[Direct fluorimetric determination of the DNA content in human leukocyte homogenates]

A simple and highly sensitive method was suggested for fluorometric determination of DNA content in human blood leukocytes. The method is based on the ability of fluorochrome bisbenzimide to bind specifically to DNA of cell homogenates in the presence of 2.5 M NaCl. This method makes it possible to do without preliminary treatment of cell homogenates aimed at the destruction of RNA and proteins, having a strong effect on the fluorescence of DNA complexes with other specific dyes. The technique was used to determine DNA amount in human blood leukocytes of 15 healthy people 23 to 47 years old (8 women and 7 men). DNA content averaged 7.4 +/- 0.35 pg/cell. The minimum detectable DNA concentration was 0.02 micrograms/ml.