Clinical Hemorheology and Microcirculation - Volume 13, issue 1
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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: This study concerns the effect of intravenous thrombolysis in patients suffering from Peripheral Obliterative Arterial Disease (POAD) at the stage of “Accelerated Limb Ischemia” (ALI). In a previous study on 17 patients, where Streptokinase was employed, there was complete or partial reopening of obstructed vessels in 5 cases and an improvement of clinical conditions in 10 cases. Unfortunately, 6 (35%) patients experienced significant side effects. Subsequently, in 9 POAD patients, we employed rt-PA at the dosage of 100 mg infused i.v. over a period of 4–6 hours. This treatment showed a clinical and instrumental improvement in a high percentage of…patients without any important side effects. The effect of the treatment was examined by means of Doppler ultrasound, strain gauge plethysmography and Transcutaneous oxygen tension (TcPO2). Haemorheological and fibrinolytic parameters were also assessed and no important changes were observed either in blood or plasma viscosity in spite of the reduction of fibrinogen concentration (especially in the Streptokinase group) and the improvement of leg perfusion. Explanation of this aspect was sought through an “in vitro” study: here rt-PA was added to blood samples so as to obtain a more definite fibrinolysis. Before and after the addition of rt-PA, blood and plasma viscosity, fibrinogen, FDP and FDP-E were examined. The results illustrated that the reduction of plasma and blood viscosity was not as significant as the disappearance of fibrinogen might have led us to expect and showed a marked increase of fibrinogenolytic products (FDP and FDP-E). These findings reinforce the working hypothesis stating that fibrino(geno)lytic products can affect plasma and blood viscosity as much as the intact fibrinogen molecule does. So it was concluded that the beneficial results obtained with fibrinolytic agents, in patient with POAD at the ALI stage, are due to the reopening of vessels and not to the rheological effect.
Abstract: We measured neutrophil filtrability at different temperatures and pH levels using a filtration method which provided a model system that is regarded to reflect conditions in the microcirculation. Neutrophil filtrability decreased as temperature fell (range: 40 to 4°C), but did not change with pH (range: 6.8 to 7.6). The decreased filtrability induced by cell cooling to 4°C was completely reversed by cell rewarming to 37°C and was also suppressed by the addition of cytochalasin B, which disrupts cellular actin filaments. Thus, neutrophil filtrability may be reduced by hypothermia, this reduction being, in part, to structural changes in cytoskeletal actin organization.…These findings suggest that temperature setting is important in the measurement of neutrophil filtrability.
Abstract: In a group of 22 subjects with essential hypertension we evaluated the red cell filterability and aggregation, the erythrocyte membrane fluidity and red cell membrane transverse fluidity gradient. We also evaluated the total red cell Ca2+ content, the red cell cytosolic free Ca2+ content, the red cell membrane cholesterol/phospholipid ratio and the red cell membrane individual phospholipids. From our results, it is evident that the macrorheological as well as the microrheological determinants discriminate normals from hypertensives. From our data, a significant increase of the total and cytosolic red cell Ca2+ content is evident in hypertension. In hypertensives, the evaluation of…the red cell lipid parameters shows that only the CL/PL ratio plays a discriminant role. The study of correlations between the microrheological determinants and red cell metabolic parameters shows interesting findings.
Keywords: essential hypertension, rheological determinants, total and cytosolic red cell calcium content, erythrocyte membrane lipids
Abstract: Lipid A is responsible for the endotoxic activities. The effect of different lipid A concentrations and incubation times on red blood cell (RBC) deformation was studied by means of a rheoscope. Lipid A concentrations of 10 and 100 μg/ml decreased RBC deformability by 41% and 46%, respectively, after 20 min of incubation. After 1 h, RBC deformability nearly reached preincubation values. Lipid A binding to RBC membranes (passive hemolysis test) was similar after 30 and 60 min incubation. This suggests that lipid A binding to RBC membrane does not change during this time, but that lipid A is inserted into…the membrane, thereby improving RBC deformability.
Abstract: Erythrocyte filterability and aggregation were measured in two separate groups of psoriasis patients, one treated with cyclosporin-A (CsA; 2 mg/kg daily) and the second with topical preparations only. Erythrocyte deformability indexes were significantly higher in both groups of patients in comparison with a healthy control group. Erythrocyte aggregation indexes were decreased significantly in psoriasis patients, however the indexes in the group treated with CsA were closer to the control values. These findings can be explained on the basis of biochemical changes in red blood cells observed in psoriasis patients, but the pathophysiological significance of hemorheological alterations remains unclear.
