Clinical Hemorheology and Microcirculation - Volume 14, issue 4
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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: Two circulations of material in the human body are stated in ancient literature of traditional Chinese medicine (TCM), namely Qi (vital energy) circulation and Xue (blood) circulation. Blood stasis syndrome (BSS) is one of the important syndromes in TCM. BSS is involved in many of the main diseases. The diagnostic criteria for BSS are established, covering traditional and laboratory criteria. Hemorheological abnormalities are one of them. The principle treatment of BSS is activating blood circulation to remove blood stasis (ABCRBS). The progress in the treatment of BSS by ABCRBS reveals promising clinical benefits and encouraging efficacy in hemorheological factors.
Keywords: blood stasis, blood viscosity, coagulation, hemorheology, platelet, traditional medicine
Abstract: The Diabetes Control and Complications Trial (DCCT), an NIH-sponsored study at 29 institutions in the U.S. and Canada, was designed to examine the effects of intensive management in type I diabetes. Between 1983 and 1989, 1441 patients with and without mild retinopathy (primary and secondary) were randomized into two major treatment groups, intensively and conventionally treated patients. Retinopathy, nephropathy, and neuropathy were assessed periodically in each patient. In this study, levels of fibrinogen, haptoglobin, albumin and total protein were measured and viscosity of fresh blood was simultaneously evaluated in 45 local DCCT patients. Viscosity was measured at 17 rotation rates…arranged logarithmically from .03 to 300 inverse seconds shear rate on blood adjusted to 41% hematocrit by the addition or removal of its own plasma. Blood's time-based flow properties — transient resistance and viscoelasticity — were also assessed. Blood viscosity showed the greatest elevation (10 to 19%) in the 0.08–2.0 inverse second shear rate range. Increased low shear rate blood viscosity was found to be linked to fibrinogen and hemoglobin A1c levels. In addition to steady flow blood viscosity measurement, blood's time-based flow properties were also assessed at 15 inverse seconds shear rate. Transient resistance was increased 30% in diabetes; its elevation was found to be linked to both fibrinogen level and low shear blood viscosity. Diabetic blood's viscoelasticity at this high shear rate was much less strikingly increased than its transient resistance. Viscoelastic strain energy was correlated with fibrinogen, low shear viscosity, haptoglobin, and albumin level. Interleukin-6 (IL-6), a potent stimulator of fibrinogen and haptoglobin synthesis in hepatocytes in culture, was found to be elevated in diabetes, indicating that it is the likely mediator of the observed plasma protein changes. The altered blood flow properties observed in this well-characterized group of type 1 diabetes mellitus patients may play a role in development of diabetic complications.
Keywords: diabetes mellitus, type I diabetes, blood viscosity, transient resistance
Abstract: The Diabetes Control and Complications Trial (DCCT), an NIH-sponsored study at 29 institutions in the U.S. and Canada, began in 1983 to examine the effects of intensive blood glucose management on the complications of type I diabetes. About half of the 1441 patients studied were randomized into a conventional treatment group and half into an intensive management group. About half of each treatment group had diabetes of 1–5 years duration and no retinopathy at randomization (primary) and half had diabetes of 1–15 years duration and minimal retinopathy at randomization (secondary). Hemoglobin A1c levels were regularly measured. Information about complications collected…systematically included retinal photographs, nerve conduction velocity assessment and evaluation of albuminuria and renal function. Differences in mean Hemoglobin A1c level between the intensively-treated group and the group continuing their usual treatment were sustained and substantial. Mean hemoglobin A1c levels were 1% compared to 3% above the normal range. We measured fibrinogen, haptoglobin, albumin and total protein levels of 1347 patients from April to August of 1991. Mean fibrinogen (measured both by coagulation quantification and clotting time after dilution) and haptoglobin were elevated and albumin level modestly depressed in the overall DCCT group and gender-based differences were also noted. Despite past reports linking diabetes control to plasma protein levels, no trend to normalization was found in the intensively treated group. In fact, mean haptoglobin level was modestly higher in the intensively treated compared to the conventional group. The primary and secondary prevention components had a well-defined difference in total plasma globulin, linked to marginal differences in albumin and total protein level. The globulin was higher in the secondary prevention group, who by study design manifested more microvascular changes. Intensive management of diabetes has no direct favorable effect on the levels of the major blood proteins that influence blood's flow properties.
Keywords: diabetes mellitus, type I diabetes, fibrinogen, haptoglobin, plasma albumin
Abstract: The deformability of polymorphonuclear leukocytes (PMN) from patients with type II diabetes, from elderly healthy, and from young healthy controls has been investigated by two techniques. Partial micropipette (i.d. 2.7–4.0 μm) aspiration of individual PMNs under constant aspiration pressure of 8 mm H2 0 and measurement of the aspirated length as a function of time (creep experiments) and filtration studies, using the Hemorheometer, of PMN suspensions (2.2·106 cells/ml) through 5 μm Nuclepore filters under 6 cm H2 0 driving pressure have been carried out. The creep curves were similar in all three cases with both the diabetic and…the elderly PMN showing a statistically significant decrease (p<0.001) from the control ones in deformability, while there was no significant difference between them. The initial filtration flow rate experiments (performed only on diabetic and control samples) exhibited a decreased deformability of the diabetics, which was not statistically different, however. The increased rigidity of these leukocytes in diabetes and in ageing may be a contributing factor in the observed microvascular flow disturbances in these situations.
