Biorheology - Volume 21, issue 1-2

Authors: Ryan, Una S. | Ryan, James W.

Article Type: Research Article

Keywords: Endothelium, glycocalyx, pulmonary capillary, endothelial surface, angiotensin, pinocytosis

DOI: 10.3233/BIR-1984-211-210

Citation: Biorheology, vol. 21, no. 1-2, pp. 39-56, 1984

Authors: Katchalski-Katzir, Ephraim

Article Type: Research Article

Abstract: Some known conformational changes occurring in proteins and peptides are summarized and discussed. A novel nonradiative energy transfer technique, enabling evaluation of the conformation and intramolecular motility of polypeptides in solution, is described. The method should prove useful in the elucidation of the conformational motility prevailing in various biopolymers. The following three possible levels of flexibility in proteins are described: a . flexibility of chain segments; b . domain flexibility; and c . motion of side chains. Evidence is forwarded to show that these conformational motions actually occur in some proteins, as revealed by a number of physical chemical techniques. …The possible biological significance of the predicted conformational flexibility and conformational fluctuations of biopolymers is finally discussed. Show more

Keywords: Proteins, Polypeptides, Conformational changes, Conformational fluctuations, Domain flexibility, Segment flexibility, side-chain motion

DOI: 10.3233/BIR-1984-211-211

Citation: Biorheology, vol. 21, no. 1-2, pp. 57-74, 1984

Authors: Fukada, Eiichi

Article Type: Research Article

Abstract: Studies on piezoelectricity in biopolymers are reviewed with some examples. By measuring anisotropy of elastic and piezoelectric constants in fish skin, the direction of preferred orientation of collagen fibers is determined. Temperature and moisture dependence of real and imaginary parts of the piezoelectric constant observed for oriented film of fibrin gel indicates that temperature time equivalence holds for the piezoelectric relaxation. The piezoelectric constant for oriented film of polyhydroxybutyrate decreases above glass transition temperature, which is related to the elastic and dielectric relaxations. When α -helical molecules of poly-γ -methyl-L-glutamate are electrically oriented in ethylene dichloride solution and shear stress …is given by ultrasound, the piezoelectric polarization is observed. When the film of poly-γ -methyl-glutamate is wrapped around the femur of rat, the formation of new bone is produced. Show more

Keywords: Piezoelectricity, collagen, fibrin gel, polyhydroxybutyrate, polymethylglutamate, bone growth

DOI: 10.3233/BIR-1984-211-212

Citation: Biorheology, vol. 21, no. 1-2, pp. 75-84, 1984

Authors: Brooks, Donald Elliott

Article Type: Research Article

Abstract: A series of in vitro experiments testing the ability of tumor cells to withstand shear stresses typical of the circulation were carried out. Shearing suspensions of B16 murine melanoma cells in either a cone-plate viscometer or a tubing circuit caused loss of viability whose rate increased with increasing shear rate and shear stress. The killing rate did not depend on the ratio of the container area to volume of the viscometers, suggesting that interactions with the bounding surfaces were not responsible for the cell damage. The loss of viability was not due to the action of intracellular products released …during shearing. The results show that all the tumor cells examined were considerably more sensitive to shear than any of the blood cellular elements. Fluid shear stresses in the physiological range can kill tumor cells over time intervals of the order of minutes to hours, results very similar to the time courses observed for tumor cell destruction following injection into the circulation in animal models of metastasis. Show more

Keywords: metastasis, B16 melanoma, shear killing

DOI: 10.3233/BIR-1984-211-213

Citation: Biorheology, vol. 21, no. 1-2, pp. 85-91, 1984

Authors: Blombäck, Birger | Okada, Masahisa | Forslind, Bo | Larsson, Ulf

Article Type: Research Article

Abstract: We present data which show that fibrin gels are ordered network structures, the porosity of which is determined by the amount of thrombin being present during the activation step preceding gelation. On activation of fibrinogen, fibrinopeptides are released and simultaneously polymers are formed, obeying apparent first order kinetics. The pore size of the network is inversely related to the rate of polymer formation. It is proposed that at the time of gelation the polymers form an ordered lattice structure, which in the organism may serve as a biological interface.

