ISSN:0021-9541    

DOI:10.1002/jcp.1041290403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0021-9541    

DOI:10.1002/jcp.1041290404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractTransfection assay of NIH 3T3 cells was performed with DNAs isolated from ten human PHC (primary hepatic cancer) specimens and a hepatoma 7402 cell line. Positive results were obtained in 7402 and in six out of ten PHC DNAs. Human N‐rasgene was identified in transfectants from 7402 DNA and transformed cells from three PHC DNA samples, which had passed more than two cycles of transfection. The expression of N‐raswas also remarkably enhanced in six out of nine poly(A)+RNA samples isolated from PHC tissues. P21 synthesis was elevated in 7402 cells as well as in transfectants derived from 7402 cells and PHC DNA. In analysis of PHC DNA, rearrangement and amplification of N‐rasgene was observed in two PHC samples. The discrepancy of results of the transfection assay and mRNA expression was discussed. Furthermore, c‐mycwas also highly expressed in most PHC tissues. It implied that the cooperating activity of N‐rasand c‐mycmight be responsible for the malignant phenotypic alteration in some or most cases in human primary l

ISSN:0021-9541    

DOI:10.1002/jcp.1041290405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractNIH 3T3 cells were transfected with the DNAs from biopsy specimens of human nasopharyngeal carcinoma (NPC, EBV DNA positive) using calcium phosphate precipitation method. The malignant, transformed foci of NIH 3T3 cells have been observed and cloned. The hybridization of transfectant DNA digested by EcoRI with total human leukocyte DNA as probe was performed. The strong signal of smear comparing with NIH 3T3 DNA as control was observed. It was implied that the putative human transforming sequences had been integrated into transformed cells. Employing soft agar culture, the transformed cells can grow and form cell colonies. Following transfer, the foci were able to grow and adhere to a glass wall. These cells were easily agglutinated by con A. The cloned foci have been inoculated into nude mice with the formation of highly malignant sarcomas. In preliminary experiments for characterizing the transforming sequences, Ha‐rasand Blym 1 were found in transfectants derived from one of the NPC DNA samples. It is implicated that these two oncogenes might be responsible for the acquisition of malignant phenotypic character of some human NPC. The further identification of oncogenes in NPC is currently in progres

ISSN:0021-9541    

DOI:10.1002/jcp.1041290406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractRecent studies have indicated the existence of a novel regulatory system governing cell growth and differentiation. The system is based on the cellular homologues of the transforming genes (oncogenes) of retroviruses. Cellular oncogene products include regulators of the cell generation cycle, cell‐surface receptors, and growth factors. Preliminary evidence is available that this regulatory system is important in hemopoiesis. In this paper, the biology of the blast cells of acute myeloblastic leukemia is reviewed. Data is presented indicating that genetic control may be exercised in the nucleus to affect self‐renewal, at the cell surface, to mediate cell‐to‐cell interactions and through the environment by the production of growth factors. These findings support the suggestion that the blast population is a suitable model for studying oncogene‐based regulation. Blasts have the further advantage that laboratory observations made with their use can be correlated with the clinical course of th

ISSN:0021-9541    

DOI:10.1002/jcp.1041290407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0021-9541    

DOI:10.1002/jcp.1041290408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0021-9541    

DOI:10.1002/jcp.1041290409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0021-9541    

DOI:10.1002/jcp.1041290410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractStudies on the relevance of the N‐nitrosamines to esophageal cancer in China are reviewed. Esophageal cancer is a complex and multifactorial problem. Although a causal association between nitrosamines exposure and esophageal cancer in China has not yet been rigorously established, exposure of Lin‐Xian subjects to nitrosamines either directly or as a result of their in vivo formation has been detected in our study.Several N‐nitrosamines (NDMA, NDEA, NMBzA, NPyr, NPip, and NSAR) in gastric juice collected from Lin‐Xian inhabitants have been detected. A correlation was found between the lesions of esophageal epithelium and the amount of nitrosamines present. In addition, the amounts of N‐nitrosamino acids (N‐nitrosoproline, N‐nitrosothiazolidine 4‐carboxylic acid, NSAR, and nitrates) excreted in 24‐hr urine of subjects in Lin‐Xian were significantly higher than those in Fan‐Xian, indicating a higher exposure to N‐nitroso compound and their precursors of the inhabitants in the high‐risk area.The effect of nitrosamines on human esophagus has been investigated at the cellular levels. The amounts of O6‐MedG in DNA of esophageal or stomach mucosa of patients from Lin‐Xian were higher than that from Europe (Lyon and Essen). The presence of O6‐MedG in the human fetal esophagus cultured with NMBzA was also detected. These findings indicate that the elevated levels of O6‐MedG in esophageal DNA could be the result of a recent exposure to N‐nitroso compounds or a genetically determined reduced cellular capacity for repair of O6‐MedG from DNA.The hyperplasia was induced in the esophagus of human fetus that cultured with NMBzA for 2 weeks to 2 months.The intervention studies of esophageal cancer in Lin‐Xian have been pursured. Intake of moderate doses of ascorbic acids by Lin‐Xian subjects effectively reduced the urinary levels of N‐nitrosamino acids to those found in undosed subjects in the low‐risk area. If N‐nitroso compounds are formed in vivo and are among the causative factors of esophageal cancer in Lin‐Xian, ascorbic acid appears to be effective in lowering the body burden of these carcinogenic compounds. Thus, the p

ISSN:0021-9541    

DOI:10.1002/jcp.1041290411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractMale Fischer F344 rats (180–220 g) were fed either a basal diet, a diet supplemented with 2‐acetylaminofluorene (AAF) 0.02% (w/w) for up to 3 months or dietary tumor promoters. Normal or AAF‐altered hepatic microsomes were compared with respect to drug‐induced lipid peroxidation. A three‐fold decrease was found in the ability of adriamycin to induce lipid peroxidation on AAF‐altered and promoter‐altered microsomes, compared to normal microsomes. A similar decrease was found when using a direct acting organic peroxidant. The microsomal hepatic lipid was extracted, and AAF‐altered lipid was found to be a poorer substrate for adriamycin‐mediated lipid peroxidation compared to normal microsomal lipid. Similar results were obtained with purified phosphatidylcholine from AAF‐altered compared to normal microsomes. It was concluded that carcinogen treatment causes alterations in the microsomal phospholipids that render them less susceptible to lipid peroxidation, which is probably due to a carcinogen‐induced decrease in the level of

ISSN:0021-9541    

DOI:10.1002/jcp.1041290412

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY