Objective—To determine concentrations of calcium
(total [tCa], ionized [iCa], protein-bound [pCa], and
complexed [cCa]) in dogs with chronic renal failure
Animals—23 dogs with CRF.
Procedure—Serum calcium was fractionated by use
of a micropartition system. Total calcium and iCa concentrations
and pH were measured in unfractionated
serum, and tCa concentration was measured in the
ultrafiltrate. The pCa fraction was calculated by subtracting
tCa of the ultrafiltrate from tCa concentration
of unfractionated serum. The iCa concentration in
unfractionated serum was subtracted from tCa concentration
in the ultrafiltrate to determine the concentration
Results—Concentrations of tCa, iCa, pCa, and cCa
had wide ranges among dogs with CRF. Dogs with
significantly low tCa concentration (7.70 ± 1.73 mg/dL)
had cCa concentration (0.76 ± 0.38 mg/dL) within reference
range, whereas dogs with reference range to
high tCa concentration (10.85 ± 1.13 mg/dL) had significantly
high cCa concentration (2.62 ± 1.04 mg/dL).
There was no significant difference in iCa or pCa concentrations
Conclusions and Clinical Relevance—Concentrations
of tCa, iCa, cCa, and pCa varied widely in
dogs with CRF. Overall, cCa concentration was high,
although subpopulations differed in cCa and tCa concentrations.
Differences in tCa concentration were
primarily attributable to differences in cCa fraction.
(Am J Vet Res 2003;64:1181–1184)
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)
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)
Case Description—A 6-month-old female domestic shorthair cat was admitted for evaluation of intermittent clinical signs of hematuria and inappropriate urination for the past 2 months.
Clinical Findings—Transabdominal ultrasonography revealed a multilayered mass in the urinary bladder apex consistent with full-thickness invagination of the bladder wall.
Treatment and Outcome—Exploratory surgery was performed, and partial inversion of the urinary bladder was confirmed. The invaginated bladder apex was manually reduced, and partial cystectomy was performed to remove the invaginated section of bladder wall. Histologic findings were consistent with vascular congestion and edema secondary to partial invagination. Bacterial culture of a section of the bladder mucosa demonstrated concurrent bacterial urinary tract infection. Clinical signs resolved following surgical resection of the bladder apex and antimicrobial treatment for the concurrent urinary tract infection.
Clinical Relevance—Partial invagination of the urinary bladder should be considered in the differential diagnosis for cats with clinical signs of hematuria, stranguria, and inappropriate urination. A diagnosis may be made on the basis of detection of invaginated tissue in the bladder apex during abdominal ultrasonography.
Objective—To clone and sequence the cDNA for
feline preproparathyroid hormone (preproPTH) and to
compare that sequence with other known parathyroid
hormone (PTH) sequences.
Sample Population—Parathyroid glands from 1
Procedure—A cDNA library was constructed in λ
phage from feline parathyroid gland mRNA and
screened with a radiolabeled canine PTH probe.
Positive clones were sequenced, and nucleic acid and
deduced amino acid sequences were analyzed and
compared with known preproPTH and PTH
Result—Screening of approximately 2 X 105 recombinant
plaques revealed 3 that hybridized with the
canine PTH probe; 2 clones comprised the complete
sequence for feline preproPTH. Feline preproPTH
cDNA consisted of a 63-base pair (bp) 5'-untranslated
region (UTR), a 348-bp coding region, and a 326-bp 3'-UTR. The coding region encoded a 115-amino acid
peptide. Mature feline PTH consisted of 84 amino
acids. Amino acid sequence analysis revealed that
feline PTH was > 83% identical to canine, bovine,
swine, equine, human, and macaque PTH and 69, 71,
and 44% identical to mouse, rat, and chicken PTH,
respectively. Within the region responsible for hormonal
activity (amino acids 1 to 34), feline PTH was >
79% identical to other mammalian PTH sequences
and 64% identical to the chicken sequence.
Conclusions and Clinical Relevance—The amino
acid sequence of PTH is conserved among mammalian
species. Knowledge of the cDNA sequence
for feline PTH may be useful to investigate disturbances
of calcium metabolism and alterations in PTH
expression in cats. (Am J Vet Res 2002;63:194–197)
Objective—To evaluate calcium balance and parathyroid
gland function in healthy horses and horses with
enterocolitis and compare results of an immunochemiluminometric
assay (ICMA) with those of an
immunoradiometric assay (IRMA) for determination of
serum intact parathyroid hormone (PTH) concentrations
Animals—64 horses with enterocolitis and 62 healthy
Procedures—Blood and urine samples were collected
for determination of serum total calcium, ionized calcium
(Ca2+) and magnesium (Mg2+), phosphorus, BUN,
total protein, creatinine, albumin, and PTH concentrations,
venous blood gases, and fractional urinary clearance
of calcium (FCa) and phosphorus (FP). Serum
concentrations of PTH were measured in 40 horses by
use of both the IRMA and ICMA.
Results—Most (48/64; 75%) horses with enterocolitis
had decreased serum total calcium, Ca2+, and Mg2+
concentrations and increased phosphorus concentrations,
compared with healthy horses. Serum PTH concentration
was increased in most (36/51; 70.6%) horses
with hypocalcemia. In addition, FCa was significantly
decreased and FP significantly increased in
horses with enterocolitis, compared with healthy horses.
Results of ICMA were in agreement with results of
Conclusions and Clinical Relevance—Enterocolitis
in horses is often associated with hypocalcemia;
79.7% of affected horses had ionized hypocalcemia.
Because FCa was low, it is unlikely that renal calcium
loss was the cause of hypocalcemia. Serum PTH concentrations
varied in horses with enterocolitis and concomitant
hypocalcemia. However, we believe low PTH
concentration in some hypocalcemic horses may be
the result of impaired parathyroid gland function. ( Am
J Vet Res 2001;62:938–947)
Objective—To determine efficacy of a protocol for managing urethral obstruction (UO) in male cats without urethral catheterization.
Animals—15 male cats with UO in which conventional treatment had been declined.
Procedures—Laboratory testing and abdominal radiography were performed, and cats with severe metabolic derangements or urinary calculi were excluded. Treatment included administration of acepromazine (0.25 mg, IM, or 2.5 mg, PO, q 8 h), buprenorphine (0.075 mg, PO, q 8 h), and medetomidine (0.1 mg, IM, q 24 h) and decompressive cystocentesis and SC administration of fluids as needed. Cats were placed in a quiet, dark environment to minimize stress. Treatment success was defined as spontaneous urination within 72 hours and subsequent discharge from the hospital.
Results—Treatment was successful in 11 of the 15 cats. In the remaining 4 cats, treatment was considered to have failed because of development of uroabdomen (n = 3) or hemoabdomen (1). Cats in which treatment failed had significantly higher serum creatinine concentrations than did cats in which treatment was successful. Necropsy was performed on 3 cats in which treatment had failed. All 3 had severe inflammatory disease of the urinary bladder, but none had evidence of bladder rupture.
Conclusions and Clinical Relevance—Results suggested that in male cats, a combination of pharmacological treatment, decompressive cystocentesis, and a low-stress environment may allow for resolution of UO without the need for urethral catheterization. This low-cost protocol could serve as an alternative to euthanasia when financial constraints prevent more extensive treatment.
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