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Biomedical subjects

S Nichkov

Publications and source records attributed to S Nichkov.

6 recordsLinked to original sources
PubMed1987

[Effect of the thoracic pumping function on venous return in chronic experiments].

In cats with implanted ultrasonic transducers, interrelationships between phasic oscillations of the blood flow in posterior v. cava due to the chest sucking function and changes of intrapleural pressure, were studied. Linear dependence of shifts of these parameters was only observed in an increased pressure and respective drop in venous blood flow. The dependence was absent in drop of the pressure and increase of venous blood flow. The ratio of the intrapleural pressure shift to magnitude of phasic changes of the blood flow in the posterior v. cava (the pumping coefficient) is suggested for estimation of effect of the chest sucking function upon the venous outflow and for relative estimation of rigidity of the vascular bed's venous portion.

Animals↗
PubMed1981

[Blood flow in the inferior vena cava measured by a Doppler ultrasound flowmeter in chronic experiments on cats].

Supercound Doppler's transducers indwelled in the cat v. cava posterior revealed that the higher blood flow values in chronic experiments as compared to acute ones were due to the effect of the chest suction action on the blood flow. The phasic changes of the venous blood flow occurring at resting and under various effects were related to respiration and heart activity, the respiratory component being more obvious than the cardiac one. A significant correlation existed between the mean value of the blood flow in the v. cava posterior and the respiratory changes of the blood flow amplitude.

Animals↗
PubMed1979

[Hemodynamic structure of pressor reactions to vasoactive substances].

In cats, similar changes of the blood pressure had different hemodynamic structures under the influence of catecholamines or angiotensin. Adrenalin was able to evoke a pressor response by means to either caridac or vascular factor. In the former case, the increase in the cardiac output was induced both by an increasing blood flow towards the heart and by an additive outflow of the blood from the minor to the major circulation; in the latter case, the increase in the general peripheral resistance entailed a decrease in the cardiac output in spite of the augmentation of the venous return which determined a delay of the blood in the minor circulation. The latter variant of interrelationships among hemodynamic parameters can occur under the influence of noradrenaline as well. A combined similarly rendered participation of the cardiac and the vascular factors in the increasing the blood pressure occurs under the influence of angiotensin and sometimes of noradrenaline. The participation of cardiac output in the pressor response may depend on hemodynamic shifts in the minor circulation which either limit or facilitate, or leave unchanged the rate of increment of the cardiac output.

Angiotensin II↗