摘要:

The macroscopic, light microscopic, and electron microscopic features and biological properties of MC‐29 virus‐induced hepatocellular carcinomas in chickens are described. The tumors developed in noncirrhotic livers within a very short time and formed metastases. Virus production was also evidenced in the tumors. There were also indications of virus production in the transplantable tumors. The tumors grew equally well after sc, ip, or im inoculation. In about 25% of the tumor‐bearing animals, tumorous nodules developed in the liver. It could not be established whether they were metastases or primary liver cancers induced by viruses released from the transplantable tumors.

ISSN:0098-4108    

DOI:10.1080/15287397909529760

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Studies were performed to test the applicability of the molecular correlation concept developed in chemically induced transplantable rat hepatomas to virally induced transplantable hepatoma in chicken. In a comparison of the activities of carbohydrate, purine, and pyrimidine key enzymes in rat and chicken hepatomas, similar patterns were observed in rodent and avian tumors. These results show that the enzymatic imbalance elucidated in chemically induced rat hepatomas is applicable to the virus‐induced hepatoma in chicken, independent of the nature of the carcinogenic agent and the species.

ISSN:0098-4108    

DOI:10.1080/15287397909529761

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The disorder of gene expression in hepatomas was studied by following certain metabolic alterations (enzyme stimulation, nucleic acid labeling) after glucocorticoid treatment and analyzing the site of action of glucocorticoids. Compared to normal liver, the MC‐29 virus‐derived transplantable hepatoma (VTH) responded abnormally to glucocorticoids, which failed to stimulate the activity of certain enzymes (glucose‐6‐phosphatase, aryl hydrocarbon hydroxylase) or to inhibit DNA synthesis. Since the binding capacity of the cytosol steroid receptor was the same in liver and VTH but the interaction between the steroid receptor and DNA was reduced in VTH, it was concluded that structural alterations of chromatin nonhistones—including processed steroid receptor—may be responsible for the lack of physiological responses to steroids in VTH. Furthermore, the increased proportion of repetitive sequences in VTH DNA may be a feature of the disorder of gene regulation in malignant cells.

ISSN:0098-4108    

DOI:10.1080/15287397909529762

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The transplantable MC‐29 virus‐derived hepatoma is a suitable model for studying the influence of immune status on virus‐derived hepatomas in chickens. It was found that both humoral and cellular immunologic reactions have a role in the pathogenesis of virus‐derived hepatomas and that virus‐derived hepatomas con be influenced by nonspecific Immunostimulation. The lymphoid system was profoundly altered in hepatoma‐bearing chickens; this cannot be neglected when studying correlations between immune reactions and carcinogenesis. Profound changes were also observed in protein synthesis and the steroid receptor system of hepatoma‐bearing chickens compared to healthy birds; this also complicates the understanding of the role of immune mechanisms in carcinogenesis.

ISSN:0098-4108    

DOI:10.1080/15287397909529763

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Immunization of CBAT6T6 mice with MC‐29 hepatoma antigen did not change the take of Rous sarcoma virus, Schmidt‐Ruppin strain [RSV(SR)] mouse tumors after sc transplantation. Immunization with MC‐29 hepatoma antigen only slightly increased the average survival time of the mice and significantly decreased tumor growth only at the minimal lethal dose level. Immunization of mice with MC‐29 hepatoma antigen and immunization with chicken Rous sarcoma gave similar results; both elicited much less transplantation resistance than immunization with irradiated RSV(SR) mouse tumor cells. The data indicate that there are common tumor‐specific transplantation antigens of MC‐29 hepatoma and Rous sarcoma, but further in vitro experiments are needed to prove this.

ISSN:0098-4108    

DOI:10.1080/15287397909529764

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Hepatic tumors were induced in medakas (Oryzias latipes) by the addition of diethylnitrosamine (DEN) to their aquarium water. Medakas are useful for study because they are highly susceptible to the carcinogenic effect of DEN and the time for tumor induction is relatively short. Tumors had a histological pattern similar to that of mammalian hepatic tumors. The medaka seems to be susceptible to water‐soluble carcinogens.

ISSN:0098-4108    

DOI:10.1080/15287397909529765

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Isolation of preneoplastic cell populations would greatly facilitate analysis of the development of liver carcinogenesis. Suspensions of intact single cells can be prepared in an almost quantitative yield by two‐step perfusion of the isolated liver. In the first step the liver is perfused with a Ca2+‐free buffer (or with EGTA) in order to irreversibly cleave the desmosomes; in the second step perfusion with Ca2+‐activated collagenase dissolves the collagenous extracellular matrix.

ISSN:0098-4108    

DOI:10.1080/15287397909529766

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A variety of liver and hepatoma cell lines were incubated in the presence of corticosterone. DNA synthesis was inhibited in some but not all cell lines. One of them, the Fu 5a clone of the Reuber hepatoma cell line, was subjected to corticosterone for 48 h. Incorporation of labeled thymidine into DNA was inhibited up to 10%. Afterward, corticosterone was removed. DNA synthesis then increased 16‐fold relative to controls. It was concluded that corticosterone blocks these cells in late G1phase of the cell cycle and thus leads to synchronization.

ISSN:0098-4108    

DOI:10.1080/15287397909529767

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Approximately one‐third of the cells in the liver are nonhepatocytes. Of these, the Kupffer cells, or phagocytes lining the sinusoids, are of particular significance since environmental carcinogens must first traverse a Kupffer cell barrier before reaching the liver parenchyma. Phagocytosis and subsequent degradation of carcinogens by Kupffer cells lead to their permanent removal. Factors such as membrane receptors, which determine the avidity of Kupffer cells for various substances, would consequently have a decisive role in the primary interaction between carcinogens and Kupffer cells. Likewise, the intracellular lysosomal apparatus, which determines the ability of these cells to degrade various substances, would determine whether these substances can persist in an active form. In vivo data on Kupffer cell clearance of various substances are plentiful. However, to dissect the complex problem of Kupffer cell interaction with carcinogens, a clear‐cut in vitro system would certainly be useful. A system for separating Kupffer cells from other types of liver cells and maintaining pure Kupffer cell cultures has been achieved in recent years. Some basic cell biological studies—such as studies of membrane receptors and lysosomal enzyme apparatus‐have already been carried out. It could now be rewarding to adopt the system for in vitro studies of Kupffer cell interactions with carcinogens.

ISSN:0098-4108    

DOI:10.1080/15287397909529768

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

ISSN:0098-4108    

DOI:10.1080/15287397909529739

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor