Blood Rheological Parameters Research Articles

Deferoxamine’s Influence on Iron Metabolism, the Rheological Properties of Blood, Endothelial Dysfunction in an Experimental Model of Ischemia/Reperfusion

Objectives. Prevention of violations of microcirculation should take into account the massive entry of hemolysis products into the bloodstream and the related subsequent activation of free radical oxidation. Results. By simulating ischemia/reperfusion on rats we demonstrated the positive effect of deferoxamine on iron metabolism parameters (higher levels of transferrin, less ferritin and free iron, which received the drug group), also observed a decrease in the concentration of von Willebrand factor, as a measure of endothelial dysfunction. Blood viscosity parameters in the deferoxamine group was the closest to the control group parameters. Conclusion. Thus, we can conclude about the positive effect of deferoxamine on the parameters of iron metabolism, microcirculation and blood rheology in critical conditions involving ischemia/reperfusion.

The mechanisms of neuroprotective action of p-tyrosol after the global cerebral ischemia in rats

Aim. The aim of our study is to explore the mechanisms of neuroprotective effects of p-tyrosol in acute global cerebral ischemia-reperfusion in rats. Material and methods. The study was performed on 30 male rats stock Wistar (250–300 g).Animals were divided into 3 groups of 10 rats. In the control and experimental groups we performed the new 3VO model of cerebral ischemia-reperfusion, and the sham-operated animals underwent the same surgical procedures, but without the ligature imposition. Animals in the experimental group received p-tyrosol for 5 days intravenously at a daily dose of 20 mg/kg in a 2% solution. The sham-operated rats and control animals received a isotonic solution of NaCl at the same scheme. We measured rheological blood parameters and the content of products of lipid peroxidation in the brain tissue on the 5th day after cerebral ischemia-reperfusion. Results. Acute ischemia-reperfusion of the brain in rats from the control group caused the significant hemorheological abnormalities, including the increased whole blood viscosity and plasma viscosity, decreased the erythrocyte aggregation half-time and decreased red blood cell deformability index. The increase blood viscosity caused the decrease of the oxygen delivery to the tissues. The content of diene and triene conjugates, fluorescent products and the lipid oxidation index increased in the brain tissue of the control group. These abnormalities induced the death of 50% animals from the control group. Given intravenously to animals of the experimental group, p-tyrosol reduced the whole blood viscosity by 19–31%, the plasma viscosity by 6% and increased the erythrocyte deformability by 31–40%, that led to the increase of oxygen availability for tissues by 21–31% in comparison with the control group. The contents of diene and p-triene conjugates and fluorescent products in the brain tissue under course administration of p-tyrosol decreased respectively by 37%, 49 and 45%, that reflected in the decreasing of lipids oxidation index by 38% in comparison with the control group. The number of survived animals in the experimental group was 1,4 times bigger than in the control group. Conclusion. Course administration of p-tyrosol to rats with acute cerebral ischemia-reperfusion reduces the blood viscosity and the intensity of oxidative stress in the brain tissue. The results of these effects are the reduction of negative outcomes of ischemia-reperfusion of the brain and the increasing of animal surviving, that confirms the neuroprotective action of p-tyrosol in these conditions.

Effects of Modified Qing'e Pill () on expression of adiponectin, bone morphogenetic protein 2 and coagulation-related factors in patients with nontraumatic osteonecrosis of femoral head.

