Renal electrolyte and net acid excretion were characterized during generation and maintenance of hypochloremic metabolic alkalosis in a ruminant model. Two phases of renal response with regard to sodium and net acid excretion were documented. An initial decrease in net acid excretion was attributable to increase in bicarbonate excretion with associated increase in sodium excretion. As the metabolic disturbance became more advanced, a second phase of renal excretion was observed in which sodium and bicarbonate excretion were markedly decreased, leading to increase in net acid excretion and development of aciduria. Throughout the metabolic disturbance, chloride excretion was markedly decreased; potassium excretion also decreased. These changes were accompanied by increase in plasma renin and aldosterone concentrations. There was apparent failure to concentrate the urine optimally during the course of the metabolic disturbance, despite increasing plasma concentration of antidiuretic hormone.

Skeletal muscles from healthy dogs and Labrador Retrievers with hereditary muscular dystrophy were examined morphologically and histochemically and were analyzed biochemically for Na+, K+, Ca2+, Mg2+, Zn2+, Cu2+, Cl-, total muscle water, and total neutral lipid content. Flame atomic absorption spectrophotometer was used for elemental quantitation of hydrochloric acid tissue extracts. Muscle samples from dystrophic dogs contained substantially increased concentrations of Na+, Ca2+, Zn2+, Cu2+, and Cl-, and a considerable reduction in the content of K+ and Mg2+ compared with samples from healthy dogs. Total muscle water and total fat content was higher in muscles from dystrophic dogs. Most muscle samples from dystrophic dogs had a type-2 fiber deficiency and an increase in number of fibers with internalized nuclei.

OBJECTIVE To assess agreement between 2 benchtop blood gas analyzers developed by 1 manufacturer (BGA 1 and BGA 2 [a newer model with reduced maintenance requirements]) and a reference chemistry analyzer for measurement of electrolyte (sodium, chloride, and potassium) in blood samples from dogs. ANIMALS 17 healthy staff- and student-owned dogs and 23 client-owned dogs admitted to an emergency and intensive care service. PROCEDURES Blood collected by venipuncture was placed in lithium heparin–containing tubes. Aliquots were analyzed immediately with each BGA. Samples were centrifuged, and plasma was analyzed with the reference analyzer. Results for each BGA were compared with results for the reference analyzer by Passing-Bablok regression analysis. Percentage differences between BGA and reference analyzer results were compared with published guidelines for total allowable error. RESULTS Proportional bias was detected for measurement of chloride concentration (slope, 0.7; 95% CI, 0.7 to 0.8), and constant positive bias was detected for measurement of chloride (y-intercept, 34, mmol/L; 95% CI, 16.9 to 38 mmol/L) and potassium (y-intercept, 0.1 mmol/L; 95% CI, 0.1 to 0.2 mmol/L) concentrations with BGA 1. There was no significant bias for measurement of potassium or chloride concentration with BGA 2 or sodium concentration with either BGA. Differences from the reference analyzer result exceeded total allowable error guidelines for ≥ 1 sample/analyte/BGA, but median observed measurement differences between each BGA and the reference analyzer did not. CONCLUSIONS AND CLINICAL RELEVANCE Good agreement with reference analyzer results was found for measurement of the selected electrolyte concentrations in canine blood samples with each BGA.

OBJECTIVE To evaluate the diuretic effects and associated changes in hematologic and plasma biochemical values following SC furosemide administration to water-deprived inland bearded dragons (Pogona vitticeps). ANIMALS 9 bearded dragons. PROCEDURES In a crossover study design, furosemide (5 or 10 mg/kg) was administered SC every 12 hours for 4 doses or no treatment (control treatment) was provided for the same period. Food and water were withheld. Body weight was recorded before (baseline) and 12 hours after treatment sessions ended and then after 5 minutes of soaking in a water bath. Blood samples were collected at baseline and 12 hours after treatment sessions ended for various measurements. RESULTS Compared with control values, a significant decrease from baseline in body weight was detected after furosemide treatment at 5 and 10 mg/kg (mean ± SD percentage decrease, 5.5 ± 3.2% and 5.2 ± 4.1%, respectively). Soaking resulted in a significant increase in body weight after the 5- and 10-mg/kg furosemide treatments (mean ± SD percentage increase, 2.9 ± 1.8% and 5.6 ± 2.5%, respectively), compared with change in body weight after the control treatment (0.7 ± 0.7%). Plasma total solids and total protein concentrations increased significantly with both furosemide treatments, and PCV increased significantly with the 10 mg/kg treatment only. No significant or relevant differences were identified in plasma osmolarity or uric acid or electrolyte concentrations. CONCLUSIONS AND CLINICAL RELEVANCE Furosemide as administered resulted in hemoconcentration and weight loss in bearded dragons, most likely owing to its diuretic effects. With additional research, furosemide could be considered for treatment of congestive heart failure and other conditions requiring diuresis in bearded dragons.

