bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of heartworm infection on in vitro contractile responses of canine pulmonary artery and vein
Authors: Maksimowich Daria S. , Mupanomunda Maria , Williams Jeffrey F. , Kaiser Lana
Published: January 2024

Objective

To test the effect of heartworm infection on agonist-induced constriction of canine pulmonary artery and vein in vitro.

Procedure

Cumulative concentration-response relations to norepinephrine, serotonin, histamine, prostaglandin F2α, and the thromboxane A2 analog U-44069 were determined, using isolated rings of pulmonary artery and vein from control and heartworm-infected dogs. To determine the role of endothelial cells in histamine constriction, some rings were denuded of endothelial cells in both artery and vein.

Animals

Noninfected control and heartworm-infected dogs.

Results

There was no difference in constriction response to norepinephrine, serotonin, prostaglandin F2α, or U44069 of pulmonary artery or vein from control or heartworm-infected dogs. Histamine-induced constriction of pulmonary artery from heartworm-infected dogs was not different from control values, however, when endothelial cells were removed from control, but not heartworm-infected pulmonary artery, histamine-induced constriction was enhanced. Histamine-induced constriction of pulmonary vein from heartworm-infected dogs was significantly depressed, compared with that of control pulmonary vein. However, removal of endothelial cells in pulmonary vein from heartworm-infected, but not control dogs significantly increased constriction.

Conclusion

Heartworm infection alters histamine-induced constriction responses of pulmonary artery and vein. These changes may reflect high circulating histamine concentrations in heartworm-infected dogs, compared with that in controls. Increased circulating histamine concentrations in vivo could bring about decreased sensitivity of histamine receptors or decreases in the number of receptors expressed.

Clinical Relevance

Mast cells and histamine may be important factors in altered endothelium-mediated responses associated with heartworm disease. (Am J Vet Res 1997;58:394–397)
Comparison of intratumoral administration of cisplatin versus bleomycin for treatment of periocular squamous cell carcinomas in horses
Authors: Théon A. P. , Pascoe J. R. , Madigan J. E. , Carlson G. , Metzger L.
Published: January 2024

Objective

To compare therapeutic benefits of intratumoral administration of cisplatin and bleomycin for squamous cell carcinoma of the eyelids in horses.

Animals

25 horses with 27 T2-stage periocular squamous cell carcinomas.

Procedure

Horses were treated 4 times at 2-week intervals with a slow-release formulation of cisplatin (1 mg/cm3 of tissue) or bleomycin (1 IU/cm3 of tissue). A two-stage design was used to minimize the sample size in each treatment arm.

Results

The local control rate at 1 year for lesions treated with cisplatin was 93 ± 6%, and with bleomycin was 78 ± 10%. Difference in local control duration between the 2 treatment groups was not significantly different. A high tumor proliferative fraction index value was associated with a higher local (in-field) control rate, but also with a higher risk of marginal and regional recurrences. Tumors with a low proliferative fraction index value (< 28%) had 9.5-times higher (P = 0.0411) risk of recurrence than those with a high index value. Local acute reactions were similar in the 2 treatment groups, and chronic reactions were not observed.

Conclusions

Cisplatin and bleomycin were effective anticancer agents for carcinoma of the eyelid in horses. Based on therapeutic benefit and treatment cost, cisplatin was found to be a better choice for intratumoral chemotherapy of eyelid carcinomas.

Clinical Relevance

Results of this study confirm the value of intratumoral chemotherapy, using cisplatin, for treatment of cutaneous squamous cell carcinomas in horses. (Am J Vet Res 1997;58:431–436)
Effects of three sedative protocols on glomerular filtration rate in clinically normal dogs
Authors: Newell Susan M. , Ko Jeff C. , Ginn Pamela E. , Heaton-Jones Terrell G. , Hyatt Debra A. , Cardwell Amy L. , Mauragis Danielle F. , Harrison Jay M.
Published: January 2024

Objective

To determine the effects of 3 sedative protocols (butorphanol and diazepam [BD] IV; acepromazine and butorphanol [AB] IV; diazepam and ketamine [DK] IV) on glomerular filtration rate (GFR) as measured by 99mTc DTPA nuclear scintigraphy and to compare them with GFR measured without sedation. Cardiovascular, respiratory, and sedative effects of each protocol also were measured.

Animals

12 adult male Walker Hounds.

Procedure

Systolic, diastolic, and mean arterial blood pressures and heart and respiratory rates were measured before, during, and after scintigraphic measurement of GFR.

Results

Difference in GFR was not significant between any of the sedative regimens and the control. The DK protocol caused significant increases in systolic, diastolic, and mean arterial blood pressure; compared with the AB and BD protocols, it caused significant increases in heart rate versus all protocols, and was associated with the lowest mean GFR (2.80 ml/min/kg of body weight). The AB protocol caused significant decreases in systolic, diastolic, and mean arterial blood pressures, compared with DK and the nonsedation protocols. Mean GFR for the BD protocol was 2.94 ml/min/kg, and was 3.13 ml/min/kg for the AB and the nonsedation protocols. The AB protocol provided the best sedation with minimal additional restraint required. The BD and nonsedation protocols often were associated with substantial dog movement. The DK protocol induced inadequate duration of immobilization (< 10 minutes) in some dogs and excitement in others.