To observe the regulation of Chinese herbal medicine, Modifified Qing'e Pill (, MQEP), on the expression of adiponectin, bone morphogenetic protein 2 (BMP2), osteoprotegerin (OPG) and other potentially relevant risk factors in patients with nontraumatic osteonecrosis of the femoral head (ONFH). A total of 96 patients with nontraumatic ONFH were unequal randomly divided into treatment group (60 cases) and control group (36 cases). The treatment group were treated with MQEP while the control group were treated with simulated pills. Both groups were given caltrate D. Six months were taken as a treatment course. Patients were followed up every 2 months. The levels of plasma adiponectin, BMP2, OPG, von Willebrand factor (vWF), von Willebrand factor cleaving protease (vWF-cp), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (tPA), C-reactive protein (CRP), blood rheology, bone mineral density (BMD) of the femoral head and Harris Hip Score were measured before and after treatment. After 6 months of treatment, compared with the control group, patients in the treatment group had signifificantly higher adiponectin and BMP2 levels (P<0.01 and P=0.013, respectively), lower vWF, PAI-1 and CRP levels (P=0.019, P<0.01 and P<0.01, respectively), and lower blood rheology parameters. BMD of the femoral neck, triangle area and Harris Hip Score in the treatment group were signifificantly higher than those in the control group. Moreover, plasma adiponectin showed a positive association with BMP2 (r=0.231, P=0.003) and a negative association with PAI-1 (r=-0.159, P<0.05). MQEP may play a protective role against nontraumatic ONFH by increasing the expression of adiponectin, regulating bone metabolism and improving the hypercoagulation state, which may provide an experimental base for its clinical effects.

Protective effects of traditional Tibetan medicine Zuo-Mu-A Decoction () on the blood parameters and myocardium of high altitude polycythemia model rats.

To explore the protective effects of Tibetan medicine Zuo-Mu-A Decoction (, ZMAD) on the blood parameters and myocardium of high altitude polycythemia (HAPC) model rats. Forty male Wistar rats were randomly divided into 4 groups by a random number table, including the normal, model, Rhodiola rosea L. (RRL) and ZMAD groups (10 in each group). Every group was raised in Lhasa to create a HAPC model except the normal group. After modeling, rats in the RRL and the ZMAD groups were administered intragastrically with RRL (20 mL/kg) and ZMAD (7.5 mL/kg) once a day for 2 months, respectively; for the normal and the model groups, 5 mL of distilled water was administered intragastrically instead of decoction. Then routine blood and hematologic rheology parameters were taken, levels of erythropoietin and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were tested, and ultrastructural change in the left ventricular myocardium was observed using transmission electron microscopy. Compared with the model group, ZMAD significantly reduced the red blood cell count, hemoglobin levels, whole blood viscosity at low/middle shear rates, plasma viscosity, erythrocyte electrophoretic time, erythropoietin and 8-OHdG levels, and also increased the erythrocyte deformation index (P<0.05). There was no difference in all results between the RRL and the ZMAD groups. The cardiac muscle fibers were well-protected, mitochondrial matrix swelled mildly and ultrastructure changes were less prominent in the ZMAD group compared with the model group. ZMAD has significant protective effects on the blood parameters against HAPC, and also has the beneficial effect in protecting against myocardial injury.

Evaluation of blood prothrombotic parameters under the influence of physical activity

Introduction. Blood is a suspension of cellular components in plasma. Its viscosity is affected by haematocrit, the aggregation ability of erythrocytes and the viscosity of plasma, conditioned by high-molecular fibrinogen proteins or lipoprotein. The increase of blood viscosity occurs in the course of many diseases leading to the formation of atherosclerotic lesions. Material and methods. The study involved 50 patients with femoral-popliteal type of occlusion in stage IIB according to Fontaine’s classification. Before the training, the patients underwent a treadmill test evaluating claudication distance. The proposed training included physical exercise performed 3 times a week and lasting 30 minutes for a period of 6 months. Before and after the training, venous blood samples for laboratory tests were taken to determine the values of haematocrit, haemoglobin, as well as phosphatase and calcium D-dimers. The purpose of the study was to evaluate the impact of training on selected blood rheological parameters. In addition, the change in BMI values and the length of distance of relative claudication were evaluated in the prospect of changes in laboratory values. Results. The applied training contributed to the reduction of selected blood parameters. Statistical significance was observed at p < 0.0001 for D-dimers, haematocrit and phosphatase. The changes in BMI values were reflected in the results of D-dimers and phosphatase. A statistical significance also occurred in the case of the extension of claudication distance and changes in the values of D-dimers, haematocrit and phosphatase. Conclusions. The supervised training had an impact on the reduction of prothrombotic blood parameters. Health-oriented physical exercise can contribute to body weight decrease and painless distance extension.

