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abdominal radiography. Cats were excluded from the study if they had received glucocorticoids or calcium-supplement-type nutritional products within the 2 years preceding the study. Cats lived with their owners, except during two 72-hour periods for urine

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in American Journal of Veterinary Research

beads used in the study were donated by Wedgewood Pharmacy. ABBREVIATIONS CSH Calcium sulfate semihydrate IC 50 Molar concentration of compound that inhibits specific activity by 50% Footnotes a. Hess T, Miller J, Fettig A, et al

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in American Journal of Veterinary Research

Summary:

Various nutrious nutritional-supplement gels are being marketed for use in veterinary medicine. This study was designed to determine whether serum calcium, phosphorous, or magnesium concentrations were different between cows given a gel containing calcium chloride as its active ingredient (treated) and cows given inert carrier gel (control). The study revealed a significant (P < 0.01) increase in serum total calcium concentration within 5 minutes of administration of a calcium gel given to cows within 1 hour of parturition. Serum total calcium concentration had returned to baseline value by 24 hours after calcium gel administration. Serum inorganic phosphorus concentration also increased significantly (P < 0.05) after treatment. Significant changes in serum magnesium concentrations were not detected.

Free access
in Journal of the American Veterinary Medical Association

either total or ionized calcium concentration and provides a clinically relevant means of estimating cardiovascular risk associated with CKD. 4 Bone disorders and mineral disorders represent interrelated serum biochemical, bone, and vasculature

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in Journal of the American Veterinary Medical Association

SUMMARY

We tested the hypothesis that lymphocytes from swine with susceptibility to malignant hyperthermia (mh) had calcium extrusion activity higher than unaffected swine. Cytoplasmic concentration of ionized calcium was determined by use of dual emission spectrofluorometry and measurement of the ratio of free to calcium-bound form of the fluorescent calcium dye indo-1. Net calcium accumulation and unidirectional calcium extrusion rate were dependent on intracellular calcium concentration. Calcium extrusion from calcium-loaded lymphocytes was monitored while calcium influx was inhibited by suspending the cells in calcium-free medium with a calcium chelator. Net calcium accumulation of untreated lymphocytes was monitored in calcium-replete medium. A novel method of calculation of ionized calcium was used. This method confirmed our previous findings of lower ionized calcium concentration (86 ± 40 and 370 ± 216 nmol/L; P < 0.01) and slower rates of calcium accumulation 39 ± 16 and 127 ± 52 nmol/L/min) in untreated lymphocytes from mh-susceptible swine compared with controls. These changes were attributable to calcium extrusion activity two- to three-fold higher in lymphocytes of mh-susceptible swine (154 ± 36 and 408 ± 47 nmol/L/min at 175 nmol/L; 972 ± 111 and 1,690 ± 505 nmol/L/min at 425 nmol/L). These data were compatible with our model of higher calcium extrusion activity being a compensatory adaptation of mh-susceptible swine lymphocytes to their hypersensitivity to stimuli that increase cytoplasmic calcium concentration.

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether total serum calcium (tCa) or adjusted tCa concentrations accurately predict ionized calcium (iCa) status in dogs.

Sample Population—1,633 canine serum samples.

Procedure—The tCa concentration was adjusted for total protein (TP) or albumin concentration by use of published equations. Correlations between iCa and tCa or adjusted tCa, tCa and TP, and tCa and albumin were calculated. Diagnostic discordance between tCa or adjusted tCa and iCa was determined. Diagnostic discordance in predicting iCa was also determined for 490 dogs with chronic renal failure (CRF). Sensitivity, specificity, positive and negative predictive values, and positive and negative diagnostic likelihood ratios were calculated for tCa, tCa adjusted for TP, and tCa adjusted for albumin.

Results—Diagnostic discordance was 27% when tCa concentration was used to predict iCa status. Use of adjusted tCa increased diagnostic discordance to approximately 37% for all dogs and 55% for dogs with CRF. Positive predictive value and positive diagnostic likelihood ratios were poor when tCa concentration was used to predict iCa status. The tCa concentration overestimated normocalcemia and underestimated hypocalcemia. Adjusted tCa overestimated hypercalcemia and underestimated hypocalcemia.

