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Wilhelm Bloch - One of the best experts on this subject based on the ideXlab platform.
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the Oxygen Dissociation Curve of blood in covid 19
American Journal of Physiology-lung Cellular and Molecular Physiology, 2021Co-Authors: Dieter Boning, Wolfgang M Kuebler, Wilhelm BlochAbstract:COVID-19 hinders Oxygen transport to the consuming tissues by at least 2 mechanisms: In the injured lung saturation of hemoglobin is compromised, in the tissues an associated anemia reduces the volume of delivered Oxygen. For the first problem increased hemoglobin Oxygen affinity (left shift of the Oxygen Dissociation Curve ODC) is of advantage, for the 2nd, however, the contrary is the case. Indeed a right shift of the ODC has been found in former studies for anemia caused by reduced cell production or hemolysis. This resulted from increased 2,3-biphosphglycerate (2,3-BPG) concentration. In 3 investigations in COVID-19, however, no change of hemoglobin affinity was detected in spite of probably high [2,3-BPG]. The most plausible cause for this finding is formation of methemoglobin, which increases the Oxygen affinity and thus apparently compensates for the 2,3-BPG effect. But this "useful effect" is cancelled by the concomitant reduction of functional hemoglobin. In the largest study on COVID-19 even a clear left shift of the ODC was detected when calculated from measurements in fresh blood rather than after equilibration with gases outside the body. This additional "in vivo" left shift possibly results from various factors (e. g. concentration changes of Cl-, 2,3-BPG, ATP, lactate, nitrocompounds, glutathione, glutamate, because of time delay between blood sampling and end of equilibration, or enlarged distribution space including interstitial fluid and is useful for O2 uptake in the lungs. Under discussion for therapy are the affinity-increasing 5-hydroxymethyl-2-furfural (5-HMF), erythropoiesis stimulating substances like erythropoietin, and methylene blue against MetHb formation.
Albert Frans - One of the best experts on this subject based on the ideXlab platform.
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comparative study of the oxyhaemoglobin Dissociation Curve of four mammals man dog horse and cattle
Comparative Biochemistry and Physiology Part A: Physiology, 1993Co-Authors: Thierry Clerbaux, Bruno Detry, Pascal Gustin, M L Cao, Albert FransAbstract:1. The entire Oxygen Dissociation Curve (ODC) and the effects of temperature, pH and 2,3-diphosphoglycerate (DPG) on this Curve, have been compared in four mammalians: man, dog, horse and cattle. 2. If the oxyphoric capacities are similar between these species (around 1.39 ml O-2/gHb), their P50, measured in standard conditions, i.e. at pH 7.4; pCO(2) 40 mmHg and T 37 degrees C, varies between 23.8 (+/-0.8) mmHg for the horse, 25.0 (+/-1.4) mmHg for cattle, 26.6 (+/-1.2) for man and 28.8 (+/-2.6) mmHg for the dog. 3. The higher dispersion of the dog's P50 is due to difference between breeds; in seven breeds investigated, the P50 ranges from 25.8 (spaniel) to 35.8 (hound). 4. We noted no sex difference in the four species. 5. The DPG level is confirmed to be low in cattle (
Oxygen exchange fraction defined as the difference in vol% between a pO(2) of 80 and 35 mmHg is, respectively, 3.6 (+/-0.6) vol% for cattle, 4.0 (+/-0.4) vol% for the horse, 5.5 (+/-0.5) vol% for man and 6.6 (+/-1.7) vol% for the dog. 7. The position and shape of the ODC, as well as T, DPG and pH effects, indicate that the haemoglobin of man and dog seem better adapted to O-2 delivery as compared to the horse and cattle.
M L Cao - One of the best experts on this subject based on the ideXlab platform.
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Chloride and inorganic phosphate modulate binding of Oxygen to bovine red blood cells
'American Physiological Society', 1994Co-Authors: Gustin P., M L Cao, Chenut F., Detry Bruno, Robert Annie, Ansay M., Frans Albert, Clerbaux ThierryAbstract:The influence of P-i and Cl on the equilibrium of Oxygen binding to bovine red blood cells was assessed by plotting the whole blood Oxygen Dissociation Curve measured under standard conditions with and without added KCl and K2HPO4. Both salts shifted the Oxygen Dissociation Curve to the right. This effect was more marked at the highest saturation levels. At a given saturation level, the anion-induced shift was linearly related to the concentration of salt added to the blood. Cl had a greater effect than P-i. The relationship between changes in Po-2 at 50% hemoglobin saturation (in Torr) and concentrations of ions added (in mmol/l) was equal to 0.0515[Cl] + 0.0302[P-i] (r(2) = 0.94; P < 0.001). These changes were not due to the hyperosmolality induced by salt addition, since sucrose added in place of salts was without effect on the measured parameters. The Oxygen exchange fraction expressed as percentage of saturation, i.e., the difference in hemoglobin saturation when Po-2 decreases from 130 to 40 Torr, was linearly correlated to added anion concentration (in mmol/l) {=0.102[Cl] + 0.059[P-i] (r(2) = 0.95; P < 0.001)}. No significant interaction between the anions was observed; their effects were purely additive. This original mechanism of controlling the Oxygen affinity of bovine blood may have clinical relevance: Cl and P-i could be used to increase Oxygen transport efficiency in hypoxic animals
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comparative study of the oxyhaemoglobin Dissociation Curve of four mammals man dog horse and cattle
