scholarly journals Surface properties of Entamoeba: increased rates of human erythrocyte phagocytosis in pathogenic strains.

1978 ◽  
Vol 148 (5) ◽  
pp. 1137-1143 ◽  
Author(s):  
D Trissl ◽  
A Martínez-Palomo ◽  
M de la Torre ◽  
R de la Hoz ◽  
E Pérez de Suárez
Keyword(s):  
Surface Properties ◽  
Entamoeba Histolytica ◽  
Human Erythrocyte ◽  
Comparative Studies ◽  
Phagocytic Activity ◽  
Human Erythrocytes ◽  
High Rate ◽  
Parasitic Protozoan ◽  
Microscopic Evaluation

The assertion that ingestion of human erythrocytes is restricted to invasive strains of Entamoeba histolytica has not been evaluated previously by comparative studies. In this report we describe the in vitro ingestion of human erythrocytes by pathogenic and nonpathogenic Entamoeba. Microscopic evaluation of erythrophagocytosis by eight different Entamoeba grown in culture revealed that strains of E. histolytica isolated from cases of human dysentery show a much higher rate of erythrocyte ingestion than nonpathogenic strains. However, all strains are able to phagocytize erythrocytes. The extremely high rate of phagocytic activity shown by pathogenic E. histolytica could be one of the properties related to the pathogenicity of this parasitic protozoan.

scholarly journals Multiple metabolic pools of phosphoinositides and phosphatidate in human erythrocytes incubated in a medium that permits rapid transmembrane exchange of phosphate

1987 ◽  
Vol 244 (1) ◽  
pp. 209-217 ◽  
Author(s):  
C E King ◽  
L R Stephens ◽  
P T Hawkins ◽  
G R Guy ◽  
R H Michell
Keyword(s):  
Plasma Membrane ◽  
Human Erythrocyte ◽  
Plasma Membranes ◽  
Age Distribution ◽  
Specific Radioactivity ◽  
Human Erythrocytes ◽  
Metabolic Compartmentation ◽  
To Come ◽  
Metabolic Heterogeneity

1. A Hepes-based medium has been devised which allows rapid Pi exchange across the plasma membrane of the human erythrocyte. This allows the metabolically labile phosphate pools of human erythrocytes to come to equilibrium with [32P]Pi in the medium after only 5 h in vitro. 2. After 5-7 h incubation with [32P]Pi in this medium, only three phospholipids, phosphatidic acid (PtdOH), phosphatidylinositol 4-phosphate (PtdIns4P) and phosphatidylinositol 4,5-bisphosphate (PtdIns4,5P2) are radioactively labelled. The concentrations of PtdIns4P and PtdIns4,5P2 remain constant throughout the incubation, so this labelling process is a reflection of the steady-state turnover of their monoester phosphate groups. 3. During such incubations, the specific radioactivities of the monoesterified phosphates of PtdIns4, PtdIns4,5P2 and PtdOH come to a steady value after 5 h that is only 25-30% of the specific radioactivity of the gamma-phosphate of ATP at that time. We suggest that this is a consequence of metabolic heterogeneity. This heterogeneity is not a result of the heterogeneous age distribution of the erythrocytes in human blood. Thus it appears that there is metabolic compartmentation of these lipids within cells, such that within a time-scale of a few hours only 25-30% of these three lipids are actively metabolized. 4. The phosphoinositidase C of intact human erythrocytes, when activated by Ca2+-ionophore treatment, only hydrolyses 50% of the total PtdIns4,5P2 and 50% of 32P-labelled PtdIns4,5P2 present in the cells: this enzyme does not discriminate between the metabolically active and inactive compartments of lipids in the erythrocyte membrane. Hence at least four metabolic pools of PtdIns4P and PtdIns4,5P2 are distinguishable in the human erythrocyte plasma membrane. 5. The mechanisms by which multiple non-mixing metabolic pools of PtdOH, PtdIns4P and PtdIns4,5P2 are sustained over many hours in the plasma membranes of intact erythrocytes are unknown, although some possible explanations are considered.

Insulin degradation by human erythrocyte lysates.

