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Results for “BLOOD VISCOSITY”

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At least 397 records · Page 22Linked to original sources
PubMed1996

Nutritional antioxidants, red cell membrane fluidity and blood viscosity in type 1 (insulin dependent) diabetes mellitus.

The study was designed to evaluate whether the antioxidant nutrients selenium, vitamin A, and vitamin E are associated with alterations of blood viscosity in patients with insulin-dependent (Type 1) diabetes mellitus (IDDM). We assessed selenium concentrations in plasma and red blood cells (RBC), glutathione peroxidase activity in RBC, vitamin A and vitamin E, and the viscosity of whole blood and plasma in 20 patients with IDDM and 20 sex, age and body mass index-matched healthy controls. While selenium was not altered in plasma in IDDM, it was markedly decreased in RBC of IDDM (1.24 +/- 0.32 vs 0.92 +/- 0.38 mumol l-1, p = 0.006) correlating negatively with the elastic and viscous component of whole blood viscosity. Plasma viscosity increased with stage of retinopathy. Mean glutathione peroxidase activity in RBC was reduced in IDDM (5.78 +/- 0.77 vs 5.13 +/- 1.03 U gHb-1, p = 0.029). In IDDM with normal renal function (creatinine < or = 97.2 mumol l-1, no albuminuria) vitamin A was significantly reduced (1.26 +/- 0.62 vs 1.89 +/- 0.56 mumol l-1, p = 0.005). Vitamin A levels increased with impaired renal function. They strongly correlated with plasma creatinine (r = 0.86, p < 0.001) and plasma viscosity (r = 0.71, p = 0.001). However, in vitro experiments with different vitamin A plasma concentrations indicated that this particular correlation may not represent a causal one. No changes in vitamin E were found in IDDM. We conclude that reduced selenium concentrations in RBC contribute to impaired haemorheology in IDDM patients. Plasma viscosity was not affected by the plasma concentrations of vitamins A and E.

Adult↗
PubMed2003

Variations of whole blood viscosity using Rheolog-a new scanning capillary viscometer.

BACKGROUND: Whole blood viscosity (WBV) values identify subjects at high risk for initial or recurrent cardiovascular events. However, these measurements have been limited to specialized centers. A new type of viscometer, Rheolog, was designed to overcome the difficulties encountered in WBV measurements using the standard rotational viscometer in a clinical environment. METHODS: We evaluated the 14-day variability of WBV measured by Rheolog in a single-center study of 24 healthy male subjects aged 18-75 years. WBV was measured through an 11-h period on study days 1, 8, and 14. An additional fasting WBV test was performed on study days 3, 5, and 11. RESULTS: Average morning measurements were higher than afternoon measurements at all shear rates. Both inter- and intraindividual variations were higher in the morning than later in the day, but the differences between pooled mean values were not significant. Interindividual variations at fasting were higher than the pre-meal or overall variations. There was a small nonsignificant increase in mean viscosity following each meal. CONCLUSION: WBV measurements using Rheolog have potential for clinical application because of the convenience and low variability of measurements over time.

Adolescent↗
PubMed1997

[Blood viscosity disorders as an etiopathological factor in sudden deafness].

Because idiopathic sudden deafness is regarded as the result of a cochlear microcirculation disorder, its treatment has been based mainly on vasoactive therapy with little regard for the blood-flow conditions produced by these circumstances. In a group of 16 patients with sudden-onset deafness, we determined blood viscosity at different shear rates, as well as erythrocyte aggregability, deformability, and filterability, and other potentially influential parameters, such as hematobrit, fibrinogen, and leukocyte and platelet count. These values correlated with hearing loss and average recovery after conventional treatment. Our results showed a trend to high blood viscosity in patients in relation to a control group of persons with normal hearing, with a notorious increase in aggregability, which correlated significantly with recovery of hearing capacity, and a decrease in blood filterability, which correlated with average hearing loss. This suggests a potential etiopathogenic mechanism of the disease and an alternative treatment complementary to current treatment.

Anti-Inflammatory Agents↗
PubMed1981

[Blood viscosity. Measurement and applications (hyper--and hypoviscosity syndromes) (author's transl)].

