Biorheology - Volume 18, issue 3-6

Authors: Witte, Siegfried

Article Type: Research Article

Abstract: Purified human fibrinogen conjugated in vitro with Fluorescein-Isothiocyanate (FITC) has been injected intravenously in rats (3–6.5 mg/100 g body weight). An intestinal loop with a well developed microvasculature was exposed into a transparent superfused chamber. By means of transmitting visible light and incident fluorescence illumination the microcirculatory blood vessels have been observed with an intravital fluorescence microscope. We found an accumulation of the fluorescent-labeled fibrinogen on the vascular wall beginning 5–15 minutes after the injection. Spots, streaks, nets and bands of labeled material appear with increasing intensity. They remain stationary at the vessel wall with undisturbed blood flow. A marked …affinity of such fibrinogen accumulation to the venular blood vessels has been found during an observation period of one hour. Topographically the labeled fibrinogen could be identified at the inner lining of the blood vessels, preferably at the interendothelial cell borders. Permeability processes of the labeled fibrinogen through the vessel walls into the perivascular tissue and into the lymph have also been found. The findings support some aspects of Copley’s concept of an endoendothelial fibrin lining. Show more

Keywords: Fibrinogen, Vitalmicroscopy, Fluorescence labeling, Microcirculation

DOI: 10.3233/BIR-1981-183-621

Citation: Biorheology, vol. 18, no. 3-6, pp. 579-588, 1981

Authors: Silberberg, A. | Klein, J.

Article Type: Research Article

Abstract: Two methods are applied to determine the thickness of an adsorbed soluble collagen layer on glass. One involves time of flow measurements in a glass capillary. Effects due to changes in contact angle and drainage, as the meniscus advances down the instrument, are eliminated. The results are compared with a direct force/distance curve determination for soluble collagen adsorbed to mica. At low pH layer thicknesses in excess of 325 nm are found, indicating that the collagen triple helices are standing end up on the surface. The amount of collagen adsorbed is only about 1 mg/m2 It can, therefore, be …calculated that some 12 nm separate the soluble collagen monomers. The surface layer is very diffuse. Raising the pH reduces layer thickness. Surface heat denaturation gives 70 nm thick layers. Show more

Keywords: Collagen, Glass, Protein Adsorption, Collagen Adsorption, Surface Layer Thickness, Surface wetting

DOI: 10.3233/BIR-1981-183-622

Citation: Biorheology, vol. 18, no. 3-6, pp. 589-599, 1981

Authors: Kukhareva, L.V. | Vorob’ev, V.I.

Article Type: Research Article

Abstract: The melting of collagen in rat tail tendons tanned by p-benzoquinone has been investigated. It was shown that the degree of tannage if it is not too high does not influence the tension-temperature dependence. Our data indicate that the isometric tension-temperature curves determined at any heating rate are not equilibrium. However the curves obtained at a moderate heating rate after preliminary partial melting of the fiber are practically coincident with the thermodynamically equilibrium melting curve. The rate of heating does not affect the relative contraction values derived from the isotonic length-temperature curves. Therefore the values of critical parameters of …the melting, critical stress and critical temperature, estimated from the isotonic data and from the tension-temperature curves of partially premelted fibers are equilibrium. The theoretical equilibrium tension-temperature dependence was first calculated from the Flory equation for the melting in fibrous proteins under load using the experimentally determined value of critical temperature. The resulting curve coincides with the experimental equilibrium curve accurate within the estimation of the number of polymer chains per unit of fiber cross-section. The applicability of the approach used in this study for the analysis of melting of various natural and synthetic polymer fibers is discussed. Show more

Keywords: Collagen Fibers, Rat Tail Tendons, Hydrothermal Contraction, Stress-Temperature Dependence, Equilibrium Melting and Critical Parameters

DOI: 10.3233/BIR-1981-183-623

Citation: Biorheology, vol. 18, no. 3-6, pp. 601-618, 1981

Authors: Maroudas, A. | Bannon, C.

Article Type: Research Article

Abstract: Swelling pressures of cartilage slices from human femoral heads and condyles have been measured against polyethylene glycol 20,000 solutions, standardised previously against mechanically applied pressure. In order to express the fixed charge density of cartilage on the basis of extrafibrillar water, the fraction of intrafibrillar water was determined from the partition of serum albumin between cartilage depleted of proteoglycans, and outside saline solution. The value for the intrafibrillar water was found to be 0.7 × collagen content. Provided the fixed charge density of cartilage slices is based on the equilibrium extrafibrillar water, the swelling pressure curve for cartilage coincides …with that for isolated proteoglycans, except at or near 100% hydration when the tensile stresses present in the collagen network counteract the osmotic pressure of the proteoglycans. These tensile stresses are relieved as soon as the tissue is compressed. The maintenance of the tissue hydration under load can thus be completely described in terms of a balance between the osmotic pressure of the proteoglycans and the applied pressure. Show more

Keywords: Swelling pressure, Osmotic pressure, Cartilage, Proteoglycan, Extrafibrillar water, Tissue stress

DOI: 10.3233/BIR-1981-183-624

Citation: Biorheology, vol. 18, no. 3-6, pp. 619-632, 1981

Authors: Kuroda, K. | Kamiya, N.

