Clinical Hemorheology and Microcirculation - Volume 30, issue 3-4

Authors: Binzen, E. | Lendlein, A. | Kelch, S. | Rickert, D. | Franke, R.P.

Article Type: Research Article

Abstract: Biomaterial research is expected to forward new materials to be used as, e.g., implant materials or as scaffolds for tissue engineering. It is central for such a scaffold material to create the track on which those cells can inhabitate the scaffold needed to rebuild functional tissue substitutes. For the biointegration of the implant with the native cellular tissue this must be able to grow on the material surface. For the elimination of the degradation products and the adeqaute transport of nutrients/gases within the newly formed tissue the angiogenesis of new blood vessels is thought to play an important role. …In the present study, a new biomaterial, a non‐porous polymeric AB‐network based on oligo (ε‐hydroxycaproat) and oligobutylacrylat, was implanted in animals. Male NMRI mice were implanted subcutaneously for one week to nine weeks. Immediately after the explantation, the probes were examined histologically. Already one week after implantation, there was a strong tissue‐integration of the polymer. Importantly, blood vessels appeared at the polymer surface. At nine weeks after implantation the tissue integration was stronger than after one week and blood vessels were still observed in the periimplant tissue. The mechanism of the early integration of the polymer is not clear. The relationship between the new periimplant vessels and the integration of the polymer has to be studied. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 283-288, 2004

Authors: Turchetti, V. | Boschi, L. | Donati, G. | Borgogni, G. | Coppola, D. | Dragoni, S. | Bellini, M.A. | Sicuro, S. | Mastronuzzi, V.M.A. | Forconi, S.

Article Type: Research Article

Abstract: Hemorheological alterations which can be found in ischaemic vascular diseases are well known and widely studied; less clear is the relationship between these alterations and endothelial function. Our studies showed that modifications in endothelial function caused by physical stress are associated with a worsening in hemorheological parameters mainly in patients affected by ischaemic vascular diseases: major vascular alterations have been found in patients with very high levels of plasma markers endothelial dysfunction. The control of the basal tone of the vessels is given by the complex interaction between vasoconstrictor and vasodilator endothelial factors and when this equilibrium is broken we …have the endothelial dysfunction. From a methodological point of view we can find an endothelial dysfunction index determining the various substances produced by the endothelium, but it is very difficult to have a value which clearly identifies the real state of the endothelial alteration. The function of the NO, which is one of the more powerful endogenous vasodilators and whose synthesis is catalysed by nitric oxide synthase (NOS), can be determined by the ratio between blood concentrations of citrulline and arginine (the co‐product and the precursor of the way of NO synthesis), which represents the level of activity of the enzyme. A very affordable index of the endothelial dysfunction is the asymmetric dimethylarginine (ADMA), a powerful endogenous inhibitor of NOS; in fact several studies demonstrated a strong relationship between ischaemic vascular diseases and high levels of plasma ADMA. Evaluation of these parameters is measured by means of high performance liquid chromatography (HPLC): this technique provides very affordable results and allows to obtain evaluations of substances in very small concentrations, like ADMA. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 289-295, 2004

Authors: Le Dévéhat, C. | Vimeux, M. | Khodabandehlou, T.

Article Type: Research Article

Abstract: Blood rheology is now receiving increasing attention as an important potential contributory factor to diabetic angiopathy. This study was designed to provide evidence for and against early hemorheological abnormalities in diabetes mellitus (DM). For this purpose, blood viscosity, RBC aggregation, hematocrit, and plasma protein's levels of both fibrinogen and albumin were measured in 86 uncomplicated patients with DM (45 type 1 and 41 type 2). Patients with HbA1c < 7.5% were considered as having good glycemic control (GGC), while those with HbA1c > 8.5% as having poor glycemic control (PGC). Patients with type 1 DM showed normal blood viscosity at …both shear rates high and low, while native hematocrit, fibrinogen, and RBC aggregation were significantly elevated and albumin significantly reduced when compared with healthy volunteers. Patients with type 2 DM showed more marked impairments associated with an increased low shear rate blood viscosity, when compared with patients with type 1 DM. Comparison between two subgroups of patients, both of which with type 1 DM and of similar disease duration of <5 yrs, with GGC or PGC showed that impaired blood rheology does depend on the quality of glycemic control. Differences were attenuated after a disease duration of >15 yrs. These findings suggest that early hemorheological impairments in patients with type 1 DM are dependent upon the glycemic control. In contrast, hemorheological impairments appear to be inevitable after a mean disease duration of 15 yrs even if there is a GGC. Aggravation of hemorheological abnormalities in patients with type 2 DM might depend upon the hemorheological effects of other metabolic abnormalities related to insulin resistance rather than the quality of glycemic control. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 297-300, 2004

Authors: Cicha, I. | Suzuki, Y. | Tateishi, N. | Maeda, N.

Article Type: Research Article

Abstract: Atherogenic diets rich in saturated fat and cholesterol influence the blood viscosity and red blood cell (RBC) aggregability, the parameters associated with increased risk of circulatory disorders. However, little is known about the effect of triglycerides, which are the major dietary lipid form in humans, on blood rheology. Therefore, we studied the effects of postprandial plasma triglyceride levels on human RBC indices, hematological parameters, RBCs aggregation velocity and whole blood viscosity. For this purpose, whole blood was collected 2 hours after high‐fat or low‐fat meal. Proteins, triglycerides and cholesterol levels of plasma were analysed, and RBCs rouleaux formation rate was …measured in 70% autologous plasma using a low‐shear rheoscope. There were no significant differences in hematological parameters, RBC indices, whole blood viscosity, plasma protein and cholesterol content between high‐fat and low‐fat blood samples. However, a significant increase in rouleaux formation rate was observed in samples with high postprandial triglyceride levels, when compared with low‐triglyceride samples. Plasma triglyceride levels correlated significantly with rouleaux formation rate. In conclusion, these results suggest that diet‐dependent alterations of plasma triglyceride levels as well as possible changes in the cell membrane lipid composition lead to RBC hyperaggregability. Show more

Keywords: Triglycerides, blood rheology, RBC aggregation

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 301-305, 2004

Authors: Khodabandehlou, T. | Boisseau, M.R. | Le Dévéhat, C.

