OBJECTIVE To develop a novel method for use of diagnostic imaging, finite element analysis (FEA), and simulated biomechanical response behavior of brain tissue in noninvasive assessment and estimation of intracranial pressure (ICP) of dogs.
SAMPLE MRI data for 5 dogs.
PROCEDURES MRI data for 5 dogs (1 with a geometrically normal brain that had no detectable signs of injury or disease and 4 with various degrees of geometric abnormalities) were obtained from a digital imaging archiving and communication system database. Patient-specific 3-D models composed of exact brain geometries were constructed from MRI images. Finite element analysis was used to simulate and observe patterns of nonlinear biphasic biomechanical response behavior of geometrically normal and abnormal canine brains at various levels of decreasing cerebral perfusion pressure and increasing ICP.
RESULTS Changes in biomechanical response behavior were detected with FEA for decreasing cerebral perfusion pressure and increasing ICP. Abnormalities in brain geometry led to observable changes in deformation and biomechanical response behavior for increased ICP, compared with results for geometrically normal brains.
CONCLUSIONS AND CLINICAL RELEVANCE In this study, patient-specific critical ICP was identified, which could be useful as a method to predict the onset of brain herniation. Results indicated that it was feasible to apply FEA to brain geometry obtained from MRI data of clinical patients and to use biomechanical response behavior resulting from increased ICP as a diagnostic and prognostic method to noninvasively assess or classify levels of brain injury in clinical veterinary settings.
OBJECTIVE To compare effectiveness of glycerol, dimethyl sulfoxide (DMSO), and hydroxyethyl starch (HES) solutions for cryopreservation of avian RBCs.
SAMPLE RBCs from 12 healthy Ameraucana hens (Gallus gallus domesticus).
PROCEDURES RBCs were stored in 20% (wt/vol) glycerol, 10% (wt/vol) DMSO freezing medium, or various concentrations of HES solution (7.5%, 11.5%, and 20% [wt/vol]) and frozen for 2 months in liquid nitrogen. Cells were then thawed and evaluated by use of cell recovery and saline stability tests, cell staining (7-aminoactinomycin D and annexin V) and flow cytometry, and scanning electron microscopy.
RESULTS Percentage of RBCs recovered was highest for 20% glycerol solution (mean ± SE, 99.71 ± 0.04%) and did not differ significantly from the value for 7.5% HES solution (99.57 ± 0.04%). Mean saline stability of RBCs was highest for 10% DMSO (96.11 ± 0.25%) and did not differ significantly from the value for 20% HES solution (95.74 ± 0.25%). Percentages of cells with 7-aminoactinomycin D staining but without annexin V staining (indicating necrosis or late apoptosis) were lowest for 10% DMSO freezing medium (3%) and 20% glycerol solution (1%) and highest for all HES concentrations (60% to 80%). Scanning electron microscopy revealed severe membrane changes in RBCs cryopreserved in 20% HES solution, compared with membrane appearance in freshly harvested RBCs and RBCs cryopreserved in 10% DMSO freezing medium.
CONCLUSIONS AND CLINICAL RELEVANCE Cryopreservation of avian RBCs with HES solution, regardless of HES concentration, resulted in greater degrees of apoptosis and cell death than did cryopreservation with other media. Transfusion with RBCs cryopreserved in HES solution may result in posttransfusion hemolysis in birds.
OBJECTIVE To evaluate the use of rebound and applanation tonometry for the measurement of intraocular pressure (IOP) and to assess diurnal variations in and the effect of topical anesthesia on the IOP of healthy inland bearded dragons (Pogona vitticeps).
ANIMALS 56 bearded dragons from 4 months to 11 years old.
PROCEDURES For each animal following an initial ophthalmic examination, 3 IOP measurements were obtained on each eye between 9 AM and 10 AM, 1 PM and 2 PM, and 5 PM and 7 PM by use of rebound and applanation tonometry. An additional measurement was obtained by rebound tonometry for each eye in the evening following the application of a topical anesthetic to evaluate changes in the tolerance of the animals to the tonometer. Descriptive data were generated, and the effects of sex, time of day, and topical anesthesia on IOP were evaluated.
RESULTS Bearded dragons did not tolerate applanation tonometry even following topical anesthesia. Median daily IOP as determined by rebound tonometry was 6.16 mm Hg (95% confidence interval, 5.61 to 6.44 mm Hg). The IOP did not differ significantly between the right and left eyes. The IOP was highest in the morning, which indicated that the IOP in this species undergoes diurnal variations. Topical anesthesia did not significantly affect IOP, but it did improve the compliance for all subjects.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that rebound tonometry, but not applanation tonometry, was appropriate for measurement of IOP in bearded dragons. These findings provided preliminary guidelines for IOP measurement and ophthalmic evaluation in bearded dragons.
Objective—To determine whether thromboelastography is more accurate than conventional methods of evaluating hemostasis for the prediction of clinical bleeding in thrombocytopenic dogs following total body irradiation (TBI) and bone marrow transplantation (BMT).
