320)
Comparison of equine amnion and a nonadherent wound dressing material for bandaging pinch-grafted wounds in ponies
Authors: Goodrich Laurie R. , Moll H. David , Crisman Mark V. , Lessard Pierre , Bigbie Rocky B.
Published: December 2005

Objective—To evaluate healing of pinch-grafted wounds on the distal aspect of the limbs of ponies bandaged with equine amnion or a standard nonadherent wound dressing material.

Animals—6 ponies.

Procedure—A 2.5 × 2.5-cm full-thickness section of skin was removed from the dorsal aspect of each limb at the midpoint of the metacarpus or metatarsus. Six days later, wounds were grafted with partial-thickness pinch grafts. Half the wounds were bandaged with amnion, and the other half were bandaged with a nonadherent dressing. Bandages were changed every 3 days until wound healing was complete. At each bandage change, numbers of grafts lost were recorded, and wounds were measured.

Results—Percentage of grafts lost from wounds bandaged with amnion was not significantly different from percentage lost from wounds bandaged with the nonadherent dressing. Median healing time for wounds bandaged with amnion (30 days) was significantly less than median healing time for wounds bandaged with the nonadherent dressing (39 days). All wounds were healed by day 45.

Conclusions and Clinical Relevance—Results suggest that amnion can be used for bandaging pinchgrafted wounds on the distal aspect of the limbs of ponies. (Am J Vet Res2000;61:326–329)
Immune function of bovine leukocytes after in vitro exposure to selected heavy metals
Authors: Guise Sylvain De , Bernier Jacques , Lapierre Patrice , Dufresne Marc M. , Dubreuil Pascal , Fournier Michel
Published: December 2005

Objective—To study effects of in vitro exposure of
bovine leukocytes to mercury, cadmium, and lead on
phagocytosis, natural killer cell activity, and lymphocyte
proliferation.

Sample Population—Leukocytes from 6 nonpregnant
Holstein heifers.

Procedure—Leukocytes were exposed in vitro to the
aforementioned metals, and leukocyte functions
were assessed.

Results—Phagocytosis was suppressed by 10−5 to
10−7
M CdCl2 and by 10−5 and 10−6
M HgCl2, but not
10−7
M HgCl2 nor 10−4 to 10−6
M PbCl2. Spontaneous and
concanavalin A- or phytohemagglutinin-stimulated proliferation
of metal-treated bovine blood mononuclear
cells was not significantly different from that of nontreated
control cells, except for enhanced spontaneous
proliferation in response to 10−5
M HgCl2. When proliferation
was expressed as a stimulation index, a dosedependent
increase of spontaneous proliferation was
observed in response to exposure to HgCl2 and PbCl2.
Compared with response to 10−6 or 10−7
M CdCl2, reduction
of mitogen-induced and spontaneous proliferation
was observed on exposure to 10−5
M CdCl2. Natural
killer cell activity against yeast artificial chromosome
target cells, evaluated by flow cytometry, was
decreased only in cells exposed to 10−5
M HgCl2.

Conclusion and Clinical Relevance—Bovine leukocytes
are susceptible to the immunomodulatory
effects of in vitro exposure to heavy metals at concentrations
equal to or higher than those at which similar
effects are seen for leukocytes from most other animal
species for which data are available for comparison.
Exception is phagocytosis, which is severely affected
by low concentrations of CdCl2 and HgCl2 in cattle.
Reduction of defense mechanisms on exposure to
metals could lead to increased susceptibility to potential
pathogens.(Am J Vet Res 2000;61:339–344)
Intracellular microelectrode recording to characterize inhibitory neuromuscular transmission in jejunum of horses
Authors: Rakestraw Peter C. , Snyder Jack R. , Sanders Kenton M. , Shuttleworth William C.
Published: December 2005

Objective—To evaluate electrical activity of jejunal circular muscle in horses and characterize electrical responses to stimulation by intrinsic inhibitory neurons.

