Clinical Hemorheology and Microcirculation - Volume 12, issue 6
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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: Chronic diabetes mellitus is associated with difficulties that have in common a disturbance of the circulation. A clearly defined hemorheologic burden antedates and is cross-sectionally related to the diabetic circulatory complications, suggesting that blood flow plays a role in damaging diabetic blood vessels. This concept has led to the development of hemorheologic models for both micro- and macroangiopathy. Intensive insulin therapy appears to benefit the diabetic hemorheologic burden, but it has limits that make it unable to normalize blood's flow properties. Other interventions can be identified, based both on drugs and on changes in health habits. They have little or…no effect on blood glucose levels but decrease the hemorheologic burden; fourteen means to improve diabetic blood flow are identified and discussed. Four non-drug managements are already often used in treatment. Ten types of pharmacologic agent have clear potential for reducing or preventing diabetic vascular problems. The strength of evidence for their effects and their possible mechanisms of action are discussed. Establishing a more effective role for these agents in diabetes management will require more sophisticated interventional studies that incorporate modern hemorheologic assessment into their design. Such evaluations are important in examlnlng both established and new drugs if we are to further improve the prognosis for individuals with established diabetes.
Abstract: Copley (1) reminds us that the science of haemorheology includes study of the vessel wall as well as the components of the blood. This concept is particularly relevant to rheological studies in patients with sickle cell anaemia who exhibit a complex prothrombotic abnormality affecting vasomotor tone and vascular endothelium as well as the plasma and red cells. Such rheological complexity is further compounded by acute-phase changes secondary to cytokine release from ischaemic tissue. Serial longitudinal study of homozygous patients in the asymptomatic steady state has now suggested a fluctuating balance between accumulation and removal of poorly deformable and dense sickle…cells which is associated with sub-clinical episodes of tissue ischaemia. In the prodromal phase of the painful sickle-cell crisis, there is also an accumulation of rheologically compromised dense cells which may be of aetiological significance in relation to the vaso-occlusion that results in established crisis.
Abstract: Prospective epidemiological trials have identied fibrinogen as a major, primary, cardiovascular risk factor. There are, of course, strong associations between fibrinogen and other risk factors, but the risk factor potential of fibrinogen is independent of these. Fibrinogen might also be a secondary risk factor, i.e. a variable with considerable predictive power after a major cardiovascular event. Our knowledge about the variables determining and regulating the highly variable plasma level of fibrinogen in health and disease is still incomplete. The mechanisms involved in the atherogenic action of fibrinogen are probably diverse. Blood coagulation, blood rheology, platelet aggregation, direct effects of fibrinogen…or its metabolites on the vessel wall and the “Copley endoendothelial fibrin lining” may all represent or provide interacting phenomena of importance. It is concluded that fibrinogen is a major, independent cardiovascular risk factor that should be included in the up-dated risk profil.
Abstract: The blood monocytes adhere to endothelial cells unstimulated and after stimulation by interleukin-1, tumor necrosis factor or other mediators. This process is mediated through specific molecules on both endothelial cells and monocytes. Using specific monoclonal antibodies and molecular cloning several families of molecules involved in leukocyte-endothelial cell interaction have been defined. Leukocyte adhesion molecules include the three β2 integrins (CD11/CD18 molecules), VLA-4 and the L-Selectin. E-Selectin (ELAM-1), P-Selectin (GMP-140) and receptors of the immunoglobulin superfamily (ICAM-1, ICAM-2 and VCAM-1) are expressed on endothelial cells in basal conditions and after activation by cytokines. It has been shown that these adhesive molecules…are involved in blood monocyte adhesion to endothelial cells in vitro. The in vivo expression of these adhesive molecules on the vascular endothelium has been described in acute and chronic inflammatory situations such as Kawasaki syndrome and atherosclerosis.
Abstract: Based on rotational viscometry of clotting, an approach for evaluation of antiplatelet drugs and anticoagulants was explored. Rat platelet rich plasma (PRP) and platelet poor plasma (PPP) were prepared. PRP and PPP were seperately incubated with and without drug (D), namely, PRP, PRP+D, PPP, and PPP+D. Recalcification of the samples were monitored by HAAKE Rotovisco RV20/CV100 at 0.3 s−1 . The inhibition of platelet involvement (IPI) and the inhibition of plasma clotting (IPC) were defined. According to three clotting parameters (tr, dη/dt, τm), six inhibitions (3 IPI, 3 IPC) were obtained for evaluating a drug. The preliminary investigation on heparin,…pentoxifylline, aspirin, notoginseng saponins and alcohol indicated that the approach would be a promising mean for pharmacological and clinical practice.