Article Type: Research Article

Abstract: During chronic venous insufficiency (CVI), several microvascular functional abnormalities, due to venous hypertension, develop. To look for blood rheological consequences of venous hypertension “VH”, whole blood viscosity and its main determinants were measured in 11 normal controls and 36 patients with CVI exposed to a short‐term experimental VH. Patients were subdivided into 2 groups according to the severity of their disease. Blood was taken from a foot vein before and after VH, which was induced by appling a pneumatic tourniquet to 100 mmHg for 15 minutes. Whole blood viscosity at low and high shear rates, red blood cell (RBC) aggregation, …RBC rigidity, plasma viscosity and proteins as well as red and white blood cell (WBC) counts were recorded. Patients at baseline, i.e., before application of the tourniquet, showed several hemorheological abnormalities such as an increased RBC aggregation, increased low shear rate viscosity, and a significant elevation in plasma fibrinogen level. Patients with more severe CVI had more marked hemorheological changes. The short term VH in patients led to further aggravation of these changes. There were also at baseline lower values, however not significantly, of hematocrit and RBC count, suggesting that hemoconcentration is not a feature of CVI. These same parameters were slightly, however not significantly, increased after VH, indicating a fluid escape into the extravascular space. A significant fall in WBC count was also observed after VH, in keeping with the white cell trapping hypothesis. In conclusion, even a short‐term VH is able to induce several hemorheological impairments, which are probably involved in the failure of the microcirculation and hence the initiation of tissue damage in patients with CVI. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 307-312, 2004

Authors: Di Massimo, C. | Scarpelli, P. | Tozzi‐Ciancarelli, M.G.

Article Type: Research Article

Abstract: In this study, we have attempted to verify whether a single bout of strenuous exercise performed by sedentary healthy individuals may interfere with the mechanisms controlling platelet sensitivity through exercise‐related modifications of plasma oxidant/antioxidant equilibrium. Strenuous exercise resulted in an increased ADP‐ and collagen‐evoked platelet aggregation associated with modified membrane fluidity and ion homeostasis. We also observed an enhanced plasma accumulation of secondary products of lipid peroxidation together with an increased susceptibility of low density lipoprotein (LDL) to in vitro oxidation and a decreased total plasma antioxidant potential. Notably, an acute elevation of nitrite/nitrate (NOx ) amount was detected in …plasma, whilst a decreased NOx content was measured in platelets. Findings of the current study suggest that oxidative stress induced by acute strenuous exertion may interfere with platelet responsiveness by promoting ox‐LDL‐mediated platelet activation and by decreasing platelet‐derived nitric oxide bioactivity. Show more

Keywords: Exercise, oxidative stress, ox‐LDL, nitric oxide, human blood platelets

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 313-316, 2004

Authors: Aydogan, Sami | Yerer, M. Betul | Yapislar, Hande

Article Type: Research Article

Abstract: Erythrocyte deformability is one of the most important charactheristics of erythrocytes for an effective microcirculatory function and is affected from a number of factors, including the oxidative‐damage‐induced by nitric oxide (NO). This study was performed to investigate the effects of in vitro melatonin incubation on the antioxidant status and deformability of erythrocytes in sodium nitroprusside (SNP), a nitric oxide donor, induced oxidative stress. 40 blood samples taken from the adult healthy people were divided into 4 groups randomly and incubated with saline, SNP (1 mM), melatonin (MEL, 1 mM), MEL + SNP and SNP + L‐NAME (5 mM) respectively. Relative …filtration rate (RFR), relative filtration time (RFT) and relative resistance (Rrel) were determined as the indexes of erythrocyte filterability. In addition, malondialdehyde (MDA, as an index of lipid peroxidation) and the antioxidant activities of glutathione peroxidase (GSH‐Px), superoxide dismutase (SOD) and catalase (CAT) were also determined in the red blood cells of all groups revealing the oxidant–antioxidant activity. RFT and the Rrel of the erythrocytes incubated with SNP increased significantly (p<0.05) whereas the RFR of the erythrocytes decreased (p<0.05) in comparison to all groups. This reduction in RFR was prevented with both L‐NAME or MEL incubation. Furthermore, MEL was found to be significantly efficient in preventing the erythrocytes from lipid peroxidation in these groups. In addition, GSH‐Px and SOD activities were elevated with SNP incubation reflecting the oxidative stress in erythrocytes, whereas the CAT activity remained unchanged. Melatonin has no significant effect on the GSH‐Px and CAT activity but, it caused a significant decrease in SOD activity (p<0.05). These results reveal that, melatonin can protect the erythrocytes from impaired deformability in SNP‐induced oxidative stress due to antioxidant effects as revealed by lipid peroxidation and antioxidant enzyme activities. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 317-322, 2004

Authors: Yerer, M. Betul | Aydogan, Sami

Article Type: Research Article

Abstract: Reactive oxygen species avidly reacts with nitric oxide (NO) producing cytotoxic reactive nitrogen species capable of nitrating proteins and damaging other molecules which leads to the reduction of erythrocyte deformability. The aim of this investigation was to assess the importance of α‐tocopherol (Vit‐E) in the total antioxidant status of the erythrocytes in sodium nitroprusside (SNP), a nitric oxide donor, induced oxidative stress and its relation to erythrocyte deformability. Male Swiss Albino rats were used in 4 groups, comprising of 10 animals in each group. The first group was the control, and the other groups were administered SNP (10 mg/kg, i.p.), …Vit‐E (10 mg/kg, i.p.) + SNP, and SNP + L‐NAME (10 mg/kg, i.p.), respectively. Relative filtration rate (RFR), relative filtration time (RFT) and relative resistance (Rrel) were determined as the indexes of erythrocyte deformability. In addition, malondialdehyde (MDA, as an index of lipid peroxidation) and nitric oxide levels and the antioxidant activities of glutathione peroxidase (GSH‐Px), superoxide dismutase (SOD) and catalase (CAT) were also determined in the red blood cells of all groups revealing the oxidant‐antioxidant activity. RFT and the Rrel of the erythrocytes of the SNP‐treated rats increased significantly (p<0.05) whereas the RFR of the erythrocytes decreased (p<0.05) in comparison to all groups reflecting the impaired deformability. This reduction in RFR was prevented with both L‐NAME or Vit‐E incubation. Vit‐E has also reduced the Rrel of the erythrocyte which reveals that it has improved the erythrocyte deformability. Lipid peroxidation was suppressed by Vit‐E and L‐NAME significantly, where the red blood cell deformability was improved. Furthermore, SOD and CAT activities were significantly stimulated with SNP treatment (p<0.05), where as GSH‐Px remained unchanged. In the contrary, GSH‐Px activity was triggered significantly by Vit‐E administration, whereas the SOD and CAT activities were reduced (p<0.05). As a result, these data reveal that Vit‐E improves the erythrocyte deformability in SNP‐induced oxidative stress by its antioxidant effects on the lipid peroxidation and antioxidant enzyme activities. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 323-329, 2004

