Effects of long-term administration of enalapril on clinical indicators of renal function in dogs with compensated mitral regurgitation

OBJECTIVE: To determine the effect of long-term administration of enalapril on renal function in dogs with severe, compensated mitral regurgitation. DESIGN: Randomized controlled trial. ANIMALS: 139 dogs with mitral regurgitation but without overt signs of heart failure. PROCEDURE: Dogs were randomly assigned to be treated with enalapril (0.5 mg/kg [0.23 mg/lb], PO, q 24 h) or placebo, and serum creatinine and urea nitrogen concentrations were measured at regular intervals for up to 26 months. RESULTS: Adequate information on renal function was obtained from 132 dogs; follow-up time ranged from 0.5 to 26 months (median, 12 months). Mean serum creatinine and urea nitrogen concentrations were not significantly different between dogs receiving enalapril and dogs receiving the placebo at any time, nor were concentrations significantly different from baseline concentrations. Proportions of dogs that developed azotemia or that had a +/- 35% increase in serum creatinine or urea nitrogen concentration were also not significantly different between groups. Conclusions: And Clinical Relevance: Results suggest that administration of enalapril for up to 2 years did not have any demonstrable adverse effects on renal function in dogs with severe, compensated mitral regurgitation.     

Clinical evaluation of glomerular function: 24-hour creatinine clearance in dogs.

Methods of renal clearance to measure glomerular filtration rate (GFR) were compared with plasma creatinine concentration in clinically normal and partially nephrectomized dogs. Glomerular filtration rate was measured by use of a simple 24-hour creatinine clearance method in 36 normal female Beagles. Mean values were 57.6 +/- 9.3 ml/minute/m2 of body surface or 3.7 +/- 0.77 ml/minute/kg of body weight. Variability of this measurement was considerable, as determined in 4 dogs studied on 4 consecutive days. Glomerular filtration rate was measured in the same 36 dogs while they were under anesthesia, using short clearance periods to compare inulin and endogenous creatinine clearance. Mean values for inulin were 41.8 +/- 13.9 ml/minute/m2 of body surface. A close agreement with creatinine clearance was found (correlation coefficient, 0.998). Mean plasma creatinine concentration was 0.82 (range, 0.5--1.0) mg/100 ml. The value of GFR measurement compared with plasma creatinine concentration was determined in 10 dogs after 75% nephrectomy. Sixty days after partial nephrectomy, GFR was reduced to 61% of normal. Mean plasma creatinine and blood urea nitrogen were 1.2 +/- 0.14 mg/100 ml and 20.4 +/- 7.1 mg/100 ml, respectively. Thus, the detection of reduced renal function may be uncertain when plasma creatinine or blood urea nitrogen are used as a means of evaluating renal function. It was concluded that a simple method of creatinine clearance is a sensitive and useful measurement to detect early or borderline reduction in glomerular function.     

Use of 99mTc diethylenetriaminepentaacetic acid for assessment of renal function in dogs with suspected renal disease

The effectiveness of technetium 99m-labeled diethylenetriaminepentaacetic acid (99mTc DTPA) to assess renal function in 13 dogs with suspected renal disease was evaluated. Glomerular filtration rates (actual GFR) were determined on the basis of endogenous creatinine clearance. Predicted GFR were determined by using 99mTc DTPA within 72 hours after the determination of creatinine clearance. The percentage of an IV administered dose of 99mTc DTPA in the kidneys (percentage dose) was determined. Two equations were used to calculate predicted GFR, which were derived from previously reported linear regression analysis of inulin (In) and creatinine (Cr) GFR vs percentage dose 99mTc DTPA in dog kidneys. The correlations of actual GFR vs predicted GFR (In) and actual GFR vs predicted GFR (Cr) were both r = 0.92. The dogs' mean actual GFR was 1.73 +/- 1.35 ml/min/kg. Their mean predicted GFR (In) and predicted GFR (Cr) were 1.92 +/- 1.42 ml/min/kg and 1.85 +/- 1.27 ml/min/kg, respectively. Therefore, 99mTc DTPA can be used with high accuracy as an agent to predict GFR in dogs with suspected renal disease. The procedure for determining GFR by use of nuclear medicine was rapid and noninvasive and appeared to induce little stress in the animals evaluated.     