Conclusion

GFR measurements obtained with any of the sedative protocols were not significantly different, compared with measurements in awake dogs. The AB protocol provides the best sedative effects and was associated with GFR values identical to those in awake dogs. Systemic hypotension caused by acepromazine did not decrease GFR in clinically normal dogs. (Am J Vet Res 1997;58:446–450)
Chromogranin A plasma concentration and expression in pancreatic islet cell tumors of dogs and cats
Authors: Myers Nathaniel C. , Andrews Gordon A. , Chard-Bergstrom Cindy
Published: January 2024

Objectives

To describe expression of the neuroendocrine marker chromogranin A (CgA) in canine and feline pancreatic islet cell tumors and their metastases, and to evaluate plasma CgA concentration in dogs and cats with insulinoma.

Sample Population

Paraffin-embedded tissues from 25 canine and 2 feline pancreatic islet cell tumors, 5 canine and 6 feline exocrine pancreatic tumors, and normal pancreatic tissue from 2 dogs and 2 cats. Heparinized plasma samples from 3 dogs and 2 cats diagnosed with insulinoma, and 10 control plasma samples from each species.

Procedure

Immunohistochemical analysis was performed on the 42 tissue specimens, using antisera against CgA, neuron-specific enolase, insulin, somatostatin, glucagon, and pancreatic polypeptide. The 25 plasma samples were evaluated, using a soluble-phase, double-antibody, equilibrium radioimmunoassay directed against the amino- and carboxy-terminal peptides of bovine CgA.

Results

Chromogranin A expression was found in 76% of canine and 2 of 2 feline pancreatic islet cell tumors. Of 7 animals with CgA immunoreactivity in primary tumors, 6 also had CgA immunostaining of metastatic lesions. Plasma CgA concentration in 2 dogs with insulinoma (0.9, 1.0 ng/ml) exceeded the reference range established for 10 clinically normal control dogs (0.50 ± 0.16 ng/ml). Feline plasma CgA samples had extensive nonspecific background immunoreactivity.

Conclusions

Chromogranin A is a useful immunohistochemical marker for pancreatic tumors of neuroendocrine origin and their metastases. Plasma CgA concentration determined by radioimmunoassay was high in 2 dogs with insulinoma.

Clinical Relevance

Immunohistochemical staining of tissues or cytologic specimens for CgA and/or neuron-specific enolase may help distinguish masses of unknown origin as neuroendocrine in nature. Increase in plasma CgA concentration may be useful diagnostically for animals with suspected neuroendocrine tumors. (Am J Vet Res1997;58:615–620)
Effect of sodium bicarbonate administration on renal function of horses
Authors: Rivas Luis J. , Hinchcliff Kenneth W. , Kohn Catherine W. , Sams Richard A. , Chew Dennis J.
Published: January 2024

Objectives

To describe changes in renal function of horses after oral and IV administration of sodium bicarbonate (NaHCO3) and to determine whether changes are dose dependent.

Animals

6 Standardbred mares.

Procedure

Blood and urine samples for determination of renal function were collected immediately before and at hourly intervals for 12 hours after administration of each of 3 oral doses (1,500, 1,000, and 250 mg/kg of body weight, in 3 L of water) and 1 IV dose (250 mg/kg, 5% solution) of NaHCO3, or water (3 L orally).

Results

NaHCO3 induced increases in urine flow; electrolyte-free water reabsorption; urine concentrations of sodium and bicarbonate; fractional excretion of sodium, potassium, chloride, and bicarbonate; urinary excretion and clearance of sodium and bicarbonate; urine pH and anion gap; and mean plasma concentration of antidiuretic hormone. NaHCO3 induced attenuation in reduction with time of urine excretion and clearance of potassium, chloride, and osmoles, and induced reduction in urine osmolality. Plasma aldosterone and atrial natriuretic peptide concentrations and glomerular filtration rate were not modified.

Conclusions

Renal responses to NaHCO3 load emphasize conservation of plasma volume and re-establishment of acid-base balance over control of hyperosmolality by means of diuresis, natriuresis, and increased bicarbonaturia. These responses imply a large fluid shift from the extravascular space to the vascular compartment, which was eliminated via diuresis, thus preventing hypervolemia. (Am J Vet Res 1997;58:664–671)
Profile of electrodiagnostic abnormalities in cats with GM1 gangliosidosis
Authors: Steiss J. E. , Baker H. J. , Braund K. G. , Cox N. R. , Wright J. C.
Published: January 2024

Objective

To determine which electrodiagnostic tests yield abnormal findings in cats with GM1 gangliosidosis, and to determine the approximate age of onset of electrodiagnostic abnormalities.

Animals

Cats (28 to 335 days old) affected with GM1 gangliosidosis (n = 11) and unaffected controls (n = 14).

Procedure

Cats were grouped by age: group 1, ≤ 90 days; group 2, 91 to 200 days; and group 3, > 200 days. Electrodiagnostic tests were conducted, including needle electromyography, motor and sensory nerve conduction velocity, spinal evoked potentials, and brainstem auditory evoked potentials. Results for control and affected cats were compared, using the general linear model for ANOVA and Scheffe's test for multiple comparisons.

Results

Needle electromyography did not reveal abnormal spontaneous activity in skeletal muscles of any cat; furthermore, statistical analysis did not indicate significant difference between affected and control groups for nerve conduction velocity, confirming that degeneration of peripheral nerve fibers is not a feature of this disease. However, spinal evoked potentials were abnormal in group-3 cats; conduction velocity within sensory pathways in the cranial part of the spinal cord was significantly slower in GM1-affected cats (P = 0.0002). Brainstem auditory evoked responses also were abnormal: wave V (generated in the region of the pons) had prolonged latency in cats of groups 2 and 3 (P = 0.0003 and 0.0001, respectively, at 90 decibels sound pressure level). In the oldest cats, latencies for earlier waves within the auditory pathway also were prolonged; wave I (generated by the cochlear nerve) was prolonged in group-3 cats (P = 0.0423).

