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Title: | Methemoglobinemia and ascorbate deficiency in hemoglobin E β thalassemia: metabolic and clinical implications. |
Authors: | Allen, A. Fisher, C. Premawardhena, A. Bandara, D. Perera, A. Allen, S. St Pierre, T. Olivieri, N. Weatherall, D. |
Keywords: | Beta thalassemia |
Issue Date: | 2012 |
Publisher: | American Society of Hematology. |
Citation: | Blood.2012 ;120(15):2939-44 |
Abstract: | ABSTRACT: During investigations of the phenotypic diversity of hemoglobin (Hb) E β thalassemia, a patient was encountered with persistently high levels of methemoglobin associated with a left-shift in the oxygen dissociation curve, profound ascorbate deficiency, and clinical features of scurvy; these abnormalities were corrected by treatment with vitamin C. Studies of erythropoietin production before and after treatment suggested that, as in an ascorbate-deficient murine model, the human hypoxia induction factor pathway is not totally dependent on ascorbate levels. A follow-up study of 45 patients with HbE β thalassemia showed that methemoglobin levels were significantly increased and that there was also a significant reduction in plasma ascorbate levels. Haptoglobin levels were significantly reduced, and the high frequency of the 2.2 haptoglobin genotype may place an additional pressure on ascorbate as a free-radical scavenger in this population. There was, in addition, a highly significant correlation between methemoglobin levels, splenectomy, and factors that modify the degree of globin-chain imbalance. Because methemoglobin levels are modified by several mechanisms and may play a role in both adaptation to anemia and vascular damage, there is a strong case for its further study in other forms of thalassemia and sickle-cell anemia, particularly when splenic function is defective. |
Description: | Indexed in MEDLINE |
URI: | http://repository.kln.ac.lk/handle/123456789/20486 |
ISSN: | 0006-4971 (Print) 1528-0020 (Electronic) 0006-4971 (Linking) |
Appears in Collections: | Journal/Magazine Articles |
Files in This Item:
File | Description | Size | Format | |
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hemoglobin E beta thalassemia.pdf | 111.74 kB | Adobe PDF | View/Open |
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