Hemoglobin synthesis in a 34-year-old man of Laotian ancestry with Hb E/β°- thalassemia was studied. Hemoglobin electrophoresis exhibited only Hb F and Hb E. Reticulocytes and bone marrow cells showed no Hb A synthesis. The proportion of Hb F increased (from 14 to 50%) with the density of RBCs fractionated on a discontinuous gradient of Stractan. Reticulocytes were also heterogeneous with regard to their density and their Hb F synthesis: the proportion of Hb F synthesis increased with their density. Fractionation of bone marrow cells by density on a discontinuous gradient of Stractan provided populations of cells at different stages of maturation, the more mature having the greater density. Study of hemoglobin synthesis in bone marrow cells indicated that the proportion of γ-chains synthesized increased and the pool of free α-chains decreased with erythroblast maturation; in contrast, the proportion of β E-chains compared to α-chain synthesis remained constantly low. These results provide evidence that the increased amount of Hb F found in the blood of the patient was mostly due to the positive selection, in bone marrow and in peripheral blood, of cells containing Hb F. In contrast, colonies of early erythroid precursors derived from the blood of the patient exhibited an enormous reactivation of Hb F synthesis in culture. The low proportion of β E-chain synthesis (about 30% of α-chain synthesis) remained unchanged during the erythroid maturation of most immature erythroblasts to reticulocytes. The combination of two thalassemic alleles, one totally deficient (β°) the other partially deficient (βE), can explain the clinical severity of the association β⁰-thalassemia/Hb E.

Keywords:
β-Thalassemia, Erythroid cell culture, Globin chain synthesis, Hb E
This content is only available via PDF.
© 1980 S. Karger AG, Basel
1980
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.