Safety and efficacy of a ribose-cysteine supplement to increase erythrocyte glutathione concentration in healthy dogs.

OBJECTIVE: 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. ANIMALS: 24 healthy adult dogs. PROCEDURES: 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. RESULTS: 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.

Feline large-cell lymphoma following previous treatment for small-cell gastrointestinal lymphoma: incidence, clinical signs, clinicopathologic data, treatment of a secondary malignancy, response and survival.

OBJECTIVES: Lymphoma is a common and clinically important malignancy in cats. Development of a second malignancy has been reported previously in 7-14% of cats with small-cell gastrointestinal (GI) lymphoma. The aim of our study was to describe the incidence, clinical signs, clinicopathologic data, response to therapy and outcomes in cats diagnosed with large-cell lymphoma following treatment for small-cell GI lymphoma. METHODS: Medical records from a single referral specialty hospital were reviewed for all cats with lymphoma diagnosed between 2008 and 2017. The cases with a diagnosis of small-cell GI lymphoma followed by a diagnosis of any large-cell lymphoma and complete outcome data were selected for further review. RESULTS: Seven hundred and forty cats with a diagnosis of lymphoma were identified. Twelve cats (12/121) treated for small-cell GI lymphoma followed by a diagnosis of any anatomic form of large cell lymphoma were identified. Nine cats met the study inclusion criteria and were used in analyses. Mean event-free survival time from small-cell GI lymphoma diagnosis until diagnosis of large-cell lymphoma was 543 days, with a median survival time of 615 days. Mean event-free survival time from large-cell lymphoma to death was 55 days, with a median survival time of 24.5 days. Hematocrit, albumin and total protein were significantly decreased when cats developed large-cell lymphoma compared with their values at the time of small-cell lymphoma diagnosis. CONCLUSIONS AND RELEVANCE: Large-cell lymphoma occurred in 9.9% (12/121) of cats treated for small-cell GI lymphoma. Feline practitioners should include large-cell lymphoma on their list of differential diagnoses in cats diagnosed with small-cell GI lymphoma developing weight loss, anemia, hypoalbuminemia and hypoproteinemia.