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Abstract

Objective—To evaluate the use of multifrequency bioelectrical impedance analysis (MF-BIA) for estimating total body water (TBW), extracellular fluid volume (ECFV), and intracellular fluid volume (ICFV) in horses.

Animals—9 healthy mares.

Procedure—TBW and ECFV were measured by use of deuterium oxide and sodium bromide dilution techniques, respectively. Intracellular fluid volume was calculated as the difference between TBW and ECFV. Concurrently, MF-BIA recordings were obtained by use of 4 anatomic electrode positions and 3 measurements of length. Models for MF-BIA data were created for all combinations of length and anatomic electrode position. Models were evaluated to determine the position-length configuration that provided the most consistent estimates of TBW, ECFV, and ICFV, compared with values determined by use of the dilution techniques.

Results—Positioning electrodes over the ipsilateral carpus and tarsus and use of height at the tuber sacrale for length provided the closest estimate between values for TBW, ECFV, and ICFV predicted by use of MF-BIA and measured values obtained by dilutional techniques. This model had the narrowest 95% limits of agreement.

Conclusions and Clinical Relevance—MF-BIA techniques have been used to predict changes in TBW, ECFV, and ICFV in healthy and diseased humans. Results reported in this study provide an equine-specific model to serve as the basis for further evaluation of MF-BIA in horses with altered fluid states. The MF-BIA techniques have a number of potential applications for use in horses, including evaluation of exercise physiology, pharmacologic studies, and critical-care management. ( Am J Vet Res 2004;65:320–326)

Full access
in American Journal of Veterinary Research

Abstract

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.

Full access
in American Journal of Veterinary Research

SUMMARY

Objective

To determine usefulness of carbamylated hemoglobin (CarHb) concentration for differentiation of acute renal failure (ARF) from chronic renal failure (CRF) in dogs.

Sample Population

Samples from dogs with ARF or CRF and from nonazotemic control dogs.

Procedure

CarHb concentration was determined in heparinized blood samples by measuring the micrograms of valine hydantoin (VH) per gram of hemoglobin (Hb), using a high-performance liquid chromatography assay, in which carbamyl valine is converted to VH via acid hydrolysis.

Results

CarHb concentration was significantly higher in dogs with ARF and CRF, compared with values in control dogs (ARF vs control, P < 0.05; CRF vs control, P < 0.001). Furthermore, CarHb concentration was significantly (P < 0.001) higher in dogs with CRF, compared with that in dogs with ARF. Carbamylated hemoglobin concentration did not correlate with serum urea nitrogen or creatinine concentration. Using a cutoff value of 100 μg of VH/g of Hb, the sensitivity and specificity of CarHb concentration for differentiating ARF from CRF was 96.1 and 84.2%, respectively.

Conclusions

CarHb concentration was useful in the differentiation of ARF from CRF in the dogs of this study.

Clinical Relevance

CarHb concentration may be used to increase the accuracy of identifying ARF, so that early, aggressive management can be instituted, thereby increasing the chance of recovery. (Am J Vet Res 1997;58:1193–1196)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To characterize potential changes in preprandial plasma amino acid concentrations in cats with naturally acquired chronic renal failure (CRF), compared with healthy cats, and to assess potential effects of the severity of renal failure on plasma amino acid concentrations in these cats.

Animals

62 adult cats.

Procedure

Preprandial plasma amino acid concentrations were evaluated in 38 cats with mild, moderate, or severe CRF and in 24 apparently healthy cats. Effects of severity of renal failure, amount of dietary protein, degree of weight loss, appetite, and body condition on plasma amino acid profiles were evaluated.

Results

Cats with various stages of CRF had significantly (P < 0.05) decreased plasma concentrations of o-hydroxyproline, glutamate, proline, glycine, alanine, tyrosine, tryptophan, and arginine, and significantly increased plasma concentrations of asparagine, citrulline, ornithine, 1-methylhistidine, and 3-methylhistidine. Significant (P < 0.05) alterations in amino acid concentrations also were identified when cats with CRF were grouped by appetite or severity of renal disease. Amount of dietary protein, body condition, or degree of weight loss had no significant effect on plasma amino acid concentrations.

Conclusions

Compared with those in healthy cats, preprandial plasma amino acid profiles in cats with mild, moderate, or severe CRF are abnormal.

Clinical Relevance

Despite frequency of altered plasma amino acid concentrations in cats with CRF, the magnitude of these changes is mild and of little clinical relevance. Short-term use of a commercial protein-restricted diet has no deleterious effects on plasma amino acid concentrations. (Am J Vet Res 1999;60:109–113)

Free access
in American Journal of Veterinary Research

Objective

To test efficacy and safety of recombinant human erythropoietin (r-HuEPO) administration in dogs and cats with naturally developing chronic renal failure.

Design

Case series.

Animals

6 client-owned dogs and 11 client-owned cats with chronic renal failure.

Procedures

r-HuEPO was administered intravenously or subcutaneously. Erythropoietic effects were monitored by determining CBC, performing cytologic examination of bone marrow aspirates, and measuring serum iron concentration before and during treatment. Development of adverse effects was monitored by performing sequential clinical assessments, CBC, and serum biochemical tests and by measuring indirect blood pressure and anti-r-HuEPO antibody titers.

Results

Administration of r-HuEPO increased RBC and reticulocyte counts, hemoglobin concentration, and Hct comparably in dogs and cats. Assessments of clinical well-being, including appetite, energy, weight gain, alertness, strength, and playfulness, were improved variably. Adverse effects, including anemia, anti-r-HuEPO antibody production, seizures, systemic hypertension, and iron deficiency, were demonstrated inconsistently in dogs and cats.

