OBJECTIVE To determine the impact of mechanical ventilation (MV) and perfusion conditions on the efficacy of pulse-delivered inhaled nitric oxide (PiNO) in anesthetized horses. ANIMALS 27 healthy adult horses. PROCEDURES Anesthetized horses were allocated into 4 groups: spontaneous breathing (SB) with low (< 70 mm Hg) mean arterial blood pressure (MAP; group SB-L; n = 7), SB with physiologically normal (≥ 70 mm Hg) MAP (group SB-N; 8), MV with low MAP (group MV-L; 6), and MV with physiologically normal MAP (group MV-N; 6). Dobutamine was used to maintain MAP > 70 mm Hg. Data were collected after a 60-minute equilibration period and at 15 and 30 minutes during PiNO administration. Variables included Pao2, arterial oxygen saturation and content, oxygen delivery, and physiologic dead space-to-tidal volume ratio. Data were analyzed with Shapiro-Wilk, Mann-Whitney U, and Friedman ANOVA tests. RESULTS Pao2, arterial oxygen saturation, arterial oxygen content, and oxygen delivery increased significantly with PiNO in the SB-L, SB-N, and MV-N groups; were significantly lower in group MV-L than in group MV-N; and were lower in MV-N than in both SB groups during PiNO. Physiologic dead space-to-tidal volume ratio was highest in the MV-L group. CONCLUSIONS AND CLINICAL RELEVANCE Pulmonary perfusion impacted PiNO efficacy during MV but not during SB. Use of PiNO failed to increase oxygenation in the MV-L group, likely because of profound ventilation-perfusion mismatching. During SB, PiNO improved oxygenation irrespective of the magnitude of blood flow, but hypoventilation and hypercarbia persisted. Use of PiNO was most effective in horses with adequate perfusion.

OBJECTIVE To develop a reliable method for injection of the tarsometatarsal (TMT) joint of horses through a medial approach and to characterize anatomy of the synovial recesses of the TMT joint with CT. SAMPLE 13 pairs of fresh cadaveric equine tarsi. PROCEDURES TMT joints were assessed with radiography and CT. Twelve pairs of TMT joints were assigned to an experienced veterinarian (8 joints) or veterinary student (16 joints) for injection with contrast medium through a medial or a lateral approach. Every TMT joint was then reexamined radiographically and with CT to assess diffusion of contrast medium. The number of attempts for the lateral and medial approaches between and within investigators was evaluated, which included evaluation of the diffusion of contrast solution in relation to the approach used. RESULTS All 24 TMT joints were successfully injected, as confirmed with radiography and CT. There was no significant difference in the number of attempts between the medial and lateral approaches and between investigators. No significant difference was detected in the distribution of contrast medium in each synovial recess between the medial and lateral approaches. CONCLUSIONS AND CLINICAL RELEVANCE The medial approach described here for injection of the TMT joint of horses was highly reliable. It involved use of an easily palpable anatomic landmark on the mediodistal aspect of the TMT joint. An established alternative method for injection of the TMT joint may be useful in clinical practice for diagnostic and therapeutic purposes, although a medial approach may increase risk of injury to veterinarians.

The efficacy of a porcine reproductive and respiratory syndrome (PRRS) subunit vaccine was evaluated and compared with a modified-live virus (MLV) vaccine under field conditions. Three farms were selected based on their history of respiratory diseases caused by co-infection with both PRRSV-1 and PRRSV-2. In each farm, 60 pigs were randomly allocated to 2 vaccinated and 1 unvaccinated groups (20 pigs per group). One group of pigs were administered the PRRS subunit vaccine at 21 and 42 days of age and another group administered the PRRS MLV vaccine at 21 days of age. The subunit vaccine had similar efficacy and, in some instances, performed even better than the MLV vaccine. Vaccination of pigs with either of the PRRS vaccines resulted in significantly improved growth performance in Farm B but not in Farm C. In Farm A, pigs vaccinated with the PRRS subunit vaccine had a better growth performance statistically compared to those vaccinated with the PRRS MLV vaccine. At the peak of PRRSV-1 and PRRSV-2 viremia, neutralizing antibodies and T-cell responses against PRRSV-1 and PRRSV-2 were at low levels suggesting that either vaccine is only able to provide a partial protection against co-circulating PRRSV-1 and PRRSV-2.