Sample Population—Portions of jejunum obtained from horses euthanatized for reasons other than gastrointestinal tract disease.

Procedure—Isolated circular muscle preparations were perfused with oxygenated modified Krebs solution. Glass microelectrodes were used for intracellular recording of membrane potentials from single smooth muscle cells. Electrical activity and responses to electrical field stimulation (EFS) of intrinsic neurons in the presence of guanethidine and atropine were recorded. Mediators of responses to nerve stimulation were also evaluated, usingN-nitro-L-arginine methyl ester (L-NAME) and apamin.

Results—Mean resting membrane potential (RMP) was 41.5 ± 1.8 mV. Small membrane potential oscillations were observed in muscle cells. Single or multiple action potentials were often superimposed on the peaks of these oscillations. Spontaneous oscillations and action potentials were blocked by nifedipine. Transient hyperpolarizations of smooth muscle cell membrane potentials (inhibitory junction potentials [IJP]) were observed in response to electrical field stimulation. The IJP evoked by stimulus trains consisted of an initial fast component followed by a slow component. The L-NAME did not have a significant effect on RMP and did not significantly affect the fast component of IJP at any stimulus frequency tested. In contrast, L-NAME abolished the slow component of IJP observed after trains of pulses. In the continued presence of L-NAME, apamin had no significant effect on RMP but effectively reduced the fast component of IJP.

Conclusions and Clinical Relevance—Findings suggest that inhibitory neurotransmitters supplying equine jejunum act through different ionic mechanisms. Understanding these mechanisms may suggest new therapeutic targets for treatment of motility disorders. (Am J Vet Res2000;61:362–368)
Effect of carboxymethylcellulose and a hyaluronate-carboxymethylcellulose membrane on healing of intestinal anastomoses in horses
Authors: Mueller P. O. Eric , Harmon Barry G. , Hay William P. , Amoroso Lisa M.
Published: December 2005

Objective—To evaluate the effect of sodium carboxymethylcellulose (SCMC) or a hyaluronate-carboxymethylcellulose membrane (HA membrane) on healing of the small intestine in horses.

Animals—18 healthy adult horses.

Procedure—Midline celiotomy and 2 jejunal resection- and-anastomosis surgeries were performed. In treated horses, SCMC (n = 6) or a HA membrane (6) was applied to the jejunum to cover the anastomosis. There were 6 untreated control horses. Horses were euthanatized 10 days after surgery. For each horse, 1 anastomosis was used for histologic examination, and the second was used to determine intestinal bursting strength. Intestinal bursting tension, serosal granulation tissue, serosal fibrin deposition, and width of the fibrous seal at the anastomosis were compared among groups.

Results—3 control horses had adhesions associated with the anastomosis, but none of the treated horses had adhesions associated with the anastomosis. Mean thickness of fibrin deposited on the serosal surfaces for the SCMC and HA-membrane groups was significantly less than that for control horses. Mean thickness of serosal granulation tissue, width of fibrous seal between inverted musculature, inflammatory cell infiltrate scores, and bursting tension did not differ significantly among groups.

Conclusions and Clinical Relevance—Use of SCMC or application of a HA membrane to small intestinal anastomoses in horses resulted in fewer adhesions and decreased fibrin deposition, and it did not adversely affect anastomotic healing. In horses at increased risk for intra-abdominal adhesions, SCMC or application of HA membranes may decrease the frequency of adhesions without adversely affecting healing of small intestinal anastomoses. (Am J Vet Res2000;61:369–374)
Expression of the α6 chain of type IV collagen in glomerular basement membranes of healthy adult dogs
Authors: Lees George E. , Kashtan Clifford E. , Michael Alfred F. , Helman R. Gayman , Naito Ichiro , Ninomiya Yoshifumi , Sado Yoshikazu , Kim Youngki
Published: December 2005

Objective—To evaluate expression of the α6 chain of type IV collagen in the glomerular basement membranes (GBM) of healthy dogs.

