Clinical Hemorheology and Microcirculation - Volume 9, issue 2
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Clinical Hemorheology and Microcirculation, a peer-reviewed international scientific journal, serves as an aid to understanding the flow properties of blood and the relationship to normal and abnormal physiology. The rapidly expanding science of hemorheology concerns blood, its components and the blood vessels with which blood interacts. It includes perihemorheology, i.e., the rheology of fluid and structures in the perivascular and interstitial spaces as well as the lymphatic system. The clinical aspects include pathogenesis, symptomatology and diagnostic methods, and the fields of prophylaxis and therapy in all branches of medicine and surgery, pharmacology and drug research.
The endeavour of the Editors-in-Chief and publishers of
Clinical Hemorheology and Microcirculation is to bring together contributions from those working in various fields related to blood flow all over the world. The editors of
Clinical Hemorheology and Microcirculation are from those countries in Europe, Asia, Australia and America where appreciable work in clinical hemorheology and microcirculation is being carried out. Each editor takes responsibility to decide on the acceptance of a manuscript. He is required to have the manuscript appraised by two referees and may be one of them himself. The executive editorial office, to which the manuscripts have been submitted, is responsible for rapid handling of the reviewing process.
Clinical Hemorheology and Microcirculation accepts original papers, brief communications, mini-reports and letters to the Editors-in-Chief. Review articles, providing general views and new insights into related subjects, are regularly invited by the Editors-in-Chief. Proceedings of international and national conferences on clinical hemorheology (in original form or as abstracts) complete the range of editorial features.
The following professionals and institutions will benefit most from subscribing to
Clinical Hemorheology and Microcirculation: medical practitioners in all fields including hematology, cardiology, geriatrics, angiology, surgery, obstetrics and gynecology, ophthalmology, otology, and neurology. Pharmacologists, clinical laboratories, blood transfusion centres, manufacturing firms producing diagnostic instruments, and the pharmaceutical industry will also benefit.
Important new topics will increasingly claim more pages of
Clinical Hemorheology and Microcirculation: the role of hemorheological and microcirculatory disturbances for epidemiology and prognosis, in particular regarding cardiovascular disorders, as well as its significance in the field of geriatrics. Authors and readers are invited to contact the editors for specific information or to make suggestions.
Abstract: The instrument precision and between-patient variability of haemorheological measurements have been determined using six commercially available instruments: Technicon Ektacytometer, Contraves LS30, SEFAM Erythro-Agregametre, IMH Hemorheometre, Carri-Med St. George’s Filtrometer, and ABX Cell Transit Analyser. Instrument performance was similar at 25°C and 37°C. The different instruments, and sometimes the different parameters of one instrument, showed important differences in precision. Variability of results between patients was often greater than between healthy subjects. The results indicate that both instrument precision and biological variability should be determined in advance of rheological studies so that the required number of subjects can be estimated. A nomogram…is presented to facilitate determination of sample size for studies in which the data are to be analysed by either parametric or non-parametric tests.
Abstract: This paper deals with the study of comparison of haemorheological parameters between normal controls (NC) and cases of acute infections (INFA) in pediatric age group.The haemorheological parameters studied include haematocrit, whole blood viscosity, red cell aggregation and red cell deformability. Of all the haemorheological parameters the values of haematocrit,whole blood viscosity, plasma viscosity and red cell aggregation expressed as corrected E.S.R. (ESRSt Pv Ht ) and also estimated by Schmid Schonbein’s photometric method expressed as MEA index are significantly altered.
Abstract: The functional involvement of the previously characterized high affinity binding of leukotriene C4 (LTC4 ) in human red blood cells (RBC) has been investigated. By using a filtration technique in vitro, it was demonstrated that LTC4 reduced erythrocyte deformability at low concentrations (10 −10 - 10−6 mol. I−1 ). This effect is highly specific since LTD4 did not decrease the filterability of the cells. Factors affecting the binding also modified the filtration index. The possible role of this leucocyte metabolite in hemorheological disturbances including RBC deformability is suggested.
