Objective—To determine dose dependency of tranexamic acid–induced emesis and the time course of the antifibrinolytic potency of tranexamic acid in dogs. Animals—10 Beagles. Procedures—In a dose-escalating experiment, ascending doses of tranexamic acid (10, 20, and 30 mg/kg, IV) were administered at 5-minute intervals until vomiting was observed. In a separate single-dose experiment, ascending doses of tranexamic acid (20, 30, 40, and 50 mg/kg, IV) were administered at 1-week intervals until vomiting was observed. Time to onset of vomiting and number of vomiting episodes were measured in both experiments. In a coagulation experiment, a single 50 mg/kg bolus of tranexamic acid was administered, and blood was obtained 1 hour before and 20 minutes, 3 hours, and 24 hours after administration. Antifibrinolytic potency of tranexamic acid was evaluated by use of a modified rotational thromboelastography method. Results—Tranexamic acid induced vomiting in a dose-dependent manner. Vomiting frequency was < 2 episodes, and vomiting concluded < 250 seconds after administration. Antifibrinolytic potency of tranexamic acid was significantly higher at 20 minutes following administration, but not different by 24 hours, when compared with the potency measured before administration. No adverse effects were observed in any experiment. Conclusions and Clinical Relevance—IV administration of tranexamic acid induced emesis in a dose-dependent manner. The antifibrinolytic potency of tranexamic acid decreased in a time-dependent manner and was resolved < 24 hours after administration. Further studies are warranted to investigate the emetic and other adverse effects of tranexamic acid in dogs of various breeds and ages.

Objective—To describe findings of 3.0-T multivoxel proton magnetic resonance spectroscopy (1H-MRS) in dogs with inflammatory and neoplastic intracranial disease and to determine the applicability of 1H-MRS for differentiating between inflammatory and neoplastic lesions and between meningiomas and gliomas. Animals—33 dogs with intracranial disease (19 neoplastic [10 meningioma, 7 glioma, and 2 other] and 14 inflammatory). Procedures—3.0-T multivoxel 1H-MRS was performed on neoplastic or inflammatory intracranial lesions identified with conventional MRI. N-acetylaspartate (NAA), choline, and creatine concentrations were obtained retrospectively, and metabolite ratios were calculated. Values were compared for metabolites separately, between lesion categories (neoplastic or inflammatory), and between neoplastic lesion types (meningioma or glioma) by means of discriminant analysis and 1-way ANOVA. Results—The NAA-to-choline ratio was 82.7% (62/75) accurate for differentiating neoplastic from inflammatory intracranial lesions. Adding the NAA-to-creatine ratio or choline-to-creatine ratio did not affect the accuracy of differentiation. Neoplastic lesions had lower NAA concentrations and higher choline concentrations than inflammatory lesions, resulting in a lower NAA-to-choline ratio, lower NAA-to-creatine ratio, and higher choline-to-creatine ratio for neoplasia relative to inflammation. No significant metabolite differences between meningiomas and gliomas were detected. Conclusions and Clinical Relevance—1H-MRS was effective for differentiating inflammatory lesions from neoplastic lesions. Metabolite alterations for 1H-MRS in neoplasia and inflammation in dogs were similar to changes described for humans. Use of 1H-MRS provided no additional information for differentiating between meningiomas and gliomas. Proton MRS may be a beneficial adjunct to conventional MRI in patients with high clinical suspicion of inflammatory or neoplastic intracranial lesions.

Objective—To evaluate the use of a micro-lightguide tissue spectrophotometer for measurement of tissue oxygenation and blood flow in the small and large intestines of horses under anesthesia. Animals—13 adult horses without gastrointestinal disease. Procedures—Horses were anesthetized and placed in dorsal recumbency. Ventral midline laparotomy was performed. Intestinal segments were exteriorized to obtain measurements. Spectrophotometric measurements of tissue oxygenation and regional blood flow of the jejunum and pelvic flexure were obtained under various conditions that were considered to have a potential effect on measurement accuracy. In addition, arterial oxygen saturation at the measuring sites was determined by use of pulse oximetry. Results—12,791 single measurements of oxygen saturation, relative amount of hemoglobin, and blood flow were obtained. Errors occurred in 381 of 12,791 (2.98%) measurements. Most measurement errors occurred when surgical lights were directed at the measuring site; covering the probe with the surgeon's hand did not eliminate this error source. No measurement errors were observed when the probe was positioned on the intestinal wall with room light, at the mesenteric side, or between the mesenteric and antimesenteric side. Values for blood flow had higher variability, and this was most likely caused by motion artifacts of the intestines. Conclusions and Clinical Relevance—The micro-lightguide spectrophotometry system was easy to use on the small and large intestines of horses and provided rapid evaluation of the microcirculation. Results indicated that measurements should be performed with room light only and intestinal motion should be minimized.

