Clinical Hemorheology and Microcirculation - Volume 13, issue 6
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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: Pre - eclampsia is the development of hypertension and proteinuria after the 20th week of gestation. The most common causes of increased peripheral resistance are vasoconstriction and hemoconcentration with plasma volume contraction. Additional rheological parameters are increased red blood cell aggregation and impaired erythrocyte deformability. Preeclamptic patients showed a significantly reduced cardiac output and central venous pressure compared with normal pregnant women. It has already been shown in the studies by Garn et al. (2) and also in subsequent studies Murphy et al. (15) and Knottnerus et al (12) that a strong correlation exists between newborn weight and plasma…volume. Other authors (4,16) conclude that plasma volume contraction may plays an even larger role than vasoconstriction in the pathogenesis of the fetal growth retardation that often accompanies maternal hypertension. This view is supported by the finding that hypertension and perinatal complications can be reduced in some pregnant women by the administration of oncotic solutions (i.e. hydroxyethyl-starch) that expand plasma volume.
Abstract: In a double - blind randomized study 12 pregnant patients with hemoconcentration (average hemoglobin higher than 13 g/dl during the second trimester, initial hematocrit above 38%) and a fetal aortal resistance-index higher than 0.75 received either 500 ml hydroxyethylstarch (HES) or 500 ml 0.9% NaCl. Additionally all women received 500 ml 0.9% NaCl. Resistance Indices from waveforms in both the fetal aorta and the uterine arteries showed a reduction during HES - hemodilution while treatment with NaCl achieved no corresponding effect. One possible explanation may be the red cell aggregation-inhibition and plasma viscosity - reduction of hydroxyethylstarch.
Keywords: Hemodilution, Hydroxyethylstarch, Doppler-Ultrasound, Resistance Indices
Abstract: Previous comparative studies of plasma fibrinogen levels in blacks and whites in Africa have yielded variable results, with some researchers reporting no significant difference between the two groups, while others have reported higher mean plasma fibrinogen levels in blacks. This present study compares plasma fibrinogen levels in healthy, urban black and white male Zimbabwean blood donors. Our results show significantly higher (p<0.005) plasma fibrinogen levels in blacks (3.05±0.18) compared to whites (2.43±0.13). The blacks also showed greater variability in their plasma fibrinogen levels.
Abstract: Tests of erythrocyte rheology are sensitive to variables in the pre-analytical, analytical and post-analytical phases of the test process. Elimination or standardization of these variables is essential for good quality control and guidelines on the standardization of rheological tests have been prepared by the Expert Panel on Blood Rheology of the International Council for Standardization in Haematology. A further step to improving quality control is the development of rheological control preparations that are used whenever tests of erythrocyte rheology are performed. Candidate control preparations, and their potential contribution to quality assurance of rheological testing, are reviewed.
Keywords: Rheology, erythrocyte deformability, quality control
Abstract: Background: Research findings in clinical hemorheology must be published in the optimum way to keep medical research and practice currently informed. Objective: Critical presentation of current possibilities for publication. Results: Hemorheology supplies results which are of interest to many clinical fields. These results include: diagnostic questions connected in particular with clinical laboratories and blood transfusion centres; pathophysiological problems; the fields of epidemiology and prognosis; the most important fields of prophylaxis and therapy in all branches of medicine and surgery; pharmacology and drug research. Therefore, a wide spectrum must be covered by publication. It has to reach the medical…practitioner, the laboratory doctor, the pharmacologist, and the industrial partner in diagnosis and therapy. The protection of a high, scientific standard is the main duty of the inpendent journal. The editorial policy of the international journal “Clinical Hemorheology” is presented in its actual form and future development is discussed. Conclusion: Hemorheological publications are an essential means to present and spread this science. Quality control is based on the independence and international competence of a publisher and on the peer review policy of a multidisciplinary editorial board.
Abstract: The plasma levels of thromboxane B2 (TXB2 ) and 6-keto prostaglandin F-1α (6-PGF), stable metabolites of thromboxane A2 and prostacyclin respectively, were measured in 23 patients with coronary heart disease (CHD) and 20 healthy subjects who served as controls. The receptor density of glycoprotein (GP) IIb-IIIa complex was determined by an indirect inhibition assay. The mean levels of both TXB2 and 6-PGF were elevated in patients with CHD as compared with controls, the rise being statistically significant in case of 6-PGF (p<0.02), probably resulting from increased biosynthesis of prostacyclin. The receptor density of GP IIb-IIIa complex was…enhanced in patients with CHD (p<0.0001). There was a statistically significant positive correlation between TXB2 and receptor density of GP IIb-IIIa in controls (p<0.05), probably indicating their pro-aggregator roles.
