Fetal hamster cells

A more dramatic prediction of the post-transcriptional control model is also substantiated in Figure 6. Following deinduction of a culture inhibition of RNA synthesis should rescue the repressed mRNA and reactivate enzyme formation. Experiments in accord with this prediction were done in HTC cells (Tomkins et al., 1969,1970 Levinson et al., unpublished), and in cultured fetal hamster cells (Bausserman and Nebert, 1970). The results are in remarkably good agreement. In the experiment using HTC cells (Fig. 6) the inducer was removed from the induced culture, and after specified intervals AMD was added to the deinduced culture. As illustrated, TAT formation was reactivated shortly after addition of the inhibitor. Similar results are obtained when the nucleoside analog mercaptopyridethylbenzimidazole (MPB) was used instead of actinomycin D (Levinson, unpublished Tomkins et al., 1970). 

Lichtenberg, G, Nowak, C., Gleier, K., Meckert, C.. Richter-Reichhelm, H.-B. (1995) Anchorage independent colony growth of fetal hamster lung epithelial cells after treatment with diepoxybutane. Toxicol. Lett., 75, 193-199... 

Markovits, P., Levy, S., Nocentini, A., Velizarov, A., Sabharwal, P.S., Benda, P. (1976). Invitro malignant transformation of fetal hamster brain cell by benzo(a)pyrene. CRAcad.Sci. 282 2015-20. 

Emura M, Mohr U, Riebe M, et al. 1987. Predispostion of cloned fetal hamster lung epithelial cells to... 

Emura M, Richter-Reichhelm HB, Schneider P. et al. 1980. Sensitivity of Syrian golden hamster fetal lung cells to benzo(a)pyrene and other polycyclic hydrocarbons in vitro. Toxicology 17 149-155. 

Syrian hamster embryo and mouse CSH lOTl/2 cells were used for transformation assays. Hamster cells were prepared and grown in Dulbecco s modified Eagle s medium supplemented with 10% fetal calf serum, penicillin (50 U ml" ), and streptomycin (50 jug ml" GIBCO), as previously described [4]. 

Ito T, Nogawa H, Udaka N, Kitamura H, Kanisawa M. Development of pulmonary neuroendocrine cells of fetal hamster in explant culture. Lab Invest 1997 77 449-457. 

Iron appeared to reduce the effects of orally or subcutaneously administered lead on blood enzyme and liver catalase activity (Bota et al. 1982). Treatment of pregnant hamsters with iron- or calcium-deficient diets in conjunction with orally administered lead resulted in embryonic or fetal mortality and abnormalities (ranting, edema) in the litters, while treatment with complete diets and lead did not (Carpenter 1982). Inadequate levels of iron in association with increased body burdens of lead enhanced biochemical changes associated with lead intoxication (Waxman and Rabinowitz 1966). Ferrous iron was reported to protect against the inhibition of hemoglobin synthesis and cell metabolism by lead it has been speculated that iron competes with lead uptake by the cell (Waxman and Rabinowitz 1966). In... 

Although plant cell culture is not as cost effective as plant cultivation in the open field, it will become an economical process if higher protein yields can be achieved [58]. The cultivation medium of plants is chemically defined, consisting of a carbon source, minerals, vitamins and phytohormones [69]. Furthermore, it is protein-free and relatively inexpensive. In contrast, animal cells often require complex supplements such as fetal calf serum and/or expensive growth factors, although serum-free cultivation is possible in case of Chinese hamster ovary (CHO) cells [70]. 

Microwaves inhibit thymidine incorporation by DNA blockage in cultured cells of the Chinese hamster irradiated cells had a higher frequency of chromosome lesions (Garaj-Vrhovac et al. 1990). Microwaves induce teratogenic effects in mice when the intensity of exposure places a thermal burden on the dams and fetuses, resulting in a reduction in fetal body mass and an increased number of resorptions (O Connor 1990). 

McDowell, E. M., Ben, T., Newkirk, C., Chang, S., and De Luca, M. (1987b). Differentiation of tracheal mucociliary epithelium in primary cell culture recapsulates normal fetal development and regeneration following injury in hamsters. Am. J. Pathol. 129,511-522. 

The induction of the CYPs has been demonstrated in many different species including humans, and in various different tissues as well as the liver. Induction usually results from repeated or chronic exposure, although the extent of exposure is variable. The result of induction is an increase in the amount of an enzyme induction requires de novo protein synthesis, and therefore an increase in the apparent metabolic activity of a tissue in vitro or animal in vivo. Consequently, inhibitors of protein synthesis, such as cycloheximide, inhibit induction. It is a reversible cellular response to exposure to a substance. Thus, it can be shown in isolated cells, such as hamster fetal cells in culture, that exposure to benzo[a]anthracene induces aryl hydrocarbon hydroxylase (AHH) activity (CYP1A1). 

Figure 1, Lightly packed (left) and densely packed (right) normal Syrian hamster fetal cells. Cultures of Syrian hamster fetal cells were obtained from minced whole embryos by trypsin treatment (see Methods for details). These cultures were untreated in parallel with cultures exposed to various carcinogens. The cultures were washed and the cells replated to form colonies in fresh medium. Following two weeks of incubation the cultures were fixed and stained with a crystal violet solution. Note the orderly growth of normal cells in the...

Figure 4, A tightly packed, piled-up normal Syrian hamster fetal cell colony. Treatment with some of the metal carcinogens induced a higher incidence of these tightly packed/piled up normal colonies. This type of colony was also present in untreated cultures.

Cultures of secondary Syrian hamster fetal cells were prepared with 10 cells per 35-mm plates. Following a 24-hr period of attachment the monolayer was treated two times for two days with various concentrations of the metal compounds as shown in the figure. The metal compounds were then removed by washing the mono-layer extensively with saline A and the cultures were incubated for 18-21 days with fresh Dulbecco s medium supplemented with 10% fetal bovine serum. The cultures were refed two times per week. The plates were then fixed and stained as described in Methods. Acetone was used to sterilize the metal compound. The number of transformed foci was determined per plate. Each point shown in the mean SEM for at least six plates. 

Syrian hamster fetal cells were treated with the various metal compounds shown in the table for 8-8 days. The compounds were removed by washing the cells with saline A. The cells were trypsinized and 10,000 ceUs were replated with fresh inedia into 35-mm plates and allowed to proliferate for two weeks. The plates containing... 

Quarles JM. Sega MW, Schenley CK. et al. 1979. Transformation of hamster fetal cells by nitrosated pesticides in a transplacental assay. Cancer Res 39 4525-4533. 

In Vitro Cell Culture. Mouse leukemia L1210 cells (designated K25) were grown in RPMI 1630 medium supplemented with 20% heat-inactivated fetal calf serum. V79 Chinese hamster lung cells were grown in o-MEM medium with 5% fetal calf serum In 7.5% CO2. The human cell lines were grown in Eagle s minimal essential medium with 10% fetal calf serum. 

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