Plasma disappearance of creatinine as a renal function test in the dog

The serum concentration of creatinine at 120 minutes (SC120) after intravenous injection of 88 mg kg-1 of creatinine, the plasma half-life (t1/2) and the plasma clearance of creatinine (PCC) were evaluated as renal function tests in 30 healthy adult dogs and six adult dogs with known or suspected renal disease. The mean SC120 in the normal dog was 0.31 +/- 0.08 mmol litre-1 and in the clinical cases 0.71 +/- 0.19 mmol litre-1. The correlation coefficients between SC120 and renal creatinine clearance (RCC) for the normal dogs and the clinical cases were -0.76 and -0.69, respectively. At 120 minutes after injection, 95 per cent of normal dogs would be predicted to have a serum creatinine concentration below 0.46 mmol litre-1. The mean plasma t1/2 of creatinine for the normal dogs was 107.7 +/- 17.96 minutes, while the clinical cases had a wide range of values (148.8 to 620.1 minutes). Plasma t1/2 of creatinine was correlated with RCC for both the normal dogs and the clinical cases (r = -0.55, r = -0.91, respectively). The mean PCC for the normal dogs was 7.42 +/- 2.22 ml min-1 kg-1 (range 4.95 to 13.28 ml min-1 kg-1). There was a good correlation between RCC and PCC (r = 0.7). The PCC for the clinical cases ranged from 0.76 to 3.37 ml min-1 kg-1. The correlation between RCC and PCC was significant (r = 0.91). Thus SC120, t1/2 and PCC may be useful methods of assessing renal function in dogs with renal impairment insufficient to cause azotaemia.     

Cisplatin Therapy in 41 Dogs With Malignant Tumors

Forty-one dogs with a variety of histopathologically diagnosed, measurable tumors were treated with cisplatin (cis-diamminedichloroplatinum, Platinol, Bristol Laboratories, Syracuse, NY 13221-4755) as a single agent at a dosage of 60 mg/m2 given intravenously at 3-week intervals. In an attempt to avoid renal toxicity of cisplatin, saline diuresis was induced and maintained for 4 hours before and 2 hours following cisplatin administration. The dogs received one to ten doses of cisplatin. To determine response to therapy and to monitor toxicity of the drug, the dogs were evaluated with physical examinations including tumor measurements, radiography, complete blood counts, platelet counts, urinalyses, serum urea nitrogen concentrations, and serum creatinine concentrations. An overall response rate of 19% was observed. Complete remission occurred in one of 11 dogs with squamous cell carcinomas and one of one dog with a mediastinal undifferentiated carcinoma. Partial remissions were documented in one of 11 dogs with squamous cell carcinomas, two of three dogs with metastatic osteosarcomas, one of three dogs with nasal adenocarcinomas, and one of one dog with a thyroid adenocarcinoma. Toxic side effects were primarily gastrointestinal in nature, with vomiting occurring 1-6 hours after cisplatin administration in 27 of 41 dogs. Severe anorexia occurred in three dogs, and hemorrhagic diarrhea was observed in one dog. One dog developed grand mal seizures and died 3 hours following therapy. Granulocytopenia was documented in six dogs, and thrombocytopenia was observed in four dogs. One dog showed an increase in serum urea nitrogen and creatinine concentrations, but this patient had known pre-existing renal disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of ascorbic acid on BUN, creatinine, resistive index in canine renal ischemia-reperfusion injury

Renal ischemia as a course of renal transplantation is a common cause of renal dysfunction as renal failure. The purpose of this study was to investigate the influence of ascorbic acid on blood urea nitrogen (BUN), creatinine (Cr) and resistive index (RI) for dog models with renal ischemia-reperfusion (I/R) injury. Renal ischemia was induced on 6 Beagle dogs. The left kidney was exposed to normothermic ischemia for a short period at 30 min followed by reperfusion. On the blood Cr level and RI, there was no significant difference comparing both groups. 14 days after I/R injury a significant reduction on the blood BUN level was observed in the vehicle group (34.06 mg/dl) compared to that of ischemia induced treated group (10.3mg/dl) (p < 0.05). In conclusion, administration of ascorbic acid for renal ischemic-reperfusion injury had influence on blood BUN level, but it was not revealed the influence on blood Cr and RI.     

