Gas exchange and blood circulation status in dogs following replacement of acute blood loss by perfluoro compound emulsions

Blood circulation and gas exchange were examined after replacement of blood loss (50 ml/kg bw) in dogs by a preparation containing perfluorocompound (PFC) emulsion (20 v. %) and protein-salt solution (PSS) consisting of isotonic solution of electrolytes and donor's albumin, the final concentration of the latter in the preparation being equal to 5%. Animals with analogous blood loss replaced by PSS alone served as control. Infusion of the preparation under study led to a steady recovery of the main parameters of the hemodynamics disordered as a result of blood loss. Its infusion to experimental animals was followed by a noticeable increase in oxygen blood capacity, provoked a more considerable elevation of pO2 in arterial and venous blood as compared to control. Compensation with PFS emulsion for homeostatic changes that occurred in dogs after blood loss involved a more active oxygen utilization, whereas in controls, a more considerable increase of cardiac output. The study drug is offered as base for a blood substitute-oxygen carrier.     

Role of glucagon in the splanchnic and systemic hemodynamic changes induced by portal-systemic blood shunting

Portal-systemic blood shunting is often accompanied by hyperglucagonemia and hemodynamic changes. To determine this causal relation, splanchnic and systemic hemodynamics (radioactive microspheres) and plasma glucagon levels (radioimmunoassay) were assessed in conditions of total portal-systemic shunting in portacaval-shunted (PCS) rats and in sham-operated (SO) normal rats. To compare these results, another hemodynamic study was undertaken basally and during glucagon infusion in nonoperated normal rats. PCS rats showed a threefold greater plasma glucagon concentration than SO animals (924 +/- 134 vs. 309 +/- 18 pg/ml, p less than 0.01), and they developed a hyperdynamic splanchnic circulation with higher portal venous inflow than SO rats (8.29 +/- 1.1 vs. 5.09 +/- 0.4 ml/min/100 g, p less than 0.05). Infusion of a pharmacological dose of glucagon in normal rats increased portal venous inflow (from 4.92 +/- 0.33 to 6.24 +/- 0.48 ml/min/100 g, p less than 0.05) so as to imply this hormone in the development of the hyperdynamic splanchnic circulation in conditions of portal-systemic shunting. However, the discrepancies in systemic hemodynamics between PCS and glucagon-infused rats may be a result of the different plasma glucagon levels reached in the two groups.     

Structural changes in the lymph node sinuses in acute blood loss]

By means of light and scanning electron microscopy sinuses of the popliteal lymph nodes have been studied in 50 Wistar male rats. After modelling of an acute hemorrhage in the animals (in 15, 120 min and 1 day) volume of the medullary and marginal sinuses increases essentially, while blood stream intensity decreases in peripheral tissues. Amount of fenestrae in the sinusal lining decreases, that is, perhaps, caused by edema of cytoplasm in the lining cells and accompanied with formation of numerous cytoplasmic protrusions into the sinusal lumen. In 3 days the blood stream level in the peripheral tissues restores, structural organization of the littoral cells in the lymphatic sinuses normalizes. The data obtained demonstrate that during the first day after the acute hemorrhage decrease of hematolymphatic exchange intensity in lymph nodes and enhancement of transitory lymph flow in them take place.     

Effect of hyperoxia on the rate of restoration of blood composition after blood loss]

Regeneration of the peripheral red blood was considerably retarded in the anemic rabbits (blood letting of 2% of body weight) after a 5-hour exposure to the hyperoxiconditions (98% of oxygen in the inhaled air, 2 ata).     

The effect of low-intensity laser radiation on blood metabolic indices in the postresuscitation period]

The effect of He-Ne laser radiation (632.8 nm; 0.3 mW/cm parallel to oxygenation on metabolism indices of blood, taken in early postresuscitation period after discontinuation of hemorrhagic shock was studied in vitro. Compared to oxygenation alone, combined therapy resulted in more marked oxygen consumption of the blood, normalization of plasma antioxidant total activity, superoxydismutase erythrocyte catalase activity, the number of double connections in fatty acid chain of general lipids and membrane viscosity were elevated. Regular dependence of lipid peroxidation on a number of metabolic blood parameters is revealed.     