Conclusion

Motor and sensory nerve conduction velocities remained within normal limits in GM1-affected cats. However, spinal evoked potentials indicated slowing in conduction velocity along the cranial part of the spinal cord in group 3 cats. Brainstem auditory evoked responses indicated prolonged latencies in cats of groups 2 and 3. (Am J Vet Res 1997;58:706–709)
Cortisol suppression in cats after induction of anesthesia with etomidate, compared with ketamine-diazepam combination
Authors: Moon Paula F.
Published: January 2024

Objective

To evaluate duration and magnitude of adrenocortical function suppression after administration of etomidate to cats.

Animals

15 purpose-bred, healthy cats.

Procedure

Cats were allotted to 2 groups. Anesthesia was induced with etomidate (ET, 2 mg/kg of body weight, IV; n = 8) or a mixture (KD, n = 7) of ketamine (5 mg/kg, IV) and diazepam (0.25 mg/kg, IV). Anesthesia was maintained with halothane in all cats for 2 hours. ACTH gel (2.2 U/kg, IM) was administered 30 minutes after anesthesia induction. Blood samples for cortisol assay were taken before anesthesia induction (T −30), and before (TO) and at 30, 60, 120, 180, 300, and 420 minutes after ACTH administration. Anesthesia was discontinued after the T120 sample was obtained.

Results

After anesthesia induction, median (interquartile range [Q1-Q3]) cortisol values were significantly lower in the ET group (4 [3 to 4] μg/dl) at TO, compared with T −30 values and with TO values in the KD group (5 [3 to 9] μg/dl). After ACTH administration, cortisol values in the ET group continued to decrease two- to threefold below T −30 values and remained decreased over the 2-hour anesthesia period. After ACTH administration, cortisol values increased twofold for 2 hours in the KD group, compared with T −30 values. One hour after anesthesia recovery, cortisol values in the ET group (3 [2 to 3] μg/dl) remained significantly lower than values in the KD group (9 [7 to 11] μg/dl) and preanesthesia values. By T300, both groups had cortisol concentration near 7 μg/dl, similar to preanesthesia values.

Conclusion

Induction of anesthesia with etomidate caused suppression of adrenocortical function during 2 hours of halothane anesthesia and 1 hour of recovery in cats. Cortisol concentration did not return to baseline until after 2 additional hours.

Clinical Relevance

Results from these healthy cats suggest profound suppression of important stress hormones after anesthesia induction with etomidate, use of which could put critically ill cats at further risk. (Am J Vet Res 1997;58:868–871)
Hormonal modulation of the physiologic responses of calves infected with Eimeria bovis
Authors: Heath H. L. , Blagburn B. L. , Elsasser T. H. , Pugh D. G. , Sanders L. G. , Sartin E. A. , Steele B. , Sartin J. L.
Published: January 2024

Objective

To determine whether an estradiol-progesterone (EP) growth implant would have an effect on febrile responses and on the catabolic component of Eimeria bovis infection.

Animals

27 Holstein bull calves.

Procedure

Calves were assigned to treatment groups as: control (n = 5), EP implant (EP, n = 5), E bovis-inoculated (coccidia: C, n = 7), pair fed (n = 4), or EP plus E bovis-inoculated coccidia (EP/C, n = 6) groups. Calves were provided subcutaneous EP implants at 8 weeks of age, and were inoculated with 2 × 105 oocysts of E bovis at 11 weeks of age. Body weight was measured on postinoculation day (PID) 0, 14, and 28. Rectal temperature and food intake were determined and fecal samples were collected daily from PID 15 to 28. Blood samples were collected on PID 24 for analysis of CD2+, CD4+, and CD8+ antigens and plasma insulin-like growth factor I concentration. Blood samples were collected at 15-minute intervals for measurement of pulsatile growth hormone release.

Results

Group-EP/C calves had fever for 2 days versus 5 days for group-C calves (P < 0.05). These calves had diarrhea for fewer days than did their group-C counterparts (P < 0.05). Fibrinogen and glucose values were high in group-C (P < 0.05) but not group-EP/C calves. The latter had positive weight gain from PID 14 to 28, whereas group-C calves had weight loss (P < 0.05). Plasma insulin-like growth factor I concentration was reduced by infection (P < 0.05). EP-treated noninfected calves had increased numbers of CD2+, CD4+, and CD8+ blood mononuclear cells (P < 0.05).

Conclusions

EP has a protective effect in calves infected with E bovis. This may relate to changes in immune function induced by EP.

Clinical Relevance

Treatment of calves with EP could offer some protection against the often severe wasting and debilitation associated with E bovis infection. (Am J Vet Res 1997;58:891–896)
Effect of combined administration of insulin-like growth factor and platelet-derived growth factor on the regeneration of transected and anastomosed sciatic nerve in rats
Authors: Welch Janet A. , Kraus Karl H. , Wells Michael R. , Blunt Dana G. , Weremowitz J.
Published: January 2024

Objective

To evaluate the efficacy of combined administration of platelet-derived growth factor (PDGF) and insulin-like growth factor (IGF-I) on the regeneration of transected and anastomosed sciatic nerves.

Animals

25 male Lewis rats.

Procedure

Transection and anastomosis was performed of the left sciatic nerve of all rats. At the time of surgery, treatment group rats received a combination of PDGF (0.75 μg) and IGF-I (1.5 μg) along with vehicle (2% methyl cellulose gel) at the anastomosis site. Control rats received vehicle alone. Evaluation consisted of motor evoked potentials and nerve conduction velocity, quantitative histologic examination, sciatic functional index, and visual assessment of repair organization (lesion scores).

