Synergism in the kinetic reactions of O<sub>2</sub> and CO<sub>2</sub> with human red blood cells*

Nakamura, Toshio; Staub, Norman C.

doi:10.1113/jphysiol.1964.sp007449

Cited by 12 publications

(4 citation statements)

References 23 publications

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“…Presumably in the absence of this enzyme externally, C02 is produced inside the cells more rapidly than it can be hydrated by the buffer system externally, and the external and internal PCO2 become nearly equal, only falling slowly as the uncatalysed reaction proceeds externally. Nakamura & Staub (1964) also determined the rate of the Bohr on-shift without external carbonic anhydrase and obtained a value of 0-2 sec, considerably less than our finding. However, the pertinent conditions may not be comparable; the initial [HbO2] in our work was much higher.…”

Section: Bohr On-shift In Cellscontrasting

confidence: 77%

“…If this method of calculating the exponential rate constant for the over-all process is used, the value of kc is at least as great, if not greater, than the value for the combined reaction. This is also brought out by a comparison of the half-times: those for the deoxygenation reaction in general (Table 1, Nakamura & Staub, 1964) appear faster than the combined reaction process. We do not believe that they were justified in comparing the rates of the combined reaction with those of the Bohr shift alone, because the latter were Bohr on-reactions while the deoxygenation and combined reactions were Bohr off-reactions.…”

Section: Bohr On-shift In Cellsmentioning

confidence: 96%

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Rate limiting processes in the bohr shift in human red cells

Forster¹,

Steen²

1968

The Journal of Physiology

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SUMMARY1. The rates of the Bohr shift of human red cells and some of its constituent reactions have been studied with a modified HartridgeRoughton rapid reaction apparatus using an oxygen electrode to measure the progress of the reaction.2. with an activation energy of 8000 cal.4. The pronounced importance of the C02-bicarbonate system for rapid intracellular pH changes-is discussed in connexion with some physiological situations. 542

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Section: Bohr On-shift In Cellscontrasting

confidence: 77%

Section: Bohr On-shift In Cellsmentioning

confidence: 96%

Rate limiting processes in the bohr shift in human red cells

Forster¹,

Steen²

1968

The Journal of Physiology

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“…The halftime value decreased as the Sot value increased. STAUB (1964) andSTEEN (1968) measured the Bohr-off-shift to have an initial Sot value of 0.85 and 0.93, respectively. They obtained an average half-time value of 0.152 and 0.12s, respectively, which was compatible with the computed data shown by the solid line.…”

Section: Programming Of Diffusion Equationsmentioning

confidence: 99%

Numerical solution of partial differential equations describing the simultaneous O2 and CO2 diffusions in the red blood cell.

Mochizuki

Kagawa

1986

Jpn.J.Physiol

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To describe the overall gas exchange rates in red blood cells (RBC), a computer program for solving the diffusion equations for 02, C02, and HC03 -that accompany the chemical reactions of Bohr-and Haldane-effects was developed. Three diffusion equations were solved alternatively and repeatedly in an increment time of 2 ms. After solving the diffusion equations the Poz, 02 saturation (S02), P02, pH, and HCO3 content were corrected by using the Henderson-Hasselbalch equation, where the buffer value was newly derived from the C02 dissociation curve. In computing the Haldane effect, the buffer value was taken to be 44 mmol l(RBC) -1 pH~ -1, so that the change in intracellular dissolved C02 caused by the Soz change was fully compensated by the subsequent C02 diffusion. The oxygenation and deoxygenation rate factors of hemoglobin were assumed to be 2.09(1 • -S)2'02 and 0.3 s -• Torr 1, respectively. The Poz change due to the Bohr-shift was computed from Hill's equation, in which the K value was given by a function of the intracellular pH. When the parameter values thus far measured were used, the computed Bohr-and Haldane-effects coincided well with the experimental data, supporting the validity of the equations. The overall gas exchange profiles calculated in the pulmonary capillary model showed that the C02 equilibration time was significantly longer than the oxygenation time.Key words ; diffusion in red blood cell, Bohr effect, Haldane effect, overall gas exchange rate.Under physiological conditions in the pulmonary and peripheral capillaries, the 02 and C02 diffusions into and out of the red blood cells (RBC) are mutually influenced by the Bohr-and Haldane-effects. To estimate the overall gas exchange rate, the oxygenation and deoxygenation rates as well as the C02 and HC03 -diffusion rates in the RBC must be solved simultaneously. However, because of