Correlation between blood rheological properties and red blood cell indices(MCH, MCV, MCHC) in healthy women.

Structure and mechanical properties of red blood cells are markedly influenced by pathophysiology of many diseases which in turn potentially impair microcirculatory blood flow. The physiological association between blood rheological parameters and red blood cell indices was investigated in otherwise healthy unselected mid-age women prior to elective gynaecological surgery. Red Blood Cell-deformability (RBC 1.2, 3.0; 6.0, 12.0; 30.0, 60.0) during exposure to low (RBC 1.2, 3.0), moderate (RBC 16.0, 12.0) and high shear forces (RBC 30.0, 60.0; Rheodyn; Myrenne), -aggregation (MA1; Myrenne) during low shear (E1; 4-1 S) and in stasis (E0) and plasma viscosity (Pv; KSV 1; Fresenius) were correlated with red blood cell indices (RBC-I: MCV, MCH and MCHC) and subjects' characteristics in 286 healthy women the day before undergoing gynaecologic standard surgery. Women with known pregnancy, malign-, infective-, chronic-disease or extreme BMI (<16; >40 Kg/m2) were excluded from this trial. From June 2014 to December 2014 a total of 286 healthy women (age: 46.5±17.6 y; BMI: 25.5±5.2 kg/m2) were eligible for inclusion into this prospective evaluation. Pv (mean±SD: 1.17±0.12 mPa s) and RBC aggregation (E0:12.6±6.3; E1:17.9±7.3) were not significantly correlated with RBC-I but with age and BMI. In contrast, RBC-deformability correlated significantly with MCV and MCH but significantly inversely correlated with MCHC. Deformability significantly increased with age but was unaffected by BMI of women. The correlation between RBC-I and RBC deformability was most remarkable during moderate shear force exposure. Neither haemoglobin nor haematocrit were correlated with RBC deformability or RBC-I. Cell volume and haemoglobin content had a strong impact on deformability in apparently healthy mid age women, whereas low MCHC and large MCV were associated with an increase in deformability while high MCHC and small MCV correlated with increased rigidity of RBC. BMI had no impact on deformability while age was associated with an increase in all determinants of blood viscosity. RBC aggregability was not affected by MCV, MCHC or MCH in mid-age women.

THE INFLUENCE OF PHOTOHAEMOTHERAPY ON BLOOD RHEOLOGY IN BRONCHIAL ASTHMA

Background: Blood rheology abnormalities are recognized as one of the main pathophysiological components of bronchial asthma. Standard medical treatment of bronchial asthma does not exert any substantial effect on blood fluidity. Aim: To assess efficacy of quantum haemotherapy and its influence on blood rheology in the combination treatment of bronchial asthma. Materials and methods: Four hundred and eighty patients admitted to our in-patient department with mild (44.5%) and severe (55.5%) exacerbations of persistent moderate asthma, were randomized into two groups: the main group (n = 250), which, along with conventional treatment, received photohaemotherapy with blue (PHB, n = 220) or red (PHR, n = 30) light, and the control group (n = 230), which received conventional treatment for two weeks. PHB (light-emitting diode devise “Solaris”) and PHR (helium neon laser) was performed according to the following regimen: duration of a session 30 minutes, number of sessions, from 5 to 7 with in-between intervals of 2 to 3 days. The degree of erythrocyte deformation, relative membrane charge and relative gradient membrane potential of erythrocytes, total erythrocyte counts, hemoglobin levels, hematocrit, and blood viscosity were assessed at days 1 and 14, as well as after 3 months. Results: At day 14, the relative gradient membrane potential of erythrocytes decreased to 0.118 ± 0.01 r.u. in the PHB group, to 0.167 ± 0.01 r.u. in the PHR group, and to 0.153 ± 0.01 r.u. in the conventional treatment group. The relative charge of erythrocyte membranes increased to 0.202 ± 0.07, 0.19 ± 0.07 and 0.14 ± 0.07 r.u., the degree of erythrocyte deformation decreased to 1.4 ± 0.1, 1.6 ± 0.1 and 1.9 ± 0.1 scores, the degree of hypoxic anisotropy of the serum decreased to 0.8, 0.9 and 1.2 scores, respectively (in all cases, p 0.05). At month 3, all patients, despite their clinical well-being, demonstrated a deterioration of the parameters studies. However, only in the conventionally treated group the degree of this deterioration was compatible with parameters registered during an asthma exacerbation. Conclusion: Blood rheology parameters demonstrated a more rapid and advanced improvement in patients with exacerbations of bronchial asthma, who were treated with the use of photohaemotherapy, compared to those who received conventional treatment only.

