Study on the Oxygenation Velocity of the Human Red Cell

Mochizuki, Masaji

doi:10.2170/jjphysiol.16.635

Cited by 33 publications

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“…The diffusivity of 02 across the RBC boundary was expressed in terms of the transfer coefficient (ri(02)), which was determined to be 2.5 x 10-6 cm • s-1 • Torr-1 by using a numerical solution of oxygenation equation (KAGAWA and MOCHIZUKI, 1982) by referring to the experimental data (MOCHIZUKI, 1966). The transfer coefficient of C02 (,(C02)) was also estimated from the numerical solution of the diffusion equation accompanying the HC03 -shift , and from the experimental data on the C02 diffusion and HC03 -shift (NIIZEKI et al, 1983.…”

Section: Computation Of (A-v)co2 and (V-a)ccozmentioning

confidence: 99%

Theoretical analyses for arterial-venous O2 content difference and Haldane effect during rebreathing.

Kagawa

Mochizuki

1987

Jpn.J.Physiol

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The Haldane effect coefficient in vivo and arterial-venous 02 content difference ((a-v)Co2) are, more or less, influenced by the contact time (ta), Po2 and P~o2 differences between venous blood and alveolar air. To increase the accuracy of the (a-v) Cot and the cardiac output measured by means of the rebreathing technique, factors to correct the Haldane effect (F(H)) and (a-v)Co2 (F(avCo2)) were obtained theoretically from the numerical solutions of simultaneous 02 and C02 diffusions in the red blood cell. Both the factors were complicated functions of t~, the difference in P~o2 between venous blood and alveolar air, as well as (a-v)Co2. For simplicity, we eliminated t~ from the above functions by using the standardized relation between the t~ and (a-v)Co2 measured from a rebreathing experiment in man. The F(H) was a linear function of (av)Co2. The (a-v)Co2 was calculated by dividing the product of F(H) and the slope of the C02 dissociation curve by that of a gas exchange ratio against the P~o2 in rebreathing air. The F(avCo2) was given by a ratio of (a-v)Co2 at any alveolar P~o2 to the standard one, in which arterial blood has the same intracellular pH as that in venous blood. It was a linear function of the difference in P~o2 between venous blood and alveolar air, whose slope was inversely related to the (a-v)Co2 itself.Key words : 02 and C02 diffusion in RBC, Haldane effect, arterialvenous 02 difference, R-P02 relation, contact time.MocHizuK! and KAGAWA (1986) clarified that the coupled 02 and C02 diffusions in the red blood cell (RBC) are not so fast, that the C02 equilibrium is hardly established between alveolar air and capillary blood during the contact time (ta).•The venous-arterial C02 content difference due to the Haldane effect ((va)C~o2(H)) has hitherto been expressed by multiplying the slope of the C02 dissociation curve (a') by the difference between the true-and oxygenated-venous Pco2 (oxPv~o2 -trPv~o2) (CHRISTIANSEN et al., 1914). Using this relation,

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Section: Computation Of (A-v)co2 and (V-a)ccozmentioning

confidence: 99%

Theoretical analyses for arterial-venous O2 content difference and Haldane effect during rebreathing.

Kagawa

Mochizuki

1987

Jpn.J.Physiol

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“…In their measurement, the flow velocity of the suspension in the mixing and observation tubes was approximately 4.6 m which is about 3.5 times faster than that used by NIIZEKI et al [23] and about 10 times faster than that of MOCHIZUKI [16]. As a result, in the early stages of the diffusion process, the oxygenation rate was significantly greater than that measured by MOCHIZUKI [16]. However, it was reduced as the reaction proceeded, eventually falling below the latter rate as the BSA concentration was increased.…”

Section: Evaluation Of the K And S Values For 02 Co And Co2mentioning

confidence: 76%

“…UCHIDA et al [31] measured the C02 diffusion rate in a thin layer of hemoglobin solution, and found that the inward and outward diffusions were equally retarded at the gas-liquid interface. NIIZEKI et al [23,24] measured the C02 diffusion rate in the RBC under lowered convective conditions and found that the value of tj for C02, being 2.5 x 10-6 cm • s-1 • Torr-1, was identical to that for 02 [9,10,16].Oxygenation and deoxygenation reactions of hemoglobin are very fast [20] and hydration and dehydration reactions of C02 are also highly accelerated by carbonic anhydrase in RBC [23]. Thus, the rates of 02 and C02 reactions with RBC are limited by the transfer rates of these gases and HC03 -ion across the RBC interface as well as by the intracellular diffusion rate.…”

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confidence: 88%

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confidence: 89%

“…02 and C02 at the RBC membrane, which were both equal to 2.5 x 10-6cm•s-1 •Torr-1 [9,10,16,23,24]. Setting k = 6.58 x 10-3cm•s-' •Atm-1 together with the measured rj value into Eq.…”

Section: Evaluation Of the K And S Values For 02 Co And Co2mentioning

confidence: 99%

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Relationship between the transfer rate and the gap in partial pressure of gas molecules at a heterogeneous interface.

Mochizuki¹

1988

Jpn.J.Physiol

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The partial pressure of a gas corresponds to the kinetic energy per unit volume. At equilibrium, the kinetic energy in the gas phase, or the partial pressure of the gas, must be equal to that in the liquid phase. On the other hand, the number of gas molecules dissolved in a unit volume of solution is usually smaller than the number of molecules in the same volume of gas. Consequently, the kinetic energy of a gas molecule in solution must be higher than that in the gas phase. Thus, in order for the gas molecule to cross a heterogeneous interface, it must undergo a rise of fall in kinetic energy. To counter the change in energy transfer rate across the interface, a gap in partial pressure appears essential.We [18] introduced a term, transfer coefficient, to evaluate the relationship between the magnitude of the gap in partial pressure and the transfer rate across the red blood cell (RBC) membrane. The transfer coefficient (ii) was obtained by dividing the diffusion flux by the size of the gap in partial pressure. Thus, the dimensions are similar to those of permeability. However, , is concerned with the discontinuity in partial pressure at heterogeneous interface caused by the difference in kinetic energy, while permeability is related to the diffusibility within a thin layer such as is found in artificial and some biological membranes. UCHIDA et al. [31] measured the C02 diffusion rate in a thin layer of hemoglobin solution, and found that the inward and outward diffusions were equally retarded at the gas-liquid interface. NIIZEKI et al. [23,24] measured the C02 diffusion rate in the RBC under lowered convective conditions and found that the value of tj for C02, being 2.5 x 10-6 cm • s-1 • Torr-1, was identical to that for 02 [9,10,16].Oxygenation and deoxygenation reactions of hemoglobin are very fast [20] and hydration and dehydration reactions of C02 are also highly accelerated by carbonic anhydrase in RBC [23]. Thus, the rates of 02 and C02 reactions with RBC are limited by the transfer rates of these gases and HC03 -ion across the RBC interface as well as by the intracellular diffusion rate. Therefore, estimation of the i values of the RBC and alveolar membranes is a key problem for the kinetic studies in the

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Diffusion of Gases Across the Alveolar Membrane

Forster

1987

Comprehensive Physiology

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Study on the Oxygenation Velocity of the Human Red Cell

Cited by 33 publications

References 3 publications

Theoretical analyses for arterial-venous O2 content difference and Haldane effect during rebreathing.

Theoretical analyses for arterial-venous O2 content difference and Haldane effect during rebreathing.

Relationship between the transfer rate and the gap in partial pressure of gas molecules at a heterogeneous interface.

Diffusion of Gases Across the Alveolar Membrane

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