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Abstract
OBJECTIVE
To compare urine concentrations of fibrinogen (uFIB) and interleukin-6 (uIL-6) between dogs with risk factors for enterococcal bacteriuria and healthy dogs.
SAMPLE
Banked urine samples with negative aerobic culture results from 8 dogs with urolithiasis, 9 dogs with anatomic abnormalities of the lower portion of the urinary tract (LUT), 10 dogs with LUT neoplasia, and 21 healthy control dogs.
PROCEDURES
Urine creatinine concentration (uCrea) was determined by an automated biochemical analyzer, and uFIB and uIL-6 were determined by dog-specific ELISAs. The uFIB:uCrea and uIL-6:uCrea ratios were calculated for each sample to normalize intersample differences in urine concentration and were compared among the 4 experimental groups.
RESULTS
Median uFIB:uCrea ratios for dogs with urolithiasis (0.72; interquartile [25th to 75 percentile] range [IQR], 0.46 to 3.48) and LUT neoplasia (6.16; IQR, 3.89 to 12.75), but not for dogs with LUT anatomic abnormalities (0.48; IQR, 0.27 to 0.69), were significantly greater than that for control dogs (0.17; IQR, 0.07 to 0.39). Median uIL-6:uCrea ratios for dogs with urolithiasis (0.48; IQR, 0.18 to 1.61), LUT anatomic abnormalities (0.25; IQR, 0.17 to 0.33), and LUT neoplasia (0.25; IQR, 0.12 to 1.01) were significantly greater than that for control dogs (0.08; IQR, 0.06 to 0.11).
CONCLUSIONS AND CLINICAL RELEVANCE
The uFIB and uIL-6 in dogs with risk factors for enterococcal bacteriuria were generally greater than corresponding values in control dogs. Further investigation is necessary to determine the role of fibrinogen in enterococcal colonization of the urinary tract of dogs.
Abstract
OBJECTIVE
To use RNA sequencing (RNAseq) to characterize renal transcriptional activities of genes associated with proinflammatory and profibrotic pathways in ischemia-induced chronic kidney disease (CKD) in cats.
SAMPLES
Banked renal tissues from 6 cats with experimentally induced CKD (renal ischemia [RI] group) and 9 healthy cats (control group).
PROCEDURES
Transcriptome analysis with RNAseq, followed by gene ontology and cluster analyses, were performed on banked tissue samples of the right kidneys (control kidneys) from cats in the control group and of both kidneys from cats in the RI group, in which unilateral (right) RI had been induced 6 months before the cats were euthanized and the ischemic kidneys (IKs) and contralateral nonischemic kidneys (CNIKs) were harvested. Results for the IKs, CNIKs, and control kidneys were compared to identify potential differentially expressed genes and overrepresented proinflammatory and profibrotic pathways.
RESULTS
Genes from the gene ontology pathways of collagen binding (eg, transforming growth factor-β1), metalloendopeptidase activity (eg, metalloproteinase [MMP]-7, MMP-9, MMP-11, MMP-13, MMP-16, MMP-23B, and MMP-28), chemokine activity, and T-cell migration were overrepresented as upregulated in tissue samples of the IKs versus control kidneys. Genes associated with the extracellular matrix (eg, TIMP-1, fibulin-1, secreted phosphoprotein-1, matrix Gla protein, and connective tissue growth factor) were upregulated in tissue samples from both the IKs and CNIKs, compared with tissues from the control kidneys.
CONCLUSIONS AND CLINICAL RELEVANCE
Unilateral ischemic injury differentially altered gene expression in both kidneys, compared with control kidneys. Fibulin-1, secreted phosphoprotein-1, and matrix Gla protein may be candidate biomarkers of active kidney injury in cats.
Abstract
OBJECTIVE
To evaluate a novel 2-catheter technique for urethral catheterization in female cats and small dogs and compare the time required for and success rates achieved by use of the novel technique versus traditional methods (blind technique in cats and digital palpation in dogs) as performed by personnel (catheter placers [CPs]) with different levels of experience in urinary catheter placement.
ANIMALS
39 healthy sexually intact female animals (24 cats and 15 dogs weighing < 10 kg).