Keywords: Fibrin, gels, structure, filters

DOI: 10.3233/BIR-1984-211-214

Citation: Biorheology, vol. 21, no. 1-2, pp. 93-104, 1984

Authors: Silberberg, Alex

Article Type: Other

DOI: 10.3233/BIR-1984-211-215

Citation: Biorheology, vol. 21, no. 1-2, pp. 105-105, 1984

Authors: Wayland, Harold

Article Type: Research Article

Abstract: Blood to lymph transport of macromolecules has been modeled by assuming a rather numerous population of small pores and a considerably smaller population of large pores across the microvascular walls. Such “black box” studies, however, are inherently incapable of identifying the precise pathways of movement. Electron microscopy has shown a variety of structures which might be identified as the “pores”. These include the intercellular junctions; vesicles which may shuttle across the endothelial cells; chains of vesicles forming open pathways; and, in the case of fenestrated capillaries, the fenestrae. With the exception of the shuttling vesicles, these structures have generally been …thought to be relatively static, representing a part of the architecture of the normal cell, albeit varying from organ to organ. Arterioles, capillaries and venules have been shown to have differing transport properties. Three possible barriers to transport are now recognized; a fibrous layer on the surface of the endothelial cells; the endothelial cells them.selves; and the basement membrane. Three properties of the macromolecule appear to be important in determining its ease of transmural passage; its size; its charge; and its chemical constitution. The simple “shuttling” model of transport by means of vesicles has recently been seriously questioned, and does not appear to be adequate to explain macromolecular transport. More and more evidence is accumulating to indicate that the chemical nature of the macromolecule is of considerable importance in determining whether or not it will transit the microvascular wall. Evidence will be shown that macromolecular transport is largely, if not entirely, a biochemically stimulated set of dynamic events, rather than being explicable on the basis of passive diffusion processes. The current state of our knowledge of these aspects of the problem of macromolecular transport are discussed, and suggestions made as to how to resolve some of the questions still unanswered. Show more

Keywords: Macromolecular transport, pinocytosis, endothelial receptors, fiber matrix, basement membrane

DOI: 10.3233/BIR-1984-211-216

Citation: Biorheology, vol. 21, no. 1-2, pp. 107-120, 1984

Authors: Witte, Siegfried

Article Type: Research Article

Abstract: It is our concept that the blood coagulation and fibrinolytic systems contribute to capillary permeability. By means of fluorescent intravital microscopy we measured in situ the permeability of proteins and fluorescent tracers through the walls of various kinds of microvessels (exposed rat mesentery). 1. Fluorescent dyes applied intravenously pass across the walls of all kinds of microcirculatory vessels into the perivascular tissue in animals having a state of hypocoagulemia in a shorter time than in normals. 2. Fluorescent-tagged fibrinogen accumulates at the vascular wall, especially at the inner lining of venules, thus marking free receptor sites for fibrinogen at these …places. Blocking the fibrinolytic activity of the blood augments the fibrinogen deposition. Pretreatment by heparin does not prevent it, which speaks against the fibrinogen-fibrin coagulation during the accumulation phenomenon. 3. In contrast to this behavior of fibrinogen, albumin, gammaglobulin, antithrombin III, plasminogen never accumulate at the vessel wall but pass through the vascular wall, mostly at venules. The speed and amount of the transvascular passage of these proteins depends on their molecular weight. 4. Fibronectin shares the same receptor sites at the inner lining of microcirculatory vessels as fibrinogen. It seems possible, therefore, that both proteins, fibrinogen and fibronectin, interact with each other at the endo-endothelial cell border. 5. A low molecular weight polypeptide fraction of factor VIII accumulates at the vascular wall similar to fibrinogen. At the same time it decreases the capillary permeability for serum proteins. Show more

Keywords: blood coagulation, capillary permeability, fibrinogen, fibronectin, vitalmicroscopy

DOI: 10.3233/BIR-1984-211-217

Citation: Biorheology, vol. 21, no. 1-2, pp. 121-133, 1984

Authors: Copley, Alfred L.

Article Type: Research Article

Abstract: The interface between the two portions of the ‘vessel-blood organ’, viz., the vessel wall and the circulating blood, is considered by the author to be the endoendothelial fibrin lining (EEFL). The view that the endothelium, consisting of the endothelial cells and the interendothelial cement substance, is the primary filtration barrier in capillary permeability (CP) is no longer tenable. There is considerable evidence that the primary barrier is an endocapillary protein layer, originally postulated by Danielli in 1940. Copley considered this layer to be identical with the EEFL formed in the more or less immobile portion of the plasmatic zone in …close proximity to the vessel wall. Processes of fibrin formation and fibrinolysis can occur there homeostatically, undisturbed by the flow of blood. The fibrinopeptides and plasminopeptides, freed at this site by the conversion of fibrinogen to fibrin and of plasminogen to plasmin, respectively, were reported by Copley et al in 1966 to augment CP. These peptides thus take part in the steadily occurring normal physiological CP. This is facilitated by the porosity of the EEFL due to the network or gel structure of fibrin strands. The author’s concept that the EEFL acts as the primary barrier, controlling transendothelial transport and transport across the basement membrane (BM), is discussed on the basis of older and recent findings by several investigators. In particular, the BM is dealt with in some detail as a barrier. Emphasis is placed on the existence of fibrin as a main constituent of the BM, hitherto not generally known. This was demonstrated by direct evidence in the production of (non-thrombocytopenic) vascular purpura with fibrin antiserum. Numerous tiny foci of fibrin(ogenin) gels are expected to stud the BM. Augmented capillary fragility (CF) due to increased fibrinolysis of many of these focal fibrin gels result in petechial hemorrhages. CF and CP are physical properties of the blood capillary wall which behave antagonistically and are controlled by fibrin formation and fibrinolysis, steadily occurring in the vascular layers including the EM. This barrier secures the integrity of the capillary wall by preventing extravasation of blood or hemorrhages. New experimental approaches to verify the detection of fibrin in the microstructure of the capillary wall are proposed. Moreover, hemorheological experimentation, models and treatments are needed to establish whether or not the EEFL is the crucial, critical barrier in CP, as proposed. Show more

Keywords: Basement membrane, capillary permeability, cement fibrin, endoendothelial fibrin lining (EEFL), endothelial cells, endothelium, fibrin gel, fibrinogenin gel, fibrino(geno)lysis, fibrinopeptides, interendothelial cement, petechiae, plasmatic zone, plasminopeptides, surface hemorheology, transcapillary transport, vessel-blood organ

DOI: 10.3233/BIR-1984-211-218

Citation: Biorheology, vol. 21, no. 1-2, pp. 135-153, 1984

Authors: Ryan, Una S. | Ryan, James W.

Article Type: Research Article

Abstract: Several enzymes, enzyme inhibitors, receptors and transport structures are situated on the luminal surface of endothelium. Some enzymes and transport systems are continuously active and, in effect, regulate the composition of blood moving downstream. Other components are latent. Their activities are not expressed in the absence of stimulus. Thus, endothelial cells injured by granulocytes or viral infection possess receptors for the Fc segment of IgG and for C3b, whereas normal endothelial cells do not. Both normal and injured endothelial cells express receptors for Clq. To visualize surface enzymes, inhibitors, receptors and transport structures, we have prepared surface replicas suitable for …high resolution EM. The surface replication technique, coupled with immunocytochemical procedures, facilitates studies of the topographies of surface enzymes such as angiotensin converting enzyme (ACE) and carboxypeptidase N (CPN). In addition, the replicas provide unique views of the glycocalyx, a cell coating previously believed to be amorphous but now seen to be a highly organized carpet-work under which surface enzymes, receptors, etc are embedded. Given its content of fibronectin, the glycocalyx may be the Clq receptor. Cells treated with antibodies to ACE or CPN show disarrayed glycocalyces and bind Fc and C3b. Latency of the Fc and C3b receptors may be owing to the physical barrier provided by the glycocalyx. Apparently, damage to the glycocalyx creates conditions favoring binding of immune complexes, complement activation and intravascular coagulation with loss of gradients between blood and parenchyma. Whether some non-thrombogenic properties of endothelium require an intact glycocalyx deserves consideration as does the role of the glycocalyx in regulating microvascular permeability. Show more

Keywords: Endothelial receptors, surface enzymes, projections, caveolae, glycocalyx

DOI: 10.3233/BIR-1984-211-219

Citation: Biorheology, vol. 21, no. 1-2, pp. 155-170, 1984

Authors: Smaje, L.H. | Swayne, G.T.G.

Article Type: Research Article

Abstract: A method for the measurement of compliance in mesenteric frog capillaries and rat venules is described briefly. The error introduced by capillary compliance in the measurement of hydraulic conductivity is then discussed in the light of these measurements and some of the recent literature on hydraulic conductivity are reassessed.

Keywords: Capillary, venule, compliance, hydraulic conductivity, filtration coefficient

DOI: 10.3233/BIR-1984-211-220

Citation: Biorheology, vol. 21, no. 1-2, pp. 171-179, 1984

Authors: Parker, K.H. | Winlove, C.P.

