[Assessment of influence of breath holding and hyperventilation on human postural stability with spectral analysis of stabilographic signal].

The influence of breath holding and voluntary hyperventilation on the classic stabilometric parameters and the frequency characteristic of stabilographic signal were studied. We measured the stabilometric parameters on the force platform ("Ritm", Russia) on the healthy volunteers (n = 107) during quiet breath, voluntary hyperventilation (20 seconds) and maximal inspiratory breath holding (20 seconds). Respiratory frequency, respiratory amplitude and ventilation were estimated with strain gauge. We found that antero-posterior and medio-lateral sway amplitude and velocity as well as sway surface at breath-holding and at quiet breathing were the same, so breath holding didn't influence the postural stability. However the spectral parameters shifted to the high frequency range due to alteration of the respiratory muscles contractions during breath-holding versus quiet breath. Voluntary hyperventilation caused significant increase of all stabilographic indices that implied an impairment of postural stability, which was due to the increase of respiration frequency and amplitude. We also found that the spectral indices moved toward the high-frequency range with more pronounced degree of this shift versus breath holding. Besides, amplitudes of spectral peaks also increased. Perhaps such change of spectral indices was due to distortion of proprioceptive information because of increased excitability of nerve fibers during hyperventilation. Maximal inspiration breath holding causes strain of the postural control mechanisms that is reflected as elevation of postural sway frequency with no postural stability changes. Hyperventilation leads to the most prominent strain of balance function and decrease of steadiness that is manifested as increase of center of pressure oscillations amplitude and frequency.

[Comparative results of surgical treatment of patients with morbid obesity].

It was performed a comparative analysis of treatment of 62 patients who were operated for morbid obesity. Patients were divided into 3 groups depending on kind of surgery: jejunal-iliac intestinal bypass, restrictive operations and combined operations. The complications in early postoperative period were diagnosed in 16.6% of patients after jejunal-iliac intestinal bypass and in 10% of patients after combined operations. Regardless of the kind of surgery there was rapid reduction of the body mass in the first year of observation with gradual increase of weight by an average of 5% in the subsequent period. The highest rate of weight loss by the second year was revealed after combined operations (up to 73.4%). Thus it was 1.1 times more than after jejunal-iliac intestinal bypass and 1.3 times more than after restrictive operations.

[Cardiovascular resistance to orthostatic stress in athletes after aerobic exercise].

In the paper cardiovascular resistance to orthostatic stress in the athletes in the two-hour recovery period after prolonged aerobic exercise was investigated. The reaction of the cardiac (stroke volume and cardiac output) and peripheral blood volumes in the lower and upper limbs, abdominal and neck regions in response to the tilt-test before and during two hours after exercise (30 min, heart rate = 156 +/- 8 beats/min) was determined by impedance method: It is found that: (1) at baseline distribution of blood flow in favor of the neck-region in response to the tilt-test, in spite of the decrease in cardiac output, was more efficient in athletes, that was due to a large decrease in blood flow to the lower extremities, and increased blood flow in the neck region; (2) after exercise it was established symptoms of potential orthostatic intolerance: postural hypotension and tachycardia, reduced peripheral pulse blood volume, expressed in a standing position, and reduced effectiveness of the distribution of blood flow in the direction of the neck region; (3) the abilityto effectively distribute blood flow in favor of the neck region in athletes after exercise remained elevated, which was due to a large decrease in blood flow in the abdominal region at the beginning, and in the lower limbs at the end of the recovery period.

[Postural stability during static strain before and after submaximal aerobic bycycle test in athletes].

The aim of study was to investigate static balance control in wrestlers (n = 31) and effects of fatigue on postural regulation in two position: bipedal stance and squat position with open eyes prior to and 2 min after bicycle PWC(170) test. A force platform ("Ritm". Russia) was used to determine static balance control. We found a minimum difference in postural control between wrestlers and controls prior to exercise in bipedal stance. In squat position linear and angular (all p < 0.001) sway velocity of centre of pressure were lower in wrestlers and were negatively correlated to PWC(170) index (r = 0.454 and r = 455, p < 0.001 with linear and angular sway velocities respectively) indicating that 20% dispersion of sway velocities in static strain position may be determined to physical working capacity. After PWC(170) test all parameters of sway were increased in both groups both in bipedal stance (p < 0.01) and squat position (p < 0.001) indicating an important role of muscular fatigue in the decrease of postural stability in both groups. Linear velocity after PWC(170) in bipedal stance increased to an equal extent in both groups but the increases of velocities of sway of centre of pressure in squat position were lower in athletes (ANOVA, p = 0.037 for linear and p = 0.008 for angular sway velocities respectively) and were negatively correlated to an extent of recovery of heart rate after PWC(170) indicating some contribution (6.5-14.2% of dispersion of linear and angular sway velocities) of an recovery rate to maintenance of a high level of postural stability in an static strain position in wrestlers during physical fatigue.

[Bioimpedance spectroscopy parameters of suspensions of young and old erythrocytes].

