[Effect of mannitol on blood recirculation in the brain after interruption of the blood flow]. / Vliianie mannitola na retsirkuliatsiiu krovi v mozge posle ostanovki krovotoka.

Premedication with mannitol before circulatory arrest not only promotes the reflow in the brain microvessels but also increases their diameters, thereby making more favourable conditions for blood supply of the brain after circulatory arrest. The data were obtained with the aid of automatic morphometry on microscopic slices of the dog brain perfused with Indian ink.

[Bradykinin, thrombin and prostaglandins as modulators of microthrombogenesis in local injury of the blood vessel wall]. / Bradikinin, trombin i prostaglandiny kak moduliatory protsessa mikrotromboobrazovaniia pri lokal'nom povrezhdenii sosudistoi stenki.

The microthrombogenesis parameters were studied after local laser injury to the rat mesenterial venule in the presence of infusion of bradykinin (20 micrograms/kg/min) and thrombin (10 Units/kg/min). Bradykinin diminished and thrombin, on the contrary, increased the hemostasis parameters, this effect being observed only during the first minutes after the drug infusion. Activation of the blood kallikrein-kinin system preceded the action of thrombin. It is suggested that apart from prostaglandins, the component of the Hageman factor system may play an important role in the control of microhemostasis in the injured vascular wall.

[Mathematical model of transcapillary metabolism in patients with mitral valve insufficiency]. / Matematicheskoe modelirovanie transkapilliarnogo obmena veshchestv u bol'nykh s nedostatochnost'iu mitral'nogo klapana.

Application of a mathematical model of microhemocirculation enabled one to assess quantitatively the magnitude of transcapillary albumin metabolism and total hydraulic resistance of metabolic vessels, as well as the effect of geometric, biophysical and hemodynamic parameters on transport characteristics of the capillaries. Dramatic changes in transcapillary metabolism and in blood rheologic properties are classified with factors that determine the occurrence of postoperative complications in patients with mitral valve failure.

Vasoactive peptides and regulation of hemodynamics in different functional states of the organism.

It is important to emphasize that the biochemical systems participating in humoral hemodynamic regulation may function at any level of the circulatory homeostasis: in the blood as a biological fluid constantly circulating along the vessels, at the microcirculatory bed where the exchange with tissues is realized, on the tonic activity of the resistive and capacitance vessels, defining the systemic blood pressure rate and organ redistribution, or, finally, on the main motive force of the blood, the heart. The interrelations of some molecular factors form the biochemical basis for the interaction of the main humoral systems. These factors are kallikrein for kinins and converting enzyme for the renin-angiotensin system, 9-ketoreductase and phospholipase for kinin and prostaglandin systems, and Hageman factors for coagulation, fibrinolysis, and kininogenesis systems. This main scheme includes "functional" connections, which are defined by a physiological interaction, and those between the central and peripheral nervous systems. We may, evidently, postulate an important biological regularity of a multi-functional participation of the same physiologically active factors in maintaining circulatory homeostasis. On the other hand, we have to emphasize the functional unity and joint correlating actions of different biochemical blood systems.

[Substance P and microcirculation during stress]. / Veshchestvo "P" i sistema mikrotsirkuliatsii pri stresse.

The experiments have been made on rats with the use of animals' immobilization on the back during 1 or 24 h as a stressor. Intravital study of the microcirculation in the rat mesentery has shown that P substance in a concentration of 7 X 10(-8) M aggravated the disturbances caused by the immobilization, while antiserum to P substance with an activity of 150 ng SP/equiv. normalized the microcirculation. The action of P substance and antiserum was similar as regards disturbances of vascular permeability for colloid carbon particles. It is concluded that P substance participates in the mechanisms of microcirculatory and vascular permeability disturbances during stress.

[Role of cAMP in regulating the shape of thrombocytes]. / Rol' tsAMF v reguliatsii formy trombotsitov.

Preincubation of platelet suspension with dbcAMP during 2 minutes inhibited the ADP-induced change in platelet shape. An increase of the cAMP content in the cell induced by papaverine inhibiting phosphodiesterase also blocked the change in the shape caused by ADP and prostaglandin E2 (PGE2). Incubation of platelets in medium with pH 9.0 or addition of PGE2 produced a stable change in the shape of the cells. The action of dbcAMP or papaverine on the changed cells accelerated the recovery of the native shape and the content of membrane-bound calcium.

[Effect of prostaglandins E1 and E2 on thrombocyte form and aggregation]. / Vliianie prostaglandinov E1 i E2 na formu i agregatsiiu trombotsitov.

Preliminary incubation of platelets with prostaglandin E1(PGE1) led to the inhibition of changes in platelet shape caused by ADP. PGE1 also blocked changes in the content of membrane-bound calcium in platelets, which are known to take place under ADP-induced changes in platelet shape. Stable changes in platelet shape were observed on incubation in the medium with pH 9.0. Addition of PGE1 in this case stimulated the normalization of the cell shape. PGE2 alone produced changes in the platelet shape and decreased the content of membrane-bound calcium. Simultaneous addition of PGE2 and ADP prevented the recovery of the native shape of the cells.