Clinical Hemorheology and Microcirculation - Volume 11, issue 5

Authors: Bravo, M.L. | Escolar, G. | White, J.G.

Article Type: Research Article

Abstract: There is in vivo evidence that dextrans have antiplatelet effect. We have performed a series of experiments to elucidate a possible hemorheological action through which dextrans might alter platelet function. A perfusion system allowing morphometric evaluation of platelet interaction with subendothelial structures was used for this purpose. Perfusion experiments were performed in the presence of dextran 40 or 70 (10% v:v) or with blood reconstituted with dextran-incubated red blood cells. Experiments in which blood or red blood cells were treated with the same proportion of 4% human serum albumin (HSA) were used as a control. Changes in the mechanical properties …of red blood cells were morphologically assessed with a micropipette aspiration technique. None of the dextrans used modified the mechanical properties of red blood cells. However, both dextran 40 (D40) and dextran 70 (D70) increased the intensity of the interaction of platelets with subendothelial structures when added to whole blood. Our experiments suggest that when added in vitro dextrans do not alter the hemorheological mechanisms of platelet function. Show more

Keywords: Dextran, hemorheology, red blood cells, platelet function

DOI: 10.3233/CH-1991-11511

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 339-349, 1991

Authors: Nagakawa, Yuzo | Akedo, Yoko | Kaku, Shiho | Orimo, Hajime

Article Type: Research Article

Abstract: The effects of idebenone (6-(10-hydroxydecyl)-2,3-dimethoxy-5-methyl-1,4-benzoquinone) on hemorheologic variables were evaluated in 7 geriatric patients with cerebral infarction, 3 men and 4 women (ages 61–83, mean age 70.7 years). Idebenone was given orally at a dose of 30–60mg three times daily after meals for 12 weeks. The hemorheologic variables were determined twice prior to the administration and at 8 and 12 weeks after the administration. Hemorheologic measurements included erythrocyte deformability was determined according to the method based on the examination of passing erythrocytes through a filter containing pores smaller than the undeformed cells. Erythrocyte aggregation was measured by the method based …on the increase of the light transmission through whole blood that occurs when individual cells aggregate into rouleaux or rouleaux-rouleaux complexes. Erythrocyte deformability was increased and erythrocyte aggregation measured at a high shear rate and a low shear rate, plasma viscosity and collagen-induced platelet aggregation were also decreased after the administration. Thus the improvement of hemorheologic variables in cerebral infarction may prevent from disturbing blood flow and may contribute to prevention of formation and progression of thrombosis and atherosclerosis in geriatric patients with cerebral infarction. Show more

Keywords: idebenone, erythrocyte deformability, erythrocyte aggregation, plasma viscosity, platelet aggregation

DOI: 10.3233/CH-1991-11512

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 351-359, 1991

Authors: Laghi Pasini, F. | Pasqui, A.L. | Pieragalli, D. | Acciavatti, A. | Saletti, M. | Guideri, F. | Galigani, C. | Di Perri, T.

Article Type: Research Article

Abstract: It has been demonstrated that iron and iron compounds facilitate hydroxyl radical generation from activated oxygen species. Free haemoglobin (Hb), like other iron-rich substances, might also mediate hydroxyl radical production and induce lipid peroxidation and cell damage. On the basis of the hypothesis that Hb may influence circulating blood cells, namely red cells, studies have been carried out on the effect of Hb on rheological properties of whole blood. Hb is capable of significantly influencing whole blood filterability and, to a lesser extent, whole blood viscosity. The addition of Fe2+ has a potentiating effect; superoxide dismutase and …thiourea which are respectively selective inhibitors of superoxide anion and hydroxyl radicals are able to antagonize the Hb-induced rheological impairment. From these observations, the hypothesis may suggest that Hb negatively influences some rheological properties of whole blood by producing oxygen free radicals. Hb released in vivo at the site of arterial stenosis and of atherosclerotic plaque rupture may induce a rheological impairment and, so doing, play a role in microcirculatory derangement. Show more

Keywords: whole blood viscosity and filterability, haemoglobin, oxygen free radical

DOI: 10.3233/CH-1991-11513

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 361-367, 1991

Authors: Braide, M. | Nannmark, U. | Bagge, U.

