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Objective — To compare melatonin levels in saliva during a 24-hr day in order to identify the specificities of circadian melatonin secretion in obese adolescents with or without obstructive sleep apnea (OSA). Material and Methods — We examined 18 obese adolescents with OSA, 12 obese adolescents without OSA, and 15 healthy adolescents with a normal body weight, from whom saliva was sampled four time during the 24-hr day. Polysomnography was used to diagnose OSA. Saliva samples (n=180) were subjected to enzyme-linked immunosorbent assay. Results — Obese adolescents with OSA had higher evening melatonin levels than obese adolescents without OSA. For example, this indicator in OSA patients was 5.3 times higher than in participants without OSA, who had the lowest evening melatonin level among all groups. In both obese groups, nighttime melatonin levels were significantly lower than in the control group. A positive correlation was detected between the levels of morning and afternoon melatonin and body mass index only in obese adolescents without OSA (r=0.58; p=0.03 and r=0.68; p=0.01, respectively). It was found that evening melatonin correlated with minimum blood oxygen saturation (SaO2) in the entire sample of adolescents with OSA (r=-0.69; p=0.008), and it also correlated with time with SaO2 <90% in the group with clinical manifestations of OSA (r=0.76; p=0.003). Nighttime melatonin levels negatively correlated with the minimum SaO2 value solely in the group with clinical manifestations of OSA (r=-0.58; p=0.035). Conclusion — The circadian melatonin secretion in obese adolescents differed, depending on the presence or absence of OSA, and correlated with the level of oxygen desaturation in OSA patients, to a greater extent – in the presence of clinical manifestations.

Using the model of dark stress caused by animal maintenance at dimmed light we showed that Trametin (product obtained during liquid-phase culturing of Trametes pubescens xylotroph fungi) effectively prevented oxidative stress under conditions of light deprivation. The preparation increased the level of unsaturation of lipids, reduced the concentration of primary and end-products of LPO, and increases both the integral parameter of the antioxidant defense system (total antioxidant activity) and its components (activity of superoxide dismutase and reduced glutathione).

The role of glutathione S-transferase for the life of the cell and the entire organism is related to their participation in the processes of detoxification of xenobiotics and antioxidant protection. Genetic variability of glutathione S-transferases appears in the form of different enzymatic activity of the corresponding protein products. In this study, a comparative analysis was conducted on the frequency of genotypes of three genes in the glutathione S-transferases gene superfamily (GSTM1, GSTT1, GSTP1) from representatives of two ethnic groups, Russian and Buryat. To this end, genetic typing of DNA samples was performed by polymerase chain reaction. Statistically significant differences in the frequency of occurrence of allel es A, B, C of the GSTP1 gene (р = 0.026) were found between the groups of teenagers compared. It was found that the frequency of the allele A, which codes for the active variant enzyme, is significantly higher in the Buryat ethnic group (p = 0.012). The allele B, the product of which is a "slow" version of the enzyme, was significantly more common in the Russian ethnic group (p = 0.014). In the GSTM1 and GSTT1 genes, no statistically significant differences in the frequency of occurrence of "zero" and "functional" genotypes between the compared groups of teenagers were found. however, there was a tendency to increase in the frequency of the "zero" genotype of the GSTM1 gene in the Russian ethnic group. In addition, the frequency of the "zero" genotype in two genes GSTM1 and GSTT1 at once was almost two times higher in the Russian ethnic group than in the Buryat ethnic group.Key words: glutathione S-transferase; gene polymorphism; ethnic groups; teenagers.Роль глутатион-S-трансфераз в жизнедеятельности клетки и всего организма связана с их участием в процессах детоксикации ксе-но биотиков и антиоксидантной защите. Генетическая вариабель-ность генов глутатион-S-трансфераз проявляется в различной ферментативной активности соответствующих белковых продук-тов. В работе представлен сравнительный анализ частоты аллелей и генотипов трех генов суперсемейства глутатион-S-трансфераз (GSTM1, GSTT1, GSTP1) у подростков из двух этнических групп -русских и бурят. Для этого было проведено генотипирование об-разцов ДНК методом полимеразной цепной реакции. Показано, что между сравниваемыми группами подростков наблюдаются статистически значимые различия по частоте встречаемости алле-лей A, B, C гена GSTP1 (р = 0.026). Аллель «дикого» типа A, кодиру-ющий «активный» вариант фермента, чаще встречается у коренно-го населения, в этногруппе бурят (p = 0.012). Аллель В, продуктом которого является «медленный» вариант фермента, напротив, чаще отмечается у пришлого населения, в этногруппе русских (р = 0.014). По генам GSTM1 и GSTT1 статистически значимых раз-личий по частоте встречаемости «нулевых» и «функциональных» генотипов между сравниваемыми группами не обнаружено. Тем не менее отмечена тенденция увеличения частоты «нулевого» генотипа гена GSTM1 у пришлого населения; кроме этого, частота «нулевого» генотипа одн...

BackgroundHypercholesterolemia (HCH) takes a significant position in the progression of total cardiovascular risk. Risk prediction of hypercholesterolemia is necessary in the early stages of ontogeny, in childhood, in cardiovascular disease onset. Genetic predisposition plays an important role in this progression.Research goalTo define the role of insertion-deletion polymorphism (Ins/Del) Apolipoprotein B gene in the lipid disorders formation in teenagers with essential hypertension (EH).MethodsIn total 182 Caucasian teenagers (Russia, Irkutsk) aged 12–18 years (15,52±1,25 years: 109 males and 73 females) were included in the study. The first group: 70 teenagers diagnosed with EH with no hypercholesterolemia (EH-HCH). The second group: 39 teenagers EH+HCH. The control group included 73 teenagers with arterial pressure levels<90 percentile of blood pressure distribution curve for the corresponding age, sex and height and with no hypercholesterolemia. Biochemical measurements of blood lipids were conducted for each teenager. Genotyping of polymorphic variants ApoB (Ins/Del) (rs17240441) was carried out by PCR with agarose gel electrophoresis detection.The results of blood lipids analyses comparison in carriers of different ApoB genotypes showed statistically significant differences in total cholesterol (TC) and low density lipoprotein cholesterol (LDL) in the group of teenagers EH-HCH and the group EH+HCH. For teenagers with EH-HCH, with genotype Ins/Ins, total cholesterol level was −3.74 mmol/L, with genotype Ins/Del – 4.40 mmol/L, with genotype Del/Del – 4.48 mmol/L (p=0.0003). The levels of LDL were 1.60 mmol/L, 2.80 mmol/L, 2.84 mmol/L, respectively (p=0.0003). In the group of teenagers EH+HCH the total cholesterol levels were 5.30 mmol/L, 5.40 mmol/L, 6.08 mmol/L, respectively (p=0.0094). LDL levels in EH+HCH were not statistically different. The differences in lipid profiles were not found in the carriers of different genotypes of the control group.ConclusionsTeenagers with EH, who are carriers of Del-allele ApoB gene, are at risk group for early development of hypercholesterolemia and proatherogenic dyslipidemia.