Blood has particular rheological properties which partly condition its flow, especially in capillary vessels, and its ability to deliver oxygen. It is not subject to gravitation, pseudoplastic, thixotropic and visco-elastic. Blood viscosity depends upon macroscopic factors, such as erythrocyte aggregation and deformability. Hyperviscosity is observed in cases of increased haematocrit (polycythaemia and relative polycythaemia), increased serum proteins and changes in protein balance (e.g. rise in fibrinogen and immunoglobulins, fall in albumin) as seen in inflammation and dysglobulinaemia, drop in temperature (hypothermia), increased erythrocyte aggregation (shock, fat embolism) or imparied deformability due to various acquired or inherited disorders of red cell membrane or cytoplasma (e.g. sickle cell anaemia, renal failure, hyperlipoproteinaemias, thrombosis, diabetes). The various factors may be combined, as in diabetes. Conversely, hypoviscosity may result from decreased haematocrite, fall in blood proteins and fibrinogen, or hyperthermia. Hyperviscosity can be corrected by acting on its various constituents. Treatments include haemodilution, plasmapheresis, anti-aggregants and drugs improving red cell deformability.

Blood Proteins↗
PubMedDate not supplied

Decrease in whole blood viscosity in alloxan diabetic rabbits.

Whole blood and plasma viscosity of normal and alloxan diabetic rabbits were measured by means of cone in cone viscosimeters at different shear rates. Blood behaves like a non-Newtonian fluid, i.e. the viscosity is shear rate-dependent whereas plasma viscosity remains constant over the shear rate range employed, i.e. behaves like a Newtonian fluid. Blood viscosity was found to be statistically significantly decreased in the alloxan diabetic group in comparison to the control group. The decrease is attributed to a slight decrease in mean hematocrit and mean plasma viscosity of the diabetic animals. The possible mechanisms of these changes are discussed.

Animals↗
PubMed2002

[Effects of refined konjac meal on lipid metabolism and blood viscosity of rats fed by high fat forage].

Male SD rats are fed by high fat diet supplemented with refined konjac meal for 6 weeks and the effect of refined konjac meal on the serum lipid peroxides (LPO) and blood viscosity are observed. The results showed that the refined konjac meal can obviously decrease serum cholesterol, triglyceride and serum LPO of rats in comparison with those of rats fed only by high fat forage, and can elevate, at the same time, the high density lipoprotein-cholesterol and high density lipoprotein-cholesterol/triglyceride value. It is also shown that the refined konjac meal can decrease the blood viscosity, but has no effect on forage intake and weight gain of rats.

Animals↗
PubMed1975

[Changes in plasma and whole blood viscosity during starvation (author's transl)].

More than 6000 parameters were collected during a 21-day period of starvation in 51 obese patients aged 17 to 65 years and stored as data bank on a CDC CYBER 74 at the calculating centre of the University of Technology in Vienna. Samples for multiple linear regression were obtained on the basis of various selective criteria. The essential results of this analysis are the depression of plasma viscosity, which correlates positively with the decrease in blood lipids and the reduction of overweight, as well as the unexpected increase in whole blood viscosity. The latter can probably be explained by an altered erythrocytic fluidity due to the metabolic changes which take place during a longer period of starvation.

Adolescent↗
PubMed1990

[Relationship among blood pressure, viscosity of blood and cerebro-vascular disease].

In this article, 163 cases of hypertension patients and 117 cases of stroke patients with acute period including 43 cases of hemorrhagic strokes and 74 cases of ischemic strokes were analyzed between average arterial blood pressure and blood viscosity. The curves of relation of blood pressure versus blood viscosity in the hypertension patients' group showed "M" shape. The hemorrhagic stroke patients were located by up-side of the "M" shape curve and the ischemic stroke patients were situated by the down-side of the "M" shape curve.

Aged↗
PubMed1990

[Changes in blood viscosity and erythrocyte deformability in patients with dyslipidemia treated with binifibrate].

31 patients afflicted with primary hyperlipidemia who did not improve after 30 days on a diet were treated with 1800 mg/day of binifibrate. We measured the total cholesterol level and triglyceridemia, as well as blood viscosity and red cell deformability at day 0, 30, 60, 90 of treatment. We found a statistically significant decrease in cholesterol and triglyceride levels as well as blood viscosity, and an increment of red cell deformability which improved the circulatory dynamisms augmentin the tissular perfusion in these patients.

Aged↗
PubMed1985

Is maternal whole blood viscosity a factor in fetal growth?

