Establishment of normal diploid and malignant heteroploid cell lines from non-treated and benzo(a)pyrene treated hamster embryo cell cultures.

Two normal diploid control cell lines and a heteroploid malignant transformed cell line from B(a)P treated hamster embryo cell cultures were established. The 14-month-old B(a)P transformed cell line grew 8-times faster than the 20-month-old control cell line. The control cell line showed normal diploid chromosome complement in 93% cells and heteroploidy in 7% cells while B(a)P treated line showed 83% heteroploid cells and only 17% diploid cells. This is the first report on the establishment of diploid hamster cell cultures grown for extended period.     

Kinetics of the penetration of benzo(a)pyrene and benzo(k)fluoranthene into cells]

Microspectrofluorometric methods have been used to study the kinetics of the increase of fluorescence due to the intake of Benzo(k)Fluoranthène and Benzo(a)Pyrène in single living L cells. A computer program based on the methods of the least square fit has allowed the determination of the kinetic parameters. The results show that pinocytosis cannot be the unique mechanism of intake.     

Effects of benzo(a)pyrene on isolated rat liver mitochondria

Riassunto Viene trattato mitocondri isolati di fegato di ratto con una soluzione acquosa di benzo(a)pyrene. I mitocondri cosi trattati appaiono rigonfi, hanno matrici chiare e notevole aumento degli spazi mannitolo-impermeabili. Queste modificazioni sono verosimilmente dovute all'azione del benzo(a)pyrene sulle molecole fosfolipidiche delle membrane motocondriali.     

The protective effect of Thiola against the genotoxic action of benzo(a)pyrene

The protective effect of Thiola against the genotoxicity, induced by benzo(a)pyrene, in vitro and in vivo, was investigated. By association of Thiola to benzo(a)pyrene a significant decrease of the numerical and structural chromosome aberrations and a reduction of the incidence of c-mitoses has been obtained in human diploid cells, i.e. human embryonic lung fibroblasts of the cell-line ICP-23, and C56B1/6 mouse bone marrow cells.     

The protective effect of thiola against the genotoxic action of benzo(a)pyrene

Summary The protective effect of Thiola against the genotoxicity, induced by benzo(a)pyrene, in vitro and in vivo, was investigated. By association of Thiola to benzo(a)pyrene a significant decrease of the numerical and structural chromosome aberrations and a reduction of the incidence of c-mitoses has been obtained in human diploid cells, i.e. human embryonic lung fibroblasts of the cell-line ICP-23, and C₅₆Bl/6 mouse bone marrow cells.     

Dietary carotenoids block photocarcinogenic enhancement by benzo (a)pyrene and inhibit its carcinogenesis in the dark

The carotenoids beta-carotene (C) and canthaxanthine (CX), with and without pro-vitamin A activity, respectively, when perorally administered to mice, markedly prevent benzo(a)pyrene photocarcinogenic enhancement (BP-PCE), continue to block such BP-PCE and protect significantly against BP carcinogenesis in mice maintained in the dark. These results appear relevant to both the pathogenesis of chemical carcinogenesis and rational programs of skin cancer prevention in humans.     

The effect of cigarette-smoke condensate on the in vitro fixation of benzo(a)pyrene on DNA

Résumé Le condensat de fumée de cigarette induit in vivo, l'aryl hydrolase microsomiale. Il est capable de former avec l'ADN des complexes qui diminuent le taux de fixation ultérieure du B(a)P. Ces résultats montrent qu'il contient des substances différentes du B(a)P et capable d'entrer en compétition avec lui.

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Carcinogenic activation of benzo(a)pyrene by iodine and ferric chloride in the respiratory tract of Syrian golden hamsters

Summary Benzo(a)pyrene (0.5 mg), in itself weakly carcinogenic, when given in combination with ferric chloride (0,16 mg) or iodine (0,2 mg), alone noncarcinogenic, induced a number of tumors of different parts of the respiratory tract of Syrian golden hamsters.Partially supported by Public Health Service contracts PHS 43-68-959 and NO1 CP33278 from the Division of Cancer Cause and Prevention. The authors wish to thank Mrs Virginia Ooten for her technical assistance.     

Long-lasting persistence of elevated sister-chromatid exchange frequencies induced by perinatal benzo(a)pyrene treatment in rat bone-marrow cells

In this work the possibility that a mutagenic factor acting in utero or in the perinatal period might lead to elevated mutagenic rates in bone-marrow cells after a considerable period of time was examined. An aromatic hydrocarbon, benzo(a)pyrene was used as the test substance. Benzo(a)pyrene treatments resulted in significantly higher sister-chromatid exchange (SCE)-frequencies in both fetal and neonatal groups in both sexes, even four months after exposure. In a second experiment we examined whether mutagenic exposure suffered in utero could make the individual more susceptible to mutagenic effects in adulthood. Preliminary results indicate that such a possibility could exist.     

Comparative studies on the covalent binding of the carcinogen benzo(a)pyrene to DNA in various model systems

Summary The covalent binding of tritiated benzo(a) pyrene (BP) to DNA has been determined in rat liver in vivo, in rat liver perfused in situ, after incubation of BP with liver single cells, with liver homogenate, with liver microsomes and DNA, with fibroblasts from a rat granuloma pouch, and with 2 cell lines. Liver single cells were found to be a valuable compromise between the most sensitive system (microsomal incubation of BP with DNA) and the biologically most relevant system (in vivo).Presented in part at the 10th Annual Meeting of the Union of Swiss Societies of Experimental Biology, Experientia34, 925 (1978), abstract.Acknowledgment. We thank Dr G. Kistler, Institute of Anatomy, University of Zurich, for generously supplying the SIRC and VERO cell lines, and Mr P. Manser for the preparation of the granuloma pouch fibroblasts.     

Establishment and characterization of 3 human cell lines derived from intracerebral metastatic tumors]

Twelve human tumors were cultivated in vitro by the trypsinization technique and 3 cell lines were established. Each of these 3 lines showed individual characteristics which were maintained during passages. After inoculation into nude mice, 2 lines induced tumors which possessed the histologic features of the original human tumors (melanoma and carcinoma of stomach), the other line derived from a breast carcinoma was rejected.     

Comparative studies on the covalent binding of the carcinogen benzo(a)pyrene to DNA in various model systems.

The covalent binding of tritiated benzo(a)pyrene (BP) to DNA has been determined in rat liver in vivo, in rat liver perfused in situ, after incubation of BP with liver single cells, with liver homogenate, with liver microsomes and DNA, with fibroblasts from a rat granuloma pouch, and with 2 cell lines. Liver single cells were found to be a valuable compromise between the most sensitive system (microsomal incubation of BP and DNA) and the biologically most relevant system (in vivo).     

Kinetics of decrease and apparent transformation of fluorescence spectra of benzo(a)pyrene absorbed by living cells: case of lymphocytes and macrophages]

A home made microspectrofluorimeter is used in order to follow the decrease of fluorescence intensity of Benzo(a)Pyrene after its absorption by single living cells. The kinetics look to be a first order one; fluorescent metabolite can be detected when peritoneal macrophages of Mice are used but not with human periferic lymphocytes pretreated with mitogens.