Isoamylases in clinically normal dogs

Isoenzymes of canine serum amylase were evaluated by electrophoresis on cellulose acetate membranes in a discontinuous buffer system. Two isoamylase groups were identified in the serum of clinically normal dogs. Most of the serum amylase activity was the more cathodal isoamylase. The anodal isoamylase was rarely observed in serum from normal dogs and, when present, accounted for little of the enzymatic activity. Amylase activities of various tissues were determined and isoenzymes were identified. The anodal isoenzyme was found in the pancreas and uterus. The cathodal isoamylase had its origin mainly from the intestinal tract. Activities of other tissues were not greater than was serum amylase activity. Effects of feeding upon total serum amylase activity and isoenzyme composition also were examined over a period of 5 minutes to 7 hours. Feeding did not markedly alter the serum amylase activity.     

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.     

Diseased dogs isoamylases in clinically normal and diseased dogs

Isoamylases in normal canine sera were separated on cellulose acetate membranes using a discontinuous buffer system without EDTA. Four peaks of amylase activity were present in 17 of 24 sera. Normal values were established. The majority of activity was present in Peak 4 (cathodal isoamylase). Tissue extracts of pancreas, duodenum, kidney, lung, testis, spleen and uterus-ovaries contained Peak 4 isoamylase. Liver and salivary gland lacked all isoamylase activity. Pancreas contained Peak 3 in addition to Peak 4 isoamylase. A tissue origin for Peaks 1 and 2 was not identified. An overall lack of resolution resulted from the inclusion of EDTA in the electrophoresis buffer system. This may account for previous findings suggesting that pancreatic amylase is not present in normal canine serum. An increase in the Peak 3 isoamylase was present in dogs with pancreatitis while dogs with pancreatic atrophy had a decrease in all isoamylases. Total amylase activity was significantly (p < 0.05) decreased in dogs with pancreatic atrophy.     

Impedance audiometric measurements in clinically normal dogs

OBJECTIVE: To measure impedance audiometric values in clinically normal dogs that were sedated or anesthetized, evaluate effects of ear flushing on tympanometric measurements, and determine effects of performing acoustic reflex testing in a sound-attenuated room. ANIMALS: 35 mixed-breed and purebred client-owned dogs and 21 laboratory-bred Beagles. PROCEDURES: Tympanometry and acoustic reflex testing were performed on 27 mixed-breed and purebred dogs under isoflurane anesthesia in a non-sound-attenuated room and 21 Beagles under sedation in a sound-attenuated room. Tympanometry was performed on 8 mixed-breed dogs under halothane anesthesia before and after ear canal flushing. RESULTS: Among impedance audiometric values, ear canal volume and compliance peak were smaller in Beagles than in mixed-breed dogs; differences among other values were not detected. Ear canal volume was dependent on body weight. Differences were not found for tympanometric values measured before and after ear canal flushing. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study established reference range values for impedance audiometric measurements in clinically normal dogs under isoflurane anesthesia or sedation. Acoustic reflex testing does not need to be performed in a sound-attenuated room. The ear canals of clinically normal dogs can be flushed prior to performing tympanometry without altering the results. Impedance audiometry may be a useful noninvasive procedure for the diagnosis of otitis media in dogs.     

Effect of low doses of cosyntropin on serum cortisol concentrations in clinically normal dogs