Results

Significant differences in motor evoked potential latency, nerve conduction velocity, axon number, sciatic functional index, or lesion scores were not found between groups.

Conclusions

Combined administration of PDGF and IGF-I did not enhance peripheral nerve regeneration in a transection and anastomosis model as determined 6 weeks after surgery.

Clinical Relevance

These findings support the assumption that mechanical, versus trophic, effects predominate when nerve ends are closely apposed. (Am J Vet Res 1997;58:1033–1037)
Measurement of total body water content in horses, using deuterium oxide dilution
Authors: Andrews Frank M. , Nadeau Jenifer A. , Saabye Lisa , Saxton Arnold M.
Published: January 2024

Objective

To measure total body water (TBW) content in horses, using deuterium oxide (D20) dilution.

Animals

Six 8- to 10-year-old healthy untrained mixed-breed horses, weighing (mean ± SD) 503.4 ± 64.0 kg.

Procedure

After a 12-hour nonfeeding period, 6 horses were given D2O (0.14 g/kg of body weight) via nasogastric tube. Blood samples were collected from a preplaced indwelling jugular vein catheter prior to and 1 to 8, 10, 12, 14, and 24 hours after administration of D2O. Blood samples were centrifuged immediately, and plasma was collected and stored at −70 C until analysis. The D2O content in plasma was measured by zinc reduction to deuterium gas. The resulting gas was measured, using an isotope ratio mass spectrometer.

Results

Deuterium oxide was rapidly absorbed from the gastrointestinal tract of all horses, and reached peak (mean ± SD) plasma concentration (1,454.4 ± 163 delta D/ml or parts/thousand) 1 hour after administration. Plasma concentration decreased slowly during the next 2 to 3 hours, then remained statistically constant from 2 to 5 hours (early plateau phase) and 3 to 7 hours (late plateau phase) after administration. Mean ± SEM TBW content was 623.0 ± 2.2 ml/kg (62.3% of body weight) for the early plateau phase and 630.3 ± 2.2 ml/kg (63.0% of body weight) for the late plateau phase.

Conclusion

Deuterium oxide dilution appears to be of value for measurement of TBW content in horses, and has a 4-hour plateau effect. Equilibration of D2O with large intestinal water may be the reason for the prolonged equilibrium time and plateau effect seen in these horses.

Clinical Relevance

Deuterium oxide appears safe and efficacious for determining TBW content in horses and may be helpful for determining changes in TBW content during exercise and disease. (Am J Vet Res 1997;58:1060–1064)
Risk factors associated with the likelihood of leptospiral seropositivity in horses in the state of New York
Authors: Barwick Rachel S. , Mohammed Hussni O. , McDonough Patrick L. , White Maurice E.
Published: January 2024

Objective

To determine and quantify risk factors associated with exposure of horses to the following serovars of Leptospira interrogans: pomona, autumnalis, and bratislava.

Animals

2,551 horses were randomly selected from a target population during the period of May 1991 to August 1993.

Procedures

Blood was collected from the horses and tested for antibodies to serovars, using the microscopic agglutination test. A titer ≥ 1:100 indicated seropositivity. Information was collected on each horse, its environment, and each farm's management practices. Logistic regression analysis was used to develop a multidimensional indexing system for indices of exposure and to identify factors significantly associated with the risk of seropositivity. These indices were: 1) rodent exposure; 2) wildlife exposure; 3) soil and water; and 4) management.

Results

Rodent exposure index value was associated with the risk of exposure to all 3 serovars. Management index value was positively associated with the risk of exposure to serovars pomona and bratislava, but not with risk of exposure to serovar autumnalis. Soil and water index value had a positive association with risk of exposure to serovars pomona and autumnalis, but not to serovar bratislava. The wildlife index value and the population density of horses turned out together were associated with the risk of exposure to serovar autumnalis. Age of horse in years was associated nonlinearly (years2) and linearly (years) with the risk of exposure to serovars autumnalis and bratislava, and only linearly with the risk of exposure to serovar pomona.

Conclusion

Risk of seropositivity to the 3 serovars of L interrogans varies according to age, management practices, population density of horses turned out together, and the values of the rodent exposure, wildlife exposure, and soil and water indices. (Am J Vet Res 1997;58:1097–1103)
Pathogenesis of experimentally induced rabies in domestic ferrets
Authors: Niezgoda Michael , Briggs Deborah J. , Shaddock John , Dreesen David W. , Rupprecht Charles E.
Published: January 2024

Objective

To determine susceptibility, incubation and morbidity periods, clinical signs, serologic response, and excretion of virus in domestic ferrets inoculated with rabies virus.

Animals

55 domestic ferrets.

Procedure

5 groups of 10 ferrets were inoculated with rabies virus, IM, at doses of 105.5 to 101.5 median mouse intracerebral lethal dose. Ferrets were observed and behavior was recorded. Rectal temperature, body weight, and samples from the oral cavity and samples of saliva and blood were obtained. Virus isolation was attempted, using intracranial mouse inoculation and cell culture. Virus neutralizing antibodies were determined by rapid fluorescent focus inhibition test. Ferrets were euthanatized immediately if clinical signs were severe. Rabies was confirmed by direct immunofluorescent antibody test.