Objective-To determine whether increasing the viscosity of a standard hemoglobin-based oxygen-carrying solution (HBOC) would offset its associated vasoconstrictive effects and result in improved microvascular perfusion in healthy splenectomized dogs with experimentally induced hemorrhagic shock. Animals-12 male American Foxhounds. Procedures-Each dog underwent anesthesia and splenectomy. Shock was induced by controlled hemorrhage until a mean arterial blood pressure of 40 mm Hg was achieved and maintained for 60 minutes. Dogs were then randomly assigned to receive either a standard or hyperviscous HBOC (6 dogs/group). Sidestream dark-field microscopy was used to assess the effects of shock and HBOC administration on the microcirculation of the buccal mucosa and the jejunal serosa. Video recordings of the microcirculation were collected before shock was induced (baseline) and at intervals up to 180 minutes following HBOC administration. Vascular analysis software was used to compute microcirculatory variables. Results-Compared with baseline findings, hemorrhagic shock resulted in decreases in all microvascular variables in the buccal mucosa and the jejunal serosa. At all time points following HBOC administration, microvascular variables were similar to initial values and no significant differences between treatment groups were detected. At all time points following HBOC administration, blood and plasma viscosities in dogs treated with the hyperviscous solution were significantly higher than values in dogs receiving the standard solution. Conclusions and Clinical Relevance-In splenectomized dogs with experimentally induced hemorrhagic shock, administration of a hyperviscous HBOC did not significantly affect microvascular variables, compared with effects of a standard HBOC. Microcirculatory flow returned to baseline values in both treatment groups, suggesting that marked HBOC-associated vasoconstriction did not occur.

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 determine clinical sensitivity and specificity of a quantitative real-time PCR (qRT-PCR) assay for Campylobacter fetus subsp venerealis (Cfv) in preputial samples of bulls. Animals—313 beef bulls. Procedures—Preputial samples were collected from 300 virgin bulls and 13 Cfv-infected bulls. Specificity of the qRT-PCR assay, determined on the basis of results for samples collected from virgin bulls, was compared with specificity of bacteriologic culture performed with transport enrichment medium (TEM). Sensitivity of the qRT-PCR assay, determined on the basis of results for multiple samples collected at weekly intervals from infected bulls, was compared with sensitivity of the direct fluorescent antibody test (DFAT), bacteriologic culture, and bacteriologic culture with TEM. Results—Specificity was 85% for the qRT-PCR assay and 100% for bacteriologic culture; results were significantly different. Mean sensitivity was 85.4% for the qRT-PCR assay, 82.3% for direct culture in blood agar, 72.1% for the DFAT, 32.7% for direct culture in Skirrow agar, 30% for bacteriologic culture with TEM and blood agar, and 38.1% for bacteriologic culture with TEM and Skirrow agar. Differences in sensitivity among tests varied with ambient outdoor temperature. Repeated sampling significantly increased sensitivity of the qRT-PCR assay. Conclusions and Clinical Relevance—Use of the qRT-PCR assay as a screening test on direct preputial samples had comparable sensitivity to bacteriologic culture, and repeated sampling improved sensitivity. Although improved performance of the qRT-PCR assay, compared with direct bacteriologic culture, was dependent on temperature, transport times that allow direct culture are unlikely under field conditions. The qRT-PCR assay would provide a fast and sensitive screening method for Cfv in bulls.

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.

