[Use of Hoechst fluorescent probe 33258 for quantitative analysis of intracellular binding of anthracycline antibiotics to DNA]. / Ispol'zovanie fliuorestsentnogo zenda Khekhsta 33258 dlia koli- chestvennogo opredeleniia sviazyvaniia antratsiklinovykh antibiotikov s DNK v kletkakh.

The paper deals with development of a procedure for quantitative determination of the share of anthracycline antibiotics bound in cells directly to DNA. A DNA-specific Hoechst fluorescence dye 33258 was used for the purpose. The level of its quenching on DNA correlated with the quantity of the antibiotic bound to it. It was shown that the quenching of the Hoechst fluorescence dye bound to DNA was not due to the dye competition with the antibiotic for the site of bounding on DNA, as was suggested earlier. It was likely to be defined by reabsorption of the radiation by antibiotic molecules.

[Comparative accumulation of the Hoechst 33258 fluorescent probe in leukemia P388 cells sensitive and resistant to doxorubicin]. / Issledovanie sravnitel'nogo nakopleniia fliuorestsentnogo zonda Khekhst 33258 v kletkakh leikoza P 388, chuvstvitel'nykh i ustoichivykh k doksorubitsinu.

The authors studied accumulation of the fluorescent probe Hoechst 33258 in leukemia P 388 sensitive (P 388/0) and resistant to doxorubicin (P 388/DOX) cells. It was shown that intensity of fluorescence of the dye increased after binding with nuclear DNA during 25 min for both lines of the cells. Intensity of fluorescence was 40% greater in sensitive than resistant cells. If Triton X-100 was added no difference between two lines of the cell was observed. When doxorubicin was added to the cells with dye, the intensity of fluorescence decreased. It was suggested to use Hoechst 33258 for assessment extent doxorubicin accumulation in nuclei of the cells.