bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasonographic assessment of bladder neck mobility in continent bitches and bitches with urinary incontinence attributable to urethral sphincter mechanism incompetence
Authors: Atalan Gultekin , Holt Peter E. , Barr Frances J.
Published: January 2024

Objective

To determine bladder neck positional changes between standing and recumbent positions in bitches and whether change is related to continence status or general anesthesia, or both, and to evaluate reproducibility of measurements.

Animals

45 continent animals and 46 incontinent bitches with urethral sphincter mechanism incompetence (SMI).

Procedure

Distance between the bladder neck and perineal skin was measured ultrasonographically via the perineum while each dog was conscious in standing and right lateral recumbency and in right lateral recumbency under general anesthesia. Measurements of the bladder neck position obtained in right lateral recumbency under anesthesia were compared with radiographic measurements of the same parameter. Reproducibility of the ultrasonographic measurements of the distance between bladder neck and perineum was assessed on 3 occasions for each position in 50 dogs.

Results

In all dogs, differences in bladder neck position between standing and recumbent conscious-associated positions were not significant. However, caudal bladder neck movement between standing conscious- and recumbent anesthesia-associated positions and between recumbent conscious- and anesthesia-associated positions was significant for all dogs. Incontinent bitches had greater degree of caudal bladder movement during anesthesia. Mean difference in bladder neck positions between recumbent conscious- and recumbent anesthesia-associated positions was 0.24 cm in continent, compared with 0.73 cm in incontinent, bitches. Radiographic measurements were significantly greater than ultrasonographic measurements. Differences between repeated measurements for standing position were not significant, but those for recumbent conscious- and recumbent anesthesia-associated positions were significant.

Conclusions

Additional vesicourethral support mechanisms in continent dogs, are deficient in bitches with SMI, allowing the bladder neck to move further caudad. (Am J Vet Res 1998;59:673-679)
Effects of medetomidine on serum osmolality; urine volume, osmolality and pH; free water clearance; and fractional clearance of sodium, chloride, potassium, and glucose in dogs
Authors: Burton Shelley , Lemke Kip A. , Ihle Sherri L. , Mackenzie Allan L.
Published: January 2024

Objective

To determine effects of IV medetomidine administration on selected clinicopathologic variables in dogs.

Animals

6 healthy adult Beagles.

Procedure

Dogs were randomly assigned to each of 3 treatments in a crossover study design. Serum osmolality, urine osmolality, urine pH, and fractional clearances of sodium, chloride, potassium, and glucose were determined before and 20, 40, 60, 120, 180, 240, 300, 360, 420, and 480 minutes after IV administration of 0.9% NaCl (saline) solution (control) or medetomidine (10 or 20 μg/kg of body weight). The urinary bladder was emptied prior to saline or medetomidine administration, and urine volume was determined at the same posttreatment times as those described previously. Free water clearance was calculated for all posttreatment times.

Results

After medetomidine administration, serum osmolality, urine volume, free water clearance, and fractional clearance of potassium and glucose increased; urine osmolality decreased. Initially, urine pH and fractional clearance of chloride decreased, then subsequently increased. Fractional clearance of sodium did not change.

Conclusions and Clinical Relevance

Because IV administration of medetomidine to dogs at dosages of 10 and 20 μg/kg induces a diuretic effect that lasts up to 4 hours, the drug should be used with discretion in hypovolemic or dehydrated dogs, and its use should be avoided in those with urinary tract obstruction. (Am J Vet Res 1998;59:756-761)
Detection of feline herpesvirus 1 DNA in corneas of cats with eosinophilic keratitis or corneal sequestration
Authors: Nasisse Mark P. , Glover Tony L. , Moore Cecil P. , Weigler Benjamin J.
Published: January 2024

Objective

To determine whether feline herpesvirus 1 (FHV-1) DNA is in the corneas of clinically normal cats and cats with eosinophilic keratitis or corneal sequestration.

Sample Population

Corneal biopsy specimens obtained from cats referred for treatment of corneal sequestration or eosinophilic keratitis.

Procedure

Corneal scraping or keratectomy specimens collected from clinically normal cats, cats with eosinophilic keratitis, and cats with corneal sequestration were evaluated for FHV-1 DNA by use of polymerase chain reaction (PCR). DNA was extracted from the tissue, and 1 μg was assayed for FHV-1 by use of a single-round (40 cycles) PCR assay with primers directed at a 322-bp region of the thymidine kinase gene. Polymerase chain reaction positivity for clinically normal and affected cats of various breeds was compared by χ2 analysis at α = 0.05.

Results

The FHV-1 DNA was detected in 5.9% (1/17) of corneas from clinically normal cats, in 55.1% (86/156) of corneal sequestra, and in 76.3% (45/59) of scraping specimens from cats with eosinophilic keratitis. Prevalence was significantly (P < 0.001) greater for cats with corneal sequestration or eosinophilic keratitis than for clinically normal cats. For cats with corneal sequestration, prevalence of FHV-1 DNA was significantly lower in Persian and Himalayan, compared with domestic shorthair and longhair breeds.

Conclusion

Data strongly imply involvement of FHV-1 in the pathogenesis of eosinophilic keratitis and corneal sequestration. In Persian and Himalayan breeds, however, other nonviral factors also appear to be involved.

Clinical Relevance

Feline herpesvirus 1 must be considered when treating cats with corneal sequestration or eosinophilic keratitis. (Am J Vet Res 1998;59:856–858)
Regional distribution of blood flow in the brain of horses at rest and during exercise
Authors: Manohar Murli , Goetz Thomas E.
Published: January 2024

Objective

To examine regional distribution of blood flow in the brain of horses at rest and during exercise.

