bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of upper airway pressures in exercising horses with dorsal displacement of the soft palate
Authors: Rehder Renata S. , Ducharme Normand G. , Hackett Richard P. , Nielan Gary J.
Published: January 2024

To determine whether abnormal airway pressures have a role in development of dorsal displacement of the soft palate (ddsp), measurements of tracheal and pharyngeal pressures were correlated with nasopharyngeal morphology in exercising horses. Exercising videoendoscopy and measurement of tracheal and pharyngeal pressures were used in 14 clinically normal horses and 19 horses with intermittent ddsp. The pressure signals were superimposed on the videoendoscope image, and both images were saved simultaneously on a videocassette for slow motion analysis to determine the instant displacement occurred in the respiratory cycle. Horses were submitted to an escalating 8-minute high-speed test with a maximal speed of 14 m/s. Compared with clinically normal horses, horses with intermittent ddsp did not have excessively negative inspiratory pressures during exercise. Eight horses displaced the soft palate during inspiration, 4 horses displaced it during expiration, and 7 displaced it by swallowing. Some horses displaced the soft palate at the beginning of the exercise trial, before reaching maximal speed, some horses displaced it at the peak speed, and some horses displaced it when slowing down. Epiglottic size in horses with ddsp was within normal limits, ruling out epiglottic hypoplasia as a cause of ddsp during exercise. Airway pressures were significantly (P < 0.002) altered after ddsp. Pharyngeal and tracheal inspiratory pressures were less negative, whereas pharyngeal expiratory pressure became less positive and tracheal expiratory pressure became more positive after displacement, suggesting a decrease in airflow and an increase in expiratory resistance in the upper airway.
Differential cell analysis and phenotypic subtyping of lymphocytes in bronchoalveolar lavage fluid from clinically normal dogs
Authors: Vail David M. , Mahler Peter A. , Soergel Steve A.
Published: January 2024

In 33 healthy dogs, 66 bronchoalveolar lavage samples from the right and left caudal lung lobes were analyzed for volume of return, cellularity, differential cellularity, and immunophenotypic lymphocyte subpopulations. Lavage return was 64.8% (mean) following 3 sequential 25-ml lavages, for a total lavage volume of 75 ml. With this technique, 21.1 × 106 cells/sample (mean) were obtained. The cellular components of bronchoalveolar lavage samples, in decreasing order of frequency, were alveolar macrophages (79.4%), lymphocytes (13.5%), eosinophils (3.6%), mast cells (2.1%), epithelial cells (0.8%), and neutrophils (0.6%). Mean alveolar lymphocyte subpopulation frequencies, determined in 18 samples, for pan T, CD4, and CD8 cells were 52, 21.9, and 17.8%, respectively, with a CD4/CD8 ratio of 1.3. Variables analyzed did not vary between right and left caudal lung lobes, nor were they affected by body weight.
Diet effect on activity product ratios of uric acid, sodium urate, and ammonium urate in urine formed by healthy Beagles
Authors: Bartges Joseph W. , Osborne Carl A. , Felice Lawrence J. , Allen Timothy A. , Brown Charles , Unger Lisa K. , Koehler Lori A. , Bird Kathy A. , Chen Menglan
Published: January 2024

Urine activity product ratios of uric acid, sodium urate, and ammonium urate and urinary excretion of metabolites were determined in 24-hour samples produced by 6 healthy Beagles during periods of consumption of a low-protein, casein-based diet (diet A) and a high-protein, meat-based diet (diet B). Comparison of effects of diet A with those of diet B revealed: significantly lower activity product ratios of uric acid (P = 0.025), sodium urate (P = 0.045), and ammonium urate (P = 0.0045); significantly lower 24-hour urinary excretion of uric acid (P = 0.002), ammonia (P = 0.0002), sodium (P = 0.01), calcium (P = 0.005), phosphorus (P = 0.0003), magnesium (P = 0.01), and oxalic acid (P = 0.004); significantly (P = 0.0001) higher 24-hour urine pH; and significantly (P = 0.01) lower endogenous creatinine clearance. These results suggest that consumption of diet A minimizes changes in urine that predispose dogs to uric acid, sodium urate, and ammonium urate urolithiasis.
Laparoscopic anatomy of the equine abdomen
Authors: Galuppo Larry D. , Snyder Jack R. , Pascoe John R.
Published: January 2024

Laparoscopy was performed on 6 horses (2 mares, 2 geldings, 2 stallions) to determine the normal laparoscopic anatomy of the equine abdomen. After withholding feed for 36 hours, horses were examined from the left and right paralumbar fossae, and the visceral anatomic structures were recorded by videotape and photography. One mare developed emphysema located subcutaneously at the primary laparoscopic portal; otherwise, there were no complications. The anatomic structures of diagnostic importance that were observed in the left half of the abdomen were the hepatic duct; left lateral and quadrate lobes of the liver; stomach; spleen; left kidney with the associated nephrosplenic ligament; segments of jejunum, descending colon, and ascending colon; left side of the male and female reproductive tracts; urinary bladder; vaginal ring; and mesorchium. Important structures observed in the right side of the abdomen were portions of the common hepatic duct; left lateral, quadrate, and right lobes of the liver; caudate process of the liver; stomach; duodenum; right dorsal colon, epiploic foramen; omental bursa; right kidney; base of the cecum; segments of jejunum, descending colon, and ascending colon; urinary bladder; right half of the male and female reproductive tracts; and rectum.
Role of low dietary fat in the treatment of dogs with exocrine pancreatic insufficiency
Authors: Westermarck Elias , Junttila Juha T. , Wiberg Maria E.
Published: January 2024

