[Time perspective, sleep and wellbeing of the elderly during COVID-19 pandemic.]

The purpose of this study was to analyze the association between the time perspective and the psychophysiological state of the elderly during the pandemic COVID-19. 433 residents from 11 Russian cities aged 60,8±9,8 years (range - 50-94 years, women - 78,7%) took part in the study. During the online survey, each participant of the study provided personal data (place of residence, sex, age, height, and weight) and completed the Zimbardo Time Perspective Inventory, the Munich Chronotype Questionnaire, the Beck Depression Inventory and the Yale Food Addiction Scale. It was found that elderly people with a balanced time perspective had the lowest level of depression during the pandemic COVID-19 and less expressed sleep inertia at work days, while those with a past negative time perspective had the highest level of depression, high frequency of detection of food addiction and low sleep efficiency. The other types of time perspective (past positive, present hedonistic, present fatalistic and future) had intermediate values of indicators between these two extreme options. Thus, the conducted studies have shown that elderly people with a balanced time perspective showed the highest level of resistance to psychoemotional stress caused by the pandemic COVID-19.

Association of chronotype and social jetlag with human non-verbal intelligence.

The aim of this study was to evaluate the effects of chronotype and social jetlag (SJL) on intelligence. Subjects were aged 14-25 years (n = 1008). A significant effect of intelligence on academic performance, as measured by the Raven's Standard Progressive Matrices test, was found (F2,917 = 11.75, P < 0.0001, η2 = 0.03). When SJL was less than 2 hours, the intelligence of people with late chronotype was found to be higher than that of subjects with early and intermediate chronotypes (F2,305 = 3.12, P < 0.05, η2 = 0.02). A negative effect of SJL on the results of intelligence testing was noted only in subjects with late chronotype (F2,536 = 2.61, P < 0.05, η2 = 0.02). Our data suggest that people with late chronotype have a higher level of intelligence, but these advantages disappear when SJL ≥2 hours.

Impact of perinatal photoperiod on the chronotype of 11- to 18-year-olds in northern European Russia.

The study investigates the effect of the month of birth and ambient light conditions at birth on sleep length and chronotype among residents of high latitudes. The authors surveyed 1172 persons (609 girls, 563 boys) age 11 to 18 yrs living in five villages and four towns located between 59.5°N and 67.6°N latitude. Survey participation was voluntary and anonymous. Sleep length and chronotype were assessed using the Munich chronotype questionnaire (MCTQ). The study showed the sleep length and chronotype of the children and adolescents depended on sex, age, type of settlement (town/village), and latitude of residence. Latitude exerted a stronger impact on sleep length and chronotype of children and adolescents living in villages than on those of their urban counterparts. Month of birth had no effect on sleep length and chronotype. There was a significant effect of the time of sunrise, sunset, and day length at birth on the chronotype of children and adolescents. A later chronotype was observed in the sample of young persons living above the Arctic Circle who were born during the polar day and polar night.

[Cancer risk in women: a possible connection with geographic and certain economic and social factors].

The paper deals with mulivariate regression analysis of effects of latitude, economic environment and electricity consumption on breast cancer morbidity in 35 countries (1985-2007). Our data are compared with the influence of the same factors on incidence rates for ovarian carcinoma, endometrial and cervical cancer as well as those of the stomach, liver, colon and lung. It was found that rates of morbidity for breast, endometrial, colonic and lung cancer tend to increase north of the equator while cervical, gastric and hepatic cancer incidence is relatively higher in circumequatorial populations. In 1985, geographic factors made a dramatic contribution to hormone-dependent tumors incidence while economic ones--to that of gastrointestinal neoplasms. In the 2000-ies, climate-related risks of hormone-dependent tumors have gradually slumped down while those of economic and social factors have increased.

[Chronotype of human in the north].

Long term acting climatic and social factors of the North causes desynchronization of human circadian system that can lead to increase in risk of age-associated diseases. Earlier on small sample we have shown, that the higher latitude of residing in the North, the higher rate of occurrence of late chronotype. It is noted also, that parameters of daily rhythm at late chronotype person are less expressed, than at early one. The purpose of present research is to study distribution of rates of various chronotypes depending on latitude of residing. Chronotypes were assessed by the Munich Chronotype Questionnaire (MCTQ). Our study includes 772 inhabitants of Komi Republic. It was shown that there is a significant shift to prevalence of late chronotype among inhabitants of the North. Thus, increase in rate of persons with late chronotype, circadian system of which is most sensitive to negative action climatic and social factors of the North, can be one of the causes of its desynchronization and increasing in risk of age-associated diseases at northerners.

[The effects of ultraviolet irradiation upon structure and antioxidant activity of silenan from bladder campion callus].

Effects of UV-B (280-315 nm) and UV-C (254 nm) at various doses upon callus of bladder campion (Silene vulgaris (M.) G. were studied. It was revealed that UV irradiation results in the decrease in arabinose and galactose residues in the silenan--the pectin fraction isolated from callus. The silenan possesses antioxidant activity (AOA) as assessed by the reaction with a stable radical. At the irradiation of callus by UV, the AOA of the silenan and the relative content of phenolic compounds in it increased; the highest increase was observed after the irradiation of callus by UV-B. Positive correlation between the AOA of the pectin fraction and an increase in phenolic compounds was revealed. This evidences that the AOA of the silenan relates to and is partially determined by phenolic compounds in its composition. The UV irradiation may be used as a tool to modify the structural features of the cell walls' polysaccharides in order to produce physiologically-active polysaccharides with desired properties.