Abstract: Blood rheology and platelet function were studied serially in 23 patients with unstable angina compared to 70 healthy controls. On admission, the angina patients had raised blood viscosity at, any shear rate (m ± SEM) at = 0.94 sec−1 : 17.3 ± 0.5 vs 14.7 ± 0.2 mPas; p<.001), plasma viscosity (1.32 ± 0.02 vs 1.22 ± 0.01 cSt; p<.001), and erythrocyte aggregation index (16.2 ± 0.7 vs 14.6 ± 0.4; p<.01). Plasma fibrinogen, plasma protein concentration, hematocrit and erythrocyte filterability were not different from those of the control group. ADP platelet aggregation in vitro was normal, but plasma levels…of β -thromboglobulin (65.3 ± 9.5 vs 31.1 ± 1.3 ng/ml; p<.001), of platelet factor 4 (24.7 ± 4.5 vs 6.6 ± 0.6 ng/ml; p<.001) and of platelet malonyldialdehyde (5.6 ± 0.5 vs 5.0 ± 0.2 nmol/109 platelets; p<.05) were significantly higher. The hemorheological and platelet abnormalities observed on admission in the patients who later developed complications (that is, who had infarctions or a recurrence of angina, or who died) were similar to those observed in the patients whose progress was good. There was no relation between the degree of hemorheological disturbances, and platelet dysfunction and the number of attacks of angina. Thesure results demonstrate the existence of a syndrome of blood hyperviscosity and platelet dysfunction in unstable angina. These disturbances did not seem to be related to the clinical outcome of patients or to the severity of angina.
Abstract: Blood rheological abnormalities play an important role in venous pathology as does varicose vein disease. In this study the essential microrheological parameters (hematocrit, plasma viscosity, fibrinogen, erythrocyte aggregation and deformability) were tested on 20 control subjects and 20 patients having varicose veins in the legs.The measurements were taken on samples collected at an antecubital vein, on leg veins before and after 30 minutes of stasis. Those patients having varicose veins of the lower limbs showed aggravated rheological disturbances after stasis. In the veins, where the blood flow rate is the lowest, the erythrocyte aggregation appeared as the fundamental parameter associated…with the alteration of red cell deformability and with the increase of plasma viscosity.
Abstract: Bepridil is a new calcium antagonist that was found to cause swelling and stomatocytosis of normal erythrocytes by increasing passive permeability of cations across the cell membrane. At 100 µmol/l, the drug also fully inhibited the Ca2+ -activated (Gardos) K+ channel. When normal and sickle erythrocytes were dehydrated by Ca2+ loading using the ionophore A23187, bepridil at 10–100 µmol/l had a significant protective effect against loss of filterability through pores of 5 µm diameter. Bepridil has the potential to prevent erythrocyte dehydration and sickling by blocking entry of Ca2+ , by inhibiting loss of K+ via the…Gardos channel, and by increasing passive permeability of cations from plasma.
Abstract: The changes in erythrocytes composition and hemorheological parameters are studied in myocardial infarction (MI) patients. The study shows that cholesterol, phospholipids and c/p ratio in erythrocytes are increased in MI patients when compared to that of’ normals. The individual phospholipid composition is also altered with increase of phosphatidylcholine and sphingomyelin in plasma, and phosphatidylcholine in erythrocytes. There is no significant change in protein composition except a significant decrease in sialic acid content of cell. The membrane enzymes such as Na+ , K+ ATPase and Ca2+ ,Mg2+ ATPase are decreased and there is no change in cytosolic…calmodulin stimulatory activity observed. Whole blood viscosity and osmotic fragility are increased. The deformability of erythrocytes is significantly decreased.
Abstract: The fragility of erythrocytes (RBC) from patients with acute ischemic stroke and from normal age-matched control individuals was compared in the presence of ionomycin and various calcium ion concentrations ranging from 0 to 2.5 mM after filtration through 5 µm pore diameter polycarbonate membranes at 20 cm Hg pressure. At calcium ion concentrations of 0.5, 1.0 and 1.5 mM, RBC from stroke patients hemolyzed to a greater extent than those obtained from controls. This difference is indicative of abnormal calcium ion homeostasis in RBC obtained from stroke patients. Flunarizine, a calcium ion channel blocker, significantly inhibited the degree of hemolysis…of RBC due to calcium loading in both stroke and control groups. These data are consistent with numerous reports showing that calcium ion homeostasis plays a crucial role in governing RBC mechanical properties including cellular deformability.
