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Abstract

Objective—To compare the use of a semi-invasive vascular access port (VAP) device or noninvasive oscillometry versus invasive telemetry for blood pressure measurements in cats.

Animals—6 healthy cats.

Procedures—30 days before the study, all cats received an implanted telemeter and a VAP device. During normotension and experimentally induced hypertension, blood pressure was measured with the implanted devices and with noninvasive oscillometry at 4 time points.

Results—Compared with invasive telemetry, VAP had a correlation coefficient from 0.8487 to 0.9972, and noninvasive oscillometry had a correlation coefficient from 0.7478 to 0.9689.

Conclusions and Clinical Relevance—Use of the VAP device and noninvasive oscillometry had a high degree of correlation with invasive telemetry as the gold standard for blood pressure measurement. Use of a VAP device resulted in a slightly higher degree of correlation, compared with noninvasive oscillometry.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To investigate whether an accelerometer-based activity monitor could be used in pet dogs to differentiate among and delineate the amount of time spent in activities of differing intensity.

Animals—104 dogs.

Procedures—For the first phase of the study, each dog (n = 104) wore an accelerometer-based activity monitor and was led through a series of standard activities (recumbency [sedentary], walking, and trotting). Receiver operating characteristic curves were generated to determine the optimal activity counts for predicting whether a dog was sedentary, walking, or trotting. For the second phase of the study, dogs (n = 99) wore an activity monitor on their collars continuously for 14 days at home; intensity of activity for each dog was classified by use of cut points determined on the basis of results obtained during the first phase of the study.

Results—Analysis of receiver operating characteristic curves indicated that there was 100% specificity and 100% sensitivity in distinguishing sedentary activity from walking activity and 92% specificity and 92% sensitivity in distinguishing trotting activity from walking activity. Analysis of data collected during the 14-day period at home indicated that dogs were sedentary most of the time (median, 87%; range, 65% to 95%).

Conclusions and Clinical Relevance—Counts recorded by an accelerometer-based activity monitor could be used to discriminate effectively among standardized activities in pet dogs. There is potential for use of the method to improve the ability of clinicians and researchers to accurately estimate a pet dog's daily energy requirement.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of syringomyelia on electromyography (EMG) findings, somatosensory-evoked potentials (SEPs), and transcranial magnetic motor-evoked potentials (TMMEPs) in Cavalier King Charles Spaniels (CKCSs).

Animals—27 client-owned CKCSs that underwent prebreeding magnetic resonance imaging screening or investigation of clinical signs consistent with syringomyelia.

Procedures—In dogs with (n = 11) and without (16) magnetic resonance imaging-confirmed syringomyelia, the median nerve in each thoracic limb was stimulated and SEPs were recorded over the C1 vertebra; onset latency and latency and amplitude of the largest negative (N1) and positive (P1) peaks were measured. The TMMEPs were recorded bilaterally from the extensor carpi radialis and tibialis cranialis muscles; onset latencies in all 4 limbs were measured. Bilateral systematic needle EMG examination was performed on the cervical epaxial musculature, and the number of sites with spontaneous activity was recorded.

Results—In dogs with syringomyelia, amplitudes of N1 and P1 and the amplitude difference between P1 and N1 were significantly smaller than those recorded for dogs without syringomyelia (approx 2-fold difference). No difference in SEP latencies, TMMEP latencies, or the proportion of dogs with > 2 sites of spontaneous activity detected during EMG examination was detected between groups.

Conclusions and Clinical Relevance—Results indicated that SEP amplitude at the C1 vertebra was a more sensitive measure of spinal cord function in CKCSs with syringomyelia, compared with results of EMG or TMMEP assessment. Measurement of SEP amplitude may have use as an objective assessment of the evolution and treatment of this disease.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To directly assess microcirculatory changes associated with induced hemorrhagic shock by use of sidestream dark field microscopy (SDM) and correlate those values with concurrently measured macrovascular and blood gas variables in healthy anesthetized dogs.

Animals—12 adult dogs.

Procedures—Dogs were anesthetized and splenectomized. Instrumentation and catheterization were performed for determination of macrohemodynamic and blood gas variables. Hemorrhagic shock was induced via controlled hemorrhage to a mean arterial blood pressure (MAP) of 40 mm Hg. Dogs were maintained in the shock state (MAP, 35 to 45 mm Hg) for 60 minutes. An SDM device was used to image microcirculation of buccal mucosa, and vascular analysis software was used to determine microcirculatory variables. These values were compared with other cardiovascular and blood gas variables to determine correlations.

