Objective—To compare estimation of glomerular filtration rate determined via conventional methods (ie, scintigraphy and plasma clearance of technetium Tc 99m pentetate) and dynamic single-slice computed tomography (CT).
Animals—8 healthy adult cats.
Procedures—Scintigraphy, plasma clearance testing, and dynamic CT were performed on each cat on the same day; order of examinations was randomized. Separate observers performed GFR calculations for scintigraphy, plasma clearance testing, or dynamic CT. Methods were compared via Bland-Altman plots and considered interchangeable and acceptable when the 95% limits of agreement (mean difference between methods ± 1.96 SD of the differences) were ≤ 0.7 mL/min/kg.
Results—Global GFR differed < 0.7 mL/min/kg in 5 of 8 cats when comparing plasma clearance testing and dynamic CT; the limits of agreement were 1.4 and −1.7 mL/min/kg. The mean ± SD difference was −0.2 ± 0.8 mL/min/kg, and the maximum difference was 1.6 mL/min/kg. The mean ± SD difference (absolute value) for percentage filtration by individual kidneys was 2.4 ± 10.5% when comparing scintigraphy and dynamic CT; the maximum difference was 20%, and the limits of agreement were 18% and 23% (absolute value).
Conclusions and Clinical Relevance—GFR estimation via dynamic CT exceeded the definition for acceptable clinical use, compared with results for conventional methods, which was likely attributable to sample size and preventable technical complications. Because 5 of 8 cats had comparable values between methods, further investigation of dynamic CT in a larger sample population with a wide range of GFR values should be performed.
Objectives—To determine effects of commonly used diuretic treatments on glomerular filtration rate (GFR), renal blood flow (RBF), and urine output (UO) and compare 2 methods of GFR measurement in healthy awake cats.
Animals—8 healthy cats.
Procedure—In a randomized crossover design, cats were randomly allocated to 4 groups: control; IV administration of fluids; IV administration of fluids and mannitol; and IV administration of fluids, dopamine, and furosemide. Inulin and para-aminohippuric acid were used for determination of plasma clearance for GFR and RBF, respectively. Plasma clearance of technetium-Tc-99m-diethylenetriaminepentacetic acid (99mTc-DTPA) was also used for GFR determination.
Results—Furosemide-dopamine induced the largest UO, compared with other groups. Both mannitol and fluid therapy increased RBF, compared with the control group. Mannitol, and not fluid therapy, increased RBF, compared with furosemide-dopamine. There were significant differences in GFR values calculated from 99mTc-DTPA and inulin clearances between the 2 groups. In all groups, use of 99mTc-DTPA caused underestimation of GFR, compared with use of inulin.
Conclusions and Clinical Relevance—In healthy awake cats, administration of furosemide-dopamine did not increase GFR or RBF despite increased UO. Fluid therapy and fluid therapy plus mannitol improved RBF. Determination of GFR by use of 99mTc-DTPA cannot always be substituted for inulin clearance when accurate measurement is required.
Objective—To evaluate factors associated with response to treatment, remission duration, and survival in cats with low-grade lymphoma affecting various organ systems.
Design—Retrospective case series.
Sample Population—41 cats with histologically confirmed low-grade lymphocytic lymphoma.
Procedures—Medical records and biopsy specimens of cats with histologically confirmed low-grade lymphocytic lymphoma of various organ systems treated with prednisone and chlorambucil between 1995 and 2005 were reviewed. The Kaplan-Meier method was used to estimate remission duration and survival. Factors potentially associated with prognosis were compared.
Results—Common clinical signs were weight loss (83%), vomiting (73%), anorexia (66%), and diarrhea (58%). Seventy-eight percent of cats tested had low serum cobalamin concentrations. Lymphoma was confined to the gastrointestinal tract in 68% of cats. Fifty-six percent of cats achieved a complete response to treatment, and 39% achieved a partial response. Five percent of cats had no response. No association was found between any risk factors (including anatomic site) and response to treatment. Partial response was associated with shorter remission duration, compared with complete response; median remission duration was 428 days for cats achieving a partial response, compared with 897 days for cats achieving a complete response. No other factors were associated with remission duration. Overall median survival time was 704 days. No factors were significantly associated with survival time.
Conclusions and Clinical Relevance—Most cats with lymphocytic lymphoma responded to treatment with prednisone and chlorambucil, and most factors evaluated were not associated with outcome.
Objective—To determine whether severity of periodontal disease (PD) was associated with systemic health indices in dogs and whether treatment of PD altered systemic health indices.
Design—Prospective cohort study.
Procedures—Healthy dogs with clinical signs of PD were included in the study. Physical examination, serum biochemical analysis, a CBC, urine evaluati on, measurement of serum C-reactive protein (CRP) concentration, and a microalbuminuria test were performed prior to treatment of PD. All tooth roots were scored for gingivitis and attachment loss, and appropriate treatment of PD was performed. Laboratory data were obtained 4 weeks after treatment. The Spearman rank correlation and Wilcoxon signed rank test were used for statistical analysis.
Results—Analyses of the correlation of several variables with attachment loss or gingivitis or of differences before and after treatment revealed significant results for several variables. After applying Bonferroni corrections for family-wise error rate, significant rank correlations were found between attachment loss and platelet number (r = 0.54), creatinine concentration (r = −0.49), and the within-dog difference in CRP concentrations before and after treatment (r = 0.40). The BUN concentration was significantly higher after treatment than before treatment.
Conclusions and Clinical Relevance—Increasing severity of attachment loss was associated with changes in systemic inflammatory variables and renal indices. A decrease in CRP concentration after treatment was correlated with the severity of PD. The BUN concentration increased significantly after treatment of PD. There is a need for continued research into the systemic impact of PD.
Objective—To document clinicopathologic, histologic, and toxicologic findings in cats inadvertently exposed to pet food contaminated with melamine and cyanuric acid.
Animals—70 cats from a single cattery inadvertently fed contaminated food that was the subject of a March 2007 recall.
Procedures—Clinical signs, clinicopathologic and histopathologic findings, and results of toxicologic analyses were recorded
Results—Clinical signs were identified in 43 cats and included inappetence, vomiting, polyuria, polydipsia, and lethargy. Azotemia was documented in 38 of the 68 cats for which serum biochemical analyses were performed 7 to 11 days after consumption of the contaminated food. One cat died, and 13 were euthanized. Histologic examination of kidney specimens from 13 cats revealed intratubular crystalluria, tubular necrosis with regeneration, and subcapsular perivascular inflammation characterized by perivascular fibroplasia or fibrosis and inflammation with intravascular fibrin thrombi. Toxicologic analyses revealed melamine and cyanuric acid in samples of cat food, vomitus, urine, and kidneys.
Conclusions and Clinical Relevance—In cats unintentionally fed pet food contaminated with melamine and cyanuric acid, the most consistent clinical and pathologic abnormalities were associated with the urinary tract, specifically tubular necrosis and crystalluria.