The bioimpedance spectroscopy (BIS) parameters of the suspensions of young and old erythrocytes were studied. The separation of the erythrocytes by age was made by density gradient. The BIS parameters: extracellular (Re) and intracellular (Ri) fluid resistance, characteristic frequency (Fchar), cell membranes capacitance (Cm) and Alpha parameter of concentrate suspensions of young and old erythrocytes were measured on the BIA analyzer ABC-01 "Medass" in the frequency range 5-500 kHz. It was found that Re (300.4 +/- 30.0 Ohm and 261.2 +/- 21.8 Ohm for old and young respectively, p < 0.05), Ri (86.6 +/- 9.1 Ohm and 73.4 +/- 7.3 Ohm for old and young respectively, p < 0.001) and Alpha (0.305 +/- 0.003 and 0.302 +/- 0.001 for old and young respectively, p < 0.05) of the old erythrocytes suspensions were higher, than of the young one, and Fchar (308.3 +/- 42.0 kHz and 347.4 +/- 48.0 kHz for old and young respectively, p <0.05) and Cm (99.3 +/- 10.1 pF and 112.8 +/- 6.3 pF for old and young respectively, p < 0.01) of the old erythrocytes were lower, than of the young one. The found differences between electrical properties of the suspensions of young and old erythrocytes were obviously determined by the alterations of the red blood cells during aging (growth of intracellular hemoglobin concentration, erythrocytes rapprochement because of diminishing of surface negative charge, increase of red blood cell sphericity and cell membrane permeability for ions). Thus the BIS parameters are related to the erythrocyte aging.

[Evaluation of blood hematological and biochemical parameters by bioimpedance spectroscopy].

The purpose of the study was to determine the capability of bioimpedance spectroscopy (BIS) to evaluate the hematological and biochemical parameters of blood. BIS readings were estimated on an ABC-01 Medass hardware-computer complex; blood hematological and biochemical parameters (n = 46) were determined on automated analyzers. The BIS readings were found to be closely correlated with packed cell volume and hemoglobin and red blood cell values, but weakly related to plasma biochemical parameters and white blood cell counts. BIS readings may be used to calculate red blood cell counts taken in units of measurement in hematological practice, by applying the multiple regression equations. Thus, the blood BIS technique may be employed to estimate basic hematological parameters (hemoglobin concentration, red blood cell counts, and packed cell volume).

[The state of central hemodynamics and variability of hearty rate in sportsmen with various direction of training process].

The state of the central hemodynamic and variability of heart rate (VHR) in high quality sportsmen with various direction of training processes in conditions of relative tranquility was investigated. Was discovered that in sportsmen during the endurance training (group "Endurance", n = 27) and in strength training (group "Strength", n = 17) was noted the decrease in total peripheral blood resistance (TPBR: -15%, p = 0.003 and -16%, p = 0.011 for groups "Endurance" and "Strength" accordingly). However, in group "Strength" the minute blood volume (MBV) was increased (p = 0.012), and temporal and spectral data ofVHR (RMSSD, PNN50, HF)--decreased (p < 0.05) in comparison with control group (n = 56). Part of this differences had to do with increase body mass index (p = 0.005) in the group "Strength". In "Endurance" group the VHR were increased (RMSSD, pNN50, HF, VLF, TP all p < 0.02), the mean arterial pressure was decreased (p < 0.003) without considerable differences in MVB in comparison with the control group. The received data allows to conclude, that in the state of tranquility, the hemodynamic maintenance of the organism of the sportsmen of the "Strength" group takes place on a higher level of MBV and the mechanisms of heart regulation tension. On the other hand, in sportsmen training in endurance, the low level of MBV is taken care of by less tension of the regulation mechanisms of the heart action (higher tonus of vagus).

[Problems in the measurement of human body temperature].

The problems arising in the measurement of human body temperature are discussed. The results of the experimental research are described. The effect of the initial sensor temperature on the results of measurement is explained. It is shown that the thermal or cold irritation of skin when brought in contact with the sensor also has an effect on the measurement results. Recommendations for optimizing the temperature sensor size are given.

[Lipid profile and the deformability of the erythrocytes in athletes]. / Lipidnyi profil' i deformiruemost' éritrotsitov u sportsmenov.

Correlations between rheological properties of blood (viscosity, spheric index, erythrocyte surface area/erythrocyte volume) and lipid profile (total cholesterol, HDLP, LDLP, VLDLP cholesterol, triglycerides, beta-LP) were studied in 24 athletes aged 19-29 years. It is shown that athletes with a low atherogenic index (AI < 2.15) had lower viscosity of blood with standard hematocrit 45% and higher erythrocyte deformability compared to those in athletes with AI > 2.15. The correlation analysis detected positive correlation of erythrocyte suspension viscosity with AI, serum concentrations of triglycerides, beta-LP and negative correlation with concentrations of HDLP cholesterol. The value of the geometric factor of deformability correlated with concentration of VLDLP cholesterol and beta-LP. It is suggested that a close correlation exists between serum lipids and erythrocyte deformability.