Animals

9 clinically normal horses.

Procedure

Regional brain blood flow was measured using radionuclide-labeled 15-μm-diameter microspheres injected into the left ventricle, while reference blood samples were obtained from the aorta.

Results

At rest, cerebral cortex and caudate nuclei received significantly higher blood flow, compared with cerebral white matter. A similar perfusion heterogeneity existed in the cerebellum. In the brain stem, a gradual tapering of blood flow from thalamus-hypothalamus towards medulla was observed in standing horses. Progressive significant increases in heart rate and in aortic and right atrial pressures occurred during exercise at 8 and 13 m/s, and horses developed significant arterial hypoxemia and hypercapnia. Cerebral and cerebellar gray- to white-matter perfusion heterogeneity was maintained during exercise, indicating differential metabolic O2 needs. Despite arterial hypoxemia, hypercapnia, and hypertension, exercise did not result in significant changes in blood flow to the cerebral cortex and caudate nuclei whereas, in cerebral white matter, a significant decrease in blood flow was observed. In all cerebral tissues, vascular resistance increased during exercise, indicating autoregulation of cerebral blood flow. In the cerebellar cortex, blood flow increased significantly with strenuous exercise as vasodilation occurred. Vascular resistance in cerebellar white matter increased during exercise at 13 m/s. Blood flow in the medulla, pons, midbrain, and thalamus-hypothalamus was not significantly altered during exercise from that at rest.

Conclusion

Despite arterial hypoxemia, hypercapnia, and hypertension, autoregulation of cerebral and cerebellar blood flow is maintained in horses during exercise. (Am J Vet Res 1998;59:893–897)
Functional anatomy of the cartilage of the distal phalanx and digital cushion in the equine foot and a hemodynamic flow hypothesis of energy dissipation
Authors: Bowker Robert M. , Van Wulfen Kimberly K. , Springer Susan E. , Linder Keith E.
Published: January 2024

Objectives

To examine macro- and microscopic characteristics of cartilage of the distal phalanx (ungual cartilage [UC]) and digital cushion in the equine foot and to relate them to the foot's function of energy dissipation.

Animals

85 horses and 5 foals of various breeds and ages.

Procedure

Feet, obtained at necropsy, were perfused with India ink (n = 30), latex (5), or polymer plastic (10). Select feet were examined histologically for tissue architecture and to identify elastic fibers. Immunochemistry to identify substance P peptides in nerves (feet from foals) and gold chloride impregnation of axons (n = 10) were performed. Feet were sectioned transversely (n = 27) or coronally (62 feet in a matched-paired study). Ungual cartilage was measured at the navicular bone. Digital cushions were examined for relative tissue composition between forefeet and hind feet.

Results

Ungual cartilage formed an axial projection that extended towards the midline to overlie the bars, and dorsally along the semilunar line of the distal phalanx. Ungual cartilage of forefeet was significantly larger than that of hind feet. The digital cushion was composed of fat and elastic tissues in feet with thin UC, or fibrous and fibrocartilaginous tissue and elastic tissue in feet with thicker UC. Sensory nerves and an extensive network of venovenous anastomoses were found in the UC.

Conclusions and Clinical Relevance

Ungual cartilage and the digital cushion provide the basis for a hemodynamic flow hypothesis of energy dissipation. Maximum energy dissipation depends on proper hoof preparation and shoeing. (Am J Vet Res 1998;59:961–968)
Time course of gastrointestinal tract permeability to chromium 51-labeled ethylenediaminetetraacetate in healthy dogs
Authors: Marks Stanley L. , Williams David A.
Published: January 2024

Objectives

To establish values for gastrointestinal tract permeation by chromium 51-labeled ethylenediaminetetraacetate (51Cr-labeled EDTA) in healthy adult dogs, and to evaluate the time course for 51Cr-labeled EDTA absorption over a 24-hour period after its administration, in an effort to define a shorter, more practical collection method.

Animals

6 healthy adult mixed-breed dogs.

Procedure

After an 18-hour nonfeeding period, each dog was given a solution containing 50 μCi of 51Cr-labeled EDTA in deionized water (10 ml/kg of body weight) by stomach tube. Complete urine collection was done at 2, 4, 6, and 24 hours after 51Cr-labeled EDTA administration. Five-milliliter samples of urine were counted for 15 minutes in a gamma counter, and radioactivity in urine was expressed as a percentage of the orally administered dose.

Results

Median (range) 24-hour urinary recovery of 51Cr-labeled EDTA after 24 hours was 15.1 (12.7 to 20.3)%. Urine collected at 2, 4, and 6 hours contained 1.0 (0.2 to 3.5)%, 6.5 (2.2 to 8.7)%, and 10.0 (8.1 to 11.7)% of the administered 51Cr-labeled EDTA, respectively. Urine passed during the first 6 hours contained, on average, 67 (54 to 77)% of the total 24-hour urine recovery.

Conclusions

6-hour urinary recovery of 51Cr-EDTA provides a potential alternative to 24-hour recovery. This shorter collection period may more specifically reflect small intestinal permeability. (Am J Vet Res 1998; 59:1113-1115)
Role of horn flies (Haematobia irritans) in Staphylococcus aureus-induced mastitis in dairy heifers
Authors: Owens W. E. , Oliver S. P. , Gillespie B. E. , Ray C. H. , Nickerson S. C.
Published: January 2024

Objective

To determine whether Staphylococcus aureus can colonize in horn flies and whether colonization is sufficiently persistent for transmission of the organism to cows by flies.