OBJECTIVE To evaluate and report measurements of the radiographic cardiac silhouette of healthy juvenile and adult ospreys (Pandion haliaetus). ANIMALS 54 ospreys (22 adults, 19 juveniles, and 13 birds of undetermined age) without clinical signs of cardiac disease and with adequate ventrodorsal radiographic images for cardiac silhouette assessment. PROCEDURES Radiographs of ospreys were assessed to determine cardiac width at the widest point as well as sternal width and thoracic width at the same level. Two-way mixed-effects models were used to evaluate interrater reliability for mean rating. Multivariable linear regression analysis was used to create predictive models of cardiac width and to establish a theoretical reference range for healthy ospreys. RESULTS Cardiac width of healthy ospreys was approximately 90% to 92% of sternal width and 67% to 69% of thoracic width. Both sternal width and thoracic width were significant predictors of cardiac width in independent predictive models as well as in a combined model after controlling for age. Thirty-four of 41 (83%) measured cardiac widths were within the theoretical reference range. CONCLUSIONS AND CLINICAL RELEVANCE Ospreys are sentinels used in monitoring environmental health. Environmental factors may have an impact on the cardiac health of ospreys, but reference values for healthy ospreys have not been established for use in assessing cardiomegaly in this species. The radiographic ratios and predictive model obtained in this study may be useful for objective evaluation of cardiomegaly in ospreys.

OBJECTIVE To determine whether passage of whole blood through a microaggregate filter by use of a syringe pump would damage canine erythrocytes. SAMPLE Blood samples obtained from 8 healthy client-owned dogs. PROCEDURES Whole blood was passed through a standard microaggregate filter by use of a syringe pump at 3 standard administration rates (12.5, 25, and 50 mL/h). Prefilter and postfilter blood samples were collected at the beginning and end of a simulated transfusion. Variables measured at each time point included erythrocyte osmotic fragility, mean corpuscular fragility, RBC count, hemoglobin concentration, RBC distribution width, and RBC morphology. In-line pressure when blood passed through the microaggregate filter was measured continuously throughout the simulated transfusion. After the simulated transfusion was completed, filters were visually analyzed by use of scanning electron microscopy. RESULTS Regardless of administration rate, there was no significant difference in mean corpuscular fragility, RBC count, hemoglobin concentration, or RBC distribution width between prefilter and postfilter samples. Additionally, there were no differences in in-line pressure during the simulated transfusion among administration rates. Echinocytes were the erythrocyte morphological abnormality most commonly observed at the end of the transfusion at administration rates of 12.5 and 25 mL/h. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that regardless of the administration rate, the microaggregate filter did not alter fragility of canine RBCs, but may have altered the morphology. It appeared that the microaggregate filter would not contribute to substantial RBC damage for transfusions performed with a syringe pump.

OBJECTIVE To determine effects of hydrocortisone administration on serum leptin and adiponectin concentrations, abdominal fat distribution, and mRNA expression of leptin and adiponectin in abdominal adipose tissue of dogs. ANIMALS 12 healthy dogs. PROCEDURES Dogs received hydrocortisone (8.5 mg/kg; n = 6) or a placebo (6) orally every 12 hours for 90 days. Serum leptin and adiponectin concentrations were measured with a canine-specific ELISA on the day before (day 0; baseline) and during (days 1, 3, 7, 30, 60, and 90) administration. On days 0, 30, 60, and 90, abdominal fat mass was quantified with CT, and mRNA expression of leptin and adiponectin in abdominal fat was analyzed by use of a PCR assay. RESULTS Hydrocortisone administration resulted in an increase in visceral fat mass on days 60 and 90, compared with the mass at baseline. Visceral fat mass at the level of L3 increased during hydrocortisone administration. Serum leptin concentration began to increase on day 1 and was significantly higher than the baseline concentration on days 30 and 60. Serum adiponectin concentration on days 30, 60, and 90 was significantly lower than the baseline concentration. Leptin and adiponectin mRNA expression in abdominal fat was greater on day 30, compared with expression at baseline, but lower on days 60 and 90, compared with expression on day 30. Serum leptin concentration and visceral fat mass were correlated. CONCLUSIONS AND CLINICAL RELEVANCE Hydrocortisone administration affected abdominal fat distribution and serum leptin and adiponectin concentrations through dysregulation of leptin and adiponectin expression.

Analysis of hematologic and biochemical values in pigs is an important basis for biomedical research and veterinary clinical diagnosis. Reference values for specific-pathogen-free (SPF) 1-month-old Yorkshire (Y) pigs and Yorkshire-Landrace crossbred (YL) pigs are limited. The present research aimed to describe and compare the reference values for hematologic and biochemical parameters in such pigs. Blood samples were obtained from 90 Y pigs (52 males and 38 females) and 88 YL pigs (55 males and 33 females), all 1 month old and bred in an SPF environment. Among the 16 hematologic and 15 serum biochemical parameters tested, no significant differences between the Y and YL pigs were found except in the concentration of triglyceride (P < 0.05), and heterosis was not observed. Thus, the values determined in this study can be used as basic reference values for 1-month-old Y and YL pigs and will contribute to the use of SPF pigs in biomedical research.

