Hamster Armenian

After 24 hr for Chinese hamsters and 48 hr for Armenian hamsters, anesthetize animals with clinical Nembutal (50 mg/ml) using 0.01 ml/10 body weight (Chinese hamsters) and 0.015 ml/10 g body weight (Armenian hamsters). 

Anesthetize males with Nembutal (sodium pentobarbital, 50 mg/ml, clinical). For Chinese hamsters inject Nembutal at a dose of 0.01 nJ/10 g body weight intraperitoneally. For Armenian hamsters this amount should be increased by an additional 0.01 mg for the entire animal. In about 5 min the animals are ready for operation. If the animal is not anesthetized in 5 min, place it in a glass jar containing chloroform on a cotton pad. Remove animal when breathing becomes shallow. 

With scissors make a vertical incision 13-15 mm long for the Chinese hamster and 8-10 mm long for the Armenian hamster so as to pass through the peritoneal membrane. 

Mutagenic effects of monofunctional alkylating chemicals in vivo have already yielded substantial results. Toxicity trials indicate that the Armenian hamster is two and a half times more sensitive than the mouse to ethyl methanesulfonate (Lavappa and Yerganian, 1969). With regard to induction of chromosomal anomalies, intraperitoneal administration of low doses (100 mg/kg) of ethyl methanesulfonate is sufficient to produce an overall incidence of 30% viable translocations in the male progeny. Furthermore, translocated chromosomes and bivalents can be accurately identified in terms of specific sites of breakage and reunion in both spermatogonia and spermatocytes (Table 2). Since the translocated F males are found in litters... 

Ethyl carbamate (urethan), another monofunctional alkylating agent, when administered intraperitoneally (100 mg/kg) will not have any noticeable effect on meiotic chromosomes. If the same dose is given to F2 male Armenian hamsters derived from grandsires treated with ethyl methane-sulfonate, totally different results are obtained—1 to 7 days after treatment there are no chromosome anomalies on day 8 the number of bivalents is reduced from 11 to ten and nine. In 80% of the spermatocytes ten bivalents can be encountered, and in about 10% of the spermatocytes nine bivalents are encountered. The reduction in the number of bivalents was due to associations of two and/or three bivalents. 

Origins of parental lines 3460, 3460-3, Cl 1 D, 2472-6, 2472-6-3 see Table 1. WI-38 embryonic diploid human lung fibroblasts (Hayflick and Moorhead, 1961). SV-SD-C clonal derivative of SV40 transformed human skin fibroblasts (Todaro, Wolman, and Green). 6 B Armenian hamster fibroblasts transformed by adenovirus type 18 (Yerganian and Nell, 1966). 12 E Chinese hamster fibroblasts transformed by adenovirus type 7 (Yerganian and Nell, 1966). 

By the use of UV-inactivated Sendai virus, Yerganian and Nell (1966) have obtained hybrids between somatic cells of the Armenian and Chinese hamsters (transformed by human adenoviruses, types 18 and 7, respectively). Two days after the exposure of die mixed cell suspension to the virus, 18 hybrid metaphases were recorded. These metaphases contained the expected chromosome complements of die two species but these were markedly out of phase with respect to spiralization or contraction of the chromosomes. This asynchrony was apparently transitory, for a second karyological analysis, performed 7 days after exposure of the cells to the virus, showed no such asynchrony in the hybrid metaphases. 

---