Plasma concentrations of an angiotensin-converting enzyme inhibitor, benazepril, and its active metabolite, benazeprilat, after repeated administrations of benazepril in dogs with experimental kidney impairment

In order to examine the safety of an angiotensin-converting enzyme (ACE) inhibitor in dogs with impaired renal excretion route, benazepril was administered orally, and plasma concentrations of benazeprilat, the active metabolite of benazepril, were determined in dogs with renal mass reduction (1/4th kidney) created by right-side nephrectomy and ligation of branches of the left renal arteries. Five dogs were administered benazepril orally at a given dose (0.5 mg/kg body weight) and 4 other dogs received 20 times that dose (10 mg/kg body weight) once daily for 15 consecutive days before (intact kidney period) and after (1/4th kidney period) creation of kidney impairment. Six control dogs received surgical treatment, but no drug. After creating a 1/4th kidney, plasma urea nitrogen and creatinine concentrations increased to approximately 30 mg/dl and 2.0 mg/dl, respectively, and renal plasma flow and glomerular filtration rate decreased to 37% and 30% of pre-treatment values, respectively. However, these parameters did not change significantly during the 1/4th kidney period both in the 0.5 mg/kg and 10 mg/kg groups. In the 0.5 mg/kg group, plasma benazeprilat concentrations increased to approximately 20 ng/ml to 340 ng/ml 2 hr after each administration, and there were no significant differences between the plasma benazeprilat concentrations during the intact and 1/4th kidney periods. In the 10 mg/kg group, plasma benazeprilat concentrations varied in the individual dog, but did not increase with the days of administration, and were not significantly different on each administration day between the intact and 1/4th kidney periods in either dose group. The AUCs(0-24) of plasma benazeprilat concentrations determined on the 15th administration day were not different between the intact and 1/4th kidney periods in dogs of either dose group. Plasma ACE activities decreased after drug administration in dogs of both groups. Benazepril seemed to have a high safety, and the adjustment of dosage regimen might not be needed in dogs with mild to moderate renal function impairment because the drug was excreted both from the kidneys and liver.     

Renal anemia in polycystic kidney disease mouse.

DBA/2FG-pcy mice developed the chronic renal failure by the progressive polycystic formation at five months old. Their bilaterally enlarged kidneys occupied about 15% of the body weight. It was about 9 times larger than the normal kidney of DBA/2N mice. A large number of various-sized cysts appeared in cortex and medulla of bilateral light-yellow kidneys of sponge-like shape. Blood urea nitrogen and creatinine increased. Red blood cells (746 +/- 39 x 10(4)/mm3), hemoglobin (8.8 +/- 0.4 g/dl) and hematocrits (31.1 +/- 1.5%) were lower than those of normal control mice. Serum erythropoietin level and reticulocytes did not increase. In addition, the treatment with exogenous erythropoietin improved the anemia in DBA/2FG-pcy mice. It was suggested that the anemia in DBA/2FG-pcy mice was due to the disorder of erythropoietin production caused by the progressive polycystic formation in kidneys.     

Evaluation of a one-hour saline diuresis protocol for administration of cisplatin to dogs.

