Electrophoretic resolution of two rat class I alloantigens expressed on (WF X F344)F1 liver cells in primary culture.

Polyvalent alloantisera, prepared by reciprocal immunization of F344 (RT1lv1 haplotypes) and WF (RT1u haplotype) rats, as well as monoclonal antibodies, were used to immunoprecipitate class I alloantigens from detergent extracts of monolayer cultures of 35S-methionine-labelled liver cells. Two-dimensional IEF/SDS-PAGE gel analysis resolved the RT1.Alv1 and RT1.

Effects of selenium on cell proliferation in rat liver and mammalian cells as indicated by cytokinetic and biochemical analysis.

Studies were conducted in vivo with regenerating liver and in vitro with mammalian cells to determine the effects of selenium on cell proliferation and the stages of the cell cycle affected by selenium. Six ppm selenium as Na2SeO3 fed to weanling male F344 rats for 6 wk significantly reduced the percentage of 3H-labeled hepatocyte nuclei by one-half compared to 0.1 ppm selenium when [methyl-3H]thymidine was injected at 23 h post-two-thirds hepatectomy.

Effects of dietary selenium concentration on the development of enzyme-altered liver foci and hepatocellular carcinoma induced by diethylnitrosamine or N-acetylaminofluorene in rats.

Three protocols were used to determine the effects of dietary selenium concentration on the development of gamma-glutamyl-transpeptidase (GGT)-positive foci and hepatocellular carcinoma induced by either diethylnitrosamine (DEN) or N-acetylaminofluorene in rats. In the first experiment, foci were induced by a carcinogenic dose of DEN (100 mg/kg body weight, p.o.

Ultrastructural and cytochemical study of the early stages of liver colonization by transplanted neoplastic hepatocytes.

Neoplastic liver cell colonies were induced in the livers of isogeneic F344 rats by intraportal injection of a hepatic cell suspension from diethylnitrosamine-treated donor rats. Examination of the livers 12 days after cell implantation revealed well-demarcated groups of liver cells. The colonies showed alterations of the normal hepatocyte phenotype, which were clearly demonstrated by histologic, cytochemical, and electron microscope techniques.

Immunological approaches to the purification of putative premalignant hepatocytes from genotypic mosaic rat livers.

Surface-localized rat RT1 alloantigens on isolated hepatocytes have been used to achieve partial purification of putative premalignant liver cells from rats undergoing chemically induced hepatocarcinogenesis. Genotypic mosaic rat livers were constructed by transplantation of carcinogen-altered F-344 (RT1Iv1) or WF (RT1u) donor liver cells into livers of WF X F-344 F1 host rats, whose liver cells bear alloantigens of both parental strains: WF and F-344, RT1u and RT1Iv1, respectively (J. M.

DNA adduct formation, removal and persistence in rat liver during one month of feeding 2-acetylaminofluorene.

Male Wistar-Furth rats were fed 0.02% 2-acetylaminofluorene (AAF) for 3 days or 0.02% AAF for 25 days followed by 0.

Toxicity of aflatoxin B1 in rat and mouse hepatocytes in vivo and in vitro.

The reported LD50 for the adult, male Fisher rat is 1.2 mg aflatoxin B1/kg body weight (i.p.

Determination of 2-acetylaminofluorene adducts by immunoassay.

Antisera elicited in rabbits were used in radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) to determine femtomole quantities of deoxyguanosin-(8-yl)-acetylaminofluorene (dg-8-AAF) and deoxyguanosin-(8-yl)-aminofluorene (dg-8-AF). These adducts have been monitored in liver and kidney DNA of male Wistar-Furth rats fed 0.02% or 0.

Formation and removal of (guan-8-yl)-DNA-2-acetylaminofluorene adducts in liver and kidney of male rats given dietary 2-acetylaminofluorene.

Radioimmunoassay has been used to measure acetylated and deacetylated deoxyguanosine C-8 DNA adducts of 2-acetylaminofluorene in liver and kidney DNA of male Wistar-Furth rats fed a dietary regimen of 0.02 or 0.04% 2-acetylaminofluorene.

Application of quantitative stereology to the evaluation of enzyme-altered foci in rat liver.

The mathematical science of quantitative stereology has established relationships for the quantitation of elements in three-dimensional space from observations on two-dimensional planes. This report describes the utilization and importance of such mathematical relationships for the quantitative analysis of focal hepatic lesions in terms relative to the volume of the liver. Three examples are utilized to demonstrate the utility of such calculations in the three-dimensional quantitation of hepatic focal lesions.

Alloantigen-mediated adherence of rat hepatocytes to antibody-coated polystyrene dishes.

