Clinical Hemorheology and Microcirculation - Volume 33, issue 4

Authors: Ramelet, A.A. | Boisseau, M.R. | Allegra, C. | Nicolaides, A. | Jaeger, K. | Carpentier, P. | Cappelli, R. | Forconi, S.

Article Type: Research Article

Abstract: Background: Veno-active drugs (VAD) have effects on edema and symptoms related to chronic venous disease (CVD), especially so-called venous pain. VAD's effectiveness, although well established, is regularly debated. Objective: Our purpose was to select all randomized controlled trials (RCTs) and meta-analyses devoted to VAD and symptoms in CVD, to submit them to a group of international experts in CVD and to vote with secrete ballot to determine the level of efficacy of each drug, according to EBM (Evidence-Based Medicine) rules and critical analysis. Methods: Publications in any language devoted to VAD and venous symptoms were searched for in different databanks …and submitted to the experts prior to the meeting. Results: 83 papers were analyzed, including 72 RCTs or meta-analyses. Experts determined the level of EBM of each drug, according to the literature and personal experience, using 3 levels of recommendation, A, B and C (from large RCTs to non-randomized trials). Conclusions: VAD are effective and may be applied in CVD when symptomatic, from C0s to C6s. However, etiological treatment of venous reflux and venous hypertension has always priority. In some cases VAD may replace compression and/or complement its effects. If respecting these prerequisites, VAD are safe and effective. Show more

Keywords: Chronic venous disease, edema, venous pain, veno-active drugs, consensus, evidence-based medicine

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 309-319, 2005

Authors: Windberger, U. | Plasenzotti, R. | Voracek, Th.

Article Type: Research Article

Abstract: The large cellular volume of erythrocytes and the increased plasma concentration of proteins in elephants are factors which potentially affect blood rheology adversely. To verify blood rheology, routine hemorheologic variables were analyzed in four African elephants (Loxodonta africana), housed in the zoo of Vienna. Whole blood viscosity at three different shear rates (WBV at low shear rate: WBV 0.7 s−1 and WBV 2.4 s−1 ; WBV at high shear rate: WBV 94 s−1 done by LS30, Contraves) and erythrocyte aggregation (aggregation indices AI by LS30; aggregation indices M0, M1 by Myrenne aggregometer) were high (WBV 94 s−1 : …5.368 (5.246/5.648); WBV 2.4 s−1 : 16.291 (15.605/17.629); WBV 0.7 s−1 : 28.28 (25.537/32.173) mPa s; AI 2.4 s−1 : 0.25 (0.23/0.30); AI 0.7 s−1 : 0.24 (0.23/0.28); M0: 7.8 (6.4/8.4); M1: 30.2 (25/31)). Plasma viscosity (PV) was increased as well (1.865 (1.857/1.912) mPa s) compared to other mammalian species. These parameters would indicate a decrease in blood fluidity in elephants. However, erythrocyte rigidity (LORCA, Mechatronics) was decreased, which in contrast, has a promotive effect on peripheral perfusion. Blood rheology of the elephants was determined by a high whole blood and plasma viscosity as the result of pronounced erythrocyte aggregation and high plasma protein concentration. Thus, in the terminal vessels the resistance to flow will be increased. The large erythrocytes, which might impede blood flow further due to geometrical reasons, however, had a pronounced flexibility. We conclude that the effect of the increased inner resistance to peripheral blood flow was counteracted by the decreased rigidity of the erythrocytes to enable an adequate blood flow in African elephants. Show more

Keywords: Blood, elephants, erythrocyte aggregation, erythrocyte rigidity, hematology, rheology, viscosity

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 321-326, 2005

Authors: Kavitha, Anandan | Ramakrishnan, Swaminathan

Article Type: Research Article

Abstract: The mechanics of red blood cell shape changes under normal and deformed conditions are analyzed using wavelet based approach. Images of intact and deformed human red blood cells obtained from normal adults are subject to morphological image processing and the corresponding shape descriptions at two different levels of approximations using different wavelet functions are analyzed. The results demonstrate that using wavelets it is possible to classify normal and deformed red blood cell shapes. Uniform and consistent results are obtained for cells with similar shapes, for all chosen wavelet functions. The variation indices are significant (p<0.005) for all the chosen wavelet …functions at both the approximation levels. Further it seems that this approach could be useful for identifying closely identical cell shapes. As cell shape deformations are significant in describing the flow behavior in micro or macro vessels the study seems to be clinically relevant. The methodologies, algorithms and observations based on wavelet based analysis are discussed in detail. Show more

Keywords: Red cell shapes, wavelet transforms, microvasculature, blood flow

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 327-335, 2005

Authors: Vigilance, Jacqueline E. | Reid, Harvey L.