Animals

2 Jersey heifers exposed to infected horn flies.

Procedure

Staphylococcus aureus was allowed to colonize in horn flies, and duration of colonization was determined. Flies with colonized S aureus were allowed to feed on teats of uninfected heifers to determine whether intramammary infection could be transmitted from fly to heifer. Scab material from naturally infected heifers was submitted for bacteriologic culture to determine whether Saureus was present and whether scabs could serve as a possible source of S aureus for flies.

Results

Staphylococcus aureus colonized in horn flies and remained for up to 96 hours after exposure. Exposure of teats of uninfected heifers to horn flies colonized with S aureus resulted in intrammmary infection in 3 of 4 exposed teats. Culture of scab material from teats of naturally infected heifers revealed high concentration of S aureus (> 107 colony-forming units/mg), and flies without previously colonized S aureus were allowed to feed on scabs; Saureus colonized in them just as readily as it did in flies that had fed on experimentally infected blood.

Conclusions

Horn flies are capable of transmitting Saureus-induced intramammary infection to heifers, and scabs on teats are a potential source of S aureus. Fly control on dairy cows in herds with known Saureus problems is recommended as a method to help prevent these infections. (Am J Vet Res 1998;59: 1122-1124)
Cardiorespiratory and anesthetic effects of propofol and thiopental in dogs
Authors: Quandt Jane E. , Robinson Elaine P. , Rivers William J. , Raffe Marc R.
Published: January 2024

Objective

To compare cardiorespiratory and anesthesia effects of IV administered propofol and thiopental in dogs.

Animals

6 healthy mixed-breed dogs.

Procedure

Each dog was anesthetized with isoflurane, then a thermistor catheter was inserted in the pulmonary artery. After a minimum of 2.5 hours of recovery, a catheter was placed in a cephalic vein for administration of lactated Ringer's solution and drugs. Propofol (8 mg/kg of body weight) or thiopental (19.4 mg/kg) was administered to each dog in a randomized crossover design study. All dogs were intubated and allowed to breathe 100% oxygen spontaneously. Heart rate and rhythm; systolic, diastolic, and mean arterial blood pressures; respiratory rate; end-tidal carbon dioxide concentration; tidal volume; and reflexes (toe web pinch, palpebral response, and jaw tone) were measured before and every 2 minutes for the first 10 minutes, then at 15, 30, and 60 minutes after drug administration. Cardiac output was determined at 0, 2, 6, 10, 15, 30, and 60 minutes, and blood samples were collected at 0, 2, 10, and 30 minutes. Time to endotracheal extubation, head lift, and ability to sit sternally and walk unaided were recorded.

Results

3 of 6 dogs in each group were apneic after drug administration. Reflexes were decreased similarly for both anesthetic agents, but were not completely lost. Time to sternal position and walking unaided were significantly shorter in response to propofol.

Conclusion

Anesthesia was rapid; however, respiratory depression and apnea were major adverse effects associated with propofol and thiopental. Propofol has the advantage of inducing rapid, coordinated anesthesia recovery. (Am J Vet Res 1998;59:1137-1143)
Cloning and expression of porcine recombinant soluble tumor necrosis factor receptor 1
Authors: Boury Nancy Maroushek , Bosworth Brad T. , Stabel Thomas J. , Kehrli Marcus E. , Taylor Michael J.
Published: January 2024

Objective

To clone, sequence, and express porcine recombinant soluble tumor necrosis factor receptor 1 (sTNFR1).

Procedure

A polymerase chain reaction (PCR)-based library enrichment technique was used to isolate a fragment of porcine TNFR1. The mature extracellular domain of porcine TNFR1 was subcloned into an expression vector and expressed in Escherichia coli as a fusion protein. Protein product was purified by immunoaffinity chromatography, using a commercially available affinity gel specific for the marker peptide of the fusion protein. The bioactivity of the purified protein was tested for its ability to inhibit TNF-mediated cytotoxicity in a PK(15) bioassay.

Results

A 927-base pair fragment of porcine TNFR1 encoding the entire extracellular and transmembrane domains, as well as 75 amino acids of the cytoplasmic domain, was isolated from a porcine lung cDNA library. The extracellular domain was expressed as a soluble TNFR1 fusion protein with a yield of 120 to 150 μg/L of culture. Affinity-purified porcine sTNFR1 was able to inhibit TNF-mediated cytotoxicity of porcine PK(15) cells in dose-dependent manner.

Conclusions

Porcine recombinant sTNFR1 inhibits TNF bioactivity in vitro. This recombinant protein will be useful for developing TNFR1 antibodies and studying the roles of TNF and TNFR1 in the pathogenesis of infectious diseases in swine. (Am J Vet Res 1998;59:1317–1322)
Reference values for selected hematologic and biochemical variables in Holstein bulls of various ages
Authors: Monke Donald R. , Kociba Gary J. , DeJarnette Mel , Anderson David E. , Ayars William H.
Published: January 2024

Objective

To determine reference ranges for hematologic and serum biochemical variables of bulls residing at an artificial insemination center.

Animals

225 healthy Holstein bulls categorized by age into yearling, intermediate age, and adult groups.

Procedure

Hematologic and serum biochemical analyses were performed on 1 blood and 1 serum sample from each bull.

Results

Significant differences associated with age were identified for 25 of 33 variables. Serum creatinine concentration for clinically normal adult bulls (2.44 ± 0.33 mg/dl) was higher than previously reported reference values for adult cattle. There was a reversal of the segmented neutrophil-to-lymphocyte ratio between yearling (0.85:1) and adult (2.6:1) bulls. This was associated with a significant and marked decrease in absolute numbers of lymphocytes per microliter between yearling (5,801 ± 1,683) and adult (1,307 ± 509) bulls.