A study was undertaken to determine the toxic effects of cisplatin, an antineoplastic agent, when administered immediately after a 1-hour saline diuresis. Four treatments with cisplatin (70 mg/m2 of body surface, q 3 wk) were administered IV to 6 healthy dogs over a 20-minute period after 0.9% NaCl (saline) solution was administered IV for 1 hour at a volume of 132 ml (kg)0.75. Each dog vomited at least once within 8 hours after each treatment was administered. Clinical status, body weight, and food consumption were normal throughout the 12-week study for 5 of the 6 dogs. The sixth dog developed acute renal failure and became acutely blind and deaf within 3 days after the fourth treatment with cisplatin. Serum electrolyte, creatinine, and urea nitrogen values remained within established normal limits in all dogs immediately prior to each treatment, and in 5 of 6 dogs evaluated 3 weeks after the final treatment. The serum creatinine value (3.3 mg/dl) obtained from the Beagle euthanatized 2 weeks after the fourth treatment was above established normal values. Despite normalcy for all but 1 of the creatinine values, serum creatinine concentration obtained 3 weeks after the final treatment with cisplatin was significantly (P = 0.0001) higher than pretreatment values. When compared with data from all other evaluation periods, significant decreases in glomerular filtration rate, as determined by exogenous (P less than or equal to 0.0001) and endogenous (P less than or equal to 0.0001) creatinine clearance testing, were identified 3 weeks after the fourth treatment with cisplatin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Renal allograft histopathology in dog leukocyte antigen mismatched dogs after renal transplantation

OBJECTIVE: To evaluate allograft histopathology in dog leukocyte antigen (DLA)-mismatched dogs undergoing renal transplantation, with transient immunosuppression. STUDY DESIGN: Prospective study. ANIMALS: Ten healthy adult mongrel dogs. METHODS: Reciprocal renal transplantation and bilateral nephrectomy were performed. Immune conditioning consisted of nonmyeloablative (200 cGy), total body irradiation (TBI), bone marrow transplantation (BMT; 7 dogs), cyclosporine (CSA; 15 mg/kg every 12 hours), mycophenolate mofetil (MMF; 10 mg/kg every 12 hours) and intermittent prednisone (1 mg/kg every 12-24 hours). Biopsies were collected at transplantation, during full immunosuppression (44-90 days), and once medications were reduced or discontinued (228-580 days). Biopsies were evaluated for interstitial, tubular, vascular, and glomerular lesions. Blood urea nitrogen, creatinine, serum CSA concentrations, and clinical score were determined at each biopsy. RESULTS: Seven dogs survived >200 days (mean, 380 days). Transient CSA toxicity was suspected in 6 dogs. Lymphocytic, plasmacytic interstitial inflammation, and tubulitis progressed when immunosuppressive medications were decreased. All 7 dogs had histologic lesions consistent with some degree of allograft rejection at study end. CONCLUSION: Nonmyeloablative TBI, BMT, and short-term immunosuppression with CSA, MMF, and prednisone allowed renal allograft function and dog survival for >200 days. It appears unlikely that total drug withdrawal will be possible in unrelated DLA-mismatched dogs using this protocol. CLINICAL RELEVANCE: Transient immunosuppression with MMF, CSA, and prednisone along with BMT and nonmyeloablative TBI may make kidney transplantation a clinical reality for treatment of kidney failure in dogs. Initiating both MMF and CSA at lower dosages may potentially eliminate early renal allograft injury.     

Complications and outcomes associated with use of gastrostomy tubes for nutritional management of dogs with renal failure: 56 cases (1994-1999)

OBJECTIVE: To evaluate complications and outcomes associated with use of gastrostomy tubes in dogs with renal failure. DESIGN: Retrospective study. ANIMALS:56 dogs. PROCEDURE: Medical records were reviewed for dogs with renal failure that were treated by use of gastrostomy tubes. RESULTS: Mean +/- SD BUN concentration was 134 +/- 79 mg/dl and mean serum creatinine concentration was 9.0 +/- 3.8 mg/dl. Low-profile gastrostomy tubes were used for initial placement in 10 dogs, and traditional gastrostomy tubes were used in 46 dogs. Mild stoma-site complications included discharge, swelling, erythema, and signs of pain in 26 (46%) of dogs. Twenty-six gastrostomy tubes were replaced in 15 dogs; 11 were replaced because of patient removal, 6 were replaced because of tube wear, and 3 were replaced for other reasons. Six tubes were replaced by low-profile gastrostomy tubes. Gastrostomy tubes were used for 65 +/- 91 days (range, 1 to 438 days). Eight dogs gained weight, 11 did not change weight, and 17 lost weight; information was not available for 20 dogs. Three dogs were euthanatized because they removed their gastrostomy tubes, 2 were euthanatized because of evidence of tube migration, and 1 died of peritonitis. CONCLUSIONS AND CLINICAL RELEVANCE: Gastrostomy tubes appear to be safe and effective for improving nutritional status of dogs with renal failure.     

