Objectives—To evaluate computed tomography (CT)
densitometry as a technique for quantifying contrast
enhancement of compressive soft tissues in the
canine lumbosacral vertebral canal and to determine
whether the degree of contrast enhancement can be
used to help predict tissue type or histopathologic characteristics.
Animals—29 large breed dogs with lumbosacral
Procedure—Contrast-enhanced CT of L5-S3 was performed
by use of a previously described protocol. At
each disk level, CT densities of a water-filled syringe,
epaxial muscles, and 4 vertebral canal locations were
measured. Mean tissue enhancement was calculated
by vertebral canal location, using water-filled syringe
enhancement as a correction factor. Corrected CT
enhancement was compared with tissue type,
degree of tissue inflammation, and degree of tissue
Results—Intravenous contrast administration of contrast
medium significantly increased CT densities of
water-filled syringes and epaxial muscles. Corrected CT
enhancement of vertebral canal soft tissues at stenotic
sites was greater than at nonstenotic sites. There was
no association between enhancement and tissue type
for any vertebral canal location. There was no correlation
between enhancement and degree of tissue inflammation.
There was a correlation between enhancement
and tissue activity in the dorsal vertebral canal only.
Conclusions and Clinical Relevance—A water-filled
syringe is a useful calibration tool for CT density measurements.
The degree of tissue contrast enhancement,
measured by CT densitometry, can be helpful for
predicting the location of compressive soft tissues in
dogs with lumbosacral stenosis. However, it is of limited
value for predicting compressive soft-tissue types or
histopathologic characteristics. (Am J Vet Res
To determine whether palmar digital nerve (PDN) blockade in horses with a combination of dexmedetomidine and mepivacaine would block the response to mechanical force applied to the digit longer than would anesthetizing these nerves with mepivacaine alone or dexmedetomidine alone.
8 mares with no signs of lameness.
In a randomized, crossover, blinded, experimental study, both PDNs of the same forelimb of each horse were anesthetized by perineural injection with either 30 mg mepivacaine alone, 250 µg of dexmedetomidine alone, or 30 mg mepivacaine combined with 250 µg of dexmedetomidine. Each horse received each treatment, and treatments were administered ≥ 2 weeks apart. The mechanical nociceptive threshold was measured at a region between the heel bulbs with the use of a digital force gauge before (baseline) and at 15-minute intervals after treatment.
The mean duration of sensory blockade of the digit was 2-fold longer when a combination of mepivacaine and dexmedetomidine was administered (371 minutes), compared with when mepivacaine alone was administered (186 minutes). Treatment with dexmedetomidine alone did not change the mechanical nociceptive threshold substantially from baseline and resulted in no clinical signs of sedation.
Results indicated that relief from digital pain provided by perineural treatment with mepivacaine for PDN blockade can be extended by adding dexmedetomidine to the injectate.
Objective—To evaluate the safety and efficacy of a vaccine containing plasmid DNA with an insert encoding human tyrosinase (ie, huTyr vaccine) as adjunctive treatment for oral malignant melanoma (MM) in dogs.
Animals—111 dogs (58 prospectively enrolled in a multicenter clinical trial and 53 historical controls) with stage II or III oral MM (modified World Health Organization staging scale, I to IV) in which locoregional disease control was achieved.
Procedures—58 dogs received an initial series of 4 injections of huTyr vaccine (102 μg of DNA/injection) administered transdermally by use of a needle-free IM vaccination device. Dogs were monitored for adverse reactions. Surviving dogs received booster injections at 6-month intervals thereafter. Survival time for vaccinates was compared with that of historical control dogs via Kaplan-Meier survival analysis for the outcome of death.
Results—Kaplan-Meier analysis of survival time until death attributable to MM was determined to be significantly improved for dogs that received the huTyr vaccine, compared with that of historical controls. However, median survival time could not be determined for vaccinates because < 50% died of MM before the end of the observation period. No systemic reactions requiring veterinary intervention were associated with vaccination. Local reactions were primarily limited to acute wheal or hematoma formation, mild signs of pain at the injection site, and postvaccination bruising.
Conclusions and Clinical Relevance—Results support the safety and efficacy of the huTyr DNA vaccine in dogs as adjunctive treatment for oral MM.
Impact for Human Medicine—Response to DNA vaccination in dogs with oral MM may be useful in development of plasmid DNA vaccination protocols for human patients with similar disease.