Clinical Relevance

Reference values for selected clinicopathologic variables were generated from the data. (Am J Vet Res 1998;59:1386–1391)
Evaluation of biopsy specimens obtained during thoracoscopy from lungs of clinically normal dogs
Authors: Faunt Karen K. , Jones Brent D. , Turk Jim R. , Cohn Leah A. , Dodam John R.
Published: January 2024

Objective

To determine whether lung biopsy specimens obtained during thoracoscopy, using a commercially available ligature, can provide an adequate amount of tissue for histologic evaluation and to characterize changes in the lungs and thoracic cavity that result from the procedure.

Animals

6 mixed-breed dogs.

Procedure

All dogs underwent 2 anesthetic episodes. The first anesthetic episode was a sham procedure. During the second anesthetic episode, each dog underwent a thoracoscopic procedure to obtain a lung biopsy specimen, using a commercially available ligature. Biopsy specimens were assessed subjectively by means of histologic evaluation. Samples for arterial blood gas analysis were obtained, and thoracic radiography was performed after surgery. Dogs were evaluated daily for 14 days after thoracoscopy and then were euthanatized. Tissues were evaluated grossly and histologically.

Results

Excellent intraoperative visibility and biopsy specimens adequate for histologic evaluation were obtained from all dogs. Significant differences were not found between arterial blood gas values of sham- and thoracoscopy-treated dogs for samples obtained 0.25, 2, and 24 hours after extubation. Examination of thoracic radiographs obtained 2 and 24 hours after thoracoscopy revealed minimal localized pathologic changes. All dogs were clinically normal 24 hours after thoracoscopy, and major postoperative complications were not detected. Gross and histologic findings of specimens obtained during necropsy revealed changes localized to biopsy and trocar sites.

Conclusions

Thoracoscopic placement of ligatures allowed procurement of lung lobe biopsy specimens from clinically normal dogs without complications.

Clinical Relevance

This procedure may provide a safe and minimally invasive means of obtaining lung biopsy specimens from clinically affected dogs. (Am J Vet Res 1998;59:1499–1502)
Technique of, and complications attributable to, repeated hyperosmotic blood-brain barrier disruption in dogs
Authors: Culver Britt , Inzana Karen , Jones Jeryl , Troy Gregory , Kroll Robert , Culver Brenda , Jortner Bernard
Published: January 2024

Objective

To design a repeatable technique for reversible, hyperosmotic blood-brain barrier disruption (BBBD) in dogs and evaluate clinical effects of multiple BBBD.

Animals

10 healthy adult dogs.

Procedure

Using fluoroscopic guidance, an arterial catheter was directed into the internal carotid artery via the femoral artery of 10 dogs. Blood-brain barrier disruption was achieved in 5 dogs, using intracarotid infusion of mannitol. Five control dogs received only saline solution. After recovery, dogs were monitored for clinical signs of disease before a second, nonsurvival procedure was performed 2 to 3 weeks later. BBBD was estimated, using computed tomographic (CT) densitometry values, as well as Evan’s blue dye staining on necropsy specimens.

Results

Seven dogs completed the entire study. Two treatment dogs were lost after the first infusion because of deteriorating neurologic function attributed to CNS edema and increased intracranial pressure. One control dog was lost because of vessel wall damage during catheterization. The remaining dogs had only transient neurologic, ocular, and vasculature injuries. Successful BBBD was documented in all treated dogs by use of CT and Evan’s blue dye evaluation.

Conclusion

Repeated catheterization of the internal carotid artery and disruption of the blood-brain barrier is possible in dogs.

Clinical Relevance

Refinement of this technique would be useful not only for improved delivery of chemotherapeutic agents in patients with brain tumors, but also would allow further investigation of new treatments involving genetically engineered retroviruses and monoclonal antibodies. (Am J Vet Res 1998;59:1503–1510)
Determination of skin concentrations of enrofloxacin in dogs with pyoderma
Authors: DeManuelle T. C. , Ihrke P. J. , Brandt C. M. , Kass P. H. , Vulliet P. R.
Published: January 2024

Objective

To compare serum and skin concentrations of enrofloxacin in dogs with pyoderma with those of clinically normal dogs and to evaluate concentrations in dogs with superficial versus deep pyoderma.

Animals

16 clinically normal dogs and 16 dogs with pyoderma.

Procedure

Enrofloxacin (approx 5 mg/kg of body weight, PO) was administered daily to all dogs. Serum samples and skin biopsy specimens were obtained on day 1 at 3 hours after drug administration and on day 3 immediately before and 3 hours after drug administration. Samples and specimens were assayed by high-performance liquid chromatography. Morphometric analysis was performed on skin biopsy specimens to determine correlation between inflammatory cells and peak tissue enrofloxacin concentration on day 1.

Results

Morphometric analysis revealed high correlation between dermal inflammatory cell count and drug concentration in dogs with pyoderma.

Conclusions

At mean dosage of 5 mg/kg once daily, enrofloxacin tissue concentrations were significantly greater in dogs with pyoderma at 3 hours after pill administration. Enrofloxacin tissue concentration on day 3 at 3 hours after pill administration was 12.4 times the 90% minimum inhibitory concentration of enrofloxacin for Staphylococcus intermedius.

Clinical Relevance

In dogs with pyoderma, therapeutic tissue concentrations of enrofloxacin are reached as early as 3 hours after drug administration. (Am J Vet Res 1998;59:1599-1604)
Effect of timing and route of administration of furosemide on pulmonary hemorrhage and pulmonary arterial pressure in exercising Thoroughbred racehorses
Authors: Lester Guy , Clark Carol , Rice Brett , Steible-Hartless Christine , Vetro-Widenhouse Tamara
Published: January 2024

Objectives

To examine effect of pre-exercise administration of furosemide (FUR) on mean pulmonary arterial pressure (PAP) during work and RBC concentration in bronchoalveolar lavage fluid (BALF) collected 40 minutes after exercise.

