Thesis (M.S.)--Virginia Polytechnic Institute, 1953. / Vita. Includes bibliographical references (leaves 53-55). Also available via the Internet.

Thesis--Copenhagen. / "Translated from Danish by Hans Andersen." Bibliography: p. [156]-158.

Temperature influences the incidence of chemically induced cancer in fish, with warmer temperatures being associated with higher cancer incidence. The mechanisms of temperature-modulated chemical carcinogenesis in fish, however, have not been described in detail. Therefore, one primary objective of this study was increased understanding of how temperature-modulated genotoxicity of 7,12- dimethylbenz(a)anthracene (DMBA) corresponded with tumor response. The second entails the potential of temperature to modulate cancer promotion. Rainbow trout (Oncorhyncus mykiss) (2 g) were acclimated at 10, 14 or 18��C for one month and then exposed to 1.0 ppm DMBA in their water for 20 hr. Exposures were at respective acclimation temperatures or 10 and 18��C acclimated fish were shifted to 14��C for DMBA exposures. Adduction of [��H]DMBA to hepatic DNA 21 days after exposure was higher in 10��C than 18��C fish exposed at their respective acclimation temperatures. However, in fish shifted to 14��C, the concentration of hepatic [��H]DMBA DNA adducts was similar in 10��C and 18��C acclimated fish at that time. Temperature effects on tumor incidence were assessed 9 months after DMBA waterborne exposures. Incidence of stomach, liver and swim-bladder cancer increased with rearing temperature. Differences in tumor incidence were less marked in fish reared at the same temperature (14��C). Retrospective analyses of livers from a tumor study initiated with aflatoxin B1 (AFB1) was conducted with antibodies to endogenous proliferating nuclear antigen (PCNA). Proliferating cells were scored by counting labeled nuclei in 5 random 10x fields using an image analysis program (BIOQUANT SYSTEM IV). There was no significant increase in numbers of PCNA labeled hepatocytes with temperature. The influence of acclimation temperature on plasma mitogens that stimulate cell division was assessed in cultured Chinook salmon embryo cells (CHSE-214). Plasma from rainbow trout (120-150 g) acclimated to either 10 or 18��C for at least four weeks stimulated in vitro proliferation of CHSE-214 cells to the same extent. This study demonstrated that chemically induced tumors in fish were modulated by temperature not only through genotoxin disposition and formation but also through persistence of DNA adducts. It also discounted the role of mitogenesis in temperature-modulated chemical carcinogenesis. / Graduation date: 1996

In the study of the cyclodehydrogenation of 12-(3-methylphenyl)benz[a]anthracene, Zajac pointed out that the hydrocarbon might undergo ring closure at either of the ortho positions of the phenyl ring. These positions are not equivalent with respect to the methyl group and ring closure might yield either 2-methyl dibenzo[a,l]pyrene or 4-methyldibenzo[a,l]- pyrene or a mixture of both isomers. When the compound, 12-(J-methylphenyl)benz[a]-anthracene, was dehydrogenated only one isomer was isolated. The isomer which was isolated could be either of the two possibilities. Therefore, it was decided to synthesize 2-methyldibenzo[a,l]pyrene unequivocally. By comparing the physical properties of the compound synthesized unequivocally with those of the compound from the cyclodehydrogenation of 12-(3-methylphenyl)benz[a]anthracene it can be determined which isomer was isolated by Zajac. Therefore, 12-{ 2-chloro-5-methylphenyl)benz[a]-anthracene was synthesized; this compound could then be cyclodehydrohalogenated to the corresponding 2-methyldibenzo[a,l]]pyrene. Using potassium hydroxide-quinoline and alkoxides led only to the recovery of starting material or to the destruction of it, depending on whether the reaction conditions were mild or drastic. Aluminum chloride destroyed the starting material in reaction time as short as five minutes. Stannic chloride destroyed only part of the starting material. An aluminum chloride-stannic chloride mixture also destroyed the starting material. In none of the experiments mentioned could the presence of 2-methyldibenzo[a,l]pyrene be detected. Although the right conditions for the cyclodehydrohalogenation were not found, the data obtained during the gas chromatographic studies are very valuable because it can be used for the other phases of the work being done in This Laboratory. / Master of Science

It is the purpose of this thesis to further investigate the reaction suggested by Bradsher, and the preparation of some 10-dimethly-phenyl-1, 2-benzanthracenes. / Master of Science

Ph. D.

Ph. D.

Many benz(a)anthracene derivatives are able to produce cancer in the experimental animal. There is a correlation between the calculated total electronic charge of the K-region and this carcinogenic activity. There is also ample proof that benz(a)anthracene derivatives are honed to the skin through quinoid type bonds in the K"region. However, the prediction of physiological activity of benz(a)anthracenes is still unreliable because of the limitations of the theoretical model described by existing theories. The purpose of this work was to synthesize some substituted benz(a)anthracenes with a shielded K-region and with a different L-region electron density than in 7-phenyl-bena(a)anthracene in the hope of increasing our knowledge regarding molecular structure-physiological relationship. / Ph. D.

The ayelodehydrogenation of 7-(1-naphthyl)benz [a] anthracene to dibenzo [a,e] perylene was accomplished in 38% yield using an aluminum chloride - stannic chloride catalyst. Attempts to reproduce or to improve this yield were not successful and thereafter the only product isolated was a low melting light orange solid which was postulated to be a hydrogenated intermediate. That the orange material could be converted to dibenzo [a,e] perylene upon treatment with palladiem on charcoal in p-eymene substantiated this postulation. / Master of Science

The structures of the six new compounds and the TNF molecular complex were substantiated by satisfactory elemental analyser. The infrared and ultraviolet absorption spectra of the six new compounds were recorded. / Master of Science