Clinical Hemorheology and Microcirculation - Volume 8, issue 3-4
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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: In a group of subjects with chronic renal failure (CRF) not yet in need of dialysis therapy we evaluated macro and microrheological determinants. From the obtained data it is evident that the whole-blood filterability as well as red cell aggregation discriminate normals from subjects with CRF. Same behaviour is present regarding the erythrocyte membrane fluidity. This parameter evaluated using fluorescence technique, distinguishes clearly normals from subjects with CRF. The datum regarding the red cell membrane fluidity suggests that in these patients a membrane structural alteration is present. This alteration seems dependent on the oxidative and lipidic metabolism that is altered…in this pathology.
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Abstract: Oxidative sensitivity, measured by a modified ascorbate cyanide test, GSH and 51 Cr-RBC cytotoxicity, was abnormal before the haemodialysis. This increases after 30 min. dialysis, just behind the leukocytes drop. Biocompatible dialysis membranes do attenuate this phenomenon. All are indicative of RBC scavenger function against toxic oxygen radical production in dialysis patients. Despite this abnormality, erythrocyte deformability was completely normal.
Abstract: The sensitivity of the Single Erythrocyte Rigidometer (SER) has been improved and a new software program allows us the detailed analysis of subsequent passages. The flow of a single RBC can be differentiated into entry, transit, and exit phase. Application of stress models on RBC filtration resulted in pronounced effects of the entrance into the pore. Filtration of white blood cells increased the driving pressure gradient by a factor of more than 30 compared to RBC filtration.
Abstract: In order to study the concept of RBC sub-population deformability. we have developed a new system called the Cell Transit Analyser (CTA) which measures the electrical conductance change produced by cells travelling through individual cylindrical micropores. The cell’s transit time through the pore can be determined. This computer-based device provides both the mean transit time T for the entire cell population and the distribution of transit times for a large number (e.g. 2000) of cells. Initial experiments were performed with a large-scale electrical model in order to allow analysis of the electrical resistance signals. Experiments with red cells were designed…to evaluate the flow behavior of both normal cells and cells with abnormal mechanical properties (i.e. RBCs whose mechanical properties were artificially altered and cells with significant rheological abnormalities such as sickle cells). For both control and “rheologicaly abnormal” red cells, a skew distribution of transit time towards longer transit times was observed.
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Keywords: red blood cell, deformability, filtration, transit time
Abstract: Among the factors affecting oxygen supply to the tissues, red blood cells’ transit time through the microcirculation occupies an important place. Now, this transit time depends on two essential parameters: 1- the erythrocytes’ rheological properties; 2- the haemodynamic conditions existing locally in vivo. Therefore, lonely measurements of red blood cells’ deformability by in vitro methods do not allow a complete survey of microcirculatory status. We describe a new non invasive method providing quantitative characteristics of the distribution of red blood cells’ transit time through the cerebral microcirculation. This technique has been used in a clinical trial and has given objective…criteria of Nafronyl’s (LIPHA Company - France) efficacy in elderly’s vascular dementia.
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Keywords: Red cell transit time, cerebral microcirculation, red cell rheology, oxygen supply
Abstract: Intracellular dehydration is a feature of older erythrocytes which thus have a higher mean cell haemoglobin concentration and can be separated by density-gradient fractionation. Studies of fractionated erythrocytes have demonstrated rheological and haematological heterogeneity with the denser cells showing multiple rheological abnormalities. Sickle cells are particularly heterogeneous with the denser sub-populations having a dominant rheological effect. Rheological methods should take this heterogeneity into account by analysis of erythrocyte sub-populations after density-gradient fractionation or by using instruments that measure the rheology of single cells. Such techniques are of particular importance in studies of the pathogenesis and treatment of sickle-cell disease.
Abstract: The main studies in Clinical Haemorheology have been performed on the red cell. However, rheologists and clinicians recently began to analyze the leukocyte behaviour in microcirculation. Our study carried out the evaluation of the leukocyte deformation and the effects of an hemorheological drug (pentoxifylline) by a simple filtration method. Two subpopulations were taken into account : mononuclears and granulocytes. Different physical factors (pressure, number of cells, pore diameter) were assessed in order to find out the optimum conditions for studying the leukocyte filterability. The granulocyte population seems to be more rigid (Igranu = 3.33 ± 0.85 N = 10)…as compared to the monocyte population (Imono = 3.01 ± 0.74 N = 9) for 3 000 G/L. The incubation of these fractions with pentoxifylline (7.10−4 M) for one or two hours at 37° C showed that pentoxifylline does improve the leukocyte filterability significantly for an average of 17 %.