Animals

10 adult Thoroughbreds.

Procedure

A modified 10 × 10 crossover design comprising 10 horses during 10 weeks was used. Each horse received each of 5 treatments twice. Treatment structure included a control plus a 2 × 2 factorial and consisted of the following: A, control; B, FUR, 250 mg, IV, 30 minutes before exercise; C, FUR, 250 mg, IV, 240 minutes before exercise; D, FUR, 250 mg, nebulized, 30 minutes before exercise; and E, FUR, 250 mg, nebulized, 240 minutes before exercise. Mean PAP data were collected, and each horse, after a 500-m warm-up, was galloped at maximal speed for 1,600 m. BALF RBC concentration was determined by hemocytometer.

Results

Interaction between treatment method and time of administration was significant (P = 0.04). Treatment B resulted in significantly (P = 0.01) lower BALF RBC concentration than did treatment C. Only BALF RBC count after treatment B was significantly lower than the control value. Horses that received FUR IV had significantly lower peak mean PAP than did those that received the drug by nebulization, regardless of administration time. Only treatment B resulted in peak mean PAP that was significantly lower than that of control. Exercise time was not influenced by treatment.

Conclusions

FUR, administered IV 30 minutes before exercise, significantly reduced peak mean PAP and BALF RBC concentration. (Am J Vet Res 1999; 60:22–28)
Histopathologic alterations induced in the lungs of sheep by use of α2-adrenergic receptor agonists
Authors: Celly Chander S. , Atwal Onkar S. , McDonell Wayne N. , Black William D.
Published: January 2024

Objective

To study effects of central- and peripheral-acting α2-adrenergic receptor agonists on lung parenchyma, platelets, and pulmonary intravascular macrophages (PIM) of sheep.

Animals

12 healthy mature female sheep.

Procedure

Group-1 (control, n = 2) sheep received 5 ml of physiologic saline solution IV and were euthanatized 3 minutes later. Sheep of group 2 (n = 8) received xylazine (150 µg/kg of body weight, IV), then 2 sheep each were euthanatized 3, 10, or 60 minutes, or 12 hours later. Sheep (n = 2) of group 3 were given ST-91 (30 µg/kg, IV), then were euthanatized 3 minutes later. Immediately after euthanasia, the lungs were fixed intratracheally and tissue was obtained for light and electron microscopy after 1 hour.

Results

Pulmonary parenchymal damage or morphologic alterations in PIM and platelets were not evident in control sheep. Three minutes after xylazine administration, morphologic changes in PIM were appreciable. After 10 minutes, extensive damage to the capillary endothelium and alveolar type-I cells, intra-alveolar hemorrhage, and interstitial and alveolar edema were evident. Most PIM had complete internalization of the surface coat. Similar changes were seen 60 minutes after xylazine administration; however, by 12 hours, morphologic features of PIM and lung parenchyma were almost completely restored. Evidence of PIM activation, obvious damage to capillary endothelium, and extensive pulmonary edema also were evident 3 minutes after ST-91 administration.

Conclusions

Xylazine induces severe pulmonary parenchymal damage when administered at clinical sedative doses in sheep; morphologic changes in PIM within 3 minutes after administration of these drugs are substantial; and platelet aggregation is not apparent. (Am J Vet Res 1999;60:154-161)
Shedding of feline immunodeficiency virus in semen of domestic cats during acute infection
Authors: Jordan Holly L. , Liang Yinghua , Hudson Lola C. , Tompkins Wayne A.
Published: January 2024

Objective

To examine shedding of cell-free and cell-associated feline immunodeficiency virus (FIV) in semen of domestic cats during acute infection.

Animals

7 specific-pathogen-free sexually intact male cats.

Procedure

6 cats were inoculated IV with 5 × 106 50% tissue culture infective doses of FIV-NCSU1, and 1 cat served as an uninfected (control) cat. Infection was confirmed in the 6 cats. Periodically for up to 16 weeks after inoculation, cats were anesthetized and ejaculates obtained by use of electroejaculation. Virus was isolated from filtered seminal plasma and washed seminal cells by co-cultivation with a feline CD4+ T-cell line. Seminal cell lysates were also examined for a 582-base pair segment of FIV gag provirus DNA, using a nested polymerase chain reaction amplification.

Results

During the acute phase of FIV infection, virus was evident in semen of 5 inoculated cats. Five cats had virus-positive seminal plasma and 3 had virus-positive cellular constituents during the study. Virus was isolated from 8/22 (36%) seminal plasma samples and 2/17 (18%) seminal cell specimens. Provirus DNA was detected in 5/24 (21%) seminal cell lysates. Cell-free virus was isolated as early as 6 weeks after inoculation, whereas cell-associated virus was isolated as early as 12 weeks after inoculation. Provirus DNA was detected in seminal cells from one cat as early as 1 week after inoculation.

Conclusions and Clinical Relevance

Cell-free and cell-associated FIV are shed in semen of cats early during the course of infection. Samples obtained before seroconversion may contain virus. Virus shedding in ejaculates varies between and within cats during acute infection. (Am J Vet Res 1999;60:211-215.)
Identification and clinical assessment of suspected vaccine-related field strains of porcine reproductive and respiratory syndrome virus
Authors: Mengeling William L. , Vorwald Ann C. , Lager Kelly M. , Clouser Deborah F. , Wesley Ronald D.
Published: January 2024

Objective

To determine the origin and clinical relevance of selected strains of porcine reproductive and respiratory syndrome (PARS) virus (PRRSV).

