Clinical Hemorheology and Microcirculation - Volume 15, 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: Taking into account the insufficient analysis of blood rheological disol-ders in the development of arterial hypertension, the most essential factor deranging the normal blood flow in microvessels, the erythrocyte aggregation, was examined using an improved, ‘Georgian’, technique. The red cell aggregability was assessed both in healthy controls and two groups of patients with mild and severe forms of essential hypertension. Even in the mild form of hypertension the erythrocyte aggregability index was found to be almost twice as high as in the healthy control group. In the severe form it was 18% higher than in the mild form of hypertension.…Blood plasma fibrinogen, contributing to the enhanced erythrocyte aggregation, was found significantly increased in the patients. Following therapeutic treatment, both the systolic and diastolic arterial pressures, and the total peripheral resistance decreased. in both groups of patients. The aggregability index and the plasma fibrinogen contents declined simultaneously. It was concluded that the blood rheological disorders, manifested in an enhanced erythrocyteaggregability and blood plasma fibrinogen contents, resulted in the increase of total peripheral resistance and might be reversed in hypertensive patients.
Abstract: The aim of this double blind placebo controlled crossover study is to show that apart from decreasing blood pressure felodipine improves microcirculation. 30 patients with essential hypertension and manifest microangiopathy were included. No patients dropped out on account of side effects although these occunocd in the expected frequencies. The study phases each extended for a week (10 mg/d felodipine or locspectively a placebo). Blood pressure, blood and serum values, nail fold capillary circulation and oxygen partial pressure in muscle were measured. The blood pressure in the placebo phase remained constant. The increase of erythrocyte velocity in cutaneous capillaries and…oxygen partial pressure in muscle and the decrease of poorly supplied muscle areas caused by felodipine relevantly improved the microcirculation of skin and muscle by 50% and 30%. The vasomotor reserve increased by 50% owing to an antispastic effect of the substance. A rheological effect was observed in the form of a decrease in plasma viscosity. Felodipine significantly and loclevantly decreased by 10% the systolic and diastolic blood pressures. Apart from decreasing blood pressure Felodipine causes a relevant and significant global improvement of microcirculation in skin and skeletal muscle tissue.
Abstract: Blood viscosity and yield stress of patients with myocardial infraction and stroke were studied and the observations were cotnpared with those of people who served as control. Viscosity at various shear rates was measured using Weissenberg rheogoniometer equipped with simple cone and plate type of platens. Blood, being a Non-Newtonian fluid, Casson model was used to describe its behaviour adequately. The changes in the independent rheological properties (viscosity and yield stress) of whole blood, packed RBC and plasma were studied. Viscosities of whole blood as well as packed RBC were observed to increase significantly in patients with myocardial infarction, and…stroke. Plasma viscosity also registered increase in myocardial infarction patients, while increase in stroke patients was insignificant. Significant increase iit the yield stress of whole blood in patients with myocardial infarction was observed, but there was no significant change in the yield stress of packed RBC in either category of patients
Abstract: The rheological parameters which indicated the rigidity of red cells, ie., Red cell internal viscosity (ηi ) and plasma trapping were determined in patients infected with Plasmodium falciparum and were compared to that of normal subjects. Plasma trapping was determined and this value is used for packing coefficient (k). There was an increase in plasma trapping in patients which indicated an increase in rigidity of their red cells. The internal viscosity of red cells (ηi ) were determined by the blood viscosity equation: ηr = (1- kCT)−2.5 which was proposed by Dintenfass in 1968. Although blood viscosity (ηb…), plasma viscosity (ηp ) and relative viscosity (ηr ) of the malarial patients were significantly less fuan that of nonnal subjects, the actual volume concentration of red cells (C = Hct/k) of these patients were also significantly less than that of normal subjects. And it was found that the mean Tk value of the patients was significantly higher than that of normal subjects. Since T is equal to (P + 0.4)/(p + 1), where p is ηi /ηp , then the ηi of the patients were significantly higher than that of the nolmal subjects. These findings lead us to postulate that increased rigidity of the red cells is behind the mechanism of vascular obstruction in patients with cerebral malaria.
Abstract: Restenosis after primarily successful percutaneous transluminal coronary angioplasty (PTCA), which occurs in about 30–40 % of the cases remains a major limiting factor of this procedure. In order to study the possible association of the incidence of restenosis and established risk factors of coronary artery disease levels of lipoprotein(a) (Lp(a)), fibrinogen, total cholesterol, HDL-cholesterol, LDL-cholesterol as well as the plasma viscosity were determined in 98 patients who all had undergone follow-up coronary angiography within 6 ± 2 months after PTCA. Clinical parameters, baseline coronary angiography findings as well as the lipid-lowering medication (administered to 45 % of the patients) were…not significantly different between the group of patients with restenosis (n=45) and without restenosis (n=53). A significantly higher risk of restenosis after PTCA was found in patients with Lp(a) levels exceeding 3mg/dl as well as in patients with extensively elevated fibrinogen concentrations (> 400 mg/dl) whereas plasma viscosity showed no differences between patients with and without restenosis after PTCA. While there was no association between the frequency of restenosis and conventional lipid parameters low levels of Lp(a) and very elevated levels of fibrinogen seem to be predictors for an increased risk of restenosis after primarily successful PTCA.