Morphological changes in the small intestine of rats after its temporary exclusion from blood circulation]

The experiments were performed in 56 albino rats (15of them served as a control. The small intestine was excluded from the blood circulation for 45minutes and then pieces of the proximal and distal parts of the intestine were taken forhistological and histochemical study. It was shown that such a term of anemia resulted indeep but reversible changes in the mucous sheath and in the intramural nervous apparatus of thesmall intestine. The state of the organ wall became normal in 15 days after operation.     

ACTH inhibits the development of primary decompensation of the systemic and portal circulation in acute blood loss in rats]

Using the method of contact luminescent biomicroscopy of the liver and intestine coupled with the measurement of systemic blood pressure by micromanometer and ultrasonic registration of blood flow velocity in portal vein and hepatic artery it has been established that in rats with acute decompensatory hemorrhage fragments of ACTH (1-24) and (4-10) improve the state of portal macro- and microcirculation and increase the life span 2-3-fold. ACTH does not influence the dynamics of acute compensatory hemorrhage and the development of the posthemorrhagic microcirculatory disturbances (local microstases, microthromboses, erythrocyte aggregation).     

The correlation of the indices of animal longevity and mortality in stationary populations with a constant rate of mortality

Equations have been derived on the basis of general ratios of the numbers of different age groups of animals that allow to estimate the mortality coefficient in populations with stationary age structure and intensity of mortality that does not depend on age at their continuous and discontinuous replenishing by frequency of occurrence of individuals of the maximal age. The proposed method of estimation of mortality has been tested on models with different numbers of animals and age classes. The equation gives a non-biased estimate of mortality coefficient for populations with discontinuous replenishing with young individuals at very small sample sizes (less than 10 individuals).     

Effect of reinfusions of autologous blood on the systemic and portal circulation in acute blood loss in rats

The experiments on rats using the method of contact luminescent biomicroscopy coupled with the ultrasonic measurement of systemic blood pressure and blood flow velocity in the portal vein and hepatic artery have revealed that portal micro- and macrocirculation reflects the degree of efficacy of acute hemorrhage treatment with autoblood. Autoblood infusion in animals with compensatory type of posthemorrhagic period restored systemic blood pressure and blood flow velocity in the portal vein and hepatic artery, promoting the development of erythrocyte aggregation and local microcirculation disturbances in the central zone of hepatic functional elements.     

Morphologic changes of the pancreas in hemorrhagic shock and the postresuscitation period

The canine pancreas (20) in the terminal period of hemorrhagic shock and postresuscitation period was studied histologically and electronmicroscopically. There were detected ultrastructural signs of the plasmatic membranes of pancreatocytes and membranes of secretory granules with "leakage" of pancreatic ferments in the interstitial tissue. The incretion of pancreatic ferments in the vascular bed is conditioned by the elevation of proteolytic activity of blood serum in hemorrhagic shock and postresuscitation period.     

Role of neuronal nitric oxide synthase in mediating renal hemodynamic changes during pregnancy

Renal plasma flow (RPF) and glomerular filtration rate (GFR) are markedly increased during pregnancy. We recently reported that the renal hemodynamic changes observed during pregnancy in rats are associated with enhanced renal protein expression of neuronal nitric oxide synthase (nNOS). The purpose of this study was to determine the role of nNOS in mediating renal hemodynamic changes observed during pregnancy. To achieve this goal, we examined the effects of the nNOS inhibitor 7-nitroindazole (7-NI) on kidney function in normal conscious, chronically instrumented virgin (n = 6) and pregnant rats (n = 9) at day 16 of gestation. Infusion of 7-NI had no effect on RPF (4.7 +/- 0.7 vs. 4.8 +/- 0.9 ml/min), GFR (2.2 +/- 0.2 vs. 2.5 +/- 0.4 ml/min), or mean arterial pressure (MAP; 127 +/- 7 vs. 129 +/- 10 mmHg) in virgin rats. In contrast, 7-NI infused into pregnant rats decreased RPF (8.9 +/- 1.6 vs. 6.5 +/- 1.4 ml/min) and GFR (4.4 +/- 0.7 vs. 3.3 +/- 0.7 ml/min) while having no effect on MAP (123 +/- 4 vs. 123 +/- 3 mmHg). In summary, inhibition of nNOS in pregnant rats at midgestation results in significant decreases in RPF and GFR. nNOS inhibition in virgin rats had no effect on renal hemodynamics. These data suggest that nNOS may play a role in mediating the renal hemodynamic changes that occur during pregnancy.