Objective—To determine the effect of number of
blood samples and sampling times on plasma clearance
of technetium Tc 99m pentetate (Tc99mP) and
orthoiodohippurate sodium I 131(OIH).
Animals—20 dogs and 14 cats.
Procedure—Plasma clearances of OIH and Tc99mP
were calculated by use of a 2-compartment model, on
the basis of a 12-point curve as a reference method.
Plasma clearance was calculated by use of all possible
combinations of 4 to 11 samples. Time schedule yielding
the smallest difference from the reference method
was considered to be optimal. Regression analysis was
performed between the 12-point model and models
using a reduced number of samples.
Results—SD of the difference between the
12-point clearance and the models with reduced
numbers of samples increased when the number of
samples decreased. The SD of the difference
between 12-point clearance and 4-point clearance
was 4.17 ml/min for OIH and 0.94 ml/min for Tc99mP
in dogs and 0.45 ml/min for OIH and 0.11 ml/min for
Tc99mP in cats. Optimal schedules were distributed
logarithmically and included an early sample at 5 or
10 minutes, a late sample at 2.5, 3, 4, or 5 hours for
OIH, and a late sample at 4 or 5 hours for Tc99mP.
Conclusions and Clinical Relevance—Plasma clearances
of OIH and Tc99mP can be accurately calculated
in dogs and cats by use of a single-injection 2-compartment
pharmacologic model with a reduced number
of blood samples, resulting in an acceptable margin
of error. (Am J Vet Res 2000;61:280–285)
Objective—To compare the effects of propofol and
sevoflurane on the urethral pressure profile in female
Animals—10 healthy female dogs.
Procedure—Urethral pressure profilometry was performed
in awake dogs, during anesthesia with
sevoflurane at 1.5, 2.0, and 3.0% end-tidal concentration,
and during infusion of propofol at rates of 0.4,
0.8, and 1.2 mg/kg/min. A consistent plane of anesthesia
was maintained for each anesthetic protocol.
Maximum urethral pressure, maximum urethral closure
pressure, functional profile length, and functional
area were measured.
Results—Mean maximum urethral closure pressure
of awake dogs was not significantly different than that
of dogs anesthetized with propofol at all infusion
rates or with sevoflurane at 1.5 and 2.0% end-tidal
concentration. Functional area in awake dogs was significantly
higher than in anesthetized dogs. Functional
area of dogs during anesthesia with sevoflurane at
3.0% end-tidal concentration was significantly lower
than functional area for other anesthetic protocols.
Individual differences in the magnitude of effects of
propofol and sevoflurane on urethral pressures were
Conclusions and Clinical Relevance—Sevoflurane
is an alternative to propofol for anesthesia in female
dogs undergoing urethral pressure profilometry. Use
of these anesthetics at appropriate administration
rates should reliably distinguish normal from abnormal
maximum urethral closure pressures and functional
areas. Titration of anesthetic depth is a critical
component of urodynamic testing. (Am J Vet Res
Objective—To examine acid-base and hormonal abnormalities in dogs with diabetes mellitus.
Animals—48 dogs with diabetes mellitus and 17 healthy dogs.
Procedures—Blood was collected and serum ketone, glucose, lactate, electrolytes, insulin, glucagon, cortisol, epinephrine, norepinephrine, nonesterified fatty acid, and triglyceride concentrations were measured. Indicators of acid-base status were calculated and compared between groups.
Results—Serum ketone and glucose concentrations were significantly higher in diabetic than in healthy dogs, but there was no difference in venous blood pH or base excess between groups. Anion gap and strong ion difference were significantly higher and strong ion gap and serum bicarbonate concentration were significantly lower in the diabetic dogs. There were significant linear relationships between measures of acid-base status and serum ketone concentration, but not between measures of acid-base status and serum lactate concentration. Serum insulin concentration did not differ significantly between groups, but diabetic dogs had a wider range of values. All diabetic dogs with a serum ketone concentration > 1,000 μmol/L had a serum insulin concentration < 5 μU/mL. There were strong relationships between serum ketone concentration and serum glucagon-insulin ratio, serum cortisol concentration, and plasma norepinephrine concentration. Serum β-hydroxybutyrate concentration, expressed as a percentage of serum ketone concentration, decreased as serum ketone concentration increased.