Animals—10 client-owned thrombocytopenic dogs with multicentric lymphoma.
Procedures—Results of a kaolin-activated thromboelastography assay, platelet count, and buccal mucosal bleeding time were evaluated for correlation to clinical bleeding.
Results—Maximum amplitude, derived via thromboelastography, was the only hemostatic variable with significant correlation to clinical bleeding. Buccal mucosal bleeding time had a high sensitivity but poor specificity for identifying dogs with clinical bleeding.
Conclusions and Clinical Relevance—Compared with buccal mucosal bleeding time and platelet count, thromboelastography was more reliable at identifying thrombocytopenic dogs with a low risk of bleeding and could be considered to help guide the use of transfusion products in dogs undergoing TBI and BMT.
Objective—To determine the effects of protease inhibitors and holding times and temperatures before processing on the stability of substance P in bovine blood samples.
Samples—Blood samples obtained from a healthy 6-month-old calf.
Procedures—Blood samples were dispensed into tubes containing exogenous substance P and 1 of 6 degradative enzyme inhibitor treatments: heparin, EDTA, EDTA with 1 of 2 concentrations of aprotinin, or EDTA with 1 of 2 concentrations of a commercially available protease inhibitor cocktail. Plasma was harvested immediately following collection or after 1, 3, 6, 12, or 24 hours of holding at ambient (20.3° to 25.4°C) or ice bath temperatures. Total substance P immunoreactivity was determined with an ELISA; concentrations of the substance P parent molecule, a metabolite composed of the 9 terminal amino acids, and a metabolite composed of the 5 terminal amino acids were determined with liquid chromatography–tandem mass spectrometry.
Results—Regarding blood samples processed immediately, no significant differences in substance P concentrations or immunoreactivity were detected among enzyme inhibitor treatments. In blood samples processed at 1 hour of holding, substance P parent molecule concentration was significantly lower for ambient temperature versus ice bath temperature holding conditions; aprotinin was the most effective inhibitor of substance P degradation at the ice bath temperature. The ELISA substance P immunoreactivity was typically lower for blood samples with heparin versus samples with other inhibitors processed at 1 hour of holding in either temperature condition.
Conclusions and Clinical Relevance—Results suggested that blood samples should be chilled and plasma harvested within 1 hour after collection to prevent substance P degradation.
Objective—To evaluate the accuracy of digitally scanned rhodanine-stained liver biopsy specimens for determination of hepatic copper concentration and compare results with qualitatively assigned histologic copper scores in dogs.
Sample—353 liver biopsy specimens from dogs.
Procedures—Specimens (n = 139) with quantified copper concentration ranging from 93 to 6,900 μg/g were allocated to group 1 (< 400 μg/g ), group 2 (401 to 1,000 μg/g ), group 3 (1,001 to 2,000 μg/g ), and group 4 (> 2,001 μg/g ); stained with rhodanine; and digitally scanned and analyzed with a proprietary positive pixel algorithm. Measured versus calculated copper concentrations were compared, and limits of agreement determined. Influence of nodular remodeling, fibrosis, or parenchymal loss on copper concentration was determined by digitally analyzing selected regions in 17 specimens. After method validation, 214 additional liver specimens underwent digital scanning for copper concentration determination. All sections (n = 353) were then independently scored by 2 naive evaluators with a qualitative scoring schema. Agreement between assigned scores and between assigned scores and tissue copper concentrations was determined.
Results—Linear regression was used to develop a formula for calculating hepatic copper concentration ≥ 400 μg/g from scanned sections. Copper concentrations in unremodeled specimens were significantly higher than in remodeled specimens. Qualitative scores widely overlapped among quantitative copper concentration groups.
Conclusions and Clinical Relevance—Calculated copper concentrations determined by means of digital scanning of rhodanine-stained liver sections were highly correlated with measured values and more accurate than qualitative copper scores, which should improve diagnostic usefulness of hepatic copper concentrations and assessments in sequential biopsy specimens.
Objective—To determine the optimal method for use of the Canine Brief Pain Inventory (CBPI) to quantitate responses of dogs with osteoarthritis to treatment with carprofen or placebo.
Animals—150 dogs with osteoarthritis.
Procedures—Data were analyzed from 2 studies with identical protocols in which owner-completed CBPIs were used. Treatment for each dog was classified as a success or failure by comparing the pain severity score (PSS) and pain interference score (PIS) on day 0 (baseline) with those on day 14. Treatment success or failure was defined on the basis of various combinations of reduction in the 2 scores when inclusion criteria were set as a PSS and PIS ≥ 1, 2, or 3 at baseline. Statistical analyses were performed to select the definition of treatment success that had the greatest statistical power to detect differences between carprofen and placebo treatments.
