Biorheology - Volume 21, issue 1-2

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