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Nitric oxide effect on the hemoglobin-oxygen affinity

100%

Stepuro T. L. , Zinchuk V. V.

nr 1

The biological roles of nitric oxide (NO)-hemoglobin (Hb) derivatives are obscure. It is proposed that NO can function as an allosteric regulator of hemoglobin oxygen-binding properties. We aimed to estimate the effects of NO donors and NO-synthase substrate (L-arginine) on hemoglobin-oxygen affinity (HOA) in experiments in vitro with the various ratios between NO formed and Hb and various oxygen pressures. HOA index (p50), blood pH, plasma and red blood cell (RBC) concentrations of nitrite/nitrate and methemoglobin amounts were measured after the experiments. In our experiments, blood incubation with NO donors (glyceryltrinitrate, molsidomine, sodium nitroprusside, S-nitrosocysteine) or NO-synthase substrate (L-arginine) did not change HOA even at NO:Hb ratio of 1:1. At the same time our results showed that oxygenated blood incubation with S-nitrosocysteine induced an oxyhemoglobin dissociation curve shift leftwards. This indicates a leading role of met-Hb in a modification of Hb oxygen-binding properties. However other NO-modified forms of hemoglobin (S-nitroso- and nitrosylhemoglobin) also may be involved in the regulation of HOA. The results obtained indicate that nitric oxide can be the allosteric effector of hemoglobin, increasing or decreasing its oxygen affinity - possibly, through the generation of different NO-Hb derivatives.

Modeling of the influence of elevated temperature on oxygen distribution in soft tissue

63%

Jasiński M. , Zadoń M.

Engineering Transactions

2023

tom Vol. 71, iss. 3

287--306

The purpose of the study was to analyze the combined model of bioheat transfer and oxygen distribution in tissue during exposition to the external heat impulse. The effect of temperature and thermal damage to the tissue on the values of its thermophysical parameters was taken into account. The variable value of the perfusion coefficient affects the blood velocity in the capillary and thus the distribution of the partial oxygen pressure in the tissue. Various models of the oxygen dissociation curves were also considered and a sensitivity analysis was performed for the parameters of the oxygen distribution model. In the numerical realization stage, the finite difference method and the shooting method were used.

Numerical analysis of the temperature impact to the oxygen distribution in the biological tissue

63%

Jasiński M.

Journal of Applied Mathematics and Computational Mechanics

2020

tom Vol. 19, nr 3

17--28

The aim of the study was to analyze changes in tissue oxygen distribution resulting from temperature changes by the use of the Krogh cylinder model with Michaelis-Menten kinetics. A Hill model was also used to describe the oxyhemoglobin dissociation curve. In particular, variable values of parameters of dissociation curve and blood velocity in capillary were considered. Mathematical description was based on two separate equations for radial and axial directions. An additional task related to determination of the temperature, tissue thermal damage and perfusion was also solved. At the stage of numerical realization, the finite difference method was used.

Analysis of the relationship between hemoglobin-oxygen affinity and lipid peroxidation during fever

63%

Borisiuk M. V. , Zinchuk V. V.

nr 1

Endogenous hyperthermia was induced in rabbits by i.v. pyrogenal administration. Hemoglobin-oxygen affinity and parameters of free radical lipid oxidation in plasma and red blood cells were measured. The content of diene conjugates, malonic dialdehyde and Schiff bases were determined at a pyrogenal dose of 4 minimal pyrogenic doses/kg, and iron-initiated chemiluminescence, catalase activity and a-tocopherol concentration were determined at 6 minimal pyrogenic doses/kg. A rightward shift of the real oxyhemoglobin dissociation curve and activation of lipid peroxidation were observed. Relationships between the parameters measured were analyzed. Decreased hemoglobin-oxygen affinity is considered to be a possible mechanism of activation of free radicals during fever.