The purpose of this study was to determine a wide range of selected hematologic, venous blood gases, and plasma biochemistry analytes in common chameleons (Chamaeleo chamaeleon). Blood samples were collected from the ventral tail vein of 41 common chameleons to determine reference intervals for 30 different blood analytes. The calcium-to-phosphorus ratio, packed cell volume (PCV), refractometric total solids (TS), blood cell counts, and differentials were also determined. The microscopic evaluation of blood smears revealed inclusion bodies in monocytes in 7 of the samples. Females showed significantly higher values of plasma proteins and calcium and cholesterol concentrations and males showed significantly higher values of aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT) plasma concentrations. Significant differences were found between similar analytes determined by different testing methodologies in the PCV/hematocrit, electrolytes (sodium, potassium), and plasma proteins [TS, total protein (TP) and albumin]. Blood analytes determined in this study can provide baseline data that may be useful when evaluating the health status of common chameleons, taking into consideration the potential effects of gender and the type of analyzer used.

OBJECTIVE To determine effects of 2 tiludronate administration protocols on measures of lameness in horses with navicular syndrome (NS). ANIMALS 12 horses with bilateral forelimb NS. PROCEDURES Horses were randomly assigned to receive tiludronate (1 mg/kg), diluted in 5 L of isotonic electrolyte solution and delivered through a jugular vein catheter (systemic treatment group; n = 6), or tiludronate (0.1 mg/kg), diluted with saline (0.9% NaCl) solution to a total volume of 35 mL and delivered into the lateral digital vein of each forelimb with an IV regional limb perfusion (IVRLP) technique (IVRLP group; 6). Mean peak vertical ground reaction force (pVGRF) measured with a stationary force plate and subjective lameness scores (SLSs) were recorded before (day −1) and at predetermined time points after tiludronate administration on day 0. Mean pVGRFs (standardized as percentage body weight of force) and mean SLSs for the most lame forelimb and for both forelimbs of horses in each group were compared with day −1 values to determine treatment effect. RESULTS Mean pVGRF for both forelimbs and for the most lame forelimbs of systemically treated horses were significantly increased on days 120 and 200, compared with day −1 results. No significant difference in mean pVGRF was observed for IVRLP-treated horses. The SLSs were not improved at any time point following systemic treatment and were improved only on day 120 following IVRLP. CONCLUSIONS AND CLINICAL RELEVANCE Tiludronate (1 mg/kg, IV) as a single systemic treatment appeared to be beneficial for horses with NS, but no horses were judged as sound during the study period. Additional research on IVRLP with tiludronate is needed before this method can be recommended.

OBJECTIVE To evaluate the tear film osmolality and electrolyte composition in healthy horses. ANIMALS 15 healthy adult horses. PROCEDURES Each horse was manually restrained, and an ophthalmic examination, which included slit-lamp biomicroscopy, indirect ophthalmoscopy, and a Schirmer tear test, was performed. Tear samples were collected from both eyes with microcapillary tubes 3 times at 5-minute intervals. The tear samples for each horse were pooled, and the osmolality and electrolyte concentrations were measured. The mean (SD) was calculated for each variable to establish preliminary guidelines for tear film osmolality and electrolyte composition in healthy horses. RESULTS The mean (SD) tear film osmolality was 283.51 (9.33) mmol/kg, and the mean (SD) sodium, potassium, magnesium, and calcium concentrations were 134.75 (10), 16.3 (5.77), 3.48 (1.97), and 1.06 (0.42) mmol/L, respectively. The sodium concentration in the tear film was similar to that in serum, whereas the potassium concentration in the tear film was approximately 4.75 times that of serum. CONCLUSIONS AND CLINICAL RELEVANCE Results provided preliminary guidelines with which tear samples obtained from horses with keratopathies can be compared. Measurement of tear film osmolality in these horses was easy and noninvasive. The tear film concentration of divalent cations was greater than expected and was higher than the divalent cation concentrations in the tear films of rabbits and humans. These data may be clinically useful for the diagnosis and monitoring of hyperosmolar ocular surface disease in horses.

