Search results for "erythrocyte"
showing 10 items of 370 documents
Anti-HIV-1 activity of inorganic polyphosphates.
1997
Human blood plasma, serum, peripheral blood mononuclear cells, and erythrocytes contain significant amounts of inorganic polyphosphates (ranging from 53 to 116 microM, in terms of phosphate residues). Here we demonstrate that at higher concentrations linear polyphosphates display cytoprotective and antiviral activity. Sodium tetrapolyphosphate and the longer polymers, with average chain lengths of 15, 34, and 91 phosphate residues, significantly inhibited human immunodeficiency virus type 1 (HIV-1) infection of cells in vitro at concentrations > or = 33.3 microg/ml (> or = 283-324 microM phosphate residues), whereas sodium tripolyphosphate was ineffective. In the tested concentration range,…
Distribution of chlorpromazine in a simplified blood influenced by various drugs
1973
The binding of chlorpromazine to erythrocytes and to albumin as influenced by other drugs was studied in a simplified blood (31.5±0.3% bovine erythrocytes, 4 g-% bovine serum albumin in 0.02 M phosphate buffer solution containing 0.15 M NaCl). the total concentration of chlorpromazine in the simplified blood was 10−4 M, the concentration of the displacing drugs was 10−3 M. After an incubation period of 3 h at 22° C the chlorpromazine concentration was determined in the albumin solution after centrifugation of the blood at 3000×g and in the aqueous phase after ultracentrifugation at 150000×g. Under control conditions 68.1±0.9% of chlorpromazine was bound to the erythrocytes, 28.5±0.9% was bo…
Physicochemical characterization of the fifth (C5), sixth (C6), seventh (C7), eighth (C8) and ninth (C9) component of guinea pig complement.
1971
A physicochemical characterization of the purified guinea pig complement components C5 to C9 is given. For this purpose the sedimentation rate, the diffusion coefficient, the molecular weight and the isoelectric point were determined and compared with the values already known for the guinea pig and human complement system. For the determination of the physicochemical parameters gel filtration on Sephadex G-200, ultracentrifugation applying a sucrose density gradient and thin-layer isoelectric focusing were used. By comparing the values of the human and guinea pig complement a remarkable similarity is shown.
An easy-to-use model for O2 supply to red muscle. Validity of assumptions, sensitivity to errors in data
1995
An easy-to-use capillary cylinder model of O2 supply to muscle is presented that considers all those factors that are known to be most important for realistic results: (1) red blood cell (RBC) O2 unloading along the capillary, (2) effects of the particulate nature of blood, (3) free and hemoglobin-facilitated O2 diffusion and reaction kinetics inside RBCs, (4) free and myoglobin-facilitated O2 diffusion inside the muscle cell, and (5) carrier-free region separating RBC and tissue. In a first approach, a highly simplified yet reasonably accurate treatment of the complex three-dimensional oxygen diffusion field in and next to capillaries is employed. As an alternative, a more realistic descri…
A preliminary study on the distribution of morphine and its glucuronides in the subcompartments of blood.
1998
[Abstract ] The distribution of morphine, morphine-3-glucuronide (M3G), and morphine-6-glucuronide (M6G) in whole blood, plasma, and packed erythrocytes was studied. Parameters investigated were the hematocrit values (10, 42, 44, and 71%) and the water content of the samples. The blood-to-plasma ratio of morphine concentrations was unaffected by variations in hematocrit and water content, whereas the corresponding ratios for M3G and M6G were strongly influenced. Ratios were 0.53 to 0.65 and 0.52 to 0.62 in specimens with average hematocrit values (42 and 44%, respectively), and the ratios were 0.81 or 0.89 (hematocrit 10%) and 0.27 or 0.28 (hemalocrit 71%) in blood samples with different he…
Hemoglobin dynamics in rat erythrocytes investigated by M�ssbauer spectroscopy
1991
Rats have been enriched in 57Fe and erythrocytes were isolated from the blood. Mössbauer absorption spectroscopy on the hemoglobin of these erythrocytes has shown rather similar dynamics as found earlier in crystals of myoglobin, in frozen solutions of human hemoglobin and in a number of other proteins. The results strongly indicate that the motion of the heme and presumably some part of the F-helix is mainly influenced by the average viscosity of the sample determined by a network of hydrogen bridges and other weak interactions. Extrapolations of Mössbauer results from protein crystals to proteins in their physiological surroundings seem to be suitable for heme proteins.
Encapsulation Response ofCiona intestinalis(Ascidiacea) to Intratunical Erythrocyte Injection
1997
Abstract Electron microscopic studies on the encapsulation induced by erythrocyte injection into the tunic of the ascidian Ciona intestinalis were carried out. The observations reported in the present paper complete the description previously given of capsule architecture and contribute to the characterization of the cells involved in the inflammatory reaction. The inflamed area is surrounded by an ample and peculiar “three-layered coat” respectively composed of flattened and packed extratunical hemocytes, the monolayered epithelium, and a layer of intratunical electron-dense particles. The latter are also clustered, variously arranged, and distributed in the tunic ground substance. The epi…
Phenoloxidase-dependent cytotoxic mechanism in ascidian (Styela plicata) hemocytes active against erythrocytes and K562 tumor cells.
1997
The cytotoxic activity against rabbit erythrocytes (RE) and human K562 tumor cells by Styela plicata hemocytes was significantly related to the phenoloxidase (PO) which converts phenols to quinone and initiates the melanogenic pathway. The effector hemocyte population, separated in a Percoll density gradient band, enriched in a granulocyte type named "morula cells", was examined with RE in a hemocyte cytotoxic assay and plaque forming cell assay. Inhibition experiments with the copper chelating agents 1-phenyl-2-thiourea and tropolone, the substrate analogue sodium benzoate and sodium ascorbate support the notion that hemocyte cytotoxic activity is a PO-dependent mechanism. Treatments of he…
A rapid rosetting method for separation of hemocyte sub-populations of Drosophila melanogaster.
2003
Hemocytes, cellular elements of the innate immune system in insects, play a crucial role in the cellular and humoral immune response. Although a significant amount of information has been collected on their differentiation and function, our understanding of hemocyte development is far from complete. Their characterisation is mostly based on morphological criteria. However, molecular markers were recently identified, defining functional subsets by the aid of monoclonal antibodies. Isolated subsets of hemocytes, in sufficient quantity and purity could help to analyse their development in vitro and also to further define their molecular characteristics. Here we describe an antibody-based roset…
The molecular basis of the low hemolytic activity of C4 molecules from low-C4 mice with IgM-coated erythrocytes.
1989
This study investigated the origin of the different hemolytic activity of two allotypes of murine C4, C4H (C4-high) and C4L (C4-low) in the presence of IgM-coated erythrocytes. C4H displayed a threefold higher hemolytic titer (expressed in hemolytic units/microgram protein) than C4L. No difference was found between c4H and C4L either in stability at 37 degrees C at different pH values and in the rate of C4H and C4L hydrolysis by activated Cl. The major functional difference was found in the covalent binding capacity to IgM-coated erythrocytes, with the amount of C4H bound being about threefold higher than that of C4L. A marked difference in the reactivity of the C4b fragment of C4H and C4L …