[A six-month intravenous repeated dose toxicity study of tazobactam/piperacillin and tazobactam in dogs].

Tazobactam (TAZ) is a newly developed beta-lactamase inhibitor. Tazobactam/Piperacillin (TAZ/PIPC) is a formulation consisting of TAZ and PIPC in a ratio of 1:4. A six-month intravenous repeated dose toxicity study of TAZ/PIPC and TAZ including a one-month recovery period were carried out using male and female dogs. The doses were 200, 400 and 800 mg/kg/day for TAZ/PIPC, and 40, 80 and 160 mg/kg/day for TAZ. The results were as follows. 1. No test article-related deaths occurred during the study period. No effects on clinical findings, body weight and food consumption were evident. 2. No test article-related changes were noted in hematological, serum biochemical and urinalysis evaluations, and opthalmological and electrocardiographic examinations. 3. There were no test article-related changes in macroscopic findings or organ weight. 4. The histopathological examination revealed deposition of marked PAS-positive aggregates in liver cells of dogs given 400 mg/kg/day or more of TAZ/PIPC and 80 mg/kg/day or more of TAZ. Electron micrographs of hepatocytes revealed glycogen granules to be accumulated in the cytoplasm, and an increase of smooth endoplasmic reticulum. 5. After a one-month recovery period, the histopathological changes had generally disappeared, suggesting that they were reversible. 6. From the histopathological changes of liver, the no-toxic dose levels for TAZ/PIPC and TAZ were 200 mg/kg/day and 40 mg/kg/day, respectively.

Periorbital epidermoid cyst in the medial canthus of three dogs.

Periorbital epidermoid cyst in the medial canthus was identified ultrasonographically and confirmed histologically in 3 dogs. Surgical resection of the cysts, with reconstruction of the lacrimal canaliculi, was curative in all 3 cases.

Cryosurgery for treatment of recurrent proliferative keratoconjunctivitis in five dogs.

Cryosurgery was used for treatment of recurrent proliferative keratoconjunctivitis in 5 dogs that had been treated with combined medical and surgical procedures without success. Four dogs recovered completely after one application of cryosurgery. The fifth dog did not respond to cryosurgery until after oral administration of corticosteroids was stopped, indicating a possible immune-mediated mechanism of action of cryosurgery on proliferative keratoconjunctivitis.

Anterior uveal melanoma, with secondary keratitis, cataract, and glaucoma, in a horse.

Intraocular melanoma was diagnosed in a 13-year-old horse. Secondary clinical findings included keratitis, cataract, and glaucoma. The eye was enucleated. Follow-up information did not give an indication of metastatic disease.

Surgical repair of atrial septal defect in a dog.

Atrial septal defect, a relatively rare canine congenital cardiovascular defect, caused syncope during excitement in a 5-year-old male Boxer dog. The defect was successfully repaired by open heart surgery.

Congenital pericardial diaphragmitic hernia and multiple cardiac defects in a litter of collies.

Four Collie littermates had multiple cardiac and diaphragmatic anomalies. Ventricular septal defect was found in 3, pulmonic stenosis in 2, atrial septal defect in 1, mitral regurgitaion in 1, and pericardial diaphragmatic hernia in 3. Five additional littermates died within 72 hours of birth but were not necropsied. On the basis of available evidence, it was believed that the defects were congenital but not hereditary.