Biorheology - Volume 26, issue 2

Authors: Copley, Alfred L.

Article Type: Research Article

Abstract: Perihemorheology concerns the rheology of fluids and structures in the perivascular spaces. Furthermore, the term refers to the exchanges of rheological processes between the vessel-blood organ and its surrounding tissues, as well as in reverse. In 1960, the vessel wall and the circulating blood were considered by the author as an entity which in 1981 he postulated as an organ, named the ‘vessel-blood organ’, penetrating all other organs. This communication is not a survey but is intended to stimulate biomedical thinking regarding the importance of perihemorheology. The significance of the endoendothelial fibrin(ogenin) lining (EEFL) and fibrin(ogenin) as constituent of the …interendothelial cement and the basement membrane in relation to perihemorheology is stressed. The role of albumin in the exchanges between hemorheology and perihemorheology is discussed. The protein content, as found by Witte, in the perivascular spaces as compared to the blood is emphasized regarding the importance of interrelations between the vessel-blood organ and rheological processes in the perivascular spaces. Recent studies, particularly by Laurent and his group, pertaining to hyaluronan in perivascular spaces and the blood demonstrate also the importance of the interrelationship between hemorheology and perihemorheology. The term ‘blood-brain barrier’, considered no longer to be adequate, is replaced by the term ‘basement membrane-brain barrier’. It is proposed that the basement membrane of the vessel-blood organ penetrating the brain may contain certain constituents, unknown thus far, and may have a different structure from the basement membrane of the vessel-blood organ penetrating organs other than the brain. Show more

Keywords: Albumin, basement membrane, basement membrane-brain barrier, blood-brain barrier, brain-perivascular space barrier, endoendothelial fibrin (ogenin) lining, endothelium, fibrin(ogenin), hemorheology, hyaluronan, interendothelial cement, perihemorheology, perivascular proteins, perivascular spaces, plasma proteins, vessel-blood organ

DOI: 10.3233/BIR-1989-26220

Citation: Biorheology, vol. 26, no. 2, pp. 377-388, 1989

Authors: Nordt, F.J. | Seaman, G.V.F.

Article Type: Research Article

Abstract: Electrokinetic measurements and rheological studies conducted in parallel have previously shown red cell surface charge to play a role in governing aggregative behavior and bulk flow properties of red cell suspensions. For these and other types of model investigations, aldehyde stabilized cells have been widely used. In this communication, the influence of the purity of formaldehyde was investigated. It was found that (a) the direct dissolution of commercially available paraformaldehyde in water or suitably buffered saline results in impure solutions which, if utilized in the fixation of human erythrocytes, produces cells which have significantly different electrophoretic properties from native cells; …(b) the basis for the differences is the presence of metallic impurities in some commercially available paraformaldehyde preparations; (c) the impurities and thus the anomalous electrokinetic properties of the fixed cells may be eliminated by generating formaldehyde gas from paraformaldehyde by heating the latter to 203–210°C; (d) alternatively, the impurities may be eliminated by addition of disodium ethylenediamine tetraacetate dihydrate to fixative solutions prepared directly from paraformaldehyde. Show more

Keywords: rheology, electrophoresis, erythrocyte aggregation, erythrocyte aging, formaldehyde

DOI: 10.3233/BIR-1989-26221

Citation: Biorheology, vol. 26, no. 2, pp. 389-400, 1989

Authors: Fukada, Eiichi | Seaman, Geoffrey V.F. | Liepsch, Dieter | Lee, Martin | Friis-Baastad, Lise

Article Type: Research Article

Abstract: The steady flow viscosity at shear rates 0 to 120 sec−1 and dynamic viscoelasticity at frequencies 0.02 to 0.8 Hz were determined for aqueous suspensions of uniform polystyrene microspheres of 1.0 μ m diameter. Rheological properties of the microsphere suspensions were Newtonian for particle concentrations up to 32%. By introducing dextran and calcium chloride into the particle suspensions, non-Newtonian behavior was produced similar to that observed for human blood. The cooperative effects of dextran and calcium ions promoted aggregation of particles at a concentration as low as 12%. Thus, a suspension of uniform sized spherical polystyrene particles in aqueous …solution of dextran may be made to mimic blood by controlling the surface charge on the polystyrene spheres using addition of calcium ions to the medium. Show more

Keywords: blood modeling, polystyrene micro spheres, latexes, dispersions, dextran, calcium chloride

DOI: 10.3233/BIR-1989-26222

Citation: Biorheology, vol. 26, no. 2, pp. 401-413, 1989

Article Type: Other

DOI: 10.3233/BIR-1989-26223

Citation: Biorheology, vol. 26, no. 2, pp. 415-415, 1989

Article Type: Announcement

DOI: 10.3233/BIR-1989-26224

Citation: Biorheology, vol. 26, no. 2, pp. 417-421, 1989