Objective-To assess effects of body position on direct measurements of intra-abdominal pressure (IAP) and abdominal perfusion pressure (APP) in horses anesthetized with total intravenous anesthesia (TIVA). Animals-9 healthy adult horses. Procedures-Instrumentation in unsedated standing horses involved insertion of an arterial catheter for blood pressure measurements and 3 intraperitoneal cannulas (left flank, right flank, and ventral abdomen) for IAP measurements. Baseline values were measured for heart rate, respiratory rate, systolic arterial blood pressure, mean arterial blood pressure (MAP), diastolic arterial blood pressure, and IAP. Horses were medicated with xylazine, and pressures were measured again. Anesthesia was induced with ketamine-diazepam and maintained with a ketamine-guaifenesin infusion. Horses were positioned twice into left lateral recumbency, right lateral recumbency, or dorsal recumbency. Hemodynamic pressures and accessible abdominal pressures were measured for each recumbency position. The APP was calculated as MAP - IAP. Differences in IAP, MAP, APP and sedation (standing horses) or body position (anesthetized horses) were compared by means of repeated-measures ANOVA or paired t tests. Results-Baseline hemodynamic and IAPs were not different after xylazine administration. Ventral abdomen IAP and MAP were lower for horses in dorsal recumbency than in right or left lateral recumbency. Ventral abdomen APP remained unchanged. For lateral recumbencies, flank IAP was lower and APP was higher than pressure measurements at the same sites during dorsal recumbency. Conclusions and Clinical Relevance-Body position affected IAP and APP in healthy anesthetized horses. These effects should be considered when developing IAP acquisition methods for use in horses with abdominal disease.

The unfolded protein response (UPR), a conserved cellular response to stressors such as hypoxia and nutrient deprivation, is associated with angiogenesis and metastasis in tumor cells. This article discusses a pilot study conducted to determine whether components of the UPR could be identified in spontaneous canine tumors and whether they were up-regulated within tumor tissue compared with adjacent normal tissue. Tissue samples of various spontaneous canine neoplasms were taken from 13 dogs shortly after surgical excision or euthanasia; control samples were taken from adjacent normal tissue. RNA purification and real-time quantitative reverse-transcription polymerase chain reaction were done to measure the expression of 4 genes associated with the UPR (HERP, CHOP, GRP78, and XBP1s). The results indicated that UPR gene expression can be identified in spontaneous canine tumors and that the UPR is up-regulated, as indicated by significantly increased expression of CHOP and GRP78 within the tumor.

The purpose of the study was to compare the conductance and mannitol permeability of canine colonic mucosa in response to carprofen or 2,4-dinitrophenol (DNP) with or without tempol pretreatment. Ten colonic mucosa sections per dog were mounted in Ussing chambers. Treatments were done in duplicate. Mucosa was exposed to carprofen (200 μg/mL) or DNP (0.25 mM), both with and without tempol (1 mM) pretreatment. Conductance was calculated every 15 min for 240 min. Mannitol flux was calculated over 3 consecutive 60-minute periods. Histology or electron microscopy was done after exposure. Conductance over time, mannitol flux, frequency of histologic categories, and electron microscopic changes were analyzed for treatment effects. The mean ± standard deviation (SD) conductance over time for carprofen or DNP-treated colons was not significantly different from control regardless of tempol pretreatment. Period 3 mannitol fluxes for carprofen and DNP-treated colon were not significantly different, but were greater than control. Period 3 mannitol flux for tempol + carprofen was significantly less than tempol + DNP-treated colon. Sloughing of cells and erosions were seen in the mucosa of carprofen-treated colon. Mitochondrial damage was seen more often in carprofen-treated than DNP-treated or control colon. Tempol pretreatment resulted in more ruptured mitochondria in the carprofen-treated colon; however, other mitochondrial changes were not significantly affected by tempol pretreatment in either carprofen or DNP treated colon. Treatment with carprofen or DNP increased the mannitol flux, but pretreatment with tempol mitigated the carprofen effect. It is apparent that structural mitochondrial damage occurs in the canine colonic mucosa after carprofen and DNP exposure.