PROCEDURES
2 CPs were board certified in veterinary surgery, 1 of whom had experience with the novel technique, and the other did not. The third CP was a veterinary surgical intern who was unfamiliar with the novel technique. For each animal enrolled in the study, 1 CP performed catheterization with the novel technique and traditional methods. Data recorded included the time required for successful catheterization and whether a successful catheterization was achieved within a 3-minute time limit.
RESULTS
The overall success rates were 79.5% (31/39 animals) with the novel technique and 43.6% (17/39 animals) with traditional methods. Median times for successful catheter placement were 48 seconds for the novel technique and 41 seconds for traditional methods. Among CPs, success rates or times to successful catheter placement did not differ significantly.
CONCLUSIONS AND CLINICAL RELEVANCE
Study results suggested that the novel 2-catheter technique for urethral catheterization may be a more efficient option than traditional methods for gaining access to the urinary bladder in cats and small dogs, particularly when patient size limits use of instrumentation or digital palpation.
Abstract
OBJECTIVE
To establish a reference interval for glomerular filtration rate (GFR) determined by measuring serum clearance of a single IV dose of inulin in clinically normal cheetahs (Acinonyx jubatus) and compare serum symmetric dimethylarginine (SDMA) concentration in cheetahs with GFR.
ANIMALS
33 cheetahs housed at 3 institutions.
PROCEDURES
A single bolus of inulin (3,000 mg/m2) was administered IV, and 5 serial blood samples were collected and analyzed for serum inulin concentration with the anthrone technique. The GFR was estimated with a modified slope-intercept method for the slow component of the serum concentration-versus-time curve. Blood urea nitrogen and serum creatinine concentrations were measured in samples obtained immediately prior to inulin administration, and serum SDMA concentration was measured in stored samples.
RESULTS
Mean ± SD measured GFR was 1.58 ± 0.39 mL/min/kg, and the calculated reference interval was 0.84 to 2.37 mL/min/kg. There were significant negative correlations between GFR and serum creatinine concentration (r = −0.499), BUN concentration (r = −0.592), and age (r = −0.463). Serum SDMA concentration was not significantly correlated with GFR (r = 0.385), BUN concentration (r = −0.281), or serum creatinine concentration (r = 0.165).
CONCLUSIONS AND CLINICAL RELEVANCE
A reference interval for GFR in clinically normal cheetahs was obtained. Further evaluation of animals with renal disease is needed to determine whether measuring serum clearance of a single IV dose of inulin is a reliable diagnostic test for early detection of renal disease in cheetahs.
Abstract
OBJECTIVE
To characterize transcription of profibrotic mediators in renal tissues of cats with ischemia-induced chronic kidney disease (CKD).
SAMPLE
Banked renal tissues from 6 cats with experimentally induced CKD (RI group) and 8 healthy control cats.
PROCEDURES
For cats of the RI group, both kidneys were harvested 6 months after ischemia was induced for 90 minutes in 1 kidney. For control cats, the right kidney was evaluated. All kidney specimens were histologically examined for fibrosis, inflammation, and tubular atrophy. Renal tissue homogenates underwent reverse transcription quantitative PCR assay evaluation to characterize gene transcription of hypoxia-inducible factor-1α (HIF-1α), matrix metalloproteinase (MMP)-2, MMP-7, MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), transforming growth factor-β1, and vascular endothelial growth factor A. Gene transcription and histologic lesions were compared among ischemic and contralateral kidneys of the RI group and control kidneys.
RESULTS
Ischemic kidneys had greater transcript levels of MMP-7, MMP-9, and transforming growth factor-β1 relative to control kidneys and of MMP-2 relative to contralateral kidneys. Transcription of TIMP-1 was upregulated and that of vascular endothelial growth factor A was downregulated in ischemic and contralateral kidneys relative to control kidneys. Transcription of HIF-1α did not differ among kidney groups. For ischemic kidneys, there were strong positive correlations between transcription of HIF-1α, MMP-2, MMP-7, and TIMP-1 and severity of fibrosis.