OPTIMAL USE OF BETA-BLOCKERS IN CASE OF CHRONIC HEART FAILURE

Objective – review current data on the use of beta-blockers (BB) in chronic heart failure (CHF). Materials and methods. This article discusses beneficial effects of BB administration in CHF patients. It has been demonstrated that decrease in heart rate underlies clinical efficacy of BB therapy in patients with chronic heart failure. We reviewed the question of the necessity to achieve target doses of BB in the treatment of CHF patients. It has been shown that administration of BB in patients with chronic heart failure and reduced left ventricular ejection fraction increase pumping function of heart, and thus reduce the number of hospitalizations for decompensated heart failure, reducing the risk of total and sudden mortality. We demonstrated substantial advantages of β1-selective BB over nonselective ones with respect to their impact on hemodynamics, metabolic processes, rheological parameters of blood and bronchi. We also considered therapeutic tactics in case of BB administration in CHF patients. Results. Based on the data of the current studies we proved high efficiency and safety of β1-selective BBs in CHF patients. Conclusion. Correct choice of BB in patients with CHF and decrease in heart rate during the treatment can significantly increase an effectiveness of the treatment.

Современные взгляды на этиопатогенез инфаркта миокарда при сахарном диабете 2 типа и методы лечения (обзор литературы)

This paper is devoted to an actual problem in cardiology and endocrinology, a problem of combined interaction of myocardial infarction and diabetes mellitus, which represent a serious medical and social significance. It is noted that fatal myocardial infarction in patients with diabetes mellitus is significantly higher than in patients without diabetes, regardless of the time of follow-up period. The authors note the importance of improvement the efficiency of complex treatment of acute myocardial infarction by correction of metabolic, blood rheological and microcirculatory parameters in patients with diabetes mellitus in combination with the total myocardial revascularization. This article highlights the epidemiology of diabetes mellitus, pathogenesis of myocardial infarction in patients with diabetes mellitus. The authors represent modern ideas of microcirculation disorders and pathophysiology of atherosclerosis and diabetes mellitus. Based on the pathophysiological model of diabetes, the authors reflect current approaches to the treatment of acute myocardial infarction. In con-clusion, the authors emphasize the need for an integrated approach to optimize the treatment algorithms and prognosis of myocardial infarction in patients with diabetes mellitus, to improve the nearest and long-term re-sults of percutaneous coronary intervention and coronary artery bypass grafting by the correction of metabolic disorders, blood rheology and lipid peroxidation.

Salvia miltiorrhiza prevents deep vein thrombosis via antioxidative effects in endothelial cells.