Objective-To evaluate the thermal antinociceptive and sedative effects and duration of action of tramadol hydrochloride after oral administration to American kestrels (Falco sparverius). Animals-12 healthy 3-year-old American kestrels. Procedures-Tramadol (5, 15, and 30 mg/kg) and a control suspension were administered orally in a masked randomized crossover experimental design. Foot withdrawal response to a thermal stimulus was determined 1 hour before (baseline) and 0.5, 1.5, 3, 6, and 9 hours after treatment. Agitation-sedation scores were determined 3 to 5 minutes before each thermal stimulus test. Results-The lowest dose of tramadol evaluated (5 mg/kg) significantly increased the thermal foot withdrawal thresholds for up to 1.5 hours after administration, compared with control treatment values, and for up to 9 hours after administration, compared with baseline values. Tramadol at doses of 15 and 30 mg/kg significantly increased thermal thresholds at 0.5 hours after administration, compared with control treatment values, and up to 3 hours after administration, compared with baseline values. No significant differences in agitation-sedation scores were detected between tramadol and control treatments. Conclusions and Clinical Relevance-Results indicated oral administration of 5 mg of tramadol/kg significantly increased thermal nociception thresholds for kestrels for 1.5 hours, compared with a control treatment, and 9 hours, compared with baseline values; higher doses resulted in less pronounced antinociceptive effects. Additional studies with other types of stimulation, formulations, dosages, routes of administration, and testing times would be needed to fully evaluate the analgesic and adverse effects of tramadol in kestrels and other avian species.

Objective- To evaluate the feasibility and repeatability of in vivo measurement of stiffness gradients by means of acoustoelastography in the superficial digital flexor tendons (SDFTs) of clinically normal horses. Animals- 15 clinically normal horses. Procedures- For each horse, stiffness gradient index and dispersion values for SDFTs in both forelimbs were evaluated in longitudinal orientation by use of acoustoelastography at 3 sites (5, 10, and 15 cm distal to the accessory carpal bone) by 2 observers; for each observer, data were acquired twice per site. The left forelimb was always scanned before the right forelimb. Lifting of the contralateral forelimb with the carpus flexed during image acquisition resulted in the required SDFT deformation in the evaluated limb. Interobserver repeatability, intraobserver repeatability, and right-to-left limb symmetry for stiffness gradient index and dispersion values were evaluated. Results- Stiffness gradient index and dispersion values for SDFTs at different locations as well as effects of age or sex did not differ significantly among the 15 horses. Interclass correlation coefficients for interobserver repeatability, intraobserver repeatability, and limb symmetry revealed good to excellent agreement (intraclass correlation coefficients, > 0.74). Conclusions and Clinical Relevance- Results indicated that acoustoelastography is a feasible and repeatable technique for measuring stiffness gradients in SDFTs in clinically normal horses, and could potentially be used to compare healthy and diseased tendon states.

Objective- To assess kinetic 2-([(18)F]fluoro)-2-deoxy-d-glucose ((18)FDG) uptake in the brain of anesthetized healthy adult dogs by use of positron emission tomography (PET) and to determine whether (18)FDG uptake differs among anatomic regions of the brain. Animals- 5 healthy Beagles. Procedures- Each isoflurane-anesthetized dog was administered (18)FDG IV (dose range, 3.0 to 5.2 mCi), and PET data were acquired for 2 hours. A CT scan (without contrast agent administration) was performed to allow more precise neuroanatomic localization. Defined regions of interest within the brain were drawn on reconstructed image data. Standard uptake values (SUVs) for (18)FDG were calculated to generate time-activity curves and determine time to peak uptake. Results- Time-activity curve analysis identified 4 regional uptake patterns: olfactory, gray matter, white matter, and other (brainstem, cerebellum, and occipital and frontal regions). The highest maximum SUVs were identified in the olfactory bulbs and cerebral gray matter, and the lowest maximum SUV was identified in cerebral white matter. Mean time to peak uptake ranged from 37.8 minutes in white matter to 82.7 minutes in the olfactory bulbs. Conclusions and Clinical Relevance- Kinetic analysis of (18)FDG uptake revealed differences in uptake values among anatomic areas of the brain in dogs. These data provide a baseline for further investigation of (18)FDG uptake in dogs with immune-mediated inflammatory brain disease and suggest that (18)FDG-PET scanning has potential use for antemortem diagnosis without histologic analysis and for monitoring response to treatment. In clinical cases, a 1-hour period of PET scanning should provide sufficient pertinent data.

