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Effect of ethanol on blood viscosity and erythrocyte flexibility in healthy men.

The effects of ethanol on blood rheology were studied in twelve healthy male volunteers each serving as his own control. They drank 1.5 g (33 mmol) of ethanol per kg body weight in fruit juice over 2.5 h under controlled laboratory conditions. Blood and plasma viscosity, packed cell volume and erythrocyte flexibility were measured before and 3, 12 and 16 h after ethanol ingestion began, and again during a second session equal volumes of fruit juice were consumed. Packed cell volume varied similarly after ingestion of juice with or without ethanol. Blood viscosity remained almost unchanged after ethanol, while drinking of juice caused an initial decrease followed by a significant (P less than 0.05) increase from 4.04 (SEM 0.06) to 4.32 (SEM 0.18) mPa.s. The juice also caused more significant fluctuations in erythrocyte rigidity (whole blood) than ethanol, which had parallel but insignificant effects. We conclude that a blood ethanol concentration of 28 mmol l-1 failed to induce any marked changes in blood rheology.

Adult↗

Whole blood viscosity in polycythaemia: the effect of iron deficiency at a range of haemoglobin and packed cell volumes.

The effect of iron deficient red cells changes (MCH range 20.0-32.6 pg) on whole blood viscosity (WBV) at high and low shear rates (94.5 and 0.51 s-1), has been assessed at a wide range of standardized PCV (0.30-0.65) and standardized Hb values (10.0-22.0 g/dl). Particular attention was given to the precision of PCV measurement. At all PCV values there was no correlation between MCH and WBV, whereas at all Hb values there was a significant negative correlation between MCH and WBV. If the treatment of polycythaemia is by venesection, iron deficient red cell changes occur frequently. These changes are unimportant if control of the WBV is the objective of treatment, as long as the PCV is accurately measured. Alternatively, in the secondary polycythaemias, where oxygen saturation is reduced, the induction of iron deficient red cell changes could be regarded as disadvantageous since at a standard PCV of 0.50 the Hb and hence oxygen carrying capacity is reduced by approximately 11% between MCH values of 30 and 20 pg.

Blood Viscosity↗

[Blood viscosity in diabetes mellitus (evaluation on the basis of high shear rates)].

In 45 diabetic patients (22 men and 23 women) subdivided in relation to type and vascular complications we have evaluated the blood viscosity at high and low shear rates. From the obtained results it is evident that only at low shear rates this hemorheological parameter distinguishes diabetic patients from normal subjects and diabetic patients without vascular complications from those with these complications. This result is present only because these shear rates are dependent on the influence of the erythrocyte aggregation which is altered in the diabetic disease.

Blood Viscosity↗

Morning increase of whole blood viscosity in obstructive sleep apnea syndrome.

OBJECTIVE: Patients affected by obstructive sleep apnea syndrome (OSAS) have an increased risk of cardiovascular diseases such as stroke and myocardial infarction. The pathophysiological mechanisms leading to increased vascular risk are still matter of debate. A relative morning hyperviscosity could be one of the leading mechanisms of cardiovascular morbidity which is actually known to be especially high in the morning hours. METHODS: Whole blood viscosity (WBV) at seven shear rates, ranging from 0.47 to 118 sec(-1), haematocrit (Hct), and plasma fibrinogen (F) concentration, were measured on venous blood samples in 12 patients with OSAS and in 8 healthy controls at 8-9 p.m. and at 7-8 a.m. the morning after. WBV values were normalized on Hct by the computation of the standardised normal deviate z on the normal database of the laboratory. RESULTS: No changes were observed in controls. Hct, F and normalized WBV (independently from Hct changes) significantly increased in the morning hours in OSAS patients. CONCLUSIONS: Viscosity of whole blood increases in the morning in OSAS patients but not in healthy controls. This condition may be related to the increased susceptibility to cerebral ischemia in patients affected by OSAS, particularly evident in the early morning.

Adult↗

[The clinical significance of blood viscosity in degenerative angiopathies].

