Evaluation of a new solid-phase immunoassay for alloantibody detection using bromelin-treated and untreated red blood cells

Iodination of the C-terminal half-molecule domain of ovotransferrin (OTF) causes a significant reduction in binding to transferrin receptors on chick reticulocytes when compared to the binding observed with holo-OTF or the N-terminal half-molecule domain. (In such studies binding of iodinated half-molecule is measured in the presence of equimolar unlabelled complementary half-molecule). In particular iodination of the C-terminal half-molecule domain by the solid-phase reagent Iodogen resulted in half the binding found when ICl was used. The iodinated N-terminal half-molecule domain labelled by either Iodogen or ICl showed consistently higher binding than was observed with the C-terminal half-molecule or Fe2OTF. Although the molecular basis for the reduced binding of these proteins relative to the N-terminal half-molecule has not been definitively established, the implication is that there is a Tyr in the C-terminal domain which is involved in receptor recognition and binding. Addition of one or more bulky iodine atoms to the Tyr interferes with the interaction. Tryptic peptide maps of unlabelled holo-OTF and half-molecule domains and of the half-molecule domains labelled by both ICl and Iodogen are presented. The maps indicate limited access of the tyrosine residues to iodination especially in the C-terminal half-molecule domain. Equilibrium binding experiments have been carried out to compare the Kd (the apparent dissociation constant for the interaction between OTF and the transferrin receptors on chick-embryo red blood cells) with the Bmax, (binding at infinite free-ligand concentration) for Fe2OTF labelled using ICl, Iodogen, Enzymobeads and Chloramine-T. The effect of labelling Fe2OTF by Bolton-Hunter reagent has also been assessed. These studies show that ICl appears to be the reagent of choice for labelling Fe2OTF and its half-molecule domains.

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Folate Forms in Red Blood Cell Lysates and in Intact Washed Red Blood Cells Are Stable for a Few Days During Refrigerated Storage

Current Developments in Nutrition ◽

10.1093/cdn/nzaa067_026 ◽

2020 ◽

Vol 4 (Supplement_2) ◽

pp. 1799-1799

Author(s):

Zia Fazili ◽

Neelima Papadugula ◽

Phuong Ngac ◽

Christine M Pfeiffer

Keyword(s):

Ascorbic Acid ◽

Red Blood Cells ◽

Blood Cells ◽

Solid Phase ◽

Storage Conditions ◽

Sample Type ◽

Refrigerated Storage ◽

Funding Sources ◽

Edta Blood ◽

Time Point

Abstract Objectives We investigated whether folate forms are stable in washed red blood cells (RBC) stored refrigerated for up to 9 days relative to RBC-lysates in ascorbic acid under the same storage conditions. Methods We prepared washed RBCs from freshly collected EDTA blood (n = 6 donors). For RBC-lysate 1, we diluted RBCs with saline (1/2 dilution), mixed well and prepared lysates (1/11 dilution) with 1% ascorbic acid (2 vials/time point; n = 12 vials/donor) for storage at 4°C for ≤ 9 days (baseline, 1, 2, 3, 6, and 9). For RBC-lysate 2, we aliquoted ∼0.5 mL washed RBCs (1 vial/time point; n = 5 vials/donor) for storage at 4°C for ≤9 days (1, 2, 3, 6, and 9). When refrigerated storage of samples was completed, RBC lysate 1 samples were frozen at −70°C, while the washed RBCs were diluted with saline (1/2 dilution), mixed well and RBC-lysates 2 were prepared (1/11 dilution) with 1% ascorbic acid (2 vials/time point; n = 10 vials/donor). All samples were stored at −70°C until analysis. At the time of analysis, we processed samples (2 replicates/time point; n = 2 days) for folate polyglutamate deconjugation using recombinant exo γ-glutamyl hydrolase, and conducted sample clean-up by automated solid phase extraction prior to analysis by LC-MS/MS. Results We found negligible losses of major folate forms after overnight refrigerated storage, and folate losses gradually increased over time (∼5% by day 6). The loss of 5-methyltetrahydrofolate and total folate (mean ± SD) after 2 days of storage for RBC lysate 1 was 1.2% ± 1.5% and 1.0% ± 1.3%, and for RBC-lysate 2 was 2.2% ± 1.1% and 2.7% ± 1.9%, respectively. The baseline concentration of non-methyl folate (sum of minor folate forms: 5-formyltetrahydrofolate [<LOD], tetrahydrofolate, and 5, 10-methenyltetrahydrofolate) was small (<3.0 nmol/L) in both sample types, and we noticed a slight increase (∼10%) after overnight storage. 5,10-Methenyltetrahydrofolate appeared to gradually convert to tetrahydrofolate upon storage in RBC-lysate 2 samples. We observed no noticeable changes for MeFox in either sample type. Conclusions Overnight refrigerated storage of RBC-lysates or washed RBCs is feasible and avoids notable losses of folate forms. Prolonged refrigerated storage promotes interconversions of minor folate forms. Funding Sources This work was supported by direct appropriations from U.S. Congress.