The main objective of the study reported here was to determine whether signs typical of exocrine pancreatic insufficiency (epi) are alleviated when affected dogs are fed a diet with low fat content, compared with feeding ordinary commercial dog food or food prepared by the owner. The most cost-effective amount of enzyme supplement also was estimated. The study consisted of 6 test periods. Duration of the first and third periods was 4 weeks, and that of the others was 2 weeks. During the first 2 periods, the dogs were fed their original diet. The amount of enzyme supplement was reduced by half between the first and the second period. During the last 4 periods, the dogs were fed only the low-fat diet, and amount of the enzyme supplement was reduced stepwise. During the entire study, owners were asked to assess daily the severity of 9 signs typical of epi. A new index was established by adding the daily scores of each individual epi sign. This index was designated the epi index and was used as a measure of the general well-being of the dog. When the mean epi indexes of the original diet periods were compared with those of the corresponding low-fat diet periods, there were no statistically significant differences by use of Tukey's test or the paired t-test. There was considerable variability between dogs, however. The fat content of the original diet did not correlate with the difference in epi signs when the dogs were fed the low-fat diet. According to our study, feeding a low-fat diet to dogs with epi did not significantly alleviate clinical signs of the disease.

Decreasing the enzyme supplementation by 50% of the recommended dose did not significantly increase severity of the cumulative epi score. Decreasing the enzyme supplement by three-fourths of the recommended dose was excessive, and the severity of the clinical signs increased significantly (P < 0.05). The cost of the low-fat diet, compared with that of the original diet, was high.
Systemic and colonic venous hemostatic alterations in horses during low-flow ischemia and reperfusion of the large colon
Authors: Moore Rustin M. , Couto C. Guillermo , Muir William W. , Moore Bonnie Rush , Kociba Gary J.
Published: January 2024

Twenty-four horses were randomly allocated to 3 groups. All horses underwent a ventral midline celiotomy, and the large colon was exteriorized and instrumented. Group-1 horses served as sham-operated controls, group-2 horses underwent 6 hours of colonic ischemia, and group-3 horses were subjected to 3 hours of ischemia and 3 hours of reperfusion. Baseline blood samples were collected, then low-flow colonic ischemia was induced in horses of groups 2 and 3 by reducing colonic arterial blood flow to 20% of baseline. All horses were monitored for 6 hours. Citrated systemic venous (sv) blood samples were collected from the main pulmonary artery, and colonic venous (cv) samples were collected from the colonic vein draining the ventral colon. Samples were collected at 0, and 2, 3, 3.25, 4, and 6 hours for determination of one-stage prothrombin time, activated partial thromboplastin time, antithrombin III activity, and fibrinogen concentration. Data were analyzed statistically, using two-way anova for repeated measures, and post-hoc comparisons were made by use of Student Newman Keul's test. Statistical significance was set at P < 0.05. There were significant decreases in all hemostatic variables by 2 hours in sv and cv samples from horses of all 3 groups, but there were no differences among the 3 groups for any of these variables. These hemostatic alterations could have been secondary to a hypercoagulable state or to fluid therapy-induced hemodilution. Colonic ischemia-reperfusion was not the cause of these alterations because these alterations also were observed in the sham-operated control horses. Significant temporal alterations existed even after accounting for the hemodilution. The most plausible explanation for these alterations is that hemostatic activation was incited by the celiotomy and manipulation of the colon during exteriorization and instrumentation. Comparison of paired sv and cv samples for each hemostatic variable revealed significant differences for the absolute values of one-stage prothrombin time and fibrinogen concentration, but not for activated partial thromboplastin time or antithrombin III activity. This indicates that monitoring sv hemostatic variables does not necessarily provide an accurate assessment of hemostatic function in regional vascular beds. Largecolon ischemia with or without reperfusion did not alter hemostatic function.
Mechanical evaluation of transosseous wire rope configurations in a large animal external fixator
Authors: Rapoff Andrew J. , Markel Mark D. , Vanderby Ray
Published: January 2024

By use of wire ropes as the transosseous component, an external skeletal fixator for the repair of long bone fractures in horses and cattle has been designed and tested in axial compression. Theoretical methods were used in the design process to size fixator components; however, our results suggest that conventional methods of analyzing the displacement of the transosseous component may not apply to wire ropes. Large pretensions in the wire ropes are necessary to obtain functional stiffnesses for fracture fixation. Therefore, a method was sought for terminating the ropes so that an appropriate pretension could be introduced into the rope through its interface with the fixator rings. Ropes were terminated by use of 5 methods and were tested in axial tension to failure. These methods included 3 copper sleeve arrangements, welded ends, and drum sockets. The drum sockets (57.6% of rope breaking strength) far exceeded the strengths provided by the copper sleeves (8.5 to 26.6%) and the welded ends (44.3%). Using the drum sockets, 5 rope configurations were assembled to the fixator, using wood blocks to simulate bones with a gap defect. The fixator was loaded in axial compression for each of the rope configurations, and stiffnesses were determined from measured axial displacement and applied load. The 4-ring fixator configuration, with 2 ropes at 60° angular separation/ring, was the stiffest. In a worst case (gap) model, a mean axial compression load of 1,730 N was observed at 2 mm of displacement for a 4-ring fixator configuration. Our results suggest that, in less conservative scenarios where compression of the fracture surfaces can share limb loads, wire ropes may function well as the transosseous components of an external fixator.
Effects of age on temperature-related variation in motor nerve conduction velocity in healthy chickens
Authors: Bagley Rodney S. , Wheeler Simon J. , Gay John M.
Published: January 2024