Article Type: Research Article

Abstract: Since persistent uncontrolled hyperglycaemia predisposes to vascular complications in diabetics, this study aimed at assessing the relationship of glycaemic control to plasma fibrinogen concentration, relative plasma viscosity and ankle arterial blood flow in diabetic patients with (N=28) and without neuropathy (N=34) compared with non-diabetic controls (N=21). Glycaemic control was determined by total glycated haemoglobin (GHb) levels. Patients were placed into three categories of glycaemic control, namely good (GHb 4–<8%), fair (GHb 8–12%) and poor (GHb>12%). Compared with non-diabetics, blood flow was significantly higher (p<0.05) in patients with good but not poor glycaemic control. Fibrinogen was significantly higher in patients …with fair and poor glycaemic control than in non-diabetic subjects (p<0.05). In non-neuropathic patients, viscosity was higher (p<0.05) in those with fair control and significantly different (p<0.05) between those with fair and poor control. The results suggest that the initial vasodilatation in the periphery is attenuated by poor glycaemic control, contributing to the decrease in ankle arterial blood flow as a consequence of the simultaneous increase in plasma fibrinogen and viscosity. These adverse changes may contribute to the development of the diabetic foot. Show more

Keywords: Glycaemic control, ankle blood flow, plasma fibrinogen concentration, relative plasma viscosity

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 337-346, 2005

Authors: Xu, Xiaofeng | Zeng, Zhu | Yao, Weijuan | Sun, Dagong | Ka, Weibo | Zhou, Shupei | Wen, Zongyao

Article Type: Research Article

Abstract: The purpose of this study was to examine the changes of hemorheological properties of erythrocytes in the nude mice with erythroleukemia and the treatment effects of etoposide (VP16). Thirty mice were randomly divided into three groups: the control group (C group), injected with 1 ml saline solution, the MEL group (M group) injected with 1 ml MEL (murine erythroleukemia cell line) and the MEL + VP16 group (V group) injected with 1 ml MEL and from the 8th day after injection, 20 μl VP16 (1 μg/μl) was injected intraperitoneally every five days. One week after MEL injection, erythroblastic cells increased …in the bone marrow and proerythroblasts were found in the peripheral blood, suggesting that erythroleukemia was induced. Abnormalities were also found in spleens and livers later. At around twenty days after injection, the mice in M group died and about four weeks after injection, the mice in V group also died. Compared with C group, the hemorheological indexes [the deformation index DI, orientation index (DIor ), and the small deformation index (DId )], electrophoretic mobility, membrane fluidity as well as osmotic fragility of red blood cells (RBC) in M and V groups changed significantly. But after VP16 administration, the changes of above parameters in V group were less significant than those of M group. The results above suggested that intraperitoneal injection of MEL cells could cause erythroleukemia in nude mice, VP16 could alleviate the erythroleukemia symptom and improve the hemorheological properties, and could prolong V group nude mice survival. Show more

Keywords: Erythroleukemia, murine erythroleukemia cell line, etoposide, hemorheology

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 347-361, 2005

Authors: Bor-Kucukatay, Melek | Meiselman, Herbert J. | Başkurt, Oguz K.

Article Type: Research Article

Abstract: The role of nitric oxide (NO) in maintaining normal mechanical behavior of red blood cell (RBC) has been previously demonstrated. The effects of NO donor and NOS inhibitor on the mechanical properties of density fractionated RBC were tested in this study. A non-specific NOS inhibitor, N-omega-nitro-L-arginine methyl ester (L-NAME) at a concentration of 10−3 M and sodium nitroprusside (SNP), a nitric oxide donor at a concentration of 10−6 M was added to blood samples with hematocrit adjusted to 0.4 l/l and RBC deformability was measured by an ektacytometer in the density fractionated RBC after one hour incubation at …37°C. There was no significant effect of the NO donor SNP on cellular deformability in the older (denser) RBC fraction in contrast with the younger (least dense) fraction. Alternatively, the sensitivity of cellular deformability to competitive NOS inhibition by L-NAME was greater in the older fraction. These findings suggest that older RBC are characterized by diminished internal NO synthesis and are also less sensitive to external NO indicating that the target mechanisms for NO may also be deteriorated. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 363-367, 2005

Authors: von Känel, Roland | Loredo, José S. | Powell, Frank L. | Adler, Karen A. | Dimsdale, Joel E.