Evaluation of clinical status, renal function, and hematopoietic variables after unilateral nephrectomy in canine kidney donors

OBJECTIVE: To determine clinical status and renal and hematopoietic function after kidney donation and identify risks associated with kidney donation in dogs. DESIGN: Prospective study. ANIMALS: 14 dogs that underwent unilateral nephrectomy for kidney donation. PROCEDURES: Records were reviewed retrospectively to collect data regarding prenephrectomy clinicopathologic variables. Dogs were reexamined prospectively at various times after nephrectomy, and pre- and postnephrectomy CBC, serum biochemical analyses, urinalysis, and urine protein-to-urine creatinine ratio were compared. Six dogs had postnephrectomy renal volume determined ultrasonographically, and 4 of those dogs also underwent scintigraphic determination of glomerular filtration rate and renal biopsy. RESULTS: All dogs were clinically normal at the time of reevaluation. There were no significant differences between prenephrectomy and postnephrectomy values for BUN concentration or urine specific gravity. Mean postnephrectomy serum creatinine concentration was significantly greater than prenephrectomy concentration. Mean serum phosphorus concentration was significantly decreased after nephrectomy, and mean Hct, corpuscular volume, and corpuscular hemoglobin concentration were significantly increased after nephrectomy. Postnephrectomy renal volume was greatest in dogs < 12 months old at the time of surgery. Mean postnephrectomy glomerular filtration rate was 2.82 +/- 1.12 mL/kg/ min (1.28 +/- 0.51 mL/lb/min). Renal biopsy specimens obtained during and after nephrectomy were histologically normal. CONCLUSIONS AND CLINICAL RELEVANCE: Renal and hematopoietic variables were within reference ranges in dogs examined up to 2.5 years after unilateral nephrectomy. Compensatory renal hypertrophy was greatest in dogs < 1 year of age at donation. Donor age, along with histocompatability, may be an important factor in selecting dogs for kidney donation.     

Characterization of the renal response to protein ingestion in dogs with experimentally induced renal failure.

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 less than 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 less than 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 less than 0.01, R2 = 0.721).     

Familial renal disease in Soft-coated Wheaten Terriers

In two litters of Soft-coated Wheaten Terriers, having the same parents, chronic renal failure developed in five out of ten dogs. The dogs died, or were destroyed on humane grounds, at 7 to 30 months of age. Clinical signs were inappetence, weight loss, vomiting, depression and, in two cases, polydipsia and polyuria. The laboratory data revealed isosthenuria, non-regenerative anaemia, extremely high serum urea nitrogen, and creatinine values. Pathoanatomical findings included small kidneys with an irregular and pale external surface. Cortical lesions were mostly segmental in distribution, and consisted of loss of glomerular elements and increased interstitial connective tissue. Medullary lesions were severe, diffuse in distribution, and consisted of loss of tubules and proliferation of connective tissue. The clinical, laboratory, and pathoanatomical findings show similarities to renal diseases seen in young dogs of other breeds.     

Free light-chain proteinuria and normal renal histopathology and function in 11 dogs exposed to Lleishmania infantum, Ehrlichia canis, and Bbabesia canis