Animals

38 pigs without antibodies for PRRSV.

Procedure

A seemingly uncommon restriction endonuclease digestion site in a commercially available vaccine strain of attenuated PRRSV was tested for its stability and prevalence under defined conditions. Selected field strains of PRRSV, with or without the restriction-site marker, were subsequently tested in pigs for virulence and for their ability to replicate competitively in pigs simultaneously given the vaccine.

Results

Under experimental conditions, the restriction-site marker was stable during long-term infection of pigs. It was not detected in any of the 25 field strains of PRRSV that were isolated before use of the vaccine or 21 of 25 field strains that were isolated after use of the vaccine but that, on the basis of previous testing, were believed unrelated to the vaccine strain. Conversely, it was detected in 24 of 25 field strains that were isolated after use of the vaccine and that, on the basis of previous testing, were believed to be direct-line descendants of the vaccine strain. Putative vaccine-related strains caused more pronounced pathologic changes than did the vaccine strain alone, and they predominated during replication in pigs also given the vaccine strain.

Conclusions

In some swine herds, the vaccine strain may have persisted and mutated to a less attenuated form.

Clinical Relevance

The potential for persistence and mutation of specific strains of virus should be an important consideration when designing vaccination programs involving attenuated PRRSV. (Am J Vet Res 1999;60:334–340)
Polymerase chain reaction techniques for differentiating cytotoxic and noncytotoxic Pasteurella trehalosi from Rocky Mountain bighorn sheep
Authors: Green Alice L. , DuTeau Nancy M. , Miller Michael W. , Triantis Joni M. , Salman M. D.
Published: January 2024

Objective

To evaluate 2 polymerase chain reaction (PCR)-based methods for differentiating cytotoxic and noncytotoxic Pasteurella trehalosi from Rocky Mountain bighorn sheep (Ovis canadensis canadensis).

Sample Population

23 isolates of P trehalosi from bighorn sheep in Colorado, including 18 from free-ranging herds and 5 from a captive herd.

Procedure

Using a sequence of the leukotoxin gene region of P haemolytica serotype 1, 7 PCR primers were designed. A PCR amplification was performed on a sample of bacterial cell suspensions from pure cultures of P trehalosi with known in vitro cytotoxic effects. The 2 most promising primer pairs were used in a study of 23 P trehalosi isolates. Results were analyzed for association with cytotoxicity and 3 distinct ribotypes (ECO, ACO, and BCO).

Results

Significant associations were observed between in vitro cytotoxicity and PCR results for coding region, between ribotype ECO classification and PCR results for coding region, and between ribotype ECO classification and PCR results for promoter region. There was a negative association between ribotype ACO classification and PCR results for coding and promoter regions.

Conclusions and Clinical Relevance

The PCR for the leukotoxin A coding region may be useful in differentiating cytotoxic from noncytotoxic P trehalosi isolates recovered from bighorn sheep. It may be useful for studying epidemiologic features of pasteurellosis in bighorn sheep and for designing vaccines to protect wild sheep against pneumonia caused by P trehalosi and P haemolytica. (Am J Vet Res 1999;60:583–588)
Effect of exercise on the immune response of young and old horses
Authors: Horohov David W. , Dimock Abigail , Guirnalda Patrick , Folsom Robert W. , McKeever Kenneth H. , Malinowski Karyn
Published: January 2024

Objective

To compare exercise-induced immune modulation in young and older horses.

Animals

6 young and 6 aged horses that were vaccinated against equine influenza virus.

Procedure

Venous blood samples were collected for immunologic assessment before and immediately after exercise at targeted heart rates and after exercise for determination of plasma lactate and cortisol concentrations. Mononuclear cells were assayed for lymphoproliferative responses and incubated with interieukin-2 (IL-2) to induce lymphokine-activated killer (LAK) cells. Antibodies to equine influenza virus were measured.

Results

Older horses had significantly lower proliferative responses to mitogens than younger horses prior to exercise. Exercise caused a significant decrease in lymphoproliferative response of younger horses, but not of older horses. Activity of LAK cells increased slightly with exercise intensity in younger horses. Cortisol concentrations increased in both groups after exercise; younger horses had higher concentrations after exercise at heart rates of 180 and 200 beats/min than those of older horses. Plasma lactate concentrations increased with exercise intensity but there were no differences between older and younger horses. Older horses had lower antibody titers to equine influenza virus than younger horses. Exercise did not affect antibody titers.

Conclusion

Although lymphoproliferative responses and antibody titers of older horses were less than those of younger horses, older horses were more resistant to exercise-induced changes in immune function, possibly because of lower cortisol concentrations.

Clinical Relevance

Stress and aging are known to affect immune function. Older horses had reduced immune function, but were more resistant to exercise-induced immune suppression than younger horses. (Am J Vet Res 1999;60:643–647)
Myeloperoxidase activity of the large intestine in an equine model of acute colitis
Authors: McConnico Rebecca S. , Weinstock Daniel , Poston Mary Elizabeth , Roberts Malcolm C.
Published: January 2024

Objective

To determine whether quantification of myeloperoxidase (MPO) activity could be a useful laboratory technique to detect granulocyte infiltration in equine intestinal tissues.

Sample Population

Intestinal tissue (inflamed or healthy) collected from 16 age- and sex-matched Shetland Ponies.

Procedure

Intestinal tissue MPO activity was determined, and histologic assessment of adjacent specimens from healthy and inflamed intestine was done.

Results

Intestinal tissue MPO activity and histopathologic score increased with time after castor oil challenge and peaked at 16 hours in an equine diarrhea model in which individual ponies provided their own control tissues.