This study aimed to investigate and compare the antagonistic effects of atipamezole, yohimbine, and prazosin on xylazine-induced diuresis in clinically normal cats. Five cats were repeatedly used in each of the 9 groups. One group was not medicated. Cats in the other groups received 2 mg/kg BW xylazine intramuscularly, and saline (as the control); 160 μg/kg BW prazosin; or 40, 160, or 480 μg/kg BW atipamezole or yohimbine intravenously 0.5 h later. Urine and blood samples were collected 10 times over 8 h. Urine volume, pH, and specific gravity; plasma arginine vasopressin (AVP) concentration; and creatinine, osmolality, and electrolyte values in both urine and plasma were measured. Both atipamezole and yohimbine antagonized xylazine-induced diuresis, but prazosin did not. The antidiuretic effect of atipamezole was more potent than that of yohimbine but not dose-dependent, in contrast to the effect of yohimbine at the tested doses. Both atipamezole and yohimbine reversed xylazine-induced decreases in both urine specific gravity and osmolality, and the increase in free water clearance. Glomerular filtration rate, osmolar clearance, and plasma electrolyte concentrations were not significantly altered. Antidiuresis of either atipamezole or yohimbine was not related to the area under the curve for AVP concentration, although the highest dose of both atipamezole and yohimbine increased plasma AVP concentration initially and temporarily, suggesting that this may in part influence antidiuretic effects of both agents. The diuretic effect of xylazine in cats may be mediated by α2-adrenoceptors but not α1-adrenoceptors. Atipamezole and yohimbine can be used as antagonistic agents against xylazine-induced diuresis in clinically normal cats.

Indices of renal function and damage were measured in 12 healthy male adult llamas fed a diet of mixed alfalfa/grass hay (mixed hay) and water ad libitum. Using a collection bag fitted over the preputial area, urine samples were collected at 6, 12, and 24 hours. Serum samples were obtained concurrently to determine endogenous creatinine clearance (CL), total (TE) and fractional excretion (FE) of electrolytes (Na, K, Cl, P), electrolyte CL, urine and serum osmolality, urine enzyme activities (gamma-glutamyltransferase and N-acetyl-beta-D-glucosaminidase), and urine protein concentration. Urine production was quantified. Three months later, 10 of the 12 llamas were fed a grass hay diet and water ad libitum. Similar samples were obtained, and similar measurements were made. Urine production was higher when the llamas were fed the mixed hay diet. Total urine volume for llamas fed mixed hay ranged from 628 to 1,760 ml/24 h, with a median of 1,307.5 ml/24 h, compared with a range of 620 to 1,380 ml/24 h and a median of 927.50 ml/24 h for llamas fed grass hay. Median urine osmolality was higher in llamas fed mixed hay (1,906 mOsm/kg of body weight, with a range of 1,237 to 2,529 mOsm/kg), compared with llamas fed grass hay (1,666 mOsm/kg with a range of 1,163 to 2,044 mOsm/kg). Creatinine CL did not vary significantly over time for either diet. Median creatinine CL was higher for llamas fed mixed hay, compared with llamas fed grass hay--0.78 ml/min/kg with a range of 0.20 to 1.83 ml/min/kg vs 0.45 ml/min/kg with a range of 0.13 to 3.17 ml/min/kg. Clearances for K and Cl varied significantly among the periods. However, median CL for Na and P did not vary over time for either diet. Overall values for these electrolytes in llamas fed mixed hay and grass hay diets were: CL(Na), 0.001 and 0.002 ml/min/kg and CL(P), 0.0006 and 0.0004 ml/min/kg respectively. The FE rates of K, Cl, and P did not vary significantly over time for either diet. Median respective FE for these electrolytes in the llamas fed mixed hay and grass hay diets include: FE(K), 84.90 and 63.10%; FE(Cl), 0.85 and 1.30%; and FE(P), 0.10 and 0.10%. Fractional excretion of Na varied over time for both diets and could not be expressed accurately as an overall median. Median respective TE of electrolytes for llamas fed the mixed hay and grass hay diets were: TE(Na), 0.007 and 0.03 mEq/kg/h; TE(Cl), 0.04 and 0.06 mEq/kg/h; and TE(P), 0.0002 and 0.00 mg/kg/h; TE(K) varied significantly (P < 0.05) over time for both diets. Urine gamma-glutamyltransferase activity changed significantly (P < 0.05) over time. Urine N-acetyl-beta-D-glucosaminidase activity was influenced by an interaction between diet and time. Median urine protein concentration was 26.0 mg/dl, with a range of 11.0 to 73.0 mg/dl for llamas fed mixed hay, and was 28.0 mg/dl, with a range of 16.0 to 124.0 mg/dl for llamas fed grass hay.

We investigated the effect of adding psyllium to a standard electrolyte solution in 10 calves with diarrhea. The calves were tested with the standard solution on one day and standard solution plus psyllium on the alternate day. The order of treatments was randomized. Psyllium converted the solution into mucilage, but did not affect fecal consistency. Mean +/- SEM area under the glucose absorption curve was lower for mucilaginous than for nonmucilaginous solutions, 2.1 +/- 0.62 vs 3.75 +/- 1.18 mmol.h, respectively, but the difference was not significant. The area under the breath hydrogen curve was marginally lower for mucilaginous than nonmucilaginous solutions, 102 +/- 20 and 209 +/- 60 ppm.h, respectively. The usefulness of such decreased bacterial fermentation is doubtful.