Clinical Hemorheology and Microcirculation - Volume 16, issue 1

Authors: Stoltz, J.-F.

Article Type: Other

DOI: 10.3233/CH-1996-16101

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 1-2, 1996

Authors: Ehrly, Albrecht. M.

Article Type: Other

DOI: 10.3233/CH-1996-16102

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 3-9, 1996

Authors: Hardeman, Max R.

Article Type: Other

DOI: 10.3233/CH-1996-16103

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 11-15, 1996

Authors: Forconi, Sandro | Guerrini, Maurizio

Article Type: Other

DOI: 10.3233/CH-1996-16104

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 17-22, 1996

Authors: Rampling, M.W.

Article Type: Other

DOI: 10.3233/CH-1996-16105

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 23-25, 1996

Authors: Boisseau, Michel R.

Article Type: Other

DOI: 10.3233/CH-1996-16106

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 27-30, 1996

Authors: Vaya, Amparo

Article Type: Other

DOI: 10.3233/CH-1996-16107

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 31-33, 1996

Authors: Lavalle, Ph. | Senger, B. | Schaaf, P. | Voegel, J.-C. | Stoltz, I.-F.

Article Type: Research Article

Abstract: Red blood cells (RBC), previously fixed with glutaraldehyde, adhere to glass slides coated with fibrinogen. The RBC solution is injected in a diffusion cell where the RBC's settle on the horizontal glass surface, which is observed with an inverted optical microscope. This experiment is repeated for a series of RBC concentrations in the solution. The relative surface covered by the RBC's, as well as the variance of this surface coverage, is obtained for each concentration by means of image processing. In order to model the process, the RBC's are approximated by disks or spheres. A simulation code was developed on …the basis of the “Random Sequential Adsorption” (RSA) model. Usually, no overlap is allowed, and the particles, once adsorbed, stay permanently fixed in place. Here, the model is extended to account for possible overlap between the RBC's. The surface covered, estimated by simulation, as a function of the number of particles deposited on the surface, shows a clear deviation from a linear relation if overlaps are taken into account; this trend is supported by the experimental data. In the same way, the coverage fluctuation is best reproduced if overlaps are allowed. On the other hand, somewhat surprisingly, a model taking into account both the random diffusion of the RBC's and the gravitational force they experience, but assuming no overlaps, describes also quite reasonably the experimental coverage fluctuation. Show more

Keywords: eryIhrocytes, adhesion, coverage, fluctuation, experiments, computer simulations

DOI: 10.3233/CH-1996-16108

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 35-42, 1996

Authors: Riha, P. | Stoltz, J.F.

Article Type: Research Article

Abstract: One of the mechanical factors affecting significantly RBC aggregation, and consequently blood flow, is the oscillatory character of flow. This fact follows from the measurement of RBC aggregation and rheological behaviour of blood in both steady shearing flow and steady shearing flow with superposed oscillations. At the comparable flow conditions, RBC are more disaggregated in oscillatory flow due to oscillations then in steady shearing flow. Consequently, the viscous character of blood rheological behaviour in oscillatory flow does not change so significantly with decreasing intensity of flow as shear viscosity and the effect of elasticity on blood flow is nearly eliminated. …It suggests that the significance of various changes in RBC aggregability of different origin may be substantially suppressed in oscillatory flow of blood in spite of the decisive effect of the aggregability changes on blood shear viscosity and steady shearing flow. Show more

Keywords: Kinetics ofRBC aggregation, Blood rheology in oscillatory flow

DOI: 10.3233/CH-1996-16109

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 43-48, 1996

Authors: Baskurt, Oguz K.

Article Type: Research Article

Abstract: Activated leukocytes generate oxygen free radicals and cause injury in a variety of surrounding cells. Red blood cells (RBC) are among the most susceptible cells to this injury. Deformability, lipid peroxidation and membrane proteins were investigated in RBC after incubation with activated granulocytes (2 hours, at 37°C), obtained from guinea pigs with experimental sepsis. A second group of experiments was conducted with non-activated granulocytes isolated from blood of healthy guinea pigs. RBC transit time through 5 μm pores measured by a cell transit analyzer was 3.25 ± 0.12 msec and 2.86± 0.02 msec in the suspensions containing activated and non-activated …granulocytes, respectively (p<0.05). Addition of superoxide dismutase (SOD) (20 Ilg/ml) and catalase (40 μg/ml) inhibited the effect of activated granulocytes on RBC deformability. Lipid peroxidation was also increased under the influence of activated granulocytes (31.50 ± 3.36 nmol/grHb versus 20.02 ± 2.97 nmol/grHb); SOD failed to prevent this increment, while catalase was found to be effective. A widening of Band 1 (spectrin) was observed in SDS-PAGE electrophoresis of membrane proteins of RBC incubated with activated granulocytes, indicating spectrin-hemoglobin crosslinking. This alteration was prevented by both SOD and catalase, as in the case of transit time. The superoxide radical seems to be responsible for the membrane protein and mechanical alterations, while lipid peroxidation was induced by a different oxidative mechanism. Show more

Keywords: Red blood cell deformability, leukocyte activation, oxidant stress

DOI: 10.3233/CH-1996-16110

Citation: Clinical Hemorheology and Microcirculation, vol. 16, no. 1, pp. 49-56, 1996