scholarly journals Negative charge distribution and density on the surface of oxygenated normal and sickle red cells

Blood ◽  
1981 ◽  
Vol 57 (4) ◽  
pp. 675-678 ◽  
Author(s):  
LJ Clark ◽  
LS Chan ◽  
DR Powars ◽  
RF Baker
Keyword(s):  
Charge Distribution ◽  
Electron Micrographs ◽  
Negative Charge ◽  
External Surface ◽  
Iron Hydroxide ◽  
Red Cells ◽  
Glutaraldehyde Fixation ◽  
Colloidal Iron ◽  
Membrane Area ◽  
Significant Difference

Abstract Negative charges on the external surface of red cells were visualized by colloidal iron hydroxide labelling of 50% of the membrane area after osmotic hemolysis and glutaraldehyde fixation. Counts were made over randomly selected areas on electron micrographs at 350,000 x magnification. Statistical analyses showed that at the 95% level of confidence there was no significant difference between oxygenated normal (AA) and sickle (SS) cells in either the distribution or the density of negative charges.

scholarly journals Negative charge distribution and density on the surface of oxygenated normal and sickle red cells

Blood ◽  
1981 ◽  
Vol 57 (4) ◽  
pp. 675-678
Author(s):  
LJ Clark ◽  
LS Chan ◽  
DR Powars ◽  
RF Baker
Keyword(s):  
Charge Distribution ◽  
Electron Micrographs ◽  
Negative Charge ◽  
External Surface ◽  
Iron Hydroxide ◽  
Red Cells ◽  
Glutaraldehyde Fixation ◽  
Colloidal Iron ◽  
Membrane Area ◽  
Significant Difference

Negative charges on the external surface of red cells were visualized by colloidal iron hydroxide labelling of 50% of the membrane area after osmotic hemolysis and glutaraldehyde fixation. Counts were made over randomly selected areas on electron micrographs at 350,000 x magnification. Statistical analyses showed that at the 95% level of confidence there was no significant difference between oxygenated normal (AA) and sickle (SS) cells in either the distribution or the density of negative charges.

The Fine Structure of Glycocalyx in Human Spermatozoa. A High Resolution Cytochemical Study

1973 ◽  
Vol 31 ◽  
pp. 640-641
Author(s):  
P. Hernández-Jáuregui ◽  
A. Sosa ◽  
A. González Angulo
Keyword(s):  
Negative Charge ◽  
Iron Hydroxide ◽  
Human Spermatozoa ◽  
Surface Coat ◽  
Cell Surfaces ◽  
Colloidal Iron ◽  
Cytochemical Study ◽  
Specific Permeability ◽  
Extracellular Glycoprotein ◽  
Mammalian Spermatozoa

Glycocalyx is the name given by Bennett to the extracellular glycoprotein coat present in some cell surfaces. It appears to play an important role in cell properties such as antigenicity, cell adhesivity, specific permeability, and ATP ase activity. In the sperm this coat can be directly related to such important phenomena as capacitation and fertilization. The presence of glycocalyx in invertebrate spermatozoa has already been demonstrated. Recently Yanagimachi et al. has determined the negative charges on sperm surfaces of mammalian spermatozoa including man, using colloidal iron hydroxide. No mention was made however of the outer surface coat as composed of substances other than those confering a negative charge. The purpose of this work was therefore to determine the presence of a glycocalyx in human spermatozoa using alcian blue and lanthanum staining.

scholarly journals ANIONIC SITES OF HUMAN ERYTHROCYTE MEMBRANES

1973 ◽  
Vol 57 (2) ◽  
pp. 373-387 ◽  
Author(s):  
Garth L. Nicolson
Keyword(s):  
Phospholipase C ◽  
Human Erythrocyte ◽  
Colloidal Particles ◽  
Iron Hydroxide ◽  
Glutaraldehyde Fixation ◽  
Anionic Sites ◽  
Colloidal Iron ◽  
Acetylneuraminic Acid ◽  
Induced Aggregation ◽  
Distributed Clusters

The effects of pH, trypsin, and phospholipase C on the topographic distribution of acidic anionic residues on human erythrocytes was investigated using colloidal iron hydroxide labeling of mounted, fixed ghost membranes. After glutaraldehyde fixation at pH 6.5–7.5, the positively charged colloidal particles were bound to the membranes in small randomly distributed clusters. The clusters of anionic sites were reversibly aggregated by incubation at pH 5.5 before fixation at the same pH. These results correlate with the distribution of intramembranous particles found by Pinto da Silva (J. Cell Biol. 53:777), with the exception that the distribution of anionic sites on a majority of the fixed ghosts at pH 4.5 was aggregated instead of dispersed. The randomly distributed clusters could be nonreversibly aggregated by trypsin or phospholipase C treatment of intact ghosts before glutaraldehyde fixation. Previous glutaraldehyde fixation prevented trypsin and pH induced aggregation of the colloidal iron sites. Evidence that N-acetylneuraminic acid groups are the principal acidic residues binding colloidal iron was the elimination of greater than 85% of the colloidal iron labeling to neuraminidase-treated cell membranes. Colloidal iron binding N-acetylneuraminic acid residues may reside on membrane molecules such as glycophorin, a sialoglycoprotein which contains the majority of the N-acetylneuraminic acid found on the human erythrocyte membrane.