Article Type: Research Article

Abstract: The question of what components of the artery wall determine its hydraulic conductivity is approached in two different ways. Firstly, the hydraulic properties of an individual component, hyaluronate, are measured. It is shown that hyaluronate alone cannot account for the high resistance of the artery but hyaluronate entangled in a restraining filter has a hydraulic conductivity similar to that measured for the whole artery. Secondly, the hydraulic properties of porcine thoracic aortae which have been subjected to various extraction procedures are measured. Freezing and autoclaving have little effect, but alkali extraction increases the hydraulic conductivity by three orders of magnitude.

Keywords: hydraulic conductivity, solute transport, artery wall, hyaluronate

DOI: 10.3233/BIR-1984-211-221

Citation: Biorheology, vol. 21, no. 1-2, pp. 181-196, 1984

Authors: Caro, C.G. | Lever, M.J.

Article Type: Research Article

Abstract: Arterial wall mass transport has particularly attracted attention because it may be implicated in the development of arterial disease, including arteriosclerosis. A short review is presented of the structure of the arterial wall and of studies of mass transport within it. Recent findings confirm that mass transport occurs across the entire arterial wall apparently from the lumen to the adventitial lymphatics. Evidence has emerged of inhomogeneity of the distribution volume for extracellular tracers in different layers of the wall. An attempt is made to interpret results which indicate that distension per se of arteries and increase of medial smooth …muscle tone tend to compact the medial interstitium whereas pressure driven convection across the wall tends to expand that tissue. These findings imply a potentially important role of endothelial permeability, smooth muscle tone and luminal pressure in influencing solute transport in the wall and wall transport properties. Show more

Keywords: arterial wall mass transport, arterial haemodynamics, arterial interstitium

DOI: 10.3233/BIR-1984-211-222

Citation: Biorheology, vol. 21, no. 1-2, pp. 197-205, 1984

Authors: Hsiung, Cheng C. | Skalak, Richard

Article Type: Research Article

Abstract: The passive transport of water through the endothelial cell layer junctions is considered from the standpoint of hydrodynamic theories based on ultrastructural information. The local geometry of tight junctions based on molecular level forces and elastic membrane properties has been modeled and leads to estimates of the hydraulic resistance of the clefts. It is shown that the large resistance measured experimentally can be accounted for in this model. The transport of large macromolecules via vesicles which diffuse across the endothelial cell has been developed, but recent experimental data do not appear to support this mechanism as a primary pathway. Fused …vesicles forming an open channel appear to be rare. Leaky junctions, such as around dying endothelial cells or produced by cytoskeletal changes within the cells, may be important in control of endothelial permeability. Another kind of model is a fiber matrix model of the endocapillary layer, extending into the intercellular clefts which can also account for the molecular seiving properties of the endothelial cell layer but may produce a large resistance to water flux. Show more

Keywords: Endothelial cleft, permeability, cell-wall deformation, tight junctions

DOI: 10.3233/BIR-1984-211-223

Citation: Biorheology, vol. 21, no. 1-2, pp. 207-221, 1984

Authors: Silberberg, Alex

Article Type: Other

DOI: 10.3233/BIR-1984-211-224

Citation: Biorheology, vol. 21, no. 1-2, pp. 223-223, 1984

Authors: Carlstedt, I. | Sheehan, J.K.

Article Type: Research Article

Abstract: Cervical mucus glycoproteins (mucins) were extracted by using slow stirring in 6M-guanidinium chloride supplemented with proteinase inhibitors. Subsequent purification was achieved by isopycnic density-gradient centrifugation in CsCl/guanidinium chloride. The whole mucins (Mr 10 × 106 – 15 × 106 ) were degraded into ‘subunits’ (Mr 2 × 106 – 3 × 106 ) by reduction. Trypsin digestion of subunits afforded glycopeptides (‘T-domains’) with Mr 0.4 × 106 . The relationship between the intrinsic viscosity and Mr for the whole mucins and the fragments suggests that cervical mucins are linear flexible macromolecules. This view is …supported by hydrodynamic data. Show more

Keywords: cervical mucus, mucus glycoprotein, mucin, macromolecular structure, physical properties

DOI: 10.3233/BIR-1984-211-225

Citation: Biorheology, vol. 21, no. 1-2, pp. 225-233, 1984

Authors: Steiner, C.A. | Litt, M. | Nossal, R.

