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DNA repair is critical for successful chemo- and radiotherapy of human tumours, because their genotoxic sensitivity may vary in different types of cancer cells. In this study we have compared DNA damage and the efficiency of its repair after genotoxic treatment with hydrogen peroxide, cisplatin and γ-radiation of head and neck squamous cell carcinoma (HNSCC). Lymphocytes and tissue cells from biopsies of 37 cancer patients and 35 healthy donors as well as the HTB-43 larynx cancer cell line were employed. The cell sensitivity to genotoxic treatment was estimated by the MTT survival assay. The extent of DNA damage and efficiency of its repair was examined by the alkaline comet assay. Among the examined treatments, we found that HNSCC cells were the most sensitive to γ-radiation and displayed impaired DNA repair. In particular, DNA damage was repaired less effectively in cells from HNSCC metastasis than healthy controls. In conclusion, our results suggest that the different genotoxic sensitivity of HNSCC cells may depend on their DNA repair capacity what in turn may be connected with the effectiveness of head and neck cancer therapy.

Objectives: The aim of the study was to assess the function of semicircular canal in videonystagmography head impulse test (VHIT) in the patients with vertigo and balance disorders. Material and Methods: The study was performed in 135 patients (86 women and 49 men) aged 22-79 years, who were divided into 2 groups: I (study group) -73 patients with vertigo of peripheral, central or mixed origin, II (control group) -62 patients without vertigo (healthy individuals). The function of canal was determined on the basis of GAIN and expressed as DG/RH×100% (where DG is deviation of gaze and RH is rotation of head). Results: In the study group the semicircular canal injuries were found in 37 (50.69%) patients, including 24 (32.87%) patients with 1 injury and 13 (17.8%) patients with 2 or more injuries in semicircular canal. The injured anterior semicircular canal was reported 13 times; the lateral -9 times and the posterior -31 times. Conclusions: In the study group, in the VHIT, injuries in semicircular canals were reported in peripheral vertigo, mixed vertigo with noncompensated and compensated function of the labyrinth in 50.68% cases, whereas in the caloric test dysfunction of the labyrinth was found in 58.49% cases.

The purpose of the paper was to assess the effects of oral contraceptives on selected parameters of the homeostatic control system in women having a sudden disorder of the auditory and/or balance system. The study included 105 young women divided into two groups: Group I—52 women with the disorder of the auditory and/or balance system using hormonal contraceptives for at least 2 months, aged 20–49; and Group II—53 women without any disorder of the auditory and/or balance system using hormonal contraceptives for at least 2 months, aged 18–40. The patients included in the study underwent a full otoneurological evaluation, detailed laryngological diagnostics and an evaluation of selected parameters of the homeostatic control system—fibrinogen level, D-dimer level, evaluation of APTT and PT indicator, plasma estradiol and progesterone with the Roche Cobas analyser by means of chemiluminescence. The vertigo occurring in the study group was most often central (59.6 % of cases), mixed with compensation in 36.6 % of cases, and peripheral only in 3.8 % of cases, indicating labyrinth damage in 40.4 % of cases. An analysis of the progesterone level, considering the menstrual cycle phase in the group, showed that its value was abnormal in 51.0 % of women in the study group and 47.1 % in the control group. In their own studies, the authors observed that the estradiol level in the plasma, considering the menstrual cycle phase in the study group, was abnormal in 41.2 % of women and that the differences in its concentration were statistically significant in the study and control groups (p = 0.005), which may have a negative impact on the possibility of a thromboembolic episode.