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As part of the American Medical Research Expedition to Everest in 1981, we measured hemoglobin concentration, red cell 2,3-diphosphoglycerate (2,3-DPG), Po2 at which hemoglobin is 50% saturated (P50), and acid-base status in expedition members at various altitudes. All measurements were made in expedition laboratories and, with the exception of samples from(More)
The inter-relationship between the interior subunit interfaces and the exterior diphosphoglycerate (DPG) binding region of the hemoglobin tetramer and the effects of a specific N-terminal acetylation on tetramer assembly have been evaluated. Tetrameric fetal hemoglobin F in the liganded state was found to dissociate to dimers much less than previously(More)
A precise and rapid procedure employing gel filtration on Superose-12 to measure the tetramer-dimer dissociation constants of some natural and recombinant hemoglobins in the oxy conformation is described. Natural sickle hemoglobin was chosen to verify the validity of the results by comparing the values with those reported using an independent method not(More)
Oxygen equilibrium curves of fresh, normal human blood have been measured by new methods which allow the control of pH, pCO2, and 2,3-diphosphoglycerate and which yield higher accuracy at the extremes of saturation than was possible previously. The curve determined by these techniques lies slightly to the right of the standard curve of Roughton et al.(More)
The N-terminal 18-amino acid sequence of the beta-chain of hemoglobin, as far as the end of the A helix, has been replaced by the corresponding sequence of the gamma-chain of fetal hemoglobin with the remaining sequence of the beta-chain retained (helices B through H). The gamma-beta-chain had the correct mass, and its entire sequence was established by(More)
The enzyme heme oxygenase, which exists in inducible (HO-1) and constitutive (HO-2) isoforms, catalyzes the degradation of heme to biliverdin and CO in mammalian tissues. CO has been implicated in the control of vascular tone in a manner similar to that for NO. In the present study, we investigated the contribution of the heme oxygenase/CO pathway to the(More)
Understanding of oxygen delivery by the microcirculation has been dominated by the unitary component analysis of Krogh and Erlangen focussed on oxygen transport mediated by single capillaries, oxygenation of tissue as a whole being extrapolated from findings on oxygen exchange in these vessels. This analysis is under revision since capillaries are not sole(More)
We compared rates of oxygen transport in an in vitro capillary system using red blood cells (RBCs) and cell-free hemoglobins. The axial PO(2) drop down the capillary was calculated using finite-element analysis. RBCs, unmodified hemoglobin (HbA(0)), cross-linked hemoglobin (alpha alpha-Hb) and hemoglobin conjugated to polyethylene-glycol (PEG-Hb) were(More)
We have measured plasma volume and cardiac index in rats after 50% isovolemic exchange transfusion with human hemoglobin cross-linked between the alpha-chains with bis(3,5-dibromosalicyl)fumarate (alpha alpha Hb) and with bovine hemoglobin modified with polyethylene glycol (PEGHb). alpha alpha Hb and PEGHb differ in colloid osmotic pressure (23.4 and 118.0(More)