scholarly journals Hb Potomac (101 Glu replaced by Asp): speculations on placental oxygen transport in carriers of high-affinity hemoglobins

Blood ◽  
1978 ◽  
Vol 51 (2) ◽  
pp. 331-338 ◽  
Author(s):  
S Charache ◽  
R Jacobson ◽  
B Brimhall ◽  
EA Murphy ◽  
P Hathaway ◽  
...  
Keyword(s):  
Oxygen Transport ◽  
Oxygen Affinity ◽  
Normal Children ◽  
Tryptic Peptides ◽  
High Affinity ◽  
Female Carriers

Abstract Blood from a woman with unexplained erythrocytosis had increased oxygen affinity, but no abnormality could be detected by electrophoresis or chromatography of her hemolysate. Separation of the tryptic peptides of her beta chains disclosed two half-sized peaks in the regions of beta T- 11. The faster of these was abnormal, with the structure beta 101 Glu replaced by Asp. The new hemoglobin was called “Potomac.” Three of the proband's four surviving siblings and both of her children were carriers. Differences in the ratio of carrier: normal children born to male of female carriers of 23 other high-affinity hemoglobins were not significant. The high proportion of carriers in this kindred was probably due to chance alone, and not because high maternal oxygen affinity interfered with oxygen transport to fetuses with normal hemoglobin.

scholarly journals Hb Potomac (101 Glu replaced by Asp): speculations on placental oxygen transport in carriers of high-affinity hemoglobins

Blood ◽  
1978 ◽  
Vol 51 (2) ◽  
pp. 331-338
Author(s):  
S Charache ◽  
R Jacobson ◽  
B Brimhall ◽  
EA Murphy ◽  
P Hathaway ◽  
...  
Keyword(s):  
Oxygen Transport ◽  
Oxygen Affinity ◽  
Normal Children ◽  
Tryptic Peptides ◽  
High Affinity ◽  
Female Carriers

Blood from a woman with unexplained erythrocytosis had increased oxygen affinity, but no abnormality could be detected by electrophoresis or chromatography of her hemolysate. Separation of the tryptic peptides of her beta chains disclosed two half-sized peaks in the regions of beta T- 11. The faster of these was abnormal, with the structure beta 101 Glu replaced by Asp. The new hemoglobin was called “Potomac.” Three of the proband's four surviving siblings and both of her children were carriers. Differences in the ratio of carrier: normal children born to male of female carriers of 23 other high-affinity hemoglobins were not significant. The high proportion of carriers in this kindred was probably due to chance alone, and not because high maternal oxygen affinity interfered with oxygen transport to fetuses with normal hemoglobin.

scholarly journals Pregnancy in carriers of high-affinity hemoglobins

Blood ◽  
1985 ◽  
Vol 65 (3) ◽  
pp. 713-718
Author(s):  
S Charache ◽  
P Catalano ◽  
S Burns ◽  
RT Jones ◽  
RD Koler ◽  
...  
Keyword(s):  
Intrauterine Growth Retardation ◽  
Oxygen Affinity ◽  
Maternal Blood ◽  
Fetal Blood ◽  
Intrauterine Growth ◽  
High Affinity ◽  
Normal Fetus ◽  
High Oxygen Affinity ◽  
Female Carriers

Pregnancy in female carriers of abnormal hemoglobins with great avidity for oxygen provides a unique opportunity to assess the importance of the usual difference in oxygen affinity between fetal and maternal blood. Outcome of pregnancy was recorded for carriers of hemoglobins Bethesda, Osler, and Yakima, whose p50s (9.5, 9.1, and 12 mm Hg at pH 7.4) were far lower than that of a normal fetus (23 mm Hg at pH 7.3). Neither spontaneous abortions nor intrauterine growth retardation could be attributed to the presence of high oxygen affinity in the mothers. In vitro simulations suggested that neither maternal or fetal polycythemia alone was sufficient to adjust for perturbation of the normal situation, and increased uterine and/or fetal blood flow probably provided additional compensation.

scholarly journals Pregnancy in carriers of high-affinity hemoglobins

Blood ◽  
1985 ◽  
Vol 65 (3) ◽  
pp. 713-718 ◽  
Author(s):  
S Charache ◽  
P Catalano ◽  
S Burns ◽  
RT Jones ◽  
RD Koler ◽  
...  
Keyword(s):  
Intrauterine Growth Retardation ◽  
Oxygen Affinity ◽  
Maternal Blood ◽  
Fetal Blood ◽  
Intrauterine Growth ◽  
High Affinity ◽  
Normal Fetus ◽  
High Oxygen Affinity ◽  
Female Carriers

