Action of UV excimer laser radiation and fast neutrons on DNA and chromatin proteins of tumour cells

We studied the action on DNA and chromatin proteins from Walker rat tumours of a laser radiation with λ = 248 nm, from an excimer laser, model 1701 - Physical Institute Moscow (0.5-3 MJ/m2 doses) and of a fast neutron beam, produced at the IAP Cyclotron in Bucharest (d(13 MeV) + Be thick target) (5-100 Gy doses). The DNA modifications were established by thermal transitions and by fluorescence properties of complexes with ethidium bromide. The action on chromatin proteins was evaluated by intrinsic fluorescence and by gel electrophoresis. The modifications produced are dose dependent and characteristic of laser radiation and fast neutrons. The complex action includes: the production of DNA strand breaks, protein destruction and chromatin conformation modifications. (Author)