Clinical Hemorheology and Microcirculation - Volume 16, 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: Red blood cells (RBC), previously fixed with glutaraldehyde, adhere to glass slides coated with fibrinogen. The RBC solution is injected in a diffusion cell where the RBC's settle on the horizontal glass surface, which is observed with an inverted optical microscope. This experiment is repeated for a series of RBC concentrations in the solution. The relative surface covered by the RBC's, as well as the variance of this surface coverage, is obtained for each concentration by means of image processing. In order to model the process, the RBC's are approximated by disks or spheres. A simulation code was developed on…the basis of the “Random Sequential Adsorption” (RSA) model. Usually, no overlap is allowed, and the particles, once adsorbed, stay permanently fixed in place. Here, the model is extended to account for possible overlap between the RBC's. The surface covered, estimated by simulation, as a function of the number of particles deposited on the surface, shows a clear deviation from a linear relation if overlaps are taken into account; this trend is supported by the experimental data. In the same way, the coverage fluctuation is best reproduced if overlaps are allowed. On the other hand, somewhat surprisingly, a model taking into account both the random diffusion of the RBC's and the gravitational force they experience, but assuming no overlaps, describes also quite reasonably the experimental coverage fluctuation.
Abstract: One of the mechanical factors affecting significantly RBC aggregation, and consequently blood flow, is the oscillatory character of flow. This fact follows from the measurement of RBC aggregation and rheological behaviour of blood in both steady shearing flow and steady shearing flow with superposed oscillations. At the comparable flow conditions, RBC are more disaggregated in oscillatory flow due to oscillations then in steady shearing flow. Consequently, the viscous character of blood rheological behaviour in oscillatory flow does not change so significantly with decreasing intensity of flow as shear viscosity and the effect of elasticity on blood flow is nearly eliminated.…It suggests that the significance of various changes in RBC aggregability of different origin may be substantially suppressed in oscillatory flow of blood in spite of the decisive effect of the aggregability changes on blood shear viscosity and steady shearing flow.
Keywords: Kinetics ofRBC aggregation, Blood rheology in oscillatory flow
Abstract: Activated leukocytes generate oxygen free radicals and cause injury in a variety of surrounding cells. Red blood cells (RBC) are among the most susceptible cells to this injury. Deformability, lipid peroxidation and membrane proteins were investigated in RBC after incubation with activated granulocytes (2 hours, at 37°C), obtained from guinea pigs with experimental sepsis. A second group of experiments was conducted with non-activated granulocytes isolated from blood of healthy guinea pigs. RBC transit time through 5 μm pores measured by a cell transit analyzer was 3.25 ± 0.12 msec and 2.86± 0.02 msec in the suspensions containing activated and non-activated…granulocytes, respectively (p<0.05). Addition of superoxide dismutase (SOD) (20 Ilg/ml) and catalase (40 μg/ml) inhibited the effect of activated granulocytes on RBC deformability. Lipid peroxidation was also increased under the influence of activated granulocytes (31.50 ± 3.36 nmol/grHb versus 20.02 ± 2.97 nmol/grHb); SOD failed to prevent this increment, while catalase was found to be effective. A widening of Band 1 (spectrin) was observed in SDS-PAGE electrophoresis of membrane proteins of RBC incubated with activated granulocytes, indicating spectrin-hemoglobin crosslinking. This alteration was prevented by both SOD and catalase, as in the case of transit time. The superoxide radical seems to be responsible for the membrane protein and mechanical alterations, while lipid peroxidation was induced by a different oxidative mechanism.
Keywords: Red blood cell deformability, leukocyte activation, oxidant stress
Abstract: We studied the behaviour of plasma endothelin levels in 7 elderly patients with critical limb ischemia, during iloprost infusion with the aim to clarify both the interaction among various vasoactive endothelial substances and the endothelin importance in atherosclerotic disease development. Iloprost (diluted with saline solution in a concentration of 200ng/ml) was administered intravenously, from 30 to 40 ml/h, for six hours/day and for 4 weeks. Plasma endothelin concentration was determined on the 4th day of treatment at time intervals of 0, 2, 4, 6 and 8 hours: i.e. before the beginning of the infusion, then every two hours till the…sixth hour and two hours after the end of iloprost infusion. The control group was composed by 7 subjects matched for age affected by peripheral obliterant arterial disease at the I and II Fontaine stage: only saline solution was administered to them. The mean ± SD plasma endothelin level of patients in iloprost infusion was 5.40 ± 1.23 pg/ml at T0, 4.24 ± 0.72 pg/ml at the second hour, 4.22 ± 0.74 pg/ml at the fourth hour, 4.24 ± 0.22 pg/ml at the sixth hour and 4.49 ± 0.58 pg/ml at eighth hour. The difference between basal endothelin level and that of the second, fourth and sixth hour was statistically significant (p<0.05) while that of the eighth hour was not. In the control group the means ± SD plasma endothelin levels were respectively 5.23 ± 0.55 pg/ml, 4.88 ± 1.39 pg/ml, 5.44 ± 1.51 pg/ml, 5.10 ± 0.86 pg/ml and 5.60 ± 1.64 pg/ml at the same intervals The difference between the basal endothelin level and the successive ones was not statistically different. In atherosclerosis the endothelial contracting factors become more important whereas the formation and/or effects of the relaxing factors are impaired. Iloprost infusion, therefore, may restore physiological equilibrium among various vasoactive substances, so that tissue perfusion is further improved.
Abstract: A Couette device was used for the examination of the flow behaviour exhibited by haemoglobin-A (Hb-A) solutions; the applied shear rates ranged from 0.624 x 10−3 through 4.59 s−1 . The degree of O2 - saturation (SO2 ) was either above 90% (“oxyhaemoglobin-A” or OxyHb-A) or below 10% (“deoxyhaemoglobin-A” or DeoxyHb-A). Besides O2 ; K+ , Ca2+ and 2,3-bisphosphoglycerate (2,3-BPG) were used as additional effectors of haemoglobin-A Thus, it has been possible to demonstrate: 1) The flow properties of OxyHb-A are strict Newtonian and are independent of any other effector added to the solutions. 2) The…reduction of SO2 does not alter the linear torque - shear rate relationship as known for OxyHb-A. 3) K+ at 0.3 mmol/g DeoxyHb-A does not interfere with the Newtonian behaviour of DeoxyHb-A. 4) Ca2+ at 4 μmol/g DeoxyHb-A has no measurable influence on DeoxyHb-A rheology; at 24 μmol/g DeoxyHb-A, however, a fourfold rise in the viscosity of DeoxyHb-A was observed. 5) The addition of 2,3-BPG at fractions of 20 and 30 μmol/g DeoxyHb-A led to a 1.4 - fold increase in DeoxyHb-A viscosity for solutions with a DeoxyHb-A concentration below 32 g/100 ml; above 33 g/100 ml, however, the increase was 2.3 - fold if 2,3-BPG was present at the high relative concentration. 6) Microscopically, particle formation has been ascertained for the cases of increased viscosity in 4) and 5). This development of heterogeneity proved to be a reversible process on reoxygenation.
Keywords: human haemoglobin-A, polymerization, deoxygenation, viscometry, calcium, 2,3-bisphosphoglycerate, erythrocyte