Authors: Varlet‐Marie, Emmanuelle | Brun, Jean‐Frederic

Article Type: Research Article

Abstract: Blood lactate increases during exercise. Although this increase was classically interpreted as a “Pasteur‐like effect” resulting from anaerobiosis, it is now clear that it mostly results from a shift in the balance of oxidation of substrates in the muscle, with carbohydrate becoming the predominant fuel. However, we have repeatedly observed that the rise in blood lactate during exercise is correlated to blood viscosity and red cell aggregation. More recently we investigated this issue with the modelling of postexercise lactate kinetics, that allows a fair evaluation of lactate production by muscles (γ1) and lactate disappearance (γ2). Postexercise red cell aggregation (Myrenne …M1) appears to be correlated to γ2. Thus microcirculatory adaptations influenced by red cell aggregation may influence lactate disposal, adding its effect to that of the balance between carbohydrates and fat. On the other hand, the rise in blood lactate seems to induce some alterations in erythrocyte rheology at exercise. Correlations between its concentrations during exercise and erythrocyte rigidity support the concept that lactate, at least when it rises above the 4 mmol.l−1 threshold impairs red cell deformability. Moreover, it seems that endurance training influences erythrocyte response to lactate. While lactate did not in vitro affect erythrocyte aggregation, it impaired (as expected) erythrocyte deformability in sedentary subjects but it (unexpectedly) improved it in trained subjects. This difference may be due to training‐induced adaptations in erythrocyte metabolism, including transmembrane transfer via monocarboxylate transporters which show marked alterations in this context. This specific training‐induced pattern of response to lactate may provide an alternative explanation to the exercise‐induced arterial hypoxemia that occurs in such athletes. Show more

Keywords: Blood viscosity, plasma viscosity, hemorheology, erythrocyte deformability, erythrocyte aggregability, exercise, lactate, cossover concept, anaerobic threshold

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 331-337, 2004

Authors: Brun, Jean‐Frédéric | Varlet‐Marie, Emmanuelle | Cassan, Delphine | Manetta, Jérôme | Mercier, Jacques

Article Type: Research Article

Abstract: We previously reported in rugbywomen correlations between RBC deformability and the ability to oxidize at exercise more lipids. This surprising finding might of course be spurious, or reflect the importance of the balance of substrates at exercise on baseline parameters that regulate blood rheology. Actually, the capacity of skeletal muscle to utilize either lipid or carbohydrate as fuels strongly influences whole body metabolism both at rest and during exercise. While the healthy skeletal muscle has substantial metabolic flexibility and is able to switch from predominantly lipid o oxidation during fasting or endurance exercise to increased glucose oxidation in conditions of …insulin stimulation, obese individuals and those with type 2 diabetes manifest higher lipid oxidation during insulin‐stimulated conditions despite lower rates of lipid oxidation during fasting or prolonged exercise. A low ability to oxidize and to periodically deplete triglyceride in muscle is associated with raised blood lipids. In addition, high carbohydrate oxidation rates in the mitochondrion are likely to promote more free radical generation. An increase in either blood lipids or free radicals is likely to induce profound hemorheological effects. We present here hemorheological studies in various populations with the use of exercise calorimetry in order to assess this switch of substrates. These studies further evidence negative correlations between the ability to oxidize lipids at exercise and parameters of blood viscosity. Correlations found between RBC deformability and the ability to oxidize at exercise more lipids may be due to effects of endurance training on lipid oxidation which may in turn modify both lipid metabolism and free radical generation, thus influencing RBC rheology. Show more

Keywords: Blood viscosity, hemorheology, erythrocyte deformability, erythrocyte aggregability, substrate oxidation, mitochon‐ drion, crossover concept

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 339-343, 2004

Authors: Haider, L. | Snabre, P. | Boynard, M.

Article Type: Research Article

Abstract: Ultrasound scattering technique is used to investigate dynamics of reversible fractal aggregates in dense suspensions and analyze shear break‐up processes of Rayleigh fractal clusters. On the basis of an homogenous fractal flocculation and the hybrid scattering model in the Rayleigh scattering regime, a first order expression of the ultrasound scattering cross‐sectional area per unit of volume (backscattering coefficient) is derived for a dense distribution of correlated Rayleigh fractal clusters. From the scaling laws for shear break‐up of reversible aggregates in concentrated suspensions, a rheo‐acoustical study is then proposed to describe the shear stress dependence of the low frequency scattered power …per unit of volume. In a second part, experimental flow dependent changes of the ultrasound backscattering coefficient in a plane–plane flow geometry were reported to analyze shear break‐up processes of hardened or deformable red cell aggregates in polymer solution (neutral dextran polymer). Rheo‐acoustical experiments were examined within the framework of the effective mean field approximation and the proposed rheo‐acoustical model. The ability of ultrasound scattering to determine the critical disaggregation shear stress inducing a complete disaggregation and to give quantitative information on particle surface adhesive energy are finally analyzed. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 345-352, 2004

Authors: Shin, Sehyun | Ku, Yunhee | Park, Myung‐Su | Moon, Soo‐Yeon | Suh, Jang‐Soo

Article Type: Research Article

Abstract: The present study investigated the effect of transverse vibration on the hemo‐rheological characteristics of blood flow using a newly designed pressure‐scanning capillary viscometer. As a transverse vibration was applied, aggregated blood cells become disaggregated. Frequency of vibration was found to be the main parameter causing hemo‐rheological changes. For RBC suspension in a non‐aggregating medium (Dextran 40), increasing frequency of vibration caused decreased flow resistance. Meanwhile, flow resistance for whole blood increased with frequency of vibration. These seemingly contradictory results could be interpreted without conflict when a comprehensive mechanism of cell migration under vibration is elucidated. The present study confirmed that …vibration diminishes RBC aggregation, which triggers two different cell migration mechanisms and subsequently resulted in either increasing or decreasing the flow resistance. Show more

Keywords: Blood, resistance, aggregation, vibration, frequency, cell‐migration

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 353-358, 2004

Authors: Balan, Corneliu | Balut, Corina | Gheorghe, Liana | Gheorghe, Cristian | Gheorghiu, Eugen | Ursu, George

Article Type: Research Article

Abstract: The paper is concerned with the determination of blood permittivity and conductivity in Poiseuille and Couette simple shear flows. The experimental procedure, based on dielectric spectroscopy, evidences the sensitivity of blood electric properties to the applied frequency and local shear rate magnitude. The method evidences the possibility to correlate (for well‐defined flow geometry) magnitude of shear rate, and consequently the shear stress level, with spectra permittivity of blood.