CONCLUSIONS AND CLINICAL RELEVANCE
Transcription of genes involved in profibrotic pathways remained altered in both kidneys 6 months after transient renal ischemia. This suggested that a single unilateral renal insult can have lasting effects on both kidneys.
Abstract
OBJECTIVE
To quantify the magnitude and duration of changes in urine chondroitin sulfate concentration (uCS) as a result of oral administration of a chondroitin sulfate–containing supplement in dogs.
ANIMALS
8 healthy privately owned dogs.
PROCEDURES
A urine sample was collected from each dog via cystocentesis on day 1; free-catch midstream urine samples were collected once daily on days 2 through 5. Pretreatment uCS was established from those samples. Each dog then received a chondroitin sulfate–containing supplement (20 to 30 mg/kg, PO, q 12 h) for 8 days (on days 7 through 14). Urine samples were collected on days 8 through 12 and day 15. For each sample, uCS was quantified by liquid chromatography–tandem mass spectrometry. Variable urine concentration was accounted for by dividing the uCS by urine creatinine concentration (uCrea) to determine the uCS:uCrea ratio. Pretreatment uCS:uCrea ratios were compared with treatment uCS:uCrea ratios to calculate the fold change in uCS after supplement administration.
RESULTS
Among the study dogs, oral administration of the chondroitin sulfate–containing supplement resulted in a 1.9-fold increase in the median uCS:uCrea ratio. Data obtained on days 8 through 12 and day 15 indicated that the daily increase in uCS remained consistent and was not additive.
CONCLUSIONS AND CLINICAL RELEVANCE
Results indicated that oral administration of supplemental chondroitin sulfate to dogs modestly increased uCS within 24 hours; however, subsequent supplement administration did not have an additive effect. A potential therapeutic benefit of persistently increased uCS in preventing recurrent urinary tract infections in dogs warrants investigation.
Abstract
OBJECTIVE
To evaluate agreement of 4 methods (Tikhonov gamma variate adaptive regularization of plasma concentration-time curve fitting applied to technetium Tc 99m diethylenetriamine pentaacetic acid [99mTc-DTPA] plasma clearance [Tk-GV], plasma clearance of exogenous creatinine [CrCL], Gates gamma camera-based measurement method with 99mTc-DTPA renal clearance and dynamic scintigraphy [GTS], and iohexol renal clearance assessed with dynamic CT with Patlak plotting [CT-Pp]) for measuring glomerular filtration rates (GFR) in healthy cats.
ANIMALS
7 healthy, laboratory-raised cats.
PROCEDURES
Each method for measuring GFR was performed twice in 7 cats at 24-day intervals. The Wilcoxon signed-rank sum test was used to compare the results obtained from the 14 studies for each method. Results from the 4 methods were assessed for agreement and correlation.
RESULTS
The median GFR values were 2.75, 2.83, 3.14, and 4.26 mL/min/kg, for Tk-GV, CT-Pp, plasma CrCL, and GTS, respectively. Analysis with Wilcoxon signed-rank sum tests identified significant pairwise differences between results obtained with the Tk-GV versus the plasma CrCL method, the Tk-GV versus the GTS method, and the plasma CrCL versus the GTS method. The least variable method was Tk-GV, with an SD of 1.27 (mL/min/kg).
CONCLUSIONS AND CLINICAL RELEVANCE
Findings indicated that Tk-GV yielded GFR measurements comparable with those obtained with CT-Pp, plasma CrCL, and GTS; however, the Tk-GV method yielded the tightest range of results among the methods evaluated.
Abstract
OBJECTIVE To investigate effects of storage conditions on the canine urine protein-to-creatinine ratio (UPC) and on SDS–agarose gel electrophoresis (AGE) of urinary proteins.
SAMPLE Urine specimens from 20 proteinuric (UPC > 0.5) and 20 nonproteinuric (UPC ≤ 0.2) dogs.
PROCEDURES UPC and SDS-AGE were performed on urine specimens stored at room temperature (20°C) and 4°C for up to 5 days and at −20° and −80°C for up to 360 days; some specimens were subjected to 3 freeze-thaw cycles. Results were compared with those obtained for fresh urine specimens.
