Biorheology - Volume 27, issue 3-4

Authors: Chien, Shu | Sung, Lanping Amy

Article Type: Research Article

Abstract: The biorheological properties and behavior of red blood cells (RBCs), as other types of cells, have a biochemical and molecular basis. The shape maintenance and deformability of RBCs depend on the structural and functional integrity of the membrane proteins. These proteins are composed of transmembrane proteins inserted in the lipid bilayer, the skeletal proteins forming a network lining the membrane endoface, and the linking proteins which link together the other two types of proteins to form a three-dimensional protein structure to effect the complex and intricate biorheological functions of the RBC. The application of molecular biological techniques has led to …the establishment of the molecular structures of all major RBC membrane proteins and generated insights into the nature and energy of protein interactions in the membrane. Abnormalities or deficiencies of these proteins in hereditary disorders in humans and animals have offered opportunities to assess the rheological significance of each of these proteins and their interactions. Parallel molecular biological and biorheological studies on RBC membranes under a variety of conditions can provide the fundamental information required for theoretical modeling of RBC membrane rheology at the molecular level. Such interdisciplinary research will contribute to not only the elucidation of normal rheology of RBCs and other types of cells, but also the understanding of pathorheology of their disorders and the development of new methods of diagnosis and treatment. Show more

Keywords: Cytoskeleton, Erythrocyte deformability, Glycoproteins, Membrane proteins, Membrane viscoelasticity, Spectrin

DOI: 10.3233/BIR-1990-273-410

Citation: Biorheology, vol. 27, no. 3-4, pp. 327-344, 1990

Authors: Blank, Michael E. | Diedrich, Donald F.

Article Type: Research Article

Abstract: Light scattering measurements and scanning electron microscopy show that p-azidobenzylphlorizin (p-AzBPhz) causes changes in the shape and volume of human erythrocytes by at least two, dose-dependent mechanisms: At nominal concentrations above 5 μ M. the azide induces cell swelling by either enlarging a pre-existent channel or by creating pores between phase boundaries of the membrane through which salt and water enter, but sucrose remains excluded. However, over the range 0.03 to 0.3 μ M, in either isosmotic NaCl or KCl media, when fewer than 1 million molecules of azide are bound per cell, the ligand causes membrane deformations that convert …discocytes into cells resembling stage 2 echinocytes. Whereas a cell volume increase of about 10% accompanies these shape changes, (microhematocrit and electronic cell sizing measurements), no net influx of either Na+ or K+ during this stage of swelling was detectable. These cell alterations take place at p-AzBPhz concentrations which concurrently inhibit both chloride and 3-methoxyglucose equilibrium exchange transport. The results may indicate that when the membrane impermeable p-AzBPhz interacts with the anion and/or sugar transporter, some trans-membrane perturbation occurs which alters the cytoskeleton. Show more

Keywords: photoaffinity, sugar-anion transport, cytoskeleton, light scatter

DOI: 10.3233/BIR-1990-273-411

Citation: Biorheology, vol. 27, no. 3-4, pp. 345-355, 1990

Authors: Takakuwa, Yuichi | Ishibashi, Teruo | Mohandas, Narla

Article Type: Research Article

Abstract: The skeletal protein network of the red blood cell is thought to be important in regulating such membrane functions as deformability and stability. In the present study, we measured membrane deformability and stability of the resealed ghosts using an ektacytometer, a laser diffraction method, and identified the functional role of protein 4.1 and that of Ca2+ and calmodulin in maintaining membrane stability. To obtain direct evidence for a crucial role of protein 4.1 in maintaining membrane stability, we reconstituted protein 4.1-deficient membranes with purified protein 4.1. Although native membranes deficient in protein 4.1 had marked reduction in membrane stability, …reconstitution with increasing concentrations of purified protein 4.1 resulted in progressive restoration of membrane stability, providing direct evidence that protein 4.1 is essential for normal membrane stability. To determine if Ca2+ and calmodulin could modulate membrane properties, we measured membrane stability and deformability of resealed ghosts prepared in the presence of varying concentrations of Ca2+ and physiologic concentrations of calmodulin. Our data show that Ca2+ concentrations in the range of 1 to 100 μ M can markedly decrease membrane stability only in the presence of calmodulin, but not in its absence. In contrast, deformability decreased only at Ca2+ concentrations higher than 100 μ M, and calmodulin had no effect. Examination of the the effects of Ca2+ and calmodulin on various membrane protein interactions has enabled us to suggest that the observed changes in membrane stability may be partly related to the effects of Ca2+ and calmodulin on spectrin-protein 4.1-actin interaction. Show more

Keywords: erythrocyte, membrane stability, membrane deformability, protein 4.1, calmodulin, Ca2+

DOI: 10.3233/BIR-1990-273-412

Citation: Biorheology, vol. 27, no. 3-4, pp. 357-365, 1990

Authors: Donner, M. | Muller, S. | Stoltz, J.F.