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 359-364, 2004

Authors: Brun, Jean‐Frédéric | Aloulou, Ikram | Varlet‐Marie, Emmanuelle

Article Type: Research Article

Abstract: Among hemorheologic parameters, plasma viscosity is one of the most studied in epidemiology, so that it has emerged as an independent risk factor. In diabetes, plasma viscosity is frequently elevated. For this reason we tried to define characteristics of non‐insulin dependent diabetics with high plasma viscosity (>1.45 mPa.s) and whether they were more insulin resistant and/or exhibited other hemorheologic disturbances. 12 subjects (age 56.1±11.7; BMI 28.6±4.8) were thus found to have a value of plasma viscosity >1.45 mPa.s. They were compared to 20 age and BMI‐matched NIDDMs. Patients have similar insulin sensitivity, HbA1c, and fibrinogen. RBC aggregation, rigidity and hematocrit …were not significantly different. Whole blood viscosity at high shear rate was slightly higher (p=0.05). When corrected for hematocrit whole blood viscosity is no longer different. However, hematocrit was not lower in subjects with hpl >1.45. By contrast blood pressure was markedly higher (systolic: 177.5±2.5 mmHg vs 140±8 mmHg, p<10−8 ; diastolic 110±14 vs 83±9 mmHg, p<10−9 ; mean 132±18 mmHg vs 102±7 mmHg p<10−9 ). Therefore, in NIDDM, higher plasma viscosity, regardless insulin resistance and adiposity, is strongly related to blood pressure. Show more

Keywords: Blood viscosity, plasma viscosity, hemorheology, erythrocyte deformability, erythrocyte aggregability, insulin sensitivity, insulin resistance, minimal model, arterial hypertension

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 365-372, 2004

Authors: Velcheva, Irena | Titianova, Ekaterina | Antonova, Nadia

Article Type: Research Article

Abstract: During the last fifteen years some of our priority scientific topics of research were hemorheological and neurosonographic investigations in 229 patients with different forms of cerebrovascular diseases (CVD): 75 patients with asymptomatic CVD (ACVD), 65 patients with transient ischemic attacks (TIAs) and 89 patients with chronic unilateral cerebral infarctions (UCI). The findings were compared with 70 healthy persons. The main estimated hemorheological parameters were hematocrit (Hct), apparent whole blood viscosity (WBV), plasma viscosity (PV) and fibrinogen (Fib). They were correlated with the following sonographic parameters, obtained by extracranial and transcranial Doppler sonography: blood flow velocities (BFV) and peripheral resistance index …of Pourcelot (RP) of the major arteries of the head and the basal cerebral arteries and vasomotor reactivity indices (VMRI) of the middle cerebral arteries (MCA). Among the hemorheological variables the correlations of Hct with the velocity sonographic parameters predominated in all groups. Significant positive correlations between Hct, WBV and the RP of the internal carotid artery and MCA were found in patients with CVD. In UCI the increase in Hct and Fib was associated with a decrease in BFV of the collateral circulation where aging and high mean blood pressure were additional risk factors for impairment of the cerebral hemodynamics. Plasma viscosity was found to correlate with cerebral VMRI of MCA in patients with UCI. The clinical impact of these findings and their relation to the therapeutic strategy in CVD are discussed. Show more

Keywords: Hematocrit, fibrinogen, whole blood viscosity, Doppler sonography, blood flow velocity, cerebrovascular disease

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 373-380, 2004

Authors: Antonova, Nadia | Lazarov, Zdravko

Article Type: Research Article

Abstract: Hemorheological and hemodynamic effects of high molecular weight polyethylene oxide (PEO) solutions have been studied in vitro and in vivo at 30 experimental dogs. The rheological behaviour of the PEO solutions and of blood samples has been assessed by rotational viscometers at 20°C, 25°C and 37°C. An addition of PEO solutions to the blood in vitro has modified its rheological behavior, depending on the shear rates, concentration and temperature. Saline with aqueous PEO solutions at the concentration of 500 ppm has been infused into the blood circulation of the experimental dogs to achieve the total concentration in blood of 20–30 …ppm. The following parameters cardiac output, mean arterial blood pressure, central venous pressure, pulse frequency, blood volume flow in the femoral artery, total vascular resistance and blood viscosity before and after the infusion of PEO solutions have been studied. The main observed effect was a decrease of the hemodynamic resistance in the cardiovascular system up to 40% below the baseline after infusion of PEO solutions. Show more

Keywords: Polyethylene oxide solutions, hemorheology, hemodynamics

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 381-390, 2004

Authors: Varlet‐Marie, E. | Brun, J.‐F.

Article Type: Research Article

Abstract: In a previous paper we determined predictive equations for predicting viscosity parameters with whole body Bioelectrical impedance (BIA) in athletes. We have tried to extend this analysis to a sedentary population. 36 sedentary obese or insulin resistant patients (40.36±2.30 years; 85.77±3.54 kg; 165.93±1.56 cm) were enrolled into this study. Body composition was assessed with a multifrequency bioelectrical impedancemeter Dietosystem Human IM Scan that uses low intensity at the following frequencies: 1, 5, 10, 50 and 100 kHz. Analysis was performed with the software Master 1.0 that gives the choice among 25 published equations for body composition calculation. Viscometric measurements were …done at 1000 s−1 with a falling ball viscosimeter (MT 90 Medicatest). Hematocrit was measured with microcentrifuge. Two hemorheological parameters were independently correlated with impedance (Z) measurements at 50 kHz: whole blood viscosity (WBV) (r=0.541, p=0.01) and hematocrit (Hct) (r=−0.686, p=0.01). New equations slightly different from those we report in the previous paper were found. These findings confirm our previous reports of relationships between whole body electric properties and factors of blood viscosity in athletes and allow the use of BIA to a sedentary population. Obviously, extension of this study will be needed to determine if BIA can be used to generalize predictive equations in both sedentary and trained individuals. Show more

Keywords: Impedance, body fluids, blood viscosity, plasma viscosity, hemorheology

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 393-398, 2004

Authors: Urdulashvili, T. | Momtselidze, N. | Mantskava, M. | Narsia, N. | Mchedlishvili, G.

Article Type: Research Article

Abstract: It could be conjectured that the hemorheological disorders are involved in development of the ischemic heart disease. But this fact was so far insufficiently cleared up. The present studies were carried out in patients with various forms of chronic ischemic heart disease. We investigated the most significant factor of rheological disorders in the microcirculation, the erythrocyte aggregability, with a technique that provided us with the direct and quantitative data. Simultaneously we investigated in the same patients the tone of the resistance arteries of the hand with an original non‐invasive technique. We found that the erythrocyte aggregability increased almost twice in …the blood of investigated patients as compared to the healthy control group. The aggregability was positively correlated with severity of the disease. The most pronounced hemorheological disorders were found in the patients with the heart failure. As to the arteriolar resistance index, it was increased only in 45 per cent of all the investigated patients and no significant difference between the patients with the heart failure and without it was found available. We concluded that the blood rheological disorders represent themselves a factor that plays a significant role in pathogenesis of development of the heart disease. Show more

Keywords: Hemorheological disorders, arteriolar resistance, ischemic heart disease

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 399-401, 2004

Authors: Beridze, M. | Momtselidze, N. | Shakarishvili, R. | Mchedlishvili, G.

