To evaluate the safety of oral administration of a d-ribose-l-cysteine (RibCys) supplement to dogs and the effect of this supplementation on erythrocyte glutathione (GSH) concentration.
24 healthy adult dogs.
In a randomized, double-blinded, controlled trial, dogs received 500 mg of a RibCys supplement or placebo (n = 12/group), PO, every 12 hours for 4 weeks. Dogs were evaluated weekly by means of a physical examination, CBC, serum biochemical analysis, urinalysis, and owner-completed quality-of-life questionnaire. Erythrocyte GSH concentration was measured on day 0 (ie, the day before treatment began) and weekly during supplementation.
No dose-limiting adverse effects were noted in any dog. Two dogs in each group had mild, self-limiting diarrhea and anemia. No significant increase in erythrocyte GSH concentration was noted in either group at any time point. Two dogs in the RibCys group had improved skin and coat health and improved clinical signs of osteoarthritis. No clinical or owner-perceived improvements were noted in the placebo group.
CONCLUSIONS AND CLINICAL RELEVANCE
The RibCys supplement was safe and well tolerated in all dogs. Owners reported improvements in dermatologic and orthopedic conditions in some dogs in the RibCys group. No significant differences were observed in erythrocyte GSH concentration before or after RibCys treatment. This lack of significant differences may have been attributable to the use of healthy dogs, which would not be expected to have depleted GSH concentrations. Given the observed safety profile of RibCys, additional research is warranted to explore the potential usefulness of RibCys supplementation in dogs with cancer and those undergoing treatment for cancer.
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.
Objective—To determine outcome for dogs with
grade-II mast cell tumors treated with surgery alone.
Procedures—Medical records were examined, and
signalment; location and size of tumor; staging status;
dates of local recurrence, metastasis, death, or last
follow-up examination; status of surgical margins; previous
surgery; postoperative complications; and
cause of death were recorded. Follow-up information
was obtained via reexamination or telephone conversations
with owners or referring veterinarians.
Univariate analysis was performed to identify prognostic
Results—60 tumors in 55 dogs were included.
Median follow-up time was 540 days. Three (5%)
mast cell tumors recurred locally; median time to local
recurrence was 62 days. Six (11%) dogs developed
another mast cell tumor at a different cutaneous location;
median time to a different location was 240 days.
Three (5%) dogs developed metastases; median time
to metastasis was 158 days. Fourteen dogs died; 3
deaths were related to mast cell tumor, and 7 were
unrelated. The relationship with mast cell tumor was
not known for 4. Median survival times were 151,
841, and 827 days, respectively, for these 3 groups.
Forty-six (84%) dogs were free of mast cell tumors
during the study period. A reliable prognostic factor
could not be identified.
Conclusions and Clinical Relevance—Results suggest
that additional local treatment may not be required
after complete excision of grade-II mast cell tumors
and that most dogs do not require systemic treatment.
(J Am Vet Med Assoc 2001;218:1120–1123)
Objective—To determine whether argyrophilic nucleolar organizing regions (AgNORs), Ki-67, and proliferating cell nuclear antigen (PCNA) scores were associated with histologic grade and survival in dogs with soft tissue sarcomas (STSs).
Animals—60 dogs with STSs.
Procedure—Medical records were examined and histologic specimens were reviewed. Tissue specimens obtained from archival materials were used to prepare sections for histologic staining for AgNOR and immunohistochemical staining for Ki-67 and PCNA labeling. Follow-up monitoring was obtained by reevaluation or telephone conversations with referring veterinarians or owners.
Results—27 (45%) STSs were grade 1, 23 (38%) were grade 2, and 10 (17%) were grade 3. The mean and median AgNOR, Ki-67, and PCNA scores were determined, and significant positive associations among AgNOR and Ki-67 scores with histologic grade and mitotic score were detected. Fifty-four dogs had adequate follow-up examinations and were included in survival analysis and evaluation of prognostic factors. Overall median survival time was > 1,306 days. Twelve of 54 (22%) dogs died of tumor-related causes. Metastatic disease developed in 8 of 54 (15%) dogs. Results of univariate analysis indicated that increased mitotic score, increased AgNOR score, increased Ki-67 score, incomplete surgical margins, noncurative intent surgery, Ki-67 score greater than the median Ki-67 score, and AgNOR score greater than the median AgNOR score were prognostic factors for decreased survival time. Results of multivariate analysis indicated that increased AgNOR score was the only prognostic factor for decreased survival time.
Conclusions and Clinical Relevance—Results suggested that AgNORs and possibly Ki-67 should be routinely evaluated with histologic grading for STSs in dogs.