Article Type: Research Article

Abstract: Fluorescence polarization is the most commonly used method to approach a property of cell membrane, the so-called “fluidity”. Whether time resolved determinations may be of potential interest to get precise information on the behaviour of fluorescent probes incorporated into biological membranes, steady state measurements are still the most accessible for biologists. Steady-state anisotropy value may be considered as a semi-quantitative indication of the cohesion of the lipid chains. However, meaningful interpretation of the anisotropy values requires a careful sample preparation and a suitable use of fluorescent probes. This paper reviews the properties and uses of several hydrophobic membrane fluidity probes. …In the case of intact cells, the potential interest of the association of fluorescence polarization with quenching fluorescence method in giving information on the “actual” membrane fluidity is outlined. Show more

Keywords: Fluorescence polarization, quenching, membrane fluidity probes, intact cells

DOI: 10.3233/BIR-1990-273-413

Citation: Biorheology, vol. 27, no. 3-4, pp. 367-374, 1990

Authors: Araiso, T. | Saito, H. | Shirahama, H. | Koyama, T.

Article Type: Research Article

Abstract: The viscosity and the molecular motion of phospholipid molecule in biological and artificial phospholipid bilayers were studied using picosecond fluorescence depolarization method with rod-like fluorophore, DPH. From the relationship between the viscosity in the lipid bilayer and the free space of phospholipid acyl-chain, it is concluded that the viscosity is determined mainly by the range of wobbling motion of the acyl-chain. Motion of polar head group was also measured by the same method with a newly synthesized fluorescent phospholipid, dipalmitoyl-phosphatidylumbelliferone. The rate and the range in the motion of head group were faster and larger than those of acyl-chain and …gave the viscosity of head group layer to be 0.03 poise, which was about one tenth of that of acyl-chain layer in the liquid crystalline phase. This fact indicates that the head group layer would not resist the lateral diffusion of molecules in membrane and that the lateral diffusion rate of molecules could be estimated from the viscosity in the acyl-chain layer. Show more

Keywords: membrane fluidity, picosecond fluorometry, molecular motion of phospholipid, viscosity in membrane surface, free-space model, lateral diffusion

DOI: 10.3233/BIR-1990-273-414

Citation: Biorheology, vol. 27, no. 3-4, pp. 375-387, 1990

Authors: Shiga, Takeshi | Tateishi, Norihiko | Maeda, Nobuji

Article Type: Research Article

Abstract: An optical spectroscopic system for determining the rate of oxygen release from flowing erythrocytes in microvessel is developed. The apparatus consists of following units attached to an inverted microscope. 1) A scanning spectrophotometer, equipped with a grating and a photon counter, was connected to an eyepiece of the microscope through a narrow light-guide, as to obtain the absorption spectrum (wave length range: 450 – 650 nm) of a focused spot ( ϕ = 7 μ m). 2) The velocity of erythrocyte flow was measured by dual-spots cross-correlation method, using two photomultipliers (connected to AID converter and microcomputer) …with two light-guides inserted into another eyepiece. 3) The diameter of vessel was estimated from digitized video-images, using a color image-processor. The ability of the apparatus was tested with (a) hemoglobin solution, (b) flowing erythrocyte suspension and (c) capillaries of rat mesentery. The rate of oxygen release through the vessel wall was calculated. A scanning spectrophotometer, equipped with a grating and a photon counter, was connected to an eyepiece of the microscope through a narrow light-guide, as to obtain the absorption spectrum (wave length range: 450 – 650 nm) of a focused spot ( ϕ = 7 μ m). The velocity of erythrocyte flow was measured by dual-spots cross-correlation method, using two photomultipliers (connected to AID converter and microcomputer) with two light-guides inserted into another eyepiece. The diameter of vessel was estimated from digitized video-images, using a color image-processor. Show more

Keywords: Absorption spectrum, Capillary, Erythrocytes, Hemoglobin, Oxygen release

DOI: 10.3233/BIR-1990-273-415

Citation: Biorheology, vol. 27, no. 3-4, pp. 389-397, 1990

Authors: Schmid-Schönbein, G.W. | Hakim, J.

Article Type: Introduction

DOI: 10.3233/BIR-1990-273-416

Citation: Biorheology, vol. 27, no. 3-4, pp. 399-399, 1990

Authors: Barroso-Aranda, Jorge | Schmid-Schönbein, Geert W.