Abstract: Erythrocyte (RBC) deformability is one of the major determinants of the ability of the RBC to pass repeatedly through the microcirculation as it influences the tissue oxygenation and the life span of the RBC. It is well known that a decrease in RBC deformability leads to some pathologies. The purpose of this study was to measure the rigidity (the inverse of the RBC deformability) of RBC from patients with Myelodysplastic (MDS) and β-Thalassemic (ThS) Syndromes in comparison with the normal ones, as determined by their filterability. Furthermore these results were compared with those obtained by the micropipette method.…The filtration measurements were made with a filtration device called Hemorheometer, based on the initial flow rate principle. In these experiments the rigidity index (IR) of 23 samples from patients with MDS (in different subtypes) of 16 samples from patients with ThS (homozygous and heterozygous) and of 10 healthy subjects was measured. From these findings, it is concluded that the mean value of IR is very significantly increased in patients with MDS and ThS as compared with healthy individuals (p<0.01). This finding correlates well with previous studies, where the deformability of the RBC membrane in patients with the same diseases was measured with the micropipette method. In those studies the elastic shear modulus, μ, which determines the rigidity of RBC membrane, was very significantly increased in all patients. Comparison of these findings suggests a possible relationship between IR and μ, which in the reported case is: IR = 3.77 + 1.165μ (r = 0.9314, p-value = 0.001).
Abstract: Trypsin and neuraminidase decrease the surface charge of red blood cells (RBC) and should, therefore, increase red cell aggregation (RCA). To assess the reliability of the Myrenne aggregometer to detect extremely strong RCA, RBC from normal adults were treated with neuraminidase or trypsin in vitro. RBC surface charge was estimated by partitioning of RBC in a two phase system containing dextran and polyethyleneglycol. RBC aggregation was studied by means of a Myrenne aggregometer and by microscopic observation in a rheoscope. RBC partition coefficient (i.e. surface charge) was 89% for normal RBC, 34% for trypsin and 5% for neuraminidase treated RBC.…RCA in the Myrenne aggregometer increased markedly with trypsin, but tended to decrease with neuraminidase treatment. Observation of RCA in the rheoscope showed that neuraminidase caused strong RBC aggregation and that dispersion of RBC aggregates was incomplete even at high shear. We conclude that studies of RCA should always include microscopic observation.
Abstract: Preoperative hemodilution can be used to save blood transfusion during total hip replacement. However, plasma substitutes do not show similar rheological properties. We have carried out a randomized study to compare the hemorheological changes induced by two artificial colloids: a 6% hydroxyethylstarch 200/0.62 (HES) versus a 6% dextran 60. Eleven patients in each group were infused with 20 mL/kg of either substitute, just after spinal anesthesia for total hip replacement. Whereas the dilutional effect was similar in the two groups with a decrease in the hematocrit to 0.30 L/L, significant differences were observed concerning the hemorheological parameters. In the dextran…group, the plasma and the whole blood viscosities were increased until hour 24 while they were slightly decreased in the RES group. The erythrocyte aggregation was increased in the dextran group, but was decreased in the RES group until hour 24. The favourable effect of HES on blood fluidity persisted at day 7, with a slighter postoperative rise of the fibrinogen. We conclude that 6% HES 200/0.62 improves the hemorheological parameters better than 6% dextran 60, and can reduce the postoperative inflammatory reaction.
Abstract: Erythrocyte deformability can be measured as filterability through a polycarbonate filter. To evaluate the influence of variations in filtration pressures the present study was performed as filtration of red cell suspensions with a pore size of 5 um at constant negative pressures of −10, −20, −30, −40 and −50 mm H2 O in the St. George's Filtrometer. Filtration parameters were expressed as passage time, flow rate, flow resistance, initial relative filtration rate (IrFR) , red cell transit time (RCTT) and clogging particles (CP). Passage time was decreased and flow rate was increased significantly at all filtration pressures compared to preceding…pressure level (p<0.001). In the pressure range −10 to −30 mm H2 O flow resistance decresed significantly (p<0.001) , but was almost constant in the range −30 to −50 mm H2 O. Also IrFR and RCTT showed a significantly greater change (p<0.001) when the pressure was increased from −10 to −20 mm H2 O compared to the same pressure change in the range −30 to −50 mm H2 O. CP varied more with pressure, but the greatest change was found in the range −10 to −20 mm H2 O. Variations of MCV within the normal range were associated with changes in passage time, flow resistance and CP in the pressure range −20 to −50 mm H2 O. It is concluded that the filtration pressure is an important factor in studies on blood cell filterability. For the St. George's Filtrometer the optimal pressure range seems to be −30 to −50 mm H2 O.
Keywords: Erythrocyte filterability, filtration test, stress factors, filtration pressure, wall shear stress, mean corpuscular volume, mean corpuscular hemoglobin concentration