Conclusions

Intestinal tissue inflammation scores correlated positively with tissue MPO activity in adjacent specimens.

Clinical Relevance

Tissue MPO assay may be a useful laboratory tool to quantify intestinal mucosal inflammation in ponies. (Am J Vet Res 1999;60:807–813)
Influence of feeding on serum feline trypsin-like immunoreactivity
Authors: Steiner Jörg M. , Williams David A.
Published: January 2024

Objective

To determine whether feeding causes a change in feline trypsin-like immunoreactivity (fTLI) in serum from healthy cats.

Animals

6 healthy domestic shorthair cats.

Procedures

For the first 12 days of the study, 3 cats were fed a high-protein, high-fat (diet 1), and the other 3 were fed a maintenance (diet 2). On day 12, diets were switched, and cats were fed the other diet for the remaining 12 days of the study. On days 11 and 23, food was withheld for 24 hours, and baseline serum fTLI was measured. Cats were offered food equivalent to half their daily caloric maintenance requirements, and serum fTLI was measured 1, 2, 4, 6, 12, and 24 hours later. Uneaten food was removed after 1 hour.

Results

Overall mean ± SD serum fTLI was 22.7 ± 5.8 µg/L when cats were fed diet 1 and 21.1 ± 5.0 µg/L when cats were fed diet 2. There was no significant difference in serum fTLI over time or between diets. However, there was a statistically significant, but clinically unimportant (mean increase, 1.7 µg/L), increase in serum fTLI, compared with baseline values, 1 hour after cats were fed diet 2 but not when cats were fed diet 1.

Conclusions and Clinical Relevance

A maintenance diet may cause a clinically unimportant increase in serum fTLI 1 hour after feeding in healthy cats. Results suggest that for healthy cats, it is not necessary to withhold food before collecting samples for determination of fTLI in serum. Whether feeding changes fTLI in serum from cats with disorders of the exocrine portion of the pancreas remains to be determined. (Am J Vet Res 1999;60:895–897)
Familial clustering and risk analysis for fragmented coronoid process and elbow joint incongruity in Bernese Mountain Dogs in The Netherlands
Authors: Ubbink Geert J. , Hazewinkel Herman A. W. , van de Broek Jan , Rothuizen Jan
Published: January 2024

Objective

To analyze familial clustering and genetic risk for various forms of elbow dysplasia (ED) in Bernese Mountain Dogs (BMD) in The Netherlands and define possible means to select against ED.

Animals

98 BMD born in 1992 and 64 BMD born in 1995.

Procedure

Dogs were examined radiographically when 12 to 18 months old. The population was resolved into familial clusters, and distribution of ED for the clusters was analyzed. Common ancestors associated with each form of ED were identified, and risk for having ED in the 64 offspring born in 1995 was calculated by relatedness to common ancestors. Risk was compared with radiographic outcome.

Results

The 2 forms of ED identified were fragmented coronoid process (FCP) and elbow joint incongruity (INC). Incidence of ED decreased from 63/98 (64%) in 1992 to 29/64 (45%) in 1995. None of the familial clusters was free of FCP or INC. Common ancestors associated with FCP differed from those associated with INC. There was more potential variation in risk for FCP and INC in the 64 offspring than was achieved by breeders, indicating a decrease in population heterogeneity.

Conclusions and Clinical Relevance

FCP and INC had differing familial sources; thus, they most likely are different genetic traits. Although Incidence of ED decreased from 1992 through 1995, we did not detect variation among pedigrees in genetic risk for ED remaining in the offspring born in 1995; thus, selection among families cannot further improve ED health status of BMD in The Netherlands. Phenotypic selection within families remains the only alternative. [Am J Vet Res 1999;60:1082-1087)
Effects of intravenously administered yohimbine on antinociceptive, cardiorespiratory, and postural changes induced by epidural administration of detomidine hydrochloride solution to healthy mares
Authors: Skarda Roman T. , Muir William W.
Published: January 2024

Objective

To determine effects of IV administered yohimbine on perineal analgesia, cardiovascular and respiratory activity, and head and pelvic limb position in healthy mares following epidural administration of detomidine hydrochloride solution.

Animals

8 healthy mares.

Procedure

Each mare received detomidine hydrochloride (0.06 mg/kg of body weight), administered in the caudal epidural space, followed 61 minutes later by yohimbine (0.05 mg/kg; test) or sterile saline (0.9% NaCl) solution (control), administered IV, in a randomized, crossover study design with ≥ 2 weeks between treatments. Analgesia was determined by lack of sensory perception to electrical stimulation of perineal dermatomes and needle-prick stimulation of coccygeal to 15th thoracic dermatomes. Arterial pH, Paco2, Pao2, heart and respiratory rates, rectal temperature, arterial blood pressure, and cardiac output were determined, and mares were observed for sweating and urination. Mean scores obtained for test and control groups were compared.

Results

Intravenously administered yohimbine significantly reduced mean scores of detomidine-induced perineal analgesia, head ptosis, changes in pelvic limb position, and sweating and diuresis; antagonized detomidine-induced decreases in heart rate and cardiac output; but did not affect detomidine-induced decrease in respiratory rate.

Conclusions and Clinical Relevance

Most effects of epidurally administered detomidine, except bradypnea, were antagonized by yohimbine, suggesting that detomidine may influence respiratory rate by mechanisms other than stimulation of α2-adrenoceptors, or that yohimbine induces respiratory depressant effects. Yohimbine may be an effective α2-adrenoceptor antagonist for all but respiratory depression following epidural administration of detomidine to mares. (Am J Vet Res 1999;60:1262–1270)
Ranitidine bismuth citrate and clarithromycin, alone or in combination, for eradication of Helicobacter mustelae infection in ferrets
Authors: Marini Robert P. , Fox James G. , Taylor Nancy S. , Yan Lili , McColm Andrew A. , Williamson Russell
Published: January 2024

Objective

To determine whether ranitidine bismuth citrate, clarithromycin, or a combination of ranitidine bismuth citrate and clarithromycin would be efficacious in eradication of Helicobacter mustelae infection in ferrets.