Abstract: A system for direct observation and video recording of red blood cells (RBC) under flow, and computerized analysis of their aggregability was constructed. A narrow-gap flow-chamber was designed, in which a blood sample is subjected to controllable flow. Software was developed to provide the RBC aggregate size distribution at different shear stresses. From the size distribution curves the average or median size (or any other percentile) of the aggregate population as a function of shear stress, as well as the shear stress required for complete disaggregation, can be derived. The kinetics of spontaneous aggregation, in stasis, from singly dispersed cells,…as well as the disaggregation kinetics at varying shear stress, can be derived from temporal monitoring of the cells images. This system provides quantitative measures of RBC aggregability from direct visual monitoring of the aggregation and disaggregation processes.
Abstract: The change of rheological properties of blood during aggregation and subsequent sedimentation of erythrocytes was monitored by a new rheological technique. A damped oscillation type rheometer used can sensitively measure logarithmic damping factor (LDF) which is closely related to fluidity or/and viscosity and viscoelasticity of blood. The LDF value increased and then decreased with the progress of aggregation and sedimentation of erythrocytes. The results were compared with the Westergren method which has been still used as a routine examination of erythrocyte sedimentation (ES) in clinical practice. Good correlations between the LDF curve and the ES curve were observed in blood…of normal subjects and patients with different diseases. It is shown that the present method is capable of estimating the value of erythrocyte sedimentation at one hour within 10 to 20 minutes.
Keywords: erythrocyte sedimentation rate, aggregation of erythrocytes, rheological measurement, damped oscillation rheometer, the Westergren method
Abstract: The flow properties of aggregating red cell suspensions flowing at low rates through horizontal tubes are analyzed using a theoretical model based on microscopic observations. It is assumed that aggregated red cells form a cylindrical core which is eccentrically located in a horizontal tube due to sedimentation in a steady-state. The cylindrical core surrounded by a uniformly dispersed suspension of individual red cells moves with a uniform velocity along the tube axes. The velocity distribution within the tube is calculated on the assumption of unidirectional, incompressible flow. From this result the relative viscosity is obtained as functions of the size,…eccentricity and hematocrit of the core and a discharge hematocrit. It is shown that the relative viscosity increases monotonically with increasing the eccentricity. The simplified model also shows the presence of a certain condition under which the relative viscosity of aggregating red cell suspensions becomes lower than that of non-aggregating suspensions.
Keywords: red cell aggregation, rouleaux, blood viscosity, red cell sedimentation, microcirculation
Abstract: The two major determinants of rouleaux formation in a red cell suspension are the properties of the aggregant (its molecular form, concentration etc) and of the erythrocyte (its deformability, membrane properties, shape etc). While much is now known about the former, relatively little information is available on the latter, and particularly on the membrane factors that are important. One way of obtaining insight into this area is to degrade the membrane with various enzymes and observe their effects on rouleaux formation. This paper is intended as a short review of the field.
Abstract: We have measured deformability of leucocyte subpopulations by a filtration method in long-standing type 1 (insulin-dependent) diabetic patients and in type 2 (non-insulin dependent) diabetic patients compared with control subjects to determine if leucocyte deformability is impaired in diabetes, particularly in association with microvascular complications. Mononuclear leucocytes deformed less readily than polymorphonuclear leucocytes in both diabetic and non-diabetic subjects. There was no significant difference in either mononuclear or polymorphonuclear deformability between either group of diabetic patients and control subjects, but there was a significant association of age with both decreasing mononuclear and polymorphonuclear deformability. Diabetes does not adversely…affect leucocyte deformability and therefore altered leucocyte rheology is unlikely to be causally related to microvascular complications in longstanding diabetes. However increased leucocyte rigidity associated with advancing age could have detrimental effects on microvascular perfusion, which may be a determinant of organ damage in patients with macro and/or microvascular disease.
Abstract: The rheological action in human erythrocytes of oxpentifylline, a synthetic dimethyl xanthine, has been studied using blood from healthy controls and from patients with sickle cell anaemia. Calcium flux measurements using 45 Ca and the dihydropyridine D-600 (methoxyverapamil) were used to define a specific fraction of Ca entry into human erythrocytes. Oxpentifylline was found to inhibit the D-600-sensitive Ca flux (IC50 in the order of 0.5 mM) and may therefore protect sickle cells against Ca-mediated dehydration. Sickle cells were then dehydrated by 15 hours of cyclical oxygenation-deoxygenation in Ca-containing buffer. Oxpentifylline (1 μM–5 mM) failed to prevent Ca-induced loss…of cation via the K efflux (Gardos) channel. Thus the inhibitory effect of oxpentifylline on mediated Ca-entry is insufficient to prevent Ca-dependent dehydration of sickle cells. Inhibition of the Gardos channel in addition would seem to be necessary for a significant anti-sickling effect.