During an examination of a group of 63 patients with chronic ischaemic heart disease and condition after myocardial infarction the viscosities measured with the help of a rotation viscosimeter lay clearly above the values of good reference persons. There were positive correlations of the blood viscosity to the haematocrit value, fibrinogen level, globulin content as well as to the total protein, total lipid and cholesterol level. In the transition to the logarithm of the viscosity the measure for the linear dependence with the exception of the total protein level became smaller. A formation of partial correlation coefficients by means of the exclusion of the haematocrit in every case resulted in increasing coefficients r for the investigated parameters of the lipid metabolism cholesterol, total lipids and triglycerides.

Blood Proteins↗

Erythrocyte Na+-Li+ countertransport and blood viscosity in arterial hypertension.

The aim of this study was to evaluate together the main hemorheologic parameters and one of the transmembrane ion transport systems in erythrocytes of subjects with normal and elevated blood pressure. Three sex-, age-, and weight-matched groups consisting of 15 normotensive subjects (NT) with no parental hypertension, 15 patients with essential hypertension (EH) at stage 1-II WHO, and eight patients with secondary hypertension (Sec.H), respectively, were studied. Red blood cell Na+-Li+ countertransport (CTT), blood viscosity (eta B) at shear rates of 230 X S-1, 115 X S-1, and 46 S-1 and plasma viscosity (eta P) at shear rate of 46 X S-1 were measured. Plasma proteins and fibrinogen were also evaluated. CTT was higher in EH than in NT (P less than 0.01), while no significant difference was found between NT and Sec. H patients. eta B at 115 X S-1 and 46 X S-1 was higher in EH, but not in Sec. H, than in NT patients (P less than 0.05). No difference in eta P, plasma proteins and fibrinogen levels was observed between EH and NT. Elevated eta B and/or CTT may indicate a structural alteration in the erythrocyte membrane of some essential hypertensive patients. This is consistent with the hypothesis that a widespread membrane disorder is involved in the pathogenesis of primary hypertension.

Adolescent↗

Whole blood viscosity, plasma viscosity and erythrocyte aggregation in nine mammalian species: reference values and comparison of data.

In this study species-specific values for whole blood viscosity (WBV), plasma viscosity (PV) and erythrocyte aggregation (EA) were determined in a total of 360 animals. We used 40 individual adult animals of nine mammalian species: horse, pig, dog, cat, rat, cattle, sheep, rabbit and mouse. WBV measurements were carried out using a LS30 viscometer, PV was measured using OCR-D and EA was measured using a Myrenne aggregometer and the LS30 (aggregation index at low shear rate). At low shear rates (0.7 s(-1) and 2.4 s(-1)) haematocrit (Hct)-standardized (40 % Hct) samples showed a higher value of WBV and EA in horse, pig, dog and cat. In cattle, sheep, rabbit and mouse, EA and WBV were markedly decreased and EA was almost undetectable, although the plasma fibrinogen concentration was higher in these animals. Rats showed the highest WBV at low shear rate in native blood and WBV was not different from horse in Hct-standardized blood; however, EA was very low in the rat, a result that might be explained by mechanical or geometrical properties of the red blood cell. EA correlated with the plasma protein concentration in each species except dog and mouse. In horse, cattle and pig, EA correlated with the plasma fibrinogen concentration. At high shear rate (94 s(-1)), WBV was higher in cattle than cat and rat, and dog had higher values than horse, suggesting specific interspecies differences depending on low shear and high shear values of WBV, as a result of mechanisms that influence RBC flexibility. PV was highest in cattle and lowest in rabbit and mouse and did not correlate with WBV. Haemorheological parameters differed between the species. Each species has its own rheological fingerprint. The physiological significance of these variations among mammalian species has not yet been established. Viscosity contributes to endothelial cell shear stress. While haemorheological parameters differ across the species it may be postulated that factors influencing flow-mediated endothelial cell signal transduction are different among the species.

Animals↗

Effects of oral and intravenous defibrotide on blood viscosity in patients with peripheral obliterative arterial disease.