OBJECTIVE: To determine the lowest of 5 doses of cosyntropin (1.0, 0.5, 0.1, 0.05, or 0.01 microg/kg) administered IV that stimulates maximal cortisol secretion in clinically normal dogs. ANIMALS: 10 clinically normal dogs. PROCEDURES: 5 dose-response experiments were performed in each of the dogs. Each dog received 5 doses of cosyntropin (1.0, 0.5, 0.1, 0.05, and 0.01 microg/kg) IV in random order (2-week interval between each dose). Serum samples for determination of cortisol concentrations were obtained before (baseline) and at 10, 20, 30, 40, 50, 60, 120, and 240 minutes after cosyntropin administration. RESULTS: Compared with baseline values, mean serum cortisol concentration in the study dogs increased significantly after administration of each of the 5 cosyntropin doses. Mean peak serum cortisol concentration was significantly lower after administration of 0.01, 0.05, and 0.1 microg of cosyntropin/kg, compared with findings after administration of 0.5 and 1.0 microg of cosyntropin/kg. After administration of 0.5 and 1.0 microg of cosyntropin/kg, mean peak serum cortisol concentration did not differ significantly; higher doses of cosyntropin resulted in more sustained increases in serum cortisol concentration, and peak response developed after a longer interval. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of cosyntropin IV at a dose of 0.5 microg/kg induced maximal cortisol secretion in healthy dogs. Serum cortisol concentration was reliably increased in all dogs after the administration of each of the 5 doses of cosyntropin. These data should be useful in subsequent studies to evaluate the hypothalamic-pituitary-adrenal axis in healthy and critically ill dogs.     

Telomerase activity in clinically normal dogs and dogs with malignant lymphoma

OBJECTIVES: To determine whether telomerase activity was present in lymph nodes, buffy coat, and serum samples from dogs with malignant lymphoma (ML) and in liver, lymph node, buffy coat, and serum samples from clinically normal dogs SAMPLE POPULATION: Tissue specimens and blood samples were obtained from 11 clinically normal adult dogs (age range, 1 to 4 years) and 14 client-owned dogs with ML. PROCEDURE: The telomere repeat amplification protocol assay was used to quantify telomerase activity in the tissues from clinically normal dogs and dogs with ML. RESULTS: Of 11 clinically normal dogs, 8 had lymph node samples, 5 had liver samples, and 1 had buffy coat samples with detectable telomerase activity. None of the serum samples from the clinically normal dogs had detectable telomerase activity. Of 14 dogs with ML, 9 had lymph node samples, 3 had buffy coat samples, and 1 had serum samples with measurable telomerase activity. CONCLUSIONS AND CLINICAL RELEVANCE: Telomerase activity was not specific to tumor cells and overlapped with that found in cells from clinically normal dogs. Telomerase activity in neoplastic lymph nodes was not substantially different from that found in lymph nodes from clinically normal dogs. The determination of telomerase activity cannot be used as a sole diagnostic test for cancer. Therapeutic modalities directed toward the telomerase enzyme may not be feasible in dogs, because somatic tissues from clinically normal dogs possess variable amounts of telomerase activity.     

Effect of administration of nonsteroidal anti-inflammatory drugs before surgery on renal function in clinically normal dogs

OBJECTIVES: To investigate renal function in clinically normal dogs undergoing general anesthesia for ovariohysterectomies that received nonsteriodal antiinflammatory drugs (NSAID) before surgery. ANIMALS: 40 clinically normal dogs. PROCEDURE: After induction of anesthesia, dogs were given an analgesic. Renal function was assessed before surgery and 24 and 48 hours after surgery by means of serum urea and creatinine concentrations, fractional clearance of sodium (FC(Na)), urine gamma-glutamyltransferase (GGT) and alkaline phosphatase (ALP) activities, and urine analysis. Ten dogs in each of 4 groups received ketorolac tromethamine (0.5 mg/kg of body weight), ketoprofen (1 mg/kg), carprofen (4 mg/kg), or morphine (0.1 mg/kg; control group). RESULTS: Duration of general anesthesia ranged from 1.75 to 5 hours, with a mean of 3 hours. Two ketorolac- and 2 ketoprofen-treated dogs had transient azotemia. A significant decrease in the FC(Na) between before surgery and 24 hours after surgery, and between before surgery and 48 hours after surgery, was found in ketoprofen- and carprofen-treated dogs. Ketorolac-, ketoprofen-, and morphine-treated dogs had a decrease in urine specific gravity. Two ketorolac, 1 ketoprofen-, 1 carprofen-, and 4 morphine-treated dogs had increases in renal tubular epithelial cells on urine sediment examination 24 hours after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: In clinically normal dogs undergoing general anesthesia and elective surgery, the use of NSAID as analgesics is not contraindicated. Compared with ketorolac or ketoprofen, carprofen had the least effect on renal function and integrity.     