Muscle potentials evoked by stimulation of the sciatic nerve were evaluated in 4- and 15-week-old chickens. Each bird was anesthetized and slowly cooled externally from a normal body temperature of 40 C to 28 C, and motor nerve conduction velocities were measured at various intervals during cooling. Motor nerve conduction velocity decreased linearly with decreasing limb temperature in both groups. The rate of change in motor nerve conduction velocity per degree in 2 groups (2.13 m/s/C vs 1.84 m/s/ C) fell just short of a statistically significant difference (P = 0.0508), indicating that an age-related effect on temperature-associated variation in motor nerve conduction velocity may be present.
Effects of furosemide, exercise, and atropine on tracheal mucus transport rate in horses
Authors: Maxson Abby D. , Soma Lawrence R. , May Laura L. , Martini Joli A.
Published: January 2024

Effects of furosemide, exercise, and atropine on tracheal mucus transport rate (tmtr) in horses were investigated. Atropine (0.02 mg/kg of body weight) administered iv or by aerosolization significantly (P < 0.05) decreased tmtr at 60, but not at 30 minutes after its administration in standing horses. Furosemide (1.0 mg/kg, iv) did not have any significant effect on tmtr when measured at 2 or 4 hours after its administration in standing horses. Exercise alone or furosemide (1.0 mg/kg, iv) administration followed 4 hours later by exercise did not alter tmtr, compared with values for standing control or exercised horses administered saline solution. Atropine (0.02 mg/kg, iv) administered after exercise significantly (P < 0.05) decreased tmtr, compared with values for no exercise standing controls, for exercise after administration of saline solution, and for furosemide and exercise.
Persistence of a single electropherotype and serotype (G6P5) of bovine rotavirus in calves on a closed dairy farm from 1990 to 1993
Authors: Ishizaki Hiroshi , Ohta Chikako , Shirahata Toshikazu , Goto Hitoshi , Taniguchi Koki , Urasawa Tomoko , Urasawa Shozo
Published: January 2024

A virologic survey was conducted on calves with diarrhea associated with bovine rotavirus (brv) on a closed dairy farm. The brv was detected from 32 of 219 (14.6%) fecal specimens repeatedly collected from 56 calves born during the years 1992-1993, regardless of whether they had diarrhea. Most of the 32 strains were isolated from fecal specimens obtained from 2- to 6-week-old calves. After electrophoresis of double-stranded viral rna from the 32 strains, genomic rna migration patterns were similar to those of the predominant brv strains isolated at the same farm during the years 1990-1991. All representative strains were identified as G serotype 6 (G6) and P type 5 (P5) by results of the virus-neutralization test and polymerase chain reaction procedure. Thus, brv had no change in genomic rna electropherotypes and serologic antigenicities in a closed dairy herd over a period of several years.
Trypanosoma cruzi infection in Walker Hounds from Virginia
Authors: Barr Stephen C. , Van Beek Olga , Carlisle-Nowak Melissa S. , Lopez Jorge W. , Kirchhoff Louis V. , Allison Neil , Zajac Anne , Lahunta Alexander de , Schlafer Donald H. , Crandall Wilson T.
Published: January 2024

Trypanosomiasis has been reported in dogs from Texas, Oklahoma, Louisiana, and South Carolina. We describe the first isolation and characterization of Trypanosoma cruzi from a Walker Hound pup in Virginia that also had postvaccinal distemper. The mother of the pup and 7 of its 8 siblings also were found to be infected with T cruzi, suggesting that the parasite had been transmitted transplacentally or through lactation. Parasitologic, serologic, histologic, and molecular methods were used to establish the diagnosis of T cruzi infection in these dogs. In a serologic survey of 12 dogs (including the sire of the pups) from the area in which the index case occurred, none were found to have antibodies to T cruzi. However, 2 of a further 52 dogs from different areas (to the index case), but in the same county, were seropositive to T cruzi. These findings indicate that canine trypanosomiasis is present in an area of the United States not previously known to be enzootic.
Plasma and synovial fluid kinetics, disposition, and urinary excretion of naproxen horses
Authors: Soma Lawrence R. , Uboh Cornelius E. , Rudy Jeffrey A. , Perkowski Sandra Z.
Published: January 2024