Results

Mean incubation period was 33 days (range, 16 to 96 days). Clinical signs included ascending paralysis, ataxia, cachexia, bladder atony, fever, hyperactivity, tremors, and paresthesia. Mean morbidity period was 4 to 5 days (range, 2 to 10 days). Virus antigen was detected in brain tissue from all clinically rabid ferrets. Ferrets given the highest viral dose were euthanatized and had VNA; ferrets receiving the next dilution also were euthanatized, but only 4 had seroconverted. Of 17 ferrets that survived, 5 seroconverted. Survivors remained clinically normal except for 1 that recovered with severe paralytic sequelae. Rabies virus was isolated from the salivary gland of 1 ferret that was euthanatized.

Conclusions and Clinical Relevance

Rabies should be considered as a differential diagnosis in any ferret that has acute onset of paralysis or behavioral changes and a condition that rapidly deteriorates despite intense medical intervention. (Am J Vet Res 1997;58:1327–1331)
Functional and phenotypic characterization of monoclonal antibodies to bovine L-selectin
Authors: Wang Yan , Paape Max J. , Leino Lasse , Capuco Anthony V. , Närvä Heini
Published: January 2024

Objective

To characterize 2 bovine neutrophil monoclonal antibodies (MAB) as to effects on bovine neutrophil function and their binding antigens on the cell surface of bovine neutrophils.

Animals

16 healthy, lactating Holstein cattle, 1 calf with leukocyte adhesion deficiency, and 1 age-matched control calf, 2 healthy ewes, and 2 healthy human beings as neutrophil sources.

Procedure

Neutrophil chemotactic and respiratory burst activities and calcium influx, and binding properties of the 2 MAB were determined. Molecular mass of corresponding cell surface antigens also was determined, as was binding of human L-selectin MAB DREG56 to molecules recognized by MAB 11G10 and 2G8 on the surface of bovine neutrophils.

Results

MAB 11G10 and 2G8 inhibited chemotactic activity of bovine neutrophils, up-regulated amplitude of native chemiluminescence, and shortened the time to reach maximal chemiluminescence induced by serum-opsonized zymosan. Crosslinking both MAB with a second antibody induced rapid increase in intracellular free calcium concentration. Binding density of MAB 11G10 and 2G8 to bovine neutrophils treated with trypsin was increased (P < 0.05), compared with that of untreated neutrophils. Neutrophils treated with phosphatidylinositol-specific phospholipase C had decreased (P < 0.05) binding density of MAB 11G10 and 2G8. Binding of the various MAB to neutrophils from calves with bovine leukocyte adhesion deficiency was lower (P < 0.05) than binding to neutrophils from healthy calves. Expression of antigens recognized by the aforementioned MAB on the surface of bovine neutrophils was decreased (P < 0.05) within 10 minutes.

Conclusion

MAB 11G10 and 2G8 recognized L-selectin molecules on bovine neutrophil membrane. L-Selectin (CD62L) is involved in low-affinity adhesion reactions between leukocytes and L-selectin ligand on postcapillary venular endothelial cells. (Am J Vet Res 1997;58:1392–1401)
Quantification of antigen-specific antibody concentrations in tracheal lavage fluid of horses with summer pasture-associated obstructive pulmonary disease
Authors: Seahorn Thomas L. , Beadle Ralph E. , McGorum Bruce C. , Marley Christina L.
Published: January 2024

Objective

To determine whether horses with summer pasture-associated obstructive pulmonary disease (SPAOPD) have increased concentrations of antigen-specific IgG and IgE in tracheal lavage fluid, compared with values in clinically normal horses.

Animals

8 horses (6 females, 2 geldings; 6 Quarter Horses, 2 Appaloosas), 14 to 23 years old and with previous diagnosis of SPAOPD, served as the principal group; 8 horses (2 females, 6 geldings; 1 Quarter Horse, 7 Thoroughbreds), 6 to 9 years old, with no evidence of respiratory tract disease, served as the control group.

Procedure

Data were collected twice during a 1- year period: when all SPAOPD-affected horses were manifesting clinical signs of disease (July), and when all SPAOPD-affected horses appeared clinically normal (February). On each occasion, clinical evaluations were performed and blood and tracheal lavage fluid samples were collected. Transtracheal lavage supernatant was evaluated for mold antigen-specific IgG and IgE concentrations.

Results

Median IgE relative antibody unit (RAU) values were significantly higher in control, compared with principal, horses. The SPAOPD-affected horses had increased concentrations of specific IgG for only 1 antigen, during winter sample collection.

Conclusion

Antigen-specific IgG and IgE RAU values were not increased in SPAOPD-affected horses when these horses were manifesting clinical signs of disease. (Am J Vet Res 1997;58:1408–1411)
Comparative activity in dogs of deltamethrin- and diazinon-impregnated collars against Ctenocephalides felis
Authors: Franc Michel , Cadiergues Marie-Christine
Published: January 2024

Objective

To compare effectiveness of deltamethrin- and diazinon-impregnated collars against fleas (Ctenocephalides felis) in an experimental infestation.

Animals

30 Beagles.

Procedure

Dogs were housed in separate cages. Dogs were infested with 50 fleas each, and fleas were counted 24 hours later. Dogs were then fitted with a collar containing 4% deltamethrin (group 1) or 15% diazinon (group 2). Dogs in group 3 were controls. Fleas were counted 24 and 48 hours after collars were applied, and fleas were then removed. Dogs were reinfested with fleas on days 7, 14, 28, 60, 90, 120, 150, and 210. Fleas were counted 24 and 48 hours after each reinfestation.

Results

48 hours after applying collars, flea counts were not notably decreased. Effectiveness in groups 1 and 2 was 24 and 29%, respectively. Infestation on day 7 was controlled, to a comparable extent, by both insecticides (effectiveness approx 85%). Effectiveness > 97% was obtained after collars had been worn for 14 days. Between days 14 and 91, both collars had comparable effectiveness (> 93%) that did not differ significantly. After day 91, effectiveness of the collar containing diazinon decreased sharply, whereas that of the collar containing deltamethrin remained > 90% until day 152.