Abstract Pregnancy in female carriers of abnormal hemoglobins with great avidity for oxygen provides a unique opportunity to assess the importance of the usual difference in oxygen affinity between fetal and maternal blood. Outcome of pregnancy was recorded for carriers of hemoglobins Bethesda, Osler, and Yakima, whose p50s (9.5, 9.1, and 12 mm Hg at pH 7.4) were far lower than that of a normal fetus (23 mm Hg at pH 7.3). Neither spontaneous abortions nor intrauterine growth retardation could be attributed to the presence of high oxygen affinity in the mothers. In vitro simulations suggested that neither maternal or fetal polycythemia alone was sufficient to adjust for perturbation of the normal situation, and increased uterine and/or fetal blood flow probably provided additional compensation.

scholarly journals Hemoglobin Non-equilibrium Oxygen Dissociation Curve

2020 ◽  
Author(s):  
Rosella Scrima ◽  
Sabino Fugetto ◽  
Nazzareno Capitanio ◽  
Domenico L. Gatti
Keyword(s):  
Partial Pressure ◽  
Correct Diagnosis ◽  
Oxygen Affinity ◽  
Oxygen Dissociation Curve ◽  
Dissociation Curve ◽  
High Affinity ◽  
Oxygen Dissociation ◽  
Sequential Binding ◽  
Non Equilibrium

AbstractAbnormal hemoglobins can have major consequences for tissue delivery of oxygen. Correct diagnosis of hemoglobinopathies with altered oxygen affinity requires a determination of hemoglobin oxygen dissociation curve (ODC), which relates the hemoglobin oxygen saturation to the partial pressure of oxygen in the blood. Determination of the ODC of human hemoglobin is typically carried out under conditions in which hemoglobin is in equilibrium with O2 at each partial pressure. However, in the human body due to the fast transit of RBCs through tissues hemoglobin oxygen exchanges occur under non-equilibrium conditions. We describe the determination of non-equilibrium ODC, and show that under these conditions Hb cooperativity has two apparent components in the Adair, Perutz, and MWC models of Hb. The first component, which we call sequential cooperativity, accounts for ∼70% of Hb cooperativity, and emerges from the constraint of sequential binding that is shared by the three models. The second component, which we call conformational cooperativity, accounts for ∼30% of Hb cooperativity, and is due either to a conformational equilibrium between low affinity and high affinity tetramers (as in the MWC model), or to a conformational change from low to high affinity once two of the tetramer sites are occupied (Perutz model).

scholarly journals Hemoglobin Crete (beta 129 ala leads to pro): a new high-affinity variant interacting with beta o -and delta beta o -thalassemia

Blood ◽  
1979 ◽  
Vol 54 (1) ◽  
pp. 54-63 ◽  
Author(s):  
A Maniatis ◽  
T Bousios ◽  
RL Nagel ◽  
T Balazs ◽  
Y Ueda ◽  
...  
Keyword(s):  
Cell Morphology ◽  
Clinical Picture ◽  
Oxygen Affinity ◽  
High Oxygen ◽  
Red Cell ◽  
High Affinity ◽  
Contact Sites ◽  
Erythroid Hyperplasia ◽  
Proline Substitution ◽  
High Oxygen Affinity

Abstract Hemoglobin Crete, beta129 (h7)ala leads to pro, is a new mutant hemoglobin (Hb) with high oxygen affinity that was discovered in a Greek family in various combinations with beta- and deltabeta- thalassemia. The propositus, who presented an unusual clinical picture of an “overcompensated” hemolytic state, with erythrocytosis, splenomegaly, abnormal red cell morphology, and marked erythroid hyperplasia, appeared doubly heterozygous for Hb Crete and deltabeta- thalassemia. His red cells contained 67% Hb Crete and 30% Hb F, and the combination of these two hemoglobins resulted in a blood P50O2 of 11.2 mm Hg. A brother with Hb Crete trait (38% Hb Crete, 56% Hb A, blood P50O2 23.0 mm Hg) did not have significant erythrocytosis. Purified Hb Crete was heat-unstable and exhibited a high oxygen affinity, and a normal Bohr effect. We postulate that the beta 129 proline substitution disrupts the H helix, perturbing nearby residues involved in alpha 1 beta 1 contact sites of the Hb tetramer.