Naproxen (+6-methoxy- [α-methyl] -2-naphthalene acetic acid) is a nonsteroidal anti-inflammatory drug that is used for the treatment of inflammatory conditions in horses. We developed a model that describes the drug's disposition and renal excretion, including synovial fluid disposition and elimination after iv administration in horses. The plasma disposition, after iv administration of 5 mg/kg of body weight, was described by a two-compartment model; mean ± sd distribution and elimination half-lives were 1.42 ± 0.42 and 8.26 ± 2.56 hours, respectively. Plasma concentration of naproxen after iv administration of 5 mg/kg was 55.3 ± 13.5 and 0.61 ± 0.42 mg/L at 5 minutes and 48 hours after its administration, respectively. Steady-state volume of distribution was 0.163 ± 0.053 L/kg, and area under the plasma concentration time-curve was 372.1 ± 128.2 mg/h/L. The peak synovial fluid concentration of 12.68 ± 12.39 mg/L was measured at 6 hours, and decreased to 0.71 ± 0.38 mg/L at 36 hours after naproxen administration. The decrease of naproxen concentration in synovial fluid paralleled that in plasma. The appearance half-life of naproxen in synovial fluid was 4.64 hours, and the elimination half-life was 6.73 hours. Total body clearance was 0.015 ± 0.006 L/h/kg. The percentage of plasma protein binding was 97.0 ± 2.9% at plasma concentrations between 5 and 100 mg/L. This was significantly (P < 0.05) higher than the percentage of binding at plasma concentrations of 0.5, 1, and 500 mg/L, which was 75.2 ± 11.8%. Most of the drug was excreted as glucuronidated naproxen and unconjugated desmethylnaproxen. The recovery of naproxen and all metabolites in urine at 36 hours was 64.6 ± 7.2% of the total dose. Of this total, 39.6 ± 10.3% and 8.5 ± 7.9% were glucuronidated naproxen and desmethylnaproxen, respectively; 0.3 ± 0.1% and 16.6 ± 7.9% were free naproxen and desmethylnaproxen, respectively.
Regulation of neutrophil adhesion molecules and shedding of Staphylococcus aureus in milk of cortisol- and dexamethasone-treated cows
Authors: Burton Jeanne L. , Kehrli Marcus E.
Published: January 2024

The effects of 3 days of glucocorticoid administration on bovine blood neutrophil expression of l-selectin and CD18, and on the health status of mammary glands subclinically infected with Staphylococcus aureus were measured in 9 lactating Holsteins. The experiment was a 3 x 3 Latin square cross-over design, with 3 glucocorticoid treatments switched among groups of 3 cows/treatment during 3 periods. Treatments consisted of a vehicle (control, 10 ml of excipient/cow/d), cortisol (7.5,15, and 7.5 mg/cow on days 1, 2, and 3, respectively), and dexamethasone (0.04 mg/kg of body weight/cow/d for total daily dosages that ranged from 21.6 to 33.2 mg). Blood samples for immunostaining and flow cytometric analysis of l-selectin and CD18 and leukograms, as well as foremilk samples for determination of S aureus shedding, somatic cell counts, protein and fat percentages, and daily milk yields were collected repeatedly before, during, and after treatment days. Dexamethasone caused a profound, acute, short-lived down-regulation of l-selectin on neutrophils, which correlated in time to leukocytosis, mature and immature neutrophilias, increased shedding of S aureus in infected glands, and onset of high percentages of fat and protein and decreased milk yields. Dexamethasone also caused profound but delayed down-regulation of neutrophil CD18, which reached nadir simultaneously with reappearance of l-selectin-bearing neutrophils, normalized blood neutrophil counts, markedly high foremilk somatic cell counts and protein percentage, decreased S aureus shedding in milk, and finally, expression of clinical mastitis in some infected quarters. Each of these variables had returned to control (vehicle) values by the ninth (and last) sample collection day. Although cortisol treatment also decreased expression of l-selectin and CD18 on neutrophils, dosages used in this study were not sufficient to alter the number of circulating cells or to convert subclinical mammary gland infections to clinical mastitis. These results suggest that mammary gland health status can be altered by sudden exposure of blood neutrophils to glucocorticoids, because these steroid hormones caused profound down-regulation of the adhesion molecules that direct neutrophil margination and migration through the vascular endothelium. The results also reinforce the potential disease risk of treating infected animals with potent synthetic glucocorticoids, such as dexamethasone.
Study of transneuronal passage of pseudorabies virus in rat central nervous system by use of immunohistochemistry and in situ hybridization
Authors: Sur J. H. , Kim S. B. , Osorio F. A. , Moon O. K.
Published: January 2024

We studied the uptake and sequential transneuronal passage of pseudorabies virus (prv) in rat cns by use of a combination of immunohistochemistry and in situ hybridization. Protocols for rapid detection of prv by immunohistochemistry and in situ hybridization in rats with prv infection of the cns after intranasal instillation of a wild-type strain of prv were optimized in vitro, using porcine kidney-15 cells.

Pseudorabies virus-specific hybridization signals appeared in the cytoplasm and nucleus of prv-infected porcine kidney-15 cells by postinoculation (pi) hour 6. In tissue sections of prv-infected rats, prv nucleic acids were detected in areas of the rat brain in close proximity to the areas in which prv antigens were evident. The prv was initially found in the nucleus of trigeminal ganglion neurons at pi hour 24. At pi hour 72, prv antigens were observed in the mid-brain, and 24 hours later, in the telencephalon. We also found evidence of specific progressive transsynaptic transmission of the virus, and, on the basis of that, we have constructed a map of the synaptic contacts and pathways in the brain.

Therefore, combined use of immunohistochemistry and in situ hybridization was useful for characterizing the pathogenesis of prv in the cns of rats after intranasal inoculation, following a pattern that mimics prv infection of the natural host.
Effect of phenylbutazone and flunixin meglumine on acute toxic mastitis in dairy cows
Authors: Dascanio J. J. , Mechor G. D. , Gröhn Y. T. , Kenney D. G. , Booker C. A. , Thompson P. , Chiffelle C. L. , Musser J. M. M. , Warnick L. D.
Published: January 2024

A double-blinded randomized prospective clinical trial was designed to evaluate the effectiveness of flunixin meglumine and phenylbutazone for treatment of acute toxic mastitis in dairy cows. All cows were treated 4 times at 12-hour intervals by intramammary infusion of gentamicin (150 mg). A total of 45 dairy cows with toxic mastitis were randomly assigned to 1 of 3 treatment groups: group 1 (control), saline solution, iv; group 2,1 g of flunixin meglumine, iv; or group 3, 4 g of phenylbutazone, iv. Physical examination and udder variables were assessed at initial examination and 24 hours later. Milk production was recorded at regular intervals from 1 week before until 10 weeks after development of mastitis.