Article Type: Research Article

Abstract: Mucin glycoproteins are known to be the principal determinants of epithelial mucus rheology and hence of mucociliary transport rates. We are studying the structure of such glycoproteins using a model mucin purified from canine tracheal pouch secretions. Of particular interest is the effect on mucin structure of increased Ca++ such as occurs in certain disease states. Quasielastic laser light scattering was used to study the effect of Ca++ on the hydrodynamic radius of the mucin molecules. Scattering data from 0.3 mg/ml mucin solutions in physiological phosphate buffer containing 0,5 × 10−5 M, and 5 × 10−4 …M Ca++ were analyzed to obtain an average translational diffusion coefficient and the distribution of molecular radii for the dispersion. The effect of Ca++ was to decrease the average Stokes radius. The light scattering results are supported by rheologic measures of mucin gel viscoelasticity. Show more

Keywords: mucin, rheology, Ca++, tracheal mucus, macromolecular structure

DOI: 10.3233/BIR-1984-211-226

Citation: Biorheology, vol. 21, no. 1-2, pp. 235-252, 1984

Authors: Crowther, R.S. | Marriott, C. | James, S.L.

Article Type: Research Article

Abstract: The effects of mono-, di- and trivalent ions on the rheological properties of a purified mucus glycoprotein gel have been investigated. Monovalent ions increased the fluidity of the gels in a concentration dependent manner. The effect of calcium was pH dependent; at neutral pH values this ion produced a maximum in the gel viscoelasticity at a concentration of 0.5 mM, whilst at pH 5.0 the increase in viscoelasticity was sustained up to 3.0 mM. The same concentrations of copper (II) at pH 5.0 had a similar but greater effect on the viscoelasticity. Al3+ at pH 3.0 increased the viscoelastic …moduli throughout the range studied (0.1–2.0 mM), whereas iron made the gels more fluid at low concentrations, but increased the viscoelasticity to above control values at a concentration of 2.0 mM. Show more

Keywords: mucus, viscoelasticity, cations, gel structure

DOI: 10.3233/BIR-1984-211-227

Citation: Biorheology, vol. 21, no. 1-2, pp. 253-263, 1984

Authors: Puchelle, E. | Zahm, J.M.

Article Type: Research Article

Abstract: We studied the relations between the mucociliary beat frequency (MF) measured photometrically on the depleted frog palate and the rheological properties of sputum collected in patients with chronic obstructive pulmonary disease. MF was lower (p < 0.001) with sputa (11.3 ± 3.3 Hz) than with frog mucus (16.9 ± 3.3 Hz) used as controls. The relative transport rate (Tr) of sputa was closely correlated (r = 0.81, p < 0.001) to the relative MF. Significant correlations were observed between MF on the one hand and viscosity (r = −0.68, p < 0.01), elastic modulus (r = −0.70, p < 0.01) …and spinability (r = +0.49, p < 0.05) on the other. These results suggest that abnormalities in the rheological properties of bronchial secretions may impair the mucociliary transport rate by first decreasing the ciliary beat frequency. Show more

Keywords: Mucociliary transport, beat frequency, sputum, respiratory mucus, viscoelasticity, spinability

DOI: 10.3233/BIR-1984-211-228

Citation: Biorheology, vol. 21, no. 1-2, pp. 265-272, 1984

Authors: Yeates, D.B. | Larkridge, C.G. | Marrinelli, A. | Harshbarger, R.D. | Musselman, Rod P. | Pitt, B. | Raju, T.N. | Gerrity, T.R. | Lourenco, R.V.

Article Type: Research Article

Abstract: Measurements of the rate of mucociliary transport in the airways of the lower respiratory tract have been shown to be influenced by the techniques and protocols used. To avoid the effects associated with invasive techniques and anesthesia in animal models used to study the effect of maturation, drugs, disease, and inhaled pollutants on mucociliary transport we have developed unsedated dog and baboon models of mucociliary transport using radioaerosol techniques. As far as they have been tested these animal models of mucociliary transport react to drugs such as isoproterenol and atropine in the same manner as in man.

Keywords: mucus, cilia, lung, aerosols, baboons, dogs, anesthesia

DOI: 10.3233/BIR-1984-211-229

Citation: Biorheology, vol. 21, no. 1-2, pp. 273-283, 1984

Authors: Buchsbaum, G. | Sternklar, M. | Litt, M. | Grunwald, J.E. | Riva, C.E.

Article Type: Research Article

Abstract: The vitreous humor of the eye is modelled as a homogeneous viscoelastic sphere. The analysis provides a relation for the displacement amplitude and phase following oscillatory and step excitations, as functions of the storage and loss moduli of the vitreous gel, and allows calculation of the resolution requirements for a non-invasive optically-based diagnostic method for the viscoelastic properties of the vitreous.

Keywords: Vitreous humor, gel, viscoelastic, rheology, modelling

DOI: 10.3233/BIR-1984-211-230

Citation: Biorheology, vol. 21, no. 1-2, pp. 285-296, 1984