Clinical Hemorheology and Microcirculation - Volume 13, 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.
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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: The Diabetes Control and Complications Trial (DCCT), an NIH-sponsored study being conducted at 29 institutions in the US and Canada, was designed to examine the effects of close control of type I diabetes. It was started in 1979 and randomized its 1441st (last) patient in July, 1989. Half had diabetes of 1–5 years duration and no microvascular complications and half had diabetes for 5 or more years and background retinopathy. The study will be completed by June, 1994. HbA1c levels and complications information have been recorded, including hypoglycemic events, neurobehavioral changes, retinopathy evaluated both ophthalmologically and using retinal photographs, and…kidney function impairment measured as proteinuria and glomerular filtration rate. I measured plasma levels of fibrinogen, haptoglobin, albumin and total protein from 1347 DCCT patients from April to August of 1991. Treatment classification and HbAlc levels will not be available until the study is completed, but other information was made available for analysis. Fibrinogen (quantitized both by coagulation amount and by clotting time after dilution) and haptoglobin were elevated in diabetes, both being higher in females than males (fibrinogen 9% and haptoglobin 16%). Albumin was more depressed and globulin more elevated in females. Correlations between the four measured parameters were significant but low enough to conclude that they were independently affected. Smoking (n=211) raised fibrinogen 6% and haptoglobin 18% in diabetes. Pregnancy (n=24) raised fibrinogen level 18% while lowering haptoglobin 40% and albumin 16%. The lowering of haptoglobin was unexplained but similar to that described in nondiabetic pregnancy. The increase in acute phase protein level found in type I diabetes was similar to that seen in trauma, inflammation, or neoplasm in nondiabetics; the effect of smoking to further raise protein levels was small, suggesting that the stimulation of acute phase protein changes by smoking and diabetes may operate through a common mechanism.
Abstract: Recently, the deleterious influence of leucocytes in hemorheological disturbances and thrombotic processes has been described. The Platelet-activating factor (PAF) is produced by leucocytes and is also a potent stimulating factor of these cells. It can also activate the endothelial cells and the platelets but in the limited area of its production. A better understanding of its mechanism of action (cell receptors, regulating systems) is necessary to conceive new pharmacological approaches in vascular diseases. PAF antagonists are numerous: some molecules, synthetic or derived from plants extracts, are structural analogues. Other molecules compete with PAF receptors on cells. We review the main…mechanisms of actions of PAF and their consequences in vascular disorders. Pharmacological modulations are also described. Clinical trials could be set up on this basis.
Abstract: Many vascular pathologies have been reported to follow a diurnal rhythm (AMI, angina, stroke, sudden cardiac death, pulmonary thromboembolism) with a peak in the early morning. Aim of the study was to evaluate the existence of a diurnal rhythm of platelet aggregability and blood rheology. The study was carried out in 12 subjects; blood withdrawings were performed every 3 hour for 24 hours and in each blood sample platelet aggregation (on PRP and on washed platelets) and haemorheological parameters (blood viscosity, blood filterability, haematocrit and fibrinogen) were measured. Moreover systolic and diastolic blood pressure was recorded by dynamic monitoring. The…results show that a circadian rhythm of the above mentioned parameters does exists. Even if our data do not prove a strict correlation between these parameters and the incidence of the vascular pathology, it could be interesting to keep in mind the existence of a temporal parallelism when starting preventive therapy.
Abstract: Exercise-induced increase in blood viscosity is supposed to result from modifications in plasma viscosity and hematocrit, while erythrocyte rigidity remains constant. If this assumption is valid, the equations of Quemada and Dintenfass can be used to predict postexercise blood viscosity (μb) at high shear rate from h (hematocrit) and μpl (plasma viscosity), assuming that erythrocyte rigidity (k or Tk) remains constant. We first investigated this hypothesis in 21 children (5 girls, 16 boys, age: 9–15 yr) during a 15 min submaximal exercise (final step: 90% of maximal power output). Values calculated with both equations were highly correlated with measured postexercise…μb: (respectively r=0.932 and r=0.936; p<0.001 for both) i.e. increases in h and μpl statistically “explain” 87% of the variance of μb increase. In a second study the same procedure was applied to 8 highly trained professional football players during a longer exercise-test (ten minutes of increasing workload followed by a 15 min plateau at 85% of the maximal power output). In this case prediction of μb from h and μpl alone gave very poor results, due to an increase in ‘Tk’ and ‘k’ which was observed (p<0.01) when lactatemia exceeded 4 mmol/l. This increase (deltaTk) is correlated with the increase in blood lactate (r=0.562 p<0.01). Thus, our data suggest that (a) as previously described, μpl and h appear to be the main predictors of postexercise μb in most exercise protocols; (b) however, in some cases, e.g. when blood lactate increases above 4 mmol/l, RBC rigidity can be also increased, and changes in μpl and h are no longer the only determinants of postexercise μb.