Rear quarters (34/45) were more commonly affected than front quarters. Thirty-five cows returned to the herd, 9 cows were culled, and 1 cow died. There were no significant differences among treatment groups in the need for further treatment or outcome. Klebsiella spp (18/45) and Escherichia coli (16/45) were the most common pathogens isolated by culture of milk from affected quarters. The overall bacteriologic cure rate on days 7 and 14 was 64 and 75%, respectively.

At the time of initial examination, cows of the control group had higher rectal temperature than did cows of the flunixin group. At the examination 24 hours later, the rectal temperature of cows in all treatment groups was lower than the temperature at initial examination; at that time (24 hours), however, there were no significant differences in temperature among the treatment groups.

Adjusted for stage of lactation, calving season, and parity, mastitic cows, compared with nonmastitic cows from the same herd, had lower milk production in the 10 weeks after development of mastitis, particularly during the week of onset. In repeated measures models, the loss of milk associated with mastitis was not significantly different among the 3 treatment groups.
Sustained release of liposome-encapsulated enrofloxacin after intramuscular administration in rabbits
Authors: Cabanes Ana , Reig Francesca , Antón José M. Garcia , Arboix Margarida
Published: January 2024

Enrofloxacin was encapsulated in multilamellar liposomes composed of phosphatidylcholine and cholesterol (molar ratio, 1:1), and its potential use as sustained release formulation was evaluated. The encapsulated drug was administered im to rabbits (n = 6). Results indicated that absorption rate was slow, compared with previous studies; additionally, peak concentration was lower (0.5 ± 0.1 µg/ml), and the time to peak concentration was considerably longer for liposome-encapsulated enrofloxacin (1.5 ± 1.08 hours) than for unencapsulated drug. Apparent elimination half-life of drug in the body was significantly (P < 0.05) increased (4.05 ± 1.08 hours) when it was administered encapsulated in liposomes. Large-size liposomes containing enrofloxacin administered im to rabbits gave sustained drug release from the injection site, providing therapeutic and prolonged plasma concentrations of drug in the body.
Responses of blood and plasma lactate and plasma purine concentrations to maximal exercise and their relation to performance in Standardbred trotters
Authors: Räsänen Leena A. , Lampinen Kimmo J. , Pösö A. Reeta
Published: January 2024

Objective

To study whether end products of 2 pathways of anaerobic energy metabolism, lactate and purines, that accumulate in the blood after intense exercise indicate any relation to exercise performance.

Design

Venous blood samples were taken within 1 and 15 minutes after a trotting race of 2,100 m.

Animale

16 Clinically healthy Standardbred trotters.

Procedure

Blood and plasma lactate concentrations were measured by enzymatic analyzer, and purines, uric acid and allantoin, were determined by high-performance liquid chromatography. The concentrations of metabolites were then correlated to racing time and individual performance indexes that are annually calculated from the percentage of winnings, placings, and starts rejected, average earnings per start, and the racing record.

Results

Blood lactate concentration immediately and calculated cell lactate concentration immediately and 15 minutes after the race correlated positively (P < 0.05 to P < 0.01) with the individual performance indexes. Plasma lactate concentration was not correlated to the individual performance indexes. Uric acid concentration, immediately and 15 minutes after the race, was negatively correlated (P < 0.05) to the individual performance indexes, and a positive relation (P < 0.05) was found between the highest concentration of uric acid and the racing time. Concentration of allantoin immediately or 15 minutes after the race did not have any significant correlation to the individual performance indexes.

Conclusions

Accumulation of lactate in the blood, which was greater in the superior performing horses, may prove to be an useful predictor of anaerobic capacity. The results also indicate that the loss of purine nucleotides was less in the superior performing horses, although further studies are needed to confirm this.
Effects of aging on the endodontic system, reserve crown, and roots of equine mandibular cheek teeth
Authors: Kirkland Khristina D. , Baker Gordon J. , Marretta Sandra Manfra , Eurell Jo Ann C. , Losonsky John M.
Published: January 2024

Objective

To document age-related changes in the morphology of the endodontic system, reserve crown, and roots of equine mandibular cheek teeth.

Design

Equine mandibular cheek teeth from horses of various ages were compared, using radiography, x-ray computed tomography, and histologic examinations.

Sample Population

48 right hemi-mandibles from horses 2 to 9 years old.

Procedure

Hemi-mandibles were radiographed, imaged by computed tomographic reconstruction, and reformatted. Histologic examination was used to identify and correlate tissue types.

Results

Permanent mandibular cheek teeth of the horse, at the time of eruption, consisted of an exposed crown and a reserve crown with a widely dilated apex. The endodontic system consisted of 5 or 6 pulp horns that connected to an expansive pulp in the reserve crown, which was confluent with the primordial pulp bulb surrounding the tooth’s apex.

