Clinical Hemorheology and Microcirculation - Volume 12, issue 5
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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: In the absence of species-specific haematological reference data for the vast majority of vertebrate species, a broad comparative approach is of value because it allows general patterns of variation to be identified. This paper presents a broad overview of qualitative and quantitative variation in avian and mammalian haematological characteristics. Morphological differences are most apparent in the erythrocytes and haemostatic cells of vertebrates. Some quantitative parameters, such as red cell number (RBC) and red cell size (MCV) vary widely among species whereas others, such as haemoglobin concentration (Hb), packed cell volume (PCV) and mean cell haemoglobin concentration (MCHC) vary little. These…findings may have implications for understanding variation in haemorheological properties of different species. The results also provide guidelines for clinical interpretation in species for which reference data are not available.
Keywords: Comparative haematology, vertebrate haematology red cells, wildlife health
Abstract: A study has been made of the viscosity characteristics of the blood of a wide variety of mammals, and of related factors, ie haematocrit, plasma viscosity, plasma fibrinogen and MCV. Good correlations have been found between blood viscosity and both haematocrit and plasma viscosity across the various species studied. No such correlations were found with fibrinogen level or MCV.
Abstract: In all vertebrates the delivery of oxygen to the tissues occurs via erythrocytes. Yet among vertebrates significant differences exist in the structure and deformability of these cells. The most significant differences exist between mammalian and non-mammalian cells. Non-mammalian red cells contain nuclei and extensive cytoskeletal structures including intermediate filaments and microtubules. Mammalian red cells are anucleate and contain a simple solution of hemoglobin in their interior. Their deformability and stability are completely determined by the mechanical properties of the membrane. Because of these structural differences, nucleated cells are significantly more rigid than anucleate cells. In particular, the marginal band, a…microtubular structure at the periphery of nucleated red cells, acts to stabilize these cells against indentations at their rim. The most significant limitation on the deformability of mammalian cells is their limited ability to change either surface area or volume. These constraints place strict limits on the sizes of apertures that these cells can negotiate. Within these constraints, the cellular deformability is limited by the shear elasticity of the membrane. Differences in the size, surface to volume ratio, and membrane elasticity of cells from different animals provide clues to the structural basis and physiologic importance of red cell deformability.
Keywords: Red cell deformability, vertebrate animals, cell membrane
Abstract: Seals place extreme demands on circulatory blood flow during dives, yet hemorheological information for these marine mammals is limited. We have thus investigated several hematologic and rheologic parameters in three phocid seals: elephant seals (ES, Mirounga angustirostrisl. ringed seals (RS, Phoca hispida) and Weddell seals (WS, Leptonychotes weddelli). Salient results included: 1) elevated hematocrit (ES = 62, RS = 51, WS = 64%); 2) large MCV (ES = 179, RS = 122, WS = 153 fL); 3) increased MCHC (ES = 41, RS = 39, WS = 41 g/dll. with calculated RBC cytoplasmic viscosities based on MCHC being two- to…four-fold higher than human; 4) species-specific fibrinogen levels (ES = 0.16, RS = 0.17, WS = 0.66 g/dl). RBC aggregation (Myrenne and ZSR, 40% hematocrit in plasma) was also species specific: 1) extent of aggregation [AI] (ES = 24, RS = 0, WS = 32, human ≈ 17); 2) aggregate strength [GTM] (ES = 105, RS = 3, WS = 220, human ≈ 61s−1 ); 3) ZSR (ES = 0.62, RS = 0.41, WS = 0.75, human ≈ 0.52). Blood viscosity data (Contraves LS-30, 40% hematocrit in plasma) again indicated variations among species; WS blood was markedly non-Newtonian with elevated low shear viscosity, whereas RS blood exhibited much lower, nearly Newtonian viscosity — ES blood was intermediate in flow behavior. Viewed collectively, these results indicate marked rheologic “abnormalities” for seal blood which, however, are not associated with pathophysiologic findings; they thus suggest adaptive mechanisms in these animals and the potential value of aquatic mammals as model systems for clinical hemorheology studies.
Abstract: The rheological properties of the blood and its components depend greatly on the flow conditions. Because of the complexity of hemodynamic conditions and the rheological properties of blood, it is almost impossible to obtain information which is directly relevant to in vivo rheological behaviour of blood by ex vivo studies only. The effects of rheological alterations on the overall hemodynamic picture should be tested in the living bodies in order to be able to include all of the above mentioned complexities. Under experimental conditions the easiest way to do this is by using an animal model. The dog as an…experimental animal seems to be the most extensively studied hemodynamic model. There is a large collection of published data on the dynamics of blood flow in general and the specific circulatory systems of the dog including well developed mathematical models. However these models do not include hemorheological parameters and should be extended to cover the role of the rheological behaviour of the blood.