Article Type: Research Article

Abstract: Recent research suggests that polymorphonuclear neutrophils (PMNs) play an important role in ischemic organ injury by adhesion to the endothelium and by expression of cytotoxicty via oxygen free radical formation. The number of activated circulating PMNs as measured by the reduction of nitroblue tetrazolium (NBT-positive PMNs) were shown to be closely associated with the trend towards irreversibility in hemorrhagic shock. Our objective was to investigate the effect of pentoxifylline (PTX) on two aspects of the PMN mediated injury: (a) adhesion to the endothelium, and (b) spontaneous circulating PMN activation as a risk factor in a Wiggers type hemorrhagic shock protocol …(35 mmHg mean arterial pressure for 90 minutes). The adhesion energy was estimated form the relative rolling velocity of individual PMNs on the endothelium of post-capillary venules in the rat mesentery before and after PTX treatment. The results indicate: (1) that PTX administration leads to a gradual reduction of the adhesion energy in a dose range between 1 to 100 mg/kg, and (2) it was possible to reduce significantly the spontaneous PMN activation in rats pretreated with PTX orally for at least 6 days (40 mg/kg per day). Although there were no significant differences in the PMN count between the PTX and the control group, the number of circulating NBT-positive PMNs before bleeding, as well as during the hypotensive period, was significantly lower in the PTX than in the control group. The 24-hour survival rate after hemorrhagic shock was improved from 50% in the untreated controls to 91% in the PTX group. These results suggest that manipulation of the circulating pool of PMN s by an agent that decreases the number of activated cells and reduces PMN adhesion to the endothelium, can significantly improve survival in this shock model. Show more

Keywords: Pentoxifylline, neutrophil activation, nitroblue tetrazolium test, neutrophil counts, neutrophil margination, rolling velocity

DOI: 10.3233/BIR-1990-273-417

Citation: Biorheology, vol. 27, no. 3-4, pp. 401-418, 1990

Authors: Hakim, Jacques

Article Type: Research Article

Abstract: The ability of neutrophils to adhere in a coordinated and reversible manner to the endothelium and other tissular components is crucial to their chemoattractant-induced locomotion towards relevant targets. Opsonins play a major role in the killing effect of neutrophils by inducing close adherence between the neutrophil and the target, thus maximizing the effect of the reactive oxygen species released by the stimulated neutrophils. Reactive oxygen species are released together with degradative enzymes and other killing proteins associated with neutrophil degranulation. This targeted neutrophil activity kills invading microorganisms but, in a similar way, may be harmful to organs, cells and molecules …that have been altered in some way or are involved in immune reactions. In some other pathological situations where body fluids contain proinflammatory agents, neutrophils may behave in a nontargeted and inappropriate manner. In such cases, adherence is often increased, thus slowing locomotion. Moreover, inflammatory agents often prime neutrophils for the oxidative burst induced by chemoattractants or other stimuli. The combined slow locomotion and hypersensitivity of primed neutrophils leads to a premature release of killing subtances which may affect blood components, vascular cells, connective tissue or whole organs . Any disturbance of neutrophil adherence is thus potentially harmful and must be recognized and suitably treated. Show more

Keywords: Human polymorphonuclear leukocyte, adherence, neutrophil activation, tissue injury

DOI: 10.3233/BIR-1990-273-418

Citation: Biorheology, vol. 27, no. 3-4, pp. 419-424, 1990

Authors: Wautier, Jean-Luc | Setiadi, Hendra | Vilette, Didier | Weill, Dominique | Wautier, Marie-Paule

Article Type: Research Article

Abstract: The adhesion of leukocytes to endothelium is a physiological phenomenon which is the first step for leukocyte emigration. The adhesion can be dramatically increased in pathological situations such as inflammation and vascular diseases. The molecular basis of leukocyte-endothelium interaction has been largely investigated in the last ten years. Using monoclonal antibodies it is possible to characterize the leukocyte adhesion molecule (LeuCAM) also named CD11/CD18 complex. These molecules responsible for leukocyte adhesion are heterodimers consisting of a common beta subunit and different subunit CD11a/CD18 corresponding to LFA-1; CD11b/CD18 to Macl/Mol; CD11c/CD18 to GP150-95. Beside these receptors, other leukocyte structures such as …the fibronectin receptors are involved in the adhesive process. On the endothelial cell side specialized structures implicated in leukocyte adhesion have been identified. Structures like Intercellular Adhesion Molecule (ICAM) are expressed on endothelial cells in the absence of stimulation, while other receptors Endothelial Leukocyte Adhesion Molecule (ELAM) are only detectable on activated endothelial cells. Cytokines such as IL-1 induced the expression of ELAM, increased the number of ICAM and Human Leukocyte Antigens (HLA) DR, DP, DQ. In various pathological circumstances, namely extracorporeal circulation, Acute Respiratory Distress Syndrome (ARDS), hypercholesterolemia and diabetes mellitus increased leukocyte adhesion has been reported and is potentially responsible for vascular damage. Therefore, the modulation of leukocyte-endothelial cell interactions is a possible target for antithrombotic and antiatherosclerotic therapy. Show more

Keywords: Leukocyte, Endothelial cells, Adhesion molecules

DOI: 10.3233/BIR-1990-273-419

Citation: Biorheology, vol. 27, no. 3-4, pp. 425-432, 1990