Abstract: RBC aggregation is studied on 60 insulin dependent diabetic patients and 61 controls by laser light reflectometry technique. This study indicated a complete REC disaggregation shear stress higher in diabetics than in controls and increasing with retinopathy intensity. Otherwise, we have shown a positive correlation between the disaggregation shear stress and fibrinogen, glycosilated haemoglobin (HbA1C ) or alpha-2 globulins levels. Aggregation was higher when diabetic erythrocytes are suspended in their own plasma than in normal plasma. On the other hand, for cells in the same suspending medium (normal or diabetic plasma, dextran solution), cross-over experiments showed that diabetic erythrocytes aggregates…more than normal erythrocytes. These results suggest that hyperaggregation in diabetics is both related to an increased protein level (fibrinogen) and to an intrinsic membrane erythrocyte abnormality. The relationship between the alteration in erythrocyte adhesiveness and retinopathy was discussed.
Abstract: A nuclepore filtration technique was developed for a clinical evaluation of the deformability of blood cells (red and white) at low shear rates. The filtration process of blood suspensions at low pressure differences was recorded continuously with a microscope-TV-video system. The time course of decreasing filtration pressure was analyzed from the video-monitor. The obtained results are as follows: 1) The relative resistance (Rr ) of the blood suspension increased in the time course of filtration. 2) When negative pressure was added, the Rr remained almost constant and its increasing rate was very slight. 3) A great difference appeared in…the Rr between normal subjects and patients a low pressure difference below around 10 mmH2 O. The Rr showed a difference before and after treating patients. 4) More than 10% WBCs could pass through the nuclepore (5µm diameter). The present nuclepore filtration method showed that the differentiation of RBC deformability at low flow rates was more obvious and sensitive, suggesting it would be useful for clinical applications.
Keywords: filtration test, relative resistance, red cell deformability, white cell plugging, low flow rate
Abstract: With the aid of multiple linear regression analysis, the depedence of whole blood viscoelasticity on different laboratory parameters was investigated. Viscoelasticity was determined by means of an oscillating capillary rheometer at a frequency of 2 Hz and an amplitude of wall shear rate of 10 l/s. The results showed, that the viscous component of viscoelasticity depends mainly on hematocrit and to a small degree on plasma viscosity. The elastic component of viscoelasticity on the other hand is influenced to a greater extent by plasma viscosity and is additionally influenced by the plasma proteins (fibrinogen, albumin, and cholesterol) and platelets. Thus,…81% of the variation found for the viscous and 75% for the elastic component of a reference population of normal donors could be explained.
Keywords: Blood viscoelasticity, oscillatory capillary rheometry, normal values, laboratory parameters, multiple linear regression
Abstract: The influence of RBC mechanical properties and aggregation on the viscoelasticity of whole blood was studied in an oscillating capillary flow. Cell membrane mechanical properties were altered by age separation into old and young RBC, by heat treatment and glutardialdehyd fixation of RBC. The altered RBC were resuspended in autologous plasma. Aggregation was increased adding different amounts of Dextran 110. The results indicate, that changes of RBC membrane elasticity mainly influence the elastic component while changes of membrane viscosity influence the viscous component of complex viscosity. Membrane mechanical effects can be discriminated from enhanced aggregation.
Abstract: Complex viscosity of whole blood in patients with arterial circulatory disorders have been determined under treatment with a Ginkgo biloba extract. The Ginkgo preparation influences the pathologically increased blood viscoelasticity, especially the elastic component. By parenteral daily infusions the viscoelasticity is decreased significantly after 5 to 10 days of treatment. By prolonged oral administration up to 3 months a marked continuous improvement of viscoelastic parameters could be observed. The latter type of response suggests the preparation’s ability to influence the erythropoietic cells and thus forming a new population with normalized hemorheological properties.
