Here we performed individual evaluation of the oxidative stress index that serves as an integral criterion for the balance of LPO-antioxidant defense system in women with endocrine pathology (type 1 diabetes mellitus and infertility with hyperprolactinemia). The state of the LPO-antioxidant defense system was estimated from blood levels of LPO substrates with conjugated double bonds, conjugated dienes, ketodienes, conjugated trienes, thiobarbituric acid-reactive substances, retinol, α-tocopherol, reduced and oxidized glutathione, and SOD activity. The use of this oxidative stress index allowed us to diagnose oxidative stress in female patients with endocrine pathology.

A comparative analysis of melatonin circadian rhythms in Caucasian (incoming population) and Asian (indigenous population) menopausal women with/without sleep disorders depending on the genotype of Clock 3111T/C gene polymorphism was realized.The melatonin level in the saliva was determined four times a day (6:00-7:00, 12:00-13:00, 18:00-19:00, 23:00-00:00 h). The Caucasian women-carriers of the TT-genotype with insomnia as compared to control group-had a higher morning melatonin level and a lower night melatonin level. The Asian women with TT-genotype and insomnia had a lower levels of melatonin as compared to control at daytime, evening and night. A significantly higher melatonin level in the early morning hours was detected in the Caucasian women-carriers of the TT-genotype with insomnia as compared to group womencarriers of the minor 3111C-allele. There were no statistically significant differences in the circadian rhythms of melatonin in the Asian women depending on the genotype of the Clock 3111T/C polymorphism. An assumption with respect to the protective role of the minor allele 3111C in the development of insomnia associated with the displacement of melatonin circadian rhythms in the representatives of the incoming population was made.

We studied the state of the LPO-antioxidant defense system in men aged from 46 to 55 years. The main group included patients with obstructive sleep breathing disorders. The state of the antioxidant defense system was assessed by measuring the blood levels of LPO substrates with conjugated double bonds, conjugated dienes, ketodienes and conjugated trienes, MDA, retinol, α-tocopherol, reduced and oxidized glutathione, SOD activity, and the level of total antioxidant activity of blood. Calculation of antioxidant potential helps to identify the processes of "oxidative stress" in the main group, which is a pathogenetic substantiation for including antioxidant drugs in the complex therapy of patients with OSBD.

We studied parameters of lipid peroxidation (LPO) in women with infertility, resident of the Republic of Buryatia. The levels of malonic dialdehyde (MDA) were increased in the examined infertile women from Buryat and Russian populations. Reduced total antioxidant activity, activity of superoxide dismutase (SOD), and α-tocopherol levels were revealed in patients from Buryat population; decreased concentrations of reduced glutathione were recorded in patients from Russian populations.

The study of LPO processes in adolescents of different races with essential hypertension revealed that Mongoloids exhibit oxidative stress by altering the level of the formation of diene conjugates, the primary LPO products. Caucasians increased the levels of both primary and end products of LPO, diene conjugates, and malondialdehyde. The revealed differences can be genetically determined because ethnic differences in the frequency of SOD2 gene Ala16Val polymorphism and its contribution to the biochemical phenotype were reported. The risk factors are Ala allele associated with increased MDA level for adolescent Caucasians and Val allele linked with decreased level of total antioxidant activity for adolescent Mongoloids.