Article Type: Research Article

Abstract: Hemostatic changes might contribute to the increased risk of cardiovascular and cerebrovascular events in patients with obstructive sleep apnea (OSA). We investigated the effect of a short-term isocapnic hypoxic challenge on coagulation activation markers thrombin/antithrombin III complexes (TAT) and D-dimer in OSA. Thirty-two OSA patients (mean age 48±11 years) inhaled a gas mixture containing 10% O2 and 90% N2 and further adjusted to yield pulse oximetry saturation of 80–85% for 5 minutes. Plasma levels of TAT and D-dimer were measured immediately before and immediately after the hypoxic challenge. The hypoxic challenge provoked a significant increase in TAT (p<0.001) …and in D-dimer (p=0.037). Mean nocturnal oxygen saturation from the sleep recordings correlated with D-dimer increase (r=−0.37, p=0.041). Also, OSA patients with a history of hypertensive parents had greater D-dimer increase in response to hypoxia than patients having normotensive parents (p=0.035). Parental hypertension independently explained 15% of the variance in D-dimer increase after hypoxia (p=0.035). Oxygen desaturation during sleep may predispose OSA patients, in particular those with a parental history of hypertension, to a hypercoagulable state providing one explanation for the increased risk of atherothrombotic events in this population. Show more

Keywords: Blood coagulation, cardiovascular disease, hypoxia, sleep apnea, sympathetic nervous system

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 369-377, 2005

Authors: Holdt, Birgit | Lehmann, Jochen K. | Schuff-Werner, Peter

Article Type: Research Article

Abstract: Viscometry is an often applied method in clinical chemistry. A variety of studies demonstrate an association of parameters related to blood viscosity with human pathology of varying origin. Whole blood and plasma viscosity are considered to be clinically useful indicators in the diagnostic workup and therapy monitoring of certain diseases. In this study, we compare the “Waegeviskosimeter” (WV) described in previous publications with a newly developed device, the “Reverse Flow Viscometer” (RFV). Both viscometers are capillary flow viscometers. Both overcome the disadvantage of common viscometers of the Ubbelohde and Cannon-Fenske type which require large amounts of plasma and which can …be only applied to Newtonian fluids. The accuracy of the measurements of both viscometers, requiring less than 1.0 ml sample volume, is superior to most conventional methods. The major distinction in the functionality of the WV and the RFV is that the WV measures the kinematic viscosity whereas the RFV directly estimates dynamic viscosity without the requirement of additional density measurement. We found good reproducibility of viscosity with coefficient of variation CV≤1.1% for both viscometers. Quality assurance measures have been carried out. Because no quality assurance scheme according to the guidelines proposed by the German Medical Association exists for plasma or whole blood viscosity, we tested reference material Lyphochek Unassayed Chemistry Control Level 1 and Level 2 (Bio-Rad Laboratories). We determined the viscosities 1.40 mPa s and 1.08 mPa s (37°C) and the between-run precision from daily quality control runs with CV of 1.4% and 1.2% for the WV, and 1.7% and 1.4% for the RFV. For direct comparison reasons, we determined the viscosity in seventy human plasma and serum samples by both methods. Using the regression analysis described by Passing–Bablok, the RFV and the WV methods are highly correlated and show only little variations (r=0.990, τ=0.896). The regression equation is yWV =1.035xRFV −0.056 with a mean deviation of 0.4±3.6%. We conclude that both new devices for viscosity assessment fulfill all quality requirements as prescribed for clinical chemical laboratories. One advantage RFV is to measure the dynamic viscosity directly. Show more

Keywords: Hemorheology, blood viscosity, viscometer, quality assurance, evaluation of viscometer

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 379-387, 2005

Authors: Ricart, José M. | Vayá, Amparo | Todolí, José | Santaolaria, M. Luisa | Calvo, Javier | Aznar, Justo

Article Type: Research Article

Abstract: Behçet's disease (BD) is a chronic systemic vasculitis characterised by recurrent oral and genital ulcers and uveitis, in which 25–30% of patients develop thrombotic events of unknown etiology. In order to ascertain whether erythrocyte aggregation (EA) may be involved in thrombotic events and or uveitis in BD patients, we determined using two erythrocyte aggregometers i.e. Myrenne and Sefam (which provides the total disaggregation threshold, needed for erythrocytes to disaggregate), EA in 77 BD patients (42 male, 35 female, aged 44±12 years) and 77 controls (41 male, 36 female, aged 43±11 years). BD patients showed higher EA determined with both aggregometers: …Myrenne (EA0 : P=0.035; EA1 : P<0.001) or the Sefam (Ta: P<0.001, AI10 : P<0.001, γD: P=0.014) as well as higher fibrinogen and triglyceride levels (P<0.001, P=0.003, respectively) compared with the control group. However no differences were observed in any of the aggregation parameters determined either with the Myrenne (EA0 , EA1 ) or the Sefam (Ta, AI10 , γD) aggregometer when BD patients with thrombotic events (n=23) or uveitis (n=21) were compared with those who did not (P>0.05). These results reinforce previous findings of our group, suggesting that EA does not seem to be involved in thrombotic events or in uveitis in BD patients. Show more

Keywords: Erythrocyte aggregation, Behçet's disease, Sefam and Myrenne aggregometer, thrombosis, uveitis

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 389-396, 2005

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 33, no. 4, pp. 397-398, 2005