A Comparative Anatomical Study of the Swirling Flow Parameters in the Left Ventricular Cavity in Animals of Different Sizes Based on the Concept of Tornado-Like Flows of Viscous Fluids

Biophysics - Abstract—To substantiate a common mechanism for the flow around the flow channel of the heart left ventricle regardless of the species, the orientation of trabeculae in the left...     

The use of smoothed particles approach in realistic mathematical model of intracardiac blood flow: Simulation of a self-organizing tornado-like flow

We performed computer simulation and visualization of blood flow in the left ventricle by the method of smooth particle hydrodynamics (SPH). This visualization qualitatively describes the evolution of twisted stream and graphically demonstrates the direction of velocity field at each moment of time. The geometrical features of the left ventricle are approximated by three-dimensional segmentation of experimental clinical images obtained from multispiral computer tomography (MSCT). The model adequately describes the possible configuration of swirling flow in the left ventricle and is a part of a comprehensive study of swirling flows in different compartments of heart, which comply with a family of the exact solutions of hydrodynamic Navier–Stokes equations for the class of quasipotential¹ swirling flows. Computer visualization shows how simulated by SPH method jet of a model liquid, which is placed in limited space, remains continuity and keeps its clockwise vorticity along the direction of the flow propagation during the whole cycle. Then it turns on approximately 120° by the time of ejection into the aorta. Such structure of the flow provides more effective pumping of blood as a model liquid through the ventricle as compared to a lamellar flow mode.     

The Effect of Mechanical Compatibility and of Thrombogenicity on the Ingrowth of a New Synthetic Vascular Prosthesis (Experimental Study)

Doklady Biochemistry and Biophysics - Common disadvantages of modern synthetic vascular prostheses are thrombogenicity and lack of biomechanical compatibility with the prothesized vessel. To...     

Tyrosine inhibition of anaphylactic shock in guinea pigs

Experimental investigations on guinea-pigs were carried out to study the role of tyrosine in the prevention of anaphylaxis. It should be noted that the intensity of clinical manifestations of anaphylactic shock was reduced in 5 out of 24 L-tyrosine fed guinea-pigs (20.83%), while in 9 animals (37.5%) anaphylactic shock did not develop. 100% death of control animals was registered. The effect of tyrosine was absent only in 10 guinea-pigs. Positive effect of tyrosine was followed by tyrosine-aminotransferase activation with a tendency towards the decrease in tyrosine plasma level and the rise in cortisol blood level. It is suggested that tyrosine increases glucocorticoid secretion of the adrenal cortex: Glucocorticoids in their turn, enhance tyrosine-aminotransferase activity in the animal liver.