Erythrocyte rheological changes in obese patients: influence of hyperinsulinism.

Objective: To investigate the rheological properties of RBC in obese subjects and the factors associated with their changes.

Subjects: Two consecutive studies of non diabetic obese subjects.

Measurements: Filtration index of RBC using the Hanss hemorheometer, RBC filterability using a cell transit time analyser and RBC aggregation measured on the Myrenne aggregometer.

Angiography contrast agents interact with serine proteinases. The molecular structure of the model system elastase/iohexol.

Pancreatic elastase was co-crystallised with iohexol, a tri-iodo benzenic contrast agent used in angiography analyses. The X-ray analysis of the complex reveals the presence of three molecules of iohexol associated with the proteinase with low occupancy factors. Two iohexol molecules are located in and near the active site of the enzyme and provide a model for explaining the inhibition of the hemostatic system, one of the major and inconvenient side effect associated with these chemicals.

Glucagon and noradrenaline reduce erythrocyte deformability.

An impairment in red blood cell (RBC) deformability has been reported in several diseases and might be involved in the pathogenesis of atherosclerosis. The aim of the present study was to test in vitro the effect of two "stress hormones," norepinephrine and glucagon, on the filterability of RBCs from healthy subjects. Measurements were performed with the Hanss hemorrheometer, and results were expressed as the rigidity index (RI).

Erythrocyte deformability in diabetes and erythrocyte membrane lipid composition.

Erythrocyte deformability was assessed in 40 diabetic patients, 24 insulin-dependent (IDD) and 16 non-insulin-dependent (NIDD), by measuring the initial filtration flow rate of whole blood, isolated red blood cells (RBC), and isolated RBC membranes with the Hanss hemorheometer, and its relationship to the plasma and ghost membrane lipid composition was investigated. RBC deformability was significantly reduced, whereas the deformability of the isolated RBC membranes did not differ significantly from the controls. In the plasma, the triglycerides were high, the high-density lipoprotein (HDL) cholesterol was reduced, and the ratio of total cholesterol over HDL cholesterol was high as compared with the controls.

[Rapid procedure for the preparation of erythrocytes destined for deformability measurements].

A rapid procedure for red blood cell isolation by centrifugation is proposed, in which 96% of leucocytes are removed. The middle age of the erythrocytes is verified. This procedure applied to erythrocyte rheological studies (by the initial filtration flow rate) confirms the decreased deformability of senescent red blood cells.