| Autor: |
Nessel, Craig S., Priston, Robert A. J., McKee, Richard H., Cruzan, George, Riley, Anthony J., Randi, Hagemann, Plutnick, Robert T., Simpson, Barry J. |
| Zdroj: |
Toxicological Sciences; 1998, Vol. 44 Issue 1, p22-31, 10p |
| Abstrakt: |
The role of skin irritation and other factors on the tumorigenic activity of petroleum middle distlllates (PMDs) in mice was examined in a comprehensive research program. The program culminated in a 2-year dermal carcinogenicity study which compared the effects of equal weekly doses of irritating and nonirritating PMDs. Modified Ames mutagenicity studies and three- to seven-ring polycyclic aromatic compound (PAC) analyses indicated that the mutagenic activity of PMDs was correlated to PAC content In subchronic and subacute studies, PMDs produced marked skin irritation which was ameliorated if the test samples were diluted in mineral oil. The reduction in irritation level was not a result of reduced dermal absorption. Straight-run kerosine (SRK), straight-run gas oil (SRGO), and catalytically cracked light cyde oil (LCO) were evaluated in the dermal carcinogenicity study. Test materials were applied either undiluted (2×/week) or as 28.5% (7×/week) or 50% (4×/ week) concentrations in mineral oil for a total weekly dose of 100 μl PMD per animal All three materials produced moderate to marked skin irritation and increased tumor frequency when applied undiluted. When diluted, the irritant effects of SRK and SRGO, which contain low levels of PACs, were ameliorated, and there were no Significant increases in tumors relative to controls. LCO, containing 8 7% three- to seven-ring PACS, increased turnor frequency when diluted, even when skin irritation was limited. These data indicate that the tumorigenic activity of straight-run MDs is likely a consequence of a nongenotoxic process, associated with frequent cell damage and repair. PMDs which contain low levels of three- to seven-ring PACs are unlikely to cause tumors in the absence of prolonged skin irritation. In addition, genotoxic mechanisms may also contribute to tumor formation for other PMDs cantaining higher levels of PACs, e.g., products blended with cracked stocks. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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