Article Type: Research Article

Abstract: The aim of study was the investigation of blood nitric oxide (NO) and nitrates (NO2 ) levels in 12 hours of ischemic stroke onset and establishment of correlation of these data with erythrocyte aggregability and initial ischemic lesion size. 48 patients, aged 45 to 70 years, 26 female, 22 male were investigated. Glasgow Coma Scale (GCS) and National Institute Health Stroke Scale (NIHSS) assessed initial neurological impairment. Patients were divided in mild and severe stroke groups. Control comprised 20 healthy individuals. Ischemic lesions were evaluated on conventional MRI scans. NO levels were measured by electron paramagnet resonance (EPR) method. …NO2 levels were defined by spectrophotometer method. Erythrocyte aggregability index (EAI) was measured by sound method [Biorheology 30(2) (1993), 153–161]. Pearson correlation and multivariate model of logistic regression was applied. Significant negative correlation was established between NO initial blood levels and the EAI (r=−0.75; p<0.001), as well as between blood NO2 and NO initial levels and ischemic lesion size (r=−0.79, p<0.01; r=−0.61, p<0.02, respectively). Endothelialy derived NO correlates with erythrocyte aggregability and probably has a positive impact on restoration of cerebral blood flow in the initial stage of acute brain ischemia. Show more

Keywords: Ischemia, nitric oxide, erythrocyte aggregation, microcirculation

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 403-406, 2004

Authors: Tatarishvili, J. | Momtselidze, N. | Mchedlishvili, G.

Article Type: Research Article

Abstract: Objective: To find whether the principal indices of blood rheological disorders related to the microcirculation undergo drastic changes during the traumatic shock. Methods: RBC aggregability and deformability, as well as the systemic hematocrit, were assessed in white laboratory rats with the techniques that provided us with direct and quantitative data. Results: We found that in the experimental animals the RBC aggregability was sharply increased, the RBC deformability significantly decreased, while the systemic hematocrit underwent considerable lowering during the traumatic shock. Conclusion: The blood rheological properties are significantly disordered during development of the traumatic shock.

Keywords: Microcirculation, blood rheological disorders, experimental traumatic shock

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 407-410, 2004

Authors: Vayá, Amparo | Ricart, Jose | Todolí, José | Micó, Luisa | Contreras, Teresa | Aznar, Justo

Article Type: Research Article

Abstract: Behçet's disease (BD) is associated with an increased thrombotic risk, although the prothrombotic mechanisms are not clearly defined. Alterations in blood rheology, specially increased erythrocyte aggregation has been suggested to play an important role in the development of thrombotic events in patients with Behçet's disease. In order to ascertain whether any rheological parameter could be involved in the pathogenesis of thrombotic events in Behçet's disease we have determined plasmatic lipids, fibrinogen, hematocrit, erythrocyte aggregation (Myrenne aggregometer), erythrocyte deformability (Rheodyn SSD), blood viscosity (Brookfield viscosimeter), plasma viscosity (Fresenius capillary viscosimeter) and erythrocyte indexes in Behçet's patients with a non‐active disease …when sampling, and a well matched control group. The patient group was made up of 40 Behçet's patients (20 male, 20 female aged 43±12 years) and the control group comprised 70 healthy volunteers (24 male, 46 female aged 45±13 years). Twelve of the 40 Behçet's patients have had a previous documented history of deep vein thrombosis at least six months before entering the study, and the other 28 did not. When patients and controls were compared, patients showed a statistically higher fibrinogen level (p=0.002), plasma viscosity (p=0.003), blood viscosity (p=0.021) and erythrocyte aggregation (p=0.049), the other rheological parameters not being statistically significant. No differences were observed in the rheological parameters when patients with and without a previous thrombotic episode were compared. Our results suggest that rheological alterations do not seem to play any role in the development of thrombotic events in patients with Behçet's disease. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 411-414, 2004

Authors: Solá, Eva | Vayá, Amparo | Contreras, Teresa | Falcó, Cristina | Corella, Dolores | Hernández, Antonio | Aznar, Justo

Article Type: Research Article

Abstract: The association of hemorheological alterations with morbid obesity remains a question of debate. In order to ascertain whether morbid obese subjects show certain hemorheological alterations which might be involved in the higher thrombotic risk which characterizes these subjects, we determine glucose, plasma lipids, apolipoproteins, fibrinogen, hematocrit, blood viscosity (Brookfield DVIII viscosimeter), both at native and corrected hematocrit of 45%, plasma viscosity (Fresenius capillary viscosimeter), erythrocyte aggregation (Myrenne aggregometer), both at stasis and at 3 s−1 at 45% hematocrit and erythrocyte indexes in 41 morbid obese subjects (32 female, 9 male aged 33±10 years), and in a well matched non‐obese …control group (40 female, 15 male, aged 32±10 years). Mean BMI in the morbid obese group was 44.9±6.7 kg/m2 vs 23.5±4.8 kg/m2 in the control group (p<0.001). Morbid obese subjects when compared with the control group showed a statistically higher glucose level (p<0.001), LDL‐cholesterol (p=0.019), triglycerides (p<0.001), apoB (p=0.019), apoB/A1 (p<0.001), fibrinogen (p<0.001), erythrocyte aggregation (p<0.001), and a statistically lower HDL‐cholesterol (p<0.001). No differences between both groups were observed regarding total‐cholesterol, plasma viscosity, blood viscosity and hematocrit (p=0.109; p=0.690; p=0.510; p=0.950), respectively. After the adjustment for BMI, differences in glucose, LDL‐cholesterol, triglycerides, apoB, apoB/A1 , and erythrocyte aggregation did not reach the statistical significance, and differences in fibrinogen were borderline significant (p=0.051), showing a direct effect of BMI on the detected differences between obese and non‐obese. Our results suggest that in morbid obese subjects the increased fibrinogen levels and the altered lipid profile associated with their higher BMI, could in addition to its known mechanisms on haemostasis, favour both venous and arterial thrombotic events by enhancing erythrocyte aggregation. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 415-418, 2004

Authors: Solá, Eva | Vayá, Amparo | Contreras, Teresa | Falcó, Cristina | Corella, Dolores | Hernández, Antonio | Aznar, Justo