Article Type: Research Article

Abstract: Bolus infusion of human leukocytes (Polys and/or Monos) during continuous, constant pressure filtration of 5 μm pore (Nuclepore® ) filters was performed in order to calculate cell passage time distributions. The ratio cell to pore number was kept small (about 0.4) to prevent clogging of the filters and to simplify the analyses of the flow recordings that were made continuously with an ultrasonic transit time flow probe. In a first step the flow curves were simply inverted to show the changes in resistance during and after cell filtration. The resistance change in the filters due to the passage of …the leukocyte bolus was similar, both in shape and magnitude, to that seen earlier in isolated organs perfused with a leukocyte bolus. Thus, there was an initial peak in the resistance followed by a slow decline towards a plateau value 5–20% above the baseline. In addition, the results showed that permanent plugging of the filters was inversely related to the driving pressure (25, 50 or 100 mm H2 O), which also correlates well with the results from organ perfusion experiments. The percentage of cells that became permanently trapped in the pores differed between Polys and Monos only at the lowest pressure (35% Monos and 25% Polys). The dynamics of the bolus' approach to and contact with the filter was investigated using glutaraldehyde fixated (rigid) Polys, and then used to de-convolute the flow recordings from the normal cells in order to obtain their passage time distributions. In these analyses, it appeared that the normal leukocytes could be divided into a number of sub-populations with passage times ranging from 0 to infinity. When pressure was changed there was a shift of cells between these sub-populations with the sub-population with infinite passage time being greatest at the lowest pressure. This finding indicates that the importance of the viscous element of the leukocytes, which has been regarded to be the most significant determinator of leukocyte rheology, must be re-evaluated. The present results suggest that cell properties such as adhesiveness and elasticity influence leukocyte rheology to a greater extent than has hitherto been recognized. Show more

Keywords: Leukocyte filtration, passage time distribution, leukocyte rheology

DOI: 10.3233/CH-1991-11514

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 369-382, 1991

Authors: Weiss, Thomas | Ruef, Peter | Linderkamp, Otwin

Article Type: Research Article

Abstract: Micropipettes with internal diameters of 1 to 5 μm are frequently used for manipulation of erythrocytes and leukocytes. A modified method for the production of narrow micropipettes with flat tips is described. A stainless steel rod with a cylindrical bore hole is filled with low-melting point solder glass, which is rapidly melted by a high electrical current. The tip of a micropipette of desired diameter is moved into the softened glass, the electrical current is interrupted and the glass is chilled. When the pipette is removed it usually breaks off with a flat tip.

Keywords: Erythrocytes, hemorheology, leukocytes, micropipette

DOI: 10.3233/CH-1991-11515

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 383-386, 1991

Authors: Schpitz-Droz, R. | Bucherer, C. | Ladjouzi, J. | Lacombe, C. | Lelievre, J. C.

Article Type: Research Article

Abstract: A set of experimental data was previously obtained from blood of healthy controls and insulin-treated diabetics clinically divided into three different groups: diabetics without retinopathy, diabetics with minimal retinopathy and diabetics with severe retinopathy (1). Results of the multivariate analysis of both biological and rheological data suggest the presence in diabetic plasma of two kinds of fibrinogen in contrast with normal plasma.

Keywords: multivariate analysis, diabetic plasma, fibrinogen

DOI: 10.3233/CH-1991-11516

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 387-396, 1991

Authors: Puniyani, R.R. | Sonar, Sameer

Article Type: Research Article

Abstract: Hemorheological profile of a group of menopausal female subjects have been studied. Parameters such as whole blood viscosity, plasma viscosity, hematocrit, red cell rigidity and biochemical values such as plasma fibrinogen, proteins are evaluated. Females in premenopausal phase are taken as controls. Menopausal women showed significantly high whole blood viscosity, plasma viscosity and red cell rigidity. There was no significant rise in hematocrit and plasma fibrinogen. The results suggest that the menopausal phase plays important role in altering the rheology of blood. This change in rheology can be a potential risk factor in the development of ischaemic heart diseases.

Keywords: Menopause, Hemorheology, Ischaemic heart disease

DOI: 10.3233/CH-1991-11517

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 397-403, 1991

Authors: Lapolla, A. | Calabrò, A. | Gerhardinger, C. | Dal Frà, M.G. | Franchin, A. | Fedele, D. | Crepaldi, G.