1981 ◽  
Vol 27 (4) ◽  
pp. 607-609 ◽  
Author(s):  
S G Nerurkar ◽  
K K Gambhir
Keyword(s):  
Human Erythrocyte ◽  
Insulin Binding ◽  
Radioreceptor Assay ◽  
Human Erythrocytes ◽  
Insulin Degradation ◽  
Optimum Conditions ◽  
Acid Buffer ◽  
Binding Data ◽  
Piperazineethanesulfonic Acid

Abstract In vitro hemolysates of isolated human erythrocytes degrade 125I-labeled insulin. Ten- to 100-fold dilutions of the hemolysate give a proportionately decreased degradation of 125I-labeled insulin at 37 degrees C, while dilutions of up to eightfold do not. Like the control, diluted "Buffer G" containing 5 mmol/L Tris and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer alone, more than 500-fold dilutions of the hemolysate or boiled hemolysate (in buffer) caused negligible (less than 1%) degradation of the labeled insulin. We conclude that accurate insulin-binding data during erythrocyte insulin radioreceptor assay under optimum conditions (Clin. Chem. 23: 1590-1595, 1977) depend on avoiding or minimizing hemolysis.

In Vitro Inhibition Effect and Molecular Docking Study of Curcumin, Resveratrol, and Quercetin on Human Erythrocyte Glutathione Transferase

2020 ◽  
Vol 15 (3) ◽  
pp. 197-205 ◽  
Author(s):  
Mine Aksoy ◽  
Muhammet Karaman ◽  
Pınar Güller ◽  
Uğur Güller ◽  
Ö. İrfan Küfrevioğlu
Keyword(s):  
Drug Resistance ◽  
Human Erythrocyte ◽  
In Silico ◽  
Glutathione Transferase ◽  
Natural Compounds ◽  
Human Erythrocytes ◽  
Antitumor Drugs ◽  
Multi Drug Resistance ◽  
Inhibition Effect

Background: Chemotherapy has shown varying success rates in the treatment of metastatic cancer in the last 50 years. One of the problems in the use of many chemotherapeutic agents is to increase the expression of glutathione transferase enzyme (GST; EC 2.5.1.18). Therefore, the development of GST inhibitors is important to improve the effectiveness of antitumor drugs and to overcome multi-drug resistance. Introduction: Glutathione S-transferases (GSTs) are a major member of enzymes serving in the detoxification of exogenous and endogenous substances. But, it has been reported that GSTs are overexpressed in many tumour cells, and it has been found to be related to developing resistance to anticancer drugs by these cells. The development of GST inhibitors is important to increase the efficacy of antitumor drugs and overcome multi-drug resistance. The aim of our study was to investigate the effect of natural compounds including curcumin, resveratrol, and quercetin on GST enzyme activity. We also aimed to specify inhibition mechanism of the compounds on human erythrocytes GST (hGST) with in silico study. Method: GST was purified from human erythrocytes using affinity chromatography (glutathione agarose). The enzyme purity was checked with SDS-PAGE. After the inhibitory effect of the curcumin, quercetin, resveratrol was investigated. Lastly, inhibition mechanisms of these natural compound were identified with induced-fit docking method. Result: GST was purified with 19.31% yield from human erythrocytes. In inhibition studies, Ki values of curcumin, quercetin, resveratrol were determined as 0.0021 ± 0.0008, 0.0257 ± 0.0011, 663.3301 ± 0.0936 µM respectively. According to our results, all natural products showed the inhibition effect and the order of inhibition is as follows: curcumin ˃ quercetin ˃ resveratrol. Conclusion: According to the results of the in vitro and in silico studies, it can be said that curcumin, quercetin, resveratrol are the inhibitors of human erythrocyte GST. In conclusion, these observations may be of great importance for the potential use of these natural compounds as chemopreventive agents.

Elemental analysis of human erythrocytes

1989 ◽  
Vol 47 ◽  
pp. 242-243
Author(s):  
S. A. Livesey ◽  
A. A. del Campo ◽  
E. S. Griffey ◽  
D. Ohlmer ◽  
T. Schifani ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Elemental Analysis ◽  
Human Erythrocyte ◽  
Spectroscopic Analysis ◽  
Model System ◽  
Human Erythrocytes ◽  
List Type ◽  
Chemical Fixation ◽  
Ethanol Dehydration ◽  
Lowicryl K4m

The aim of this study is to compare methods of sample preparation for elemental analysis. The model system which is used is the human erythrocyte. Energy dispersive spectroscopic analysis has been previously reported for cryofixed and cryosectioned erythrocytes. Such work represents the reference point for this study. The use of plastic embedded samples for elemental analysis has also been documented. The work which is presented here is based on human erythrocytes which have been either chemically fixed and embedded or cryofixed and subsequently processed by a variety of techniques which culminated in plastic embedded samples.Heparinized and washed erythrocytes were prepared by the following methods for this study :(1). Chemical fixation in 4% paraformaldehyde/0.25% glutaraldehyde/0.2 M sucrose in 0.1 M Na cacodylate, pH 7.3 for 30 min, followed by ethanol dehydration, infiltration and embedding in Lowicryl K4M at -20° C.