Deep vein thrombosis (DVT) is a common clinical problem, which represents a significant clinical and economic burden. The present study investigated whether Salvia miltiorrhiza (S. miltiorrhiza) could prevent DVT. A total of 30 rabbits were randomly divided into three groups (n=10 per group): The control, model and Salvia groups. A ligation model was used, where the femoral veins of rabbits were exposed and ligated. Measurements of coagulation function, blood rheological parameters, antioxidative function and effects on endothelial cells were conducted. Treatment with S. miltiorrhiza one week prior to generation of the ligation model did not affect the coagulation function much, except to increase the prothrombin time. There was a statistically significant difference (P<0.05) in whole blood viscosity (1/s, 5/s, 30/s) on the third and seventh days (1/s, 5/s, 30/s and 200/s) following generation of the model. S. miltiorrhiza exhibited promising antioxidative effects, as demonstrated by a significant decrease in malondialdehyde content (P<0.05), and an increase in the activities of superoxide dismutase (P<0.05), as compared with the model group. S. miltiorrhiza was also shown to protect the vascular endothelial cells, as compared with the model group. These results suggest that S. miltiorrhiza may have potential applications for the treatment of DVT.

Rheologic results and their correlation to hemostatic changes in patients with moderate and severe preeclampsia: An observational cross-sectional study

Previous study have shown an association between failure of physiological hemodilution during 2nd trimester and an increased risk for the development of subsequent pregnancy complications such as early birth, birth of a growth retarded newborn (IUGR), low fetal birth weight and preeclampsia. The latter complication in particular goes along with dramatic changes in the placental perfusion as well as systemic maternal blood flow. Severity of preeclampsia may be preceded by distinct impaired hemodilution and reflected by the results of rheological parameters. A subgroup analysis was performed in a community based retrospective study of 4,985 consecutively recorded singleton pregnant women of whom 423 had preeclampsia. Mean 2nd trimester hemoglobin levels and blood rheological results at the time of delivery were assessed and compared in women with moderate and severe preeclampsia. Mean 2nd trimester hemoglobin levels were calculated from the maternal records. Rheological variables included plasma viscosity (KSPV 1 Fresenius) and Red blood cell aggregation in stasis and under low shear conditions (MA1-Aggregometer; Myrenne). According to the definition of the German Society of Gynecology and Obstetrics (DGGG) 314 women had moderate preeclampsia (74.2%), while 109 had severe preeclampsia due to the presence of a blood pressure>170/110 mmHg (n=41; 9.7%), and/or IUGR<5th percentile (n=28; 6.6%), and/or HELLP-Syndrome (n=10; 2.4%), and/or proteinuria≥5 g/24 h (n=30; 7.1%). Age, BMI, smoking, and maternal weight were comparable in the groups, while gestational age at delivery as well as fetal outcome parameter were statistically significant unfavourable in patients with severe preeclampsia. Mean 2nd trimester hemoglobin level were statistically significantly higher in women who developed severe vs. moderate preeclampsia (m=12.75±0.99 g/dL vs. m=12.50±1.05 g/dL; p=0.033). However, in the ROC calculations a hemoglobin value of 12.05 g/dL revealed best sensitivity (78%) and specificity (33.8%) in women with subsequent diagnosis of severe preeclampsia, whereas sensitivity was 100% for a value>10.95 g/dL. There were no statistically significant differences for none of the rheological parameters at the time of delivery between groups of patient with moderate v.s severe preeclampsia. Severe preeclampsia and IUGR, however, was associated with statistically significantly higher RBC aggregation as compared to patients with moderate preeclampsia. Plasma viscosity was statistically significantly (p<0.05) correlated with Fibrinogen values (r=0.16), leukocyte-(r=0.11) and platelets-count (r=0.127), and hemoglobin/hematocrit values in particular (r=0.23/0.26). Although mean 2nd trimester hemoglobin concentration are higher in patients with subsequent development of severe preeclampsia, due to the low sensitivity and specificity of this parameter clinical use for identifying women at risk is of limited value. On the other hand, a hemoglobin value below 11.0 g/dL excluded the risk for severe preeclampsia to 100%. Blood rheological parameters at the time of delivery in the absence of IUGR are not markedly influenced by severity of preeclampsia.