Conclusions and Clinical Relevance

The collar containing deltamethrin controlled flea populations on dogs beginning 14 days after application and continuing until day 150. The collar containing diazinon controlled infestation for 90 days. Deltamethrin-impregnated collars are a new formulation that can be introduced into a program to easily control fleas. (Am J Vet Res 1998;59:59–60).
Antimicrobial susceptibility patterns of fungi isolated from horses with ulcerative keratomycosis
Authors: Brooks Dennis E. , Andrew Stacy E. , Dillavou Clayton L. , Ellis Georgeann , Kubilis Paul S.
Published: January 2024

Objectives

To evaluate in vitro susceptibility to topical antifungal medications, as measured by minimum inhibitory concentration (MIC) and 50% inhibitory concentration (IC50%), of fungal isolates from horses with ulcerative keratomycosis in Florida; to compare results with those of other studies to identify differences in susceptibility patterns among fungi isolated from horses in different geographic regions; and to note indications of fungal resistance to drugs tested in other studies.

Sample Population

Corneal fungal cultures from client-owned horses from Florida with ulcerative keratomycosis (n = 22).

Procedure

Fungal cultures were plated on Emmons modified Sabouraud dextrose agar and mycobiotic agar, examined weekly for growth, and kept for a total of 30 days. In vitro MIC and IC50% of fluconazole, itraconazole, ketoconazole, miconazole, and natamycin were measured for each fungal isolate.

Results

Aspergillus (n = 9; 41%), Fusarium (7; 32%), Penicillium (2; 9%), Cylindrocarpon (1; 4%), Scytalidium (1; 4%), and Torulopsis (1; 4%) spp and an unidentified yeast (1; 4%) were isolated. Fungi were most susceptible to antifungal drugs in the following order: natamycin and miconazole equally, itraconazole, and ketoconazole, although no significant difference was found among drugs. Fungi were significantly less susceptible to fluconazole (P < 0.0001) than to the other 4 drugs.

Conclusions

Initial antifungal therapy with topically applied natamycin, miconazole, itraconazole, or ketoconazole is recommended for ulcerative keratomycosis in horses in the subtropical environment of Florida.

Clinical Relevance

Specific antifungal treatment of horses with ulcerative keratomycosis should be based on history, results of ophthalmic examination, cytologic findings, isolation of the pathogenic fungus, and known prevalence of unique ocular fungi in specific geographic areas. In vitro antifungal susceptibility testing may be most beneficial in aiding documentation of pharmacologic susceptibility patterns of fungi in specific geographic regions. (Am J Vet Res 1998; 59:138–142)
Photoreceptor cell death by apoptosis in dogs with sudden acquired retinal degeneration syndrome
Authors: Miller Paul E. , Galbreath Elizabeth J. , Kehren Jeanne C. , Steinberg Howard , Dubielzig Richard R.
Published: January 2024

Objective

To examine the role of apoptosis in retinal photoreceptor degeneration in dogs with sudden acquired retinal degeneration syndrome (SARDS).

Sample Population

Retinas from 3 dogs with SARDS and from 2 clinically normal adult dogs.

Procedure

Apoptosis was identified by in situ endlabeling and observation of characteristic morphologic changes by light microscopy.

Results

The degree of photoreceptor degeneration varied with duration of vision loss in SARDS-affected eyes. The retina of all 3 SARDS-affected eyes had numerous (34, 61, and 70) apoptotic nuclei per section that were overwhelmingly located in the outer nuclear layer. Apoptotic nuclei were not detected, or were rare in similarly sized retinal sections from normal dogs. Inflammation was not an important feature of SARDS.

Conclusions

Apoptosis appears to be at least 1 mechanism of photoreceptor cell death in dogs with SARDS.

Clinical Relevance

Because apoptosis appears to be a final common pathway in many retinal degeneration syndromes, future treatment strategies that control apoptosis in other diseases may be applicable to dogs with SARDS. Halting this pathway may allow some photoreceptors to survive and, perhaps, preserve vision. (Am J Vet Res 1998;59:149–152)
Preclinical evaluation of a sterically stabilized liposome-encapsulated cisplatin in clinically normal cats
Authors: Thamm Douglas H. , Vail David M.
Published: January 2024

Objective

To evaluate the effects of administration of a sterically stabilized liposome-encapsulated cisplatin (SSL-CDDP) to cats.

Animals

4 clinically normal cats.

Procedure

2 of the cats were given multiple IV injections of SSL-CDDP at a dosage of 70 mg of free CDDP equivalent/m2 of body surface area at 3-week intervals. The other 2 cats received single IV injections of identical liposome preparations not containing CDDP. Vital signs; appetite; attitude; hematologic, serum biochemical, and urinalysis findings; and thoracic radiographic views were evaluated at predetermined intervals.

Results

Sterically stabilized liposome-encapsulated cisplatin was well tolerated by all cats. The only significant alterations in measured variables were an increase in serum cholesterol concentration 2 days after injection, and repeatable pyrexia in the cats receiving SSL-CDDP that began 10 to 12 hours after injection and continued for 18 hours, peaking at 40.5 to 41 C. Alterations in rectal temperature were not significant in cats receiving empty liposome vehicle.

Conclusions

SSL-CDDP appears to be safe to administer to cats at a dosage of 70 mg of free CDDP equivalent/m2, a CDDP dose known to be therapeutic in dogs. Pyrexia, although marked, appears to be a short-term and well tolerated side effect.

