Dobermann dogs are reportedly predisposed to familial glomerulonephropathy. Proteinuria is a hallmark of canine familial glomerular diseases. The identification of glomerular abnormalities in breeds so predisposed is of great importance in improving breeding policy. Therefore, markers that allow the detection and localisation of renal damage are needed. The purpose of this study was to investigate the urinary concentrations of immunoglobulin G (uIgG), retinol-binding protein (uRBP), and Tamm–Horsfall protein (uTHP) in a family of Dobermanns with proteinuria and compare these concentrations with the corresponding values in healthy controls.

Twelve Beagles were inoculated with concanavalin A, and after a mean ninefold increase in antibody titer, 1 mg of concanavalin A was infused into each renal artery of each dog to induce in situ immune complex glomerulonephritis. Starting 4 weeks after renal arterial infusion, 6 dogs were treated orally 3 times daily with 30 mg of 3-methyl-2 (3 pyridyl)-1-indoleoctanoic acid (CGS 12970)/kg of body weight, a thromboxane synthetase inhibitor, and 6 dogs (control group) received a gelatin capsule 3 times daily. Endogenous creatinine clearance and 24-hour urinary excretion of protein and thromboxane B2 were determined for each dog prior to renal arterial infusion, at the initiation of treatment and at 2, 4, 6, and 8 weeks after initiation of treatment. In addition, methyoxy-(3)H inulin clearance was determined at initiation of treatment and 4 and 8 weeks later. Renal specimens were examined histologically at the initiation of treatment and 4 and 8 weeks later. Glomerular mononuclear profiles/micrometers(3) were determined from at least 10 equatorially sectioned glomeruli from each dog. Paired t tests were used to compare mean values at the various time points to the respective mean baseline value and 2-sample t tests were used to evaluate differences between treatment groups. At the start of treatment (4 weeks after renal arterial infusion of concanavalin A), histologic evaluation of renal specimens revealed glomerular epithelial crescent formation, mononuclear cell proliferation, and infiltration of neutrophils. Mononuclear cell profiles and urinary excretion of protein and thromboxane B2 were significantly increased, but endogenous creatinine clearance values were unchanged. Treatment with CGS 12970 did not affect endogenous creatinine clearance, methyoxy-(3)H inulin clearance, or glomeruli, however, CGS 12970 treatment significantly decreased urinary excretion of protein and thromboxane B2 when compared with values in the control group. These findings suggested that thromboxane has a role in the pathogenesis of established glomerulonephritis and that thromboxane synthetase inhibition treatment may be beneficial in dogs with established glomerulonephritis.

OBJECTIVE To evaluate effects of blood contamination on dipstick results, specific gravity (SG), and urine protein-to-urine creatinine ratio (UPCR) for urine samples from dogs and cats. SAMPLE Urine samples collected from 279 dogs and 120 cats. PROCEDURES Urine pools were made for each species (dogs [n = 60] and cats [30]). Blood was added to an aliquot of a pool, and serial dilutions were prepared with the remaining urine. Color and dipstick variables were recorded, and SG and UPCR were measured. For cats, 1 set of pools was used; for dogs, 2 sets were used. Comparisons were made between undiluted urine and spiked urine samples for individual colors. Repeated-measures ANOVA on ranks was used to compare dipstick scores and UPCR results; χ2 tests were used to compare proteinuria categorizations (nonproteinuric, borderline, or proteinuric). RESULTS Any blood in the urine resulted in significantly increased dipstick scores for blood. In both species, scores for bilirubin and ketones, pH, and SG were affected by visible blood contamination. No significant difference for the dipstick protein reagent results was evident until a sample was visibly hematuric. The UPCR was significantly increased in dark yellow samples of both species. Proteinuria categorizations differed significantly between undiluted urine and urine of all colors, except light yellow. CONCLUSIONS AND CLINICAL RELEVANCE Any degree of blood contamination affected results of dipstick analysis. Effects depended on urine color and the variable measured. Microscopic blood contamination may affect the UPCR; thus, blood contamination may be a differential diagnosis for proteinuria in yellow urine samples.