Objective-To evaluate intra-articular autologous protein solution (APS) for the treatment of osteoarthritis in horses. Animals-40 client-owned horses with naturally occuring osteoarthritis. Procedures-APS was generated from a dual-device system that concentrated plasma and WBC proteins and enriched platelet growth factors. Horses were randomly assigned to receive an intra-articular injection of 5 mL of saline (0.9% NaCl) solution (n = 20) or APS (20), exercised on a treadmill, and evaluated on the basis of lameness grades, kinetic gait analysis, joint circumference, and range of motion for 14 days. Horses that received saline solution were administered APS at termination of the study, and clients scored horses for lameness and discomfort before, 12 weeks after, and 52 weeks after the APS injection. Results-The APS group had significant improvements in lameness grade, asymmetry indices of vertical peak force, and range of joint motion by 14 days, compared with baseline or control group values. No adverse effects associated with APS treatment were evident. Clients assessed lameness and comfort as improved at 12 and 52 weeks. The APS had greater likelihood (OR, 4.3 to 30.0) of a therapeutic response in horses with a lameness score < 4, < 10% vertical force asymmetry, or absence of marked osteophyte formation, subchondral sclerosis, or joint space narrowing. Concentration of interleukin-1 receptor antagonist in APS was 5.8 times that in blood. Conclusions and Clinical Relevance-Intra-articular administration of APS can be considered an effective treatment option for equine osteoarthritis, with the potential for disease-modifying effects.

Objective—To determine the skin temperature of the metacarpus in horses associated with the use of bandages and tendon boots, compared with the bare limb, at rest and after 20 minutes of lunging. Animals—10 adult horses. Procedures—Skin temperature on the bare metacarpus of both forelimbs was measured at rest and after lunging. Subsequently, a bandage was applied to the left metacarpus and a tendon boot to the right metacarpus and skin temperature was measured at rest and after lunging. Skin temperature was measured with fixed sensors and thermographically. Results—Mean ± SD skin temperatures of the bare metacarpi were 14.1 ± 2.4°C (left) and 14.1 ± 3.4°C (right) at rest, and 14.4 ± 1.8°C (left) and 13.6 ± 2.6°C (right) after exercise. Skin temperatures under the bandage were 15.3 ± 1.6°C at rest and 24.8 ± 3.6°C after exercise. Skin temperatures under the tendon boot were 15.3 ± 2.6°C at rest and 20.6 ± 2.9°C after exercise. Skin temperatures under the bandage and tendon boot were significantly higher after exercise than at rest. Skin temperatures at rest were not significantly different with a bare limb, bandage, or tendon boot. Conclusions and Clinical Relevance—Skin temperature of the metacarpus in horses increased significantly during exercise but not at rest when a bandage or tendon boot was used. The authors speculate that both a bandage and a tendon boot accelerate the warmup phase of exercise. Further research should focus on the effects of warmup and maximum exercise on the temperature of other anatomic structures such as tendons.

Objective-To compare bronchoalveolar lavage (BAL) fluid obtained by manual aspiration (MA) with a handheld syringe with that obtained by suction pump aspiration (SPA) in healthy dogs. Animals-13 adult Beagles. Procedures-Each dog was anesthetized and bronchoscopic BAL was performed. The MA technique was accomplished with a 35-mL syringe attached to the bronchoscope biopsy channel. The SPA technique was achieved with negative pressure (5 kPa) applied to the bronchoscope suction valve with a disposable suction trap. Both aspiration techniques were performed in each dog in randomized order on opposite caudal lung lobes. Two 1 mL/kg aliquots of warm saline (0.9% NaCl) solution were infused per site. For each BAL fluid sample, the percentage of retrieved fluid was calculated, the total nucleated cell count (TNCC) and differential cell count were determined, and semiquantitative assessment of slide quality was performed. Comparisons were made between MA and SPA techniques for each outcome. Results-1 dog was removed from the study because of illness. The mean percentage of fluid retrieved (mean difference, 23%) and median TNCC (median distribution of differences, 100 cells/μL) for samples obtained by SPA were significantly greater than those for samples obtained by MA. Conclusions and Clinical Relevance-In healthy dogs, BAL by SPA resulted in a significantly higher percentage of fluid retrieval and samples with a higher TNCC than did MA. Further evaluation of aspiration techniques in dogs with respiratory tract disease is required to assess whether SPA improves the diagnostic yield of BAL samples.