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  • Author or Editor: Elizabeth M. Whatley x
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Summary

Cerebrospinal fluid and serum were obtained from 16 clinically normal adult cows (11 dairy, 5 beef). Sodium, potassium, magnesium, total protein, and albumin concentrations, osmolality, and lactate dehydrogenase and creatine kinase activities, were quantified in csf and serum. Total and differential cell counting, protein electrophoresis, and IgG quantification were performed on csf. Statistical analyses of these variables, including mean, sem, range, and 95% confidence intervals, were performed. Effects of blood contamination were evaluated, and were found to be negligible for all measured constituents. Correction factors for csf creatine kinase and lactate dehydrogenase activities accounting for cellular contamination were developed.

Total nucleated cell count was similar to counts in csf of other species, but higher than values in healthy people. Differential leukocyte count in csf was similar to that reported in csf of other domestic animals: mostly lymphocytes, fewer monocytoid cells, and scant neutrophils.

Cerebrospinal fluid protein concentration was higher than concentration reported for dogs, goats, and people, but was similar to values reported for horses. Beef cows had higher csf total protein concentration than did dairy cows; also, beef cows had higher csf γ-globulin concentration.

The concentration of sodium in csf was slightly higher than the value in serum, and potassium concentration was lower than the value in serum. In contrast to studies of human beings, csf osmolality was generally less than serum osmolality in the cows studied. Reference values for csf electrolyte concentrations and osmolality are useful for diagnosis of salt poisoning and for assessment of the effects of fluid therapy. Magnesium concentration was lower in csf, compared with serum. Reference values may be useful for diagnosis of grass tetany.

Glucose concentration in csf was variable, compared with serum concentration; sometimes, it was similar, lower, or even higher than serum glucose concentration. This variation reflects a more complete equilibration of glucose between csf and blood, owing to the lower and more stable blood glucose concentration in cows.

Creatine kinase activity in csf was markedly less than, and was not correlated with, serum creatine kinase activity. Cerebrospinal fluid lactate dehydrogenase activity was markedly lower than serum lactate dehydrogenase activity. Compared with lactate dehydrogenase, creatine kinase activity had a wider range in these healthy cows; therefore, the former enzyme has higher specificity and sensitivity for diagnosis of diseases affecting the cns.

Free access
in American Journal of Veterinary Research

Summary

A commercially available automated enzyme-multiplied immunoassay technique (emit) was used to determine serum caffeine concentration after oral and iv administrations of caffeine at dosage of 5 mg/kg of body weight to 12 clinically normal dogs. Dogs were allotted to 2 groups of 6 dogs each; 1 group initially received caffeine orally and the other received caffeine iv. After 72 hours, caffeine administration was repeated in all dogs in the alternate manner. Serum samples were obtained at multiple intervals over 24 hours to determine distribution and elimination kinetics. Analysis of the drug concentration-time data indicated iv elimination half-life (t½) of 6.39 ± 1.87 hours, volume of distribution at steady state of 685.3 ± 132.2 ml/kg, total body clearance of 1.31 ± 0.38 ml/min/kg, absorption t½ of 1.02 ± 0.68 hour, oral elimination t½ of 6.53 ± 2.72 hours, lag time after oral administration of 0.0614 ± 0.0661 hour, highest measured concentration of 5.29 ± 1.17 μg/ml, time to peak concentration of 2.74 ± 1.30 hours, and bioavailability of 99.4 ± 19.4%. Data from 6 dogs best fit a 1-compartment open model and those from 6 other dogs best fit a 2-compartment open model. On the basis of data from the 6 dogs that best fit a 2-compartment model, t½ of distribution was 0.58 ± 0.72 hour. Data for oral administration best fit a single absorption phase and a single elimination phase.

The increased availability and simplicity of the emit offers an opportunity to study the application of caffeine elimination for clinical evaluation of dogs with liver disease. Data obtained from this study allow determination of t½ and clearance to be simplified by obtaining samples 4 and 8 hours after oral or iv administrations and establishes canine reference values for elimination kinetics of caffeine administered at dosage of 5 mg/kg and assayed by use of the emit.

Free access
in American Journal of Veterinary Research