Clinical Hemorheology and Microcirculation - Volume 7, 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: The effect of temperature on the viscosity characteristics of erythrocytes suspended in plasma, serum, buffer and fibrinogen or dextran solutions and of the suspending phases have been compared. All the suspending phases obey the relationship η = A e c / T where η is the viscosity, T temperature (°K) and A and c are constants. The value of A varies with solute concentration but that of c is common to all of these solutions. The cell suspensions obey a similar relationship, but the value of…c increases abruptly below about 22°C suggesting that a membrane phase transition occurs at about that temperature. The data indicate that rouleaux formation is temperature dependent whether induced by dextran, fibrinogen or serum proteins. However, they also indicate that dextran has a mode of interaction with the erythrocyte which differs from that of the proteins.
Abstract: Seven patients suffering from sickle cell disease were treated over a period of eight weeks with 30–36 mg/kg pentoxifylline. Rheologic properties of erythrocytes from these patients were studied before and after treatment by cell filtration through polycarbonate filters. Erythrocytes of the patients passed through the filter pores more slowly than cells from healthy controls. Oxygen saturation leads to an increased filterability of the erythrocytes of the patients. After in vivo treatment with pentoxifylline the filtration rate was significantly improved without oxygen saturation. The number of sickled shaped cells was monitored before and during treatment with pentoxifylline. As a…result of treatment improvement in filterability was associated with a decrease in irreversibly sickled cells.
Abstract: Hypertension data has been classified into three groups depending on duration of hypertension and response to treatment. Haemorheological parameters studied include, plasma viscosity, whole blood viscosity, red cell aggregation, red cell deformability and haematocrit. In controlled hypertensives all the haemorheological parameters were similar to normal group. In uncontrolled hypertensives (under treatment but not fully controlled); plasma viscosity, whole blood viscosity at high shear rate, red cell aggregation and red cell deformability were significantly different from the normals. In freshly detected hypertensives the haemorheological abnormalities were similar to uncontrolled hypertensives except for red cell deformability which is not significantly altered. Haematocrit…is unaffected in all the groups.
Abstract: In the People’s Republic of China a number of herbal extracts are known to be vasoactive and are prescribed to promote blood circulation and relieve hemostasis. The object of this study was to examine whether the effects of three particular extracts, derived originally from the herbs Anisodus tanguticus, Chuanxiong rhizome and Injectio salvia miltiorrhizae , are linked to alterations in erythrocyte deformability. Erythrocytes from 16 normal donors were incubated for 1 hour at 37.5°C in solutions of extracts of these herbs at various concentrations. Subsequently, dilute suspensions of the exposed cells and paired, unexposed controls were subjected to graded…levels of shear stress in a rheoscope. Two indices of deformability derived from rheoscopic observations were the shear-induced elongation of freely suspended, steadily tank-treading cells and the rate of transient shape recovery following abrupt cessation of shear. The results indicate significant increases (10 to 20%) in extensibility under an applied shear stress of 40 dyn/cm2 and significantly faster (7 to 25%) shape recovery in cells exposed to the herbal solutions. A separate series of experiments on normal erythrocytes demonstrated that the herbal solutions produced no significant changes in mean cellular volume, thus ruling out increases in cell surface-to-volume ratio as a basis for deformability enhancement. Hence, the observed enhancement appears to be attributable to changes in membrane mechanical properties.
Keywords: Erythrocyte deformability, Chinese medicinal herbs, Rheoscope, Anisodus tanguticus, Chanxiong rhizome, Injectio salvia miltiorrhizae
Abstract: Metformin was added to blood samples taken from 10 patients with type-IIb diabetes, giving final contrations of 1,3, and 8 mg metformin/l. The yield shear stress of the blood, the erythrocyte rigidity and aggregration, and the plasma viscosity and fibrinogen concentration were determined under the influence of metformin in comparison with untreated control samples. Concentrations of 1 and 3 mg metformin/l brought about a distinct and dose-dependent reduction in the aggregration tendency of the erythrocytes, and to a smaller extent in their deformability, which led to a decrease in the yield shear stress. These effects could no longer be…observed at a concentration of 8 mg/l. There was no apparent effect on plasma viscosity. This indicates the possibility that metformin, in addition to its antihyperglycaemic action, also has favourable haemorheological properties.
Abstract: The effects of fat emulsions on adult and neonatal blood viscosity were investigated under controlled conditions in vitro over a wide range of shear rates from 0.35 sec−1 to 1500 sec−1 . A 20% fat emulsion (Liposyn), currently used for parenteral nutrition, was added to anticoagulated blood samples at a concentration approximating the highest blood levels expected clinically (0.01 ml 20% Liposyn/ml blood) and at a concentration four times greater. Apparent viscosities of these and control samples without added emulsion were measured at constant hematocrit and plasma protein concentration at 37°C in order to determine the types of…interactions that occurred between blood constituents and the lipids. There was no difference found in plasma viscosity, or in whole blood apparent viscosity, between control samples and blood containing the lower concentration of lipid emulsion. Blood containing the higher concentration (0.04 ml 20% Liposyn/ml) of fat emulsion showed a 2–25% increase in whole blood apparent viscosity, with the magnitude of the increase greatest at low shear rates, and also greater in neonatal blood compared to adult blood. In addition, plasma viscosity was also increased at the high lipid dose by an average of 9% and 17% in adult and neonatal blood, respectively, independent of shear rate. Mechanistic analyses of the observed increases suggested that the majority of the whole blood viscosity increase was due to the plasma viscosity increase rather than to large changes in red blood cell aggregation. These viscosity results indicate that although very high doses of lipid emulsions are capable of altering plasma and whole blood viscosity in adults and neonates, the effect within the range of physiologic shear rates is small, and the usual doses of lipid emulsions used clinically are not likely to cause significant alterations in blood viscosity under conditions of normal flow.
Abstract: To improve the reproducibility of filtration method for determination of erythrocyte deformability, a newly developed nickel mesh was examined by scanning electron microscopy. Nickel mesh provides a more accurate geometry and higher reproducibility than does polycarbonate filter. This study suggests that nickel mesh can be useful in laboratory and clinical investigations of the erythrocyte deformability.