Studies On Plasma Membranes

1967 ◽  
Vol 2 (4) ◽  
pp. 499-512
Author(s):  
E. L. BENEDETTI ◽  
P. EMMELOT
Keyword(s):  
Sialic Acid ◽  
Tight Junctions ◽  
Plasma Membranes ◽  
Iron Hydroxide ◽  
Chelating Agent ◽  
Colloidal Iron ◽  
Outer Leaflet ◽  
Liver Membranes ◽  
Junctional Complexes ◽  
Pre Treatment

Plasma membranes were isolated from rat liver and a transplanted rat hepatoma of the hepatocellular type. After glutaraldehyde fixation the membranes were treated with colloidal iron hydroxide (CIH) at pH 1.7, which was found to react specifically with the neuraminidase-sensitive sialic acid of the liver membranes. The CIH-reactive, neuraminidase-sensitive sialic acid, comprising 70% of the membrane-bound sialic acid, was exclusively located in the outer leaflet of the liver membranes as shown by the rather regular distribution of electron-dense CIH granules. This granular, asymmetric type of staining was also observed in the hepatoma membranes, which contained some 50% more sialic acid than did the liver membranes. In addition, the hepatoma membranes showed an intense and uniform staining by CIH of short segments of both membrane leaflets; the latter type of staining was but little impaired by neuraminidase pre-treatment. None of the junctional complexes of the liver membranes was stained by CIH. Tight junctions were very rarely observed in the hepatoma membrane preparations, and the desmosomes and intermediate junctions of these membranes not infrequently exhibited a loosened appearance exposing CIH-reactive neuraminidase-sensitive sialic acid at their opposite plates. This aspect could be induced in the desmosomes and intermediate junctions, but not in the tight junctions, by pre-treatment of the liver membranes with the chelating agent ethylenediaminetetra-acetate.

Expression of anionic sites on tumour cells at different stages of tissue invasion in vivo: a comparative study by X-ray microanalysis

1989 ◽  
Vol 94 (3) ◽  
pp. 561-566
Author(s):  
P.M. Evans ◽  
D.K. Suker ◽  
I. ap Gwynn
Keyword(s):  
Iron Hydroxide ◽  
Tumour Cells ◽  
Ehrlich Carcinoma ◽  
Similar Degree ◽  
Anionic Sites ◽  
Colloidal Iron ◽  
Cell Behaviour ◽  
X Ray ◽  
Invasion Stage

Quantification of colloidal iron hydroxide (CIH) labelling by X-ray microanalysis was used to investigate anionic sites at the surface of Ehrlich carcinoma cells from different locations in the mouse host. Individual tumour cells from peritoneal ascites suspensions (pre-invasion stage) varied up to threefold in their ability to bind CIH and a similar degree of intra-tumour heterogeneity was observed in different experimental animals. Pretreatment of the cells with neuraminidase confirmed that binding was at least partly due to surface sialic acid. Invasive cells isolated from mesenteric tumour nodules were also heterogeneous with regard to the availability of surface anionic sites, as were tumour cells adhering to the surface of the mesentery; however, in both these populations CIH binding was significantly greater on average than for free ascites tumour cells. The results suggest that surface anionic sites are determinants of the invasiveness of malignant cells in vivo, and that both the number and topography of these sites may be important in modulating tumour cell behaviour.

Abstract 2244: A Novel Micropace-Ablate Protocol Eliminates Coagulum Formation in Radiofrequency Ablation

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Bernard Lim ◽  
K.l. Venkatachalam ◽  
Susan Johnson ◽  
Arshad Jahangir ◽  
Samuel Asirvatham
Keyword(s):  
Surface Coverage ◽  
Negative Charge ◽  
Fibrin Clot ◽  
List Type ◽  
Rf Ablation ◽  
Persistent Problem ◽  
Significant Difference ◽  
Catheter Tip ◽  
Delivery Unit ◽  
Rf Energy