Application of an isolated heart model to investigate blood-oxygen delivery

1979 ◽  
Vol 237 (3) ◽  
pp. H348-H352
Author(s):  
P. W. Rand ◽  
C. V. Nelson ◽  
E. H. Lacombe ◽  
N. D. Barker ◽  
L. A. Pirone
Keyword(s):  
Therapeutic Potential ◽  
Isolated Heart ◽  
Oxygen Affinity ◽  
Rabbit Heart ◽  
Blood Oxygen ◽  
Affinity Modification ◽  
Heart Model ◽  
High Affinity ◽  
Hemoglobin Oxygen Affinity ◽  
Lactate Levels

To avoid the compensatory hemodynamic responses, which have limited interpretation of hemoglobin-oxygen affinity modifications in animal experimentation, an isolated blood-perfused rabbit heart model providing metabolic, functional, and vectorcardiographic measurements has been developed. Fixed-flow perfusions of unchanged or affinity-modified red blood cell suspensions were carried out to assess the benefits of high affinity during hypoxic hypoxia and of low affinity during posthypoxic recovery. Using fully saturated suspensions, the influence of affinity level during restricted flow and reperfusion was also studied. Higher myocardial oxygen consumption (MVO2) was associated with high-affinity blood during mild hypoxia and low-affinity blood during posthypoxic recovery. At low flows, heart rate and MVO2 tended to be lower in high-affinity perfusions, and to recover more completely during low-affinity reperfusions. Ventricular function, vectorcardiographic patterns, and lactate levels were affected by hypoxia and ischemia, but not by level of affinity. The relevance of these observations to the therapeutic potential of hemoglobin-oxygen affinity modification is discussed.

Temperature acclimation influences temperature-related behaviour as well as oxygen-transport physiology and biochemistry in the water flea Daphnia magna

2003 ◽  
Vol 81 (2) ◽  
pp. 237-249 ◽  
Author(s):  
Tobias Lamkemeyer ◽  
Bettina Zeis ◽  
Rüdiger J Paul
Keyword(s):  
Oxygen Consumption ◽  
Daphnia Magna ◽  
Oxygen Concentration ◽  
Oxygen Transport ◽  
Oxygen Affinity ◽  
Low Oxygen ◽  
High Concentration ◽  
Water Flea ◽  
Two Dimensional Gel Electrophoresis ◽  
Physiology And Biochemistry

To evaluate the role of temperature in oxygen transport in the water flea Daphnia magna, temperature-related behaviour as well as oxygen-transport physiology and biochemistry were investigated in animals long-term acclimated to moderate temperatures: 10, 20, or 30°C (normoxia) or 20°C (hypoxia). Study of the behaviour of animal groups within a normoxic thermal gradient showed their preferred temperatures and distribution patterns to be connected with acclimation conditions; for example, cold-acclimated individuals, with their relatively high metabolic rates and low oxygen-transport capacities, crowded at low temperatures where the oxygen concentration was high. One key to explaining these data is to assume a strategy of avoiding oxygen shortage. Both temperature and hypoxia acclimation also modified oxygen-transport variables such as oxygen consumption, ventilation and circulation rates, or the concentration and oxygen affinity of haemoglobin. Characteristic features of cold-acclimated D. magna were relatively high oxygen-consumption and heart rates and a low concentration and oxygen affinity of haemoglobin. Hypoxia-acclimated D. magna showed relatively low convective rates (frequency of thoracic-limb movements, heart rate) but a high concentration and oxygen affinity of haemoglobin. Additional experiments showed that independently of each other, temperature and ambient oxygen concentration modify haemoglobin quantity and quality, the former possibly acting via a temperature-induced hypoxia. The varying oxygen affinity is probably due to alterations of haemoglobin subunit composition, with the particular participation of subunits A, E, and G as revealed by two-dimensional gel electrophoresis.

scholarly journals The effect of bloodletting on exercise performance in a subject with a high-affinity hemoglobin variant

Blood ◽  
1983 ◽  
Vol 62 (6) ◽  
pp. 1159-1164 ◽  
Author(s):  
RM Winslow ◽  
WM Butler ◽  
JA Kark ◽  
HG Klein ◽  
W Moo-Penn
Keyword(s):  
Exercise Performance ◽  
Minute Ventilation ◽  
Oxygen Affinity ◽  
Cycle Ergometer ◽  
Blood Oxygen ◽  
High Loss ◽  
High Affinity ◽  
Blood Oxygen Affinity ◽  
The Subject ◽  
Undetermined Etiology

Abstract We studied two young army recruits with erythrocytosis. One had a variant hemoglobin with high affinity for oxygen (hemoglobin Osler, also known as Fort Gordon and Nancy, beta 145 Tyr leads to Asp). The other had normal oxygen affinity and erythrocytosis of undetermined etiology. Both were asymptomatic. We studied exercise capacity on a cycle ergometer before and after hemodilution. In the subject with high oxygen affinity, hemodilution resulted in reduced maximal work and increased heart rate at every work level. In addition, minute ventilation and arterial lactic acid increased, while anaerobic threshold decreased, indicating diminished oxygen supply to tissues. In contrast, the subject with normal oxygen affinity had no significant changes in exercise performance after hemodilution. These results suggest that when blood oxygen affinity is high, loss of efficiency in tissue oxygenation can be expected after phlebotomy or hemodilution. Therefore, it may be useful to measure blood oxygen affinity and exercise performance in polycythemic subjects in whom such procedures are intended to ameliorate symptoms of hyperviscosity.