Article Type: Research Article

Abstract: Discrepant results have been published regarding modifications of rheological parameters in obese subjects after a low caloric diet (LCD). In order to ascertain whether a decrease in BMI associated to a LCD, is accompanied by changes in the hemorheological parameters, we determined in 41 morbid obese subjects (32 female, 9 male aged 33±10 years) BMI, glucose, plasmatic lipids and apolipoproteins, fibrinogen, blood viscosity (Brookfield viscosimeter), plasma viscosity (Fresenius capillary viscosimeter), erythrocyte aggregation (Myrenne aggregometer), hematocrit and erythrocyte indexes, before starting on a LCD and 1 and 3 months after. During the first month obese subjects received a very low caloric …diet (VLCD) (Modifast® ) providing 458 kcal per day. The second and third month they received a LCD providing 1500 kcal/day for men and 1200 kcal/day for women. One month after starting on a VLCD, a statistical significant decrease in glucose (p<0.001), Total‐cholesterol (p<0.001), LDL‐cholesterol (p<0.001), triglycerides (p=0.012), apoB (p<0.001) and erythrocyte aggregation (p<0.001) were observed together with a concomitant decrease in BMI (p<0.001). The expected decrease in HDL‐cholesterol associated with a low fat diet was also noted in these individuals. No changes in fibrinogen, hematocrit, blood viscosity or plasma viscosity were observed. At 3 months only a slight increase in BMI was observed regarding the one month period, glucose being the only parameter which remained statistically lower. All the other significant parameters returned to their basal values at 3 months. VLCD (Modifast® ) is associated to a significant decrease in BMI with the corresponding improvement in glucose, lipids and erythrocyte aggregation at one month. However a LCD alone does not produce a further decrease in weight and both lipids and erythrocyte aggregation return to the basal situation at three months. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 419-422, 2004

Authors: Contreras, Teresa | Vayá, Amparo | Palanca, Sarai | Solá, Eva | Corella, Dolores | Aznar, Justo

Article Type: Research Article

Abstract: Some hemorheological parameters constitute risk factors for ischemic cardiovascular events. Most of these hemorheological factors are determined by the erythrocyte intrinsic properties and the high molecular weight plasmatic proteins, especially fibrinogen. The contribution of the plasmatic lipids to hemorheological factors is not well established. With this aim we determined hemorheological parameters in 112 healthy volunteers (62 males, 50 females) aged 35±10 years, range 19–54 years, members of our hospital staff. A complete set of rheological test was performed. Blood viscosity (BV) 230 sec−1 , plasma viscosity (PV), erythrocyte aggregation index (EAI), erythrocyte elongation index (EEI), hematocrit and fibrinogen. We …also determined plasmatic lipids including total cholesterol (T‐Ch) and its fractions (HDL‐Ch, LDL‐Ch, VLDL‐Ch), triglycerides, lipoproteins (Apo B, Apo A1 , B/A1 ). Exclusion criteria were concomitant cardiovascular risk factors or any other associated pathology. Our results show a positive correlation between BV 230 sec−1 and triglycerides (r=0.335) and negative with HDL‐Ch (r=−0.451) (p=0.01), respectively; PV shows a positive correlation with T‐Ch (r=0.297), LDL‐Ch (r=0.298) and Apo B/A (r=0.290) (p=0.01). The EEI was negatively correlated with TG (p=0.05). Of all the rheological parameters evaluated, EAI is the factor which shows the highest significant correlation with plasmatic lipids: T‐Ch (r=0.515), TG (r=0.303), LDL‐Ch (r=0.507) and Apo B/A ratio (r=0.403); (p=0.01). These results suggest that plasmatic lipids contribute to modulate the blood rheological properties, slowling blood flow, favouring the development of atherothrombotics events, especially in stenotic areas or bifurcations in the vascular tree. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 423-425, 2004

Authors: Kumsishvili, T. | Varazashvili, M. | Mchedlishvili, G.

Article Type: Research Article

Abstract: Hemorheological parameters were investigated before, during, and after the standard burn of the distal part of the rabbits' ear shell (54°C for 3 minutes). The erythrocyte aggregation was investigated with the “Georgian technique” and the local hematocrit was determined by centrifugation of blood samples from the inflammatory focus. In addition, we determined the size of the inflammatory edema in the ear shell. We found that the erythrocyte aggregability rised by 3.7 times in the venous blood flowing out from the inflammation focus while the hematocrit increased 1.6 times as compared to the microcirculation in the contralateral (control) ear shall. The …thickness of this latter related to edema development increased three times. All the mentioned changes disappeared within five days after start of the experiments. We concluded that in the aseptic inflammatory foci the erythrocyte aggregability increases considerably in the microcirculation producing capillary stases and enhancing the local hematocrit. The hemorheological disorders were not spread to other parts of the circulatory bed. Show more

Keywords: Rabbits experiments, blood rheological disorders, inflammation

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 427-429, 2004

Authors: Mantskava, Maya | Pargalava, Nugzar | Mchedlishvili, George

Article Type: Research Article

Abstract: Under both the in vivo and in vitro conditions we investigated the insulin effect on the most significant factor disturbing the blood rheological disorders in the microcirculation, the red blood cell aggregability. The in vivo studies we carried out in the 42 insulin treated diabetic patients (diabetes mellitus type II), as well as conducted the in vitro investigations of the blood both of the diabetic patients (24) and of the healthy people (20) where the insulin was added to the blood ex vivo. The RBC aggregability in blood investigated with the “Georgian technique” was found significantly enhanced, by about …100 per cents in the diabetic patients. Under the in vivo conditions insulin administered intravenously decreased the RBC aggregability almost to the normal level in diabetic patients. In addition, in the in vitro studies we found that the insulin lowered significantly the RBC aggregability when it was significantly enhanced by addition of Dextran‐500, as well as in the blood of patients with the ischemic brain infarcts. The decreasing effect on the RBC aggregability was observed even in the healthy control group where the RBC aggregability was in a normal range. Show more

Keywords: Microvascular hemorheology, diabetus melitus, insulin effect

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 431-433, 2004

Authors: Musielak, Malgorzata

Article Type: Research Article

Abstract: Bovine red blood cells (RBCs) do not exhibit any aggregation tendency in autologous plasma and, therefore, all bovine rouleaux obtained in vitro are regarded as artificial. The present study reports the bovine RBC rouleau formation by either bovine or human fibrinogen and Ca2+ ions. The phenomenon was induced through two‐step cell incubation: in 0.9% NaCl and 1% bovine albumin at 37°C for 30 min followed by 20 hrs incubation at 30°C in the fresh solution supplemented with 10 mM glucose. Its mechanism is unknown. During the incubation the number of N‐glycolylneuraminic acid molecules per cell decreased from 48.1 to …44.9 amoles, which accounted for 7%. The treatment of RBCs with V. cholerae sialidase under the same conditions resulted in a 94% drop in the Neu5Gc quantity and did not induce the rouleau formation in the same fibrinogen preparation. The preliminary results rise a question whether the bulk of sialic acid is required in the aggregation of bovine erythrocytes under static conditions. Only a minor pool of Neu5Gc seems to be responsible for suppression of the phenomenon. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 435-438, 2004

Authors: Stoeff, S. | Vretenarska, M. | Stojanova, N. | Halacheva, S. | Jovtchev, Sv. | Tsaneva, M. | Galabova, T. | Trifonova, N. | Penev, M.

