Objective—To evaluate the effect of infection with bovine respiratory syncytial virus (BRSV) on clearance of inhaled antigens from the lungs of calves.
Animals—Eleven 6- to 8-week-old Holstein bull calves.
Procedures—Aerosolized 99mtechnetium (99mTc)-labeled diethylene triamine pentacetate (DTPA; 3 calves), commonly used to measure integrity of the pulmonary epithelium, and 99mTc-labeled ovalbumin (OA; 8 calves), commonly used as a prototype allergen, were used to evaluate pulmonary clearance before, during, and after experimentally induced infection with BRSV or sham inoculation with BRSV. Uptake in plasma (6 calves) and lung-efferent lymph (1 calf) was examined.
Results—Clearance of 99mTc-DTPA was significantly increased during BRSV infection; clearance of 99mTc-OA was decreased on day 7 after inoculation. Clearance time was correlated with severity of clinical disease, and amounts of 99mTc-OA in plasma and lymph were inversely correlated with clearance time. Minimum amounts of 99mTc-OA were detected at time points when pulmonary clearance of 99mTc-OA was most delayed.
Conclusions and Clinical Relevance—BRSV caused infection of the respiratory tract with peak signs of clinical disease at 7 or 8 days after inoculation. Concurrently, there was a diminished ability to move inhaled protein antigen out of the lungs. Prolonged exposure to inhaled antigens during BRSV infection may enhance antigen presentation with consequent allergic sensitization and development of chronic inflammatory lung disease.
Impact for Human Medicine—Infection of humans with respiratory syncytial virus early after birth is associated with subsequent development of allergic asthma. Results for BRSV infection in these calves suggested a supportive mechanism for this scenario.
Objective—To define the reference range for laminar blood flow (BF) and vascular permeability (VPM) in horses without laminitis by use of dynamic contrast-enhanced computed tomography (CT).
Animals—9 adult horses that were not lame and had no abnormalities of the laminae or phalanges detectable via radiographic examination.
Procedures—Each horse was anesthetized by use of a routine protocol. Horses were placed in right or left lateral recumbency with the dependent forelimb in the CT gantry; only 1 limb of each horse was scanned. Serial 10-mm collimated transverse CT images were acquired at the same location every other second for 90 seconds during infusion of ionic, iodinated contrast medium. Custom software was used to estimate BF, VPM, and fractional vascular volume (FVV) in the dorsal, dorsomedial, and dorsolateral laminar regions.
Results—Among the 9 horses' forelimbs, mean ± SD dorsal laminar BF was 0.43 ± 0.21 mL•min−1•mL−1. Mean dorsomedial and dorsolateral laminar BFs were 0.26 ± 0.16 mL•min−1•mL−1 and 0.24 ± 0.16 mL•min−1•mL−1, respectively. Mean dorsal laminar VPM was 0.09 ± 0.03 mL•min−1•mL−1. Mean dorsomedial and dorsolateral laminar VPMs were 0.16 ± 0.06 mL•min−1•mL−1 and 0.12 ± 0.06 mL•min−1•mL−1, respectively. Mean dorsal laminar FVV was 0.63 ± 0.20 and dorsomedial and dorsolateral laminar FVV were 0.37 ± 0.14 and 0.34 ± 0.17, respectively.
Conclusions and Clinical Relevance—In horses, laminar BF, VPM, and FVV can be non-invasively measured by use of dynamic contrast-enhanced CT.
Objective—To provide a detailed description of the
vascular anatomy of the distal portion of the forelimbs
of horses by use of computed tomography angiography
Sample Population—6 forelimbs of 5 horses and 1
forelimb from an equine cadaver; none of the horses
had orthopedic or vascular disease.
Procedure—Horses were anesthetized and CTA was
conducted on the dependent forelimb. A catheter
was inserted in the median artery, and contrast medium
was infused at a rate of 3 mL/s. A computed
tomography (CT) scanner was used to obtain contiguous
slices from the region of the proximal sesamoid
bones to the toe. All horses were allowed to recover
from anesthesia. To help identify vessel patterns in
the distal portion of the forelimb, the median artery
and lateral palmar digital vein of a heparinized forelimb
obtained from an equine cadaver were infused
with red and blue polymethylmethacrylate and the
distal portion of that forelimb was then sectioned to
correspond to CTA images.
Results—Vessel patterns in CTA images matched
vascular anatomic structures of the cadaver forelimb
and were consistent with published anatomic structures.
Major and minor vessels were consistently visible
in CTA images of all horses. There were no complications
reported in any horses.
