Clinical Hemorheology and Microcirculation - Volume 20, issue 2

Authors: Karabetsos, E. | Papaodysseus, C. | Koutsouris, D.

Article Type: Research Article

Abstract: In order to study the important phenomenon of aggregation of red blood cell in vitro, an original ultrasound Doppler in vitro technique has been designed and developed in our laboratory. In the experiments held with this new technique, erythrocyte aggregation was examined by adding dextrans of different molecular weights and concentrations for a wide range of hematocrit values. Consequently, a large data base of backscattered ultrasound Doppler signals is created. In these signals, various pattern recognition methods have been applied, mainly morphological and statistical ones. It results from the employed analysis that the envelope, energy and area characteristics of the …obtained backscattered signals are quite good indicators of the degree of RBCs aggregation. In this way, we have been able to: (a) Establish a quantitative relation between the presence of various dextrans and the degree of aggregation. (b) Determine the distribution of the size of the formed aggregates in the various experimental solutions. (c) Obtain a most accurate relation between ultrasound backscattering and actual size of the corresponding observed aggregates. Show more

Keywords: Erythrocyte aggregation, PW Doppler ultrasound, in vitro, pattern recognition

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 63-75, 1999

Authors: Sargento, L. | Zabala, L. | Saldanha, C. | Souza‐Ramalho, P. | Martins‐Silva, J.

Article Type: Research Article

Abstract: Sodium fluorescein angiography is a widely used technology in ophthalmology, which allows us to visualise the chorioretinal microcirculation. Previous reports showed a prolongation of the retinal circulation time along with erythrocyte hyperaggregation and a decrease of erythrocyte acetylcholinesterase activity and a possible interference with the erythrocyte’s membrane fluidity. The aim of the present work is to investigate the influence of sodium fluorescein on the hemorheological profile of a group of 23 non‐insulin dependent diabetes mellitus (NIDDM) patients undergoing routine retinal angiography. Thirty minutes after the endovenous administration of the fluorescein there was: (I) an increase of whole …blood viscosity (p=0.015 ), erythrocyte elongation index (EEI, p<0.05 ), whole blood pH (p<0.001 ), methemoglobin (p<0.001 ) and carboxyhemoglobin (p<0.001 ) concentrations; (II) no variation of plasma osmolality and erythrocyte aggregation index (EAI); (III) a decrease of the erythrocyte acetylcholinesterase activity, p<001 ; (IV) no variation in membrane lipid fluidity, although 1,6‐diphenyl‐1,3,5‐hexatriene (DPH) correlated directly with the EEI, while 1,4‐trimethyl‐phenyl‐1,3,5‐hexatriene (TMA‐DPH) and EAI correlated inversely, suggesting that the decreasing EEI (lower erythrocyte deformablity) might be associated with an increased rigidity of the external polar region and fluidification of the hydrophobic region of the erythrocyte membrane, with an increasing EAI. In conclusion, the endovenous administration of sodium fluorescein in NIDDM patients during the retinal angiography procedure interferes with the erythrocyte membrane and possibly with the microcirculatory blood flow. Show more

Keywords: Non‐insulin dependent diabetes mellitus, sodium fluorescein, erythrocyte aggregation, erythrocyte deformability, whole blood viscosity, carboxyhemoglobin, methemoglobin, erythrocyte membrane fluidity

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 77-84, 1999

Authors: Caimi, G. | Messina, L. | Alfano, R. | Canino, B. | Fabbiano, A. | Cammarata, A.M. | Lo Presti, R.

Article Type: Research Article

Abstract: In a group of subjects (n = 35 ) with nonvalvular atrial fibrillation (AF) subdivided according to the presence (n = 16 ) or absence (n = 19 ) of left atrial spontaneous echocontrast (SEC), demonstrated using transthoracic and transesophageal echocardiography, we evaluated the principal haemorheological determinants: whole‐blood viscosity, plasma and serum viscosity, haematocrit, whole‐blood filtration (VBC) and mean erythrocyte aggregation (MEA). From the obtained data it was evident that in subjects with nonvalvular AF there was an impairment of the haemorheological profile that seemed more evident in AF subjects with SEC, although no significant haemorheological difference …was present between AF subjects with and without SEC. These findings need to be underlined considering that this clinical condition is associated to a major thromboembolic risk. Show more

Keywords: Atrial fibrillation, atrial echocontrast, haemorheological determinants

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 85-90, 1999

Authors: Vayá, Amparo | Martínez, Marcial | Ballesta, Antonio | Martí, Roberto | Ortuño, Carmen | Aznar, Justo