Article Type: Research Article

Abstract: Glycated erythrocyte membrane proteins and some metabolic parameters (plasma glucose profile, glycosuria, glycated haemoglobin, glycated serum proteins, cholesterol, triglycerides) were evaluated in 35 subjects, that is, 20 insulin dependent diabetics and 15 controls, matched for sex and age. Whole blood and washed erythrocyte filtrability, whole blood, - washed erythrocyte - and plasma viscosity were evaluated in all subjects. Glycated erythrocyte membrane proteins were significantly higher in diabetics with respect to controls (10.6±0.4 vs 4.3±0.2 nmlHMF/mg prot;p<0.001) and correlated with all the metabolic parameters considered. Significantly lower values of whole blood and washed erythrocyte filtrability (2.0±0.13 vs 2.4±0.13 ml/min,p<0.01; and 5.85±0.11 …vs 6.58±0.18 ml/min,p<0.001) and significantly higher values of washed erythrocyte viscosity were found in diabetics with respect to controls (2.20±0.05 vs 2.03±0.04 cP,p<0.02). Glycated erythrocyte membrane proteins were inversely related to washed erythrocyte filtrability in diabetic patients. A demonstrable effect on erythrocyte filtrability is caused by the degree of glycation on erythrocyte membrane proteins of non diabetic subjects incubated with glucose. A very close relationship was found between the two alterations (r=0.82,p<0.001). These results suggest that the glycation of erythrocyte membrane proteins could be an important factor determining some haemorheological alterations in diabetics. Show more

Keywords: Diabetes Mellitus, glycated erythrocyte membrane proteins, metabolic control, haemorheological parameters, microangiopathy

DOI: 10.3233/CH-1991-11518

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 405-415, 1991

Authors: Phat, Darith | Ley, Klaus | Arfors, Karl-E. | Intaglietta, Marcos

Article Type: Research Article

Abstract: Detachment of adherent human PMN from cultured endothelial cells (human umbilical vein, HUVEC) and from immobilized albumin (bovine serum albumin, BSA) was investigated as a function of shear stress. Non-activated PMN did not adhere to either of the substrates (<2%). 20 min after activation with PMA (phorbol myristate acetate, 10 nM), 48 ± 5% (mean ± SEM, n=15) of the total number of PMN added had adhered to albumin, and 18 ± 4% (n=9) to HUVEC. The dishes with pre-adhered PMN were subjected to shear stress in the range occurring in venules in vivo, using a rotating plate-and-cone (cone angle …2.5°) apparatus made of transparent plastic to allow observation of the cells during the assay. On HUVEC, the majority of adhered PMN (66 ± 3%, n=9) was removed by a shear stress of 0.12 Pa (1.2 dyn/cm2 ), while the same shear stress removed only 15 ± 5% (n=9) of the PMN adhered to BSA. Further increase of shear stress to 2.3 Pa (23 dyn/cm2 ) removed 39 ± 4% (n=14) of the PMN adhered to BSA. Using spherical and semispherical approximations for the shape of the adhered PMN, the adhesive forces between PMA-activated PMN and HUVEC were calculated to be on the order of 0.05 nN per PMN, while most PMN on BSA adhered with a force of more than 4 nN per PMN. The force needed to detach PMN from HUVEC is more than one order of magnitude lower than value reported for PMN adhesion to venular endothelium in vivo. The present results suggest that the endothelium may playa regulatory role in PMN adhesion and limit the attachment force to allow emigration. Show more

Keywords: PMN-endothelium adhesion, cell culture, microcirculation hemodynamics

DOI: 10.3233/CH-1991-11519

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 417-428, 1991

Authors: Ernst, E. | Daburger, L. | Saradeth, T.

Article Type: Research Article

Abstract: The aim of the study is to define the kinetics of hemorheological changes during and after a standardized bicycle ergometry lasting for 3 hours. Hematocrit, plasma and blood viscosity, red cell aggregation and deformability are measured in 15 volunteers hourly during exercise and followed for 21 hours thereafter. During exercise there is a marked viscidation of the blood which is caused by hemoconcentration and partial loss of red cell deformability. Subsequently blood cell rheology factors normalize. Three hours after exercise there is a marked fall of hematocrit and plasma viscosity. Native blood viscosity declines significantly below baseline values 5 hours …after discontinuation of exercise and is still reduced 24 hours after the start of the experiment. The results suggest that the well known exercise-induced hemoconcentration is reversed after discontinuation of exercise when a marked “autohemodilution” takes place. Show more

Keywords: hemorheology, exercise, sports anemia, fluid shifts, sports physiology

DOI: 10.3233/CH-1991-11520

Citation: Clinical Hemorheology and Microcirculation, vol. 11, no. 5, pp. 429-439, 1991