scholarly journals The interplay between molten globules and heme disassociation defines human hemoglobin disassembly

2019 ◽  
Author(s):  
P.P. Samuel ◽  
M.A. White ◽  
W.C. Ou ◽  
D.A. Case ◽  
G.N. Phillips ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Global Analysis ◽  
Molten Globule ◽  
Guanidine Hydrochloride ◽  
Cell Lysis ◽  
Red Cells ◽  
Red Cell ◽  
Human Hemoglobin ◽  
Heinz Bodies ◽  
Molten Globules

AbstractHemoglobin functions as an oxygen transport protein, with each subunit containing a heme cofactor. We have developed a global disassembly model for human hemoglobin, linking hemin (ferric heme) disassociation and apo(heme-free)-protein unfolding pathways. The model was based on the evaluation of circular dichroism and visible absorbance measurements of guanidine hydrochloride-induced disassembly of holo (heme-bound)-hemoglobin and previous measurements of apohemoglobin unfolding. The populations of holo-intermediates and equilibrium disassembly parameters were determined quantitatively for adult and fetal hemoglobins. The key stages for disassembly into unfolded monomers are characterized by hemichrome intermediates with molten globule characteristics. Hemichromes, which occur when both hemin iron axial sites coordinate amino acids, are not energetically favored in native human hemoglobins. However, these hexacoordinate iron complexes are important for preventing hemin disassociation from partially unfolded species during early disassembly and late stage assembly events. Both our model evaluation and independent small angle X-ray scattering measurements demonstrate that heme disassociation during early disassembly leads to loss of tetrameric structural integrity. Dimeric and monomeric hemichrome intermediates occur along the disassembly pathway inside red cells where the hemoglobin concentration is very high. This prediction explains why in the red cells of patients with unstable hemoglobinopathies, misassembled hemoglobins often get trapped as hemichromes that accumulate into insoluble Heinz bodies. These Heinz bodies become deposited on the cell membranes and can lead to hemolysis. Alternatively, when acellular hemoglobin is diluted into blood plasma after red cell lysis, the disassembly pathway is dominated by early hemin disassociation events, which leads to the generation of higher fractions of apo-subunits and free hemin known to damage to the integrity of blood vessel walls. Thus, our model illuminates the pathophysiology of hemoglobinopathies and other disease states associated with unstable globins and red cell lysis, and provides insights into the factors governing hemoglobin assembly during erythropoiesis.SignificanceOur deconvolution and global analysis of spectral data led to both the characterization of “hidden” hemichrome intermediates and the development of a quantitative model for human hemoglobin disassembly/assembly. The importance of this mechanism is several-fold. First, the hemoglobin system serves as a general biological model for understanding the role of oligomerization and cofactor binding in facilitating protein folding and assembly. Second, the fitted parameters provide: (a) estimates of hemin affinity for apoprotein states; (b) quantitative interpretations of the pathophysiology of hemoglobinopathies and other diseases associated with unstable globins and red cell lysis; (c) insights into the factors governing hemoglobin assembly during erythropoiesis; and (d) a framework for designing targeted hemoglobinopathy therapeutics.

scholarly journals Heinz Body Anemia: An Ultrastructural Study. II. Red Cell Sequestration and Destruction

Blood ◽  
1965 ◽  
Vol 26 (4) ◽  
pp. 433-448 ◽  
Author(s):  
RICHARD A. RIFKIND
Keyword(s):  
Electron Microscope ◽  
Red Cells ◽  
Severely Injured ◽  
Red Cell ◽  
Intravascular Hemolysis ◽  
Heinz Bodies ◽  
Intracellular Digestion ◽  
Splenic Red Pulp ◽  
Selective Accumulation ◽  
Red Pulp

Abstract This study reports electron microscope observations on the process of red cell sequestration and destruction in the spleen and liver of the phenylhydrazine-treated rabbit. Damaged red cells are recognized by virtue of their Heinz bodies, a morphologic manifestation of the oxidative injury which they have sustained. Sequestration, in the spleen, involves the selective accumulation of damaged cells within the vascular spaces of the Billroth cords. Erythrophagocytosis and the intracellular digestion of red cells follows sequestration. More severely injured cells may undergo intravascular hemolysis within the splenic red pulp. In the liver, however, no evidence for the intravascular sequestration of injured red cells is observed. Damaged cells are removed directly from the sinusoidal blood by erythrophagocytosis. The selectivity of spleen and liver for red cells subjected to different degrees of injury is discussed in terms of the observed differences in the vascular architecture of the two organs.

scholarly journals pH Dependent Hemolytic Systems. II. Serum Factors Involved in Red Cell Lysis

Blood ◽  
1961 ◽  
Vol 17 (4) ◽  
pp. 474-490 ◽  
Author(s):  
STANLEY YACHNIN ◽  
FRANK H. GARDNER
Keyword(s):  
Human Serum ◽  
Cell Lysis ◽  
Cross Reaction ◽  
Red Cells ◽  
Red Cell ◽  
Cell Type ◽  
Serum Factors ◽  
Specific Serum ◽  
Human Sera ◽  
Ph Dependent