Sample Population—Kidney specimens from 12 healthy dogs. For comparison, kidney specimens from 8 human subjects between 25 and 83 years old also were evaluated.

Procedure—Sections were immunolabeled with a monospecific antibody that cross-reacts with human and canine α6(IV) chains and examined by means of fluorescence microscopy.

Results—Immunolabeling of the α6(IV) chain was not observed in GBM of 6 dogs ≤ 30 months old but was observed in GBM of the remaining 6 dogs, all of which were ≥ 45 months old. Expression of the α6(IV) chain was not observed in GBM of the human subjects, regardless of the age of the subject.

Conclusions and Clinical Relevance—Results indicate that the α6(IV) chain is expressed in GBM of healthy dogs, but the expression is age-dependent. Composition and structural organization of type IV collagen in the GBM of healthy adult dogs is different from that described for other species. (Am J Vet Res2000;61:38–41)
In vitro effects of erythromycin, lidocaine, and metoclopramide on smooth muscle from the pyloric antrum, proximal portion of the duodenum, and middle portion of the jejunum of horses
Authors: Nieto Jorge E. , Rakestraw Peter C. , Snyder Jack R. , Vatistas Nick J.
Published: December 2005

Objective—To evaluate effects of erythromycin, lidocaine, and metoclopramide on smooth muscle of the pyloric antrum (PA), proximal portion of the duodenum (PD), and middle portion of the jejunum (MJ) of horses.

Sample Population—Strips of smooth muscle from 7 horses.

Procedure—Isolated muscle strips were suspended in a bath and attached to isometric force transducers. Once stable spontaneous contractions were observed, agents were added. Isometric stress responses were compared with the amplitude of spontaneous contractions.

Results—A single dose of erythromycin to the PA increased contractile amplitude (CA) for the longitudinal smooth muscle (mean ± SEM, 76 ± 16 g/cm2) but decreased CA for circular smooth muscle (–79 ± 23 g/cm2). The inhibitory effect was decreased by tetrodotoxin, NG-nitro-L-arginine methyl ester, and a vasoactive intestinal peptide antagonist. Erythromycin increased CA for the MJ, which was maximal at 10–4M(171 ± 36 g/cm2). Lidocaine increased CA for the PD, which was maximal at 10–4M (60 ± 5 g/cm2). Metoclopramide increased the CA, which was maximal at 10–4Mfor the PA (75 ± 26 g/cm2), PD (279 ± 33 g/cm2), and MJ (456 ± 59 g/cm2).

Conclusions—Regional differences in responses to erythromycin, lidocaine, and metoclopramide were evident in the gastrointestinal tract of horses. Metoclopramide increased CA in all tissues used, whereas erythromycin inhibited CA in circular smooth muscle but stimulated CA in longitudinal smooth muscle from the PA. Inhibition is caused by stimulation of inhibitory nerves and is mediated, in part, by nitric oxide and vasoactive intestinal peptide. (Am J Vet Res2000;61:413–419)
Impedance audiometric measurements in clinically normal dogs
Authors: Cole Lynette K. , Podell Michael , Kwochka Kenneth W.
Published: December 2005

Objective—To measure impedance audiometric values in clinically normal dogs that were sedated or anesthetized, evaluate effects of ear flushing on tympanometric measurements, and determine effects of performing acoustic reflex testing in a sound-attenuated room.

Animals—35 mixed-breed and purebred clientowned dogs and 21 laboratory-bred Beagles.

Procedures—Tympanometry and acoustic reflex testing were performed on 27 mixed-breed and purebred dogs under isoflurane anesthesia in a non–sound-attenuated room and 21 Beagles under sedation in a sound-attenuated room. Tympanometry was performed on 8 mixed-breed dogs under halothane anesthesia before and after ear canal flushing.