Abstract: Red blood cell (RBC) deformability remains a central issue in clinical hemorheology and thus we have developed a simple quantitative approach to determine this cellular mechanical property. The method is based upon the analysis of light transmission (LT)-shear rate relations for RBC suspended in various media. LT measurements are performed with a small (0.025 ml) sample of RBC suspension via a computerized Myrenne cone-plate shearing system; LT values are measured at eight shear rates from 5 to 500 s−1 using specially developed software. With appropriate combinations of hematocrit and suspending media viscosity, linear relations (r>0.997) between LT and log…(shear rate) are obtained for cells in non-aggregating media. LT-shear rate relations are markedly affected by cell rigidity, such that LT decreases for less deformable RBC (i.e., dense or heat treated cells). Simplification of the procedure is possible by testing RBC in aggregating media (e.g., plasma) and measuring LT at 500 s−1 (LT500 ) to completely disperse aggregates; LT500 values in both non-aggregating and aggregating media are lower for less deformable cells. The method is sensitive, reproducible (CV < 2%) and can be performed in less than three minutes; LT500 values can be obtained within seconds and for RBC in plasma are available during routine aggregation measurements. The methods thus appears to be relevant to clinical studies of erythrocyte deformability.
Abstract: Interaction between platelets and granulocytes may contribute to ischaemic and inflammatory disorders. We have used a recently developed granulocyte aggregation assay, in which isolated granulocytes and platelet-rich plasma (PRP) are mixed, to test the ability of a range of pharmacological agents to inhibit this interaction. A stable prostacyclin analogue (Iloprost) could completely inhibit platelet-induced granulocyte aggregation if the whole blood was treated immediately following withdrawal, but not if the agent was added to granulocytes or PRP after isolation. A surfactant (Poloxamer 188) added to the whole blood, either increased aggregation or had no effect, depending on the source of the…compound under test. Naftidrofuryl oxalate and pentoxifylline tended to reduce aggregation, but these effects were not statistically significant. It appears that agents which can inhibit platelet activation may reduce adhesion to granulocytes, but are unable to reverse the interaction after the platelets have been stimulated.
Abstract: Copley hypothesised the existence of an endoendotnelial fibrin lining of blood vessels; while the Rokitansky-Duguid hypothesis suggests that ongoing fibrin formation on the arterial wall contributes to atherosclerosis. We assessed in vivo fibrin turnover by measurement of plasma levels of cross-linked fibrin degradation products (D-dimer antigen) using a sensitiveimmunoassay, in 68 patients with extensive atherosclerosis (chronic peripheral arterial disease) compared to 239 controls (a random population sample in the same area). Plasma D-dimer levels were significantly higher in patients than controls (p<0.01) and correlated with clinical severity. We suggest that the plasma D-dimer level may be a useful index of…intravascular fibrin turnover and of the ongoing contribution of thrombosis to arterial disease.
Abstract: The role of either plasmatic or cellular factors in the erythrocyte aggregation has been quantitatively examined in type I diabetes mellitus by studying the variations in the light backscattered by an aggregating blood suspension. The erythrocyte aggregation parameters measured on cells from diabetic patients resuspended in autologous plasma were significantly impaired when compared to the values observed on erythrocytes from healthy controls resuspended in their own plasma. Aggregation was significantly lower when erythrocytes from diabetic patients were resuspended in normal plasma Conversely, it was noted a significantly higher aggregation when normal erythrocytes were resuspended in plasma from diabetic patients as…compared to normal plasma. Similar cross-match experiments showed that erythrocyte membrane lipid fluidity is not affected by resuspension of red cells in different plasmas. These results underly the major role of plasmatic factors in erythrocyte hyperaggregation in type I diabetes mellitus.