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Hemoglobin crystals of the red blood cells in the human renal cortex: electron microscopic observations of the renal lithiasis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083266 ◽

1978 ◽

Vol 36 (2) ◽

pp. 480-481

Author(s):

Kosuke Ueda ◽

Hiroto Washida ◽

Nakazo Watari

Keyword(s):

Red Blood Cells ◽

Blood Cells ◽

Renal Cortex ◽

Uranyl Acetate ◽

Osmic Acid ◽

Renal Lithiasis ◽

Electron Microscopic ◽

Hemoglobin C ◽

First Case ◽

Ultrathin Sections

IntroductionHemoglobin crystals in the red blood cells were electronmicroscopically reported by Fawcett in the cat myocardium. In the human, Lessin revealed crystal-containing cells in the periphral blood of hemoglobin C disease patients. We found the hemoglobin crystals and its agglutination in the erythrocytes in the renal cortex of the human renal lithiasis, and these patients had no hematological abnormalities or other diseases out of the renal lithiasis. Hemoglobin crystals in the human erythrocytes were confirmed to be the first case in the kidney.Material and MethodsTen cases of the human renal biopsies were performed on the operations of the seven pyelolithotomies and three ureterolithotomies. The each specimens were primarily fixed in cacodylate buffered 3. 0% glutaraldehyde and post fixed in osmic acid, dehydrated in graded concentrations of ethanol, and then embedded in Epon 812. Ultrathin sections, cut on LKB microtome, were doubly stained with uranyl acetate and lead citrate.

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Densitometric Identification of Primitive Erythroblasts After Reaction With Diaminobenzidine

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072083 ◽

1973 ◽

Vol 31 ◽

pp. 328-329

Author(s):

John A. Trotter

Keyword(s):

Red Blood Cells ◽

Analytical Method ◽

Blood Cells ◽

Guinea Pigs ◽

Specific Protein ◽

Visual Examination ◽

Hemoglobin Synthesis ◽

Peroxidatic Activity ◽

Small Density

Hemoglobin is the specific protein of red blood cells. Those cells in which hemoglobin synthesis is initiated are the earliest cells that can presently be considered to be committed to erythropoiesis. In order to identify such early cells electron microscopically, we have made use of the peroxidatic activity of hemoglobin by reacting the marrow of erythropoietically stimulated guinea pigs with diaminobenzidine (DAB). The reaction product appeared as a diffuse and amorphous electron opacity throughout the cytoplasm of reactive cells. The detection of small density increases of such a diffuse nature required an analytical method more sensitive and reliable than the visual examination of micrographs. A procedure was therefore devised for the evaluation of micrographs (negatives) with a densitometer (Weston Photographic Analyzer).

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Scanning electron microscopy of erythrophagocytosis by Entamoeba histolytica trophozoites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012480x ◽

1992 ◽

Vol 50 (1) ◽

pp. 880-881

Author(s):

Victor Tsutsumi ◽

Adolfo Martinez-Palomo ◽

Kyuichi Tanikawa

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Red Blood Cells ◽

Entamoeba Histolytica ◽

Causative Agent ◽

Blood Cells ◽

Protozoan Parasite ◽

Complex Phenomenon ◽

Great Capacity ◽

Scanning Electron

The protozoan parasite Entamoeba histolytica is the causative agent of amebiasis in man. The trophozoite or motile form is a highly dynamic and pleomorphic cell with a great capacity to destroy tissues. Moreover, the parasite has the singular ability to phagocytize a variety of different live or death cells. Phagocytosis of red blood cells by E. histolytica trophozoites is a complex phenomenon related with amebic pathogenicity and nutrition.

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Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162132 ◽

1990 ◽

Vol 48 (3) ◽

pp. 914-915

Author(s):

D.J.P. Ferguson ◽

A.R. Berendt ◽

J. Tansey ◽

K. Marsh ◽

C.I. Newbold

Keyword(s):

Plasmodium Falciparum ◽

Red Blood Cells ◽

Blood Cells ◽

Umbilical Vein ◽

Cell Types ◽

Amelanotic Melanoma ◽

Cytoplasmic Process ◽

Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

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