[Background Level of γH2AX Foci in Human Cells as a Factor of Individual Radiosensitivity].

The paper analyzes the effects of spontaneous level of yH2AX and 53BP1 foci on a frequency of radiation-induced centromere-negative and centromere-positive micronuclei in peripheral blood lymphocytes of 54 healthy individuals after exposure to 2 Gy of ionizing radiation in vitro. An inverse correlation was found between the level of spontaneous yH2AX foci and the frequency of centromere-negative micronuclei after irradiation. The corresponding correlations between the spontaneous level of protein 53BP1 foci and the frequency of centromere-negative micronuclei were not statistically significant. In addition, cells of the individuals with a high frequency of radiation-induced micronuclei were also characterized by a low proliferative activity. It was suggested that DNA double strand break repair works less efficiently in cells of the individuals with low levels of spontaneous yH2AX foci, and a greater number of DNA double strand breaks after exposure to ionizing radiation remains unrepaired, thus leading to a cell cycle block and an increase of the frequency of centromere-negative micronuclei.

[Ozone therapy for radiation reactions and skin lesions after neutron therapy in patients with malignant tumors].

The article discusses the problem of radiation complications from normal tissues in patients after therapy with fast neutrons of 6.3 MeV. The methods of treatment using ozone technologies in patients with radiation reactions and skin lesions on the areas of irradiation after neutron and neutron-photon therapy have been worked out. Ozone therapy showed its harmlessness and increased efficiency of complex treatment of these patients.

[The use of fast neutrons in treatment of malignant tumors of the head and neck].

The article presents issues of the application of neutron therapy in the combined and radiation therapy for head and neck tumors. There were developed methods of neutron and neutron-photon therapy in pre- and postoperative periods as well as in stand-alone option in unresectable tumors. The data obtained clearly demonstrate the superiority of new ways over standard methods of treatment. Neutron therapy is satisfactorily tolerated and allows improving the results of combined and radiation therapy patients with malignant tumors of the head and neck.

[The clinical course of thyroid cancer following its combined treatment with the use of fast-neutron therapy in the patients at the high risk of relapses].

A few patients presenting with thyroid cancer characterized by the high risk of relapses are reported. Their combined treatment included therapy using fast-neuron with the energy of 6.3 MeV. The immediate and late results of the treatment of the reported cases are evaluated. The experience gained during the study gives evidence of the fairly good tolerability of the described radiotherapeutic modality producing neither acute radiation reactions nor lesions in the irradiated tissues and organs. Moreover, the treatment is described as a highly effective one.

Cytogenetic effects of neutron therapy in patients with parotid gland tumors and relapse of breast cancer.

AIM: To assess the frequency and spectrum of chromosome aberrations and micronuclei in peripheral blood lymphocytes of patients with parotid salivary gland tumors and relapse of breast cancer during the course of neutron therapy. MATERIALS AND METHODS: Samples of peripheral blood were obtained from 9 patients with parotid salivary gland tumors (T3N0-3M0) and 8 patients with relapse of breast cancer before, after first fraction and at the end of neutron therapy. The treatment course specified 5.5-8.4 Gy (equivalent to 23-44 Gy of photon irradiation) with 1.3-2.2 Gy per fraction for patients with parotid salivary gland tumors and 4,8-8.0 Gy (equivalent to 30-40 Gy of photon irradiation) with 1.6 Gy per fraction for patients with relapse of breast cancer. Control group established for conventional cytogenetic analysis consisted of 15 healthy persons. Assessment of chromosome aberrations frequency was performed on routinely stained metaphase plates. Lymphocytes from the same patients were analyzed by micronucleus test in combination with fluorescent in situ hybridization (FISH) using pancentromeric DNA probe. RESULTS: Level of chromosome aberrations and micronuclei significantly increased in lymphocytes of patients from both groups during neutron therapy (P < 0.05). This increase was mainly due to chromosome-type aberrations and centromere-negative micronuclei. The prevalent types of aberrations are in agreement with theoretical mechanisms of neutron effects on cells. CONCLUSION: Cytogenetic effects of fast neutron therapy in lymphocytes of patients with parotid salivary gland tumors and relapse of breast cancer were observed. A positive dynamics of radiation-induced chromosomal damages formation during the course was denoted in lymphocytes of cancer patients in both groups.