Effects of mitotane therapy in dogs with pituitary dependent Cushing syndrome on the adrenal gland size--an ultrasonographic study]

The effect of mitotane therapy on adrenal gland size was evaluated in 13 dogs with pituitary dependent hyperadrenocorticism. Ultrasonographic measurements were obtained before and during mitotane therapy. During therapy both adrenal glands were shorter and thinner (median during therapy: left adrenal gland 19.4 mm long, 5.4 mm thick, right adrenal gland 18.1 mm long, 6.1 mm thick) than before mitotane therapy (median before therapy: left adrenal gland 23.6 mm long, 8.3 mm thick, right adrenal gland 21.6 mm long, 8.1 mm thick). Statistical evaluation showed a significant reduction in size. But ultrasonographic measurement of adrenal gland size is not useful in the evaluation of adrenal reserve during mitotane therapy. Inadequate adrenal reserve was not identified and adrenal size measurement by ultrasonography was not helpful to differentiate adequate and inadequate control of adrenal cortisol secretion during mitotane therapy.     

Osmotic fragility of erythrocytes in clinically normal dogs and dogs infected with parasites

The osmotic fragility of the erythrocytes was measured in blood samples collected from randomly selected healthy and infected dogs at a dogs' rescue shelter. The dogs were classified into six groups on the basis of the final diagnoses from clinical, post mortem and laboratory findings. The minimum (less than 5 per cent) and maximum (more than 90 per cent) haemolysis of the erythrocytes of the clinically normal dogs (group 1), occurred in 0·60 per cent and 0·30 per cent solutions of sodium chloride (NaCI). For the non-anaemic hookworm-infected dogs (group 2a) the respective values were 0·8 per cent and 0·4 per cent NaCl, and for the anaemic hookworm-infected dogs (group 2b) they were 0·85 per cent and 0·5 per cent NaCl, respectively. The erythrocytes from dogs with Babesia canis (group 3), concurrent hookworm and B canis (group 4) and Ehrlichia canis infections (group 5) had minimum haemolysis in 0·75 per cent NaCl and maximum haemolysis at between 0·20 per cent and 0·35 per cent NaCI solutions. The derivative fragiligrams for groups 2a, 2b, 3 and 4 were shifted to the left, whereas the fragiligram for group 5 was similar to that for the clinically normal dogs (group 1). The left shift for the hookworm-infected dogs was due to the increased osmotic fragility of a minor sub-population of the erythrocytes, but for the dogs, infected with B canis major sub-populations of the erythrocytes had an increased osmotic fragility.     

Nuclear scintigraphic assessment of liver size in clinically normal dogs

Measurement of liver size was made on nuclear scintigraphic images obtained from 16 clinically normal, anesthetized dogs in ventral, dorsal, right and left lateral, and left dorsal oblique positions after administration of technetium 99m-sulfur colloid. Linear measurements of liver length and width were made from each scintiscan, and liver surface area was determined by setting a region of interest manually and by use of a computer count of pixels above a minimal intensity (threshold method). All linear measurements had a statistically significant (P less than 0.05) correlation with liver and body weight, with the exception of the measurements of liver width made on dogs in dorsal and left lateral dorsal oblique positions. The highest correlation (r = 0.89) between the scintigraphic measurements and liver weight was the multiplication of measurements of liver width and length from the right lateral view. Although all area determinations were significantly (P less than 0.05) correlated with liver and body weight, for most views, the manual method of determining the region of interest had a slightly better correlation with the liver weight than did the threshold method.     