Many authors have correlated changes in maternal hemodynamics during pregnancy with fetal growth. Sufficient plasma volume expansion in pregnancy seems mandatory for an optimal reproductive result. A correlation between rheological characteristics (low-shear whole blood viscosity and yield shear stress) and birthweight centiles was found in 26 third-trimester pregnancies. The level of statistical significance (P less than 0.05) was reached in nulliparous pregnancies but not in parous pregnancies. Measurements of whole blood viscosity at low shear rate and yield shear stress seem to provide information on the efficacy of placental perfusion. There have been reports in the literature to support the assumption of the prevalence of low-shear circumstances in the intervillous space. The hypothesis is put forward that, during pregnancy, the changes in maternal hemodynamics influence fetal growth by their impact on the flow through the placenta.

Adult↗
PubMed1997

The effects of low-density lipoprotein and high-density lipoprotein on blood viscosity correlate with their association with risk of atherosclerosis in humans.

1. Increased blood or plasma viscosity has been observed in almost all conditions associated with accelerated atherosclerosis. Cognizant of the enlarging body of evidence implicating increased viscosity in atherogenesis, we hypothesize that the effects of low-density lipoprotein and high-density lipoprotein on blood viscosity correlate with their association with risk of atherosclerosis. 2. Blood viscometry was performed on samples from 28 healthy, non-fasting adult volunteers using a capillary viscometer. Data were correlated with haematocrit, fibrinogen, serum viscosity, total cholesterol, high-density lipoprotein-cholesterol, triglycerides and calculated low-density lipoprotein-cholesterol. 3. Low-density lipoprotein-cholesterol was more strongly correlated with blood viscosity than was total cholesterol (r = 0.4149, P = 0.0281, compared with r = 0.2790, P = 0.1505). High-density lipoprotein-cholesterol levels were inversely associated with blood viscosity (r = -0.4018, P = 0.0341). 4. To confirm these effects, viscometry was performed on erythrocytes, suspended in saline, which had been incubated in plasma of various low-density lipoprotein/high-density lipoprotein ratios. Viscosity correlated directly with low-density lipoprotein/high-density lipoprotein ratio (n = 23, r = 0.8561, P < 0.01). 5. Low-density lipoprotein receptor occupancy data suggests that these effects on viscosity are mediated by erythrocyte aggregation. 6. These results demonstrate that the effects of low-density lipoprotein and high-density lipoprotein on blood viscosity in healthy subjects correlate with their association with risk of atherosclerosis. These effects on viscosity may play a role in atherogenesis by modulating the dwell or residence time of atherogenic particles in the vicinity of the endothelium.

Adult↗
PubMed1990

Effects of pentoxifylline administration on blood viscosity and leukocyte cytoskeletal function in patients with intermittent claudication.

We have previously shown that pentoxifylline, a drug used in intermittent claudication, causes depolymerization of actin in leukocytes in vitro. In this study we evaluated several parameters in peripheral blood obtained from 17 patients receiving pentoxifylline, before therapy and at 1 and 2 months after initiation of drug therapy. Total blood viscosity decreased at 1 month and was further reduced at 2 months. The plasma viscosity remained unchanged during the course of the therapy (1.770 +/- 0.147, 1.776 +/- 0.162, and 1.772 +/- 0.164 centipoise at 0, 1, and 2 months, respectively; mean +/- SD, n = 14 to 17). No changes were observed in stimulus-induced actin polymerization in granulocytes, concanavalin A-induced capping in granulocytes and lymphocytes, and anti-IgG-induced caps in lymphocytes, before and after therapy. Similarly, there was no difference in the magnitude of depolymerization caused by pentoxifylline when added in vitro. Thus none of the parameters altered by pentoxifylline treatment in vitro have been observed ex vivo in patients receiving this drug. However, the decrease in total blood viscosity along with unaltered plasma viscosity suggests that the rheology of the cellular elements is being affected by the administered drug. In addition to the direct effects on the cell membrane and the cytoskeleton, pentoxifylline may exert indirect effects through its inhibitory action on cytokine production. Subtle changes in a number of parameters in leukocytes, which taken alone fail to show demonstrable changes, might ultimately be responsible for the therapeutic benefit noted with pentoxifylline.

Actins↗
PubMed1983

Effect of oral administration of highly purified eicosapentaenoic acid on platelet function, blood viscosity and red cell deformability in healthy human subjects.