Results—Defining treatment success as a reduction of ≥ 1 in PSS and ≥ 2 in PIS in each dog had consistently robust power. Power was 62.8% in the population that included only dogs with baseline scores ≥ 2 and 64.7% in the population that included only dogs with baseline scores ≥ 3.
Conclusions and Clinical Relevance—The CBPI had robust statistical power to evaluate the treatment effect of carprofen in dogs with osteoarthritis when protocol success criteria were predefined as a reduction ≥ 1 in PIS and ≥ 2 in PSS. Results indicated the CBPI can be used as an outcome measure in clinical trials to evaluate new pain treatments when it is desirable to evaluate success in individual dogs rather than overall mean or median scores in a test population.
Objective—To compare β-hydroxybutyrate (BHB) and glucose concentrations measured with a dual-purpose point-of-care (POC) meter designed for use in humans and a laboratory biochemical analyzer (LBA) to determine whether the POC meter would be reliable for on-farm measurement of blood glucose and BHB concentrations in sheep in various environmental conditions and nutritional states.
Animals—36 pregnant mixed-breed ewes involved in a maternal feed restriction study.
Procedures—Blood samples were collected from each sheep at multiple points throughout gestation and lactation to allow for tracking of gradually increasing metabolic hardship. Whole blood glucose and BHB concentrations were measured with the POC meter and compared with serum results obtained with an LBA.
Results—464 samples were collected. Whole blood BHB concentrations measured with the POC meter compared well with LBA results, and error grid analysis showed the POC values were acceptable. Whole blood glucose concentrations measured with the POC meter had more variation, compared with LBA values, over the glucose ranges evaluated. Results of error grid analysis of POC-measured glucose concentrations were not acceptable, indicating errors likely to result in needless treatment with glucose or other supplemental energy sources in normoglycemic sheep.
Conclusions and Clinical Relevance—The POC meter was user-friendly and performed well across a wide range of conditions. The meter was adequate for detection of pregnancy toxemia in sheep via whole blood BHB concentration. Results should be interpreted with caution when the POC meter is used to measure blood glucose concentrations.
Objective—To compare the recovery rates of Campylobacter fetus subsp venerealis (Cfv) from preputial scrapings of infected bulls with passive filtration on selective medium versus nonselective medium, with and without transport medium.
Samples—217 preputial scrapings from 12 bulls (4 naturally and 8 artificially infected with Cfv).
Procedures—Preputial scrapings were collected in 2 mL of PBS solution and bacteriologically cultured directly on Skirrow medium or passively filtered through 0.65-μm filters onto blood agar, with or without 24 hour preincubation in modified Weybridge transport enrichment medium (TEM). After 72 hours, plates were examined for Cfv and bacterial and fungal contamination or overgrowth.
Results—Passive filtration of fresh preputial scrapings onto blood agar yielded significantly higher recovery rates of Cfv (86%) than direct plating on Skirrow medium (32%), whereas recovery from TEM was poor for both media (35% and 40%, respectively). Skirrow cultures without TEM were significantly more likely to have fungal contamination than were cultures performed with any other technique, and fungal contamination was virtually eliminated by passive filtration onto blood agar. Bacterial contamination by Pseudomonas spp was significantly more common with Skirrow medium versus passive filtration on blood agar, regardless of TEM use.
Conclusions and Clinical Relevance—The use of transport medium and the choice of culture medium had significant effects on Cfv recovery and culture contamination rates from clinical samples. Both factors should be considered when animals are tested for this pathogen.
Objective—To compare the diagnostic quality of bronchoalveolar lavage (BAL) fluid acquired from healthy dogs by manual aspiration via polyethylene tubing (MAPT) and via suction pump aspiration (SPA) with a suction trap connection.
Animals—12 healthy adult Beagles.
Procedures—BAL was performed with bronchoscopic guidance in anesthetized dogs. The MAPT was performed with a 35-mL syringe attached to polyethylene tubing wedged in a bronchus via the bronchoscope's biopsy channel. The SPA was performed with 5 kPa of negative pressure applied to the bronchoscope's suction valve via a suction trap. The MAPT and SPA techniques were performed in randomized order on opposite caudal lung lobes of each dog. Two 1 mL/kg lavages were performed per site. Samples of BAL fluid were analyzed on the basis of a semiquantitative quality scale, percentage of retrieved fluid, and total nucleated and differential cell counts. Results were compared with Wilcoxon signed rank tests.
Results—Percentage of BAL fluid retrieved (median difference, 16.2%), surfactant score (median difference, 1), and neutrophil count (median difference, 74 cells/μL) were significantly higher for SPA than for MAPT. A higher BAL fluid epithelial cell score was obtained via MAPT, compared with that for samples obtained via SPA (median difference, 1).
Conclusions and Clinical Relevance—Results indicated that in healthy dogs, SPA provided a higher percentage of BAL fluid retrieval than did MAPT. The SPA technique may improve the rate of diagnostic success for BAL in dogs, compared with that for MAPT. Further evaluation of these aspiration techniques in dogs with respiratory tract disease is required.