Vol 50, No 1 (2024)

Recovery of consciousness in patients with post-comatose unconscious states after severe traumatic brain injury and the search for their objective markers are among the urgent medical and social problems. To clarify the information content and the degree of consistency of changes in hemodynamic and bioelectrical parameters, in this work we carried out comparative studies of fMRI networks and EEG connectivity at rest in healthy subjects, as well as in patients with post-traumatic disorders of consciousness before and after therapeutic rhythmic transcranial magnetic stimulation (rTMS). It was shown that the characteristics of the functional connectivity of fMRI and EEG at rest are among the informative markers of neuroplasticity during depression of consciousness. A certain topographic correspondence between the fMRI networks and the EEG integral connectivity pattern at rest was established, regardless of the modification of the latter assessment: in the continuous recording mode or pseudo-EP. At the same time, the method of independent fMRI components more clearly reveals the features of the state of individual neural networks, and the indicators of EEG functional connectivity (range 1–15 Hz) are more informative in assessing the integral neural network characteristics and their changes during treatment.

The article describes the results of studies on the impulse activity of various groups of afferent fibers and EMG patterns of lower leg antagonist muscles when walking without, during and after transcutaneous electrical stimulation of the dorsal roots of the lower thoracic spinal cord of a person. Using a mathematical model based on the prediction of the triggering of muscle spindles, variability in the manifestation of impulse activity of various afferents tibialis anterior muscle (TA) and gastrocnemius medialis muscle (GM) when walking under different experimental conditions is shown. It was found that walking on a movable treadmill tape in the absence of spinal cord stimulation was accompanied by strong impulse activity of afferents I (Ia and Ib) and II groups GM, increased excitability of its motorneuron pool and weakening of afferent activity and excitability of TA. On the contrary, electrical stimulation of the spinal cord during walking caused strong impulsive activity of group II TA afferents and moderate — GM, while the activity of Ia fibers TA and GM decreased to moderate impulsivity, Ib afferents of the same muscles had the weakest activity, and the excitability of the GM motorneuron pool was greater than TA. During the postactivation period, walking was accompanied by increased impulses of afferent fibers of group Ib and II GM, weakening of afferent flows of Ib TA and Ia afferents GM, but along with this, afferent signals of group Ia and II to the motorneuron nucleus TA decreased to moderate impulses, and excitability of the motorneuron pool GM was higher than TA. The supposed reflex mechanisms of locomotion regulation are discussed on the basis of well-known phenomena associated with the interaction of various afferent inputs to the spinal cord neuronal apparatus in the system of lower leg antagonist muscles.

Maximum oxygen consumption is an informative indicator of aerobic performance, and its assessment is associated with a significant investment of time. The paper compares the results of maximum tests with a stepwise increasing load with different duration of one load step: 15, 30, 60, 120 and 240 s. Maximum oxygen uptake, total operating time, and pair-wise relationship of protocols were assessed. There was no statistically significant difference in maximum oxygen uptake rate in protocols of different duration. Also, all the studied protocols showed a high correlation with each other (r = 0.92–0.97).

We studied the influence of breathing exercises (BE) with an imposed rhythm on the dynamics of heart rate variability (HRV) parameters in order to study the nature of adaptive processes in the body of girls with different initial levels of total HRV. Heart rate, time indicators: SDNN, mNN, RMSSD, pNN50 - and spectral parameters: TP, HF and HFnu, LF and LFnu, LF/HF - as well as IVR and IN indices were evaluated. According to the level of SDNN, individuals with conditionally low and conditionally high levels of total HRV were identified - groups LV (40 (31; 47) ms) and HV (64 (58; 70) ms). At rest, HRV parameters in HV-girls were significantly higher than in the LV-subgroup. After BE, a significant increase in SDNN and TP was observed in the LV-subgroup, against the background of a decrease in HF and HFnu and an increase in LF and LFnu, and the LF/HF ratio after BE increased by 80%. In HV-girls after BE, an increase of 6% in heart rate was recorded, but not in total HRV parameters: a decrease in HF and HFnu was compensated by an increase in LFnu, as a result, the LF/HF ratio increased significantly by almost 1.5 times compared to the rest level. In LV-girls, the indicators of autonomic balance index (AVR) and stress-index (SI) were higher by 2.6–2.7 than in the HV-subgroup. After BE, a decrease of 24 and 19% in the parameters of AVR and SI was observed in the LV, but not in the HV-subgroup. Thus, the adaptation of the work of the heart to BE occurred in a similar way in LV- and HV-individuals, however, it differed in different adaptive costs of such an effort for LV- and HV-subjects.

The autonomic nervous system is a key link in the course of adaptation and adaptive reactions of the organism to various environmental factors. The aim of this study was to assess the heart rate variability of primary school children during a course of speleoclimatotherapy. The heart rate variability were evaluated in 175 practically healthy children aged 7–10 years. In the course of the study the effect of speleoclimatotherapy on the balance sympathetic and parasympathetic nervoussystem was studied using the parameters of spectral analysis of heart rate variability (HRV). HRV data were analysed in the frequency domain: total wave power (TP), high frequency waves (HF), low frequency waves (LF), very low frequency waves (VLF), vagosympathetic index LF/HF. After a course of speleoclimatotherapy the analysis of the obtained results allowed us to establish statistically significant differences in the groups of boy and girls with vagotonic and normotonic type of regulation. After a course of speleoclimatotherapy reduction of the indexe of a vagosympathetic balance (LF/HF) to normal values was found in the groups of sympathotonic boys and sympathotonic girls, while in sympathotonic girls there was an increase in the value of the total power (TP). It is possible to speak about the restoration of vegetative equilibrium and increase of adaptive capabilities of the child’s organism due to adaptation to the microclimate of speleo-chambers.

The aim of the study is to investigate the dynamics of venous blood glucose, insulin, and C-peptide in response to intake a meal normalized to body mass in obese patients without and with type 2 diabetes mellitus. Venous blood samples were taken from 7 healthy subjects, 9 obese patients, and 10 obese patients with type 2 diabetes mellitus (mean period of diagnosed diabetes 7 years) before and 30, 60, 90, 120, and 180 min after a mixed meal (6 kcal/kg of body mass); additionally, 9 patients with obesity and type 2 diabetes mellitus and 3 healthy volunteers completed a hyperinsulinemic euglycemic clamp test. In patient groups the energy content of food did not differ, but was 1.8 times higher than in the control. An increase in glucose level one hour after a meal was maximal in patients with type 2 diabetes, but an increase in insulin and C-peptide — in obese patients, that related to impairment of insulin-dependent glucose uptake by tissues and of the rate of insulin secretion (dysfunction of â-cells) in patients. At the same time, an increase in the total area under the curve “C-peptide–time” shows that the maximum secretory response of â-cells is comparable in obese patients without and with type 2 diabetes mellitus. The absolute blood glucose level 90 minutes after a meal was closely correlated with the M-index — the marker of systemic sensitivity to insulin (r_s = –0.82, p = 0.002). Our results characterize the features in the regulation of carbohydrate metabolism after intake a mixed meal, normalized to body mass, in people with the varying severity of metabolic disorders, and open up prospects for a wider application of this test in practice.