Clinical Hemorheology and Microcirculation - Volume 7, 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: The red blood cell membrane is a complex medium with rheological characteristics which may be understood in terms of macroscopic, microscopic and molecular properties. Rheological parameters at the molecular level are electrical surface charge and lipid fluidity. Surface charge results from the presence of ionized chemical groups at the cell surface and may be approached with cell electrophoresis methods. Among the most widely applied methods for studying membrane fluidity, electron spin resonance (ESR) and fluorescence polarization have been the subject of a large number of studies. This paper briefly describe the principles of these methods used to account for molecular…rheology. As membranes alterations are associated with pathological processes of red cells, the methods may also be useful in the field of clinical research and the authors consider the clinical applications of these methods to the red blood cells.
Keywords: Molecular rheology, surface charge, cell electrophoresis, lipid fluidity, electron spin resonance, fluorescence polarization, red cell membrane
Abstract: Some results on the use of viscometry in clinical hemorheology investigation are presented. First, viscometric quantities used in Couette viscometry such as shear rate, shear stress and apparent viscosity are defined. Then, are given details on the two modes of measurement: steady state and unsteady state flow modes. In the former, shear-thinning rheograms are presented and related data processing is indicated. In the latter, transient rheograms and hysteresis loops are shown and indices of viscoelasticity and thixotropy are defined. Corresponding rheological behaviors are linked to blood structure which is modified by shear stresses. Examples of viscometric data are given for…suspensions of artificially modified RBC in the cases of: (i) modifications of RBC aggregation, (ii) modifications of RBC shape and RBC deformability. Finally, clinical applications of viscometry on pathological bloods are given in the cases of insulino-dependent diabetes, Raynaud phenomenon and ischemic cardiopathy with normal coronarography.
Abstract: In aggregation of red blood cells (RBCs) induced by macromolecules, the aggregating energy provided by macromolecular binding to RBC membrane must overcome the disaggregation energy of electrostatic repulsion between RBC surfaces and the effects of mechanical shear stress. Computation of net aggregation energy per unit area (γ a ) from changes in membrane strain energy in stationary RBC aggregates in dextrans and lectins yielded values of 10−2 to 10−3 ergs/cm2 . The difference in γ a between normal and neuraminidase-treated RBCs represents the electrostatic repulsive energy. Moderate shearing enhances RBC aggregation by promoting cell-cell encounter, but high…shear stresses cause RBC disaggregation. The energy required to disaggregate a unit interacting area of RBCs in a flow channel (γ d ) is on the order of 10−4 ergs/cm2. The difference between γ d and γ a suggests that the macromolecular bonds may not have to be broken during shear disaggregation. RBC aggregation can cause an elevation of bulk viscosity of the blood (η B ), but the phase separation due to strong RBC aggregation may have an opposite effect on TlB. The rheological effect of RBC aggregation can also be affected by the geometry of the vessels through which blood flows. Therefore, RBC aggregation exerts complex effects on blood flow resistance and hemodynamics in vivo. RBC aggregation is more prone to occur in the low shear regions of postcapillary venules; the resulting preferential increase of post capillary resistance over precapillary resistance may lead to an elevation of capillary pressure and transcapillary fluid loss. When blood viscosity is elevated by enhanced RBC aggregation, the optimum hematocrit for oxygen transport is shifted to lower levels; hence the low hematocrit values found in paraproteinemias and hemorrhage serve to maintain oxygen transport to tissues.