Objective—To establish a sensitive test for the detection of autoantibodies against thyroid peroxidase (TPO) in canine serum samples.
Sample Population—365 serum samples from dogs with hypothyroidism as determined on the basis of serum concentrations of total and free triiodothyronine (T3), total and free thyroxine (T4), and thyroidstimulating hormone, of which 195 (53%) had positive results for at least 1 of 3 thyroid autoantibodies (against thyroglobulin [Tg], T4, or T3) and serum samples from 28 healthy dogs (control samples).
Procedure—TPO was purified from canine thyroid glands by extraction with detergents, ultracentrifugation, and precipitation with ammonium sulfate. Screening for anti-TPO autoantibodies in canine sera was performed by use of an immunoblot assay. Thyroid extract containing TPO was separated electrophoretically, blotted, and probed with canine sera. Alkaline phosphatase–conjugated rabbit anti-dog IgG was used for detection of bound antibodies.
Results—TPO bands were observed at 110, 100, and 40 kd. Anti-TPO autoantibodies against the 40-kd fragment were detected in 33 (17%) sera of dogs with positive results for anti-Tg, anti-T4, or anti-T3 autoantibodies but not in sera of hypothyroid dogs without these autoantibodies or in sera of healthy dogs.
Conclusions and Clinical Relevance—The immunoblot assay was a sensitive and specific method for the detection of autoantibodies because it also provided information about the antigen. Anti-TPO autoantibodies were clearly detected in a fraction of hypothyroid dogs. The value of anti-TPO autoantibodies for use in early diagnosis of animals with thyroid gland diseases should be evaluated in additional studies.
Objective—To assess associations between epidemiologic
and laboratory variables and calciotropic
hormones in cats with odontoclastic resorptive
Animals—182 client-owned cats older than 1 year of
age with oral disease.
Procedure—Information on medical history, behavior,
living environment, and feeding management was
assessed by use of a questionnaire. After induction of
general anesthesia, oral examination was performed
following standardized protocols and included dental
probing and full-mouth radiography. Laboratory analyses
included evaluation of FeLV-FIV status, serum biochemical
analyses, CBC, urinalysis, and serum concentrations
of intact parathyroid hormone (iPTH),
parathyroid hormone-related peptide (PTHrP), 25-hydroxyvitamin D (25-OHD), free thyroxine (fT4), and
ionized calcium (iCa).
Results—ORLs were identified in 72.5% of cats.
Mandibular third premolars were the most commonly
affected teeth. Cats with ORLs were significantly
older (mean, 9.2 years) than cats without ORLs
(mean, 6.6 years). Multivariate logistic regression
analysis revealed that 25-OHD, urine specific gravity,
jaw-opening reflex on probing, and missing teeth
were significant variables, even after accounting for
age. Cats with ORLs had significantly higher mean
serum concentration of 25-OHD (112.4 nmol/L) and
significantly lower mean urine specific gravity
(1.0263), compared with cats without ORLs (89.8
nmol/L and 1.0366, respectively).
Conclusions and Clinical Relevance—Results did
not indicate associations between iPTH, PTHrP, or fT4
and development of ORLs. In affected cats, the
importance of high serum 25-OHD and low urine specific
gravity has not been determined. (Am J Vet Res 2005;66:1446–1452)
Objective—To determine whether pamidronate disodium
can reduce cholecalciferol-induced toxicosis
in a dose-related manner.
Animals—20 clinically normal, 8- to 12-month-old
Procedure—All dogs were given 8 mg of cholecalciferol
(CCF)/kg of body weight once orally, then were randomly
assigned to 4 groups of 5 dogs each. Dogs were treated
with IV administration of 0.9% NaCl solution (SC
group), 0.65 mg of pamidronate/kg in 0.9% NaCl solution
(LP group), 1.3 mg of pamidronate/kg in
0.9% NaCl solution (MP group), or 2.0 mg of
pamidronate/kg in 0.9% NaCl solution (HP group) on
days 1 and 4 after administration of CCF. Dogs were
observed for 14 days, and serial blood samples were collected
for serum biochemical, electrolyte, and 25-hydroxyvitamin
D3 analyses. Urine samples were collected for
determination of specific gravity. Glomerular filtration rate
(GFR) was determined by plasma iohexol clearance.
Histologic examination of renal tissue was performed.
Results—One dog in the SC group was euthanatized 3
days after administration of CCF because of severe clinical
signs of toxicosis. Dogs in the HP group had significantly
higher mean GFR (day 3), serum potassium concentrations
(day 14), and urine specific gravity (days 7
and 14) and significantly lower mean serum creatinine
concentrations and total calcium × phosphorus concentration
product (days 4 and 7) than dogs in the SC
group. Dogs in the HP group had no abnormal findings
on histologic examination of renal tissue, dogs in the LP
and MP groups had trace to mild mineralization of renal
tissue, and dogs in the SC group had moderate mineralization
and cellular necrosis of proximal renal tubules.
Conclusions and Clinical Relevance—Pamidronate
disodium is a potentially useful drug to reduce CCFinduced
toxicosis and other causes of hypercalcemia
associated with increased bone resorption in dogs.
(Am J Vet Res 2000;61:9–13)
Objectives—To determine the effects of racing and
training on serum thyroxine (T4), triiodothyronine (T3),
and thyroid stimulating hormone (TSH) concentrations
Animals—9 adult racing Greyhounds.
Procedure—Serum thyroid hormone concentrations
were measured before and 5 minutes after a race in
dogs trained to race 500m twice weekly for 6 months.
Resting concentrations were measured again when
these dogs had been neutered and had not raced for
3 months. Postrace concentrations were adjusted relative
to albumin concentration to allow for effects of
hemoconcentration. Thyroid hormone concentrations
were then compared with those of clinically normal
dogs of non-Greyhound breeds.
Results—When adjusted for hemoconcentration,
total T4 concentrations increased significantly after
racing and TSH concentrations decreased; however,
there was no evidence of a change in free T4 or total
or free T3 concentrations. Resting total T4 concentrations
increased significantly when dogs had been
neutered and were not in training. There was no evidence
that training and neutering affected resting
TSH, total or free T3, or free T4 concentrations.
Resting concentrations of T3, TSH, and autoantibodies
against T4, T3, and thyroglobulin were similar to those
found in other breeds; however, resting free and total
T4 concentrations were lower than those found in
Conclusions and Clinical Relevance—Except for
total T4, thyroid hormone concentrations in
Greyhounds are affected little by sprint racing and
training. Greyhounds with low resting total and free T4
concentrations may not be hypothyroid. (Am J Vet