Article Type: Research Article

Abstract: In order to ascertain whether young asymptomatic patients with heterozygous familial hypercholesterolemia (FH) but without clinical signs of atherosclerosis have increased plasma thrombomodulin (TM) levels expressing early endothelial damage, we determined TM in 23 heterozygous FH subjects (aged 28–44 years, x : 32 \pm 6) and in a well matched control group (CG). In addition, carotid Doppler ultrasonography was done in all the patients and controls in order to assess the state of the vascular tree. Results show a tendency for FH subjects to have higher TM values than the CG (37.8 \pm 14.2 ng/ml …vs. 30.1 \pm 11.2 ng/ml), although the differences are not statistically significant. When taken toghether the results of TM and carotid ultrasound, the sensitivity and specificity of the former were only 66% and 80%, respectively. The fact that only 66% of the FH patients with atherosclerotic injury had high TM values eliminates the possibility of using this as an early marker of atherosclerosis in FH individuals. Show more

Keywords: Thrombomodulin, familial hypercholesterolemia, atherosclerosis

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 91-96, 1999

Authors: Korol, Ana | Rasia, Rodolfo J.

Article Type: Research Article

Abstract: A numerical method is proposed to evaluate the fractal correlation coefficient on viscoelastic properties of mammalian erythrocyte membranes from the diffractometric data obtained with the erythrodeformeter . The numerical method is formulated on the basis of the fractal approximation for ordinary Brownian motion (OBM) and fractionary Brownian motion (FBM) . Photometric readings performed on the elliptical diffraction pattern, generated by the shear elongated cells and photometrically recorded curves of creep and recovery of cells, are used in the calculations of self‐affine Brownian correlation coefficient, averaged over several millions of cells. The time dependence of the correlation coefficient from …different hematological disorders and also from healthy donors was calculated, and significative differences were found between both results. Diffractometric data belonging to healthy donors behaves as white noise, while data series from different disease were found to be chaotic. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 97-103, 1999

Authors: Di Massimo, C. | Taglieri, G. | Penco, M. | Tozzi‐Ciancarelli, M.G.

Article Type: Research Article

Abstract: Ten healthy nonsmoking old men (age 52–70 years, OM) and ten healthy nonsmoking young men (age 20–30 years, YM) were submitted to an exercise test on a bicycle ergometer to examine the combined influence of aging and exercise‐induced stress on platelet function. Data were analyzed by two‐way ANOVA test to determine the statistical significance of differences between baseline, after exercise and after recovery values, and by Mann–Whitney test to compare differences between young and old groups. Our results show in OM at rest an increased platelet aggregability induced by the higher values of intraplatelet basal free calcium (143.3 \pm …4.8 vs. 121.5 \pm 6.0 nM, p<0.05 ) and a statistically significant increase of plasma oxidative by‐products evaluated as thiobarbituric acid‐reactive substances (TBA‐RS: 5.9 \pm 0.7 vs. 1.5 \pm 0.1 \mu mol/l, p<0.05 ). Further, significant modifications of calcium and TBA‐RS levels were found in both groups because of exercise‐induced stress. The positive relationships between calcium amount and plasma values of TBA‐RS in OM before (r={} 0.728, p={} 0.017) and after (r={} 0.772, p={} 0.009) physical test and in YM only at the end of exercise (r={} 0.853, p={} 0.002), underline that oxidative stress may modulate platelet function by influencing calcium homeostasis and platelet membrane permeability. Show more

Keywords: Aging, platelet function, exercise, oxidative stress

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 105-110, 1999

Authors: Saldanha, C. | Sargento, L. | Monteiro, J. | Perdigão, C. | Ribeiro, C. | Martins‐Silva, J.

Article Type: Research Article

Abstract: Erythrocytes have to constantly adapt themselves to the varying circulatory system shear stress forces and capillaries diameter. Membrane lipid and protein content have an important role in determining the erythrocyte shape and are main determinants of the membrane solid and fluid behaviour which enables the erythrocyte to respond to the outer environment modifications. Membrane fluidity is an inverse index of membrane microviscosity. The aim of the present work is to evaluate prospectively in three periods of time (discharge, after 6 months and one year later) in survivors of an acute myocardial infarction (AMI) the erythrocyte membrane fluidity (outer and inner …bilayer) and establish a relation with the cardiovascular events or need of coronary revascularization during a two year clinical follow up. Sixty survivors of acute myocardial infarction were recruited during 1994–96 and were prospectively studied in three periods (discharge, 6 months and after one year), and were compared with a control group (n=36 ). Membrane lipid fluidity was determined by means of fluorescence polarisation with two probes: 1,6‐diphenyl‐1,2,5‐hexatriene (DPH) and 1,4‐trimethylamine 6‐phenyl hexa‐1,3,5‐triene (TMA‐DPH), for the characterisation of the hydrophobic and external polar region, respectively. The hydrophobic region was more rigidified (p<0.01 ) in the erythrocytes from AMI patients, in relation to the control group. During the time of the study there was a progressive erythrocyte membrane rigidification (DPH p<0.001 ; TMA‐DPH p<0.001 ). We found no relation between erythrocyte membrane fluidity and the coronary risk factors, cardiovascular events or the need of coronary revascularization during the clinical follow‐up. In conclusion, after the myocardial infarction erythrocyte membrane of AMI survivors becomes more rigid with time, which could contribute to the decreased erythrocyte deformability and the increased blood viscosity previously described in this group of patients. Show more

