Erythrocyte aggregation

Selective Erythrocyte Rigidometer (Fa. Myrenne, 52159 Roetgen, Germany) 

Blood is collected from Beagle dogs, weighing 12-20 kg, or from rabbits, weighing 1.2-2.5 kg, or from Wistar rats, weighing 150-300 g. The test subjects receive the test compound by oral, subcutaneous or intravenous administration 15, 60, 90 or 180 min before the withdrawal of blood. 

Following addition of the test compound, the blood sample is incubated at 37 °C for 5 or 30 min. 

Blood is obtained from the test subjects by venipuncture and mixed with K-EDTA (1 mg/ml) or heparin (5 IU/ml heparin sodium) to prevent clotting. Erythrocyte aggregation is determined in whole blood of 40 % haematocrit. A sample of 40 xl blood is transferred to the measuring device. The red cells are dispersed at a shear rate of 600/s. After 20 s, flow is switched to stasis and the extent of erythrocyte aggregation is determined photometrically. 

The statistical significance is evaluated according to the procedure described for flow behavior of erythrocytes described above. 

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In a small study, the degree of erythrocyte aggregation during oral contraception was, at least in the short term, partly reversed by treatment with acetylsalicylic acid 100 mg/day (358). 

Dextran (O Scheme 5) solutions have been used as a plasma volume expander since 1947 owing to their non-immunogenic and well-tolerated nature as plasma substitutes [10]. Furthermore, since dextran suppresses erythrocyte aggregation and reduces blood viscosity, it has... 

The administration of berberine (104 mg/kg, i.v.) was observed to markedly and dose-dependently reduce the incidence of ventricular arrhythmia after coronary artery occlusion in rats. At a dosage of 4 mg/kg (i.v.) the alkaloid also depressed the abnormal changes in hemorrheology, such as increased platelet and erythrocyte aggregation, as well as blood viscosity. At 30 pmol/1, berberine also prevented hypoxia from shortening action potential duration and ERP in the... 

In clinical trials rutoside clearly inhibits thrombocyte and erythrocyte aggregation and inhibits the symptoms of oedema. 

EGb 761 at a dose 200 mg administered to 60 patients intravenously for 4 d improved skin perfusion and decreased blood viscosity without affecting plasma viscosity (Kleijnen and Knipschild, 1992). Another GB extract, LI 1730, increased blood flow in nailfold capillaries and decreased erythrocyte aggregation compared to placebo in 10 volunteers at a dose of 112.5 mg (Jung et al., 1990). Blood pressure, heart rate, packed cell volume, and plasma viscosity were unchanged. 

Boisseau MR, Freyberger G, Busquet M, Beylot C. Pharmacological aspects of erythrocyte aggregation. Effect of high doses of troxerutin. Clin Haemorheol 1989 9 871-876. 

Bishop J.J., Nance P.R., Popel A.S., IntaghettaM., and Johnson P.C. Effect of erythrocyte aggregation on velocity profiles in venules. Am. J. Physiol. Heart Circ. Physiol. 280 H222-H236,2001. 

In recent years there has been a growing awareness of an interrelationship between inflammation and the blood clotting processes. NAA have been shown to be effective as inhibitors of platelet and erythrocyte aggregation, as fibrinolytic agents, and as inhibitors of the release of damaging lysosomal enzymes from leucocytes. A central theme of membrane stabilization underlies many proposed explanations as to how the compounds work in these different areas. 

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