Comparative Biochemistry and Physiology Part A: Physiology, 1993Co-Authors: Thierry Clerbaux, Bruno Detry, Pascal Gustin, M L Cao, Albert FransAbstract:1. The entire Oxygen Dissociation Curve (ODC) and the effects of temperature, pH and 2,3-diphosphoglycerate (DPG) on this Curve, have been compared in four mammalians: man, dog, horse and cattle. 2. If the oxyphoric capacities are similar between these species (around 1.39 ml O-2/gHb), their P50, measured in standard conditions, i.e. at pH 7.4; pCO(2) 40 mmHg and T 37 degrees C, varies between 23.8 (+/-0.8) mmHg for the horse, 25.0 (+/-1.4) mmHg for cattle, 26.6 (+/-1.2) for man and 28.8 (+/-2.6) mmHg for the dog. 3. The higher dispersion of the dog's P50 is due to difference between breeds; in seven breeds investigated, the P50 ranges from 25.8 (spaniel) to 35.8 (hound). 4. We noted no sex difference in the four species. 5. The DPG level is confirmed to be low in cattle (
Oxygen exchange fraction defined as the difference in vol% between a pO(2) of 80 and 35 mmHg is, respectively, 3.6 (+/-0.6) vol% for cattle, 4.0 (+/-0.4) vol% for the horse, 5.5 (+/-0.5) vol% for man and 6.6 (+/-1.7) vol% for the dog. 7. The position and shape of the ODC, as well as T, DPG and pH effects, indicate that the haemoglobin of man and dog seem better adapted to O-2 delivery as compared to the horse and cattle. -
Comparative-study of the Oxyhemoglobin Dissociation Curve of 4 Mammals - Man, Dog, Horse and Cattle
'Elsevier BV', 1993Co-Authors: Clerbaux Thierry, M L Cao, Gustin P., Detry Bruno, Frans AlbertAbstract:1. The entire Oxygen Dissociation Curve (ODC) and the effects of temperature, pH and 2,3-diphosphoglycerate (DPG) on this Curve, have been compared in four mammalians: man, dog, horse and cattle. 2. If the oxyphoric capacities are similar between these species (around 1.39 ml O-2/gHb), their P50, measured in standard conditions, i.e. at pH 7.4; pCO(2) 40 mmHg and T 37 degrees C, varies between 23.8 (+/-0.8) mmHg for the horse, 25.0 (+/-1.4) mmHg for cattle, 26.6 (+/-1.2) for man and 28.8 (+/-2.6) mmHg for the dog. 3. The higher dispersion of the dog's P50 is due to difference between breeds; in seven breeds investigated, the P50 ranges from 25.8 (spaniel) to 35.8 (hound). 4. We noted no sex difference in the four species. 5. The DPG level is confirmed to be low in cattle (
Harry Bard - One of the best experts on this subject based on the ideXlab platform.
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the effect of blood transfusion on the hemoglobin Oxygen Dissociation Curve of very early preterm infants during the first week of life
Seminars in Perinatology, 2002Co-Authors: Virginie De Halleux, Anita Truttmann, Carmen Gagnon, Harry BardAbstract:A study was conducted during the first week of life to determine the changes in P50 (PO2 required to achieve a saturation of 50% at pH 7.4 and 37 degrees C) and the proportions of fetal hemoglobin (HbF) and adult hemoglobin (HbA) prior to and after transfusion in very early preterm infants. Eleven infants with a gestational age < or = 27 weeks have been included in study. The hemoglobin Dissociation Curve and the P50 was determined by Hemox-analyser. Liquid chromatography was also performed to determine the proportions of HbF and HbA. The mean gestational age of the 11 infants was 25.1 weeks (+/- 1 weeks) and their mean birth weight was 736 g (+/- 125 g). They received 26.9 mL/kg of packed red cells. The mean P50 prior and after transfusion was 18.5 +/- 0.8 and 21.0 +/- 1 mm Hg (P = .0003) while the mean percentage of HbF was 92.9 +/- 1.1 and 42.6 +/- 5.7%, respectively. The data of this study show a decrease of hemoglobin Oxygen affinity as a result of blood transfusion in very early preterm infants prone to O2 toxicity. The shift in HbO2 Curve after transfusion should be taken into consideration when Oxygen therapy is being regulated for these infants.
Deniz Suna Erdincler - One of the best experts on this subject based on the ideXlab platform.
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the effect of pulsed ultrasound exposure on the Oxygen Dissociation Curve of human erythrocytes in in vitro conditions
Ultrasound in Medicine and Biology, 2002Co-Authors: Mehmet Ali Krpinar, Deniz Suna ErdinclerAbstract:Abstract The P 50 value, a marker for the behavior of the Oxygen Dissociation Curve (ODC) and values of 2,3-diphosphoglyceric acid (2,3-DPG), blood gases and acid base parameters (pH, PCO 2 , actual HCO 3 − , base excess, PO 2 , SO 2 ) and erythrocyte parameters (the number of erythrocyte, hematocrit and hemoglobin values) that are known to effect P 50 , were measured before and after ultrasound (US) exposure to examine the effect of pulsed US beams on the ODC of human erythrocytes. Venous blood samples taken from healthy subjects were sonicated at 0°C for 30 min by pulsed US beams with a constant frequency of 5 MHz. Experiments showed that the values of pH, actual HCO 3 − , standard HCO 3 − , base excess, 2,3-DPG and P 50 were changed considerably by pulsed US. Furthermore, correlation calculations were made to find out the relation between the P 50 values and the other parameters. As a result, a significant relation was found between P 50 values and the values of pH, actual HCO 3 − , PO 2 , SO 2 and 2,3-DPG. In conclusion, we can express that a highly significant increase occurs in P 50 value of venous blood after a pulsed US exposure at a constant frequency of 5 MHz for 30 min under in vitro conditions at 0 0 C. That is hemoglobin becomes suitable for deoxy (tense structure) conformation when blood affinity of O 2 is low. It means that hemoglobin becomes convenient for proton (H + ) and CO 2 binding. (E-mail: korpinar@istanbul.edu.tr)