Results—Following hemorrhage, there was a significant decrease in microvascular variables (mean ± SD), including proportion of perfused vessels (82.77 ± 8.32% vs 57.21 ± 28.83%), perfused vessel density (14.86 ± 2.64 mm/m2 vs 6.66 ± 4.75 mm/m2), and microvascular flow index (2.54 ± 0.52 vs 1.59 ± 0.85). Perfused vessel density individually correlated well with macrovascular variables, with heart rate (zero order, partial correlation, and part correlation coefficients = −0.762, −0.884, and −0.793, respectively) and oxygen extraction ratio (−0.734, −0.832, and −0.746, respectively) being the most important predictors.

Conclusions and Clinical Relevance—SDM allowed real-time imaging of the microvasculature and has potential as an effective tool in experimental and clinical applications for monitoring microcirculatory changes associated with hemorrhagic shock and resuscitation in dogs.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare results of body condition scoring by use of a 9-point scale with body composition determined by dual-energy x-ray absorptiometry (DEXA) in indoor-confined neutered domestic shorthair (DSH) pet cats.

Animals—72 indoor-confined, adult neutered DSH pet cats (38 females and 34 males).

Procedures—All cats underwent a physical examination including assessment of body weight (BW), body condition score (BCS; 1 = emaciated, 5 = ideal, and 9 = grossly obese), and girth. Urinalysis, CBC, and serum biochemical analysis were also performed. After the cats were confirmed healthy, they were anesthetized for body composition measurement via DEXA. Lean body mass, fat mass, and percentage body fat (%BF) were then evaluated.

Results—The correlation between %BF and BCS (r = 0.87) was superior to the correlations between %BFand BW (r = 0.74) and between %BF and girth (r = 0.78). Values for %BF differed significantly between all pairs of BCSs except BCSs 8 and 9. Within a BCS, the %BF was similar for male and female cats. The mean %BF for cats with a BCS of 5 was 32, which exceeded the upper reference limit of %BF generally considered ideal (30).

Conclusions and Clinical Relevance—The 9-point BCS scale appears useful for assessing %BF in DSH pet cats. Nevertheless, study findings could indicate a need for redefining the ideal BCS for inactive neutered cats to include a BCS of 4.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate distortion product otoacoustic emission (DPOAE) measurements in puppies with normal hearing.

Animals—23 clinically normal 7.5-to 10.5-week-old puppies.

Procedures—A cross-sectional study was performed. The DPOAE measurements were obtained with a commercially available distortion product otoacoustic measurement system and were performed in a quiet, non-sound-attenuated room. All measurements were obtained from alert puppies and were repeated 1 or 2 times to ensure that the measurements were replicable. Results that were a minimum of 8 dB higher than the noise floor were accepted. Values from the first trial in which emissions were obtained at all test frequencies were used for analysis.

Results—Otoacoustic emission measurements were easily obtained, robust, reliable, and consistent with auditory brainstem response and behavioral results.

Conclusions and Clinical Relevance—Hearing screening in alert puppies can be accomplished reliably and rapidly with otoacoustic emissions testing. Results supported the possibility of the use of DPOAE measurement in hearing screening of dogs.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess the in vitro capability of aqueous black walnut extracts (BWEs) to generate reactive oxygen species in water-based media ranging in makeup from a simple buffer solution to a complex solution containing serum.

Sample—3 BWEs.

Procedures—Production of reactive oxygen species by BWEs prepared in water or N-hexane was tested in PBS solution, PBS solution containing 0.5% bovine serum albumin and 5mM glucose (PBG), and RPMI-1640 medium (RPMI) containing 10% fetal bovine serum or 10% donor horse serum. Reactive oxygen species production was measured as conversion of nonfluorescent dihydrorhodamine 123 by reactive oxygen species to its fluorescent product, rhodamine-123. Hydrogen peroxide was used as a standard for reactive oxygen species activity.

Results—BWEs prepared in water generated reactive oxygen species in a dose-dependent manner over a 4-hour period, with peak activity detected when the BWEs were added as 10% (vol/vol) of the RPMI. The BWE prepared in N-hexane generated maximal reactive oxygen species activity after incubation for 3 to 4 hours when added at concentrations ranging from 0.3% to 0.5% (vol/vol) of the RPMI. The BWE prepared in water generated the highest fluorescent signal in PBS solution, whereas the BWE prepared in N-hexane generated the highest fluorescent signal in PBG.

Conclusions and Clinical Relevance—The BWEs prepared in water generated a dose-dependent induction of fluorescence in all the water-based solutions tested. These findings indicated that the BWEs, which are used to induce laminitis in horses, generate reactive oxygen species.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate effects of black walnut extract (BWE) on equine mononuclear cells and determine whether BWE has direct proinflammatory effects.

