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A 225-day-old male fourth generation rat from a developing recombinant inbred line (Lewis x Brown Norway) had a bilaterally symmetrical enlargement of the scrotum. Palpation indicated the presence of a firm lobulated mass extending from the tip of the scrotum to the abdominal wall. Bilateral nodular masses totally occupied the scrotal sacs, surrounded the testicles, and extended along the spermatic cords into the abdominal cavity. Tumor nodules also were present in the intestinal mesentery, omentum, mesenteric lymph nodes, pancreas, and lung. Histologically, the neoplasm presented a spectrum of characteristics varying from that of a granuloma with giant cells to a diffuse proliferation of spindle-shaped mononuclear cells.

The responses of 2 inbred strains of rats to intramuscular doses of ketamine and xylazine, singly and in combination, were studied. A synergistic effect was observed when the 2 drugs were administered together, which resulted in anesthesia with extended analgesia and immobility. Anesthesia was achieved in most rats given 87 mg ketamine/kg of body weight and 13 mg xylazine/kg, beginning 10 to 15 minutes after simultaneous injection and lasting 15 to 30 minutes, then followed by a relatively long period of immobility (mean, 3.8 hours) and reduced responsiveness to external stimuli. Some rats required up to twice this dose for adequate surgical anesthesia. Total doses (initial and supplemental) of up to 3 times the amount were administered with apparent safety.

A canine bladder epithelial cell strain was established in culture for the study of canine distemper virus. Epithelial cells were scraped off the bladder with a scalpel and were cultured in enriched Eagle's medium. Cells were enzymatically dispersed and passed over 46 population doublings which covered a period of more than 3 years. The cells were heteroploid when karyotyped at passage level 5 and 42. This cell strain permitted direct isolation of canine distemper virus and also showed susceptibility to laboratory strains of measles virus. Seemingly, establishment of cell strains from canine bladder epithelium can be accomplished without difficulty.

Approximately 80% of a colony of 900 Long Evans rats, Blu:(LE), gnawed on polypropylene shoe box type cages around the automatic watering grommet. The gnawing led to cage destruction and escape of the animals. The addition of a large stainless steel shield between the original grommet backing and the cage prevented further gnawing on the cage.