Biorheology - Volume 10, issue 4

Authors: Ehrly, A.M. | Lung, G.

Article Type: Research Article

DOI: 10.3233/BIR-1973-10411

Citation: Biorheology, vol. 10, no. 4, pp. 577-583, 1973

Authors: Dintenfass, L. | Stewart, J.H. | Milton, G.W. | Forbes, C.D.

Article Type: Research Article

Abstract: This study deals with blood viscosity factors not usually employed in the biorheological characterization of disease or as prognostic indices, The apparent viscosity of artificial red/white and white thrombi and aggregation of red cells, as defined by the erythrocyte sedimentation rates corrected for plasma viscosity and adjusted to haematocrit of 30 per cent, arc elevated in cardiovascular diseases, such as myocardial infarction and renal failure, and in malignant melanoma. The two new potential diagnostic or prognostic parameters studied are: (a) influence of fibrinogen level on the apparent viscosity of artificial thrombi and on the aggregation of red cells; and (b) …influence of ABO blood groups on the correlations obtained for the functions described under (a). It is shown that the effect of fibrinogen varies greatly depending not only on the type of disease but also on the type of ABO blood group. While in the normal states or in artificial systems the levels of fibrinogen arc correlated with the increases in these rheological parameters, there is no correlation in vascular disorders. In all the vascular and malignant disorders there were very significant (P < 0.001) differences between A and O, A and B, and Band O blood groups in the effects of fibrinogen level on these rheological functions. Show more

DOI: 10.3233/BIR-1973-10412

Citation: Biorheology, vol. 10, no. 4, pp. 585-594, 1973

Authors: Lahav, J. | Eliezer, N. | Silberberg, A.

Article Type: Research Article

Abstract: Vessels in the microcirculation have been compared to channels in a gel. In this study a method has been developed whereby a geometrically well defined section of a flow system was composed of a cylindrical gel mantic of outer radius R G , surrounding a cylindrical channel of radius R . Both the channel and the mantle were of length L and were contained in a rigid transparent support of inner radius R G . Hence R G and L were fixed (R G = 1.3 or 4.5 mm; L = …40 mm) and the radius R ≃ 0.14 mm could be measured by mounting the whole system on the stage of a microscope fitted with an eye-piece micrometer. The gel was crosslinked polyacrylamide swollen with water. Water also served as the flow medium. It was found that R increased with absolute pressure applied statically to the system under no flow conditions. In flow the channel tended to expand upstream and contract down stream. Flow rate Q through the system and pressure drop ΔP were measured and the radius of the channel was monitored as a function of distance x along its length. At low pressure gradients now rates Q agreed with the theoretically predicted flow rates Q o but dropped below Q o at higher pressure gradients even though allowance was made for changes in R in calculating Q o and flow was shown to be laminar. The extent of the deviation decreased with gel rigidity G ′ and increased with thickness of the gel wall R G − R . The results expressed as Q /Q o could be correlated when plotted as a function of α = ( R G / 2 L G ′ ) Δ P , and corresponded approximately to the function Q / Q o = ( 1 − α ) 4 . The relevance of these results for the microcirculation is discussed. Show more

DOI: 10.3233/BIR-1973-10413

Citation: Biorheology, vol. 10, no. 4, pp. 595-604, 1973

Authors: Stoltz, J.F. | Raffoux, C. | Genetet, B. | Vigneron, C. | Streiff, F. | Larcan, A.

Article Type: Research Article

DOI: 10.3233/BIR-1973-10414

Citation: Biorheology, vol. 10, no. 4, pp. 605-609, 1973

Authors: Gross, J.F.

Article Type: Other

DOI: 10.3233/BIR-1973-10415

Citation: Biorheology, vol. 10, no. 4, pp. 611-612, 1973

Authors: Gaehtgens, Peter | Meiselman, Herbert J.

Article Type: News

DOI: 10.3233/BIR-1973-10416

Citation: Biorheology, vol. 10, no. 4, pp. 613-616, 1973

Authors: Silberberg, A.

Article Type: Announcement

DOI: 10.3233/BIR-1973-10417

Citation: Biorheology, vol. 10, no. 4, pp. 617-618, 1973

Article Type: Correction

DOI: 10.3233/BIR-1973-10418

Citation: Biorheology, vol. 10, no. 4, pp. 619-619, 1973