Eicosapentaenoic acid (EPA), which is abundant in seafood, has been reported to be a potent antagonist of platelet aggregation and also to reduce the incidene of cardiovascular disorders. We recently reported that EPA also reduces whole blood viscosity. A highly purified EPA, in a soft capsule (75% ethylester form of EPA; EPA-E), manufactured from sardine oil was administered to 8 healthy male subjects for 4 weeks. No side effects were observed. Platelet aggregation and platelet retention significantly decreased. The EPA content in platelet phospholipids markedly increased but docosahexaenoic acid (DHA) and arachidonic acid (AA) contents did not change. A reduction in whole blood viscosity and an increase in erythrocyte deformability were also observed after 4 week's ingestion of EPA-E. The EPA content in erythrocyte membrane phospholipids markedly increased after 4 weeks, and was positively correlated with erythrocyte deformability. Reduction of platelet aggregation and improvement of the rheological properties of the erythrocyte might be explained by an increase in the EPA content in platelet and erythrocyte phospholipids.

Administration, Oral↗
PubMed1984

Beneficial effect of fish oil on blood viscosity in peripheral vascular disease.

Reports suggest that the low incidence of ischaemic heart disease in Greenlandic Eskimos is related to the effect of a diet rich in eicosapentaenoic acid on platelet reactivity and plasma lipid concentrations. A double blind randomised investigation was therefore conducted of the effects on blood viscosity of dietary supplementation with an oil rich in this fatty acid (1.8 g/day, given as fish oil) and an eicosapentaenoic acid poor oil (as corn/olive oil) in patients with peripheral arterial disease. A statistically significant reduction in whole blood viscosity was observed at seven weeks in those patients receiving the eicosapentaenoic acid rich oil. No changes in plasma viscosity, haemoglobin concentration, packed cell volume, or platelet count were seen. A significant fall in plasma triglyceride concentration was also noted only in the patients receiving oil rich in eicosapentaenoic acid; plasma concentrations of cholesterol and high density lipoprotein cholesterol were unchanged. It is concluded that rheological changes that result from a diet rich in eicosapentaenoic acid may contribute to the suggested protective effects of such a diet against arterial disease and that such changes are of potential therapeutic importance in established arterial disease.

Aged↗
PubMed1979

Amelioration of blood viscosity in sickle cell anemia by pentoxifylline. A case report.

An 18 year old female patient with homozygous sickle cell anemia (HbSS: HbS 65% and HbF 4.9%) has been suffering from painful hemolytic crises about once a week since her childhood. Under treatment with pentoxifylline (2.4 gm daily in three divided doses), the blood viscosity decreased from 6.7 to 4.9 cP (normal: 4.3 to 5.3 cP at shear rate 46/sec) and the erythrocyte filtration accelerated from 127 to 77 sec (normal: 30 to 49 sec). Though hemolysis could not be prevented by pentoxifylline, there was no further demand for analgesic medication even in the hemolytic state. By decreasing blood viscosity and improving microcirculation, pentoxifylline may prevent the vasoocclusive complications of sickle cell anemia.

Adolescent↗
PubMed1986

Blood viscosity: a pathogenetic factor in the development of essential hypertension?

Inhibition of the ouabain-sensitive Na-K-ATPase by digoxin significantly decreases erythrocyte deformability (5). Since first a decrease in this transport system has been discussed as a pathogenetic factor in the development of essential hypertension and second an increase in blood viscosity, due to an increased hematocrit has been observed in elderly hypertensives, hemorheology and sodium transport systems were examined in adolescent hypertensives and compared with age-matched normotensive controls. 73 normotensives (N; mean blood pressure 127/80 mmHg) and 53 hypertensives (H; mean blood pressure 147/94 mmHg) aged 23-27 yrs were randomly selected from an epidemiological survey, covering 1342 adolescents. While apparent whole blood viscosity at different shear rates, hematocrit, plasma fibrinogen were not significantly different, erythrocyte deformability, measured with a positive pressure filter system (pore phi 5 mu) and expressed as Q = delta P/ery.susp.Hct 10%/delta P/plasma was significantly attenuated with Q = 1.77 +/- 0.05 in H, compared to 1.64 +/- 0.04 in N (p less than 0.05) The decrease in erythrocyte deformability was not accompanied by an inhibition of the Na-K-pump nor of total K+-uptake in erythrocytes, both measured with the 86Rb uptake. There was only a slight increase in Na+-excretion in urine of 184.4 + 12.2 mval in H, compared to 162.0 +/- 10.4 mval in N (n.s.). K-/+-excretion and serum electrolytes did not show any difference. Whether the decrease in erythrocyte deformability may contribute to an increase in peripheral vascular resistance in essential hypertension has to be further clarified.

Adult↗