The purpose of this retrospective study was to investigate the relationship among proteinuria consisting of immunoglobulin free light chains (FLCs), renal histopathologic findings, and routine markers of renal function in 11 dogs exposed to Leishmania infantum (n = 8), Ehrlichia canis (n = 2), and Babesia canis (n = 1). FLC proteinuria was suspected based on identification of a 22- to 27-kDa band by sodium dodecyl sulfate-agarose gel electrophoresis (SDS-AGE) and later confirmed by immunofixation electrophoresis. SDS-AGE identified an isolated band of 22-27 kDa in 8 dogs, whereas the remaining 3 had a 22- to 27-kDa band and an additional band of 67-72 kDa. The median urine protein-to-urine creatinine ratio was 0.37 (range, 0.11-2.24) and increased ratios were found in 6 dogs (54.5%) (reference value, <0.7). All dogs underwent histologic examination of renal percutaneous biopsy specimens and determination of serum creatinine and urea concentrations. Tissue samples for light microscopy were stained with hematoxylin-eosin, periodic acid-Schiff, Goldners trichrome, and methenamine silver. In the study group, the glomerular tufts, mesangium, tubulointerstitium, and vessels appeared unaffected. The median serum creatinine concentration in these 11 dogs was 1.3 mg/dL (range, 0.8-1.5 mg/dL; reference range, 0.6-1.5 mg/dL), whereas the concentration for urea was 28 mg/dL (range, 22-52 mg/dL; reference range, 20-50 mg/dL). All dogs had normal renal morphology and had normal serum creatinine and urea concentrations, suggesting that immunoglobulin FLC may be detected in the urine of dogs exposed to L. infantum, E. canis, and B. canis without any apparent structural or functional renal derangement.     

Changes in urea nitrogen and creatinine concentrations in the vitreous humor of cattle after death

The mean urea nitrogen concentration in vitreous humor (VUN) in 97 healthy steers after death was 15.7 mg/dl. The mean serum urea nitrogen concentration in the same cattle was 20.0 mg/dl. The mean vitreous creatinine (VC) concentration was 0.7 mg/dl, and the serum creatinine value was 1.5 mg/dl. The VUN and VC were both significantly lower than serum urea nitrogen and serum creatinine, respectively, but varied in a consistent, predictable manner. In tests with 10 cows, postmortem intervals as long as 36 hours and ambient temperatures up to 30 C had no significant effects on VUN and VC. Evaluation of 8 animals with uremia confirmed that the vitreous humor is a stable fluid compartment after death, usable as an indicator of serum urea nitrogen and creatinine.     

Ureterocolonic anastomosis in clinically normal dogs

Ureterocolonic anastomosis was evaluated in 13 clinically normal dogs. Urinary continence was maintained after surgery, and the procedure was completed without technique errors in all but 2 dogs. Three dogs died within 5 weeks (2 of undetermined causes and 1 of aspiration pneumonia and neurologic disease), and 1 dog was euthanatized 4 months after surgery because of neurologic signs. Two healthy dogs were euthanatized 3 months after surgery for light microscopic evaluation of their kidneys. Five dogs were euthanatized 6 months after surgery for light microscopic evaluation of their kidneys. Gastrointestinal and neurologic disturbances developed in 4 dogs at various postoperative intervals. Plasma ammonia concentration measured in 2 dogs with neurologic signs was increased. Plasma ammonia concentration measured in 5 dogs without neurologic signs was within normal limits. All 5 dogs, in which metabolic acidosis was diagnosed, had high normal or above normal serum chloride concentration. Serum urea nitrogen values were increased after surgery because of colonic absorption of urea. Serum creatinine concentration was increased in 1 dog 6 months after surgery. Individual kidney glomerular filtration rate was reduced in 38% (3/8) of the kidneys from 4 other dogs at 6 months after surgery. Of 5 dogs euthanatized at 3 to 4 months after surgery, 4 had bilateral pyelitis, and 1 had unilateral pyelonephritis. Six months after surgery, pyelonephritis was diagnosed in 40% (4/10) of the kidneys from 5 dogs. The ureterocolonic anastomosis procedure is a salvage procedure that should allow complete cystectomy. However, variable degrees of metabolic acidosis, hyperammonemia, and neurologic disease may result.     

