Vol 31, No 10 (2024)

BACKGROUND: Chronic radiation exposure due to residence in areas contaminated with radionuclides remains a pressing concern globally, as it increases the risk of leukemia, solid malignancies, and other diseases. According to current understanding, many human pathologies are underpinned by somatic mosaic mutagenesis, particularly involving sex chromosomes. The X chromosome plays a critical role in immune function and autoimmune pathogenesis, and X chromosome aneuploidy is linked to development of various somatic disorders. Prior cytogenetic studies of radiation-exposed populations in the Southern Urals revealed increased X chromosome involvement in micronuclei formation, warranting further investigation into X chromosome aberrations.

AIM: To assess intra- and interchromosomal aberrations involving the X chromosome in peripheral blood T lymphocytes in women with chronic radiation exposure during long-term follow-up.

METHODS: This pilot study included five women exposed to chronic radiation in the Southern Urals (mean age: 74.0 ± 0.8 years; mean cumulative red bone marrow dose: 1.35 ± 0.30 Gy). A comparison group consisted of five women (mean age: 66.3 ± 1.2 years; mean red bone marrow dose: 0.010 ± 0.006 Gy; range: 0–0.03 Gy) who lived under similar socioeconomic conditions and had received less than 70 mGy of total red bone marrow exposure during follow-up. X chromosome aberrations were analyzed using multicolor banding (mBAND). Aberration frequency was calculated per genome equivalent, adjusted for donor age. The frequency of cells with X chromosome aneuploidy was also assessed.

RESULTS: The frequency of X chromosome aberrations was higher in irradiated women compared to the comparison group (0.100 ± 0.036 vs 0.019 ± 0.011; U = 3, p = 0.0476). In irradiated women, a greater variety of aberration types was noted, including a ring chromosome, an isochromosome, and a chromosome presumably formed as a result of chromothripsis. The mean frequencies of X chromosome aneuploidy in irradiated women did not differ significantly from those in the comparison group (p = 0.4); however, interindividual variation may exist.

CONCLUSION: The findings may indicate a more intense mutational process in individuals chronically exposed to radiation. The study of X chromosome aberrations in peripheral blood T lymphocytes of women chronically exposed to radiation in the Southern Urals is promising and should be continued.

BACKGROUND: Residents of the European North, characterized by a sharply continental climate, develop specific physiological mechanisms to adapt to significant seasonal fluctuations in temperature and other meteorological parameters. Assessing individual cardiac responses to these seasonal variations is essential for understanding physiological survival strategies and adaptation mechanisms in extreme climates.

AIM: To determine the relationships between temporal-frequency parameters of cardiac function based on heart rate and TP segment duration in January and May in 15–16-year-old adolescents residing in Syktyvkar.

METHODS: ECG were recorded in 22 adolescents aged 15–16 years in a standing position and in response to a clinostatic test in January and May ECGs were obtained in lead II, and heart rate and TP segment duration were measured based on 20 consecutive cardiac cycles. Statistical analysis was performed using Microsoft Excel.

RESULTS: The analysis of group mean values for heart rate and TP segment duration revealed no statistically significant seasonal differences. A more detailed analysis of individual data demonstrated significant seasonal variability in both heart rate and TP segment duration. In the winter period, heart rate shifts in response to the clinostatic test were more pronounced and reached up to 39%, compared to May (maximum shift of 23%). A similar trend was observed for TP segment duration. An individualized assessment revealed considerable seasonal shifts in both heart rate and TP segment duration among many of the participants.

CONCLUSION: The study confirmed the necessity of an individualized approach to assessing responses to seasonal environmental factors.

BACKGROUND: Geomagnetic field variations are a significant environmental factor influencing human well-being and physiological state, particularly the cardiovascular system. However, both the biophysical mechanisms underlying this influence and its phenomenological patterns across various spatiotemporal scales remain poorly understood. This study continues the investigation of the previously identified effect of synchronization between resting heart rate oscillations and geomagnetic field variations within the millihertz frequency range (periods of 3–40 minutes), referred to as the “biogeosynchronization effect.”

AIM: To evaluate the possible role of the autonomic nervous system as a mediating pathway in the human body’s response to geomagnetic field variations.

METHODS: From 2012 to 2024, a total of 673 experiments involving resting-state electrocardiographic interval recordings were conducted in two groups: eight healthy volunteers (group 1), each undergoing multiple sessions lasting 100–120 minutes, and a cohort of 39 individuals (group 2), each with a single 60-minute session. The frequency of biogeosynchronization effects in minute-by-minute time series of heart rate and heart rate variability parameters was compared. Cross-correlation and wavelet analysis methods were employed.

RESULTS: Across the entire dataset, synchronization between heart rate parameters and components of the geomagnetic field vector occurred in 32% of cases, whereas heart rate variability parameters showed synchronization in only 9%–17%, according to correlation analysis, representing a two-fold or greater difference. Based on wavelet spectrum similarity, heart rate synchronization was observed in 40% of cases and heart rate variability parameters synchronization in 24%–28%. Individual distributions for each subject in group 1 and pooled results for group 2 revealed similar patterns.

CONCLUSION: The biogeosynchronization effect appears significantly more frequently in heart rate changes (p < 0.001) than in heart rate variability parameters, both in repeated individual recordings and in group-level analysis.