Objective-To determine the pharmacokinetics of ceftiofur crystalline-free acid (CCFA) following SC administration of a single dose to sheep. Animals-9 healthy adult female Suffolk-crossbred sheep. Procedures-Each sheep was administered 6.6 mg of CCFA/kg, SC, in the cervical region once. Serial blood samples were collected at predetermined intervals for 14 days. Serum concentration of ceftiofur free-acid equivalents (CFAE) was determined by high-performance liquid chromatography. Pharmacokinetic parameters were determined by compartmental and noncompartmental methods. Results-Pharmacokinetics for CCFA following SC administration in sheep was best described with a 1-compartment model. Mean +/- SD area under the concentration-time curve from time 0 to infinity, peak serum concentration, and time to peak serum concentration were 206.6 +/- 24.8 μ•h/mL, 2.4 +/- 0.5 μg/mL, and 23.1 +/- 10.1 h, respectively. Serum CFAE concentrations ≥ 1 μg/mL (the target serum CFAE concentration for treatment of disease caused by Mannheimia haemolytica and Pasteurella multocida) were maintained for 2.6 to 4.9 days. No significant adverse reactions to CCFA administration were observed. Conclusions and Clinical Relevance-Results indicated that adequate therapeutic serum concentrations of CFAE for treatment of disease caused by M haemolytica and P multocida were achieved in sheep following SC administration of a single dose (6.6 mg/kg) of CCFA. Thus, CCFA might be useful for the treatment of common respiratory tract pathogens in sheep.

Objective-To evaluate the cardiorespiratory effects of IV administration of propofol (4 mg/kg), ketamine hydrochloride and propofol (2 mg/kg each; K-P), or ketamine hydrochloride (5 mg/kg) and diazepam (0.2 mg/kg; K-D) before and after induction of anesthesia (IoA) in dogs sedated with acepromazine maleate and oxymorphone hydrochloride. Animals-10 healthy adult Beagles. Procedures-Each dog was randomly allocated to receive 2 of 3 treatments (1-week interval). For instrumentation prior to each treatment, each dog was anesthetized with isoflurane. After full recovery, acepromazine (0.02 mg/kg) and oxymorphone (0.05 mg/kg) were administered IV. Fifteen minutes later (before IoA), each dog received treatment IV with propofol, K-P, or K-D. Cardiorespiratory and arterial blood gas variables were assessed before, immediately after, and 5 minutes after IoA. Results-Compared with findings before IoA, dogs receiving the K-P or K-D treatment had increased cardiac output, oxygen delivery, and heart rate 5 minutes after IoA; K-P administration did not change mean arterial blood pressure or stroke volume and decreased systemic vascular resistance. Propofol decreased mean arterial blood pressure and systemic vascular resistance immediately after IoA but did not change heart rate, cardiac output, or oxygen delivery. All treatments caused some degree of apnea, hypoventilation, and hypoxemia (Pao2 < 80 mm Hg). Conclusions and Clinical Relevance-In dogs, K-P treatment maintained mean arterial blood pressure better than propofol alone and increased heart rate, cardiac output, or oxygen delivery, as did the K-D treatment. Supplemental 100% oxygen should be provided during IoA with all 3 treatments.