Abstract: Lipopolysaccharide (LPS) of grant-negative bacteria consists of O-specific polysaccharide chain, core oligosaccharide chain and lipid A. Studies on the effect of various endotoxins on red blood cell (RBC) deformability gave conflicting results. To evaluate whether the effect of endotoxin on RBC deformability depends on the presence and exposure of lipid A, we studied the effect of five E.coli LPS components on RBC deformation by means of a shear stress diffractometer: 1) complete E.coli 0111:B4 LPS; 2) delipidated E.coli 0111 B4 LPS; 3) R-mutant E.coli F-583 LPS lacking the O-specific polysaccharide chain; 4) E.coli F-583 lipid A, and 5) electrodialysed E.coli…F-515 lipid A. Electrodialysis results in highly dispersed molecules whereas unelectrodialysed LPS tends to form aggregates. At a shear stress of 6 Pa RBC deformation was not changed by complete and delipidated LPS, but RBC deformation was impaired by Rd-mutant LPS (−12 %) and lipid A F-583 (−10 %) after 30 min incubation. Electrodialysed lipid A F-515 showed the strongest effect and decreased RBC deformation (−24 %) after 30 min incubation. These results indicate that the effect of LPS on RBC deformation depends on the exposure of lipid A for binding to RBC membranes. The polysaccharide chain of LPS weakens the interaction of lipid A and RBC membranes. Furthermore, aggregates of lipid A impair RBC deformation less than highly dispersed lipid A.
Abstract: Cancer is a disease which leads to different systemic changes particularly observed in blood. Plasma viscosity is one of the ways of evaluating such changes. A study of plasma viscosity in oral cancers indicated the status of the disease. In cancer at advanced stage (stage IV), it showed non-Newtonian behaviour. Very high viscosity of plasma at low shear was seen in the patients having poor prognosis.
Abstract: Alterations in the release of acute phase proteins as one of the phenomena of an acute phase response are reportedly initiated by cytokines and glucocorticoids. To determine, whether apolipoproteins are similarly affected, human hepatoma HepG2 cells were exposed for up to 12 days to recombinant interleukin-6 (rhIL-6) either on its own or in combination with dexamethasone. The quantities of the apolipoproteins A-I and B secreted daily were determined, and were compared with those of the known acute phase plasma proteins albumin, fibrinogen, haptoglobin and α2 -macroglobulin. The apolipoproteins responded differently to the mediators: while apo B was down-regulated by both…mediators, apo A-I was not affected by the cytokine but stimulated by the glucocorticoid. A divergent effect of IL-6 and dexamethasone was also observed for α2 -macroglobulin, whereas they interacted synergistically in respect to fibrinogen, haptoglobin and albumin. Apparently, IL-6 and dexamethasone not only operate separately in the regulation of apolipoproteins but also of known acute phase proteins.
Keywords: Apolipoprotein A-I and B, acute phase proteins, interleukin-6, dexamethasone, human hepatoma cells
Abstract: The effects of α - tocopherol nicotinate on hemorheological properties and retinal microcirculation in non-insulin dependent diabetes mellitus (NIDDM) were investigated. Seven female NIDDM with retinopathy orally administered α - tocopherol nicotinate at 300 mg after each meal (i.e., 900 mg/day) for a 3 month period. The treatment with the medicine resulted in a significant improvement in blood viscosity at different tested shear rates (P<0.05 or better), red cell deformability (P<0.01) and retinal capillary blood flow velocity (P<0.05), but not in plastna viscosity and red cell rigidity. This study suggests that treatment female NIDDM with α - tocopherol nicotinate can…improve red cell membrane rheological properties and, consequently, improve retinal capillary blood flow. Therefore, the treatment may be useful in decelerating the deterioration of retinopathy in NIDDM patients.
Abstract: Since the role of microvascular rheological disorders has been so far insufficiently analysed in development of stroke, we examined in course of acute stage of ischemic brain infarcts the most essential feature of disorders - erythrocyte aggregability with ‘Georgian technique’ assuring direct and quantitative data. In addition, ultrasonic Doppler scanning of cerebral arteries, computerized tomography, magnetic resonance imaging, and serial cerebral angiography were repeatedly applied. Index of erythrocyte aggregability was found more than twice higher in acute stage of ischemic brain infarcts than in healthy control group. In a significant number of cases infarcts were produced by microcirculatory stases, related…to enhanced erythrocyte aggregation. Aggregability index was found to be more sensitive as compared to blood plasma fibrinogen content and blood hematocrit for prediction of dynamics and outcome of acute phase of disease. In addition, aggregability designated extent of the accompanied brain edema. We arrived at conclusion that erythrocyte aggregability is a notable feature characterizing the microvascular hemorheological disorders. It represents an essential risk-factor furthering both development of microcirculatory stases and ischemic brain infarcts. Necessarily, it is to be tested with most perfect techniques providing reliable diagnosis and prognosis of the disease.
Keywords: Cerebral infarct, Microcirculatory stases in the brain, Erythrocyte aggregability, Blood flow structuring in microvessels