Improved O2 Transfer to Tissues During Deep Hypoxia in Rats with a Left-Shifted Blood O2 Dissociation Curve

1984 ◽  
pp. 199-208 ◽  
Author(s):  
Z. Turek ◽  
F. Kreuzer ◽  
B. E. M. Ringnalda ◽  
P. Scotto
Keyword(s):  
Dissociation Curve ◽  
O2 Dissociation Curve ◽  
O2 Transfer ◽  
O2 Dissociation

Distribution of Oxygen Tension in the Blood and Water Along the Secondary Lamella of the Icefish Gill

1972 ◽  
Vol 56 (2) ◽  
pp. 481-492
Author(s):  
G. M. HUGHES
Keyword(s):  
Current Flow ◽  
Dissociation Curve ◽  
Exchange Area ◽  
Gill Area ◽  
Secondary Lamella ◽  
Oxygen Tensions ◽  
Counter Current ◽  
O2 Dissociation Curve ◽  
Very High ◽  
O2 Transfer

1. Measurements of the gill area of two specimens of Chaenocephalus aceratus indicate that the resistance to water flow and overall exchange area are even less than had been supposed from work with other icefish. 2. Measurements of the oxygen tensions in the water and in blood entering and leaving the gills are used to determine the expected distribution of O2 tensions along a typical secondary lamella profile. The advantage of counter-current over co-current flow is clearly indicated by such analyses. 3. The absence of complications due to the O2 dissociation curve of the blood facilitates an extension of the analysis to different theoretical secondary lamellar profiles. It is shown that profiles similar to those usually found in fish gills are more efficient in maintaining O2 transfer. 4. Although the percentage utilization of O2 in the water passing through the gills is relatively low, the effectiveness of oxygenating the blood is very high in the icefish gill.

Simple, accurate equations for human blood O2 dissociation computations

1979 ◽  
Vol 46 (3) ◽  
pp. 599-602 ◽  
Author(s):  
J. W. Severinghaus
Keyword(s):  
Temperature Coefficient ◽  
Human Blood ◽  
Single Sample ◽  
Dissociation Curve ◽  
Hill’S Equation ◽  
Hill's Equation ◽  
O2 Dissociation Curve ◽  
O2 Dissociation

Hill's equation can be slightly modified to fit the standard human blood O2 dissociation curve to within plus or minus 0.0055 fractional saturation (S) from O less than S less than 1. Other modifications of Hill's equation may be used to compute Po2 (Torr) from S (Eq. 2), and the temperature coefficient of Po2 (Eq. 3). Variations of the Bohr coefficient with Po2 are given by Eq. 4. S = (((Po2(3) + 150 Po2)(-1) x 23,400) + 1)(-1) (1) In Po2 = 0.385 In (S-1 - 1)(-1) + 3.32 - (72 S)(-1) - 0.17(S6) (2) DELTA In Po2/delta T = 0.058 ((0.243 X Po2/100)(3.88) + 1)(-1) + 0.013 (3) delta In Po2/delta pH = (Po2/26.6)(0.184) - 2.2 (4) Procedures are described to determine Po2 and S of blood iteratively after extraction or addition of a defined amount of O2 and to compute P50 of blood from a single sample after measuring Po2, pH, and S.

Micromethod for dynamic determination of O2 dissociation curves using a PO2 electrode

1984 ◽  
Vol 56 (3) ◽  
pp. 795-797 ◽  
Author(s):  
M. C. Barnhart
Keyword(s):  
Human Blood ◽  
Time Course ◽  
Gas Mixtures ◽  
Dissociation Curve ◽  
Permeable Membrane ◽  
Standard Values ◽  
Dissociation Curves ◽  
O2 Dissociation Curve ◽  
O2 Dissociation

A nonspectrophotometric method is described for measurement of the O2 dissociation curve and O2 capacity of a 50-microliter sample of fluid. PO2 is recorded by a microprocessor as the sample is oxygenated and then deoxygenated by exposure to isocapnic gas mixtures across a gas-permeable membrane. The time course of deoxygenation and the O2 conductance of the membrane are used in calculating the O2 capacity of the sample and the dissociation curve. The method is sensitive and is best suited to samples of low O2 capacity and affinity. Measurements on buffer-diluted human blood agree with standard values.

Effects of chronic changes in hemoglobin-O2 affinity in rats

1979 ◽  
Vol 46 (4) ◽  
pp. 816-822 ◽  
Author(s):  
B. P. Teisseire ◽  
C. D. Soulard ◽  
R. A. Herigault ◽  
L. F. Leclerc ◽  
M. B. Laver
Keyword(s):  
Intraperitoneal Administration ◽  
Exercise Stress ◽  
Dissociation Curve ◽  
Toxic Side Effect ◽  
Physical Effort ◽  
O2 Concentration ◽  
Arterial Po2 ◽  
O2 Dissociation Curve ◽  
Sodium Cyanate ◽  
O2 Dissociation

We have assessed the characteristics of oxygen transport following chronic intraperitoneal administration of sodium cyanate (NaCNO, 90 mg/kg; P50 decreased), o-iodosodium benzoate (OISB, 300 mg/kg; P50 increased), or sodium chloride (NaCl; P50 unchanged) to rats at a rate of 5 times/wk for 16 wk. At the end of this period, the animals were exposed to a low inspired O2 concentration and were subjected to exercise stress. Hill's n50 at pH 6.90–7.60, hematocrit, and the saturation dependency of the Bohr effect (PCO2 constant) were altered by NaCNO only. Cyanate-treated rats gained less weight, probably due to a toxic side effect of the drug. Hypoxemia-induced lactatemia was greatest with a high P50 (OISB). Physical effort (swimming) was tolerated poorly at normal arterial PO2 when P50 was low (NaCNO). Although a left-shifted curve appears beneficial when FIO2 is reduced, reasons for the physiological advantage may be the result of other characteristics of the O2 dissociation curve, not P50 alone.

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