Антиагрегационное влияние сосудистой стенки на основные форменные элементы крови у телят в фазу молочного питания

Blood cell aggregation is known to influence significantly a blood rheology in animals, particularly in cattle, during each period of ontogenesis, of which the milk feeding is important for development of a number of physiological mechanisms, including effective vascular control of gemostasis. Here we report the results of studying effect of vascular walls to blood cell aggregation in 39 Black-and-White calves. Blood samples were analyzed in 11, 15, 20 25 and 30 day old animals. A lipid peroxidation was estimated based on thiobarbiturate concentration (TB), the parameters of antioxidation activity in blood plasma were assessed, and antiaggregation properties of the blood vessels were investigated in the test of vein occlusion. Erythrocyte aggregations, free erythrocytes and the number of erythrocytes per aggregation were counted. Also the formation of platelet and neutrophil aggregations was considered. There were calculated the indexes of vascular control of erythrocyte number per aggregation, aggregation number, and free erythrocyte number. Also the antiaggregation activity of blood vessel wall and an inhibition of neutrophil aggregation by vascular wall were indexed. During investigation the lipid peroxidation in calves’ blood plasma was low, the acyl hydro-peroxide level varied from 1.44±0.17 to 1.47±0.25 D 233/ml, and the concentration of TB-active compounds changed from 3.59±0.15 to 3.64±0.28 mmol/l, with an antioxidation activity changed slightly too. An increase was shown of blood cell aggregating coupled with a gradually growing antiaggregation effect of vascular wall due to activated N-oxide and prostacyclin production in the endothelium. A balance of observed proand antiaggregation activity provides optimal rheological blood parameters in milk-fed calves resulting in adaptation to the environmental factors.

Correlation of rheological parameters in maternal and fetal blood at term

Objective: An association between maternal and fetal blood rheology has not yet been investigated nor is it known whether and to what extent fetal blood rheology may be affected by maternal conditions.Methods: At delivery, blood was drawn from the cubital vein of 4985 consecutive mothers and from the umbilical cord during birth for determination of blood rheological parameters (erythrocyte aggregation stasis [E0], low shear [E1], plasma viscosity [Pv]) in addition to hemoglobin (Hb) values and hematocrit (Hct).Results: Maternal and newborn Pv (r = 0.2; p < 0.0001) correlated statistically significant. There was a remarkable correlation between fetal Pv and gestational age (r = 0.197; p < 0.001). Iron supplementation during pregnancy led to increased fetal Hb, Hct as well as E0 and E1 (p < 0.0001), did not have a significant impact on neonatal Pv (p = 0.068). Smoking mothers gave birth to neonates with significantly higher Pv (p = 0.049), E0 (p = 0.016) and E1 (p = 0.013).Conclusions: The increase of fetal plasma viscosity at advanced delivery time-points refers to a more gaining protein synthesis by the fetal liver and thus maturity of the fetus. Iron supplementation as well as smoking during pregnancy is associated with a relative hyper-viscosity in the fetus at delivery.

Yield shear stress and disaggregating shear stress of human blood

This review presents two distinct rheological parameters of blood that have the potential to indicate blood circulation adequacy: yield shear stress (YSS) and disaggregating shear stress (DSS). YSS and DSS reflect the strength of red blood cell (RBC) aggregation in suspension under static and dynamic conditions, respectively. YSS, defined as the critical stress to disperse RBC aggregates under static conditions, was found to be dependent upon hematocrit, fibrinogen, and red cell deformability, but not temperature. DSS, defined as the minimum shear stress to disperse RBC aggregates under dynamic conditions, is dependent upon fibrinogen, red cell deformability, and temperature but not hematocrit. Owing to recent advances in measurement technology, these two parameters can be easily measured, and thus, their clinical significance in blood circulation can be verified.

