Abnormal cation movements in human hypochromic red cells incubated in vitro

Red-cell metabolism in patients with iron deficiency

18 components of metabolism were determined in the red cells of iron-deficient patients and data were expressed per 10(12) red cells to avoid the complicating effects of hypochromia and microcytosis. Glucose consumption, AMP and ATP, glycolytic intermediates except 2,3-bisphosphoglycerate (2,3-DPG) and phosphoenolpyruvate (PEP), red-cell Na+ and the net passive leakage of Na+ and K+ at 4 degrees C were all normal. Creatine, 6-phospho-D-gluconate: NADP oxidoreductase (6PGD) activity and fresh red-cell K+ were raised, suggestive of a young cell population. However, ATP: D-fructose-6-phosphate 1-phosphotransferase (PFK) activity and ADP were low. An elevated 2,3-DPG level was attributable to the anaemia present but the somewhat raised PEP level is unexplained. It is concluded that red cells in iron deficiency show some characteristics of a young cell population; in other respects they appear normal, but in containing a low PFK activity they are abnormal.

The erythrocyte membranes in beta-thalassemia. Lower sialic acid levels in glycophorin

The sialic acids content of glycophorin of thalassemic erythrocyte membranes is about 25% lower than in glycophorin of normal erythrocyte membranes. Glycophorin extracted from old thalassemic erythrocytes separated by density centrifugation, has about half the sialic acids content found in glycophorin extracted from young thalassemic erythrocytes. Possible sialidase activty was sought in the plasma and erythrocyte membranes of thalassemic erythrocytes. No increased sialidase activity was detected in the plasma of the patients as compared to that of normal donors. Thus, other sites for sialidase activity, or other possibilities have to be explored to account for the increased sialic acid hydrolysis of glycophorin of the thalassemic erythrocytes.