OBJECTIVE To assess the urinary protein-to-creatinine ratio (UPCR) of healthy sexually intact male dogs and to compare the UPCR of these dogs before and after castration. ANIMALS 19 client- or shelter-owned healthy adult sexually intact male dogs. PROCEDURES Physical, hematologic, and biochemical examinations and urinalysis (including calculation of the UPCR) were performed on each dog. Dogs were then castrated, and physical examination and urinalysis (including calculation of the UPCR) were performed again at least 15 days after castration. RESULTS A dipstick test yielded positive results for protein in the urine of 10 sexually intact male dogs, but the UPCR was < 0.5 for all sexually intact male dogs. Mean UPCR for sexually intact male dogs was 0.12 (range, 0.10 to 0.32). The UPCR was < 0.2 for all castrated dogs, except for 1. Mean UPCR for all castrated dogs was 0.08 (range, 0.05 to 0.69). There was a significant difference between mean UPCR before and after castration. CONCLUSIONS AND CLINICAL RELEVANCE In this study, pathological proteinuria was not detected in sexually intact male dogs. Positive results for a urine dipstick test should be interpreted with caution in sexually intact male dogs and should be confirmed by assessment of the UPCR. An increased UPCR in sexually intact male dogs may be considered abnormal.

Objective: To determine reference ranges for serum cobalamin (Cbl), urine methylmalonic acid (uMMA), and plasma total homocysteine (tHcys) concentrations and to compare values for healthy control dogs with values for Border Collies (BCs), a breed in which hereditary cobalamin deficiency has been identified. Animals: 113 BCs, 35 healthy control dogs fed a typical diet, and 12 healthy dogs fed a bone and raw food diet exclusively. Procedures: Urine and blood samples were obtained from each dog and Cbl, uMMA, and tHcys concentrations were determined. Results: Reference ranges for Cbl (261 to 1,001 ng/L), uMMA (0 to 4.2 mmol/mol of creatinine), and tHcys (4.3 to 18.4 μmol/L) concentrations were determined. Four BCs had a Cbl concentration lower than the assay detection limit (150 ng/L); median uMMA and tHcys concentrations in these dogs were 4,064 mmol/mol of creatinine and 51.5 μmol/L, respectively. Clinical abnormalities included stunted growth, lethargy, anemia, and proteinuria. Abnormalities improved after administration of cobalamin. Of the 109 healthy BCs with Cbl and tHcys concentrations within reference ranges, 41 (37.6%) had a high uMMA concentration (range, 5 to 360 mmol/mol). Results for dogs fed raw food were similar to those for control dogs. Conclusions and Clinical Relevance: Hereditary cobalamin deficiency is a rare disease with various clinical signs. The finding of methylmalonic aciduria in healthy eucobalaminemic BCs and BCs with clinical signs of Cbl deficiency was surprising and indicated these dogs may have defects in intracellular processing of Cbl or intestinal Cbl malabsorption, respectively. Studies investigating Cbl absorption and metabolic pathways are warranted.

Objective: To determine whether preanalytic and analytic factors affect evaluation of the urinary protein-to-creatinine (UPC) ratio in dogs. Sample: 50 canine urine samples. Procedures: The UPC ratio was measured to assess the intra-assay imprecision (20 measurements within a single session), the influence of predilution (1:10, 1:20, and 1:100) for urine creatinine concentration measurement, and the effect of storage at room temperature (approx 20°C), 4°C, and −20°C. Results: The coefficient of variation at room temperature determined with the 1:20 predilution was < 10.0%, with the highest coefficients of variation found in samples with a low protein concentration or low urine specific gravity. This variability could result in misclassification of samples with UPC ratios close to the thresholds defined by the International Renal Interest Society to classify dogs as nonproteinuric (0.2), borderline proteinuric (0.21 to 0.50), or proteinuric (> 0.51). A proportional bias was found in samples prediluted 1:10, compared with samples prediluted 1:20 or 1:100. At room temperature, the UPC ratio did not significantly increase after 2 and 4 hours. After 12 hours at room temperature and at 4°C, the UPC ratio significantly increased. The UPC ratio did not significantly change during 3 months of storage at −20°C. Conclusions and Clinical Relevance: The intra-assay precision of the UPC ratio was sufficiently low to avoid misclassification of samples, except for values close to 0.2 or 0.5. The optimal predilution ratio for urine creatinine concentration measurement was 1:20. A 1:100 predilution is recommended in samples with a urine specific gravity > 1.030. The UPC ratio must be measured as soon as samples are collected. Alternatively, samples should be immediately frozen to increase their stability and minimize the risk of misclassification of proteinuria.

A 1-year and 6-month-old, intact male, Shit-tzu dog was referred to the Konkuk University Veterinary Teaching Hospital, due to ascite, melena, severe anemia, and polyuria/polydipsia. Complete blood count showed moderate leukocytosis, lymphocytosis, monocytosis, and microcytic hypochromic nonregenerative anemia. On serum biochemistry profiles, hypoalbuminema and hypoproteinemia were observed, and proteinuria was detected on urinalysis.