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“…Nach der Umlagerungstheorie von Niesei [58] werden dem Hä-moglobin zwei Molekularzustände mit veränder-lichem Gleichgewicht Hb' und Hb" zugeordnet, während Radford [64] eine statistische Hypothese angibt. Trotz intensiver Bemühungen seit den ersten Untersuchungen von von Hartridge und Roughton (1923) [34,35] über die Kinetik der Hä-m'oglobin-Sauerstoff-Bindung liegen bisher für menschliches Blut unter physiologischen Bedingungen nur sehr lückenhafte, über die vier Geschwindigkeitskonstanten der Adairschen Hypothese keine Ergebnisse vor (Übersicht [68,69] [48,49,56]. Während die Geschwindigkeitskonstante für die Oxygenierung in einem pH-Bereich zwischen 7 und 8 geringfügig pH-und nicht temperaturabhängig ist, wird die Rückreak-tion stark von pH und Temperatur beeinflußt [46,47].…”

Section: Anatomie Der Lungeunclassified

Zur Berechnung der physikalisch-chemischen Austauschvorgänge in der menschlichen und künstlichen Lunge - The calculation of the physical-chemical transfer processes in human and artificial lungs

Kottke¹,

Schmidt²

1976

Biomedizinische Technik/Biomedical Engineering

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Voraussetzungen einer guten Gestaltung und Betriebsweise künstlicher Oxygenatoren und Herz-Lungen-Maschinen sind exakte Kenntnisse der Stoffaustauschvorgänge in der menschlichen Lunge. Es werden die physiologisch-anatomischen Möglichkeiten einer modellmäßigen, geometrischen Erfassung des biologischen Lungenreaktors beschrieben, sowie der Stand der Kenntnisse hinsichtlich der speziellen physikalischchemischen Grundvorgänge (Diffusion, Absorption und chemische Reaktion) behandelt. Abschließend wird geklärt, inwieweit der Stoffaustausch in verschiedenen künstlichen und in der menschlichen Lunge derzeit einer mathematischen und modellhaften Beschreibung zugänglich ist.For a functional design and reliable Operation of oxygenators and heart-lung-machines the exact knowledge of the mass transfer phenomena in the human lung is highly important. Physiological and anatomical possibilities of a geometrical model of the biological lung function are described. The present level of knowledge of the special physical and chemical processes of diffusion, absorption and chemical reactions is presented. Finally, the question äs to whether and to what extent mass transfer in various artificial lungs and also in human lungs, can be examined on the basis of a mathematical model. Einleitung

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Synergism in the kinetic reactions of O₂ and CO₂ with human red blood cells*

Cited by 12 publications

References 23 publications

Rate limiting processes in the bohr shift in human red cells

Rate limiting processes in the bohr shift in human red cells

Numerical solution of partial differential equations describing the simultaneous O2 and CO2 diffusions in the red blood cell.

Zur Berechnung der physikalisch-chemischen Austauschvorgänge in der menschlichen und künstlichen Lunge - The calculation of the physical-chemical transfer processes in human and artificial lungs

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Synergism in the kinetic reactions of O2 and CO2 with human red blood cells*

Cited by 12 publications

References 23 publications

Rate limiting processes in the bohr shift in human red cells

Rate limiting processes in the bohr shift in human red cells

Numerical solution of partial differential equations describing the simultaneous O2 and CO2 diffusions in the red blood cell.

Zur Berechnung der physikalisch-chemischen Austauschvorgänge in der menschlichen und künstlichen Lunge - The calculation of the physical-chemical transfer processes in human and artificial lungs

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Synergism in the kinetic reactions of O₂ and CO₂ with human red blood cells*