Ramakrishnan Swaminathan

The hemorheological parameters, plasma viscosity, hematocrit, erythrocyte aggregation and deformability of blood samples obtained from plasmacytoma patients are measured by capillary viscometer, microcentrifuge, Myrenne aggregometer, and filtrometer, respectively. These parameters are significantly altered in patients compared to those of normal subjects. The plasma viscosity and erythrocyte aggregation are increased, whereas erythrocyte deformability and hematocrit are decreased. Based on these parameters the hemorheological risk factor profiles are developed and by their overall risk factors, the patients with low and high risk factors are identified.

Normal erythrocytes (discocytes) obtained from the blood samples of healthy volunteers are subjected to shape transformation into stomatocytes and echinocytes by treatment with various concentrations of Triton × 100 and sodium salicylate, respectively. Aggregation index of these samples is measured by Myrenne aggregometer. As deformability of these cells contributes to their aggregation process, this parameter is also measured by Myrenne filtrometer. The results show that the morphological changes in these cells are dose-dependent which affect the aggregation and deformability of these cells. The deformability of echinocytes does not show significant increase with increasing concentration, whereas, a significant decrease for stomatocytes is observed. Despite the varying pattern of deformability, the aggregation of these shape-altered cells is reduced.

Aggregation of erythrocytes at Hct 5% in suspension of varied concentration of dextran 40 and dextran 70, placed in a glass chamber, is analysed under dynamic conditions by transmission of He-Ne laser light. The transmitted intensity data are collected, digitised and processed by a dedicated software. The results show that dextran 40 favours disaggregation of erythrocytes whereas dextran 70 increases the growth of aggregates. Also, the applied inhomogeneous magnetic field alters the rate of aggregation process considerably. The various parameters are analysed for the entire data. A comparison of these parameters in blood samples obtained in the presence and absence of the applied magnetic field are discussed.

The sequential analysis of the aggregation process of erythrocytes subjected to biochemical changes by inducing acidity in suspending medium are investigated in vitro. Erythrocytes obtained from blood samples of healthy adult volunteers, suspended in native and pH lowered plasma are allowed to interact freely to form aggregates under gravitational force and are then analysed by an On-line He-Ne laser light aggregometer. The aggregation index is estimated from the changes in transmitted laser light intensity corresponding to the interaction of erythrocytes. These signals are continuously detected and digitised. Similar studies are also carried out with erythrocytes suspended in dextran both at normal and low pH. The result demonstrates that the aggregation index of erythrocyte sample at lower pH in plasma and dextran solution is reduced when compared to that at normal controls. As alteration of aggregation process by this mechanism may play an important role in flow dynamics of blood in microcirculation, these studies are clinically highly relevent.