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Biomedical subjects

V E Katkov

Publications and source records attributed to V E Katkov.

At least 19 recordsLinked to original sources
PubMed1987

Central and coronary circulation of the normal man during orthostatic and lower body negative pressure tests.

The effects of the tilt test (at 60-70 degrees for 20 min) and LBNP test (at -30 and -60 mm Hg for 20 min each) on the basic parameters of central circulation (15 test subjects) and coronary circulation (11 test subjects) were investigated. The study was performed using thermistor-equipped catheters implanted into the pulmonary artery and coronary sinus and Teflon catheters implanted into the brachial artery. In the study, the basic parameters of central circulation (pressure in the right atrium and pulmonary artery, transmural pressure in these compartments, cardiac index, stroke index, etc.) and coronary circulation (blood flow in the coronary sinus, left ventricle oxygen consumption, coronary resistance, etc.) were measured. Correlation between circulation variations and metabolic requirements was assessed (with respect to changes in acid-base equilibrium of blood). The effect of the tilt test and LBNP test on the basic parameters of central and coronary circulation, blood acid-base equilibrium and oxygenation was compared.

Acid-Base Equilibrium↗
PubMed1985

Coronary circulation of the healthy man exposed to tilt tests, LBNP, and head-down tilt.

The effect of tilt (head-up and head-down) tests, LBNP tests, and 7-d head-down tilt (at -15 degrees) on coronary circulation was investigated in healthy male volunteers. Catheters were implanted into the coronary sinus and brachial artery. The Ganz catheter in the coronary sinus was used to measure volume flow in the area (constant thermodilution), pressure, and to withdraw samples of outflowing blood for biochemical analysis (acid-base equilibrium and oxygenation). Transfer from supine to upright body position, lower body negative pressure (-30 mm Hg for 20 min), as well as 15 degrees head-down (by day 5-6) produced similar changes in the basic parameters of coronary circulation-reduction of blood flow and oxygen consumption, decrease of pressure in the coronary sinus, and increase of coronary resistance. Transfer from head-up to head-down position caused opposite changes of the above parameters. The changes in coronary circulation were adequate for myocardial metabolic requirements since the biochemical composition of the outflowing blood remained essentially constant during the gravitational exposures described.

Adult↗
PubMed1983

Central circulation of a normal man during 7-day head-down tilt and decompression of various body parts.

The effect of 7-d 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 d, 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-d 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).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Effects of various countermeasures against the adverse effects of weightlessness on central circulation in the healthy man.

The effect of lower body negative pressure, local negative pressure below the knee joint, and both pneumatic and mechanical occlusion cuffs at the upper third of the femur on central circulation, oxidative metabolism, and acid-base equilibrium of blood was studied on eight healthy male volunteers with doublelumen Swan-Ganz flow-directed thermodilution catheters implanted for 7 d into the pulmonary artery. The counter-measures against the adverse effects of weightlessness were used in two regimens: regimen I at -30, -50, +40 torr and regimen II at -60, -100, and +60 torr. The parameters were recorded in recumbency, during the head up tilt at 70 degrees for 15 min, and then during the head-down tilt at -20 degrees for 60 min. After the first 20 min of anti-orthostasis, the effects of the above countermeasures in the two regimens were investigated. The tile-induced changes in central circulation, those observed during application of the countermeasures, and the effect of different countermeasures were studied on a comparative basis. It was demonstrated that the highly informative method of implantation of catheters into the pulmonary artery can be successfully used in biomedical investigations of normal men.

Acid-Base Equilibrium↗
PubMed1979

Short-term immobilization of healthy men: right ventricular function and metabolism during graded exercise.

Five healthy male volunteers were subjected to graded exercise tests on a bicycle ergometer (600 kpm/min for 8 minutes) with simultaneous catheterization of the right cardiac ventricle and radial artery, first before immobilization and them after five-day bed rest in the head-down posture (the foot bed end was elevated 4.5 degrees). After immobilization, during exercise the stroke index did not increase, the tachycardia was more marked, the indicators of right ventricular contractility increased [+ max dp/dt, mas (dp/dt) /P, --mas dp/dt], the arterial pressure decreased, and the lactic acid level in mixed venous blood rose. Possible causes of haemodynamic and metabolic alterations, occurring in healthy volunteers during graded exercise following short-term hypokinesis, are discussed.

Adult↗
PubMed1979

Central and cerebral hemodynamics and metabolism of the healthy man during head-down tilting.

Experiments on six healthy test volunteers, who underwent simultaneous catheterization of different cardiovascular compartments, were carried out to study the effect of head-down tilting at an angle of -20 degrees on the central and cerebral hemodynamics and metabolism. By the third hour of exposure, the test subjects showed a decrease in the systolic arterial pressure and increases in the systolic pressure of the right ventricle, heart rate, cardiac output, and oxygen intake. They also displayed a trend for an increase in the content of adenosine triphosphate, a decrease in the content of pyruvic acid, and essentially no changes in the concentration of lactic acid and activity of lactate dehydrogenase in the arterial blood and in the blood flowing out from the brain. The oxygen arteriovenous difference for the systemic and cerebral circulation decreased by 24% and 13%, respectively. The above circulatory and metabolic changes seem to reflect processes of adaptation of the human body to functioning under conditions of cephalad fluid shifts.

Acid-Base Equilibrium↗
PubMed1978

[Effect of short-term antiorthostatic hypokinesia on the central and intracardiac hemodynamics and metabolism in a healthy human being].

The right parts of the heart and the radial artery were catheterized in healthy male volunteers before and 5 days after strict bed rest in antiorthostatic position of the body (-4.5 degrees) After immobilization most values of central circulation showed no essential changes; the only exception were indices characterizing the inotropic myocardial condition. A shift in the direction of acidosis of a mixed character was noted in mixed venous blood, the beta-lipoprotein content increased. A decrease in the arteriovenous difference in oxygen was encountered in blood draining from the heart (from the coronary sinus).

Acid-Base Equilibrium↗
PubMedDate not supplied

[Changes in the central and peripheral circulation and in the acid-base equilibrium of the blood in dogs during a passive orthostatic test].

Integral changes in circulation and acid-base equilibrium of blood were studied on urethane-chloralose anesthesized dogs during a 20 min tilt test. Against the background of a relatively stable mean pressure in the aorta, the blood flow in the aorta and carotid artery diminished, pressure in the right atrium decreased and the heart rate increased. The phase of isometric contraction of the left ventricle increased, ejection time, mechanical systole and intrasystolic index decreased whereas the myocardial contractility increased. The blood flow in the liver, spleen and hind limb skin reduced and in hind limb muscles remained unaltered. In the arterial blood metabolic acidosis and hyperventilation developed.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Indices of human blood acid-base equilibrium and enzymatic activity in short-term antiorthostatic hypokinesia].

Before and after a 5 day head-down tilt of 4.5 degrees blood samples were withdrawn from different areas of the cardiovascular system of healthy male volunteers. Blood was sampled by means of selective catheterization. Parameters of acid-base equilibrium and activities of aminotransferases and alkaline phosphatase were measured. After immobilization the most significant changes were observed in the blood outflowing from the brain in which significant metabolic acidosis and increased activity of aspartate aminotransferase occurred. A slight increase in the activity of aspartate aminotransferase was also observed in the blood outflowing from the liver and kidneys. It is concluded that brain is the organ which is subjected to short-term simulated weightlessness in the highest degree.

Acid-Base Equilibrium↗