[Experimental studies on tumorigenic activity of cigarette smoke condensate on mouse skin. V. Comparative studies of condensates from different modified cigarettes (author's transl)].

The tumorigenic effect of smoke condensates from reference cigarettes and different modified cigarettes has been investigated on the mouse skin. The following results have been obtained: 1. Reconstituted tobacco sheets made from the blend of the reference cigarette T as well as different other tobacco mixtures showed a reduced tumorigenic effect. 50% or 20% of reconstituted tobacco sheets as additive to the tobacco T showed reduced tumorigenic effect too. 2. A dark tobacco mixture (cigar type) as well as the Virginia tobacco of the mixture T showed no significant differences in biological activity compared to the reference tobacco. Condensate of the Burley tobacco of the blend T showed a reduced tumorigenic effect. 3. A small amount of nitrate as additive (1.8% total nitrate) only showed a limited reduction of the tumorigenic effect. 4. Condensate of a cigarette with commercially used filters, 20% reconstituted tobacco sheets and a total nitrate content of 1.8% showed a distinctly reduced tumorigenic effect. 5. Statistical evaluations of this experiment indicated that each of the applied dose should not be too high. Application of high doses did not lead to a further increase of tumor incidence. Cytotoxicity and viscosity of higher concentrated solutions may be responsible for this fact.