Objective—To describe the kinetics of demethylation
of 13C-aminopyrine in healthy dogs for use in determining
the most appropriate time for collection of
blood samples for a 13C-aminopyrine demethylation
blood test for evaluation of hepatic function.
Animals—9 healthy dogs.
Procedures—A 2-mL baseline blood sample was collected
into an evacuated heparinized tube, and 13Caminopyrine
was administered to each dog (2 mg/kg,
IV). Additional 2-mL blood samples were collected 15,
30, 45, 60, 75, 90, 105, 120, 135, 150, 180, 240, 300,
and 360 minutes after 13C-aminopyrine administration.
The CO2 was extracted from blood samples by addition
of a strong acid, and the percentage dose of
13CO2 (PCD) in the extracted gas was determined by
fractional mass spectrometry.
Results—No dogs had gross evidence of adverse
effects, and all had an increase in PCD after IV administration
of 13C-aminopyrine. The PCD had the least
variability among 5 variables used to evaluate hepatic
demethylating capacity. Peak PCD was detected at 30
minutes in 1 dog, 45 minutes in 5 dogs, 60 minutes
in 2 dogs, and 75 minutes in 1 dog. The mean PCD for
the 9 dogs peaked at 45 minutes after 13C-aminopyrine
Conclusions and Clinical Relevance—PCD appears
to be the preferable variable for evaluation of hepatic
demethylating capacity. Intravenous administration of
13C-aminopyrine leads to a consistent increase in PCD.
Mean PCD peaked 45 minutes after administration,
suggesting that blood sample collection 45 minutes
after 13C-aminopyrine administration may be appropriate
for use in estimating hepatic demethylating
capacity. (Am J Vet Res 2004;65:159–162)
Objective—To determine an optimal dose of carbon 13 (13C)-labeled aminopyrine for use in a 13C-aminopyrine demethylation blood test in healthy dogs.
Animals—9 adult dogs.
Procedures—Food was withheld from each dog for 12 hours. A 2-mL baseline blood sample was obtained from each dog and placed into an evacuated tube containing sodium heparin. Carbon 13-labeled aminopyrine was administered IV at doses of 1, 2, 5, or 10 mg/kg. Additional blood samples (2 mL) were obtained and placed into evacuated tubes containing sodium heparin 30, 45, 60, and 75 minutes after 13C-aminopyrine administration. Hydrochloric acid was used to extract CO2 from blood samples. The extracted gas was analyzed by fractional mass spectrometry to determine the percentage dose of 13C administered as 13C-aminopyrine and recovered in extracted gas (PCD).
Results—Gross evidence of clinical adverse effects was not detected in any dog after administration of 13C-aminopyrine. The mean coefficient of variation (CV) for PCD was significantly lower than the mean CV for the summation of PCD values up to a given sampling time (CUMPCD). Mean PCD values among the 4 doses for each sample time were not significantly different. Administration of 13C-aminopyrine at a dose of 2 mg/kg resulted in the lowest interindividual variability.
Conclusions and Clinical Relevance—The PCD is superior to CUMPCD for the quantification of aminopyrine demethylation. Administration of 13C-13C-aminopyrine at a dose of 2 mg/kg is appropriate for use in the 13C-aminopyrine demethylation blood test in healthy dogs.
Objective—To assess the heritability of pancreatic
acinar atrophy (PAA) in German Shepherd Dogs
(GSDs) in the United States.
Animals—135 GSDs belonging to 2 multigenerational
Procedure—Two multigenerational pedigrees of
GSDs with family members with PAA were identified.
The clinical history of each GSD enrolled in the study
was recorded, and serum samples for canine trypsinlike
immunoreactivity (cTLI) analysis were collected
from 102 dogs. Dogs with a serum cTLI concentration
≤ 2.0 µg/L were considered to have exocrine pancreatic
insufficiency (EPI) and were assumed to have
Results—Pedigree I consisted of 59 dogs and pedigree
II of 76 dogs. Serum cTLI concentrations were
measured in 48 dogs from pedigree I and 54 dogs
from pedigree II. A total of 19 dogs (14.1%) were
determined to have EPI, 9 in pedigree I (15.3%) and
10 in pedigree II (13.6%). Of the 19 dogs with EPI, 8
were male and 11 were female.
Conclusion and Clinical Relevance—Evaluation
of data by complex segregation analysis is strongly
suggestive of an autosomal recessive mode of
inheritance for EPI in GSDs in the United States.
(Am J Vet Res 2002;63:1429–1434)