Results—Among impedance audiometric values, ear canal volume and compliance peak were smaller in Beagles than in mixed-breed dogs; differences among other values were not detected. Ear canal volume was dependent on body weight. Differences were not found for tympanometric values measured before and after ear canal flushing.

Conclusions and Clinical Relevance—Results of this study established reference range values for impedance audiometric measurements in clinically normal dogs under isoflurane anesthesia or sedation. Acoustic reflex testing does not need to be performed in a sound-attenuated room. The ear canals of clinically normal dogs can be flushed prior to performing tympanometry without altering the results. Impedance audiometry may be a useful noninvasive procedure for the diagnosis of otitis media in dogs. (Am J Vet Res2000;61:442–445)
Inhibition of canine and feline alcohol dehydrogenase activity by fomepizole
Authors: Connally Heather E. , Hamar Dwayne W. , Thrall Mary Anna
Published: December 2005

Objective—To determine and compare substrate specificity and kinetic rate constants of feline and canine alcohol dehydrogenase (ADH) with ethanol (EtOH) and ethylene glycol (EG) as substrates in vitro, with and without fomepizole.

Sample Population—Livers from 3 dogs and 3 cats.

Procedure—Canine and feline ADH activity, in cytosolic fractions of homogenized liver, was determined by use of various concentrations of nicotinamide adenine dinucleotide (NAD), EtOH, or EG as substrates. Initial reaction velocities were calculated, and kinetic inhibition rate constants (Ki) for fomepizole were determined.

Results—Substrate specificity of canine and feline ADH for EtOH or EG was not significantly different. A 2-fold difference was detected in the maximal velocity of canine, compared with feline, ADH, using either substrate. Fomepizole Kiin feline hepatic homogenates was significantly greater than Kiin canine hepatic homogenates when either EtOH or EG was used as substrate (10- and 30-fold, respectively). A 6-fold increase in the concentration of fomepizole was required to achieve ADH inhibition, with feline homogenates equivalent to those of canine homogenates.

Conclusions and Clinical Relevance—Feline ADH has lower enzymatic capacity for turnover or is less concentrated in liver than canine ADH with regard to EtOH and EG catalysis. Canine ADH was more effectively inhibited by fomepizole than feline ADH. Results suggest that higher dosages of fomepizole may be more effective to treat cats with EG intoxication than dosages reported to treat dogs. (Am J Vet Res2000;61:450–455)
Oxidant stress in sled dogs subjected to repetitive endurance exercise
Authors: Hinchcliff Kenneth W. , Reinhart Gregory A. , DiSilvestro Robert , Reynolds Arleigh , Blostein-Fujii Ashley , Swenson Richard A.
Published: December 2005

Objective—To determine whether repetitive endurance exercise in sled dogs was associated with substantial lipid peroxidation, decreases in antioxidant capacity of the serum, and skeletal muscle damage.

Animals—24 lightly trained sled dogs.

Procedure—16 dogs completed a 58-km run on each of 3 consecutive days; the other 8 dogs (control) did not exercise during the study. Blood samples were collected before the first exercise run and after the first and third exercise runs. Plasma isoprostane and serum vitamin E concentrations, total antioxidant status of plasma, and serum creatine kinase activity were measured.

Results—Plasma isoprostane concentrations in dogs in the exercise group were significantly increased after the first exercise run and further significantly increased after the third exercise run. Serum vitamin E concentration was significantly decreased after the first exercise run in dogs in the exercise group, and this change persisted after the third exercise run. There was a significant linear relationship between plasma isoprostane concentration and the logarithm of serum creatine kinase activity (adjustedr2= 0.84).

