Liver cultured cells from

The test can be carried out on cultured cells or on cells from animals treated in vivo. In the former case the test chemical is usually evaluated in the presence and absence of the S-9 activation system from rat liver. Typically cells from a Chinese hamster ovary cell line are incubated in a liquid medium and exposed to several concentration of the test chemical, either with or without the S-9 fraction, for about 2 hours. Positive controls, such as ethyl methane sulfonate (a direct-acting compound) or dimethylni-trosamine (one that requires activation), as well as negative controls are also included. Test concentrations are based on cell toxicity levels determined by prior experiment and are selected in such a way that even at the highest dose excess growth does not occur. At the end of the treatment period the cells are washed, bromodeoxyuridine is added, and the cells are incubated for 24 hours or more. The cells are then fixed, stained with a fluorescent dye, and irradiated with UV light. Second division cells are scored under the microscope for SCEs (Figure 21.7). 

Fig. 6. Comparative analyses of endogenous (ADPR)n nonhistone proteins from different hepatic tissues. The endogenous poly(ADPR) nonhistones were isolated from different types of untreated liver cells. Electrophoretic analyses were performed on 7% polyacrylamide gels using the Tris/ phosphate buffer system [11 at pH 6.0 in the presence of 0.1% sodium dodecyl sulfate and 6 M urea. Gels were stained with silver stain (Bio-Rad, Miinchen). Samples applied to the gel correspond to the yield obtained from 10 cells./ip Yoshida hepatoma AH 1914 nh normal hepatocytes after 44 h in primary culture It normal liver tissue cells from whole animals ma marker proteins from top to bottom Myosin (200 kD), ]3-galactosidase (116 kD), phosphorylase b (92 kD), bovine serum albumin (66 kD)...

It has been noted that cell cultures derived from trout (66, 67) and trout liver microsomes (U2, U7, 68) may have relatively high AHH activity (BP hydroxylase) which sometimes exceeds the activity observed in control rat liver microsomes. The metabolite pattern obtained using trout liver microsomes resembled that produced by MC treated rat liver microsomes (P-Uh8)(6 and Ahokas, Saarni, Nebert and Pelkonen, manuscript in preparation Table IV). Associated with this pattern of BP metabolites was covalent binding to DNA which was three times as high as obtained by using rat liver microsomes. Another species of fish (roach), on the other hand was found to be almost inactive in catalyzing in vitro bind-... 

Genotoxic effects have been reported in animals treated with 3,3 -dichlorobenzidine. A single dose of 3,3 -dichlorobenzidine (1,000 mg/kg) administered to male and pregnant female mice induced micronuclei in polychromatic erythrocytes in the bone marrow of the males and in the liver of the fetuses, but not in bone marrow of the dams (Cihak and Vontorkova 1987). A micronucleus test is performed to detect a chemical s ability to induce chromosomal aberrations. However, the relevance of micronuclei formation to human health is not known. The reason for the lack of effect of 3,3 -dichlorobenzidine on bone marrow micronuclei formation in the mothers is unclear, but it may be related to deficiencies in the metabolic activation of 3,3 -dichlorobenzidine in female mice. The relative importance of pregnancy is unknown since the study did not evaluate nonpregnant females. In another study, an increase in unscheduled deoxyribonucleic acid synthesis (UDS) was observed in cultured liver cells from male mice previously pretreated orally with single doses of 500 mg/kg 3,3 -dichlorobenzidine no response was observed at a dose of 200 mg/kg (Ashby and Mohammed 1988). 

The level of enzyme needed can influence the choice of preparation used for the study. Microsomal preparations from cell cultures allow the use of higher concentrations of active enzyme per unit volume than use of whole cells or cell lysates. The use of whole, viable cells allows the use of longer incubation times but at a lower enzyme concentration per unit volume. In addition, adequate oxygen transfer and nutrient concentrations are needed to maintain culture viability. These requirements impose limitations on cell concentration. In addition, microsomes cannot be efficiently prepared from all cultured cell types. We have found that standard microsome preparation procedures as used for human or rodent liver were unsuitable for isolating active enzymes from human lymphoblasts, and this appears to be a general property of cultured cell lines. Specific catalytic activities in microsomes were lower than for whole cell lysates. This loss of activity appears to happen in other mammalian cell systems which has led to the common use of whole cell lysates.With human lymphoblasts, shortening the length of... 

Joplin, R., Strain, A J, and Neuberger, J. M. (1989) Immuno-isolation and culture of biliary epithelial cells from normal human liver In Vitro Cell Dev Biol 25, 1189-1192. 

Serum proteins from cell culture medium PDMS Human liver carcinoma cells Photocatalitc hydrophilization of PDMS (mask lithography) 2009 [163]... 

Table 2.1 shows some adherent and suspension cell lines that are commonly cultured. Cell shape usually reflects their origin. Blood cells (such as those derived from lymphomas) generally grow in suspension, while cells derived from solid tissues (such as kidney and liver) are adherent cells. Typical morphologies of different cell types are shown in Figure 2.4 (see color section). 

Conjugation of 4-nitrophenol also occurred in cultured skin epithelial cells from humans (Rugstad and Dybing 1975), in isolated rat hepatocytes (Araya et al. 1986 Moldeus et al. 1976 Tonda and Hirata 1983), and in microsomes isolated from dog livers (Nakano et al. 1986). 

Evidence has accumulated for the existence of a specific deiodinase for the inner ring of iodothyronines which is further distinguished from the type I enzyme because of its insensitivity to sub-mM PTU concentrations. Thus, type III iodothyronine deiodinase converts T4 to rT3 but not to T3 and produces 3,3 -T2 from T3 but not from rT, (Table I). It has been detected in chick embryo heart [94] and liver [95] cells, monkey hepatocarcinoma cells [96], rat CNS [71,75,97], human [98], rat [98] and guinea pig [99] placenta, and rat skin [100], With higher enzyme activities in cerebral cortex than in cerebellum, the distribution of the type III deiodinase is different from that of the type II enzyme [75], In brain cell cultures type III deiodination appears associated with the presence of glial cells [76,78,79],... 

Although there has been emphasis on rabbit liver, GH receptors have been studied in liver from many other species and in many other tissues and cultured cell lines [17,18]. The human lymphocyte-derived cell line, IM9, has provided a useful source, though the physiological significance of binding of GH to these cells is not clear. The binding and structural properties of GH receptors vary considerably according to the tissue and species from which they are derived. 

Somatomedins have now been isolated from many other species. The sequences of bovine and mouse somatomedins C have been reported. Rat somatomedin C/IGF-I differs from the human protein at a few residues, and the complete sequence of the gene that codes for it has been determined [47]. Rat IGF-II is probably identical to another polypeptide, multiplication stimulating activity (MSA), which is produced by a rat liver-derived cell line (BRL cells) and stimulates the growth of many cells in culture. 

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