A Study on the Relationship Between the Oxygenation Velocity of the Red Blood Cell and the Flow Velocity in a Rapid Flow Method

Koyama, Tanetoshi; Mochizuki, Masaji

doi:10.2170/jjphysiol.19.534

Cited by 19 publications

(7 citation statements)

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“…2A). This finding is contradictory to that of previous reports, in which the oxygenation rate was accelerated by increasing the flow velocity (Koyama & Mochizuki, 1969) and by increasing the Reynolds number (Rice, 1980). This discrepancy may arise from the different methods used; the deoxygenation rate was in our experiments determined using hydrosulphite, which reduces the thickness of the stagnant layer (Coin & Olson, 1979) and thus makes our method rather less sensitive than others.…”

Section: Relation Between the Shapes Offlowing Erythrocytes And The Dcontrasting

confidence: 99%

The influence of deformation of transformed erythrocytes during flow on the rate of oxygen release.

Kon¹,

Maeda²,

Shiga³

1983

The Journal of Physiology

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SUMMARY1. The deoxygenation rates of transformed erythrocytes were compared with those ofnormal discocytes by both stopped-flow and continuous-flow methods. Echinocytic and spherostomatocytic transformations were induced by various anionic and cationic drugs, respectively, without altering the oxygen affinity of haemoglobin, the cell volume or the membrane fluidity.2. The echinocytic transformation reduced the deoxygenation rate at slow-flow velocities (50 cm/sec), as detected by the continuous-flow method. However, at higher flow velocities (150 cm/sec) the rate was similar to that seen in normal discocytes. A close correlation between the degree of echinocytosis, the retardation of deoxygenation rate and the increase of suspension viscosity were observed.3. Microscopic observation of flowing erythrocytes revealed that the echinocytes scarcely deformed at the slower flow velocity, but clearly deformed at the higher flow velocity to various shapes resembling the flowing discocytes.4. Transformation to spherostomatocytes had no effect on the deoxygenation rate, which was comparable with that of the discocytes, and even the higher flow force did not induce any deformation.5. The retarded deoxygenation and the increased viscosity of echinocytes was probably due to an augmented stagnant layer around the cells (i.e. an increase of the hydrodynamic effective volume); this layer was reduced when the echinocytes were deformed with increasing flow force.

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Section: Relation Between the Shapes Offlowing Erythrocytes And The Dcontrasting

confidence: 99%

The influence of deformation of transformed erythrocytes during flow on the rate of oxygen release.

Kon¹,

Maeda²,

Shiga³

1983

The Journal of Physiology

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“…Because this is a difficult procedure, the reported estimates of θ O2 vary from 0.9 to 2.7 mL O 2 mL −1 min −1 mmHg −1 . In addition, θ O2 depends on the hematocrit or hemoglobin concentration, and is reduced in anemia (214). Furthermore, θ O2 is affected by blood properties, as expressed by Holland et al (1977):

θ_{normalO 2} = k' c \cdot (0.0587 \cdot α_{normalO 2}) \cdot (1 - S_{normalO 2}) \cdot 0.01333 \cdot [Hb]

where k ′ c is the initial reaction velocity (mmol −1 s −1 ) of erythrocytes exposed to O 2 in solution; α O2 is the Bunsen solubility coefficient of O 2 ; S O2 is the (fractional) O 2 saturation of hemoglobin at the start of the stop-flow experiment; and [Hb] is hemoglobin content (g/100 mL).…”