OBJECTIVE To compare results of a commercially available device for oscillometrically measured blood pressure (OBP) with invasively measured blood pressure (IBP) in awake and anesthetized dogs. ANIMALS 19 adult dogs (mean ± SD body weight, 17.8 ± 7.5 kg). PROCEDURES Blood pressures were measured in dogs while they were awake and anesthetized with isoflurane. The OBP was recorded on a thoracic limb, and IBP was simultaneously recorded from the median caudal artery. Agreement between OBP and IBP was evaluated with the Bland-Altman method. Guidelines of the American College of Veterinary Internal Medicine (ACVIM) were used for validation of the oscillometric device. RESULTS In awake dogs, mean bias of the oscillometric device was −11.12 mm Hg (95% limits of agreement [LOA], −61.14 to 38.90 mm Hg) for systolic arterial blood pressure (SAP), 9.39 mm Hg (LOA, −28.26 to 47.04 mm Hg) for diastolic arterial blood pressure (DAP), and −0.85 mm Hg (LOA, −40.54 to 38.84 mm Hg) for mean arterial blood pressure (MAP). In anesthetized dogs, mean bias was −12.27 mm Hg (LOA, −47.36 to 22.82 mm Hg) for SAP, −3.92 mm Hg (LOA, −25.28 to 17.44 mm Hg) for DAP, and −7.89 mm Hg (LOA, −32.31 to 16.53 mm Hg) for MAP. The oscillometric device did not fulfill ACVIM guidelines for the validation of such devices. CONCLUSIONS AND CLINICAL RELEVANCE Agreement between OBP and IBP results for awake and anesthetized dogs was poor. The oscillometric blood pressure device did not fulfill ACVIM guidelines for validation. Therefore, clinical use of this device cannot be recommended.

OBJECTIVE To evaluate efficacy and safety of anesthesia with dexmedetomidine-ketamine-midazolam (DKM) in five-striped palm squirrels (Funambulus pennantii). ANIMALS 8 male squirrels. PROCEDURES Squirrels were anesthetized with DKM (dexmedetomidine, 0.1 mg/kg; ketamine hydrochloride, 30 mg/kg; and midazolam, 0.75 mg/kg) administered IM. Atipamezole (0.15 mg/kg) and flumazenil (0.1 mg/kg) were administered IM 40 minutes after induction of anesthesia. Vital signs and responses were recorded every 5 minutes during anesthesia. RESULTS Anesthetic induction and recovery from anesthesia were rapid and without complications in all squirrels. Median anesthetic induction time was 67.5 seconds (interquartile [25th to 75th percentile] range, 5.5 seconds), and mean ± SD recovery time after drug reversal was 147 ± 79 seconds. Heart rate, respiratory rate, and rectal temperature significantly decreased during the anesthetic period. All squirrels became hypothermic by 40 minutes after induction. The righting reflex was absent during the 40-minute anesthetic period in all squirrels, with variable responses for the palpebral reflex, jaw tone, forelimb withdrawal reflex, and hind limb withdrawal reflex. Only 2 of 8 squirrels had loss of the limb withdrawal reflex in both the forelimbs and hind limbs from anesthetic induction to 25 minutes after induction. CONCLUSIONS AND CLINICAL RELEVANCE DKM appeared to provide safe and effective anesthesia in five-striped palm squirrels, but oxygen and thermal support were indicated. At the doses administered, deep surgical anesthesia was not consistently achieved, and anesthetic depth of individual squirrels must be determined before surgical procedures are performed in palm squirrels anesthetized with this drug combination.

OBJECTIVE To investigate luteinizing hormone (LH) receptor expression in canine nonneoplastic and neoplastic lymph nodes, circulating nonneoplastic lymphocytes, and T-cell lymphoma (TCL) cell lines. SAMPLE Formalin-fixed, paraffin-embedded lymph nodes (5 neoplastic and 3 nonneoplastic) from 6 dogs, circulating lymphocytes from venous blood specimens obtained from 12 healthy dogs, and 3 TCL cell lines derived from 3 dogs with primary lymphoma. PROCEDURES Lymph node specimens were immunohistochemically stained for determination of LH receptor expression. Circulating nonneoplastic lymphocytes and TCL cell lines were evaluated for LH receptor expression by use of flow cytometry; circulating lymphocytes were also immunophenotyped. The mean percentage of cells positive for LH receptors was determined for each type of specimen. For the healthy dogs, percentages of circulating B and T lymphocytes that expressed LH receptors were assessed on the basis of sex and reproductive status. RESULTS The mean percentage of LH receptor-positive cells in canine neoplastic and nonneoplastic lymph nodes was 12.4% and 4.1%, respectively. For the healthy dogs, the mean percentage of circulating LH receptor-positive T lymphocytes was significantly higher in gonadectomized dogs (16.6%) than in sexually intact dogs (10.5%); the percentages of circulating LH receptor-positive B lymphocytes did not significantly differ by reproductive status. Among the 3 canine TCL cell lines, LH receptor expression ranged from 10% to 45%. CONCLUSIONS AND CLINICAL RELEVANCE In this study, LH receptor expression by canine neoplastic and nonneoplastic lymphocytes was detected. Research into the effects of downregulation of LH receptor activation in dogs with lymphoma is warranted.