Vol 28, No 10 (2021)

Introduction: Good sleep is an important determinant of health. Poor sleep quality is associated with poor health outcomes. Restrictive measures introduced due to the COVID-19 pandemic in the spring 2020 have led to unprecedented changes in human lives worldwide warranting research on different aspects of the influence of restrictive measures on human health and behavior. Aim: To study associations between the restrictive measures during COVID-19 pandemic and sleep characteristics in Russia. Moreover, we studied factors associated with changes in sleep patterns. Methods: We conducted a national online survey between 26 April 2020 and 6 June 2020 when the tightest measures were in place. Eligible participants included all Russian adults aged 18 years and over. The questionnaire contained 31 items and included mostly close-ended questions. Sleep quality was assessed before the COVID-19 pandemic and in the last 7 days during the study period. The respondents were asked to determine whether they were getting enough sleep, whether they had trouble falling asleep, and whether they woke up earlier than they wanted. Results: In spring 2020, 2 432 individuals from 62 regions of Russia completed web-based questionnaires. Most of them were from the Republic of Tatarstan (n = 804), Irkutsk (n = 474), Sakhalin (n = 225) and Tver regions (n = 152). For most of the respondents, the sleep characteristics analyzed in the study did not change. Negative changes in comparison with the period before the pandemic were noted a fifth of respondents while positive changes were reported by by 12-30 %. A third of respondents (30.3%) reported that the number of days without getting enough sleep decreased , ranging from 13.8 % in Sakhalin Oblast to 56.9 % in Tver Oblast. Adherence to the self-isolation regimen (OR = 2.15, 95 % CI 1.62-2.86), the presence of children (OR = 0.7, 95 % CI 0.59-0.84) and living in rural areas (OR = 1.58, 95 % CI 1.26-1.98) were the main correlates of sleep problems. Conclusion: Most of responders did not report changes in sleep quality. However, substantial regional differences were identified. identification of characteristics associated with negative sleep changes may contribute to development of targeted measures to mitigate the negative impact of the COVID-19 pandemic.

Introduction: The conditions of haptic contamination with stable strontium disrupt the implementation of programmed cell death, forming early health disorders of the child population. Aim: to study the indicators, characterizing cell death, in children with excess haptic contamination of biological media with natural stable strontium. Methods: Research group: children consuming drinking water from underground drinking water sources with excess content of natural stable strontium, comparison group: children consuming drinking water of satisfactory quality in terms of strontium content.The study of indicators characterizing cell death was carried out by flow cytometry; polymorphism of candidate genes by real-time PCR. Results: It was found that in children exposed to strontium, the content of protein-oncosuppressor p53, proapoptotic reception of CD95+- lymphocytes, Annexin V-FITC+PI--lymphocytes with a simultaneous increase in an average of 1.7 times lymphocytic phenotypes of CD95+- lymphocytes and associated with necrotic death of Annexin V-FITC+PI+-lymphocytes are statistically significant (p < 0.001) decreased by an average of 2.5 times. An increased frequency of the heterozygous genotype of the matrix metalloproteinase gene MMP9 Gln279Arg is 2.5 times higher than the results obtained in unexposed children. Conclusion: The results of the studies allowed us to establish that strontium concentrations in the blood in the range from 0.040 to 0.091 mg/dm3 are associated with inhibition of apoptosis and switching to an alternative pathway of cell death-necrosis, which, against the background of polymorphism of candidate genes, creates a risk of autoimmune pathology.

Introduction: Determination of individual reactions of the nervous system during self-regulation under experimental cold conditions has a potential to contribute to better understanding of the "physiological costs" humans "pay" for adaptation to the climatic factors of the Arctic. Aim: To study the dynamics of the spectral power of the electroencephalogram (EEG) during heart rate variability biofeedback (HRV BF) sessions in experimental hypothermia. Methods: Thirty healthy male volunteers (18-20 years old) participated in the experiment. The experimental group consisted of men who performed the HRV BF session (n = 15) and the control group (n = 15). The experiment included five stages: I - rest (+20 °С); II - HRV BF session for the experimental group and rest for the control group; III - whole cooling (-20 °С) for 10 min; IV and V - states after cooling, similar to stages I and II, respectively. EEG were recorded during each stage of the study using a portable electroencephalograph "Neuron-Spectrum-SM" (Neurosoft, Russia). Results: Body temperature significantly decreased on average by 2.2-2.7 °С (p < 0.001) during cooling. An increase in the power of theta- and alpha-activity of the EEG was revealed in the subjects during HRV BF session; the most pronounced changes were observed during stage V. Desynchronization of the EEG alpha-rhythm with the greatest decrease in the right frontal-central regions was observed in subjects of the control group by stage II (p < 0.05), and at the stage of rewarming (stage V), no significant changes in theta- and alpha-activities EEG were revealed. Significant increases in theta-activity EEG during HRV BF after cooling were observed in subjects in the left frontal, central and temporal brain parts (p < 0.05-0.01), which was caused by an increase in the activity of subcortical regulatory mechanisms and an increase in parasympathetic activity during the HRV BF session. An increase in the power of the EEG alpha-activity, reflecting the combined enhanced influence of thalamic and brainstem structures, was revealed over all brain parts, the most significant increases were also noted in the left frontal, central and temporal brain parts (p < 0.05-0.01). Concluzion: HRV BF training stimulates the central structures of autonomic regulation and parasympathetic activity when exposed to cold contributing to better adaptation to the climatic conditions of the Arctic.

Introduction: Diabetes mellitus (DM) and metabolic syndrome (MS) are characterized by development of atherosclerosis and cardiovascular pathology. Vibration disease (VD) affects oxidative metabolism leading to the development of microangiopathies. However, the evidence on the combined effect of VD and DM or MS on oxidative modification of lipids remains limited. Aim: To study oxidative modification of lipoproteins in individuals with vibrationa disease and metabolic disorders. Metods: In total, 59 patients with VD (group I), 73 people with VD combined with MS (group II) and 35 people with VD and type 2 diabetes (group III) took part in the study. We assessed concentrations of total cholesterol, low density lipoproteins (LDL), oxidized low density lipoproteins (oxLDL), antibodies to oxLDL and thiol status. Results: Serum levels of total cholesterol, oxLDL and antibodies to oxLDL in all groups exceeded the reference values. The proportion of people with a high content of oxLDL varied between 61 % to 72 %. Increased levels of antibodies to oxLDL were observed in 63 % - 85 % of patients in all groups. The concentration of LDL cholesterol was the highest in group II: 3,6 (3,2-4,2) mM/l. Concentrations of oxLDL correlated with the levels of total cholesterol and LDL cholesterol. Lower thiol concentrations were found in 57 % of cases in group II). Conclusion: Our results suggest that individuals with VD have hypercholesterinemia, increased oxidative lipid metabolism and increased production of antibodies to oxLDL independently of metabolic disorders Patients with VD and type 2 diabetes may have decrease antioxidant defense.