We previously observed that postnatal exposure of mice to the procarcinogen 4-aminobiphenyl (ABP) produced liver tumors only in wild-type males, while arylamine N-acetyltransferase deficient males and females of either strain were protected. Others have also observed a sex difference in liver tumors in mice using the procarcinogen diethylnitrosamine (DEN). Reasons for these sex and strain differences are unclear, but differences in acute hepatotoxicity and inflammation may be involved. In this thesis we found that neither ABP nor DEN produced overt hepatotoxicity in postnatally exposed mice, and only DEN caused an increase in levels of the pro-inflammatory cytokine interleukin-6 but was not sex-dependent. The lack of sex difference suggests that sex hormone modulation of inflammation following sexual maturation might favour growth of initiated cells in males. However, the lack of detectable inflammation following ABP exposure may be due to localized responses, or that inflammation may be a DEN-specific effect.

We previously observed that postnatal exposure of mice to the procarcinogen 4-aminobiphenyl (ABP) produced liver tumors only in wild-type males, while arylamine N-acetyltransferase deficient males and females of either strain were protected. Others have also observed a sex difference in liver tumors in mice using the procarcinogen diethylnitrosamine (DEN). Reasons for these sex and strain differences are unclear, but differences in acute hepatotoxicity and inflammation may be involved. In this thesis we found that neither ABP nor DEN produced overt hepatotoxicity in postnatally exposed mice, and only DEN caused an increase in levels of the pro-inflammatory cytokine interleukin-6 but was not sex-dependent. The lack of sex difference suggests that sex hormone modulation of inflammation following sexual maturation might favour growth of initiated cells in males. However, the lack of detectable inflammation following ABP exposure may be due to localized responses, or that inflammation may be a DEN-specific effect.

Amino derivatives of polycyclic aromatic hydrocarbons are well-known chemical carcinogens which should be carefully monitored in our environment. They are amenable to anodic oxida- tion on suitable solid or paste electrodes. This fact was exploited for voltammetric determina- tion of 4-aminobiphenyl on unmodified carbon paste electrode and carbon paste electrodes modified by montmorillonite and sepiolite. The optimum pH of BR buffer for measurement on unmodified carbon paste electrode is pH 2, pH 10 for CPE-SEP and pH 11 for CPE-MMT. It was possible to increase sensitivity of the determination using adsorptive stripping voltam- metry on modified electrodes. The optimum time for accumulation of 4-aminobiphenyl is 5 minutes. The limits of quantification of the order of 10−6 mol dm−3 were obtained for each electrode. After accumulation, the limits of quantification decreased to the 10−7 mol dm−3 . The newly developed method was tested for the determination of 4-aminobiphenyl in model sam- ples of drinking and river water, reaching limits of quantification of the order of 10−7 mol dm−3 .

No description available.

Recent studies from our laboratory on the aromatic amine carcinogen, 4-aminobiphenyl (ABP) have shown a significantly lower prevalence of ABP-induced liver tumors in male mice lacking the N-acetyltransferases, and a dramatically lower prevalence in females than in males, but no association of tumor prevalence with strain or sex differences in levels of acute ABP-induced DNA damage. This thesis aimed to investigate the possible involvement of acute cytotoxic effects of ABP in the development of a tumor-promoting inflammatory environment. We found that wild-type male mice showed higher acute hepatotoxicity to ABP, as well as, a possible trend towards higher serum levels of the pro-inflammatory cytokine interleukin 6. This correspondence between acute ABP cytotoxicity and inflammatory response with ultimate tumor growth is consistent with a model whereby ABP not only initiates cells by damaging DNA but also promotes tumor growth in a gender-selective fashion that may be governed by gonadal hormone influences.

Recent studies from our laboratory on the aromatic amine carcinogen, 4-aminobiphenyl (ABP) have shown a significantly lower prevalence of ABP-induced liver tumors in male mice lacking the N-acetyltransferases, and a dramatically lower prevalence in females than in males, but no association of tumor prevalence with strain or sex differences in levels of acute ABP-induced DNA damage. This thesis aimed to investigate the possible involvement of acute cytotoxic effects of ABP in the development of a tumor-promoting inflammatory environment. We found that wild-type male mice showed higher acute hepatotoxicity to ABP, as well as, a possible trend towards higher serum levels of the pro-inflammatory cytokine interleukin 6. This correspondence between acute ABP cytotoxicity and inflammatory response with ultimate tumor growth is consistent with a model whereby ABP not only initiates cells by damaging DNA but also promotes tumor growth in a gender-selective fashion that may be governed by gonadal hormone influences.