COMPARATIVE STUDIES OF THE POTENTIATION OF CORTICOTROPHIN ACTIVITY BY SEVERAL INACTIVE DERIVATIVES

1963 ◽  
Vol 42 (2) ◽  
pp. 209-213 ◽  
Author(s):  
Arthur I. Cohen ◽  
Edward H. Frieden
Keyword(s):  
Biological Activity ◽  
Comparative Studies ◽  
Free Amino ◽  
Hormonal Activity ◽  
Amino Groups

ABSTRACT A number of corticotrophin analogues have been prepared, some of which potentiate the biological activity of the untreated hormone in vitro. The free amino groups of corticotrophin appear to be essential not only for hormonal activity, but also for the interaction of the analogues with the tissue corticotrophin inactivating system which is assumed to account for the potentiating effect.

IN VITRO UPTAKE OF RADIOACTIVE 131I LABELLED L-TRIIODOTHYRONINE BY HUMAN ERYTHROCYTES AS AN INDEX OF THYROID FUNCTION

1960 ◽  
Vol XXXIV (II) ◽  
pp. 305-311 ◽  
Author(s):  
M. G. Woldring ◽  
A. Bakker ◽  
H. Doorenbos
Keyword(s):  
Thyroid Function ◽  
Incubation Time ◽  
Clinical Results ◽  
Human Erythrocytes ◽  
Red Cell ◽  
Clinical Value ◽  
Blood Samples ◽  
In Vitro Uptake

ABSTRACT The red cell triiodothyronine uptake technique as used in our hospital is described. Incubation time is of almost no importance. The temperature during incubation should be 37° C. Further improvement of the technique is obtained when all blood samples are brought up to 40 % haematocrit prior to incubation. Clinical results are discussed. It is yet too early to give a definite assessment of its clinical value, but it is definitely superior to the measurement of the BMR.

Preparation and In Vitro Evaluation of Resealed Erythrocytes as A New Trend in Treatment of Asthma

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
Mohammed Ibrahim ◽  
Alaa Zaky ◽  
Mohsen Afouna ◽  
Ahmed Samy
Keyword(s):  
In Vitro Release ◽  
Human Erythrocytes ◽  
The Body ◽  
Blood Levels ◽  
Time Interval ◽  
Burst Release ◽  
Prolonged Release ◽  
Nocturnal Asthma ◽  
Carrier Erythrocytes

Carrier erythrocytes are emerging as one of the most promising biological drug delivery systems investigated in recent decades. Beside its biocompatibility, biodegradability and ability to circulate throughout the body, it has the ability to perform extended release system of the drug for a long period. The ultimate goal of this study is to introduce a new carrier system for Salbutamol, maintaining suitable blood levels for a long time, as atrial to resolve the problems of nocturnal asthma medication Therefore in this work we study the effect of time, temperature as well as concentration on the loading of salbutamol in human erythrocytes to be used as systemic sustained release delivery system for this drug. After the loading process is performed the carrier erythrocytes were physically and cellulary characterized. Also, the in vitro release of salbutamol from carrier erythrocytes was studied over time interval. From the results it was found that, human erythrocytes have been successfully loaded with salbutamol using endocytosis method either at 25 Co or at 37 Co . The highest loaded amount was 3.5 mg/ml and 6.5 mg/ml respectively. Moreover, the percent of cells recovery is 90.7± 1.64%. Hematological parameters and osmotic fragility behavior of salbutamol loaded erythrocytes were similar that of native erythrocytes. Scanning electron microscopy demonstrated that the salbutamol loaded cells has moderate change in the morphology. Salbutamol releasing from carrier cell was 43% after 36 hours in phosphate buffer saline. The releasing pattern of the drug from loaded erythrocytes showed initial burst release in the first hour followed by a very slow release, obeying zero order kinetics. It concluded that salbutamol is successfully entrapped into erythrocytes with acceptable loading parameters and moderate morphological changes, this suggesting that erythrocytes can be used as prolonged release carrier for salbutamol.

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