Keywords: Erythrocyte membrane fluidity, acute myocardial infarction, prospective study

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 111-116, 1999

Authors: Aïssa Benhaddad, A. | Bouix, D. | Khaled, S. | Micallef, J.P. | Mercier, J. | Bringer, J. | Brun, J.F.

Article Type: Research Article

Abstract: A standardized questionnaire has been proposed by the French consensus group on overtraining of the Société Française de Médecine du Sport (SFMS) and allows the calculation of a ‘score’ that may help to quantify the early clinical symptoms of the overtraining syndrome in sportsmen submitted to a heavy training program. We investigated a possible relationship between this score and blood rheology in 36 male elite sportsmen (national level in football, volleyball and karate; age: 17–33 yr) who underwent a standardized check‐up including biological measurements and an exercise‐test. The overtraining score ranged between 0 and 21 items and was correlated with …blood viscosity (r={} 0.413, p<{} 0.02). This correlation was explained by a correlation of this score with plasma viscosity (r={} 0.512, p<{} 0.01) and hematocrit (r={} 0.387, p<{} 0.05). When subjects with a high score (> 6) were compared to subjects with a lower score they appeared to have a higher blood viscosity at native (but not corrected) hematocrit (3.18 \pm 0.01 vs. 2.89 \pm 0.05 mPa.s, p<{} 0.02), explained by higher values in both plasma viscosity (1.39 \pm 0.02 vs. 1.31 \pm 0.02 mPa.s, p<{} 0.01) and hematocrit (42.8 \pm 0.45 vs. 41.1 \pm 0.44, p<{} 0.05). By contrast, there was no difference in RBC deformability and aggregation. Overtrained subjects have also lower levels of zinc (0.72 \pm 0.024 vs. 0.84 \pm 0.023 mg/l, p<{} 0.01), ferritin (55.1 \pm 7.3 vs. 92.3 \pm 9.4 ng/ml), and IGF‐binding protein 3 (3.4 \pm 0.22 vs. 4.52 \pm 0.4 ng/ml). Neither zinc nor ferritin status were likely to explain the rheologic alterations since disturbances in zinc or iron are rather associated with abnormalities in erythrocyte deformability or aggregability. Therefore, the early signs of overtraining in elite sportsmen are associated with a hemorheologic pattern that suggests some degree of reversal of the ‘autohemodilution’ associated with fitness in athletes. Show more

Keywords: Blood viscosity, plasma viscosity, exercise, overtraining, hemorheology, IGFBP3, serum zinc, ferritin

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 117-125, 1999

Authors: Stoltz, J.F. | Muller, S. | Wang, X. | Dumas, D. | Boisseau, M. | Legrand, S. | Labrador, V.

Article Type: Research Article

Abstract: The vascular endothelium is a biologically active monolayer of cells provided an interface between blood and tissues. Vascular endothelial cells (ECs) have two functional states, which are allowed by their different properties: (i) vaso regulating properties: ECs releases vasomotor components, as endothelin (vaso constriction), prostacyclin and nitrite oxide (vaso dilatation); (ii) antithrombotic and hemostatic properties; and (iii) anti‐adhesion properties. The endothelium is normally anti‐thrombotic and anti‐adhesive to ensure blood fluidity. During many cardio‐vascular diseases, these properties may be reversed. Thus, the ECs have a determinant role in hemodynamic control through these various metabolic activities. Otherwise, many studies have demonstrated that …local blood flow conditions have a crucial role on the EC properties (mechanotransduction concept). The knowledge of the properties of ECs and the control of the phenomena which define their functions is a key element in the cardiovascular diseases understanding. Show more

Keywords: Endothelial cells, cell adhesion, adhesion molecules, hemorheology, mechanotransduction

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 127-139, 1999

Authors: Foresto, Patricia | D’Arrigo, Mabel | Racca, Liliana | Valverde, Juana

Article Type: Short Communication

Citation: Clinical Hemorheology and Microcirculation, vol. 20, no. 2, pp. 141-143, 1999