Protective effect of capsaicin on the osmotic fragility of human erythrocytes.

Capsaicin exerts a stabilizing effect on erythrocytes making them more resistant to lysis under hypotonic stress. The protective action of capsaicin on osmotic fragility (OF) was not receptor mediated since no dose responsive effect was observed. The results suggest that this protective effect of capsaicin on OF is due to a direct interaction of capsaicin with the erythrocyte membrane rather than due to any alteration in the intracellular metabolism of erythrocytes.

Insulin-mimetic effect of (-) epicatechin on osmotic fragility of human erythrocytes.

(-) Epicatechin, a benzopyran extracted from the bark of Pterocarpus marsupium, is reported to have insulin like activity. The present work is undertaken to study the effect of insulin on erythrocyte osmotic fragility (OF) and then to evaluate the insulin-like role of (-) epicatechin on human erythrocytes. Insulin exerts a protective effect on erythrocyte OF and shows a dose response which is similar to other typical insulin effects i.e. a maximum at 0.1 nM and a lower effect at higher and lower concentration. (-) Epicatechin (1 mM) also shows protective effect, similar to insulin, on the OF. Ouabain (1 mM) has completely abolished the insulin effect on OF, and failed to have any effect on the action of (-) epicatechin, showing that (-) epicatechin and insulin act by a different mechanism of action while eliciting their protective effects on red cell OF.

Insulin modulation of Na/H antiport in rat red blood cells.

Red blood cells have been shown to possess specific insulin receptors, with characteristics similar to the receptors of typical target cells. The present work was carried out to study the modulation of amiloride sensitive Na/H antiport by insulin on rat red blood cells. The activity of the Na/H antiport was determined by a new technique which involves the measurement of the fluorescence of 2',7'-bis(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF) loaded rbc's as function of their intracellular pH (pHi). Our results show that the antiport in red blood cells displays the same behaviour as in other cells and it is inhibited by amiloride. Insulin stimulates the antiport with a dose-dependence similar to other typical insulin effects: a maximum at 10 nM and a smaller effect at higher and lower hormone concentrations. Insulin effect on the antiport was completely abolished by amiloride (0.1 mM) and significantly inhibited by ouabain (1 mM) showing, also in red blood cells, the strict dependence of the Na/H antiport on the functioning of the Na pump.

Regulation of red cell acetylcholinesterase activity in diabetes mellitus.

Despite the fact that the significance of red cell membrane acetylcholinesterase (AChE) is unknown, this enzyme of red cell assumes importance since many of its properties have been found to be similar to purified enzyme form of brain tissues. Our investigations on the effect of insulin-dependent diabetes mellitus on red cell AChE revealed that the activity of this enzyme is significantly decreased in diabetes. Insulin treatment restored the activity to the normal level. Solubilization of normal, diabetic and insulin treated diabetic red cell membranes with Triton X-100 (0.2% v/v) caused a general decline in AChE activity, however the per cent decline in activity of diabetic enzyme was lower as compared to normal and insulin treated conditions. From our results it is inferred that the decreased red cell AChE activity in diabetes is due to lesser number of active enzyme molecules and also due to altered membrane microenvironment.

Red cell phosphoglycerate kinase in insulin-dependent diabetes mellitus.

Red cell phosphoglycerate kinase (PGK) activity was determined in normal individuals and patients with, type I (insulin-dependent) diabetes and insulin treated diabetes. The PGK activity was significantly (P less than 0.001) elevated in diabetes, however it is restored to normalcy after insulin treatment (normal 282.54 +/- 9.46, type I diabetic 342.06 +/- 6.24, insulin treated diabetic 292.66 +/- 7.12 IU/g haemoglobin at 37 degrees C). No significant alteration was observed in the percentage of PGK bound to the membrane fraction of red cells in all the three conditions. The results indicate that the increased PGK activity is a result of a regulatory mechanism induced by the fluctuation of ATP level in response to elevated Na:K pump rate of erythrocytes in type I diabetes mellitus.

Effect of respiration of mean frontal P. QRS and T axis in normal young adults.

Deep inspiration shifted the mean frontal plane axis of P, QRS and T waves to the right in all the cases. Greater degree of shift in AP and AQRS was observed in cases where the resting axis had been 0 degrees to +30 degrees and minimum shift was observed where the resting axis was between +61 degrees to +90 degrees. Axis of the T wave though shifted to the right with deep inspiration in all the cases but there had been no statistically significant difference in the degree of shift in the three groups. In none of the case, axis changed from normal to abnormal degree.