Bleomycin, in contrast to gamma irradiation, induces extreme variation of DNA strand breakage from cell to cell.

Chinese hamster ovary cells grown in vitro were treated with bleomycin or irradiated with high doses of 60Co gamma rays (200 and 400 Gy). DNA strand breaks in single cells were analysed by using our newly introduced microelectrophoretic technique. Bleomycin seems to act in a selective manner so that in some cells the DNA is heavily degraded while in others there is only moderate or no measurable damage.

DNA damage in clinical radiation therapy studied by microelectrophoresis in single tumour cells. A preliminary report.

Aspiration biopsy specimens were taken from malignant tumours--1 Hodgkin's lymphoma, 3 non-Hodgkin lymphomas, 1 squamous cell carcinoma and 1 adenocarcinoma-before and after irradiation. Individual cells were analysed by micro-electrophoresis, a new technique which estimates radiation-induced DNA strand breaks. The cells were embedded in agarose gel; after lysis of the cells in a neutral detergent solution, an electric field (5 V/cm) was applied for five minutes.

Microelectrophoretic study of radiation-induced DNA damages in individual mammalian cells.

Mammalian cells were after irradiation suspended in melted agarose, and casted on microscope slides. The slides were after gelling at 0 degree C immersed in a neutral detergent solution which lysed the cells. A weak electric field (5 V/cm) was then applied over the gel for 5 minutes.