Keywords: Type I diabetes mellitus, Erythrocyte aggregation, Plasma proteins, Membrane
Abstract: Strictly normovolemic. individualized exchange hemodilution is rapidly developing into the most potent therapeutic remedy of clinical hemorheology. Firm evidence from critically ill patients show that resolute reduction of the hematocrit level down to around 0.33 l/l is both safe and efficient in the treatment of various localized and global low flow states (or “hypokinetic” circulatory situations), provided that anaemia is accompanied by careful (and if possible monitored) maintenance of the cardiovascular filling pressure. Under these conditions the oxygenation and the performance of the myocardium (14) is maintained, as is the peripheral vascular bed in patients with decompensated POAD (30). The…significance of the latency between critical vascular incidents (shown in central retinal artery occlusion (27)) has come to the forefront. Urgency of treatment and the recruitment of expert intensive care competence has now led to the administration of “custom taylored hemodilution” in the treatment of cerebrovascular stroke. As shown by the success of the AMSTERDAM STROKE STUDY (Goslinga et al. 1992), when carefully separating exsiccated from non-exsiccated patients, mortality in both groups can be dramatically reduced by either aggressive rehydration or custom-taylored exchange hemodilution (Hct 0.32 l/l, pulmonary capillary wedge pressure 12 mmHg). Reduction of mortality from the conventional value of 30% down to 16 or 9%, accompanied by an elevation of full rehabilitation from 34 to 59 (and 48%) by far exceeds the success of any competing form of therapy. As an explanation for the obvious success of induced anaemia, the new paradigm of “optimum circulatory stability” for hypokinetic states by means of normovolaemic dilution has been formulated from theoretical, experimental and clinical studies. It focusses on the preponderance of benefits from iatrogenic dilution over normal hematocrit in bed ridden patients, and is set in opposition to the paradigm of “maximum oxygen transport efficacy”, which is largely irrelevant in low flow states.
Abstract: A survey is given which describes the actual situation of the rather new science of Perihemorheology, a term introduced by ALFRED L. COPLEY. Perihemorheology includes the exchange of rheological processes between the vessel - blood organ and its surrounding tissues as well as in reverse. The article summarizes the anatomical and physiological basis and includes own methodical approaches to the experimental and clinical pathophysiology of the Perihemorheology: the permeation through the blood vessel wall, the transport in the interstitium, the lymph production.
Abstract: In this study we attempt to clarify the pathophysiological significance of PFL determined by means of negative pressure filtration system using Nuclepore membrane. The platelet suspension was filtered through the Nuclepore membrane. In the course of filtration pressure difference was generated between the upper and lower sides of membrane due to the PFL. The difference pressure thus generated was detected by a sensitive transducer, variable inductive type, amplified and recorded as a differential pressure curve. The experiment was carried at 37°C in the constant temperature bath. PFL was found to be affected by some factors: 1) A decrease in PFL…was observed more significant in suspension of EDTA-platelet compared to that of citrate-platelet. 2) EtTect of ADP on PFL showed to decrease in both suspensions of EDTA and citrate-platelet after addition of ADP in final concentration of 7.5 μmol. However, in the case of citrate-platelet a more significant decrease than that of EDTA-platelet was observed after addition of ADP. 3) Mean platelet volume (MPV). Volume of platelet changed to increase approximately 10% was observed after addition of stimulants such as ADP. 4) PFL in diabetes showed decreasing along with HbA1 concentration. These changes of PFL caused by various factors would contribute to disturbances of microcirculation following microangiopathy.
Abstract: Physicochemical and hematological studies were performed on the blood and blood components from 227 clinically definite multiple sclerosis patients and 64 matched control subjects. Measurements included plasma and serum viscosity, screen filtration pressure, red blood cell osmotic and mechanical fragilities, erythrocyte sedimentation rate, hematocrit, total serum protein, platelet count, thrombo-Φ-time, platelet retention, platelet aggregation induced by ADP, collagen or ristocetin; plasma protein levels of fibrinogen, albumin, α-1, α-2, β- and γ-globulins, albumin/globulin ratio and standard chemistry screens for levels of sodium, potassium, calcium, glucose, cholesterol, triglycerides, LDH, SGOT, total bilirubin and uric acid. Highly significant differences were found between normal…and MS patients: red blood cell osmotic and mechanical fragilities were greatly elevated for MS patients; platelet aggregation induced by ADP, collagen or ristocetin, decreased for MS patients; platelet retention markedly increased in MS patients; and the level of β-globulin decreased while the level of γ-globulins increased in MS.