Radiofrequency (RF) ablation for cardiac arrythmias is an established curative therapy. However, catheter-tip coagulum formation leading to thromboembolic stroke is a persistent problem despite heparinization. Recent studies demonstrated an up to 70% incidence of thrombus formation on the catheter tip during ablation and a 10 % incidence of thromboembolic events. Catheter tip thrombus can impede the delivery of RF energy to the tissue, resulting in reduced efficacy and longer procedure times. Here we report on a novel method to prevent coagulum formation on ablation catheters by delivering a negative charge to the catheter tip to repel negatively charged fibrinogen molecules during RF ablation. A novel circuit was built with a charge delivery unit using a 9 voltage battery to deliver a fixed offset direct current charge, placed in parallel to the RF delivery unit for negative charge placement during RF delivery. In in-vivo canine experiments (n=50) standard 6/4, 8/5 ablation catheters and catheters with abraded tips were advanced from right femoral veins into atria and ventricles under intra-cardiac echo (ICE) and biplane fluoroscopic guidance. The dogs received 1 of 2 therapies: no RF energy delivered with and without negative charge delivery, RF energy delivery with and without negative charge delivery. The presence of thrombus was identified with ICE. The catheter tips were examined also macroscopically with visual inspection and also with field emission scanning electron microscopy (FESEM). FESEM of the catheter tips showed surface coverage of fibrin clot of the catheter tip to be 90 % for non-charged catheters compared to 0 % (p< 0.01) in negatively-charged catheters. There was no significant difference in surface coverage of fibrin clot between negatively-charged catheters with the abraded tips (98.8%) and non-charged catheters with smooth tips (90.7 %, p=ns). Clot volume formed on the catheter tip decreased with increased amount of charge. Application of a negative charge did not affect the quality of the intracardiac electrograms or induce malignant ventricular arrhythmias. Negative charge delivery during RF ablation is feasible and safe and can eliminate coagulum formation, potentially reducing thromboembolic complications.

Visualization of Charged Groups on the Surface of Rat Liver Nuclei

1974 ◽  
Vol 16 (3) ◽  
pp. 665-675
Author(s):  
ISMO VIRTANEN ◽  
JORMA WARTIOVAARA
Keyword(s):  
Rat Liver ◽  
Plasma Membranes ◽  
Iron Hydroxide ◽  
Nuclear Surface ◽  
Colloidal Iron ◽  
Rat Liver Nuclei ◽  
Ph Values ◽  
Liver Nuclei ◽  
Pre Treatment ◽  
Anionic Groups

Anionic groups on the outer surfaces of isolated rat liver nuclei were rendered visible in the electron microscope by staining with colloidal iron hydroxide at different pH values. At pH 1.8 the nuclei did not adsorb particles of stain, although plasma membranes left in the same preparation showed heavy labelling. After pretreatment with neuraminidase at pH 6 the plasma membranes were no longer stained. At pH 3.0 the nuclear surfaces also stained intensely. The staining pattern acquired at this pH did not appear to be changed by neuraminidase pre-treatment. With the staining method used, rat liver nuclear surfaces seemed to have no exposed sialic acid under isolation conditions which preserve the nuclear membranes and leave the ribosomes attached to the nuclear surface. However, at higher pH values other anionic groups seem to become dissociated and are stained with colloidal iron hydroxide.

scholarly journals ANIONIC SITES OF HUMAN ERYTHROCYTE MEMBRANES

1973 ◽  
Vol 59 (2) ◽  
pp. 395-406 ◽  
Author(s):  
Garth L. Nicolson ◽  
Richard G. Painter
Keyword(s):  
Iron Hydroxide ◽  
Membrane Surface ◽  
Erythrocyte Membranes ◽  
Temperature Dependent ◽  
Colloidal Iron ◽  
Acetylneuraminic Acid ◽  
Peripheral Protein ◽  
Human Erythrocyte Membranes ◽  
Γ Globulins ◽  
Topographic Distribution

The effects of affinity-purified antispectrin γ-globulins on the topographic distribution of anionic residues on human erythrocytes membranes was investigated using collo ida iron hydroxide labeling of mounted, fixed, ghost membranes. Antispectrin γ-globulins were sequestered inside ghosts by hemolysis and the ghosts were incubated for 30 min at 37°C and then fixed with glutaraldehyde. The topographic distribution of colloidal iron hydroxide clusters on ghosts incubated with low (&lt;0.05 mg/ml) or high (&gt;5–10 mg/ml concentrations of sequestered antispectrin was dispersed, but the distribution at intermediate concentrations (0.1–5 mg/ml) was highly aggregated. The aggregation of colloidal iron hydroxide binding sites was time and temperature dependent and required the sequestering of cross-linking antibodies (antispectrin Fab could not substitute for γ-globulin antibodies) inside the ghosts. Prior glutaraldehyde fixation or fixation at the time of hemolysis in antispectrin solutions prevented the antispectrin-induced colloidal iron site aggregation. The antispectrin reacted exclusively at the inner ghost membrane surface and the colloidal iron hydroxide bound to N-acetylneuraminic acid residues on the outer membrane surface which are overwhelming on the sialoglycoprotein glycophorin. These results were interpreted as evidence for a structural transmembrane linkage between the inner surface peripheral protein spectrin and the integral membrane component glycophorin.

Sign in / Sign up

Export Citation Format

Share Document