Rat alloantigens expressed on normal hepatocytes have been utilized in a cell "panning" procedure to mediate the haplotype-specific adherence of collagenase-isolated hepatocytes to antibody-coated polystyrene dishes. A polyvalent F344 anti-WF alloantiserum was prepared by immunizing F344 rats with WF tissue. The alloantibody IgG purified from the alloantiserum, when reacted with either WF or (WF X F344)F1 hybrid rat hepatocytes, caused the adherence of these hepatocytes to bacteriological-grade polystyrene dishes coated non-specifically with a xeno-antibody, rabbit anti-rat IgG.

Resistance to the cytocidal effects of adriamycin is an early phenotypic change induced during hepatocarcinogenesis.

Resistance to the cytocidal action of Adriamycin (ADR) was induced in rat hepatocytes by incorporation of the carcinogen 2-acetylaminofluorene (AAF) into the rat diet. Using a quantitative assay in primary monolayer culture, it was demonstrated that resistance to ADR is an early phenotypic change that is induced during chemical carcinogenesis in the rat, and appears to be stable.

Carcinogen-induced drug resistance in rat hepatocytes.

The relative resistance of liver cells in primary monolayer cell culture to the cytocidal effects of methotrexate, Adriamycin, cycloheximide, or aflatoxin B1 was studied using cells derived from normal rats, rats subjected to two-thirds hepatectomy, or rat fed dietary carcinogen. Normal rat liver cells were highly sensitive to the toxic effects of methotrexate. Adriamycin, cycloheximide, and aflatoxin B1.

Search for endogenous liver colony-forming units in F344 rats given a two-thirds hepatectomy during short-term feeding of 2-acetylaminofluorene.

To search for endogenous liver colony-forming units in livers of male F344 rats, three cell selection regimens were used. Rats were given a two-thirds hepatectomy (PH) on Day 7 of a 14-day dietary administration of the hepatocarcinogen 2-acetylaminofluorene (AAF), given at a concentration of 0.02, 0.

Transfer of viable putative preneoplastic hepatocytes to the livers of syngeneic host rats.

A new approach was developed by which freshly isolated, chemical carcinogen-altered hepatocytes with the positive marker gamma-glutamyl transpeptidase (gamma-GT) could be transferred from adult donor F344 rats to the livers of syngeneic, adult host rats. Selective proliferation of gamma-GT-positive hepatocytes was induced in host rat livers, such that large, macroscopic colonies of altered hepatocytes could be generated within 10 days of the cell transfer operation. Quantitation of the number of gamma-GT-positive hepatocyte colonies (foci) appearing per square centimeter of host liver section area on day 10 following cell transfer revealed that prior treatment of host rats with a low dose of 2-acetylaminofluorene was essential for the appearance of large numbers of foci.

Newer insights into the pathogenesis of liver cancer.

A new hypothesis leading to a new model of liver carcinogenesis is described; it is based on the acquisition by carcinogen-altered hepatocytes during initiation of a new functional handle--resistance to the cytotoxicity of a carcinogen--and on the ability of such cells to proliferate in an environment that prevents proliferation of normal hepatocytes. The creation of such a differential environment now enables a quantitative analysis for initiation, the beginning synchronization of the putative premalignant hepatocytes for about 15 cell cycles, the study of the pattern of growth of such resistant cells to form nodules that have some resemblance to the organizational pattern of fetal liver, the analysis of the appearance of distinctive positive and negative markers for these cells, and the further investigation of the development of liver cancer from such cells. The remarkable similarity in overall pattern betweeen the development of cancer in the skin and in the liver with chemicals and the possible role of both somatic mutation and neodifferentiation in carcinogenesis are briefly discussed.

Conditions affecting primary cell cultures of functional adult rat hepatocytes. II. Dexamethasone enhanced longevity and maintenance of morphology.

Primary monolayer cell cultures of adult rat hepatocytes underwent change in morphology and substantial cell loss between 1 and 3 days postinoculation. Dexamethasone-supplementation (1 micronM) of the culture medium maintained the polygonal epithelial morphology of the hepatocytes and increased longevity such that over 80% of the cells survived for 3 days and at least 30% for 8 or 9 days. This enhancement of survival was obtained up to 48 hr postinoculation, but the earlier the time of dexamethason supplementation the greater the effect.

Conditions affecting primary cell cultures of functional adult rat hepatocytes. 1. The effect of insulin.

The conditions for obtaining representative, primary adult rat hepatocyte cultures were explored. The methods applied included enzymatic liver perfusion which was nondestructive to hepatocytes, the prevention of aggregation of dissociated cells and the selective attachment of viable cells. These procedures yielded a recovery of 50% of the liver cells which gave rise to cultures representing 14% of the total liver cells.