Range Of Hemoglobin Concentrations Research Articles

Sickle-cell hemoglobin: fall in osmotic pressure upon deoxygenation.

Macromolecules such as hemoglobin exert both kinetic and matrix effects on osmotic pressure. The kinetic osmotic pressure of sickle-cell hemoglobin is lost upon deoxygenation at physiological erythrocyte concentrations. The non-kinetic or matrix component of osmotic pressure remains relatively unchanged. Loss of thermal-osmotic activity during deoxygenation occurs throughout a hemoglobin concentration range between 2.5 and 35 g/100 ml. Deoxygenation of sickle-cell hemoglobin causes aggregation such that the matrix effect is unchanged but the kinetic (van't Hoff) effect nearly vanishes. A loss of intracellular osmotic pressure during deoxygenation could dehydrate the erythrocyte sufficiently to promote more rapid sickle-cell hemoglobin aggregation. Subsequently, complete gelation of these aggregates could cause additional water loss and thrust the sickled cell into an irreversible cycle. The osmotic pressure of normal hemoglobin does not change appreciably during deoxygenation and is essentially the same as the osmotic pressure of oxygenated sickle-cell hemoglobin.

13C NMR quantitation of polymer in deoxyhemoglobin S gels.

13C/1H magnetic double-resonance spectroscopy has been used to quantitate the amount of polymerized hemoglobin S in deoxygenated gels at 30 degrees C, for samples whose hemoglobin concentration range from 21 to 32 g/dl. Scalar- and dipolar-decoupled spectra and a 13C proton-enhanced dipolar-decoupled spectrum were recorded for each sample as was a scalar-decoupled spectrum for a matching oxyhemoglobin S control. The difference between the oxyhemoglobin S and deoxyhemoglobin S scalar-decoupled spectra was used to determine the polymer fraction, and this value was compared with the polymer fraction determined by using ultracentrifugation sedimentation on the same sample (assuming a two-phase model). The polymer fraction value determined by uncorrected sedimentation averaged 0.15 more than the value obtained from NMR. The discrepancy between the two techniques was largely removed when the analysis of the sedimentation data included a correction for depletion of hemoglobin in the supernatant or sol phase due to sedimentation of free molecules. The best fit to both the sedimentation and NMR data was obtained by using a solubility of deoxyhemoglobin S at 30 degrees C of 17.3 +/- 1 g/dl. These results indicate that the NMR techniques, which do not require separation of the sample into a sol phase and a pellet phase, provide quantitative information about the deoxyhemoglobin S polymer and will be useful for studies of sickle erythrocytes.

Synthesis of globin chains in sickle -thalassemia.

In five patients with sickle beta-thalassemia there was balanced alpha- and beta-globin synthesis in the bone marrow and decreased total beta-chain synthesis relative to that of alpha-chain in the peripheral blood. These findings are similar to those in patients with simple beta-thalassemia trait. Despite a range of hemoglobin concentrations from 6.8 to 12.5 g/100 ml in the patients with sickle thalassemia, there was no evidence of a significant excess of alpha-chains in the red cells of the bone marrow which could contribute to the hemolysis and anemia. In patients heterozygous for beta-thalassemia the capacity to synthesize beta-chain decreases more rapidly than that for alpha-chain. In nonthalassemic subjects the rates of beta- and alpha-chain synthesis decrease equally as the red cell matures. The beta(S)- and beta(A)-chains serve as convenient markers for globin synthesis due to the nonthalassemic and thalassemic alleles in patients with sickle beta-thalassemia. The unbalanced globin synthesis in the peripheral blood of these patients is explained by the decrease in relative synthesis of beta(S)-chain, in comparison with that of alpha-chain. This instability is not present in sickle cell trait. The beta(A)-chain synthesis was only unstable in the two patients who had the most marked anemia. The major mechanism for achieving balanced globin production in the bone marrow in the presence of one thalassemic gene appears to be increased synthesis of beta-chain due to the nonthalassemic allele. In addition, there may be a decrease of total alpha-chain synthesis in some patients.

Studies on the Relations between Molecular and Functional Properties of Hemoglobin: VII. KINETIC EFFECTS OF THE REVERSIBLE DISSOCIATION OF HEMOGLOBIN INTO SINGLE CHAIN MOLECULES

Abstract The kinetics of the reactions of human hemoglobin with carbon monoxide and oxygen has been studied in photochemical and rapid mixing experiments over a large range of hemoglobin concentration. When the reaction is initiated by rapid removal of the ligand from ligand-bound hemoglobin, the kinetics of the combination of hemoglobin with CO shows a marked concentration dependence in both the photochemical and the rapid mixing experiments. In dilute hemoglobin solutions (below 10-5 m in heme), dissociation of the ligand from oxyhemoglobin or carbonmonoxyhemoglobin is followed by slow changes (half-time of the order of seconds) in the properties of the system. These results lead to the following picture, which is also consistent with other as yet unexplained aspects of hemoglobin kinetics. (a) Ligand-bound hemoglobin dissociates reversibly into single chain molecules at concentrations below 10-5 m. (b) Deoxygenated hemoglobin has a much lower tendency to dissociate into single chain molecules, and there is no appreciable dissociation even at concentrations of the order of 10-6 to 10-7 m. (c) The association of deoxygenated α and β chains is a relatively slow process. Therefore, after sudden dissociation of the ligand from dilute hemoglobin solutions, the properties of the system, for a brief time, are those of a mixture of deoxygenated hemoglobin and deoxygenated α and β chains. (d) The properties of the single chain molecules obtained by dilution of ligand-bound hemoglobin are the same as those of isolated α and β hemoglobin chains as obtained by preparative procedures.

An improved transmission oximeter using interference filters

An oximeter using monochromatic light is described, and data are presented which reveal the accuracy of determinations made by the oximeter as compared with the Van Slyke method of analysis. The standard error of this comparison was ±0.2 per cent in the range of hemoglobin concentration from 10 to 17 Gm. per 100 ml. Also, the present cuvette-oximeter allows continuous recording of dye concentration for use in indicator-dilution curves for measurement of blood flow.

The Range of Hemoglobin Concentrations and Erythrocyte Counts in Healthy Men and Women

The Range of Hemoglobin Concentrations and Erythrocyte Counts in Healthy Men and Women Get access C. Ferdinand Nelson C. Ferdinand Nelson From the Department of Biochemistry, University of Kansas, Lawrence, Kansas Search for other works by this author on: Oxford Academic Google Scholar American Journal of Clinical Pathology, Volume 7, Issue 4, 1 July 1937, Pages 285–292, https://doi.org/10.1093/ajcp/7.4.285 Published: 01 July 1937 Article history Received: 20 November 1936 Published: 01 July 1937