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The responses of deoxyribonucleotide (dNTP), DNA and protein synthesis systems in blood-forming organs of animals (dogs, mice) as well as changes in Fe(3+)-transferrin (Fe(3+)-TF) and Cu(2+)-ceruloplasmin (Cu(2+)-CP) pools in blood to gamma-irradiation and the administration of radioprotectors have been studied. It has been shown that changes in Fe(3+)-TF and Cu(2+)-CP pools in blood are indices of changes in the body radioresistance and are reliably controlled by the EPR technique. An increase in the Fe(3+)-TF pool promotes the activated synthesis of dNTP, DNA and Fe(3+)-containing proteins which are essential for the repair efficiency during the early post-irradiation time as well as for the development of compensatory and restorative reactions of cellular systems; i.e., they are responsible for the body resistance to DNA-damaging factors. It is important that the intensity of responses depends on the initial state of the organism. It has been shown, that changes in Fe(3+)-transferrin and Cu(2+)-ceruloplasmin pools, which are trust-worthy controlled by the EPR technique in whole blood, blood plasma, and serum, as well as the changes in the extracellular DNA content in blood plasma are the markers of the changes in the organism radioresistance. This has been proved during the medical examination of the Chernobyl accident recovery workers and civil population, including children, exposed to low-intensity radiation.

The electron-acceptor properties of a number of 5-nitrofuran derivatives containing azomethine, vinylquinoline, and other groups, have been studied, and the parameters of the electronic structure of the radical-anions of these compounds have been established. The radical-anions in solution have been identified from the electronic absorption and EPR spectra. The electronic structure of the radical-anions has been determined from the EPR spectra and the results of quantum-chemical calculations by the INDO method with allowance for the solvation of the nitro-group. The nitro-group is the principal electron-acceptor in the compounds studied. The change in the electron-acceptor properties of the substances studied has been followed from the calculated values of the energies of the lowest unoccupied MO and the nucleophilicity indices c/sub i/*/sup 2/.

It is shown that the low-temperature ESR spectra of γ-irradiated samples of the normal mouse liver, hepatoma and tumor host liver are different. A detailed analysis of the ESR spectra of investigated irradiated tissues was carried out.