Objective—To describe the contrast-enhanced ultrasonographic characteristics and vascular patterns of adrenal gland tumors in dogs and determine whether those features are indicative of malignancy or histologic type of tumor. Animals—14 dogs with 16 adrenal gland lesions (10 carcinomas [8 dogs], 3 adenomas [3 dogs], and 3 pheochromocytomas [3 dogs]). Procedures—Unsedated dogs with adrenal gland lesions underwent B-mode ultrasonography and contrast-enhanced ultrasonography ≤ 48 hours before adrenalectomy; contrast-enhanced ultrasonographic examinations were video-recorded. Macroscopic evaluation of the adrenal gland lesions and histologic examination of removed adrenal gland tissues were subsequently performed. Surgical and histopathologic findings and the ultrasonographic and contrast-enhanced ultrasonographic characteristics were recorded for the various tumor types. Time-intensity curves were generated from the contrast-enhanced ultrasonographic recordings and used to calculate regional blood volume (value proportional to area under the curve) and mean transit time (time the lesion began to enhance to the half-peak intensity). Results—In adrenal gland carcinomas, tortuous feeding vessels were noticeable during the arterial and venous phases of contrast enhancement. Heterogeneity of contrast enhancement was evident only in malignant tumors. Compared with adenomas, adrenal gland carcinomas and pheochromocytomas had significantly less regional blood volume. Mean transit times were significantly shorter in adrenal gland carcinomas and pheochromocytomas than in adenomas. Conclusions and Clinical Relevance—For dogs, evaluation of the vascular pattern and contrast-enhancement characteristics of adrenal gland tumors by means of contrast-enhanced ultrasonography may be useful in assessment of malignancy and tumor type.

No controlled studies have been conducted to determine the predilection muscles of Trichinella zimbabwensis larvae in Nile crocodiles (Crocodylus niloticus) or the influence of infection intensity on the distribution of the larvae in crocodiles. The distribution of larvae in muscles of naturally infected Nile crocodiles and experimentally infected caimans (Caiman crocodilus) and varans (Varanus exanthematicus) have been reported in literature. To determine the distribution patterns of T. zimbabwensis larvae and predilection muscles, 15 crocodiles were randomly divided into three cohorts of five animals each, representing high infection (642 larvae/kg of bodyweight average), medium infection (414 larvae/kg of bodyweight average) and low infection (134 larvae/kg of bodyweight average) cohorts. In the high infection cohort, high percentages of larvae were observed in the triceps muscles (26%) and hind limb muscles (13%). In the medium infection cohort, high percentages of larvae were found in the triceps muscles (50%), sternomastoid (18%) and hind limb muscles (13%). In the low infection cohort, larvae were mainly found in the intercostal muscles (36%), longissimus complex (27%), forelimb muscles (20%) and hind limb muscles (10%). Predilection muscles in the high and medium infection cohorts were similar to those reported in naturally infected crocodiles despite changes in infection intensity. The high infection cohort had significantly higher numbers of larvae in the sternomastoid, triceps, intercostal, longissimus complex, external tibial flexor, longissimus caudalis and caudal femoral muscles (p < 0.05) compared with the medium infection cohort. In comparison with the low infection cohort, the high infection cohort harboured significantly higher numbers of larvae in all muscles (p < 0.05) except for the tongue. The high infection cohort harboured significantly higher numbers of larvae (p < 0.05) in the sternomastoid, triceps, intercostal, longissimus complex, external tibial flexor, longissimus caudalis and caudal femoral muscles compared with naturally infected crocodiles. Results from this study show that, in Nile crocodiles, larvae of T. zimbabwensis appear first to invade predilection muscles closest to their release site in the small intestine before occupying those muscles situated further away. The recommendation for the use of masseter, pterygoid and intercostal muscles as sampling sites for the detection of T. zimbabwensis in crocodiles is in contrast to the results from this study, where the fore- and hind limb muscles had the highest number of larvae. This study also supports the use of biopsy sampling from the dorso-lateral regions of the tail for surveillance purposes in both wild and commercial crocodile populations.