Section: Structure-function Correlationsmentioning

confidence: 99%

Lung Structure and the Intrinsic Challenges of Gas Exchange

Hsia

Hyde

Weibel

2016

Comprehensive Physiology

159

142

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Structural and functional complexities of the mammalian lung evolved to meet a unique set of challenges, namely, the provision of efficient delivery of inspired air to all lung units within a confined thoracic space, to build a large gas exchange surface associated with minimal barrier thickness and a microvascular network to accommodate the entire right ventricular cardiac output while withstanding cyclic mechanical stresses that increase several folds from rest to exercise. Intricate regulatory mechanisms at every level ensure that the dynamic capacities of ventilation, perfusion, diffusion, and chemical binding to hemoglobin are commensurate with usual metabolic demands and periodic extreme needs for activity and survival. This article reviews the structural design of mammalian and human lung, its functional challenges, limitations, and potential for adaptation. We discuss (i) the evolutionary origin of alveolar lungs and its advantages and compromises, (ii) structural determinants of alveolar gas exchange, including architecture of conducting bronchovascular trees that converge in gas exchange units, (iii) the challenges of matching ventilation, perfusion, and diffusion and tissue-erythrocyte and thoracopulmonary interactions. The notion of erythrocytes as an integral component of the gas exchanger is emphasized. We further discuss the signals, sources, and limits of structural plasticity of the lung in alveolar hypoxia and following a loss of lung units, and the promise and caveats of interventions aimed at augmenting endogenous adaptive responses. Our objective is to understand how individual components are matched at multiple levels to optimize organ function in the face of physiological demands or pathological constraints.

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“…Koyama & Mochizuki (1969), Gad-el-Hak, Morton & Kutchai (1977) and Coin & Olson (1979) all found that on the time scale of red blood cell 02 uptake there may be incomplete mixing of fluid domains in dilute suspensions of red cells in turbulent flow. Gad-el-Hak et al (1977) found by laser anemometry that the flow of dilute suspensions of human erythrocytes through a 4 mm diameter flow tube was characterized by turbulence eddies with dimensions from about 1 mm down to a minimum of 70 /m.…”

Section: Introductionmentioning

confidence: 99%

The effect of the red cell membrane and a diffusion boundary layer on the rate of oxygen uptake by human erythrocytes

Huxley

Kutchai

1981

The Journal of Physiology

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SUMMARY1. This paper deals with the contributions ofthe red cell membrane and an external diffusion boundary layer ('unstirred layer') to the resistance to 02 entry into the red cell. Bovine serum albumin (BSA) was added to the extracellular fluid to enhance the effect of the diffusion boundary layer by diminishing both the solubility and the diffusivity of 02. The rate of 02 uptake by human red cells at various extracellular BSA concentrations was determined with a stopped-flow rapid-reaction apparatus.2. The initial rate of 02 uptake by the red cells was directly proportional to the diffusion coefficient of 02 in the extracellular fluid.3. If the diffusion boundary layer and the plasma membrane are considered as resistors in series, we estimate that 82-100 % of the total resistance to 02 entering the cell is due to the diffusion boundary layer. Our best estimate is that 95 % of the resistance resides in the diffusion boundary layer.4. Our bestestimate ofthe 02 permeability ofthe red cell membrane is 315 x 10-6 mmole/(cm2 see mmHg). With this permeability the membrane would account for only 5 % of the total resistance to 02 entering the cell. Partly because the membrane 02 diffusion resistance is a small fraction of the total resistance our estimate of the membrane resistance has a large standard deviation. Taking our estimate of the membrane resistance plus and minus its standard deviation we find that the membrane may account for 0-18 % of the total resistance to 02 entering the cell.5. The effective thickness ofthe diffusion boundary layer immediately after mixing is about 1-93 ,um according to our analysis.

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A Study on the Relationship Between the Oxygenation Velocity of the Red Blood Cell and the Flow Velocity in a Rapid Flow Method

Cited by 19 publications

References 1 publication

The influence of deformation of transformed erythrocytes during flow on the rate of oxygen release.

The influence of deformation of transformed erythrocytes during flow on the rate of oxygen release.

Lung Structure and the Intrinsic Challenges of Gas Exchange

The effect of the red cell membrane and a diffusion boundary layer on the rate of oxygen uptake by human erythrocytes

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