Sample—Mononuclear cells separated from blood samples from 8 horses.

Procedures—Aqueous BWE was prepared and processed to eliminate contamination with particulates and microbes. A Limulus amoebocyte lysate assay was used to detect lipopolysaccharide (LPS) contamination in the BWE. Mononuclear cells were incubated in minimal essential medium with or without the addition of 0.6% to 10% (vol/vol) BWE. These mononuclear cells were assessed for viability, activities of caspases 3 and 7, nitric oxide production, procoagulant activity, and tumor necrosis factor-α production. The effect of LPS on cellular responses induced by BWE was assessed by coincubation with 13 U of polymyxin B/mL; mononuclear cells incubated with LPS were used as a reference.

Results—BWE did not cause loss of cell membrane integrity in mononuclear cells but did induce a dose-dependent increase in activities of caspases 3 and 7. Neither BWE nor LPS significantly induced production of nitric oxide. Both BWE and LPS induced comparable amounts of procoagulant activity and tumor necrosis factor-α production; coincubation with polymyxin B reduced the activity for BWE and LPS by 50% and approximately 100%, respectively.

Conclusions and Clinical Relevance—Addition of BWE induced inflammatory activation of equine mononuclear cells, a portion of which was independent of the effects of LPS. Furthermore, BWE and LPS may work in concert to induce systemic inflammatory responses that contribute to the development of acute laminitis in horses.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the specificity of a canine pancreas-specific lipase (cPSL) assay for diagnosing pancreatitis in dogs without clinical or histologic evidence of the disease.

Animals—20 dogs from another study with macroscopic evidence of pancreatitis and 44 dogs surrendered for euthanasia or expected to die.

Procedures—Prior to death, physical examination of each dog was performed and blood samples were collected for serum biochemical, serum cPSL, and hematologic analyses. After death, the pancreas was removed, sectioned in 1- to 2-cm slices, and evaluated by a pathologist. Dogs were classified by whether they had clinical or macroscopic pancreatitis. Each pancreatic section was histologically examined, and mean cumulative scores (MCSs) were assigned for 8 histologic characteristics. For each characteristic, comparisons were made between dogs with and without pancreatitis to establish histologic criteria for lack of evidence of pancreatitis.

Results—For all histologic characteristics except lymphocytic infiltration, the median MCS differed significantly between dogs with and without pancreatitis. Dogs were categorized as having no histologic evidence of pancreatitis when the MCSs for neutrophilic infiltration, pancreatic necrosis, peripancreatic fat necrosis, and edema were 0.0. On the basis of these criteria, 40 dogs were classified as having no evidence of pancreatitis. The cPSL concentration was within reference limits in 38 of these 40 dogs and was less than the cutoff value for diagnosing pancreatitis (400 μg/L) in 39 of the 40 dogs, resulting in a specificity of 97.5% (95% confidence interval, 86.8% to 99.9%).

Conclusions and Clinical Relevance—The cutoff cPSL value used in this study may be useful for diagnosing pancreatitis in dogs with a lack of histologic lesions consistent with pancreatitis and for which pancreatitis is not considered a major differential diagnosis.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate 5 commercially available ELISAs for determination of leptin concentrations in serum samples from dogs.

Sample Population—Serum samples from overweight-obese and thin–ideal weight clientowned dogs.

Procedures—Serum samples with high and low leptin concentrations (n = 7 samples each) were used for validation of the assays. Intra- and interassay precision, linearity under dilution, spiking recovery, and limit of quantification were determined. In addition, leptin concentrations in thin–ideal weight (n = 8) and overweight-obese (37) dogs were quantified.

Results—Use of 2 of the 5 ELISAs (A and B) revealed reactivity with canine leptin. Intra-and interassay coefficients of variation were < 6.1% and 76%, respectively, for assay A and 14.0% and 13.7%, respectively, for assay B. In assays A and B, dilutions of canine serum pools were used to determine linear regression equations. Recoveries were 77% to 101% for assay A and 67% to 125% for assay B. Significant differences in leptin concentrations between thin–ideal weight and overweight-obese dogs were detected only when analyzed with assay A.

Conclusions and Clinical Relevance—Among 5 leptin ELISAs evaluated, a canine-specific leptin ELISA had adequate precision, linearity, and ability to discriminate between high and low leptin concentrations corresponding to overweight-obese and thin–ideal weight dogs, respectively.

Full access
in American Journal of Veterinary Research