Conclusions and Clinical Relevance—Adjusted tCa or tCa concentrations are unacceptable for predicting iCa status in dogs. Use of adjustment equations is not recommended. Direct measurement of iCa concentration is necessary for accurate assessment of calcium status. Use of tCa or adjusted tCa concentrations to predict iCa status in dogs could cause serious mistakes in diagnosis and case management, especially in dogs with CRF. (Am J Vet Res 2005;66:1330–1336)

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in American Journal of Veterinary Research

SUMMARY

Epidemiologic data were evaluated from all dogs admitted to the University of Minnesota, Veterinary Teaching Hospital (UMVTH) between June 1981 and November 1989. Of 69,890 admissions, 2,077 were Miniature Schnauzers. Uroliths were retrieved from 63 of the 2,077 Miniature Schnauzers admitted. In 20 of the 63 urolith episodes, calcium oxalate was the predominant mineral identified. By comparison, calcium oxalate uroliths were identified in only 56 of the remaining 67,813 non-Miniature Schnauzer canine admissions. The odds that uroliths from Miniature Schnauzers were composed of calcium oxalate was 11.8 times greater than for other canine breeds evaluated at the UMVTH (95% confidence interval = 6.8 to 20.1).

Data also were evaluated from files of uroliths retrieved from dogs and submitted to the Minnesota Urolith Center for quantitative mineral analysis between June 1981 and November 1989. Of 3,930 uroliths analyzed, 615 (15.6%) uroliths were obtained from Miniature Schnauzers. Of the 615 uroliths, 175 (28.4%) were calcium oxalate. By comparison, only 550 (16.6%) of the remaining 3,315 from dogs of breeds other than Miniature Schnauzers were calcium oxalate. The odds that uroliths submitted for analysis were composed of calcium oxalate was 2 times greater for Miniature Schnauzers than for dogs of other breeds (95% confidence interval = 1.6 to 2.4).

Calcium oxalate uroliths were retrieved more frequently in males than females. The risk for males developing calcium oxalate uroliths was > 3 times the risk for females in both groups of data evaluated. The mean age of all Miniature Schnauzers admitted to the UMVTH with calcium oxalate uroliths was 9 years. Calcium oxalate uroliths were not detected in Miniature Schnauzers younger than 1.7 years.

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in American Journal of Veterinary Research

citrate, with nonsphering of platelets in citrate also potentially causing an artifactual increase in MPV. 1 Citrate, which chelates positively charged calcium ions and thereby blocks calcium-dependent clotting factor reactions, is the anticoagulant

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in American Journal of Veterinary Research

, 15 One study by Nelson and colleagues demonstrated that tobramycin concentrations in wound exudates from experimentally induced osteomyelitis in rabbits reached 11.9 mg/mL when treated with impregnated calcium sulfate (CaSO 4 ) pellets. Serum

Open access
in American Journal of Veterinary Research

Summary

Twenty-four dogs with induced, severe chronic renal failure were allotted to 2 groups of 12 each. Group-A dogs were fed a 0.4% phosphorus (P)/0.6% calcium, 32% protein diet, and group-B dogs were fed a 1.4% P/l.9% calcium, 32% protein diet. Dogs were studied over 24 months to determine clinical status, survival, blood biochemical alterations, glomerular filtration rate (gfr), urinary excretion of P and protein, renal morphologic changes, and renal tissue concentrations of calcium, P, and magnesium.

Group-A dogs developed statistically significant differences from group-B dogs in several blood biochemical values (pcv and total solids, calcium, P, potassium, sodium, chlonde, total CO2 (TCO2), anion gap, and parathyroid hormone concentrations) and in urinary P excretion.

Mean ( ± sem) gfr values in group-A and group-B dogs were nearly identical when diets were initiated (group _A = 0.73 ± 0.05 ml/min/kg of body weight; group B = 0.72 ± 0.08 ml/min/kg), but significantly (P = 0.0346) lower gfr developed in group-B than in group-A dogs over time. At 24 months, gfr in survivors was 0.83 ± 0.08 and 0.63 ± 0.15 ml/min/kg for dogs of groups A and B, respectively.

Other measurements favored the hypothesis that P/calcium restriction was beneficial, but values failed to reach statistical significance. Survival was greater at 24 months in group-A than in group-B (7 vs 5) dogs, and renal tissue concentrations of calcium and P were higher in group-B than in group-A dogs.

Differences were not detected between groups in urinary excretion of protein and in the type or severity of renal lesions.

We conclude that P/calcium restriction at 32% protein intake is beneficial to dogs with chronic renal failure, but that the degree of restriction imposed in group-A dogs of this study did not prevent development of abnormalities. Factors other than dietary P/calcium intake may have a role in progression of renal failure to uremia.

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in American Journal of Veterinary Research