Abstract: Metabolic modifications associated with the syndrome ‘X’ of Reaven (insulin resistance-hyperinsulinemia syndrome) might explain at least in part the rheologic changes of obesity. This hypothesis was investigated in 101 subjects (38 overweight (Ob+), 22 obese (Ob++) and 41 controls) during a standardized breakfast test. Baseline values of plasma viscosity (μpl), blood viscosity at high shear rate, RBC filterability (Hanss' hemorheometre), hematocrit, RBC aggregation (Myrenne aggregometer) serum cholesterol and triglycerides were measured. When compared to controls, obese patients Ob+ and Ob++ had a higher hematocrit (+2.5 % p<0.02). Plasma viscosity was similar in the three groups. Blood viscosity (at both native…and corrected (45%) hematocrit) is higher in Ob++ (repectively p<0.01 and p<0.04) while Ob+ have values similar to controls. The ratio of blood viscosity (at corrected hematocrit 45%) on plasma viscosity which is related to RBC deformability is higher in Ob++ (p<0.02). On the whole group of subjects (n=101) blood viscosity (at corrected hematocrit 45%) was correlated to baseline insulinemia (r=0.225 p<0.03) and triglyceridemia (r=0.228 p<0.02), but it failed to be correlated to blood pressure in obese subjects. Serum cholesterol was correlated to RBC rigidity in controls. RBC aggregation ‘M’ index was correlated with body mass index (r=0.265 n=88 p=0.0124), cholesterol (r=0.21 n=88 p=0.0462), baseline insulinemia (r=0.37 n=83 p=0.0007) and fibrinogen (r=0.35 n=40 p=0.028). ‘M1’ index was correlated to triglycerides (r=0.21 n=88 p=0.045) and baseline insulinemia (r=0.24 n=83 p=0.0322). These findings suggest that (a) the main hemorheologic disorders in obese are a higher hematocrit and RBC rigidity; (b) metabolic disorders (hyperinsulinemia, hypertriglyceridemia, i.e. signs of the ‘X’ syndrome of Reaven) are associated with hyperviscosity; (c) thus, we hypothesize that hyperviscosity may be a mechanism involved in the vascular risk of hyperinsulinemia (or a marker of such a risk).
Abstract: This study was carried on in order to describe intrauterine fetal blood rheology, and to try to correlate these measurements with hemodynamic data obtained by doppler. Fetuses underwent cordocentesis in utero during pregnancy with a method allowing an ambulatory sampling with no premedication. Pathologic cases (malformations, fetal distress) were excluded from the study. Finally, a group of 80 ‘normal’ fetuses was constituted, covering the period between 25 and 30 week's gestation. When compared to mothers studied at the same time, have significantly lower blood viscosity, lower plasma viscosity, lower RBC flexibility (measured by filterability) and higher hematocrit/viscosity ratio. Measurement of…RBC rigidity by viscometry gave no significant differences. Fetal RBC aggregation was studied in 52 samples and was very low when compared to mothers with ‘M’ values equal to zero before 30 wks. The following parameters are linearly related to time: blood viscosity, hematocrit, hemoglobin count, RBC count, WBC count, eosinophil count, RBC aggregation index ‘M’. A correlation between umbilical artery resistance index and both whole blood viscosity and hematocrit is also found and requires confirmation on a larger sample.
Abstract: In several groups of subjects with different clinical conditions: vascular atherosclerotic disease (VAD), VAD with diabetes mellitus of type 2 (NIDDM), diabetes mellitus of type 1 and diabetes mellitus of type 2 without macrovascular complications, essential hypertension and chronic renal failure (CRF), we evaluated the red cell Ca2+ content (total and cytosolic), the erythrocyte membrane fluidity and the correlations between them. The total red cell Ca2+ content does not differentiate normals from VAD subjects with and without NIDDM and normals from diabetics of type 1 and 2, but it does discriminate normals from hypertensives and normals from CRF subjects. The…cytosolic red cell Ca2+ content does not distinguish normals from VAD subjects, while it clearly differentiates normals from VAD subjects with NIDDM, normals from diabetics of type 1 and 2, normals from hypertensives and normals from CRF subjects. In all these clinical conditions the erythrocyte membrane fluidity is reduced compared to controls; the erythrocyte membrane fluidity is not related to the total red cell Ca2+ content in each of these clinical conditions, while it is related to the cytosolic red cell Ca2+ content in type 2 diabetics, in hypertensives and in CRF subjects.