The effect of lead-induced oxidative stress on blood viscosity and rheological properties of erythrocytes in lead exposed humans

Lead-induced oxidative stress has been identified as the essential factor in lead poisoning pathogenesis. Therefore, the present study examined the association between occupational lead exposure and blood rheological parameters with respect to malondialdehyde (a lipid peroxidation product), lipofuscin, and glutathione concentrations in erythrocytes. The examined group included 283 healthy male employees of lead-zinc works. In brief, 129 workers were classified as the low-exposure group, while the high-exposure group was composed of 154 workers. The mean blood levels of lead and zinc-protoporphyrin and the mean urine concentrations of delta-aminolevulinic acid were used as exposure markers. The control group consisted of 73 healthy male administrative workers. Whole blood viscosity was elevated in both exposure subgroups compared with the control group. Erythrocyte aggregability increased significantly; although the increase was greater in the low exposure group. Erythrocyte deformability decreased in both subgroups. The levels of malondialdehyde and lipofuscin were significantly elevated, whereas the glutathione content decreased. In conclusion, occupational exposure to lead may induce oxidative stress in erythrocytes. This stress elevates whole blood viscosity and disturbs erythrocyte aggregability and deformability. There is a dose-effect relationship between lead levels and blood rheological parameters.

The effect of pulsed IR-light on the rheological parameters of blood in vitro.

In this study we attempted to assess the effect of light of 855 nm wavelength (IR-light) on the rheological parameters of blood in vitro. As an anticoagulant, heparin was used. The source of IR-light was an applicator connected to the special generator--Viofor JPS®. The blood samples were irradiated for 30 min. During the irradiation the energy density was growing at twelve-second intervals starting from 1.06 J/cm2 to 8.46 J/cm2, then the energy density dropped to the initial value; the process was repeated cyclically. The study of blood viscosity was carried out with a Contraves LS40 oscillatory-rotational rheometer, with a decreasing shearing rate from 100 to 0.01 s⁻¹ over 5 min (flow curve) and applying constant frequency oscillations f=0.5 Hz with decreasing shear amplitude ˙γ0 (viscoelasticity measurements). The analysis of the results of rotational measurements was based on the assessment of hematocrit, plasma viscosity, whole blood viscosity at four selected shear rates and on the basis of the numerical values of parameters from Quemada's rheological model: k0 (indicating red cell aggregability), k∞ (indicating red cell rigidity) and ˙γc (the value of the shear rate for which the rouleaux formation begins). In oscillatory experiments we estimated viscous and elastic components of the complex blood viscosity in the same groups of patients. We observed a decrease of the viscous component of complex viscosity (η') at ˙γ0=0.2 s⁻¹, while other rheological parameters, k0, k∞, and relative blood viscosity at selected shear rates showed only a weak tendency towards smaller values after irradiation. The IR-light effect on the rheological properties of blood in vitro turned out to be rather neutral in the studied group of patients.

Effects of a meal on the hemorheologic responses to exercise in young males.

Aim. This study investigates the changes in hemorheologic parameters resulting from exercise followed by a standard meal. Methods. In twelve moderately active men a period of exercise on a bicycle ergometer for 30 min at 60% VO2max was followed by a test meal or by 30 min rest. Venous blood was sampled for further analysis at baseline, after exercise, and after the meal/rest period. Results. The elongation index (EI) was reduced and a marked rise in plasma viscosity was observed after exercise. A significant decrease in half time of total aggregation (T 1/2) and a rise in aggregation index (AI) after exercise were observed; however, after the postexercise period these changes were reversed. Conclusion. The present study demonstrates that physical exercise causes several changes in blood rheology parameters, such as an increase of blood viscosity, a decrease in EI and an increase in AI, and a fall in the T 1/2 values. The meal eaten in the postexercise period caused a further reduction in EI values indicating higher red cell rigidity, but not in plasma viscosity or aggregations indices. Such alterations in hemorheologic parameters should not impair the function of the cardiovascular system in fit and healthy people but it could constitute a serious risk under various pathophysiological conditions.

