Clinical Hemorheology and Microcirculation - Volume 9, 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: RBC aggregation is studied on 60 insulin dependent diabetic patients and 61 controls by laser light reflectometry technique. This study indicated a complete REC disaggregation shear stress higher in diabetics than in controls and increasing with retinopathy intensity. Otherwise, we have shown a positive correlation between the disaggregation shear stress and fibrinogen, glycosilated haemoglobin (HbA1C ) or alpha-2 globulins levels. Aggregation was higher when diabetic erythrocytes are suspended in their own plasma than in normal plasma. On the other hand, for cells in the same suspending medium (normal or diabetic plasma, dextran solution), cross-over experiments showed that diabetic erythrocytes aggregates…more than normal erythrocytes. These results suggest that hyperaggregation in diabetics is both related to an increased protein level (fibrinogen) and to an intrinsic membrane erythrocyte abnormality. The relationship between the alteration in erythrocyte adhesiveness and retinopathy was discussed.
Abstract: A nuclepore filtration technique was developed for a clinical evaluation of the deformability of blood cells (red and white) at low shear rates. The filtration process of blood suspensions at low pressure differences was recorded continuously with a microscope-TV-video system. The time course of decreasing filtration pressure was analyzed from the video-monitor. The obtained results are as follows: 1) The relative resistance (Rr ) of the blood suspension increased in the time course of filtration. 2) When negative pressure was added, the Rr remained almost constant and its increasing rate was very slight. 3) A great difference appeared in…the Rr between normal subjects and patients a low pressure difference below around 10 mmH2 O. The Rr showed a difference before and after treating patients. 4) More than 10% WBCs could pass through the nuclepore (5µm diameter). The present nuclepore filtration method showed that the differentiation of RBC deformability at low flow rates was more obvious and sensitive, suggesting it would be useful for clinical applications.
Keywords: filtration test, relative resistance, red cell deformability, white cell plugging, low flow rate
Abstract: With the aid of multiple linear regression analysis, the depedence of whole blood viscoelasticity on different laboratory parameters was investigated. Viscoelasticity was determined by means of an oscillating capillary rheometer at a frequency of 2 Hz and an amplitude of wall shear rate of 10 l/s. The results showed, that the viscous component of viscoelasticity depends mainly on hematocrit and to a small degree on plasma viscosity. The elastic component of viscoelasticity on the other hand is influenced to a greater extent by plasma viscosity and is additionally influenced by the plasma proteins (fibrinogen, albumin, and cholesterol) and platelets. Thus,…81% of the variation found for the viscous and 75% for the elastic component of a reference population of normal donors could be explained.
Keywords: Blood viscoelasticity, oscillatory capillary rheometry, normal values, laboratory parameters, multiple linear regression
Abstract: The influence of RBC mechanical properties and aggregation on the viscoelasticity of whole blood was studied in an oscillating capillary flow. Cell membrane mechanical properties were altered by age separation into old and young RBC, by heat treatment and glutardialdehyd fixation of RBC. The altered RBC were resuspended in autologous plasma. Aggregation was increased adding different amounts of Dextran 110. The results indicate, that changes of RBC membrane elasticity mainly influence the elastic component while changes of membrane viscosity influence the viscous component of complex viscosity. Membrane mechanical effects can be discriminated from enhanced aggregation.
Abstract: Complex viscosity of whole blood in patients with arterial circulatory disorders have been determined under treatment with a Ginkgo biloba extract. The Ginkgo preparation influences the pathologically increased blood viscoelasticity, especially the elastic component. By parenteral daily infusions the viscoelasticity is decreased significantly after 5 to 10 days of treatment. By prolonged oral administration up to 3 months a marked continuous improvement of viscoelastic parameters could be observed. The latter type of response suggests the preparation’s ability to influence the erythropoietic cells and thus forming a new population with normalized hemorheological properties.
Abstract: When normal native or heparinised blood is forced under pressure through a filter with capillary sized holes, platelets aggregate during their passage through the filter which takes 8 ms. When sufficient aggregates are retained the filter blocks. The effluent blood is collected from 0–3s (first phase) and between 10–20s (second phase); the platelets are counted, and the percentage retained is calculated. Normally this is 50±12% and 66±15% respectively. With von Willebrand’s (vW) blood no blocking occurs and platelet retention in both phases is low. With EDTA blood and in the presence of some “membrane active” drugs, the first phase is…normal; retention during the second phase is, however, decreased with no blocking. The use of monoclonal antibodies shows that glycoproteins (GP) IIb/IIIa and vWf are essential for blocking, but GP Ib is not. Thus, aggregation in the first phase requires high shear, vWf and GP IIb/IIIa only, while divalent cations are essential for the second. It is proposed that high shear alone will expose and activate GPr IIb/IIIa; vWf is then essential for platelet aggregation in the filter and fibrinogen is largely irrelevant.
Abstract: Experiments were realized on conscious Wistar rats with preoccluded both vertebral and right carotid arteries. Thrombus formation was induced in the left carotid artery by applying an anodal current of 1 mA during 12 minutes. Following the left carotid obstruction by the thrombus, rats became unresponsive and lost their righting reflex. The ability of various compounds to delay the loss of the righting reflex was investigated. Heparin, prostacyclin, iloprost, the thromboxane receptor antagonist BM 13177 and naftidrofuryl exerted a significant activity, whereas acetylsalicylic acid, dipyridamole, sulfinpyrazone, and the thromboxane synthetase inhibitor, dazmegrel, were inefficient
Abstract: In diabetics, microalbuminuria reflects a multifactorial reversible glomerular dysfunction, announcing further development of overt nephropathy. This study aimes to determine whether microalbuminuria and its rise during a standardized exercise test are related to blood rheology. A cross-sectional study of 47 insulin dependent diabetics showed that impaired values of whole blood filterability (as found in 26 subjects) were associated with an increased resting microalbuminuria (21.755 ± 3.91 µg/min vs 8.125 ± 1.226, p < 0.03) whereas exercise induced rise in microalbuminuria did not differ between the two subgroups and showed no relationship with exercise-induced changes in filterability. Resting microalbuminuria correlated with…blood pressure only in the subgroup exhibiting reduced blood filterability (r = 0.549 ; p < 0.01). Preliminary results of an open study with pentoxifylline (800 mg/day during 3 months) suggest that this drug reduces resting microalbuminuria but not its exercise-induced increase. Those data might be consistent with the following working hypotheses: (a) hemorheologic disorders detectable with blood filterability measurement could impair glomerular microcirculation, increasing its sensitivity to blood pressure. Therefore, they could be an additional risk factor, as previously stated by Solerte. (b) microalbuminuria rise during exercise is not likely to be an artifact resulting from exercise-induced hemorheologic changes, but might be an improved index of abnormalities already existing at rest. (c) our findings seem to be consistent with previous reports suggesting a beneficial effect of pentoxifylline in this process. However, this latter concept requires further investigations.