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A new variant of erythrocyte glucose-6-phosphate dehydrogenase with absent activity under standard conditions of assay is described in a 23-year-old Caucasian male from Costa Rica. Indistinguishable from G6PD A(-) by electrophoretic mobility, physical and biochemical characteristics, these two variants are differentiated conclusively by NADPH inhibition(More)
To further define the conditions for forming spectrin-hemoglobin cross-linking in human erythrocyte membranes and to examine its possible effects on membrane function, we incubated normal human erythrocytes for up to 3 h in concentrations of H2O2, varying from 45 to 180 microM, in an azide phosphate buffer, pH 7.4. The chemical changes observed indicated(More)
Osmotically resistant red cells associated with some haemolytic anaemias, including hereditary xerocytosis, sickle-cell disease and beta thalassaemia minor, are more sensitive than normal red cells to exogenous in vitro hydrogen peroxide (H2O2). This sensitivity is manifested by a rapid loss of intracellular potassium, shape change, protein aggregation, and(More)
The profound and life-threatening anemia in patients with Cooley's anemia is ascribed primarily to intramedullary hemolysis (ineffective erythropoiesis), the cause of which is obscure. Based on prior morphologic data showing nuclear abnormalities, we hypothesized that accelerated apoptosis could occur in these erythroid precursors. The highly successful(More)
The life threatening anemia in beta-thalassemia major (Cooley's anemia) is characterized by profound intramedullary lysis, the cause of which is incompletely understood. Using marrow obtained from beta thalassemia major patients undergoing allogeneic bone marrow transplantation in Pesaro Italy, it became possible to directly study the mechanism of the(More)
After peroxidation, alpha and beta subunits of normal human hemoglobin demonstrated a significant differential reactivity in their ability to form methemoglobin subunits and irreducible crosslinkages with spectrin. The alpha subunits formed crosslinks with spectrin in the absence of exogenous hydrogen peroxide, whereas both the beta subunit and the intact(More)
Hemoglobin Constant Spring (HbCS) is the most common nondeletional alpha-thalassemic mutation and is an important cause of HbH-like disease in Southeast Asia. HbCS variants have an almost normal mean cell volume (MCV) and the anemia is more severe when compared with other alpha-thalassemic variants. We explored the pathobiology of HbCS red blood cells(More)
Hereditary spherocytosis (HS) is a common hemolytic anemia of variable clinical expression. Pathogenesis of HS has been associated with defects of several red cell membrane proteins including erythroid band 3. We have studied erythrocyte membrane proteins in 166 families with autosomal dominant HS. We have detected relative deficiency of band 3 in 38(More)