Features of the EEG Pattern of Sleep Spindles and Its Diagnostic Significance in Ontogeny.

Analysis of the microstructure of sleep using extended EEG monitoring can provide deep understanding of the neuronal activity of the brain. Sleep spindles (SS) are one of the main EEG patterns occurring during the non-rapid eye movement sleep. SS reflect the process of synchronization and provide sleep initiation and maintenance by suppressing sensory information. SS are associated with a wide range of brain functions, such as memory and neuroplasticity, general intelligence and cognitive performance, which undergo various changes throughout the life. In this review we discuss the features of the formation and regression of SS in humans during ontogeny on the basis of published data of the last 5-6 years and fundamental results of previous studies at the Scientific Centre for Family Health and Human Reproduction Problems that formed the basis of the modern study of neurophysiological phenomena of the wakefulness and sleep. The search for diagnostic patterns and prognostic markers of the pathology of higher nervous activity remains a priority in fundamental studies and medical practice. Modern methods for studying sleep and its EEG patterns are the next step in understanding the neurophysiological aspects of the sleep-wake cycle. This will open prospects for predicting postnatal maturation, understanding the mechanisms of brain neuroplasticity in the "sleep-wakefulness" continuum, which is one of the tasks of modern somnology and neurophysiology.

[Changes in the telomeres length in patients with obstructive sleep apnea after continuous positive airway pressure therapy: a pilot study]. / Izmenenie otnositel'noi dliny telomer u patsientov s sindromom obstruktivnogo apnoe sna na fone SIPAP-terapii: pilotnoe issledovanie.

OBJECTIVE: To evaluate a relative telomere length in patients with obstructive sleep apnea (OSA) before and after a 6-month course of continuous positive airway pressure (CPAP) therapy. MATERIAL AND METHODS: Seventy-five men participated in the study, including 50 men with OSA (the main group 1) and 25 men without OSA (the control group). The average age in the total group was 53.4±3.6 years. Thirty-five men completed the study (the main group 2). According to the design, night polysomnography (PSG) was performed for all the subjects, blood sampling to assess the length of telomeres was carried out in the morning according to the standard method. The values of the relative telomere length were obtained using the difference between the values of the threshold cycles for telomeric DNA and the reference gene albumin (∆CCt). After clarifying the diagnosis, CPAP was applied for 6 months. RESULTS: Statistically significant indicators of PSG were revealed: a decrease in NREM 3 in patients with OSA compared to controls (89.3±15.8 versus 150±23.4 minutes), an increase in NREM1-2 in OSA (296.2±31.1 and 170.1±24.5, respectively), REM was 84.6±15.4 in the main group and 118.5±19.5 in the control group. CPAP therapy conducted for 6 months (at least 4-5 nights a week, lasting at least 5-6 hours of night sleep) demonstrated a significant improvement in the qualitative and quantitative parameters of sleep. In patients of the main group 1, there is a shortening of the telomere length compared with the control group (p<0.001). With the elimination of hypoxia and improvement of the structure of sleep after CPAP, there was an increase in the telomere lengths in the main group 1 from 0.28 [0.24-0.29] to 0.32 [0.30-0.34] in the main group 2 (p=0.03). The telomers length in the control group was 0.53 [0.50-0.55]. CONCLUSION: Intermittent hypoxia and fragmentation of sleep in OSA leads to shortening of telomeres. CPAP, by eliminating the pathophysiological triggers of OSA, contributes to an increase in telomeres lengths and can slow down the premature aging in OSA.

Serum Serotonin as a Biomarker of the Efficacy of PAP-Therapy in Sleep Apnea Syndrome.

Serum serotonin levels were determined by HPLC in 30 patients with diagnosed obstructive sleep apnea syndrome before and after 3-month course of PAP-therapy and in 14 subjects without obstructive sleep apnea symptoms. It was found that elimination of hypoxic conditions was associated with an increase in serotonin level. The results demonstrate the effectiveness of PAP-therapy during sleep and allow assessing the role of serotonin as a potential biomarker of intermittent hypoxia during sleep.

[Sleep apnea syndrome, pregnancy and fetal condition]. / Sindrom obstruktivnogo apnoe sna, beremennost' i sostoyanie ploda.

OBJECTIVE: To assess fetal cardiac activity with simultaneous polysomnographic (PSG) study of pregnancy with obstructive sleep apnea syndrome (OSAS). MATERIALS AND METHODS: Forty-nine women, aged 18-30 years, 30-34 weeks pregnant, complaining of snoring, with a positive rating in 2 and/or 3 sections of the Berlin Sleep Questionnaire were included in the study. Sixteen pregnant women with the corresponding gestational age, without complaints of snoring, made up the control group. All participants underwent PSG monitoring and fetal cardiotocography (CTG) according to standard techniques. RESULTS: PSG results demonstrate significant changes in sleep patterns in pregnant women with OSAS. There is a significant reduction in SWS 3, REM. High AHI, accompanied by desaturation and the appearance of activation EEG- patterns of cyclic alternations are characterized the sleep of pregnant women with OSAS. Analysis of CTG results shows that the average values of the basal rhythm are statistically higher in women with OSAS than in the control group. Also, the indicators of the amplitude of the oscillations, the frequency of oscillations and the number of movements in 30 minutes are statistically significantly different. Reaction of the fetus to episodes of apnea in the form of active perturbation, changes in heart rate as bradycardia (to 105-110 beats per minute) or tachycardia (to 155-160 beats per minute) compared to basal level (140 beats per minute) are noted. CONCLUSION: OSAS during nocturnal sleep in pregnant women causes the changes in motor activity and cardiac activity of the fetus that indicates fetal hypoxemia.

Free Radical Oxidation of Lipids as an Indicator of the Effectiveness of CPAP Therapy in Apnea Syndrome.

The processes of free radical lipid oxidation were studied in 47 patients with moderate to severe obstructive sleep apnea syndrome before and after 1-month course of CPAP-therapy (continuous positive airway pressure). The control group consisted of 13 people without clinically confirmed apnea. The material for the study was serum, blood plasma, and erythrocyte hemolysate. The levels of LPO products and antioxidant defense were determined spectrophotometrically and spectrofluorometrically. The changes revealed in patients with obstructive sleep apnea syndrome after CPAP therapy indicate a decrease in the intensity of LPO and restoration of the balance in the "LPO-antioxidant defense" system.

Heat Shock Protein HSP70 in Oxidative Stress in Apnea Patients.

We studied the level of heat shock protein HSP70 under conditions of oxidative stress in 47 patients with apnea. The control group included 13 healthy subjects without verified apnea. Blood serum, plasma, and erythrocyte hemolysate were used to determine LPO and anti-oxidant protection components by spectrophotometrical and spectrofluorometrical methods. HSP70 was assayed by ELISA. A direct relationship was established between the intensity of oxidative stress and HSP70 expression in patients with apnea. Quantitative determination of HSP70 can be used as a molecular marker in the early diagnosis and prognosis of the development of various pathological conditions in hypoxia.