At the time of eruption, mandibular cheek teeth did not have a distinct pulp chamber, roots, or evidence of root formation. However, within 2 years after eruption, mesial and distal roots and a pulp chamber were present. A distinct pulp chamber, communicating with the pulp horns and both root pulp canals, was identifiable for 4 to 5 years from the time of root formation. The endodontic system of cheek teeth, 6 to 8 years after eruption, consisted of 2 unattached compartments, made up of a root canal, pulp chamber, and 2 or 3 pulp horns.

Clinical Relevance

The age-related morphologic changes in equine mandibular cheek teeth have important implications for application of endodontic therapy in horses. (Am J Vet Res 1996;57:31-38)
Reliability of a single fecal egg per gram determination as a measure of individual and herd values for trichostrongyle nematodes of cattle
Authors: Gasbarre Louis C. , Leighton Eldin A. , Bryant Dean
Published: January 2024

Objectives

To determine precision of a single fecal egg count, to evaluate the necessity of repeated testing to ascertain the number of parasite eggs found per gram of fecal material (EPG) of a given animal, and to infer the number of cattle that must be sampled to estimate the mean EPG value of a given herd.

Design

Calves born in 4 successive years were tested for 3 consecutive days in May, July, and September to determine their fecal EPG value. Results were analyzed to determine important sources of variance in the EPG values.

Animals

427 Black Angus calves.

Procedures

Nematode EPG values were determined by zinc sulfate flotation of fecal samples taken from the rectum. Variance components were estimated by restricted maximal likelihood procedures.

Results

The largest source of variation in fecal egg counts arose from differences among calves. Variation associated with sampling within calf was larger than that associated with year of sampling or day when samples were taken. Repeatability of EPG determinations was between 0.4 and 0.7.

Conclusions

Collection of 3 replicate samples reduced variance associated with a single calf mean by 25 to 30%. Additional replication would further reduce the variance, but at a diminishing rate. To accurately estimate mean EPG for a herd, a randomly drawn sample should be similar in composition to the herd and include at least 1 animal from the high EPG group, which often constitutes 15 to 20% of the calves. To ensure that, on average, 95% of the samples drawn contain 1 or more animals with high EPG, the sample must include 15 to 20 animals within the grazing group under study.
Study of hereditary cerebellar degeneration in cats
Authors: Inada Shichiro , Mochizuki Masami , Izumo Shuji , Kuriyama Masaru , Sakamoto Hiroshi , Kawasaki Yasuaki , Osame Mitsuhiro
Published: January 2024

Objective

To elucidate the nature of ataxia observed in 3 cats spanning 2 generations.

Design

Experimental breeding was attempted to confirm heritability of the disease and establish the mode of inheritance; the original 3 cats and their offspring were studied.

Animals

Seven diseased cats spanning 3 generations and 11 neurologically normal cats.

Procedure

Cats were examined by use of the following methods: clinical observation, hematologic and serum biochemical examinations, neurologic examination, electrodiagnostics, magnetic resonance imaging, lysosomal enzyme activity assay, horizontal transmission test, and virologic and pathologic examinations.

Results

All kittens (1 male and 3 females) obtained by backcrosses developed pure cerebellar dysfunction from the age of 7 to 8 weeks onward. It became progressively worse, but not fatal, between 1 and 2.5 months. Prenatal or perinatal infection with feline panleukopenia virus, inherited lysosomal storage diseases, including gangliosidosis and mannosidosis, and feline hereditary neuroaxonal dystrophy were excluded. Magnetic resonance imaging indicated that size of the cerebellum of diseased cats was markedly reduced. Cerebellar cortical degeneration, especially with extensive destruction of Purkinje cells, was observed microscopically.

Conclusion

The disease was concluded to be cerebellar degeneration of a new clinical form in cats having an autosomal recessive mode of inheritance.

Clinical Relevance

When cerebellar dysfunction is diagnosed in a cat, hereditary cerebellar degeneration of this type should be considered in the differential diagnosis.(Am J Vet Res 1996; 57: 296-301)
Role of milk fractions, serum, and divalent cations in protection of mammary epithelial cells of cows against damage by Staphylococcus aureus toxins
Authors: Cifrian Eduardo , Guidry Albert J. , Marquardt Warren W.
Published: January 2024

Objective

To determine the effect of milk and blood serum constituents on cytotoxicity of Staphylococcus aureus on mammary epithelial cells.

Design

In vitro incubation of cells with cytotoxic agents and milk and serum constituents.

Sample Population

Mammary cells, milk, and blood obtained from 3 cows.

Procedure

Staphylococcal α-toxin and culture supernatants from S aureus M60 and an α-toxin-negative mutant of M60 were incubated with bovine mammary epithelial cells in the presence of milk fractions, serum, and divalent cations. Propidium iodide fluorescence was used as a measure of cell damage.

Results

Skim milk and milk whey inhibited S aureus cytotoxic agents. Skim milk protected against α-toxin damage to a greater extent than milk whey. Serum from an adult animal was more protective than was fetal serum. Milk fat and serum albumin had no protective effect. Divalent calcium and Mg2+ were more effective inhibitors of mammary epithelial cell damage caused by α-toxin than of damage attributable to M60 culture supernatant. Divalent calcium and Mg2+ at concentrations similar to those of free Ca2+ and Mg2+ in normal bovine milk decreased cytotoxic damage attributable to α-toxin. However, concentrations similar to those of total Ca2+ and Mg2+ in normal milk were required to decrease cell damage caused by M60 culture supernatant. The α-toxin-negative mutant was less cytotoxic than the M60 parent strain.