Patients with peripheral obliterative arterial disease received 400 mg of defibrotide intravenously (seven patients) or orally (nine patients). Blood and plasma viscosity were measured before therapy, at 30 minutes after and one hour after intravenous administration, and at 1, 2, 3, and 8 hours after oral administration. Thirty minutes after intravenous administration, blood viscosity at a shear rate of 30 sec-1 was reduced from 9.99 to 9.00 and at a shear rate of 180 sec-1 from 6.61 to 6.33 (P less than 0.05). Viscosity returned to baseline after 60 minutes. At 1, 2, and 3 hours after oral administration, blood viscosity at a shear rate of 30 sec-1 was reduced from 8.53 to 7.44, 6.88, and 7.19 (each P less than 0.01) and at a shear rate of 180 sec-1 from 5.88 to 5.51 (P less than 0.05), 5.14 (P less than 0.05), and 5.38 (P less than 0.01); the levels at eight hours were not significantly different from baseline values. Plasma viscosity was not affected by defibrotide. These data confirm previous evidence of a rheologic effect of defibrotide in patients with peripheral obliterative arterial disease and indicate that such an effect can be achieved with oral administration.

Administration, Oral↗

Changes in haematological indices, blood viscosity and inhibitors of coagulation during treatment of endometriosis with danazol.

The effects of treatment with danazol (600 mg daily) on haemostatic and haematological function were investigated in 18 pre-menopausal women with endometriosis. Blood samples were taken at 2 pre-treatment visits, at 6, 12 and 24 weeks on treatment, and at 6 weeks after discontinuation of the drug. Haemoglobin, red cell count, haematocrit and platelet count all rose significantly during treatment with danazol (p < 0.01 vs. baseline). Plasma fibrinogen levels fell significantly (p < 0.01), while whole blood viscosity increased during treatment and remained significantly elevated at follow-up. The prothrombin time shortened, but remained within normal limits, and there were no significant changes in factor VII:C, VIIa, or fibrinopeptide A. No significant changes were found in platelet function. Plasma B-beta 15-42 increased significantly. Functional levels of protein C, protein S, and antithrombin III, all rose significantly, above the normal range, while C4b-binding protein levels fell. We conclude that the observed changes in coagulation inhibitors and fibrinolytic activity may be considered beneficial in the context of venous thromboembolism. The rheological effects, however, indicate a degree of caution in the use of the drug in individuals considered to be at risk from arterial cardiovascular disease.

Adult↗

[Effects of tetramethylpyrazine and ferulic acid alone or combined on vascular smooth muscle, blood viscosity and toxicity].

The experiments showed that both tetramethylpyrazine and ferulic acid relaxed the norepinephrine-induced spasmodic contraction of rabbit and rat aorta strips, increased the coronary flow of isolated guinea pig hearts and reduced the whole blood viscosity in rats. Evaluated with Burgi's equation, the combined effect of these 2 drugs was obviously potentiated, but the combined acute toxicity in mice was greatly reduced.

Animals↗

Effects of long-term treatment with suloctidil on blood viscosity, erythrocyte deformability and total fibrinogen plasma levels in diabetic patients.

1-(4-Isopropylthiophenyl)-2-n-octylaminopropanol (suloctidil, Sulocton), a drug introduced into clinical practice for the treatment of cerebral and peripheral vascular insufficiency and its complications, has been shown to decrease blood hyperviscosity after long-term treatment in diabetic patients. Suloctidil was particularly effective in lowering measured blood viscosity at high shear rate (230 s-1). At low shear rate (0.77 s-1) a decreasing effect was also observed but reached a statistically significant level only after one month. Since neither total plasma fibrinogen levels nor red blood cell deformability were modified by suloctidil treatment, its lowering effect on blood hyperviscosity could be due to a hitherto unrecognized mechansim of action.

Adult↗

[Blood viscosity and red cell deformability in primary hyperlipoproteinemia (author's transl)].

In patients with primary hyperlipoproteinemia (types IIa, IV, IIb) we determined by means of a Wells-Brookfield plateconeviscometer and an Ubbelohde capillary-viscometer the serum-, plasma-, apparent and relative apparent blood viscosity as well as the red cell deformability with a filtration technique. All parameters were found to be significantly changed in comparison to those of a normolipidemic control-group: The viscosity values of type IIb showed the greatest increase and of type IIa the smallest, while the red cell deformability was reduced in all types to the same degree.

Blood Viscosity↗

Hypertension, blood viscosity, and cardiovascular morbidity in renal failure: implications of erythropoietin therapy.