Abstract An analysis of the serum factors involved in the lysis and agglutination of artificially altered red cells in compatible human serum has been presented. Human sera have been found to vary widely in their capacity to hemolyze a panel of artificially altered red cells. These differences have been shown to be the result of a multiplicity of more or less specific serum factors for each altered red cell type. These factors have many of the properties commonly associated with classical antibody. These serum factors are different from complement and properdin. The range of specificity and the degree of cross reaction for these various serum factors have been analyzed. These serum factors are important in the consideration of the use of enzyme treated red cells for the detection of incomplete antibodies, and of certain acquired hemolytic states in man.

scholarly journals Granulocytes and Red Cell Lysis

Blood ◽  
1967 ◽  
Vol 30 (4) ◽  
pp. 485-494 ◽  
Author(s):  
RICHARD I. WALKER ◽  
J. C. HERION ◽  
S. W. SMITH
Keyword(s):  
Low Temperature ◽  
Hemolytic Activity ◽  
Protein Fraction ◽  
Basic Protein ◽  
Osmotic Fragility ◽  
Cell Lysis ◽  
Red Cells ◽  
Red Cell ◽  
Membrane Material

Abstract Intact granulocytes from man and rabbit hemolyze red cells in vitro. The hemolytic activity is related to the lysosomes. A highly-basic protein fraction from the lysosomes and lysosomal membrane material produce hemolysis in isosmotic buffered saline and increase the osmotic fragility of red cells. Sucrose does not inhibit this hemolytic activity but low temperature incubation and heparin do.

scholarly journals Re-evaluation of the structural integrity of red-cell glycoproteins during aging in vivo and nutrient deprivation

1987 ◽  
Vol 242 (1) ◽  
pp. 115-121 ◽  
Author(s):  
A Brovelli ◽  
C Seppi ◽  
A Bardoni ◽  
C Balduini ◽  
H U Lutz
Keyword(s):  
Blood Cells ◽  
Structural Integrity ◽  
Elevated Temperatures ◽  
White Cell ◽  
Red Cells ◽  
Glycophorin A ◽  
Red Cell ◽  
Density Separation ◽  
Human Red Blood Cells

Results presented in this paper show that removal of white-cell contaminations from human red blood cells by filtration through cellulose [Beutler, West & Blume (1976) J. Lab. Clin. Med. 88, 328-333] is a necessity whenever red cells are incubated at elevated temperatures or haemolysed after density separation. Omission of this precaution results in proteolysis of sialoglycoproteins in membranes from less-dense (young), but not dense (old), subpopulations. This proteolytic damage occurs during haemolysis of the cytoplasmic domain of glycophorin. A different type of proteolysis occurs if white-cell-contaminated red cells are incubated in the absence of glucose at elevated temperatures. Red cells release sialoglycopeptides. This process is stimulated by Ca2+ ions and is accompanied by the release of vesicles that differ from spectrin-free vesicles [Lutz, Liu & Palek (1977) J. Cell Biol. 73, 548-560]. This sialoglycopeptide release is dependent on white-cell contamination and is not required for the release of spectrin-free vesicles.

LACK OF EFFECT OF CORTICOSTEROIDS ON THE IN VIVO DISAPPEARANCE OF SULFHYDRYL-INHIBITED AND ANTIBODY-COATED ERYTHROCYTES

1964 ◽  
Vol 47 (3_Suppl) ◽  
pp. S28-S36
Author(s):  
Kailash N. Agarwal
Keyword(s):  
Red Cells ◽  
List Type ◽  
Red Cell

ABSTRACT Red cells were incubated in vitro with sulfhydryl inhibitors and Rhantibody with and without prior incubation with prednisolone-hemisuccinate. These erythrocytes were labelled with Cr51 and P32 and their disappearance in vivo after autotransfusion was measured. Prior incubation with prednisolone-hemisuccinate had no effect on the rate of red cell disappearance. The disappearance of the cells was shown to take place without appreciable intravascular destruction.

scholarly journals Determinants of Erythrocyte Size in Chronic Liver Disease

Blood ◽  
1969 ◽  
Vol 34 (6) ◽  
pp. 739-746 ◽  
Author(s):  
THOMAS M. KILBRIDGE ◽  
PAUL HELLER
Keyword(s):  
Bone Marrow ◽  
Liver Disease ◽  
Chronic Liver Disease ◽  
Peripheral Blood ◽  
Hepatic Cirrhosis ◽  
Alcoholic Cirrhosis ◽  
Clinical Findings ◽  
Red Cells ◽  
Red Cell ◽  
Cell Volumes

Abstract Serial determinations of red cell volumes were made with an electronic sizing device in 30 patients with hepatic cirrhosis. Variations in red cell volumes were correlated with other hematologic and clinical findings. The results of these studies suggest that volume macrocytosis in patients with alcoholic cirrhosis is either due to megaloblastosis of the bone marrow or to an accelerated influx of young red cells into the peripheral blood.