Conclusions and Clinical Relevance—Results demonstrate that repetitive endurance exercise in dogs is associated with lipid peroxidation and a reduction in plasma antioxidant concentrations. We interpret these results as indicating that the antioxidant mechanisms of minimally trained dogs may, in some instances, be inadequate to meet the antioxidant requirements of repetitive endurance exercise. (Am J Vet Res2000;61:512–517)
Evaluation of intestinal permeability and gluten sensitivity in Soft-Coated Wheaten Terriers with familial protein-losing enteropathy, protein-losing nephropathy, or both
Authors: Vaden Shelly L. , Sellon Rance K. , Melgarejo L. Tonatiuh , Williams David A. , Trogdon Maureen M. , VanCamp Steven D. , Argenzio Robert A.
Published: December 2005

Objective—To evaluate intestinal permeability and gluten sensitivity in a family of Soft-Coated Wheaten Terriers (SCWT) affected with protein-losing enteropathy (PLE), protein-losing nephropathy (PLN), or both.

Animals—6 affected adult dogs.

Procedure—Intestinal biopsy specimens, urine protein- to-creatinine ratio, serum concentrations of albumin and globulin, and concentration of α1-protease inhibitor in feces were evaluated before, during, and 13 weeks after daily administration of 10 g of gluten for 7 weeks. Eosinophils and lymphocytes-plasmacytes were enumerated in intestinal biopsy specimens. Intestinal permeability was evaluated before and during the sixth week of gluten administration via cellobiose-mannitol and chromium-EDTA absorption tests.

Results—Serum globulin concentration decreased significantly after prolonged administration of gluten. Although not significant, there was an increase in lymphocytes- plasmacytes and a decrease in eosinophils in intestinal biopsy specimens. Furthermore, these counts were greater than those reported for clinically normal dogs. Gluten administration did not increase intestinal permeability.

Conclusions and Clinical Relevance—Daily administration of gluten was associated with a significant decrease in serum globulin concentration in SCWT affected with PLE or PLN, but other variables remained unchanged. Although enhanced wheatgluten sensitivity may be one factor involved in the pathogenesis of PLE or PLN in SCWT, this syndrome does not appear to be the result of a specific sensitivity to gluten. (Am J Vet Res2000;61:518–524)
Effects of tilmicosin treatment on Pasteurella haemolytica organisms in nasal secretion specimens of calves with respiratory tract disease
Authors: Frank Glynn H. , Briggs Robert E. , Loan Raymond W. , Purdy Charles W. , Zehr Emilie S.
Published: December 2005

Objective—To determine the effect of tilmicosin treatment on number ofPasteurella haemolytica(PH) organisms in nasal secretion specimens of calves with respiratory tract disease.

Animals—206 British mixed-breed beef calves, 2 to 5 months old.

Procedure—In 2 separate studies of outbreaks, calves (study 1, n = 101; study 2, n = 105) that developed respiratory tract disease after transport to a feedlot were treated with tilmicosin. Nasal secretion specimens were examined for PH organisms to determine the status of colonization.

Results—In both studies, PH serotypes A1 and A6 were isolated. In study 1, tilmicosin treatment eliminated or markedly reduced the number of PH organisms in calves on days 1, 4, and 5 after treatment. In study 2, tilmicosin treatment eliminated PH organisms in calves on days 1, 2, 5, and 6 after treatment.

Conclusions and Clinical Relevance—Overall, tilmicosin treatment increased the number of culture-positive calves that became culture-negative and decreased the number of culture-negative calves that became culture-positive for up to 6 days after treatment. Tilmicosin treatment decreased the number of PH organisms in nasal secretion specimens, which indicated that fewer PH organisms were available to infect the lungs or to infect other calves. By reducing colonization, prophylactic use of tilmicosin before transport or at the time of arrival at a feedlot is likely to reduce the incidence of acute respiratory tract disease in calves for the initial several days after arrival, which is the period when they are most susceptible to infectious organisms. (Am J Vet Res2000;61: 525–529)
Canine antibody response to Blastomyces dermatitidis WI-1 antigen
Authors: Klein Bruce S. , Squires Richard A. , Lloyd Janice K. Foyer , Ruge Daniel R. , Legendre Alfred M.
Published: December 2005

Objective—To assess whether dogs with blastomycosis produce antibodies against the WI-1 and A-antigens ofBlastomyces dermatitidisand whether the antibodies are useful in serodiagnosis.