Abstract: Nimodipine is a calcium-antagonist agent capable of acting specifically on brain circulation. The aim of this clinical study was to evaluate possible changes of brain perfusion and blood viscosity in 11 patients with chronic and clinically stable cerebral ischemia after long-term treatment with the oral administration of nimodipine (30 mg 3 times daily for three months). Blood flow in the brain was measured using a Single-Photon-Emission Computed Tomography (SPECT) after the intravenous administration of the tracer 925 Mbq of HM–PAO–Tc99m. Four transaxial slices were chosen: one cerebellar and three supratentorial slices at 4, 5.6 and 7.2 cm above the orbito-meatalline.…The scintigraphic images, obtained before and after the treatment, are compared both qualitatively and quantitatively, using the Index of Cortical Perfusion ( ICP). Blood viscosity was also evaluated (shear rate 90 s−1 and 30 s−1 ) at the same time. After a three month treatment, the scintigraphic images showed an improvement of cerebral blood flow in 9 patients while the mean values of ICP of 11 cases were increased statistically in 13 of the 18 tested regions. A statistically significant reduction of blood viscosity was also observed. This favourable effect of nimodipine in chronic cerebral ischemia can be attribute to its calcium-blocker entry effect, mainly acting on blood, vessels and brain tissue.
Abstract: The H.E.L.P. system (Heparin mediated Extracorporeal LDL <Cholesterol, Triglycerides, Fibrinogen> Precipitation) permits interference into the hemorheologic profile. Using this method, cellular and plasma compartments can be seperated. By lowering the plasma pH to 5.2 it is possible to remove heparinized and precipitated cholesterol, LDL, LP(a), triglycerides and fibrinogen complexes and – after bicarbonate dialysis – to restore the plasma. This procedure was studied in 12 patients with acute thrombembolic stroke and in 14 patients with multi-infarct dementia. Before first H.E.L.P. application no relevant differences in the above-mentioned parameters were found between the two groups. By two H.E.L.P. applications (26 patients)…within 8 days it was possible to repeatably reduce (p<.01) whole blood viscosity (shear rate 11 sec−1 ) from 10.72 to 8.12 and (shear rate 94 sec−1 ) from 5.45 to 4.27, plasma viscosity from 1.50 to 1.23, RCTT from 14.17 to 10.56, fibrinogen from 536.2 to 331.5 mg%, cholesterol from 209.8 to 124.5 mg%, LDL from 122.2 to 60.3 mg%, LP(a) from 20.0 to 10.1 and triglycerides from 186.7 to 70.1 mg%. Further a steady lowering of whole blood viscosity prior to second H.E.L.P. application and after first and second application (p<.01) could be seen. The same phenomenon was observed for RCTT (p<.05).
Abstract: Leukocyte adhesion to endothelium is an important phenomenon in inflammatory conditions and vascular diseases. Monocyte adhesion involved leukocyte adhesion molecules such as the CD11b/CDl8 complex. We have studied the effect of pentoxifylline on the adhesion of monocyte from normal subjects and diabetic patients to human endothelial cells (HEC) in culture and on the expression of CD11b/CDl8 complex on monocytes. Monocyte adhesion was potentiated when HEC were stimulated by interleukin-1β (1L-1β). Pentoxifylline decreased the adhesion of monocytes to unstimulated or 1L-1β stimulated HEC at concentration of 1μM and 5mM respectively. Pentoxifylline has a higher inhibitory effect than hydrocortisone at 0.1mM concentration,…but in association the two drugs had an additive effect. Pentoxifylline at concentrations ranging between 0.1mM and 5mM significantly inhibited CD11b/CD18 expression both in normal subjects and diabetic patients. Pentoxifylline appeared to alter monocyte adhesive properties.
Abstract: Two patients with Waldenström's macroglobulinemia presented with visual impairment in both eyes. The funduscopic examination showed venous engorgement, retinal hemorrhages, microaneurysms, macular and disc edema. Video fluorescein angiography showed marked disturbances of retinal microcirculation. Due to high intravascular concentration of IgM, plasma viscosity was dramatically increased to values higher than 5 mPas. After plasma exchange procedures plasma viscosity dropped to about 2.5 mPas resulting in improvement of retinal microcirculation. Subsequently the funduscopic appearance of the retina improved. When the maculae flattened in the eyes, visual recovery occurred. These cases demonstrate the significance of blood fluidity and especially plasma viscosity on…retinal microcirculation in patients with Waldenström's macroglobulinemia. The improved funduscopic appearance of the retina after the reduction of plasma viscosity proves the pathophysiological correlation between blood fluidity, retinal circulation, and visual function.