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1990
Journal Article
Titel
Comparative carcinogenicity of cigarette mainstream and sidestream smoke condensates on the mouse skin.
Abstract
The direct carcinogenic effects of sidestream (SS) and mainstream (MS) smoke condensates of a filtered commercial brand of blond cigarette were compared using a lifetime mouse skin tumorigenicity assay on female NMRI mice. Each cigarette was smoked by a smoking machine under the standard conditions, and the seperate collected SS and MS smoke condensates were extracted with acetone/methanol as described elsewhere. These were tested for carcinogenicity on a area of 1-1.5 cm shaved skin of mice on the lower back.The mice were treated with half of each dose (5, 10 or 15 mg) twice a week, for only 3 months. No substance was used as promoter or as an additional initator of carcogenicity. No statistically significant difference was found when the life span of MS-treated and untreated animals were compared. In contrast the life span of SS-treated mice were significantly (P<0.01) shorter than those of MS-treated animals or those of all three negative control groups together. The observed carcin ogenic effects were based on tumours and lesions found only on the site of application of the test material. Of 210 mice (effected number,129) serving as the negative controls, 3 developed skin lesions but no tumours. Of 210 MS-treated mice (effective number, 177), 7 developed tumours (4 malignant and 3 benign) and 35 had a uniform type of precancerous skin lesion. The initiation of these latter lesions was found to be dose-dependent (P<0.001). The SS-treated animals developed two to six times more skin tumours than the MS-treated mice. Comparing the negative controls with the MS- or SS-treated animals, the overall carcinogenic effect observed was statistically significant. Comparing the MS- with the SS-treated animals, the overall carcinogenic effect of SS was much higher than that of MS (P<0.001).