scholarly journals Reduction in massive postpartum haemorrhage and red blood cell transfusion during a national quality improvement project, Obstetric Bleeding Strategy for Wales, OBS Cymru: an observational study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sarah F. Bell ◽  
Rachel E. Collis ◽  
Philip Pallmann ◽  
Christopher Bailey ◽  
Kathryn James ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Quality Improvement ◽  
Blood Loss ◽  
Postpartum Haemorrhage ◽  
Red Cells ◽  
National Database ◽  
Care Bundle ◽  
Red Cell ◽  
National Quality ◽  
Red Cell Transfusion

Abstract Background Postpartum haemorrhage (PPH) is a major cause of maternal morbidity and mortality and its incidence is increasing in many countries despite management guidelines. A national quality improvement programme called the Obstetric Bleeding Strategy for Wales (OBS Cymru) was introduced in all obstetric units in Wales. The aim was to reduce moderate PPH (1000 mL) progressing to massive PPH (> 2500 mL) and the need for red cell transfusion. Methods A PPH care bundle was introduced into all 12 obstetric units in Wales included all women giving birth in 2017 and 2018 (n = 61,094). The care bundle prompted: universal risk assessment, quantitative measurement of blood loss after all deliveries (as opposed to visual estimation), structured escalation to senior clinicians and point-of-care viscoelastometric-guided early fibrinogen replacement. Data were submitted by each obstetric unit to a national database. Outcome measures were incidence of massive PPH (> 2500 mL) and red cell transfusion. Analysis was performed using linear regression of the all Wales monthly data. Results Uptake of the intervention was good: quantitative blood loss measurement and risk assessment increased to 98.1 and 64.5% of all PPH > 1000 mL, whilst ROTEM use for PPH > 1500 mL increased to 68.2%. Massive PPH decreased by 1.10 (95% CI 0.28 to 1.92) per 1000 maternities per year (P = 0.011). Fewer women progressed from moderate to massive PPH in the last 6 months, 74/1490 (5.0%), than in the first 6 months, 97/1386 (7.0%), (P = 0.021). Units of red cells transfused decreased by 7.4 (95% CI 1.6 to 13.2) per 1000 maternities per year (P = 0.015). Red cells were transfused to 350/15204 (2.3%) and 268/15150 (1.8%) (P = 0.001) in the first and last 6 months, respectively. There was no increase in the number of women with lowest haemoglobin below 80 g/L during this time period. Infusions of fresh frozen plasma fell and there was no increase in the number of women with haemostatic impairment. Conclusions The OBS Cymru care bundle was feasible to implement and associated with progressive, clinically significant improvements in outcomes for PPH across Wales. It is applicable across obstetric units of widely varying size, complexity and staff mixes.

BRIEF REPORT: Freeze-Cleaving of Red Cell Membranes in Paroxysmal Nocturnal Hemoglobinuria

Blood ◽  
1967 ◽  
Vol 30 (6) ◽  
pp. 785-791 ◽  
Author(s):  
RONALD S. WEINSTEIN ◽  
ROGER A. WILLIAMS
Keyword(s):  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Cell Membranes ◽  
Red Cells ◽  
Red Cell ◽  
Electron Microscopic ◽  
Structural Differences ◽  
Microscopic Studies ◽  
Red Cell Membranes

Abstract Electron microscopic studies on dried isolated red cell ghosts have been reported to show lesions associated with cell membranes in paroxysmal nocturnal hemoglobinuria (PNH). In this study, carbon-platinum replicas of membranes of freeze-cleaved, partially hydrated PNH red cells and isolated PNH cell ghosts failed to confirm the existence of these abnormalities. This suggests that the previously described lesions are the products of drying artifacts, although they may reflect hidden structural differences between PNH and normal red cell membranes.

Cytogenetic, anatomical and blood group studies of sheep twin chimaeras

1970 ◽  
Vol 175 (1039) ◽  
pp. 183-200 ◽  
Keyword(s):  
Blood Cell ◽  
Blood Group ◽  
Sex Chromosomes ◽  
Cell Types ◽  
In Utero ◽  
Red Cells ◽  
Cell Populations ◽  
Red Cell ◽  
X Protein ◽  
Blood Grouping

Karyotyping and blood grouping methods were used to identify sheep twin chimaeras. Evidence that an exchange of blood cell precursors (the origin of chimaerism) had taken place in utero was obtained by examining lymphocytes in culture and finding the chromosomes of both sexes in one individual, or by finding admixture of red cell antigens, haemoglobin or ‘X ’ protein. Where chimaerism of sex chromosomes was found the pairs had identical red cell types, but two separate populations of red cells were not always identifiable. The four females in the pairs studied were freemartins. No correlation was found between the relative proportions of the two red cell populations and those of the two white cell populations. In one pair of chimaeric ewes, breeding tests showed that the major red cell populations in each case were the true genetic type. In the freemartins no correlation was found between the degree of masculinity and the numbers of male lymphocytes. A possible correlation of masculinity with red cell proportions is discussed.

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