Conclusions

Casein, as well as Ca2+ and Mg2+ in bovine milk, inhibit the cytotoxic effect of S aureus on mammary epithelial cells.(Am J Vet Res 1996;57:308-312)
Effects of hematocrit and erythrocyte deformability on pulmonary vascular pressures in perfused pony lungs
Authors: Weiss Douglas J. , Richwagen Kristin , Evanson Oral A.
Published: January 2024

Objective

To evaluate the contribution of hematocrit and RBC deformability to pulmonary vascular pressures of racehorses.

Design

Pony lungs were isolated and right and left lungs were perfused separately with blood. The effects of changing hematocrit and of pentoxifylline treatment were evaluated.

Animals

11 healthy mixed-breed ponies.

Procedure

Ponies were anesthesized, blood was collected, and lungs were removed and perfused with blood at constant flow rate.

Results

Increasing the hematocrit from 35% to 65% resulted in increases in pulmonary arterial pressure (53%, 45%), capillary shear stress (45%, 32%), and total vascular resistance (92%, 143%) at low (352 ± 33 ml/min) and high (1,442 ± 48 ml/min) flow rates, respectively. Pulmonary artery pressures were lower (10%, 11%) when lungs were perfused with blood from pentoxifylline-treated ponies, compared with blood from control ponies with low hematocrit (PCV, 30%) and low-flow rate and with high hematocrit (PCV, 45%) and high flow rate, respectively. Decreases in capillary shear stress and total vascular resistance were also observed for pentoxifylline-treated blood.

Conclusions

Increases in hematocrit equivalent to those occurring during competitive racing activity contribute substantially to pulmonary vascular pressures in horse lungs. Administration of pentoxifylline to ponies reduced RBC deformability and attenuated increases in pulmonary vascular pressures.

Clinical Relevance

Treatment of racehorses with pentoxifylline may reduce exercise-associated increases in pulmonary vacular pressure, thereby attenuating exercise-induced pulmonary hemorrhage.(Am J Vet Res 1996;57:346-350)
Cytokine release by porcine livers perfused with lipopolysaccharide or live Salmonella choleraesuis
Authors: Frank Dagmar E. , Ahrens Franklin A. , Kramer Ted T.
Published: January 2024

Objective

To develop a model to study the kinetics and relative amounts of cytokines produced by liver cells during enteric infection.

Design

Salmonella enteriditis lipopolysaccharide (LPS)-or live S choleraesuis-stimulated isolated livers from clinically normal pigs and pigs with active acute phase response.

Animals

7- to 14-day-old salmonellosis-free pigs, 4 to 12/group.

Procedure

Livers were removed and perfused with oxygenated Krebs-Henseleit solution for 30 minutes and with S choleraesuis or LPS added for 7 minutes. Livers were then perfused with 500 ml of fresh solution in a closed loop procedure for 180 minutes. Perfusate samples were collected for tumor necrosis factor-α (TNFα) and interleukin 6 (IL-6) bioassays.

Results

Tumor necrosis factor-α values remained constant during perfusion of normal livers and increased in those exposed to LPS. Interleukin 6 values increased in perfusate from normal livers from 30 to 150 minutes, then decreased. In livers from pigs with an active acute phase response, TNFα values were reduced; IL-6 appeared by 2 minutes and decreased after 25 minutes.

Conclusions

Isolated livers could be kept viable for 3 hours, and IL-6 and TNFα could be measured by the bioassays used.

Clinical Relevance

Model can be used for studying and modifying the response of liver cells to infective agents. (Am J Vet Res 1996;57:472–476)
Hybridization of 2,659 Clostridium perfringens isolates with gene probes for seven toxins (α, β, ε, ι, θ, μ, and enterotoxin) and for sialidase
Authors: Daube Georges , Simon Patricia , Limbourg Bernard , Manteca Christophe , Mainil Jacques , Kaeckenbeeck Albert
Published: January 2024

Objective

To genetically characterize Clostridium perfringens isolates for association of pathologic type with various diseases.

Design

Prospective study.

Sample Population

2,659 C perfringens isolates from various nonhuman animals species, human beings, and foods.

Procedure

Colony hybridization with DNA probes for 7 toxin (α, β, ε, ι (subunits a and b), θ, μ, and enterotoxin) genes and 1 sialidase gene were performed to group the isolates by pathologic type.

Results

Enterotoxin-negative type-A isolates were the most common (2,575/2,659), were isolated from all sources, and were separated into 5 pathologic types. In cattle and horses with enterotoxemia, essentially only these pathologic types were identified. The enterotoxin-negative isolates of types C or D each had a single pathologic type. Type-C isolates were isolated only from swine with necrotic enteritis and type-D isolates from small ruminants with enterotoxemia, except that 1 type-D isolate was also found from a healthy fish. Type-B or -E isolates were not found. Among the 47 enterotoxin-positive isolates, 5 isolates from sheep or deer were type D and the other 42 were type A. These 42 isolates were grouped into 3 pathologic types: 1 type was isolated from samples of almost all origins, but the other 2 types were found in only 5 fish, 4 human beings, and 1 dog.