Article Type: Research Article

Abstract: A probable conjunction of hemodynamic‐ and rheological variables was tested in hypertensive patients. Most pronounced correlation was fixed for some indices (sizable in value for plasma viscosity and small but distinct for blood pressure and ZSR) vs. total peripheral resistance. These results of a small scale elaboration are encouraging to get up a study extension.

Keywords: Arterial hypertension, blood rheology disturbance, total peripheral resistance

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 439-441, 2004

Authors: Konstantinova, Elena | Tolstaya, Tatiyana | Prishchep, Sergey | Milutin, Alexander | Mironova, Elena | Ivanova, Lilia

Article Type: Research Article

Abstract: It has been reported that dyslipidemia is associated with rheological and microcirculatory abnormalities in patients with ischaemic heart disease. However, it is not known how this system changes in men and women with ageing. In healthy young and middle‐aged subjects the following parameters were evaluated: total plasma cholesterol, triglycerides and HDL‐cholesterol levels, deformability of erythrocytes, red blood cell and platelet aggregations, blood and plasma viscosity, neutrophils' cytosolic [Ca$^{2+}]\tsub{i}$ and microviscosity of the bilayer's total lipid phase and the annular near‐protein zone of the membranes. Using intravital computer‐associated microscopic system we investigated the microcirculation of bulbar conjunctiva. Oxygen transfer …characteristics were measured with a Radiometer TCM2 monitor. It is evident from the data obtained that in men of middle age the total plasma cholesterol and triglyceride levels are higher in comparison with other groups. The rheological behavior of red blood cell and platelet aggregations in men differ from that in women. Neutrophils activation in healthy subjects was not recorded. Our results show that changes of the blood rheological properties of men 35–50 years old can lead to disturbances of the microcirculation. Show more

Keywords: Cholesterol, lipids, microcirculation, blood viscosity, erythrocytes, deformability, aggregation

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 443-448, 2004

Authors: Plotnikov, M.B. | Plotnikov, D.M. | Aliev, O.I. | Maslov, M.Yu. | Vasiliev, A.S. | Alifirova, V.M. | Tyukavkina, N.A.

Article Type: Research Article

Abstract: The clinical trials on 31 patients with arteriosclerosis and I‐II stage discirculatory encephalopathy to assess an ability of Ascovertin to limit hemorheology abnormalities were carried out. In patients with discirculatory encephalopathy was a distinct increase in blood viscosity which was induced by disturbances of cell rheological factors: increase in aggregation of erythrocytes and decrease in their deformability were observed in comparison with indices in the group of healthy volunteers. No difference in plasma viscosity and fibrinogen was found. The treatment with Ascovertin in patients with discirculatory encephalopathy improved their attention, memory, mental performance, normalized sleep, releaved headache, decreased fatiquebility, led …to the decrease in blood viscosity values, the reduction of pathological erythrocyte hyper aggregation and the improvement of erythrocyte deformability. We partly connect this clinical effect and hemorheology activity of Ascovertin with its antioxidant property – there was found impressive lipid peroxidation suppression. No significant changes in hemorheological and lipid peroxidation indices were observed in patients without Ascovertin. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 449-452, 2004

Authors: Bolokadze, N. | Varazashvili, M. | Salia, N. | Momtselidze, N. | Solomonia, R. | Mchedlishvili, G.

Article Type: Research Article

Abstract: The aim of the present study was investigation of the lipid peroxidation changes within the erythrocytes under conditions of increased RBC aggregation. This latter was produced both in the in vitro and in vivo conditions by the addition of Dextran T‐500. For the in vitro studies blood samples were taken from the cubital veins of 15 healthy subjects. During the in vivo studies 10 ml of the 10 per cent Dextran T‐500 solution was administered intravenously in six chinchilla rabbits. Another six animals were treated with rheopolyglucyne. The RBC aggregation in blood was investigated with the “Georgian technique”. The malondialdehyde …(the end product of lipid peroxidation) was determined in all cases by its reaction with thiobarbituric acid. We found that in the in vitro conditions, as well as in the in vivo studies, the lipid peroxidation was significantly increased in the erythrocytes during the enhanced RBC aggregation induced by addition of Dextran T‐500. Therefore we suppose that the elevated RBC aggregation cause an increase of cell's lipid peroxidation and it is possible to think that appropriate prooxidant: antioxidant balance is shifted toward the pro‐oxidants in the erythrocytes. Show more

Keywords: RBC aggregation, lipid peroxidation, in vitro studies, in vivo studies, Dextran T‐500

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 453-455, 2004

Authors: Pargalava, Nugzar | Mantskava, Maya | Mchedlishvili, George

Article Type: Research Article

Abstract: We investigated the RBC aggregability in the patients with the foot diabetic gangrenes: in the venous blood samples taken from the damaged foot before its amputation, as well as from the cubital vein (the systemic circulation). The RBC aggregability was investigated with the “Georgian technique” that is sensitive and provided us with direct and quantitative data. We found that the RBC aggregability was higher by about 20%, in the blood flowing from the gangrenous tissue than in the systemic circulation. Therefore, the sources of the systemic hemorheological disorders were the primarily damaged tissues. Taking into account that the blood is …uninterruptedly flowing and mixing together in the whole circulatory bed we conclude that in the systemic circulation a certain compensatory mechanism provide for a partial normalization of the blood rheological properties, since the RBC aggregability never reaches the level in the blood of the healthy people. Show more

Keywords: Microvascular hemorheology, diabetic gangrene, RBC aggregation

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 457-459, 2004

Authors: Sordia, T. | Tatarishvili, J. | Varazashvili, M. | Mchedlishvili, G.

Article Type: Research Article

Abstract: We analysed hemorheological disorders in the microcirculation of intestinal mesenterium of adult laboratory rats following massive exsanguinations when the mean arterial pressure dropped and then the hemorrhagic shock developed in the animals. The mesenteric microcirculation was analysed by the Texture Analysis System (Leitz, Wetzlar): (a) diameters of the afferent arterioles, capillaries, and efferent venules; (b) the blood flow velocity; (c) microvascular blood flow changes (during the RBC aggregation); (d) local microvascular hematocrit; and (e) the transformation of capillaries into plasmatic microvessels. During development of the hemorrhagic shock we found that the blood flow velocity decreased in all microvessels, there …was an increased RBC aggregation which gradually enhanced in the mesenteric microvessels' lumen causing blood flow slowing down till appearance of stases. A part of the capillaries transformed into plasmatic vessels. Therefore the microcirculation demonstrated a significant decrease, this being related both to the lowered pressure gradient and to specific hemorheological disorders in the capillary networks. Show more

Keywords: Hemorheological disorders, microcirculation, hemorrhage

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 461-462, 2004

Authors: Piagnerelli, M. | Zouaoui Boudjeltia, K. | Piro, P. | Brohee, D. | Vanhaeverbeek, M. | Vincent, J.L.