Clinical Implications

Anemia contributes to clinical manifestations of chronic renal failure in dogs and cats. Administration of r-HuEPO has the potential to resolve anemia and improve clinical well-being. However, its administration poses risks of antibody production and adverse effects associated with correction of RBC mass. Use of r-HuEPO in dogs and cats requires conscientious assessment of risks and benefits until homologous forms of erythropoietin are available. (J Am Vet Med Assoc 1998; 212:521-528)

Free access
in Journal of the American Veterinary Medical Association

Objective—

To determine prevalence and severity of systemic arterial hypertension and proteinuria in dogs with naturally developing hyperadrenocorticism and to determine whether these abnormalities resolve with adequate management of the disease.

Design—

Case series and cohort study.

Animals—

77 dogs with naturally developing hyperadrenocorticism examined once; 15 dogs examined before and after treatment.

Results—

Among dogs examined only once, hypertension was diagnosed in 21 of 26 dogs with untreated pituitary-dependent hyperadrenocorticism (PDH), 17 of 21 with inadequately controlled PDH, 8 of 16 with well-controlled PDH, 10 of 10 with an untreated adrenocortical tumor, and 0 of 4 that had undergone adrenalectomy because of an adrenocortical tumor. Untreated dogs and dogs with inadequately controlled PDH had significantly higher blood pressures than did other dogs. Proteinuria was documented in 12 of 26 dogs with untreated PDH, 5 of 16 with inadequately controlled PDH, 3 of 14 with well-controlled PDH, 5 of 8 with an untreated adrenocortical tumor, and 1 of 3 that had undergone adrenalectomy. Dogs with untreated PDH and dogs with an untreated adrenocortical tumor had higher urine protein/creatinine ratios than did dogs with well-controlled PDH. Among dogs evaluated before and after treatment, blood pressure and urine protein/creatinine ratio did not change in 8 dogs with inadequately controlled hyperadrenocorticism, but decreased in 7 dogs with well-controlled disease.

Clinical Implications—

Results suggest that systemic hypertension and proteinuria are common in dogs with untreated hyperadrenocorticism and that successful treatment of hyperadrenocorticism will result in resolution of these abnormalities in many, but not all, dogs. (J Am Vet Med Assoc 1996;209:1724–1729)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine sensitivity and specificity of radiography, ultrasonography, and antegrade pyelography for detection of ureteral obstructions in cats.

Design—Retrospective study.

Animals—11 cats.

Procedure—Medical records of cats that had radiography, ultrasonography, and antegrade pyelography performed for suspected ureteral obstructions were examined. Ultrasound-guided pyelocentesis and fluoroscopic- assisted antegrade pyelography were performed on 18 kidneys in 11 cats. Obstructive ureteral lesions were confirmed in all cats by surgical or necropsy examination. Sensitivity and specificity of survey radiography, ultrasonography, and antegrade pyelography for identification of ureteral obstructions were calculated. Surgical or necropsy findings were used as the standard for comparison.

Results—All cats were azotemic. Mean ± SD serum creatinine and BUN concentrations were 10.2 ± 6.1 and 149 ± 82 mg/dL, respectively. Fifteen of 18 ureters were found to be obstructed at surgery or necropsy. Sensitivity and specificity were 60 and 100% for radiography and 100 and 33% for ultrasonography, respectively, in identification of ureteral obstructions. Leakage of contrast material developed in 8 of 18 kidneys during antegrade pyelography and prevented diagnostic interpretation in 5 of 18 studies. For the 13 diagnostic studies, specificity and sensitivity were 100% by use of the antegrade pyelography technique. Correct identification of the anatomic location of the ureteral obstruction was obtained in 100% of diagnostic antegrade pyelography studies and in 60% of radiography or ultrasonography studies.

Conclusions and Clinical Relevance—Antegrade pyelography can be a useful alternative in the diagnosis and localization of ureteral obstructions in azotemic cats, although leakage of contrast material may prevent interpretation of the study. (J Am Vet Med Assoc 2003;222:1576–1581)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine clinical, clinicopathologic, radiographic, and ultrasonographic abnormalities in cats with ureteral calculi.

Design—Retrospective study.

Animals—163 client-owned cats.

Procedure—Medical records were reviewed, and information on signalment, history, clinical signs, and results of clinicopathologic testing and diagnostic imaging was obtained.

Results—The number of cats in which ureterolithiasis was diagnosed each year increased progressively during the study period. Clinical signs tended to be nonspecific and included inappetence, vomiting, lethargy, and weight loss. A combination of survey radiography and abdominal ultrasonography revealed ureteral calculi in 66 of 73 (90%) cats in which the diagnosis was confirmed at surgery or necropsy. Ultrasonography revealed that ureteral calculi were causing ureteral obstruction in 143 of 155 (92%) cats. One hundred thirty-four of 162 (83%) cats had azotemia, 84 of 156 (54%) had hyperphosphatemia, and 22 of 152 (14%) had hypercalcemia. Urinary tract infection was documented in 10 of 119 (8%). Fifty-eight of 76 (76%) cats with unilateral ureterolithiasis had azotemia and 33 (43%) had hyperphosphatemia, indicating impairment of renal function in the contralateral kidney or prerenal azotemia. Ultrasonographic imaging of the contralateral kidney in cats with unilateral ureteral calculi suggested that preexisting renal parenchymal disease was common in cats with ureterolithiasis. Ninety-one of 93 (98%) ureteral calculi contained calcium oxalate.

Conclusions and Clinical Relevance—Results suggest that abdominal imaging should be performed in all cats with chronic nonspecific signs or with acute or chronic renal failure to rule out ureterolithiasis. Preexisting renal disease may be common in cats with ureteral calculi. (J Am Vet Med Assoc 2005;226: 932–936)

Full access
in Journal of the American Veterinary Medical Association