Six male Beagles were inoculated with Ehrlichia canis. Transient proteinuria was confirmed during the acute phase of infection by serial determination of urinary protein-to-creatinine ratio. Peak urine protein loss, consisting principally of albumin, was observed 2.5 to 3.5 weeks after inoculation. Renal biopsy specimens were obtained before inoculation, during peak proteinuria, and 10 weeks after inoculation when proteinuria had resolved. Renal tissue was evaluated by use of light, immunofluorescent, and electron microscopy to correlate specific glomerular lesions with development of proteinuria. Histologic examination revealed perivenular and interstitial infiltrates of lymphocytes and plasma cells localized principally to the renal cortex. Glomerular lesions were minimal to absent. Immunofluorescent staining revealed moderate to marked deposition of anti-canine IgG and IgM in the glomerular tufts and mesangium. Depositions of anti-canine complement factor C3 were not observed. Immunofluorescent staining persisted 10 weeks after inoculation, despite resolution of proteinuria, and probably represented passive trapping of immunoglobulins. Ultrastructural examination revealed fusion of podocyte processes that coincided with development of proteinuria. Electron-dense deposits or changes in the basement membrane were not observed. Morphometric measurements of average podocyte process length and percentage of coverage of basement membrane by podocyte processes were used to quantify the degree of process fusion. Both measurements increased significantly (P < 0.05) during peak proteinuria, and returned to preinoculation values when proteinuria had resolved 10 weeks after E canis inoculation. These findings indicated possible minimal-change glomerulopathy, rather than immune-complex glomerulonephritis, during acute E canis infection and could explain transient proteinuria without histologic evidence of glomerular disease.

Effects of a protein meal (2.7 g of casein/kg of body weight) on glomerular filtration rate (GFR) and renal plasma flow (RPF) were assessed in dogs after 15/16 nephrectomy (n = 10), and were compared with observations in dogs with intact kidneys (n = 5). Increase in GFR and RPF was observed in both groups of dogs between 1.5 and 8 hours after protein ingestion. A maximal value for GFR was observed between 4 and 5 hours after protein ingestion in dogs of both groups. Enhancement of urinary protein excretion was evident in partially nephrectomized dogs after protein ingestion (P < 0.05), a result that was confirmed by 24-hour total urine collection from partially nephrectomized dogs fed a balanced ration. A qualitatively similar vasodilatory response was observed in partially nephrectomized dogs and in dogs with intact kidneys, and the mean maximal increase of GFR and RPF expressed as a percentage of baseline values in the latter dogs (47.0 +/- 8.1 and 43.6 +/- 10.3%, respectively) exceeded that observed in partially nephrectomized dogs (20.8 +/- 2.2 and 22.7 +/- 6.3%, respectively; P < 0.01). The incremental response of the kidneys to protein ingestion was directly related to the degree of renal function, as reflected in the linear regression relationship between the incremental increase in GFR and the baseline value for GFR (P < 0.01, R2 = 0.721).

To evaluate renal function and obtain reference values for measurements of urinary excretion of various substances, quantitative urinalysis was performed in healthy, growing kittens from 4 to 30 weeks after birth. Endogenous creatinine clearance, 24-hour urine protein excretion, and urine protein-to-creatinine ratio were determined. Additionally, fractional excretion to creatinine clearance was calculated for calcium, inorganic phosphorus, sodium, potassium, and chloride. Mean +/- SD endogenous creatinine clearance values (range, 3.80 +/- 0.48 to 4.74 +/- 0.61 ml/min/kg) were significantly (P < 0.0001) higher in kittens 9 to 19 weeks old, compared with younger (range, 1.39 +/- 0.85 to 3.59 +/- 0.86 ml/min/kg) and older kittens (range, 2.69 +/- 0.40 to 3.46 +/- 0.37 ml/min/kg). Mean values for all kittens for 24-hour urine protein excretion (range, 2.54 +/- 1.81 mg/kg at 4 weeks to 11.39 +/- 7.61 mg/kg at 14 weeks) and for urine protein-to-creatinine ratio (range, 0.14 +/- 0.03 to 0.34 +/- 0.18) varied from week to week of age. The urine protein-to-creatinine ratio in kittens greater than or equal to 9 weeks old correlated well (R2 = 0.861) with 24-hour urine protein excretion. Urinary fractional excretion of calcium, inorganic phosphorus, sodium, potassium, and chloride in kittens varied among age groups, being significantly (P < 0.01) different for potassium and calcium in young kittens (4 to 6 weeks) and older kittens (greater than or equal to 7 weeks).