Recombinant human erythropoietin is a major advance in the management of patients with chronic renal failure. The sustained dose-dependent rise in haematocrit which it produces effectively abolishes symptoms of anaemia, but at the cost of an increase in blood viscosity. This in turn predisposes to increased vascular resistance and the development of hypertension. Over half of all deaths of patients with end-stage renal failure are from cardiovascular disease, notably myocardial infarction, heart failure, and stroke, for which hypertension is a known risk factor. Erythropoietin-related increases in blood pressure are therefore of particular concern, and seem to be most severe in previously hypertensive patients. There is now a need to establish the optimum rate and extent of rise of haematocrit required to alleviate symptoms without incurring undue risk.

Blood Viscosity↗

Increased whole blood viscosity combined with decreased erythrocyte fluidity in untreated patients with essential hypertension.

Erythrocyte fluidity and other haemorheological variables were studied in 22 patients with essential hypertension and compared with age- and sex-matched healthy controls. Hypertensive patients displayed a significantly lower erythrocyte fluidity (P less than 0.001). Similarly, significantly elevated values for haematocrit, plasma and whole blood viscosity, as well as aggregation tendency were observed compared to controls. Although differing in these respects from controls, there were no obvious relationships between these rheological variables and either systolic or diastolic blood pressure. The significantly lower erythrocyte fluidity and other changes in haemorheological variables of red blood cells found in hypertensive patients may be explained by an enlarged metabolic pool of free calcium ions in these red blood cells. It is suggested that the molecular mechanisms underlying the evolution of essential hypertension are multifactorial rather than being based on a single molecular derangement. Primary events resulting in altered physicochemical properties of the red blood cells may work in concert in the development of essential hypertension, in addition to the increased availability of calcium ions and their potential role in smooth muscle contraction.

Adult↗

[Influence of metabolic control on blood viscosity and platelet activity in insulin requiring diabetics].

Blood and plasma viscosities were determined using respectively a Couette type micro-viscometer (LS 30) and an automatic capillary viscometer (FICA). Plasma beta-thromboglobulin (beta-TG) levels were determined by radioimmunoassay. These parameters were measured in a group of 11 poorly controlled insulin requiring diabetics before and after blood glucose normalization using an artificial pancreas (Biostator GCIIS). Before connection to the artificial pancreas, blood and plasma viscosity and beta-TG levels were significantly higher in diabetics than in controls. The strict metabolic control obtained by the artificial pancreas resulted in a normalization of the hemorheological parameters and in a significant reduction of plasma beta-TG levels after 48 h. These results suggest that the metabolic control of diabetes influences the rheological behavior of blood and the metabolism of platelets.

Adolescent↗

[Improvement of blood viscosity in sickle-cell anaemia by pentoxifylline (author's transl)].

An 18-yer-old girl with homozygotic sickle-cell anaemia (HbSS: HbS 65% and HbF 4.9%) suffered from painful haemolytic crises since six years of age, these crises occurring almost weekly of late. Pentoxifylline (2.4 g daily in three divided doses) decreased blood viscosity in vitro from 6.7 to 4.9 (normal 4.3-5.3 at 46 s-1 shear rate) and erythrocyte filtration accelerated from 127 to 77 s (normally 30-49 s). Although pentoxifylline could not prevent haemolysis, previously necessary analgesics were no longer required, even during haemolytic crises. Thus the drug lowers viscosity also in vivo and thus improves microcirculation. It has a prophylactic effect against vaso-occlusive complications of sickle-cell anaemia.

Adolescent↗

Variations in blood viscosity in patients with acute cardiogenic pulmonary oedema treated with frusemide.

In 10 patients with acute cardiogenic pulmonary oedema, treatment with large doses of intravenous frusemide (mean dose 156 mg) induced no signs of haemoconcentration. On the contrary, during an observation period of 2 h after start of treatment we registered a significant reduction of mean blood viscosity and mean haematocrit, indicating haemodilution. All the patients also received a basic treatment of intravenous pethidine and nasal oxygen and the conclusion is therefore that large doses of intravenous frusemide in treatment of acute cardiogenic pulmonary oedema can be given without risk of haemoconcentration when combined with intravenous pethidine and nasal oxygen.

Acute Disease↗