Abstract: The deformability of erythrocytes from 30 healthy controls and from 10 patients with pyruvate kinase (PK) deficiency in different states of red blood cell (RBC) maturation has been determined by cell filtration through polycarbonate sieves. The deformability of the whole RBC population from patients with a mild clinical course was with a flow rate of 16–20 μl/sec markedly decreased, compared to the controls (54 ± 4μl/sec). Red blood cells from patients with severe degree of hemolysis showed even lower flow rates (4–8μl/sec) depending on the counts of reticulocytes. Separation of the different RBC-fractions was obtained by density gradient centrifugation.…Normal “young” erythrocytes are more deformable than “old” erythrocytes showing in filtration experiments flow rates between 60–65 μl/sec, compared to the old cells, which exhibited a velocity of 40–45 μl/sec. Flow rates of the reticulocytes from all patients, independent from their clinical condition, had a value of 5–10 μl/sec. The flow rates of their “old” cells, however, very well agree with the degree of hemolysis. In case of mild clinical course the flow rates of the “old” cells were 15–45μl/sec whereas in case of severe disease the flow rates were even more decreased (5–15μl/sec). The filtration rate of the whole red blood cell population apparently can be regarded as the sum of the filtration rates of the single fractions and the low total filtration rate of cells from patients with PK deficiency is caused mainly by the rigidity of reticulocytes present in their whole blood. The results of these rheological investigations support earlier kinetic and electrophoretic studies with enzymes from patients suffering from PK deficiency, where could be demonstrated that reticulocytes from normal controls and from patients with PK deficiency showed no deviating behaviour, whereas the erythrocytes do deviate, thus suggesting a perturbation of their maturation process.
Keywords: Pyruvate kinase deficiency, cell separation, red blood cell deformability, energy metabolism
Abstract: Red blood cell (RBC) deformability was studied by means of a rheoscope and RBC membrane rigidity (i.e. membrane extensional elastic modulus, μe ) was measured by using a flow channel in seven children and adolescents (9 to 17 years) with chronic renal failure undergoing regular hemodialysis. μe was 6.34±1.28x10−6 N/m in the uremic patients and 4.48±0.55×10−6 N/m in a control group of six healthy children (P<0.001). RBC deformation in the rheoscope (shear stress of 0.7 Pa) was 0.14±0.03 in the uremic patients and 0.19±0.02 in the controls (p<0.01). At a shear stress of 3 Pa, there was…no significant difference between the patients and the controls. These results indicate that chronic renal failure is associated with increased RBC membrane rigidity and decreased RBC deformability at low shear.
Abstract: The initial flow rate of diluted blood, from patients with intermittent claudication, can be used to calculate the average flow properties of a combined population of lymphocytes and granulocytes. The transit time for the flowing leukocytes, calculated in this way, is close to that determined from the flow rate of suspensions of unfractionated leukocytes. The isolation and purification of leukocytes is therefore not a prerequisite to the investigation of their filterability in this group of patients. The number and transit time for flowing leukocytes is higher in the patient group compared to normals, and the variation in the rate of…flow of diluted blood through 5 μm membranes is attributable to differences in both the concentration and the flow properties of the participating leukocytes. Small variations in red cell transit time or platelet count are not reflected in the measured flow rate of diluted blood.
Abstract: On a randomly selected western Sicily population sample (Casteldaccia Study: 600 subjects; 300 males and 300 females) of an age range from 40 to 79 years, were determined: Haematocrit (Htc) , blood viscosity, plasma viscosity, filterability of whole blood and fibrinogen. Participation was 97%, being 582 subjects (M = 287, F = 295). All the parameters measured showed a progressive increase with age and significant differences were found between male and female subjects: Htc and blood viscosity were higher in male subjects (p < 0.01), while plasma viscosity, whole blood filterability and fibrinogen were higher in female subjects (p <…0.05). In subjects who smoke, compared to non-smokers, all the haemorheological variables had significantly higher values (p < 0.005). Analysis of simple linear regressions showed a positive correlation between Htc and blood viscosity (r = 0.80), between plasma viscosity and fibrinogen (r = 0.81), between filterability and fibrinogen (r = 0.59) and between plasma viscosity and filterability (r = 0.64). Fibrinogen, plasma viscosity and filterability of whole blood were positively correlated with age (r = 0.37, r = 0.46, r = 0.41 respectively). The authors conclude that the measurement of haemorheological variables is a necessary for the assessment of cardiovascular risk, especially in subjects in age range 40–79 years.