Conclusions and Clinical Relevance—Results suggested that ketosis in diabetic dogs was related to the glucagon-insulin ratio with only low concentrations of insulin required to prevent ketosis. Acidosis in ketotic dogs was attributable largely to high serum ketone concentrations.
Objective—To determine maximum extrarenal plasma
clearance of technetium-99m-mercaptoacetyltriglycine
(99mTc–MAG3) and maximum extrarenal
hepatic uptake of 99mTc–MAG3 in cats.
Animals—6 clinically normal adult cats.
Procedure—Simultaneously, baseline plasma clearance
and camera-based uptake of 99mTc–MAG3 were
determined in anesthetized cats. Double exponential
curves were fitted to plasma clearance data. Injected
dose was divided by area under the curve and body
weight to determine 99mTc–MAG3 clearance. Regions
of interest were drawn around kidneys and liver, and
percentage dose uptake was determined 1 to 3 minutes
after injection. After bilateral nephrectomy,
simultaneous extrarenal plasma clearance and camera-
based hepatic uptake of 99mTc–MAG3 were evaluated
in each cat.
Results—Mean ± SD baseline plasma clearance and
extrarenal clearance were 5.29 ± 0.77 and 0.84 ± 0.47
mL/min/kg, respectively. Mean extrarenal clearance
(as a percentage of baseline plasma clearance) was
16.06 ± 7.64%. For right, left, and both kidneys, mean
percentage dose uptake was 9.42 ± 2.58, 9.37 ± 0.86,
and 18.79 ± 2.47%, respectively. Mean hepatic percentage
dose uptake before and after nephrectomy
was 12.95 ± 0.93 and 21.47 ± 2.00%, respectively.
Mean percentage change of hepatic uptake after
nephrectomy was 166.89 ± 23.19%.
Conclusions and Clinical Relevance—In cats,
extrarenal clearance of 99mTc–MAG3 is higher than that
of other species; therefore, 99mTc–MAG3 is not useful
for estimation of renal function in felids. Evaluation of
renal function in cats may be more accurate via camera-
based versus plasma clearance-based methods
because camera-based studies can discriminate specific
organs. (Am J Vet Res 2003;64:1076–1080)
Objective—To evaluate transurethral cystoscopy and
excretory urography for diagnosis of ectopic ureter in
female dogs and identify concurrent urogenital abnormalities.
Animals—25 female dogs.
Procedure—Medical records of female dogs that
underwent transurethral cystoscopy, excretory urography,
and ventral cystotomy were reviewed for signalment,
history, physical examination findings,
results of bacteriologic culture of urine, and surgical
findings. Videotapes of transurethral cystoscopy and
radiographic studies were reviewed systematically
without knowledge of surgical findings.
Results—Ectopic ureters were diagnosed in 24 of 25
(96%) of the dogs, bilaterally in 22 of 24 (91.6%) dogs.
Cystoscopic evaluation yielded a correct diagnosis in all
dogs when results of ventral cystotomy were used as
the diagnostic standard. Cystoscopic evaluation identified
a terminal ureteral opening for all ureters. Urethral
fenestrations, troughs, striping, and tenting were identified.
Abnormalities of the vestibule were identified in all
examinations available for review (24/25). The paramesonephric
septal remnant and its association with
ectopic ureters were identified and characterized by cystoscopy.
Radiographic findings were discordant with
surgical findings and correctly identified 36 of 46 (78.2%)
ectopic ureters and 2 of 4 normal ureters. Hydroureter
and renal abnormalities were associated with distal urethral
ectopic ureters on radiographic evaluations.
Conclusions and Clinical Relevance—Transurethral
cystoscopy was accurate and minimally invasive for identification
and classification of ectopic ureters in dogs.
Contrast radiography had limitations in diagnosis of
ectopic ureters. Cystoscopic findings and associated
vaginal and vestibular abnormalities support abnormal
embryologic development in the pathogenesis of ectopic
ureters. (J Am Vet Med Assoc 2003;223:475–481)