Conclusions and Clinical Relevance—Use of CTA
provided a highly detailed depiction of the vasculature
of the distal portion of the equine forelimb. This was
a safe technique and should be useful in the evaluation
of the blood supply to the distal portion of the
forelimb. (Am J Vet Res 2004;65:1409–1420)
Objective—To characterize a genetic component to
cricopharyngeal dysfunction (CD) in Golden Retrievers.
Procedure—The CD phenotype was determined by
videofluoroscopy, and dogs were classified as affected
if the upper esophageal sphincter (UES) did not open,
if there were morphologic abnormalities of the UES, or
if opening of the UES was delayed for ≥ 6 videofluoroscopic
frames (0.2 seconds) after closure of the
epiglottis. All survey radiographic and videofluoroscopic
studies were reviewed by the same radiologist.
Results—Of the 117 dogs (47 males and 70 females)
with a CD phenotype determined via videofluoroscopy,
21 dogs (18.0%) had abnormalities of the
UES (affected). Of these 21 dogs, 9 were males
(19.1% of all males) and 12 were females (17.1% of all
females). The heritability of CD in a threshold model
was estimated as 0.61, which established that CD
could be passed from parent to offspring. Results of
complex segregation analysis suggested that a single
recessive allele of large effect contributed to the
expression of this disease in Golden Retrievers.
Conclusions and Clinical Relevance—The determination
that CD is inherited in Golden Retrievers is an
important step in providing information for veterinarians
attending dogs with this disorder. Breeders also
require this information to make informed breeding
decisions. ( Am J Vet Res 2004;65:344–349)
Objective—To determine efficacy and safety of percutaneous
radiofrequency heat ablation for treatment
of hyperthyroidism in cats.
Procedure—Hyperthyroidism was diagnosed via clinical
signs and high serum total (TT4) and free thyroxine
(fT4) concentrations. One or 2 hyperfunctional cervical
thyroid nodules were detected by use of scintigraphy
and ultrasonography. If cats had 1 abnormal thyroid
lobe, heat ablation was performed on that lobe; if
cats had 2 abnormal lobes, heat ablation was applied
to the larger lobe. Overall, heat ablation was performed
14 times in the 9 cats. Clinical signs and
serum TT4, fT4, and calcium concentrations were
monitored daily for 2 days after the procedure, weekly
for the first month, and then monthly. Laryngeal
function was evaluated and cervical ultrasonography
and thyroid scintigraphy were also performed.
Monitoring continued for as long as 9 months after
heat ablation if a cat became euthyroid or until an
owner chose an alternative treatment because of
recurrence of hyperthyroidism.
Results—Serum TT4 and fT4 concentrations transiently
decreased after all 14 heat ablation procedures (≤
reference range after 10 of 14 treatments) within 2
days after the procedure. Cats were euthyroid for 0 to
18 months (mean, 4 months). Hyperthyroidism
recurred in all cats. Adverse effects included transient
Horner's syndrome (2 cats) and laryngeal paralysis
without clinical signs (1 cat).
Conclusions and Clinical Relevance—Percutaneous
heat ablation as a treatment for hyperthyroidism in cats
is effective transiently but not permanently. (J Am Vet
Med Assoc 2003;223:1602–1607)
Objective—To evaluate the efficacy and safety of
ultrasonographically guided radiofrequency heat ablation
of parathyroid masses in dogs with primary
Procedure—In all dogs, either 1 or 2 parathyroid
masses were evident ultrasonographically. Dogs
were anesthetized, and a 20-gauge over-the-needle
catheter was directed into the parathyroid mass via
ultrasonographic guidance. Radiofrequency heat
was applied to the stylet of the catheter until there
was sonographically apparent change to the entire
parenchyma of the mass. Serum total and ionized
calcium and parathyroid hormone concentrations
were monitored daily for 5 days after the ablation
procedure and again at 1, 2, and 3-month intervals,
if possible. Dogs were monitored for adverse
Results—One treatment was required in 6 dogs, 2
treatments were required in 2 dogs, and treatment
was unsuccessful in 3 dogs. Serum total and ionized
calcium concentrations were within reference ranges
within 2 days of the last procedure in all 8 successfully
treated dogs. Serum parathyroid hormone concentration
was decreased 24 hours after treatment in
all 8 dogs. Hypocalcemia developed in 5 of the 8 successfully
treated dogs, all of which required treatment.
One dog had a transient voice change. Other
adverse effects were not reported.
Conclusions and Clinical Relevance—Ultrasonographically
guided radiofrequency heat ablation of
parathyroid masses is a safe and effective alternative
to surgery in dogs with primary hyperparathyroidism.
(J Am Vet Med Assoc 2001;218:1106–1110)
Objective—To compare radiographic and arthroscopic
abnormalities in juvenile dogs with clinically apparent
Animals—52 dogs (70 hip joints) with clinical signs of hip
dysplasia scheduled to undergo triple pelvic osteotomy.