Quantitative noninvasive assessment of liver size in clinically normal dogs

Measurements of liver size were made from radiographs of 16 clinically normal anesthetized dogs. Two measurements were made from each of 3 views: right and left lateral and ventrodorsal. Each measurement was correlated with liver weight and volume. Liver weight and volume were also correlated with both measurements from the same radiograph multiplied together. All measurements, with the exception of ventrodorsal depth, correlated significantly (P less than 0.05) with liver weight and volume. The multiplication of the 2 measurements made from the right lateral radiograph correlated most highly with liver weight. These data were then compared with those from similar studies involving liver measurements obtained from nuclear scintigraphic and ultrasonographic scans on the same dogs. The radiographic measurements made from the right lateral view had the highest correlation with liver weight, followed by the nuclear scintigraphic measurements made from the same position.     

High-frequency ultrasonography of the skin of clinically normal dogs

OBJECTIVE: To assess the applicability of high-frequency diagnostic ultrasonography for evaluation and accurate measurement of the skin thickness of clinically normal dogs. ANIMALS: 26 healthy dogs (12 sexually intact males, 13 sexually intact females, and 1 spayed female) of various breeds and ages. PROCEDURE: Ultrasonographic examination of the skin and histomorphometric analysis of skin biopsy specimens obtained from the same site were performed. A 13-MHz linear-array transducer was used to obtain a series of ultrasonographic images of the skin in the flank region; images were analyzed and measured by use of imaging software. Cutaneous biopsy specimens were placed in fixative and then stained with H&E and Masson trichrome stains. Histomorphometric analysis was performed by use of an image analyzer. Thickness of the epidermis and dermis of each specimen was evaluated by use of a semiautomatic procedure of quantification. Data obtained from ultrasonographic and histologic measurements were compared by use of the Pearson correlation test. RESULTS: The ultrasonographic pattern of canine skin was consistently characterized by 3 distinct, defined echogenic layers corresponding to the epidermal entry echo, epidermis and dermis, and subcutaneous tissues. A positive correlation was found between ultrasonographic and histologic measurements of skin thickness. CONCLUSIONS AND CLINICAL RELEVANCE: Comparison between ultrasonographic and histologic appearance of the skin revealed that layering of canine skin (ie, epidermis and dermis) and the subcutaneous tissues may be recognized and measured by use of high-frequency ultrasonography. Thus, diagnostic ultrasonography may be a useful tool for the noninvasive evaluation of cutaneous disorders in dogs.     

Nitrogen balance in clinically normal dogs receiving parenteral nutrition solutions

OBJECTIVE: To determine nitrogen balance in clinically normal dogs receiving parenteral nutrition solutions. ANIMALS: 8 clinically normal female Beagles. PROCEDURE: Dogs were randomly assigned to receive 4 treatments in random order. Treatment A consisted of IV administration of nonlactated Ringer's solution. Treatments B, C, and D consisted of IV administration of isocaloric parenteral solutions containing 0, 1.36, and 2.04 g of amino acids/kg of body weight/d, respectively, for 7 consecutive days. Urine and feces were collected on days 5, 6, and 7 of each treatment period, and Kjeldahl analysis was used to determine nitrogen balance. RESULTS: Mean nitrogen balance was negative with treatments A and B but was not significantly different from 0 with treatments C and D. Dogs had the lowest nitrogen balance values and lost the most weight while receiving treatment A. Dogs were able to conserve protein and had higher nitrogen balance values when receiving treatment B, compared with treatment A. Dogs lost the least amount of weight while receiving treatment D. Regression analysis indicated that an IV amino acid intake of 2.32 g/kg/d (95% confidence interval, 2.00 to 2.81 g/kg/d), as supplied by the commercial product used in this study, would result in zero nitrogen balance in clinically normal dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that IV amino acid requirement of clinically normal dogs is approximately 2.3 g/kg/d.     

Effects of chlorothiazide on urinary excretion of calcium in clinically normal dogs.

