Carcinogenicity studies, polycyclic

The carcinogenicity of polycyclic aromatic compound-rich tyre extender oils has lead to the proposal of a legislative ban on their use in Europe. The suitability of naphthenic oils as non-toxic plasticisers in tyre treads is discussed and results are presented of experimental studies of the use of these plasticisers in SBR, EPDM, sulphur-cured EPDM and peroxide-cured EPDM. Despite their low aromatic content, the naphthenic plasticisers are shown to give good results in SBR, probably as a result of the contribution to solvent characteristics of the naphthenic molecular structure. The use of naphthenic oils is expected to increase worldwide as they are said to be one of the best alternatives to aromatic extracts with regard to solvent properties, compatibility, performance and availability. 

Menichini, E., Monfredini, F., Merli, F., 1999. The temporalvariability of the profile of carcinogen ic polycyclic aromatic hydrocarbons in urban air A study in a medium traffic area in Rome, 1993-1998. Atmos. Environ. 33, 3739-3750. 

These analyses show major differences in the DNA reaction products formed by DMBA and by BP, a weaker but much more extensively studied polycyclic aromatic hydrocarbon carcinogen (35). 

Norden, B., Edlund, U., and Wold, S., Carcinogenicity of polycyclic aromatic hydrocarbons, studied by SIMCA pattern recognition, Acta Chemica Scandinavica Series B, 32, 602-608, 1978. 

The Pullmans were the first to use electronic structure calculations in several studies on the carcinogenicity of polycyclic aromatic hydrocarbons and hetero analogs in the late 1940s and early 1950s. Much of the early work on... 

Summary of Carcinogenicity Studies with Polycyclic Aromatic Hydrocarbons Using Parenteral Routes of Exposure... 

Yuan, M. and Jurs, P. C. (1980) Computer-assisted stmcture-activity studies of chemical carcinogens a polycyclic aromatic hydrocarbon data set. Appl. Pharmacol., 52, 294-312. 

Des., 1, 115-133 (2002). QSAR Carcinogenic Study of Methylated Polycyclic Aromatic Hydrocarbons Based on Topological Descriptors Derived from Distance Matrices and Correlation Weights of Local Graph Invariants. 

Oxidation is intimately linked to the activation of polycyclic aromatic hydrocarbons (PAH) to carcinogens (1-3). Oxidation of PAH in animals and man is enzyme-catalyzed and is a response to the introduction of foreign compounds into the cellular environment. The most intensively studied enzyme of PAH oxidation is cytochrome P-450, which is a mixed-function oxidase that receives its electrons from NADPH via a one or two component electron transport chain (10. Some forms of this enzyme play a major role in systemic metabolism of PAH (4 ). However, there are numerous examples of carcinogens that require metabolic activation, including PAH, that induce cancer in tissues with low mixed-function oxidase activity ( 5). In order to comprehensively evaluate the metabolic activation of PAH, one must consider all cellular pathways for their oxidative activation. 

Yan, L.S. 1985. Study of the carcinogenic mechanism for polycyclic aromatic hydrocarbons — extended bay region theory and its quantitative model. Carcinogenesis 6 1-6. 

Sforzolini, G.S., Saviano, A., and Merletti, C. The action of chlorine on some hydrocarbons, polycyclic hydrocarbons, contributing to the study of the decontamination of water from carcinogenic compounds. Bull. Soc. Ital. Biol. Sper., 46 903-906, 1970. 

Earlier progress in these studies has been summarized in reviews published in the last decade, emphasizing carbocations and oxidation dications, RCs, as well as reactive intermediates from the nitro- and nitroso-derivatives. The review article published in 1996 emphasized groundwork studies on protonation as well as oxidation (both RCs and stable dications) of polycyclic arenes and explored possible relationships between charge distribution and carcinogenicity, in concert with its... 

When studying the carcinogenic activity of polycyclic hydrocarbons and their antdogs containing thiophene rings (cf. Tilak "), Tilak et al synthesized both thienothiophene 1 and its isomer 2 in low yield from 2-thienyl dimethoxyethyl sulfide (23) and 3-thienyl diethoxyethyl sulfide (24), respectively, by the method developed for synthesis of thiophenes and thiopyrans - [Eqs. (10) and (11)]. The compounds 23 and 24 were prepared from 2- and 3-mercaptothiophenes. ... 

There are almost no data available concerning the pharmacokinetics (i.e., the uptake, distribution, metabolisms, and excretion) of chemical carcinogens in humans. Nevertheless, it is possible to make limited assumptions about the pharmacokinetics of carcinogens, based on the results of animal studies conducted with various chemicals, notably polycyclic hydrocarbons such as benzo[a]p3nene. 

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