Medicina: Ematologia: Talassemie e trapianto del midollo osseo
| English |
| hemoglobin |
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| Attestation |
3
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| Part of speech |
Noun
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| Grammatical label |
Countable
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| Variant |
Hb
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| Definition |
Normal adult hemoglobin is a large complex molecule in which an iron-containing pigment (heme) is conjugated to a complex protein (globin). The globin component consists of a tetrad of 574 amino acids in the form of 2 pairs of unlike polypeptide chains designated by Greek letters. Each molecule consists of 2 alpha and 2 non-alpha chains (eg, beta, gamma, delta) that have well-recognized and consistent amino acid sequences. In the normal adult hemoglobin (HbA), which constitutes over 95% of the hemoglobin in normal persons older than 1 year, the globin component consists of 2 alpha and 2 beta chains (alpha2beta2); the remaining hemoglobin comprises HbA2 (alpha2delta2) and fetal hemoglobin (HbF or alpha2gamma2). The most important thalassemic syndrome is homozygous beta thalassemia, in which the production of beta chains is markedly decreased or absent, and a consequent decrease in synthesis of total hemoglobin occurs. This results in severe hypochromic anemia.
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| Definition source |
Lawson, JP. (2001). Thalassemia. E-Medicine. (INTEEN09)
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| Context |
Since Hb Malay is indistinguishable from HbA on routine hemoglobin electrophoresis and chromatography, it is usually identified as HbA.
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| Context source |
Fucharoen, S., et al. (2001). ‘Molecular characterization of thalassemia intermedia with homozygous Hb Malay and Hb Malay/HbE in Thai patients’. Haematologica 86(6):657-8. (RISCEN23)
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| Figure source |
http://www.wellesley.edu/Chemistry/Flick/molecules/notes.html
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| Subject field |
Haemopoiesis
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| Comprehensive concept |
Erythrocyte
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| Partitive concept |
Heme, globin, globin chain
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| Specific concept |
HbF, HbA, HbA2, Hb Gower 1, Hb Gower 2, Hb Portland
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| Related concept |
Anemia, Hb Lepore, Hb Bart´s
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| it |
Emoglobina
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| Reliability code |
3
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