Search Results

Abstract

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.

Abstract

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.

Abstract

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 (CTA).

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)

Abstract

Objective—To characterize a genetic component to cricopharyngeal dysfunction (CD) in Golden Retrievers.

Animals—117 dogs.

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)

Abstract

Objective—To determine efficacy and safety of percutaneous radiofrequency heat ablation for treatment of hyperthyroidism in cats.

Design—Prospective study.

Animals—9 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)

Abstract

Objective—To evaluate the efficacy and safety of ultrasonographically guided radiofrequency heat ablation of parathyroid masses in dogs with primary hyperparathyroidism.

Design—Clinical trial.

Animals—11 dogs.

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 effects.

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)

Abstract

Objective—To compare radiographic and arthroscopic abnormalities in juvenile dogs with clinically apparent hip dysplasia.

Design—Case series.

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)

Abstract

Objective—To determine interoperator variance in shunt fraction calculation.

Design—Case series.

Sample Population—101 transrectal portoscintigraphic studies.

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 results, respectively.

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)

Abstract

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.

Design—Prospective study.

Animals—7 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)