Carcinogenic agents

The experiments with deuterium-labeled nitrosamines illustrate two important points. One is that oxidation of nitrosamines takes place at more than one position in the molecule, and the outcome of the balance of such competing reactions probably is the determinant of carcinogenic potency. The second is that the reason for the failure of carcinogenesis to be mirrored in many cases by the microsomally activated bacterial mutagenicity is that there can be several metabolic steps leading to formation of the proximate carcinogenic agent and not all of these need necessarily involve microsomal enzymes. ... 

Control of N-nitroso compounds as carcinogenic agents so far has rested on agents that can block their formation. It is the intent of this paper to briefly review some of the studies which have been performed on the use of blocking agents to prevent N-nitroso compound formation and describe some recent observations on the mechanism by which these agents function. 

Perchellet, E.M., Abney, N.L. and Perchellet, J.-P. (1988). Stimulation of hydroperoxide generation in mouse skin treated with tumor-promoting or carcinogenic agents in vivo and in vitro. Cancer Lett. 42, 169-177. 

Carcinogenic agents include chemicals in the environment, such as aniline and benzene, which are associated with the development of bladder cancer and leukemia, respectively. Environmental factors, such as excessive sun exposure, also may result in cancer. Viruses, including the human papilloma virus and hepatitis B, maybe associated with the development of cancer. Some of the chemotherapy agents cause secondary cancers after therapy has been completed. Numerous factors may contribute to the development of cancer. 

Radon 222 and its decay products, Rn-d, are well known as among the most powerful carcinogenic agents to which human beeings are exposed as members of the general public (e.g. indoor exposure), as a consequence of occupation (e.g. uranium miner) or as part of... 

Couch, J.A. and J.C. Harshbarger. 1985. Effects of carcinogenic agents on aquatic animals an environmental and experimental overview. Jour. Environ. Sci. Health, Part C, Environ. Carcin. Rev. 3 63-105. 

Cancer is a condition characterized by the uncontrolled replication and growth of the body s own cells (somatic cells). Carcinogenic agents may be categorized as follows ... 

Pliss, G.B. and Khudoley, V.V. Tumor induction by carcinogenic agents in aquarium fish. J. Matl. Cancer Inst. (1975) 55, 129-136. 

Petrun, A.S. and Rubenchik, B.L. (1966). On the possibility of appearance of the carcinogenous agent 3,4-benzpyren in electrostatically smoked fish, Vrachebnoe Delo, 2, 93-95. 

The supposition that ozone is mutagenic or carcinogenic in man is based primarily on information on the biochemical mechanism of ozone toxicity and to a lesser extent on in vitro and animal studies. The biochemical evidence is for the most part indirect and depends on an analogy between the free-radical nature of ozone toxicity and of radiation and other carcinogenic agents. 

Shishodia S, Majnmdar S, Banerjee S, Aggarwal BB. (2003) Ursolic acid inhibits nnclear factor-kappa B activation indnced by carcinogenic agents throngh snppression of Ikappa Balpha kinase and p65 phosphorylation Correlation with down-regnlation of cyclooxygenase 2, matrix metalloproteinase 9, and cyclin Dl. Cancer Res 63 4375 383. 

Tokiwa H, Nakagawa R, Horikawa K. 1985. Mutagenic/carcinogenic agents in indoor pollutants The dinitropyrenes, generated by kerosene heaters and fuel gas and liquefied petroleum gas burners. Mutat Resl57(l) 39-47. 

In a population of sinter plant workers, the risk of death from cancer of the lung or nose has not been shown to decrease even 30-40 years after the workers left the sinter plant (Muir et al. 1994). Although the workers left the sintering operation, many were still exposed to nickel compounds, in operations that have not been associated with cancer. The investigators note that persisting nickel deposits could act as carcinogenic agents. 

Toxic and carcinogenic agents in dry NT610 and moist snuff. J Nat Cancer Inst 1987 79(6) 1281-1286. 

Scientists were faced with formidable experimental challenges in trying to determine which compounds were responsible for this biological activity. Not only are they present in trace amounts and in chemically very complex mixtures of airborne POM, but in vivo animal assays for suspected new genotoxic and carcinogenic agents were then, and remain, time-consuming, labor intensive, and expensive. 

Further discoveries of consumer and industrial products contaminated with N-nitroso compounds (11) led to the speculation that industrial workers that either use or manufacture these products may be exposed to significant amounts of these carcinogenic agents. These discoveries of environmentally occurring N-nitroso compounds plus increased understanding of the mechanism by which they can be formed from their widely available precursor amines (12) and oxides of nitrogen (13), has resulted in this study of worker... 

Models with genetically induced sensitivity to oncogenic transformation serve as sensitive indicators of carcinogenic agents. 

Group D Not classifiable as to human carcinogenicity Agents with inadequate human and animal evidence of carcinogenicity or for which no data are available... 

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