Clinical Relevance

SSL-CDDP appears to abrogate the uniformly fatal side effects associated with administration of tumoricidal quantities of free CDDP to cats. This new formulation should allow investigation of the antitumor properties of CDDP against spontaneously arising neoplasms in cats. (Am J Vet Res 1998;59:286–289)
Effect of α2-adrenergic, cholinergic, and nonsteroidal anti-inflammatory drugs on myoelectric activity of ileum, cecum, and right ventral colon and on cecal emptying of radiolabeled markers in clinically normal ponies
Authors: Lester Guy D. , Merritt A. M. , Neuwirth Lisa , Vetro-Widenhouse Tamara , Steible Christine , Rice Brett
Published: January 2024

Objective

To determine effect of xylazine hydrochloride (XYL), yohimbine hydrochloride (YOH), bethanechol chloride (BET), neostigmine methyl sulfate (NEO), or flunixin meglumine (FLU) on ileocecocolic myoelectric activity and passage of radiolabeled markers from the cecum.

Animals

6 healthy adult ponies.

Procedure

A cecal cannula was surgically implanted, and 12 were sutured to the ileum, cecum, and right ventral colon. After a 12-hour nonfeeding period, 370 MBq of technetium 99m-labeled sulfur colloid in egg albumen and 37 MBq of indium 111-labeled diethyltriaminepentaacetic acid in 60 ml of water were injected into the cecal apex. All drugs were administered IV as a bolus, with the exception of NEO, which was given SC: XYL, 0.5 mg/kg of body weight; YOH, 0.075 mg/kg; BET, 0.025 mg/kg; NEO, 0.025 mg/kg; FLU, 1.1 mg/kg; and saline solution (SAL), 10 ml. Drugs were administered in a randomized complete block design, each treatment was administered twice to each pony, and dual-phase scintigraphic images were obtained. The time to 50% emptying (t50) and the slope of the emptying curve (β) were derived from the calculated power exponential equation.

Results

The t50 after BET (184.8 ± 16.5 minutes) and NEO (124.7 ± 16.5 minutes) administration were significantly shorter than values after saline (230.2 ± 17.1 minutes) administration. The t50 after XYL administration (250.5 ± 18.6 minutes) was longer, and that after YOH administration (190.1 ± 16.2 minutes) was shorter, than the t50 after saline administration, but neither difference was significant. The t50 and β after FLU administration differed from those after saline administration. Myoelectric data appeared to be well correlated with drug-induced alterations in isotope clearance.

Conclusions and Clinical Relevance

Cholinergic agonists, BET and NEO, have significant effects on the myoelectric activity of ileum, cecum, and right ventral colon, with the net effect of hastening cecal emptying. (Am J Vet Res 1998;59:320–327)
Effect of erythromycin lactobionate on myoelectric activity of ileum, cecum, and right ventral colon, and cecal emptying of radiolabeled markers in clinically normal ponies
Authors: Lester Guy D. , Merritt A. M. , Neuwirth Lisa , Vetro-Widenhouse Tamara , Steible Christine , Rice Brett
Published: January 2024

Objective

To determine the effect of erythromycin lactobionate (ERY) on ileocecocolic myoelectric activity and passage of radiolabeled markers from the cecum.

Animals

6 healthy adult ponies.

Procedure

After a 12-hour nonfeeding period, 370 MBq of technetium 99m-labeled sulfur colloid in egg albumen and 37 MBq of indium 111-labeled diethyltriaminepentaacetic acid in 60 ml of water were administered directly into the cecal apex. The following drug concentrations were tested: ERY, 0.01, 0.10, 1.0, and 10.0 mg/kg of body weight; ERY, 0.10 mg/kg bolus; and saline (0.9% NaCl) solution, 10 ml. All treatments, with the exception of the 0.10-mg/kg bolus and saline solution, were infusions administered IV during a 60-minute period in a randomized complete block design. Each treatment was administered 2 times/pony. Dual-phase scintigraphic images were obtained, and the best-fit function was determined for each study, using data from the right side. Myoelectric data were collected before and after each treatment and analyzed for spike burst rate, relative activity, and burst duration.

Results

The time to 50% emptying (t50) after ERY administration was dose dependent, and all treatments, with the exception of the 0.01-mg/kg infusion, resulted in a significantly shorter t50 than that observed after saline administration (230.2 ± 17.12 minutes). The shortest t50 was observed after the 1.0 mg/kg dosage of ERY (76.9 ± 22.0 minutes). Although not significantly different, the t50 and β were shorter (108.6 ± 25.9 minutes) and steeper after a bolus dose of 0.10 mg/kg of ERY than after infusion at the same dosage (131.1 ± 18.7 minutes).

Conclusions and Clinical Relevance

ERY may be a useful prokinetic for prevention or treatment of cecal motility dysfunction. The ability of ERY to evoke a similar response during the early postanesthetic or postoperative period remains to be determined. (Am J Vet Res 1998;59:328–334)
Evaluation of the morphologic characteristics and prevalence of canine urocystoliths from a regional urolith center
Authors: Weichselbaum Ralph C. , Feeney Daniel A. , Jessen Carl R. , Osborne Carl A. , Koehler Lori , Ulrich Lisa
Published: January 2024

Objective

To determine whether morphology of single-mineral urocystoliths and age, sex, or breed data could be applied to facilitate radiographic and clinical urocystolith mineral type prediction, respectively, in dogs.

Sample Population

Database of 2,041 dogs with pure mineral composition urocystoliths.