Article Type: Research Article

Abstract: Several recent in vitro studies have observed that alterations in red blood cell (RBC) rheology depend on sample temperature. This possibility could limit the in vivo validity of the assessment of RBC shape. We investigated the effects of sample temperature on RBC shape estimated by flow cytometry in septic patients compared with those of volunteers. 0.5 ml of blood was placed at 4°C, room temperature (20°C) or at 37°C. RBCs were analyzed at 30 minutes (T30) by flow cytometry and results compared to baseline measures. With the flow cytometry technique, the RBC shape of healthy volunteers shows a bimodal distribution …related to the biconcave form. On this histogram, we calculated the second Pearson coefficient of dissymmetry – PCD – representing the asymmetry of this histogram. At baseline, RBC PCD was increased in septic patients representing a more spherical shape compared to volunteers (−0.73±0.18 versus −0.95±0.05; p=0.007). For both groups, RBC shape estimated by the flow cytometry technique was not modified by the temperature of the sample. We conclude that estimation of RBC shape by flow cytometry is not influenced by the temperature of the sample. The present study validates the flow cytometry technique to assess RBC shape in vitro. Show more

Keywords: Red blood cell, flow cytometry, shape, temperature, sepsis

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 463-466, 2004

Authors: Shin, Sehyun | Ku, Yunhee | Park, Myung‐Su | Suh, Jang‐Soo

Article Type: Research Article

Abstract: A newly designed pressure‐scanning capillary viscometer is extended to measure the viscosity of whole blood over a range of shear rates without the use of anticoagulants in a clinical setting. In the present study, a single measurement of pressure variation with time replaces the flow rate and pressure drop measurements that are usually required for the operation of a capillary tube viscometer. Using a pressure transducer and capillary, we measured the variation of pressure flowing through capillary tube with respect to time, p(t), from which viscosity and the shear rate were mathematically calculated. For water and anticoagulant‐added bloods, there was …an excellent agreement found between the results from the pressure scanning capillary viscometer and those from a commercially available rotating viscometer. Also, the pressure‐scanning capillary viscometer measured the viscosity of whole blood without heparin or EDTA. This new method overcomes the drawbacks of conventional viscometers in the measurement of whole blood viscosity. First, the pressure‐scanning capillary viscometer can accurately and consistently measure the whole blood viscosity over a range of shear rates in less than 2 min without any anticoagulants. Second, this design provides simplicity (i.e., ease of operation, no moving parts, and disposable) and low cost. Show more

Keywords: Blood, viscosity, shear rate, pressure, capillary viscometer

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 467-470, 2004

Authors: Varlet‐Marie, E. | Brun, J.‐F.

Article Type: Research Article

Abstract: Bioelectrical impedancemetry (BIA) has been used to evaluate hemorheological parameters from whole body measurements. In a previous study, we have determined a set of predictive equations for hematocrit, whole blood viscosity and plasma viscosity in athletes. In another previous study, we also found other predictive equations in sedentary lean and obese subjects. This study aims at developing more generalized BIA‐derived predictive equations for hemorheological parameters in both sedentary and trained individuals. 72 subjects, either athletes, sedentary obese or insulin resistant patients (33.57±1.60 yr; 80.81±2.06 kg; 171.03±1.19 cm) were enrolled into the study. Body composition was assessed with a multifrequency bioelectrical …impedancemeter (Dietosystem Human IM Scan) using low intensity at the following frequencies: 1, 5, 10, 50 and 100 kHz. Viscometric measurements were done at 1000 s−1 with a falling ball viscosimeter (MT 90 Medicatest). Hematocrit (Hct) was measured with microcentrifuge. Hematocrit was correlated with impedance (Z) measurements at 50 kHz (r=−0.591, p=0.01). A generalized empirical predictive equation can thus be proposed. These findings further suggest that one can predict hematocrit in the general population with whole body electric properties. Show more

Keywords: Impedance, body fluids, blood viscosity, hemorheology, hematocrit, athlete, sedentary population

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 471-475, 2004

Authors: Antonova, Mariya

Article Type: Research Article

Abstract: The viscoelastic characteristics – modulus of elasticity, natural frequency, coefficient of viscosity and low‐frequency resonance curve can be used as diagnostic indicators, at assessment of the direct effect of vasoactive drugs, and at selection of natural and artificial arterial prostheses. The aim of this work is a device for measurement of the viscoelastic characteristics of cylindrical segments of arteries in vitro and of arterial prostheses to be developed. The cylindrical segment is subjected to low frequency sinusoidal pulsations of the inner pressure. On the basis of the amplitude of the response oscillations of the wall, measured using the volume pulsations …of the segment, the resonance curve is built so that the dynamic characteristics – modulus of elasticity, natural frequency, and coefficient of viscosity can be calculated. The living specimens are perfused with nutrition solution for keeping the quasi‐physiological conditions. In the same way, cylindrical segments of rubber and artificial human prostheses were investigated. The sensitivity and the accuracy of the device are given. The construction permits to keep the vitality of native animal's specimens when the measurements are carried out. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 477-480, 2004

Authors: Zvetkova, E. | Savov, Y. | Gluhcheva, Y. | Ilieva, I. | Bichkidjieva, E. | Katzarova, E. | Tsenov, I.

Article Type: Research Article

Abstract: The morphological characteristics of granulocyte/macrophageal (GM‐) colonies and clusters, obtained in vitro (in semi‐solid agar cultures) from bone marrow hematopoietic myeloid progenitors pertain to leukocyte hemorheology of healthy persons and patients with myeloid leukemias. The morphological features of in vitro growing myeloid progenitors, granulocytes and macrophages of healthy persons differ in their cell size, shape and degree of differentiation from the cultivated marrow cells in cases of acute and chronic myeloid leukaemia. In this malignant disease, the rheological properties of leukocytes (granulocytes/macrophages) were found to provide diagnostic information. Further studies should be undertaken to examine whether the method could be …useful in defining survival, prognosis and therapeutical approach in cases of myeloid leukemia. Show more

Keywords: Human bone marrow agar cultures, granulocyte/macrophageal (GM‐) colonies and clusters in vitro, morphological/rheological features of myeloid cells, healthy persons and myeloid leukemia patients

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 481-484, 2004

Authors: Forconi, Sandro

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 485-486, 2004

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 30, no. 3-4, pp. 487-495, 2004