Cesarone Cf

Improved microfluorometric DNA determination in biological material using 33258 Hoechst

Abstract A simple and rapid microfluorometric method is described for the determination of DNA in submicrogram quantities using 33258 Hoechst fluorochrome. A high degree of reproducibility was obtained using calf thymus and phage DNA, mouse liver chromatin, and HeLa cells homogenate preparations. None or very little interference by the routinely used preparation reagents or by the cellular components was found. Compared to other commonly used procedures this innovative and versatile technique can be conveniently applied to DNA microdetermination for the high sensibility/reproducibility ratio and can also be used without the need of previous purification steps.

Evaluation of damage to DNA after in vivo exposure to different classes of chemicals

Swiss CD1 male mice were injected intraperitoneally (i.p.) with compounds belonging to different chemical classes in order to investigate the influence of those chemicals on the in vivo production of single-strand DNA-breaks in liver and kidney. DNA damage was evaluated by the alkaline elution technique coupled with a microfluorometric method for DNA assay. An increased elution rate was obtained after in vivo treatment with known carcinogens. Our results are in good agreement with the data obtained by long-term carcinogenicity tests and less with those obtained by mutagenicity assays.

DNA damage induced in vivo in various tissues by nitrochlorobenzene derivatives

Mono-, di-, and trinitrochlorobenzenes were injected i.p. into albino Swiss CD1 mice. Their effects were evaluated, in brain, liver and kidney, as single-strand DNA breaks. DNA damage was recognizable 4 h after administration in vivo, and its increment seemed to be related to the number of nitro groups contained in the chlorobenzene molecule. The simple and accurate microfluorometric procedure for DNA assay associated to the alkaline elution technique improved the application in vivo, avoiding the radiolabeling of DNA.