Efficacy of omeprazole paste for prevention of gastric ulcers in horses in race training

OBJECTIVE: To determine the minimal effective dosage of omeprazole oral paste for the prevention of naturally occurring ulcers in horses starting race training. DESIGN: Prospective study. ANIMALS: 175 horses. PROCEDURE: Horses in the dose selection portion of the study were sham dose treated or received 1 mg (0.45 mg/lb) or 2 mg (0.9 mg/lb) of omeprazole/kg, PO, every 24 hours for 28 days or 4 mg of omeprazole/kg (1.8 mg/lb; loading dose), PO, every 24 hours for 4 days, then 1 or 2 mg of omeprazole/kg, PO, every 24 hours for 24 days. Horses in the dose confirmation portion of the study were sham dose treated or received 1 mg of omeprazole/kg, PO, every 24 hours for 28 days. Gastric ulcer scores at the beginning and end of the study were compared. RESULTS: Sham-dose-treated horses had significantly higher ulcer scores than did horses treated with any of the omeprazole dosages evaluated. Among horses treated with omeprazole, there was no significant interaction of dose (1 or 2 mg/kg) and loading dose; therefore, the lowest effective dose (1 mg/kg) was evaluated in the dose confirmation portion of the study. In the dose confirmation study, 4 of 39 (10%) sham-dose-treated horses remained ulcer free, which was significantly different from the proportion of horses (31/38 [82%]) receiving 1 mg of omeprazole/kg that remained ulcer free. CONCLUSIONS AND CLINICAL RELEVANCE; Results indicated that omeprazole administered at a dosage of 1 mg/kg, PO, every 24 hours for 28 days was effective for prevention of gastric ulcers in horses starting race training.     

Efficacy of omeprazole paste for prevention of recurrence of gastric ulcers in horses in race training

OBJECTIVE: To determine whether omeprazole oral paste administered at a dosage of 0.5 or 1 mg/kg (0.23 or 0.45 mg/lb), PO, every 24 hours would effectively prevent the recurrence of gastric ulcers in horses in race training. DESIGN: Prospective study. ANIMALS: 135 horses. PROCEDURES: Horses with gastric ulcers were treated with omeprazole at a dosage of 4 mg/kg (1.8 mg/lb), PO, every 24 hours for 28 days. Horses in the dose selection portion of the study were sham dose treated or received 0.5 or 1 mg of omeprazole/kg, PO, every 24 hours for an additional 28 days. Horses in the dose confirmation portion of the study were sham dose treated or received 1 mg of omeprazole/kg, PO, every 24 hours for an additional 28 days. Gastric ulcers were scored before and after the preventive phase of the study (day 28 to day 56) via gastroscopy, and ulcer scores were compared. RESULTS: Sham-dose-treated horses and horses receiving 0.5 mg of omeprazole/kg had significantly higher ulcer scores than did horses receiving 1 mg of omeprazole/kg. There was a significant difference between the proportion of horses receiving 1 mg of omeprazole/kg (38/48 179%]) that remained ulcer free and the proportion of sham-dose-treated horses (7/44 [16%]) that remained ulcer free. CONCLUSIONS AND CLINICAL RELEVANCE: Omeprazole oral paste administered at a dosage of 1 mg/kg, PO, every 24 hours for 28 days was effective for prevention of recurrence of gastric ulcers in horses in race training.     

Inheritance of recurrent exertional rhabdomyolysis in thoroughbreds

OBJECTIVE: To develop a diagnostic test for recurrent exertional rhabdomyolysis (RER) in Thoroughbreds that relied on in vitro contracture of muscle biopsy specimens and determine whether the inheritance pattern of RER diagnosed on the basis of this contracture test was consistent with an autosomal dominant trait. DESIGN: Clinical trial. ANIMALS: 8 adult horses with RER and 16 control adult horses for development of the contracture test; 23 foals for inheritance of RER. PROCEDURE: External intercostal muscle biopsy specimens from the 24 adult horses were tested for contracture in response to halothane and caffeine, and criteria for a positive test result were determined. These criteria were then applied to results for the 23 foals to determine whether they had RER. Simple segregation analysis was performed to determine whether results were consistent with a dominant pattern of inheritance. RESULTS: Results of the contracture test were positive for 5 of the 12 colts and 4 of the 11 fillies. Results of segregation analysis were consistent with an auto-. somal dominant pattern of inheritance. Two sires with RER produced colts with RER, supporting the hypothesis that RER had an autosomal, rather than an X-linked, inheritance pattern. In addition, in 1 instance, an unaffected colt was produced by 2 affected parents, which was not consistent with a recessive mode of inheritance. CONCLUSIONS AND CLINICAL RELEVANCE: Although the expression of the RER trait is influenced by sex, temperament, and diet, among other factors, results from the in vitro muscle contracture test and this breeding trial suggest that RER in Thoroughbreds can be modeled as a genetic trait with an autosomal dominant pattern of inheritance.     

A case of coccygeal chondroid chordoma in a cat: morphological and immunohistochemical features

In August 2007, a 4-year-old, intact, female Domestic Shorthair cat was examined for a mass on the tip of the tail. Histological examination performed after apical caudectomy revealed a neoplasm affecting the distal part of the last coccygeal vertebra. The neoplasm consisted of lobules of physaliferous cells surrounding cartilaginous tissue and a central core of trabecular bone. A diagnosis of chondroid chordoma was made based on histomorphological features and immunohistochemical results. Chondroid chordoma has been previously reported in humans, rats, ferrets, and mink. To the authors' knowledge, chondroid chordoma has not been reported in cats. Neither recurrence nor metastasis was reported 7 months after surgery.