Article Type: Research Article

Abstract: Using the prototype of newly developed centrifuge-microscope loaded with a video camera to produce an unflickering image, we observed the behavior of cytoplasmic streaming in the young internodal cell of Nitella axilliformis during centrifugation. At 1500 rpm (250×g) the majority of the flowing endoplasm collected at the centrifugal end of the cell, when the boundary between the accumulated endoplasm and the cell sap was “horizontal” and flat. By slowing down the speed of rotation to 1000 rpm (110×g), a clearly recognizable streaming was started, in the form of a thin layer moving against the centrifugal force on one side …of the cell; and the endoplasm-cell sap boundary became tilted as if dragged by the stream overcoming the centrifugal force. When centrifugation was stopped, normal streaming soon resumed. The process was perfectly reversible. Prevention of streaming by cytochalasin B was shown to be due to the loss of motive force, and not to the increase in viscosity or gelation of the endoplasm. The streaming velocity-centrifugal force relation is not linear, which is explained by the thinning of the endoplasmic layer during centrifugation. Changes in streaming velocity induced by moderate centrifugal accelerations enabled us to estimate the motive force responsible for the streaming. It was calculated to be about 1 dyn·cm−2 , corresponding well with the data obtained by other methods. Show more

Keywords: Cytoplasmic streaming, Nitella, centrifuge-microscope, television

DOI: 10.3233/BIR-1981-183-625

Citation: Biorheology, vol. 18, no. 3-6, pp. 633-641, 1981

Authors: Yamamoto, Ryoichi | Fujihara, Suguru | Masuda, Yoshio

Article Type: Research Article

Abstract: A compression method for measurement of stress-relaxation proper- ties of the cell wall of storage tissues was developed, and the stress relaxation for the cell wall of Jerusalem artichoke tuber tissue was found to be represented by the equation S = b p · log ( t + T mp ) ( 1 + t p t + T mp ) t + T mp t p …( t + T op ) ( 1 + t p t + T op ) t + T op t p + c p where S is stress, t is time and bp , Top , Tmp and cp are constants. A synthetic auxin, 2,4-dichlorophenoxyacetic acid, induced cell wall loosening represented by a decrease in Top prior to the induction of expansion growth. Auxin and gibberellin synergistically stimulated the increase in bp and the decrease in cp in 2–3 days. Show more

Keywords: Stress-relaxation, Jerusalem artichoke, Auxin, Gibberellin, Cell wall

DOI: 10.3233/BIR-1981-183-626

Citation: Biorheology, vol. 18, no. 3-6, pp. 643-652, 1981

Authors: Charm, S.E. | Wong, B.L.

Article Type: Research Article

Abstract: Biological materials in flow are found to be degraded in flow through shear. Turbulent flow results in greater loss than streamline flow. It is possible to correlate a shear factor associated with flow with the Reynolds number. This preliminary study was carried out with lysozyme and covered a narrow range of Reynolds number. The plot of a shear factor vs the Reynolds number should be universal and independent of the material used to derive it. With this plot, it should be possible to determine the amount of inactivators expected for a material undergoing turbulent flow.

Keywords: Turbulence, shear, biomaterial, inactivation, Reynolds number, enzyme, lysozyme

DOI: 10.3233/BIR-1981-183-627

Citation: Biorheology, vol. 18, no. 3-6, pp. 653-657, 1981

Authors: Puchelle, Edith | Zahm, Jean-Marie | Aug, Françsois

Article Type: Research Article

Abstract: Viscoelasticity, protein content, and ciliary transport rate of sputum were studied in 3 groups of patients: 7 with recurrent bronchitis (group I), 13 “mild” chronic bronchitics (group II) and 19 “severe” chronic bronchitics (group III). The apparent viscosity (η o) and elastic modulus (G) were significantly higher in group I than group II and III. A four-fold decrease in secretory IgA to serum albumin ratio was observed in group III as compared to group II. The ciliary transport rate (Tr) on the depleted frog palate progressively decreased with the duration and severity of the disease. In group I, Tr remained …normal although 6 of the 7 sputa were outside predicted optimal viscoelastic range. These results suggest that other factors than viscosity and elasticity may control the mucociliary transport efficiency. Show more

DOI: 10.3233/BIR-1981-183-628

Citation: Biorheology, vol. 18, no. 3-6, pp. 659-666, 1981

Authors: Tamamushi, B.

Article Type: Research Article

Keywords: Liquid crystals, Rheology, Phase separation, Cell membrane

DOI: 10.3233/BIR-1981-183-629

Citation: Biorheology, vol. 18, no. 3-6, pp. 667-671, 1981

Authors: Papenfuss, Heinz-Dieter | Gross, Joseph F.

Article Type: Research Article

Abstract: The single-file flow of red blood cells in microcirculatory networks is studied theoretically. A phase-separation rule for the cells at the bifurcations is established and the flow-pressure drop relationship for the individual flexible cells is obtained from the work of Sutera and co-workers [Capillary blood flow. II. Deformable model cells in tube flow. Microvasc. Res. 2, 420–433, 1970]. Differences between tube and discharge hematocrit resulting from the kinematics of the blood flow in the capillaries and plasma skimming occurring at the bifurcations are taken into account The model provides flows, pressure drops, hematocrit values and relative viscosities in all …branches of the network. A purely fluid mechanical microhemoregulation is proposed. The mechanism of this peripheral blood regulation is the redistribution of red cells in the individual branches of the network corresponding to the morphology and the local flow rates, thus adjusting the hydraulic resistance to flow. Show more

Keywords: microhemodynarnics, hemorheology, microcirculation, network model, red cells

DOI: 10.3233/BIR-1981-183-630

Citation: Biorheology, vol. 18, no. 3-6, pp. 673-692, 1981