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Biomedical subjects

V E Katkov

Publications and source records attributed to V E Katkov.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

[Effect of short-term antiorthostatic hypokinesia on carbohydrate metabolic indices and on the beta-lipoprotein content in human blood].

Before and after 5-day bed rest in the head-down position (at an angle of --4.5 degrees) the healthy male test subjects were exposed to selective catheterization with blood samples withdrawn drom different compartments of the cardiovascular system. The content of glucose insulin lactic acid and beta-lipoproteins was measured. After bed rest the systemic circulation--mixed arterial and venous blood--showed a trend for a decrease of carbohydrate metabolism and an increase of the content of beta-lipoproteins. Transcapillary metabolism in different organs, first of all, in the brain and liver altered significantly. The liver began to release glucose and ceased to utilize lactic acid whereas the brain increased substantially its release of beta-lipoproteins. The data obtained were analyzed using a model of carbohydrate metabolism to control and artifical pancreas.

Bed Rest↗
PubMedDate not supplied

[Central hemodynamics in man during decompression of the lower extremities].

Experiments were performed to study the effect of leg decompression in the head-down position at -15 degrees. The method of chronic catheterization was used, pressure was measured in different areas of the cardiovascular system, blood was withdrawn for biochemical analysis. The effect of leg decompression was compared with that of lower body negative pressure. Decompression produced changes in PAP and CVP that were similar in sign but different in magnitude. The decompression-induced changes in PAP and CVP were primarily determined by the area of exposure. Using previous data, a monograph was constructed to evaluate PAP and CVP variations as a function of the decompression mode and site.

Adult↗
PubMedDate not supplied

[Brain blood circulation and oxygen supply in the healthy human being during measured physical loading in a head-down tilt posture].

Eleven healthy male test subjects performed exercises of 600 kgm/min (98 W) for 20 min in the head-down position (-15 degrees). A day before exercises they were catheterized, with catheters implanted into the internal jugular vein and brachial artery. It was shown that exercises in the head-down position led to an increase in cerebral circulation, a decrease in oxygen utilization and a decrease in jugular pressure. CO2 tension in arterial blood and blood outflowing from the brain remained comparatively stable, while base deficiency and buffer capacity decreased by a similar value.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Effect of short-term antiorthostatic hypokinesia on the pressure in various parts of the healthy human cardiovascular system].

Before and after 5-day head-down tilting (-4.5 degrees) blood pressure was measured in different cardiovascular compartments by the technique of selective catheterization: the upper bulb of the internal jugular vein, superior and inferior venae cavae, hepatic, renal and iliac veins, right atrium and right ventricle, coronary sinus, pulmonary and radial arteries. After exposure the pressure in extrathoracic vessels increased by 1.4 mm Hg on the average: in the internal jugular vein it rose by 1.7 mm Hg whereas in the iliac vein by 1.0 mm Hg. The blood pressure in the intrathoracic vessels of the systemic circulation increased, as a rule, by no more than 0.5--0.8 mm Hg. This elevation was characteristic of diastolic regions of the pressure curve (x- and y-collapse). The pressure in pulmonary vessels--pulmonary artery and left atrium--showed a trend for a decrease of 1.3 mm Hg. The factors that may be responsible for the dissimilar changes of pressure in different cardiovascular compartments under the influence of short-term simulated weightlessness are discussed.

Adult↗
PubMedDate not supplied

[Central circulation in the healthy human being during 7 days of head-down tilt and decompression of different body areas].

The effect of 7-day head-down tilt (-15 degrees) and decompression of various body parts (lower body-LBNP, upper body in the area of the hydrostatically indifferent point-UBNP, and local negative pressure applied to both calves-LNP) on central circulation was investigated on eight healthy test subjects who, for 10 days, had catheters (Swan-Ganz) implanted into the pulmonary and radial arteries. It was shown that, when calculated by square centimeter of the decompression area, the effect of UBNP on central venous pressure (CVP) and pulmonary artery pressure (PAP) was 3-4 times greater than that of LBNP or LNP. This indicates a high sensitivity of this body part to the exposure. During the 7-day study, CVP and PAP showed the most distinct changes. By the 7th hour of the head-down tilt study, CVP remained unchanged and systolic PAP increased by 5.5 mm Hg (27%) (p less than 0.05). This was paralleled by a decrease of plasma aldosterone and renin. By the 2nd day of the study, CVP and PAP were close to the pretest level; on the 3rd day, they began to decline and remained about 3 mm Hg lower than the pretest values to the end of the study (p less than 0.05). During this same period, the contractility of the right heart (the mean rate of right ventricular pressure increment) decreased by 34% (p less than 0.05) and its work by 27% (p less than 0.05). By the 24th hour after the study (the recovery period), CVP and PAP were close to the pretest values, whereas heart rate, cardiac index and oxygen tension in the mixed venous blood were significantly higher than the pretest values (p less than 0.05). The factors responsible for these changes and the potential application of the catheterization technique in biomedical investigations during real space flight are discussed.

Adult↗
PubMedDate not supplied

[Water content of the lungs during 7-day anti-orthostatic hypokinesia].

The time-course variation of the water content of the lungs of seven male volunteers were examined during 7-day head-down tilt (at -15 degrees). As compared to the horizontal subjects, the tilted subjects showed a significant increase in the water content from 557 +/- 19 ml to 612 +/- +/- 63 ml by the 7th hour of the tilt. Later on the parameter gradually declined and on tilt day 7 almost returned to the pretest level, i.e., 567 +/- 46 ml. This increase in the water content during the first hours of the exposure can be attributed to the hydrostatic factors: higher pulmonary artery pressure and higher cardiac output. The increase in the water content on tilt days 3-7 can be associated with changes in the permeability of lung capillaries, drainage function of the lymphatic system of the lungs, and colloidal-osmotic pressure in the perivascular space of the lungs.

Adult↗