Nucleophiles react with the α-acetoxy derivative of α-hydroxybenzylbenzylnitrosamine at the carbonyl carbon of the acetoxy moiety followed by fragmentation to the very same intermediates formed by oxidative metabolism. Since α-acetoxybenzylbenzylnitrosamine has been shown to be able to acylate nucleophiles and since the nucleic acids are nucleophiles, then it is possible that this compound may cause mutations by an acylation pathway instead of or in addition to the more common alkylation pathway. The data in Part I of this dissertation should be considered in any further biological investigations of N,N-dialkylnitrosamine induced mutagenesis or carcinogenesis. The study of the synthesis, reactions, mutagenicity, and the possible correlation to compound liposolubility of cyclic N-nitrosamines was also investigated.

Thesis (Ph. D.)--University of Hong Kong, 1975.

No description available.

Thesis (Ph. D.)--Illinois State University, 1993. / Title from title page screen, viewed March 10, 2006. Dissertation Committee: Alan J. Katz (chair), Herman E. Brockman, David F. Weber, Brian J. Wilkinson, Marjorie A. Jones. Includes bibliographical references (leaves 146-159) and abstract. Also available in print.

M.Sc. / The disinfection of drinking water is an important step in the water treatment process. However, toxic (unwanted) disinfection by-products (DBPs) are often produced during the disinfection of drinking water. One such group of DBPs are the nitrosamines such as N-Nitrosodimethylamine (NDMA). Nitrosamines, particularly NDMA, are highly carcinogenic, mutagenic and teratogenic. The US Environmental Protection Agency (USEPA) placed these compounds into the group B2, which indicates compounds of probable human carcinogens. The USEPA integrated risk information system (IRIS) database lists an estimated 10-6 lifetime cancer risk level for NDMA in drinking water of 0.7 ng/L. The formation of NDMA during drinking water disinfection, particularly chloramination, has been linked to the formation of NDMA through a reaction between monochloramine and organic nitrogen precursors via unsymmetrical dialkylhydrazine intermediates, such as unsymmetrical dimethylhydrazine (UDMH). UDMH is oxidized by dissolved oxygen to form NDMA. Therefore, it is also crucial to remove NDMA precursors (UDMH and dimethylamine (DMA)), before disinfection is carried out. Also, the chlorination of secondary wastewater can result in the formation of NDMA. In this research project, determination of nitrosamines, especially NDMA was done at four different water treatment plants in South Africa. Water samples collected from Midvaal, Sedibeng, Magalies (Vaalkop and Klipdrift) and Rand Water treatment plants were qualitatively analysed for the presence of NDMA. Also, the determination of possible NDMA precursors such as dimethylamine and UDMH was investigated in water samples collected from Sedibeng water treatment plant. The water samples were collected before and after each drinking water treatment process (coagulation, sedimentation, filtration, chlorination and chloramination or ozonation). Solid phase microextraction (SPME) was employed in the extraction of the water samples. Polydimethylsiloxane/divinylbenzene (PDMS/DVB) proved to be the most efficient fibre for the SPME extraction procedure. The water samples vi were then qualitatively analysed using gas chromatography-mass spectrometry (GC-MS). Very small amounts of NDMA were detected in water samples collected from Sedibeng water treatment plant. There was no detectable presence of NDMA or other nitrosamines in water samples collected from the other treatment plants. Water-insoluble cyclodextrin (CD) polyurethanes were then used to ascertain how much of the NDMA they would remove. The CD polymers showed capacity to remove NDMA and dimethylamine (which is a known NDMA precursor) in the water samples with 80% removal efficiency for NDMA (when comparing peak area before and after treatment with CD polymers) and approximately 98% removal rate for DMA.

The induced circular dichroism (ICD) of several chiral nitrosamines and various chiral reagents has been investigated. The interaction is attributed to a 1:1 hydrogen bonded complex between the NO group of the nitrosamine and the hydroxyl groups of alcohols and polyols, or the amino group of amines. Only those chiral reagents possessing large differences in size of the groups about the hydrogen bonding site contributed to CD anomalies. The acyclic 2-octanols did not give observable Cotton effects, presumably due to the similarity in size of the methyl and methylene groups and rotational freedom of the acyclic system. The signs of the Cotton effects could be correlated with the absolute configuration of the sterically hindered alcohols and amines. Only the alpha, axial hydrogens of conformationally biased, heterocyclic nitrosamines were found to undergo selective hydrogen-deuterium exchange, suggesting that this feature is critical for nitrosamine carcinogenicity.

Two aspects of the biological activity of N-nitrosamines were studied. First, the effect of ascorbate on the mutagenicity of N-nitrosopiperidines was studied in the Ames Salmanella/ mammalian microsome mutagenicity test. The addition of ascorbate significantly enhanced the mutagenicity of these compounds. This enhancement was selective for N-nitrosamines suggesting a possible role of ascorbate in N-nitrosamine induced carcinogenicity. Second, the technique of velocity sedimentation in alkaline sucrose density gradients was applied to the detection of N-nitrosamine induced DNA damage in Balb/c 3T3 cells. This technique detected N-nitrosamine induced DNA damage when the cells were made permeable before treatment. This technique compares favorably with other test systems used to evaluate N-nitrosamines and should be useful in further studies of N-nitrosamines.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 148-155). Also available on the Internet.