Conclusions and Clinical Relevance

Genetic characterization of these isolates allowed identification of 11 different pathologic types. This approach may be useful in molecular diagnosis and prophylaxis of clostridial disease. (Am J Vet Res 1996;57:496–501)
Mechanisms of acid injury in porcine gastroesophageal mucosa
Authors: Argenzio Robert A. , Eisemann Joan
Published: January 2024

Objective

To identify the cause and mechanisms of injury in gastroesophageal ulcer disease in market weight swine.

Design

Comparison of mechanisms of injury caused by HCI with those caused by short chain fatty acids (SCFA) in gastric mucosa.

Animals

Pigs weighing 30 to 40 kg.

Procedure

Gastric tissues were studied in Ussing chambers; short-circuit current (Isc) and electrical resistance (R) were recorded in response to treatment, and tissues were examined histologically.

Results

60 mM mucosal acetate abruptly (≤ 75 minutes) and irreversibly abolished Isc at pH ≤ 4.5, whereas R decreased more slowly. These data were associated with cell swelling and vesicle formation in mid-zonal layers, followed by sloughing of the outer barrier, erosion into deeper zones, and finally, ulceration. Mucosal HCI at pH > 1.5 was ineffective; however, at pH 1.5, HCI induced an abrupt decrease in R, followed by a slow decrease in Isc, an effect opposite to that caused by SCFA. Serosal addition of HCI rapidly abolished Isc suggesting a barrier to free H+ diffusion from the mucosal solution.

Conclusions

Undissociated SCFA rapidly penetrate the outer barrier and acidify underlying viable tissue. Cellular acidification inhibits Na pumping and osmoregulation, resulting in cell swelling and necrosis. In contrast, HCI induces an increase in outer barrier permeability before accessing the transporting cells, a much longer process (≥ 5 hours) requiring a lower pH. These studies suggest that microbial production of SCFA may be important in the pathogenesis of porcine gastric ulcers. (Am J Vet Res 1996;57:564-573)
Comparison of the abilities of serologic tests to detect pseudorabies-infected pigs during the latent phase of infection
Authors: White Amy K. , Ciacci-Zanella Janice , Galeota Judith , Ele Shirley , Osorio Fernando A.
Published: January 2024

Objective

To compare the sensitivities of all available serologic tests in detecting pseudorabies virus (PRV) antibodies in pigs during long-term latent pseudorabies.

Design

Pigs experimentally infected with a virulent strain of PRV were maintained for 2 to 27 months after inoculation. At the time of necropsy of each pig, blood was collected for serologic evaluation, and tissues were obtained for polymerase chain reaction (PCR) verification of latency.

Animals

65 crossbred pigs each weighing approximately 18 kg at the start of the study.

Procedure

Serum samples from each pig were analyzed by serum neutralization, latex agglutination, screening ELISA, particle concentration fluorescence immunoassay, automated latex agglutination, and differential ELISA for glycoproteins I, III, and X. DNA was extracted from the trigeminal ganglia and tonsils of each pig and was analyzed by PCR for PRV genomic sequences.

Results

PCR analysis of trigeminal ganglia and tonsils indicated that all pigs were latently infected with PRV at the time of necropsy, and serologic testing verified that all pigs had PRV-specific antibodies, regardless of duration of infection. The screening tests were virtually equivalent in sensitivity for detection of PRV antibodies. Of the differential serologic tests, the glycoprotein-l and -III marker systems, which performed with similar sensitivity as the screening tests, were superior to the glycoprotein- X marker system in detecting PRV antibodies in latently infected pigs

Conclusion

Serologic testing consistently detects pigs in the latent phase of PRV infection, provided that the test detects the antibody response to the whole virus or to a reliable PRV-marker glycoprotein. (Am J Vet Res 1996; 57:608–611)
Mutation segregation and rapid carrier detection of X-linked muscular dystrophy in dogs
Authors: Bartlett R. J. , Winand N. J. , Secore S. L. , Singer J. T. , Fletcher S. , Wilton S. , Bogan D. J. , Metcalf-Bogan J. R. , Bartlett W. T. , Howell J. M. , Cooper B. J. , Kornegay J. N.
Published: January 2024

Objectives

To use exon 7-specific genomic polymerase chain reaction (PCR) products to identify the genotypes of normal, affected, and carrier female dogs in pedigrees segregating Golden Retriever muscular dystrophy (GRMD), and to confirm the concordant segregation of the mutation in all carrier and affected dogs presently available.

Design

The GRMD mutation is found in the consensus splice acceptor site in intron 6 of the canine dystrophin gene PCR cycle-sequencing and restriction fragment length polymorphism/PCR were used for determination of the pattern of segregation of the point mutation which causes GRMD.

Animals

Normal, clinically affected, and obligate carrier dogs in pedigrees of GRMD.

Procedure

DNA from blood was amplified, using PCR and primers that bracket all of exon 7 of the canine dystrophin gene as well as 100 base pairs of intron on either side. PCR products were either cycle-sequenced directly or submitted to a second round of PCR, using 1 of the original primers coupled with a mutagenic restriction fragment length polymorphism-primer, which thus creates an artificial restriction site. Digestion with Stu I detected the normal allele. To detect the affected allele, Sau96 I was used to digest the 310-base pair exon 7 genomic fragment directly.

Conclusions

Simple, clear diagnosis of carrier status was possible using these methods. This mutation is passed through all carrier and affected dogs in both United States GRMD colonies and the colony in Australia.

Clinical Relevance

Rapid, accurate diagnosis of carrier and affected dogs will enhance study of this homologue of Duchenne muscular dystrophy. (Am J Vet Res 1996; 57:650–654)