Abstract: When normal native or heparinised blood is forced under pressure through a filter with capillary sized holes, platelets aggregate during their passage through the filter which takes 8 ms. When sufficient aggregates are retained the filter blocks. The effluent blood is collected from 0–3s (first phase) and between 10–20s (second phase); the platelets are counted, and the percentage retained is calculated. Normally this is 50±12% and 66±15% respectively. With von Willebrand’s (vW) blood no blocking occurs and platelet retention in both phases is low. With EDTA blood and in the presence of some “membrane active” drugs, the first phase is…normal; retention during the second phase is, however, decreased with no blocking. The use of monoclonal antibodies shows that glycoproteins (GP) IIb/IIIa and vWf are essential for blocking, but GP Ib is not. Thus, aggregation in the first phase requires high shear, vWf and GP IIb/IIIa only, while divalent cations are essential for the second. It is proposed that high shear alone will expose and activate GPr IIb/IIIa; vWf is then essential for platelet aggregation in the filter and fibrinogen is largely irrelevant.
Abstract: Experiments were realized on conscious Wistar rats with preoccluded both vertebral and right carotid arteries. Thrombus formation was induced in the left carotid artery by applying an anodal current of 1 mA during 12 minutes. Following the left carotid obstruction by the thrombus, rats became unresponsive and lost their righting reflex. The ability of various compounds to delay the loss of the righting reflex was investigated. Heparin, prostacyclin, iloprost, the thromboxane receptor antagonist BM 13177 and naftidrofuryl exerted a significant activity, whereas acetylsalicylic acid, dipyridamole, sulfinpyrazone, and the thromboxane synthetase inhibitor, dazmegrel, were inefficient
Abstract: In diabetics, microalbuminuria reflects a multifactorial reversible glomerular dysfunction, announcing further development of overt nephropathy. This study aimes to determine whether microalbuminuria and its rise during a standardized exercise test are related to blood rheology. A cross-sectional study of 47 insulin dependent diabetics showed that impaired values of whole blood filterability (as found in 26 subjects) were associated with an increased resting microalbuminuria (21.755 ± 3.91 µg/min vs 8.125 ± 1.226, p < 0.03) whereas exercise induced rise in microalbuminuria did not differ between the two subgroups and showed no relationship with exercise-induced changes in filterability. Resting microalbuminuria correlated with…blood pressure only in the subgroup exhibiting reduced blood filterability (r = 0.549 ; p < 0.01). Preliminary results of an open study with pentoxifylline (800 mg/day during 3 months) suggest that this drug reduces resting microalbuminuria but not its exercise-induced increase. Those data might be consistent with the following working hypotheses: (a) hemorheologic disorders detectable with blood filterability measurement could impair glomerular microcirculation, increasing its sensitivity to blood pressure. Therefore, they could be an additional risk factor, as previously stated by Solerte. (b) microalbuminuria rise during exercise is not likely to be an artifact resulting from exercise-induced hemorheologic changes, but might be an improved index of abnormalities already existing at rest. (c) our findings seem to be consistent with previous reports suggesting a beneficial effect of pentoxifylline in this process. However, this latter concept requires further investigations.
Abstract: Reduced hematocrit (H) in diabetic patients with vascular complications has been found in several studies, but this fact remains uncompletely understood. In 159 type 1 diabetics we measured packed cell volume (PCV) during a complete check-up of diabetic complications. On the whole sample, PCV was lower in the 98 patients exhibiting detectable complications (40.511 %± 0.483 vs ± 42.211 ± 0.541, p < 0.03) when compared to the 61 others. However when studying separately men and women, the most significant result was found in men with macroangiopathy, who had a lowered PCV (38.4 ± 0.358 vs 44.33 ± 0.667 p…< 0.01), while in women this difference did not reach the significance. Neuropathy, retinopathy or microalbuminuria alone were not associated with significantly reduced PCV. The lowest values were found in subjects with overt nephropathy, who must be considered separately since moderate anemia could result from chronic renal failure. In this study, H lowering seems to be multifactorial and is mainly found in macroangiopathy. Possible explanations for this finding are discussed.