Microvascular oxygen transport: impact of a left-shifted dissociation curve

1992 ◽  
Vol 262 (2) ◽  
pp. H517-H522 ◽  
Author(s):  
J. C. Stein ◽  
M. L. Ellsworth
Keyword(s):  
Oxygen Transport ◽  
Striated Muscle ◽  
Oxygen Affinity ◽  
Capillary Network ◽  
Retractor Muscle ◽  
Hemodynamic Parameters ◽  
Arterial Blood ◽  
Hemoglobin Oxygen Affinity ◽  
The Impact

The impact of an increased hemoglobin oxygen affinity (decreased P50) on oxygen transport was evaluated in capillaries of the retractor muscle under nonhypoxic (FIo2 = 0.30 and 0.21) and hypoxic (FIo2 = 0.10) conditions in hamsters with normal oxygen affinity [control; P50 = 26.1 +/- 1.0 (SD) mmHg, n = 12] and in hamsters with an increased oxygen affinity [treated; P50 = 16.2 +/- 1.6 (SD) mmHg, n = 7] induced by chronic short-term administration of sodium cyanate. Using in vivo video microscopy and computer-aided image analysis, we determined oxygen saturation (SO2) and associated hemodynamic parameters in both arteriolar (n = 30 control, 18 treated) and venular (n = 25 control, 17 treated) capillaries. In response to hypoxia, systemic arterial PO2 decreased to 29.6 +/- 6.0 (SD) mmHg in control animals and 24.7 +/- 3.8 (SD) mmHg in treated animals associated with abrupt decreases in systemic arterial blood pressure and increases in respiratory rate. The decrease in SO2 across the capillary network during nonhypoxic ventilation was 13.3% SO2 for control animals and 11.0% SO2 for treated animals. During hypoxic ventilation, the decrease in SO2 was 9.1% SO2 in control animals and 8.7% SO2 in treated animals. Hemodynamic parameters were not significantly different in the two groups during hypoxia. Estimated end-capillary PO2 was significantly lower in the treated animals. These data indicate that an increased oxygen affinity does not provide an obvious advantage for oxygen transport during hypoxia at the level of the capillary network in resting striated muscle; however, such an advantage might become apparent in the presence of an increased metabolic rate or a more severe hypoxic challenge.

Observations on the Respiratory Physiology and on the Haemoglobin of the Polychaete Genus Nephthys, with Special Reference to N. Hombergii (Aud. Et M.-Edw.)

1955 ◽  
Vol 32 (1) ◽  
pp. 110-125
Author(s):  
J. D. JONES
Keyword(s):  
Oxygen Transport ◽  
Sea Water ◽  
Oxygen Affinity ◽  
Exposure Period ◽  
Respiratory Physiology ◽  
Coelomic Fluid ◽  
Residual Water ◽  
The Difference ◽  
Dissociation Curves ◽  
Low Tension

1. Littoral representatives of the genus Nephthys are described as burrowing forms, able to irrigate their burrows with well-aerated sea water except when the sand is exposed by the tide. Then they are sealed in and have no access to oxygen outside the sand. 2. The concentration of dissolved oxygen in the sand water corresponds to a tension of about 7 mm. of Hg compared with a value about twice as great in the residual water in Arenicola burrows. 3. Extracellular pigments in the blood and coelomic fluid of Nephthys spp. are characterized as haemoglobins. The quantity of these pigments is shown to be inadequate as an oxygen store for the exposure period. 4. Dissociation curves for both pigments from N. hombergii are found to be approximately hyperbolic and the oxygen affinities relatively low. 5. The significance of the difference in oxygen affinity and the direction of the Bohr effect, between the vascular and coelomic pigments cannot yet be evaluated. 6. It is suggested that the Nephthys pigments are unspecialized and may function as a high-tension oxygen transport system only when the sand is covered by the sea. This is contrasted with the possibility of low-tension oxygen transport by the haemoglobin of Arenicola.

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