Procedure—A ventrodorsal radiographic projection of
the pelvis was evaluated by a radiologist unaware of
clinical and arthroscopic findings, and radiographic
osteoarthritic abnormalities were judged and scored
as absent (0), mild (1), moderate (2), or severe (3).
Arthroscopy was performed by a surgeon unaware of
clinical and radiographic findings, and arthroscopic
abnormalities were graded from 0 (normal) to 5
(exposed, eburnated subchondral bone).
Results—In 30 of the 70 (43%) hip joints, no radiographic
osteoarthritic abnormalities were seen.
Severe, full-thickness articular cartilage lesions
(grade 4) of the femoral head or acetabulum were
seen arthroscopically in 14 (20%) joints. Lesions ≥
grade 2 were seen in 60 (86%) joints. Partial tearing
of the ligament of the femoral head was present
in 57 (81%) joints, and complete rupture was
seen in 5 (7%). Radiographic abnormalities were
seen in 13 of the 14 (93%; 95% confidence interval,
66% to 99.8%) joints with grade 4 arthroscopic
abnormalities but in only 23 of the 46 (50%; 95%
confidence interval, 35% to 65%) joints with grade
2 or 3 arthroscopic abnormalities.
Conclusions and Clinical Relevance—Results suggest
that radiography is not a sensitive method for identifying
moderate cartilage lesions in juvenile dogs with hip dysplasia.
If moderate cartilage lesions are an important
prognostic indicator for the success of triple pelvic
osteotomy, then methods other than radiography should
be used to detect these lesions. (J Am Vet Med Assoc 2005;227:1091–1094)
Procedure—Results of dynamic portoscintigraphic
studies were reviewed by 4 radiologists without
knowledge of signalment, history, or medical profile.
Results were judged to be negative or positive on the
basis of the dynamic scan. Composite images were
formulated, and hand-drawn regions of interest were
determined for the heart and liver. Time-activity
curves were generated, time-zero points were selected,
curves were integrated during a 10-second interval,
and shunt fractions were calculated.
Results—Radiologists were in agreement regarding
positive versus negative results for 99 of 101 studies.
Interoperator variance in shunt fraction calculation
ranged from 0.4 to 59.6%. For 51 studies with positive
results, variance ranged from 2.5 to 59.6% (mean
± SD, 22.8 ± 14.5%); differences among reviewers
were significant. For 48 studies with negative results,
variance in shunt fraction ranged from 0.4 to 25.9%
(mean, 5.3 ± 5.8%); significant differences among
reviewers were not detected. Shunt fraction calculations
were not exactly reproducible among radiologists
in 94 and 100% of studies with negative or positive
Conclusions and Clinical Relevance—Results suggest
that shunt fraction values are not reproducible
among operators. Range in variability was greater in
studies with positive results. This factor may be of
particular clinical importance in reassessment of
patients after incomplete shunt ligation. (J Am Vet
Med Assoc 2001;218:1116–1119)
Objective—To determine the efficacy and safety of
percutaneous ethanol injection (PEI) for the treatment
of hyperthyroidism caused by bilateral hyperplastic
thyroid nodules in cats.
Procedure—Hyperthyroidism was diagnosed on the
basis of clinical signs and increased serum total thyroxine
(TT4) concentrations. The presence of 2 cervical
thyroid nodules was confirmed by use of ultrasonography
and technetium Tc 99m albumin thyroid scans.
After the death of 1 cat that received PEI in both thyroid
nodules at the same time, the protocol was
changed to injecting ethanol into 1 nodule at a time,
with at least 1 month between injections. Clinical
signs, serum TT4 concentrations, serum ionized calcium
concentrations, laryngeal function, findings on
ultrasonographic examinations of the ventral cervical
region, and results of thyroid scans were monitored.
Results—Serum TT4 concentrations transiently
decreased in all 6 cats (into the reference range in 5 of
6 cats) within 4 days of the first staged ethanol injection.
Each subsequent injection resulted in a transient
decrease in serum TT4 concentration. The longest period
of euthyroidism was 27 weeks. Adverse effects
included Horner's syndrome, dysphonia, and laryngeal
paralysis. One cat died of unrelated causes. One cat
underwent bilateral thyroidectomy, 2 cats were treated
with methimazole, and 2 cats that had increased
serum TT4 concentrations were not treated further,
because they remained clinically normal.
Conclusions and Clinical Relevance—Percutaneous
ethanol ablation of bilateral thyroid nodules as a treatment
for cats with hyperthyroidism is not recommended.
This treatment is not as efficacious as the
medical and surgical treatments presently used.
(J Am Vet Med Assoc 2001;218:1293–1297)