Sample Population—359 serum samples obtained from 245 dogs.

Procedure—233 samples from 122 dogs with blastomycosis, and 1 sample each from 24 dogs with suspected blastomycosis, 51 control dogs without infection, and 48 healthy dogs from an enzootic region were obtained. Antibodies against WI-1 antigen were detected by radioimmunoassay (RIA). Serum samples were tested in parallel for antibodies against the Aantigen ofB dermatitidisby commercial agar-gel immunodiffusion (AGID) in a reference laboratory.

Results—Antibodies were detected in 92% of infected dogs by RIA and in 41% by AGID. For 29 serum samples that were obtained 11 to 1,545 days after diagnosis, antibodies were detected in 92% of samples by RIA and 7% by AGID. For 93 serial serum samples from 29 dogs with blastomycosis, the mean anti-WI-1 titer was 1:18,761 at the time of diagnosis, and decreased to a mean of 1:1,338 by 210 days after treatment was initiated. Of 24 dogs with suspected infection, antibodies were detected in 67% by RIA and 33% by AGID. Control dogs without blastomycosis had no detectable antibodies in either assay. Thus, sensitivity was 92% for RIA and 41% for AGID, and specificity was 100% for both tests.

Conclusions and Clinical Relevance—Anti-WI-1 antibodies are readily detected by RIA in dogs with blastomycosis. Titers become high, decline during treatment, and persist for months. Anti-A antibodies are sometimes detected with AGID, but these decrease quickly. (Am J Vet Res2000;61:554–558)
Gait and speed as exercise components of risk factors associated with onset of fatigue injury of the third metacarpal bone in 2-year-old Thoroughbred racehorses
Authors: Boston Ray C. , Nunamaker David M.
Published: December 2005

Objective—To determine the degree to which components of the training program of 2-year-old Thoroughbred racehorses influence their susceptibility to fatigue injury of the third metacarpal bone (bucked shins).

Animals—226 two-year-old Thoroughbred racehorses.

Procedure—Daily training information and health reports on 2-year-old Thoroughbreds were compiled from records provided from 5 commercial stables. For each horse, data (exercise variables) were collected that comprised distance jogged (approx speed of 5 m/s), galloped (approx 11 m/s), and breezed (approx 15 to 16 m/s) until a single instance of bucked shins was reported. Data were coded for analysis using cross-tabulation, graphic, and survival techniques.

Results—Of 226 horses, 56 had bucked shins, 9 completed the observation period without bucked shins, and 161 were lost to follow-up. Distinct training strategies were used at stables resulting in significantly different survival profiles among stables. Mean (± SD) allocation of exercise to breezing was 0.15 ± 0.13 miles/wk (maximum, 0.64 miles/wk), to galloping was 4.47 ± 1.52 miles/wk (maximum, 9.56 miles/wk), and to jogging was 2.34 ± 1.70 miles/wk (maximum, 8.53 miles/wk). Survival (ie, lack of bucked shins during 1 year of monitoring) was found to be significantly reduced by exercise allocation to breezing, significantly increased by exercise allocation to galloping, and uninfluenced by exercise allocation to jogging. The log of the hazard ratio was reduced by 4.2 ± 1.5/mile breezed and increased by 0.3 ± 0.1/mile galloped.

Conclusions and Clinical Relevance—Relationships between different gaits and speeds in the training regimen influence the incidence of bucked shins. To reduce the incidence of bucked shins, trainers should consider allocating more training effort to regular short-distance breezing and less to long-distance galloping. (Am J Vet Res2000;61:602–608)