Keywords: Total Red Cell Ca2+ Content, Cytosolic Red Cell Ca2+ Content, Erythrocyte Membrane Fluidity
Abstract: The primary effects of steroid hormones are on gene expression, but steroids have also been reported to interact with cellular membranes and affect their properties. The aim of the present study was to elucidate the hemorheological effects of treatment with hydrocortisone. Blood samples from 10 healthy subjects were incubated with Ringer's solution (control) or Ringer's solution + hydrocortisone (10 mg/L). Whole blood viscosity was studied in a rotational viscometer and erythrocyte filterability was measured in the St. George's Filtrometer. Addition of hydrocortisone resulted in a decreased whole blood viscosity (p<0.005), and a deteriorated erythrocyte filterability (p<0.005). An increased concentration of…plasma triglycerides (p<0.02) and plasma total cholesterol (p<0.01) was also found upon addition of hydrocortisone. The concentration of sodium and potassium in plasma did not change. It is concluded that addition of hydrocortisone to concentrations occuring after commonly used therapeutic administration in man produces multiple hemorheological changes. A reduced red cell deformability seems to be balanced by other rheological changes to produce a net reduction of blood viscosity.
Abstract: Cerebral Blood Flow (CBF; 133 Xenon inhalation method) and plasma fibrinogen concentration (radial immunodiffusion) were determined in one hundred and seventy-eight subjects: 1) forty-nine normal subjects, 2) sixty-five vascular risk-factored patients, and 3) sixty-four chronic stroke patients. Due to its strong dependence on age, CBF was also considered as normalized (or z-CBF) values. In each group, both CBF and z-CBF global values (for normal subjects and risk-factored patients) and hemispheric values of the stroke hemisphere were employed for correlations (Pearson's “r”) with plasma fibrinogen. No significant correlation was found between these parameters in any of the groups studied.…These data thus suggest that CBF is independent of plasma fibrinogen concentration, probably due to its autoregulation, in normal subjects as well as in patients prone to develop, or affected with, cerebrovascular disease.
Abstract: We examined whether or not any difference in erythrocyte aggregability (RBC-A) exists between stroke patients with diabetes mellitus and those without diabetes mellitus. The subjects comprised 117 patients at the chronic phase of cerebral infarction (at least 2 months after onset). The patients were divided into two groups: group A, those with cerebral infarction and diabetes mellitus (N=35), aged 60±10 YO (mean±SD); and group B, those with cerebral infarction but without diabetes mellitus (N=82), aged 61±7 YO. For comparison with the erythrocyte aggregability in the stroke patients, we also undertook measurements in 52 age-matched healthy human volunteers (59±9 YO: the…control group) and 44 age-matched patients with diabetes mellitus without macroangiopathy (60±7 YO; the DM group). The erythrocyte aggregability was determined using the whole blood erythrocyte aggregometer developed by us previously (Am J Physiol 251:H1205-H1210, 1986) with concomitant estimation of blood factors such as the hematocrit, albumin:globulin ratio and concentration of fibrinogen. The RBC-A values were 0.164±0.024/s in group A, 0.148±0.024/s in group B, 0.122±0.027/s in the control group and 0.142±0.023/s in the DM group, respectively. The RBC-A values in group A, group B and the DM group were significantly (p<0.01, p<0.01, p<0.01) higher than that in the control group, and the RBC-A value in group A was significantly (p<0.01) higher than that in the DM group. A significant difference (p<0.01) in RBC-A values was noted between groups A and B. Although the values of the hematocrit and albumin:globulin ratio did not differ between groups A and B, the concentration of fibrinogen in group A (350±79 mg/dl) was significantly (p<0.01) higher than that in group B (313±81 mg/dl). The above results suggest that diabetes mellitus exerted a deleterious effect on the patients with cerebral infarction from the hemorheological standpoint.
Abstract: 6 to 17% of kidney recipients develop postrenal transplant erythrocytosis (PTE). As high hematocrit level is often associated with hyperviscosity syndrome, we have studied hemorheological parameters of eight PTE patients. Three methods were applied study of plasma viscosity, erythrocyte (RBC) deformability and RBC aggregation/disaggregation. We did not find any direct correlation between increased hematocrit, hemorheological parameters and thromboembolic complications in PTE patients.