QUANTITATIVE AND QUALITATIVE SCINTIGRAPHIC MEASUREMENT OF RENAL FUNCTION IN DOGS EXPOSED TO TOXIC DOSES OF GENTAMICIN

Five, 3-month-old mongrel dogs weighing between 4.5 to 5.5 kg were studied to evaluate and compare the efficiency of 99mTc-DTPA, 99mTc-MAG3, and 99mTc-DMSA in detecting gentamicin-induced renal tubular injury. After baseline renograms using all three methods, all dogs received daily intramuscular injections of gentamicin at a dose of 30-45 mg/kg. Additional studies were obtained after a cumulative dose of 450, 1,575, and 2,250 mg of gentamicin was reached. Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and percentage of total renal uptake measurements were calculated. Baseline and post-gentamicin injection blood urea nitrogen (BUN) and serum creatinine values were determined. A Duncan test revealed significant renal function impairment at 450 mgs of cumulated gentamicin with 99mTc-DMSA and at 1,575 mgs of cumulated gentamicin for 99mTc-DTPA and 99mTc-MAG3. There was no correlation between BUN and serum creatinine values when compared to gentamicin (p > 0.05). The images obtained with 99mTc-MAG3 were of better quality than those obtained with 99mTc-DTPA even under severe renal dysfunction. Percentage of 99mTc-DMSA uptake indicated renal damage, before than GFR and ERPF. BUN and serum creatinine measurements were poor indicators of gentamicin-induced renal failure.     

Histopathologic features of canine uremic gastropathy: a retrospective study

Uremic gastritis is a term commonly used to describe the gastrointestinal signs and histopathologic changes associated with renal failure in the dog. This retrospective study reviews the clinical, serum biochemical, and postmortem histopathologic data from 28 dogs with renal failure to determine the prevalence of gastric histopathology, characterize the gastric histopathology, and identify associations between gastric histopathology and serum concentrations of blood urea nitrogen (BUN), creatinine (Cr), calcium-phosphorus product (Ca x Phos), and hematocrit. Affected and control dogs with available renal and gastric tissue, serum biochemistry data, and urinalysis data were identified over a 10-year period (1992-2002) in the pathology department postmortem examination database at the Cornell University College of Veterinary Medicine. The serum biochemistry data and histopathologic findings were scored as normal, mild, moderate, and severe. All affected dogs had derangements of BUN, Cr, or Ca x Phos with gastric histopathology in 22 of 28 dogs (79%). Dogs with renal failure had a higher prevalence of gastric histopathologic changes compared with the control group. Associated histopathologic changes in the stomach were edema (P = .008), mineralization (P = .03), and vasculopathy (P = .03). Only 1 dog had evidence of gastric ulceration. Gastric necrosis was an uncommon finding (4/28, 14%). Gastric histopathology appears to be common in dogs with renal failure and is associated with increasing severity in the serum biochemistry data. Unlike humans with renal failure, in whom gastric ulceration predominates, gastric necrosis and ulceration appear to be uncommon in dogs with renal failure.     

Serum chemistry alterations in Alaskan sled dogs during five successive days of prolonged endurance exercise

OBJECTIVE: To determine the impact of successive days of endurance exercise on select serum chemistry values in conditioned Alaskan sled dogs. DESIGN: Prospective cohort study. ANIMALS: 10 conditioned Alaskan sled dogs. PROCEDURES: All dogs ran 160 km/d for 5 consecutive days. Serum was obtained prior to exercise and immediately after each exercise run; all samples were obtained before dogs were fed. Serum electrolyte, mineral, protein, total bilirubin, urea nitrogen, creatinine, and cardiac troponin-I concentrations and serum alkaline phosphatase, alanine aminotransferase, creatine kinase, and aspartate aminotransferase activities were measured. Data were analyzed by means of analysis of covariance for a randomized complete block design with dog as a blocking variable, time as a covariate, and distance run as the treatment of interest. Least square mean values were compared with values obtained prior to exercise, and linear and quadratic contrasts were examined. RESULTS: Serum globulin concentration was low prior to exercise (mean +/- SD, 2.2 +/- 0.3g/dL) and progressively decreased as exercise continued. Exercise was associated with increases in serum chloride, urea nitrogen, and cardiac troponin-I concentrations and serum alanine aminotransferase, creatine kinase, and aspartate aminotransferase activities and with progressive decreases in serum potassium, total protein, and albumin concentrations. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that multiple successive days of endurance exercise resulted in mild aberrations in serum chemistry variables in conditioned sled dogs. Changes likely reflected the metabolic stresses of prolonged endurance exercise as well as dietary composition. Hypoglobulinemia in resting, conditioned sled dogs may reflect the immunosuppressive or catabolic effects of intense endurance training.