[Linear- and Areal-analytical results of the karyometric studies on monolayer cultures and the influence of actinomycin (author's transl)].

Actinomycin D (AMD) inhibits the RNA-synthesis by intercalating with the DNA-helix. In monolayer culture of embryonic mouse brain cells in the 8th passage the cell nuclei were demonstrated with the Feulgen-reaction and quantitatively-morphometrically evaluated following a 48 h intoxication with AMD (0.001; 0.01; 0.1 mug/ml). The mean value of nuclear area calculated from single measurements with the Quantimet 720 is significantly larger when compared to the controls at a dose of 0.01 mug AMD/ml. At 0.1 mug AMD/ml ca. 30% of the cell nuclei are pyknotic; the non-pyknotic nuclei are enlarged significantly by appr. 20%. The linear-analytic results using a Digiscan show no enlargement of tendon length, on the contrary, at 0.1 mug AMD/ml a significant diminution versus the controls can be seen. This resutls from the pyknotic cell nuclei which are also measured in this case no single measurements were carried out. The determination of cell density using a Digiscan shows a diminution of cell number by 19, 31 or 68% dependent upon AMD-concentration.