Procedure

All uroliths were characterized according to geologic descriptive terminology and by breed, sex, and age of dog at time of sample submission. Summary statistics were used to compare features with specific mineral types. Observed trends were analyzed for statistical relevance between observed and expected frequencies for age, sex, color, size, shape, and surface, using the null hypothesis that differences by urocystolith mineral type did not exist. On the basis of expected breed occurrence derived by equations, the null hypothesis that urocystolith occurrence paralleled canine breed popularity was tested.

Results

Urocystoliths > 10 mm in any dimension were > 92% likely to be magnesium ammonium phosphate hexahydrate (MAP). Smooth, blunt-edged or faceted, and pyramidal urocystoliths were usually MAP. Jackstone shapes were almost always silica. Botryoidal (grape-like clusters) urocystoliths were likely to be oxalates. Breeds with high relative likelihood of urocystoliths included: English Bulldog, Pekingese, Pug, Welsh Corgi, and West Highland White Terrier. Breeds with low relative likelihood of urocystolith production included: German Shepherd Dog, Shar-Pei, and German Shorthaired Pointer. About 94% of urocystoliths produced in females or spayed females were MAP, whereas males and neutered males produced a greater assortment.

Conclusions and Clinical Relevance

For pure mineral composition urocystoliths, trends in mineral type among breeds and between sexes can be exploited clinically in the diagnosis and management of urolith-related disease. Size and shape, used in conjunction with age, breed, and sex, can facilitate pure urocystolith mineral type prediction. (Am J Vet Res 1998;59:379–387)
Inhibition of pilocarpine-induced aqueous humor flare, hypotony, and miosis by topical administration of anti-inflammatory and anesthetic drugs to dogs
Authors: Krohne Sheryl Greve , Gionfriddo Juliet , Morrison Elizabeth A.
Published: January 2024

Objective

To investigate the mechanism by which pilocarpine causes increased aqueous humor (AH) flare, hypotony, and miosis in dogs.

Animals

6 dogs with normal eyes.

Procedure

Both eyes of each dog were treated topically with a 2% solution of pilocarpine, and 1 eye of each dog was additionally treated with commercially available ophthamic solutions. Breakdown of the blood-aqueous barrier (BAB) was quantitated in each eye, using laser flaremetry to measure AH flare. Intraocular pressure and pupil size were also measured.

Results

Pilocarpine caused increased flare from BAB breakdown that was inhibited by the drugs tested. Inhibition (most to least) of BAB breakdown was flurbiprofen more than diclofenac, proparacaine, or suprofen, which were more than 0.125 or 1.0% prednisolone. Inhibition appeared dose-dependent and caused consensual inhibition in the contralateral eye. Intraocular pressure was decreased only in proparacaine-treated eyes and increased in eyes treated with nonsteroidal anti-inflammatory drugs (NSAID). Flurbiprofen and proparacaine were the most effective at blocking miosis.

Conclusions

Pilocarpine produced a predictable, reproducible BAB breakdown in dogs. Miosis and increased AH flare were inhibited equally by proparacaine or NSAID, suggesting that these signs were caused by neuropeptide release into the AH from antidromic stimulation, which subsequently triggers prostaglandin production. Hypotony was inhibited only by anti-inflammatory drugs.

Clinical Relevance

Proparacaine in combination with pilocarpine would be the best choice for treating dogs with acute glaucoma. Topical administration of NSAID should not be used to treat dogs with acute glaucoma, because they increase intraocular pressure and negate the effects of pilocarpine. (Am J Vet Res 1998;59:482–488)
Vascular and transsynovial forces of the isolated stationary equine joint
Authors: Bertone Alicia L. , Hardy Joanne , Simmons Emily J. , Muir William W.
Published: January 2024

Objective

To provide quantitative assessment of forces affecting filtration of synovial fluid in response to incremental changes in arterial and venous hemodynamics.

Animals

7 clinically normal adult horses.

Procedure

Using a stationary, isolated metacarpophalangeal joint preparation, blood flow (Qacir), tissue perfusion, arterial pressure (Pacir), venous pressure (Pvcir), transsynovial fluid flow, total vascular resistance, vascular compliance, and tissue compliance were evaluated before and after arterial and venous pressure manipulations. At isogravimetric conditions, pre- and postcapillary resistance and ratios, osmotic reflection coefficient (σd), capillary pressure, net filtration pressure, and transitional microvascular pressure were determined.

Results

Synovial tissue blood flow was similar before, immediately after, and 3.5 hours after joint isolation. The σd for the joint was low, owing to the high oncotic pressure of synovial fluid at filtration-independent states. Transsynovial flow occurred in preference to lymph flow because of the high permeability of synovial tissue (low σd). Synovial fluid production and transfluid flow (synovium weight gain) increased at Pacir > 200 mm of Hg, indicating a threshold phenomenon for synovial filtration. Net filtration pressure > 6 mm of Hg is needed to effect an increase in synovial fluid flow, and pressure of approximately 11 mm of Hg is necessary to increase lymphatic flow. Vascular compliance in the joint was low, but increased markedly with Pvcir. Vascular and tissue compliance increased with increased Pacir. Vascular compliance changes caused by increased arterial pressure were minimal, compared with those caused by increased venous pressure owing to the greater elastance of arteries and the larger muscular arterial wall.

Conclusion

This isolated joint preparation permitted evaluation of codependent hemodynamic, microvascular, and transsynovial flow responses to hemodynamic manipulations. Synovial tissue permeability was markedly affected by increased vascular forces altering filtration pressures toward synovial fluid production. (Am J Vet Res 1998;59:495–503)