Clinical Hemorheology and Microcirculation - Volume 6, issue 2
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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 two expert meetings on standardization of red cell filtrometry have uncovered significant ambiguities in our methodological and conceptional approaches to understand the normal and abnormal rheological characteristics of human blood. Severe methodological artefacts were identified. The present round table addresses these problems showing that presently popular whole blood filtration techniques are not only hampered by artefacts introduced by non-red cells (leukocytes of all subclasses and thrombocytes) but are strongly influenced by the mode of anticoagulation. Furthermore, in tests where these two variables are controlled, there is a very significant influence of small subpopulations of rigidified red cells on the…filtration characteristics on the entire red cell population. Conversely, there is increasing evidence suggesting that a very successful procedure suggested to remove leukocytes also removes the rigid subpopulations. Thence, the suspicion remains that cotton wool filtration introduces a new,albeit subtle artefact.
Abstract: The Imugard IGSOO cotton wool pre-filtration technique, used to remove leucocytes from whole blood prior to study of erythrocyte deformability, has been tested to determine whether it selectively retains less deformable erythrocytes. Leucocyte-free suspensions of erythrocytes prepared in parallel by this technique and by centrifugation in narrow-bore Wintrobe macrohaematocrit tubes gave similar values for filtration through 5 µm pores in the Hemorheometre. Erythrocytes that passed through Imugard IG SOO cotton wool gave similar density profiles to whole blood when fractionated on a Percoll-Stractan continuous density gradient. Erythrocytes retained by, and subsequently eluted from, the cotton wool did not show impaired…deformability as measured by the Hemorheometre or Ektacytometer. We have been unable to demonstrate selective retention of less deformable erythrocytes by Imugard IGSOO cotton wool.
Abstract: Experimental: Two anticoagulants were tested, K2-EDTA and lithium-heparin. Blood was collected in both glass and plastic tubes using EDTA and in glass tubes only when lithium-heparin was used in two forms: dry and in a dilute saline sample. EDTA anticoagulated blood samples collected in plastic tubes were stored at 4°C, room temperature and 37°C. Immediately after the venepuncture and 1, 2, 6 and 24 hours later the following tests were carried out: whole blood filtration (Reid et al., 1976) using Nuclepore Hemafil filters, blood and plasma viscosity at low and high shear rates (Contraves LS 30 and Brookfield LVT viscometers),…blood cell counts, red cell indices (Coulter counter S plus) and hematocrit. The morphology of erythrocytes was studied by means of Scanning Electron Microscopy (SEM) .The specimens of red cells were obtained from the same samples that underwent rheological tests. Results: Using heparin as an anticoagulant, whole blood filtration was severely impaired or blocked and blood viscosity and hematocrit were higher than they were using EDTA. The rheological properties of blood were altered by the storage, even after 1 hour, and the alteration became progressively greater as a function of time. SEM observations contributed to clarifying the effect of anticoagulants and storage conditions on the rheological properties of blood showing several changes of red blood cell morphology.
Keywords: Anticoagulants, Blood storage, Blood filtration test
Abstract: The Single Erythrocyte Rigidometer (SER) has been applied to measure various extrinsic and intrinsic factors involved in red blood cell (RBC) passage time through a single pore membrane. The SER allows to measure the mean passage time (MPT in ms) of 250 single RBC’s each under a relevant and low constant pressure gradient of 70 Pa (τ = 3 Pa) through single pores of defined geometry (SEM measurements). Furthermore a computer program provides us with a list of every single RBC passage time, a flow distribution curve and the MPT of the 10, 5, 2.5, and 1% slowest RBC’s…(“subpopulation”). In the course of the present investigation extrinsic factors like pressure gradient and pore geometry have been examined. MPT correlates directly with pore diameter, RBC shape, and volume. Also the influence of leucocyte removal by cotton wool filtration has been examined. Even the filtration of control RBC increased the MPT by 9% (n = 47). Furthermore we evaluated the influence of different intrinsic factors on RBC deformability. To simulate the imbalanced metabolic situation under pathophysiological conditions we have changed in vitro different parameters. Buffers of different stress degree have been composed and applied to pharmacological characterisation of compounds. Additionally all RBC preparations have been checked for possible subpopulations of rigid cells. The detection of rigid subpopulations was dependent of the pore diameter and they were even detectable in control blood.
Keywords: Single Erythrocyte Rigidometer, red cell deformability, stress factors, rigid subpopulations
Abstract: The influence of different molecular weight dextrans (MW: 6000, 10 000, 40 000, 70 000), hydroxyethyl starch, gelatine and albumin on plasma viscosity, apparent whole blood viscosity and erythrocyte flexibility was studied in vitro. Compared to blood samples two hours incubated with Ringers solution alone, dextrans of 40 000 and 70 000 molecular weight caused the most pronounced increase in plasma viscosity, erythrocyte aggregation and decrease in erythrocyte flexibility. For albumin, hydroxyethyl starch and gelatine these effects were less, but still significant in comparison to the control measurements. The commercially available dextran solutions for clinical use vary widely with…respect to their molecular weight (MW distribution: > 90% of the total amount within the range of 10 000–80 000). It has also been demonstrated, that the high molecular weight components are excreted at a lower rate, which leads to an increase of plasma concentration during repeated infusions (ARTURSON 1954, (1)). The results of our in vitro study support the hypothesis that the increase in apparent whole blood viscosity after repeated infusions, as demonstrated in several clinical experiments is due to an increase of higher molecular weight components, which accumulate in plasma during prolonged infusions with LMWD.
Abstract: We have studied the acute effects of smoking two cigarettes with a high nicotine content in young healthy smokers. The haemorheological profile (blood and plasma viscosity and blood filterability), the peripheral haemodynamics (blood flow in the limbs, at rest and during reactive postischemic hyperemia using a strain gauge plethysmograph) and the metabolic pattern (acid-base balance, oxymetric values and COHb) have been evaluated before and after smoking. Results have shown that cigarette smoking provokes besides an evident increase of COHb, a decrease of blood filterability and an impairment of the last phase of the reactive hyperemia with the lenghtening of the…total time. These data suggest that a possible impairment of the blood flow at microcirculatory level can occur in these subjects after cigarette smoking.
Abstract: The viscoelastic behavior of coagulating plasma and whole blood were examined in a modified thrombelastograph. We found that platelets greatly increased the measured rigidity of coagulating blood and plasma, and this rigidity was augmented by erythrocytes. Red cells also slowed the rate of stiffening, which may be due to the red cell membrane activity. In whole blood, the relaxation of stress at constant strain demonstrated a biphasic pattern: the early rapid phase depended on the primary orientation of fibrin into a network by platelets and red cells. The second slower phase was dependent on Factor XIII activity in secondary rearrangement…of the network. Crosslinking of fibrin by Factor XIII had little effect on rigidity.