Animals

60 seven-month-old ferrets.

Procedure

To determine dosages of clarithromycin and ranitidine bismuth citrate that would suppress growth of, but not eradicate infection with, H mustelae, ferrets (n = 6/group) were treated PO with clarithromycin or ranitidine bismuth citrate at various dosages. Efficacy of treatment was then determined by treating ferrets with clarithromycin alone, ranitidine bismuth citrate alone, or clarithromycin and ranitidine bismuth citrate. Gastric biopsy specimens were obtained before, during, and at various times after treatment and submitted for quantitative bacterial culture and histologic evaluation. Minimum concentrations of clarithromycin that inhibited 90% of the growth of isolates obtained before and after treatment were determined.

Results

Dosages of clarithromycin and ranitidine bismuth citrate that suppressed growth of H mustelae were 12.5 and 24 mg/kg of body weight, PO, every 8 hours, respectively. Infection was not eradicated in ferrets treated with ranitidine bismuth citrate alone but was eradicated in all 6 ferrets treated with clarithromycin and ranitidine bismuth citrate and in 4 of 6 treated with clarithromycin alone. A decrease in susceptibility to clarithromycin was detected for H mustelae isolates obtained after treatment. Mild or moderate antral gastritis was observed even in ferrets from which infection was eradicated.

Conclusions and Clinical Relevance

A combination of ranitidine bismuth citrate and clarithromycin was efficacious in eradicating H mustelae infection from ferrets. (Am J Vet Res 1999;60:1280–1286)
Radiographic, biomechanical, and pathologic effects of hemoglobin glutamer-200 in dogs undergoing cemented total hip arthroplasty
Authors: Braden Terrance D. , Tvedten Harold W. , DeCamp Charles E. , Turner Thomas M. , Hughes George S. , Rentko Virginia T.
Published: January 2024

Objective

To determine whether use of hemoglobin glutamer-200 (bovine) as a partial blood volume replacement in dogs undergoing cemented total hip replacement caused any deleterious effects on the bone-cement or cement-prosthesis interface, exerted any deleterious effects on body organs, or caused any complications during the anesthetic, immediate recovery, or long-term recovery period.

Animals

9 adult dogs.

Methods

Dogs were anesthetized, and 15% of the blood volume was removed. Simultaneously, lactated Ringer's solution was infused, and 6 dogs were given hemoglobin glutamer (1 g/kg of body weight, IV). Unilateral total hip replacement was performed. Limb use was assessed visually, and force-plate and radiographic evaluations were performed before, and 8 weeks after, surgery. Eight weeks after surgery, dogs were euthanatized, necropsies were performed, and prosthetic component pullout forces were determined.

Results

There were no significant differences between treated and control dogs in regard to biomechanical (visual assessment of gait, force-plate analysis, femoral and acetabular component pullout forces) and pathologic evaluations (physical examination, CBC, serum biochemical analyses, necropsy, and histologic evaluations). Radiographic signs of loosening of the femoral component were seen in 4 dogs treated with hemoglobin glutamer.

Conclusions and Clinical Relevance

Administration of hemoglobin glutamer as a blood substitute did not appear to have any deleterious effects in dogs undergoing total hip arthroplasty. The radiographic findings, which were discordant with the biomechanical results, merit further investigation. (Am J Vet Res 1999;60:1337–1340)
Effects of a controlled-release cisplatin delivery system used after resection of mammary carcinoma in mice
Authors: Ehrhart Nicole , Dernell William S. , Ehrhart E.J. , Hutchison Jennifer M. , Douple Evan B. , Brekke John H. , Straw Rodney C. , Withrow Stephen J.
Published: January 2024

Objective

To evaluate efficacy of a controlled-release cisplatin delivery system, used after marginal resection of mammary carcinoma (ie, resection of grossly evident tumor) in mice, to prevent tumor regrowth and metastasis.

Animals

42 female C3H-HeJ mice.

Procedure

Mice were inoculated with mammary carcinoma cells. Between 2 and 6 days later, tumors were marginally resected and mice were assigned to 1 of 3 groups: no treatment (control; n = 14), cisplatin administered intraperitoneally (IP cisplatin; 14), and cisplatin delivered by use of an open-cell polylactic acid system placed within the tumor bed (slow-release cisplatin; 14). Tumor regrowth was measured daily. Mice were euthanatized 14 days after surgery, and complete necropsies were performed.

Results

Tumor regrowth was not detected in the slow-release cisplatin group; however, tumor regrowth was detected in 7 of 14 mice in the IP cisplatin group and 14 of 14 mice in the control group. Median (± SD) number of days to tumor regrowth was 13.5 ± 0.64 and 7.79 ± 0.87 in the IP cisplatin and control groups, respectively. Mice in the IP cisplatin group had significantly delayed tumor regrowth, compared with control mice. Metastases to lungs were detected in 8 of 14 control mice but were not detected in mice in either cisplatin treatment group.

Conclusions and Clinical Relevance

The open-cell polylactic acid with cisplatin delivery system was successful in delaying local tumor regrowth and metastasis in mice with marginally resected mammary carcinoma. Use of a controlled-release cisplatin delivery system may be an effective adjunct treatment following excision of mammary carcinoma in humans and other animals. (Am J Vet Res 1999;60:1347–1351)