Effects ofMomordica charantiaL. on the Blood Rheological Properties in Diabetic Patients

An evaluation of the rheological properties and the effects of Momordica. charantia L. (M. charantia) nanoparticles and polyethylene glycol (PEG) microspheres adsorbed with M. charantia nanoparticles on the blood of hyperglycemic patients is presented. Blood samples were collected according to glycemic status: normoglycemic (N = 56) and hyperglycemic (N = 26). General and hematological characteristics were determined. Blood rheological parameters were determined at room temperature and under a temperature scan. We determined the effects on whole blood viscosity of treatment with an extract of M. charantia, PEG, or PEG microspheres adsorbed with plant extract. The viscosity of the blood of hyperglycemic patients is greater than that of normoglycemic patients. Nanoparticles of M. charantia extracts lowered blood viscosity at equivalent rates in normo- and hyperglycemic individuals. PEG microspheres did not reduce blood viscosity in hyperglycemic individuals. However, PEG microspheres adsorbed with nanofraction extracts of M. charantia reduced blood viscosity. These data suggest that the effects of diabetes on the viscosity of the blood should be considered. The use of a nanoparticles extract of M. charantia and its adsorption on PEG microspheres may represent an alternative for the control and treatment of blood disorders in diabetic patients.

Effect of heat stress on blood rheology in different pigs breeds

The main objectives of the present work were to test the effects of heat stress on blood rheology and to determine whether the responses can change according to the pig breeds. Thirty-six pigs from three pig's lines (n = 12 for each line) with assumed different tolerance to heat stress were compared: Large White (LW, little tolerance), Creole (CR, good tolerance) and LW × CR pigs (produced from a cross between LW and CR lines). In a first period, all pigs were exposed to a 9-d period of thermo-neutral environment (24°C; d-9 to d-1; P0). At the end of P0, six pigs from each line were slaughtered (n = 18). Then in a second period, the remaining pigs (6/breed; n = 18) were exposed to a 5-d period of heat stress (32°C; d + 1 -d + 5; P1) and thereafter slaughtered at d + 5. Rectal and skin temperatures, as well as respiratory rate, were recorded on d-1 and d + 5. At slaughter, blood was sampled for hematological and hemorheological measurements. Heat stress caused a rise of the skin temperature and respiratory rate without any changes in the rectal temperature or on the hematological and hemorheological parameters when all pigs' lines were considered. We observed a pig line effect on blood viscosity at high shear rate (375 s-1) and red blood cell deformability at 30 Pa with CR pigs having lower blood viscosity and higher red blood cell deformability than LW pigs. While the changes of blood viscosity under heat stress did not reach statistical significance in LW and CR lines, blood viscosity (at 375 s-1) increased above the temperate values in the LW × CR line. Red blood cell deformability at 30 Pa was higher in CR pigs exposed to heat stress compared to LW pigs in the same condition. In conclusion, thermal loading caused physiological stress but did not widely change the hematological and hemorheological profiles. Although some blood rheological parameters seem to vary with the pig breeds, the responses to heat stress are very similar.

THE RHEOLOGICAL PROPERTIES OF BLOOD IN THE MOST ACUTE STAGE OF ISCHEMIC STROKE AND THEIR RELATION TO THE SEVERITY OF NEUROLOGICAL IMPAIRMENT

The study evaluated the rheological parameters of blood: blood viscosity, plasma viscosity, hematocrit, red blood cell aggregation and deformability. The severity of the patients was assessed by clinical scales:Glasgowcoma scale, the scale NIHSS, Barthel index. The study found that in the acute phase of ischemic stroke increased blood viscosity by increasing red blood cell aggregation and reduced erythrocyte deformability. The increase in the viscosity of the blood in acute ischemic stroke is accompanied by increased severity of neurological disorders.