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Abstract: Erythrocyte Deformability (ED) was investigated by a Cell Transit-time Analyser (CTA) in three populations: elderly subjects, liver diseases patients and controls. Different conditions of measures were evaluated: anticoagulants (EDTA and heparin), buffers (PBS and tris), temperatures (25° C and 37° C), and different pressures. The CTA analysed the deformability of individual cell passing through 5 um pores of a polycarbonate filter (Oligopore) under a low hydrostatic pressure. This method showed that E.D. was lower in elderly and in liver diseases groups than in the control group. Several fractions of less deformable red cells, as regard to their transit-times through the filter,…were detected by the CTA. By contrast, red cells from controls group didn’t present these subpopulations.
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Keywords: Erythrocyte Deformability, CTA, transit time, subpopulations
Abstract: Erythrocyte deformability (E.D.) was investigated by two filtration techniques: the Hanss’hemorheometer and the Cell Transit Time Analyzer (CTA) in elderly subjects and in subjects with liver diseases. Unlike the hemorheometer, the CTA technique is in a position to analyze the deformability of each red cell passing through 5 µm pores of a polycarbonate filter (Oligopore) under a low hydrostatic pressure. Both methods showed that E.D. was lower in the elderly group and in the liver diseases group than in the control group. Another characteristic of the CTA is to detect a few fractions of less deformable red cells.
Keywords: CTA, Erythrocyte Deformability, red cell subpopulations
Abstract: Two community studies were set up to examine among other objectives, laboratory tests predictive of ischaemic heart disease (IHD). Over 2,000 middle-aged men were examined in each community in South Wales (Caerphilly) and the West of England (Speedwell, Bristol). Plasma viscosity was associated with age, smoking habit and existing cases of IHD. Preliminary incidence data indicated that plasma viscosity was significantly increased in subjects who died subsequently from IHD over a four year period of follow-up. Whole blood viscosity measurements were made on a systematic sub-sample of the Caerphilly population. Preliminary results from the first 297 men showed significant associations…between existing cases of IHD and certain calculated indices from the ‘rheological profiles’ carried out for each subject. These analyses provide encouragement for this technique but analysis of larger data sets which are being collected is required to clarify these relationships.
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Abstract: As part of a population survey for cardiovascular risk factors, plasma viscosity and hemoglobin were measured in 4022 individuals aged 25 – 64 years. The results show that there is no age- or sex-dependency of plasma viscosity in healthy participants; while hemoglobin shows the well known sex difference. In contrast, plasma viscosity increases with age in the total population. Plasma viscosity in women is elevated in hypercholesterolemia and in obesity. In men it is increased in hypercholesterolemia, untreated hypertension and in smoking participants. Hemoglobin is elevated in women who smoke and is not increased in the presence of any risk…factor in men. The results confirm clinical trials showing hemorheological deficits in cardiovascular risk factors. Thus the hypothesis of a link between blood rheology and cardiovascular risk is strengthened.
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Abstract: Blood viscosity, plasma viscosity, haematocrit and fibrinogen were measured in 1260 men and women aged 25–64 years in the West of Scotland and related to cardiovascular ar risk factors. Blood viscosity and haematocrit were higher in men than women; there was no sex difference in plasma viscosity or fibrinogen. In both sexes, blood viscosity increased with smoking, age, blood pressure, body mass index and serum total cholesterol. In general, these correlations were stronger for blood viscosity than for haematocrit, plasma viscosity or fibrinogen. The data are consistent with a role for blood viscosity in cardiovascular disease, and will be related…to prevalent and incident disease.
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Abstract: Menopause-related changes in hemorheological parameters were assessed in 129 healthy women aged 45–54 years undergoing a routine health examination. Menopausal status was confirmed by hormonal measurements. There were no significant differences in blood cell filterability, erythrocytes rigidity index and haematocrit between premenopausal and postmenopausal women. However, postmenopausal women had higher plasma viscosity than premenopausal women and the increase in plasma viscosity could not be explained by a weak but not significant rise in fibrinogen in postmenopausal women. These results suggest that menopausal changes in blood rheology are due to plasma viscosity rather than to blood cell filterability or red cell…deformability and may somewhat contribute to the increased risk of coronary heart disease in postmenopausal women.
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