[8-hour rhythm of ovarian progesterone secretion in ewe].

Pulse character of hormones secretion in the hypothalamus-pituitary-gonads system is a necessary condition of physiological regulation of reproduction. At the same time, the rhythms of ovarian hormones secretion have not been adequately explored. The researches study mainly three sexually mature ewes. The stages of oestrus cycle were determined on behavioral reactions of females in the presence of ram. Blood samples from jugular vein were collected hourly over 24-hour period during follicular (15-16 days), early (3-4 days) and middle (7-9 days) luteal phase of oestrus cycle, pregnancy (40-105 days) and lactation (30-45 days). 27 experiments were performed. Plasma progesterone was determined by enzyme-immunoassay method. There was no diurnal rhythm of ovarian progesterone secretion in ewes. During early and middle luteal phase of oestrus cycle and lactation, an 8-hour rhythm of progesterone secretion was detected. Follicular phase of oestrus cycle and pregnancy were characterized by irregular rises of fluctuations of progesterone level. It seems that the 8-hour rhythm of progesterone secretion during luteal phase and lactation is controlled by action of intraovarian generator of ultradian rhythms.

[Influence of light and electromagnetic radiation of Sun on circadian rhythms of the total antioxidant capacity of human saliva in the North].

The literature and results of own researches concerning the influence of climatic conditions of the North on human organism are analyzed in the paper. Experimental and clinical data are in accordance with a hypothesis of "circadian destruction" covering the mechanism of negative influence of factors of the North on human health. The model to describe the possible mechanism of action of electromagnetic radiations on circadian system of an organism is offered.

[Food lignins as natural geroprotectors].

Antioxidant properties of different botanic origin water soluble lignins are considered. Possibility to develop onco- and geroprotectors on the base of natural lignins is shown.

[Effect of Earth magnetic field on circadian rhythm of total antioxidant capacity of human saliva in the North].

In the inhabitants of the North during increase of geomagnetic activity and during magnetic calm the decrease of amplitude of circadian rhythm of total antioxidant capacity of saliva is observed. The most favorable conditions to display the circadian rhythm are observed at Kp from 0,5 up to 2. The long residing in the North is connected to influence of irregularly varying geomagnetic activity causing disturbance of function of circadian and antioxidant systems that, probably, is one of the reasons of acceleration of process of aging at northerner and of higher risk of occurrence in them the age associated diseases.

[Effect of natural light during "white nights" and melatonin on circadian rhythm of total antioxidant capacity of human saliva].

The results of our previous experiments indicate that total antioxidant capacity (TAC) of human saliva has a distinct circadian rhythm with maximum in the night and minimum in the daytime. The decrease of amplitude and other parameters of circadian rhythm of TAC of saliva in summer is marked. The aim of the present study was to evaluate an effect of light at night and exogenous melatonin (MT) on this parameter. There were 6 participants in experiments, at which 28 circadian rhythms have been analysed. The method of coulometric titration was used for measuring TAC of saliva. Light at night significantly decreases amplitude (P<0.001) and exogenous MT increases the level of AUC (P<0.05) and mesor (P<0.05). MT in vitro has a highest antioxidant activity among water soluble antioxidants tested (MT, quercetin, ascorbat, mitophen, white lignin, rutin). Pharmacological quantities of MT (0.1%) increases TAC of saliva in vitro as high as three times. The results of calculations indicate that specific TAC of MT is not enough to explain increase in TAC of saliva in vivo conditions. Consequently, MT stimulates biosynthesis and/or redistribution of low-molecular weight antioxidants in the human organism.

[Dynamics of rumenoenteral transport of progesterone in sheep in chronic experiment].

In chronic experiments on pregnant and lactating sheeps with large fistula of rumen the dynamics of progesterone transport in a cavity of temporarily isolated reticulo-rumen depending on a physiological condition of animals, composition of solution filling a cavity of organ, and time of incubation, were studied. On three animals, 24 experiments were carried out. It was established that, during pregnancy, in a cavity of reticulo-rumen more progesterone was transported than during lactation (p < 0.05). Addition of lignin and cellulose to the salt solution increased the progesterone transport in the cavity of reticulo-rumen (p < 0.001). During three-hour incubation of salt solution in the cavity of reticulo-rumen, an increase of progesterone transport was observed in cavity of the organ (p < 0.001). The data obtained confirm the assumption that forestomach of ruminants participates in removing of progesterone from internal environment to enteral one and that carbohydrate polymers facilitate this process.

[Antioxidant status of ewe's blood during pregnancy and lactation].

Antioxidant status of ewe's blood during pregnancy and lactation was studied. It is revealed that the lipid peroxidation in erythrocytes is decreased, whereas in blood plasma is increased in the middle pregnancy, reaching the maximum shortly before peak of progesterone production. The activities of antioxidant enzymes are increased at the end of pregnancy, when the level of progesterone in blood is maximal. The positive correlation between plasma progesterone level and activity of erythrocyte superoxide dismutase (p < 0.01), between plasma cortisol concentration and total antioxidant capacity of blood plasma (p < 0.05) are revealed. It is shown, that the activities of antioxidant enzymes reach a maximum in the critical periods of pregnancy, providing the protection of the maternal organism and the fetus against negative influence of free radicals. The positive correlation between a level of hormones and separate parameters of antioxidant system in blood allows to assume, that progesterone participates in the regulation of enzymatic part of the antioxidant system, while cortisol is implicated in the regulation of the non-enzymatic component of this system in ewes.