Administration of thiazide diuretics has been recommended to prevent calcium oxalate urolith development in dogs. To evaluate the effects of thiazide diuretics in dogs, 24-hour urine excretion of calcium was measured in 6 clinically normal Beagles after administration of chlorothiazide (CTZ) for 2 weeks, administration of CTZ for 10 weeks, and administration of calcium carbonate and CTZ for 2 weeks. Compared with baseline values, 24-hour urine calcium excretion did not decrease after CTZ administration. When CTZ was given at a high dosage (130 mg/kg of body weight), urinary calcium excretion was significantly (P < 0.04) higher than baseline values. Based on these observations, we do not recommend CTZ for treatment or prevention of canine calcium oxalate urolithiasis.     

Fluorophotometric determination of aqueous humor flow rate in clinically normal dogs

OBJECTIVE: To determine aqueous humor flow rate in clinically normal dogs, using fluorophotometry. ANIMALS: 20 clinically normal Beagles. PROCEDURE: A study was performed on 5 dogs to establish an optimal protocol for fluorophotometric determination of aqueous humor flow rate. This protocol then was used to measure aqueous humor flow rate in 15 dogs. Corneas were loaded with fluorescein by topical application, and corneal and aqueous humor fluorescein concentrations were measured 5, 6.5, and 8 hours after application. Concentration-versus-time plots were generated, and slopes and ratios of the fluorescein concentration in the cornea and aqueous humor from these graphs were used to calculate flow rates. Calculations were performed by use of automated software provided with the fluorophotometer and by manual computation, and the 2 calculation methods were compared. RESULTS: The protocol established for the 5 dogs resulted in semilogarithmic and parallel decay of corneal and aqueous humor concentrations. Manually calculated mean +/- SD aqueous humor flow rates for left, right, and both eyes were 5.58 +/- 2.42, 4.86 +/- 2.49, and 5.22 +/- 1.87 microl/min, respectively, whereas corresponding flow rates calculated by use of the automated software were 4.54 +/- 3.08, 4.54 +/- 3.10, and 4.54 +/- 2.57 microl/min, respectively. Values for the left eye were significantly different between the 2 computation methods. CONCLUSIONS AND CLINICAL RELEVANCE: Aqueous humor flow rates can be determined in dogs, using fluorophotometry. This technique can be used to assess pathologic states and medical and surgical treatments that alter aqueous humor dynamics.     

Computed tomographic osteoabsorptiometry of the elbow joint in clinically normal dogs

OBJECTIVE: To evaluate subchondral bone density patterns in elbow joints of clinically normal dogs by use of computed tomographic (CT) osteoabsorptiometry. SAMPLE POPULATION: 20 cadaver forelimbs from 10 clinically normal dogs. PROCEDURE: Each elbow joint was imaged in parasagittal and transverse planes of 1.5-mm thickness. Slice data were converted to dipotassium phosphate equivalent density (PPED) values. Sagittal, parasagittal, and transverse medial coronoid process topographic maps were constructed. Defined zones were created for each of the 3 CT planes, and confluence and peak PPED values were determined. RESULTS: The lowest PPED value was 340 mg/ml (articular and subchondral confluence), and the highest was 1780 mg/ml (peak subchondral density). Detectable effects of joint laterality were not found in the confluence or peak PPED measurements or in the peak-to-confluence PPED ratio for all 3 CT planes. Significant differences were found among zones in all 3 planes for confluence and peak PPED measurements and between sagittal and transverse planes for peak-to-confluence PPED ratios. Subjectively, the pattern of density distribution among dogs was fairly consistent for the sagittal and parasagittal slices. Three specific patterns of density distribution were apparent on the transverse topographic maps of the medial coronoid process that corresponded to conformational differences. CONCLUSIONS AND CLINICAL RELEVANCE: The use of CT osteoabsorptiometry provides a repeatable technique that can be used to noninvasively examine bone density and the effects of stress acting on joints in vivo. Variability in density values for any of the CT planes was not identified among clinically normal dogs.