RESULTS UPC was not affected by storage at room temperature or by freezing. A decrease in UPC was observed for specimens from nonproteinuric dogs after 5 days at 4°C (10%) and from both groups after 90 days at −20° and −80°C (≤ 20% and ≤ 15%, respectively). The SDS-AGE profiles revealed no visual changes regardless of duration of storage for specimens stored at room temperature, 4°C, and −80°C, except for 1 profile after 360 days at −80°C. Repeated freeze-thaw cycles did not affect SDS-AGE profiles. Appearance or strengthening of high-molecular-weight bands that could alter interpretation was evident in SDS-AGE profiles after storage at −20°C for ≥ 15 days (31/40 dogs).
CONCLUSIONS AND CLINICAL RELEVANCE Storage of urine at −20° or −80°C for up to 1 year influenced the UPC without affecting clinical interpretation. Storage of urine specimens at −20°C impaired visual analysis of SDS-AGE. When SDS-AGE cannot be performed on fresh or recently refrigerated urine specimens, storage at −80°C is recommended.
Abstract
OBJECTIVE To determine whether passive ureteral dilation (PUD) would occur after an indwelling ureteral stent was left in place in healthy dogs for 2 or 6 weeks, ureteroscopy would be possible at the time of stent removal, and PUD would be reversible after stent removal.
ANIMALS 5 healthy adult female Beagles.
PROCEDURES A ureteral stent was cystoscopically placed in each ureter of each dog with fluoroscopic guidance (week 0). One stent was removed from 1 ureter in each dog after 2 weeks (ureter group 1), and the other was removed after 6 weeks (ureter group 2); removal timing was randomized. Computed tomographic excretory urography was performed every 2 weeks from weeks 0 through 10 to measure ureteral diameters. Ureteroscopy was attempted at the time of ureteral stent removal in each group. Ureteral diameters were compared among measurement points.
RESULTS The degree of PUD was significant after 2 and 6 weeks of stent placement in both ureter groups. Mean diameter of the midportion of the ureter in both groups prior to stent placement was 1.70 mm (range, 1.3 to 2.7 mm). At stent removal, mean diameter of the midportion of the ureter was 2.86 mm (range, 2.4 to 3.1 mm) in group 1 and 2.80 mm (range, 2.1 to 3.4 mm) in group 2. Ureteroscopy was successfully performed in all dogs up to the renal pelvis. Compared with week 0 values for diameter of the midportion of the ureter, the degree of PUD induced by stent placement had reversed by week 8 in group 1 (mean diameter, 2.00 mm [range, 1.5 to 2.3 mm]).
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that ureteral stent placement for 2 weeks would result in sufficient PUD in healthy dogs to allow ureteroscopy at the time of stent removal and that the original ureteral diameter would eventually be restored. Additional research is needed to determine whether findings would be similar for dogs with urinary tract disease.
Abstract
OBJECTIVE
To determine the effectiveness of manual bladder expression in paraplegic dogs by comparing urine volumes measured by use of intermittent catheterization and ultrasonography.
ANIMALS
36 paraplegic dogs.
PROCEDURES
93 measurements of bladder volume were collected for the 36 dogs. Residual urine volume was determined by use of intermittent urethral catheterization and estimated by use of ultrasonography.
RESULTS
Manual bladder expression voided a mean of 49% of urine from the bladder in this population of dogs. There was no correlation (R 2, 0.06) between the effectiveness of manual bladder expression and body weight. Ultrasonographic estimation of bladder volume had good correlation (R 2, 0.62) with bladder volume determined by use of intermittent bladder catheterization, but clinically unacceptable variation for predicting actual bladder volume (mean difference, 22 mL; 95% confidence interval, −96 to 139 mL).
CONCLUSIONS AND CLINICAL RELEVANCE
Manual bladder expression was ineffective at completely emptying urine from the bladder of paraplegic dogs, but the effectiveness of the procedure was not affected by body weight. Manual bladder expression would likely be a useful procedure to prevent increases in pressure within the bladder. Ultrasonographic estimation of bladder volume could be a useful predictor of actual bladder volume, but it was susceptible to wide variations among dogs, and results should therefore be interpreted with caution.
