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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In two pregnancies at risk for homozygous beta+ and beta0 thalassaemia, fetal blood mixed with maternal blood was obtained by placental aspiration and was purified to over 90% purity by differential agglutination with anti-i antibodies. Study of globulin-chain synthesis showed absence of beta-globulin chain in both fetuses. The diagnosis of homozygous beta-thalassaemia was made and was confirmed after the pregnancies were terminated. Thus, the defect in beta-globulin-chain synthesis in homozygous beta-thalassaemia is expressed in utero, and prenatal diagnosis is possible.
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PMID:Prenatal diagnosis of homozygous beta-thalassaemia. 7 54

Three formulae have been advocated for interpreting the blood-count when differentiating between iron deficiency and heterozygous thalassaemia: the discriminant function. M.C.V.-R.B.C.-(5 X Hb)-k, the M.C.V/R.B.C. ratio, and the (M.C.V.)2 X M.C.H. product. In a comparison of their diagnostic accuracy in microcytic adults from several countries, the discriminant function was the most satisfactory. 417 of 455 uncomplicated cases (91.6%) of iron deficiency, heterozygous alpha1- and beta- thalassaemia were correctly identified. The function was not able to distinguish heterozygous alpha2-thalassaemia from iron deficiency. A flow chart illustrates how the discriminant function can be used in haematological practice.
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PMID:Discrimination between iron-deficiency and heterozygous-thalassaemia syndromes in differential diagnosis of microcytosis. 8 63

Studies in two Jamaican Negro families, including haematological and haemoglobin analysis, haemoglobin synthesis, and globin messenger-RNA assay, have defined two alpha-thalassaemia phenotypes which resemble the severe (alpha-thalassaemia 1) and mild (alpha-thalassaemia 2) forms of the disorder described in Orientals. Genetic analysis suggests that subjects with the alpha-thalassaemia-1 phenotype are homozygous for the alpha-thalassaemia-2 determinant. Restriction-endonuclease mapping shows that alpha-thalassaemia-2 results from the deletion of one of the linked pair of alpha-chain genes. Hence the genotypes of the alpha-thalassaemia heterozygotes and homozygotes in these families are -alpha/alpha alpha and -alpha/-alpha respectively. If these are the usual alpha-thalassaemia genotypes in Negroes, these findings explain the difference in clinical expression of the disorder between Orientals and Negroes--in particular, the absence of haemoglobin Bart's hydrops and the rarity of haemoglobin-H disease in Negroes.
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PMID:Negro alpha-thalassaemia is caused by deletion of a single alpha-globin gene. 8 8

We determined the complete nucleotide sequence of the 5' noncoding region and the first 74 amino acids of the nonfunctional beta-globin mRNA in a patient with homozygous beta 0 thalassemia. We identified the molecular defect as a single nucleotide substitution in the coding region of the mRNA. At the position corresponding to amino acid 17, replacement of an adenine by a uracil changes the triplet AAG, which codes for lysine in the normal beta chain, to an amber termination codon, UAG. This type of beta 0 thalassemia represents an example of a nonsense mutation in man.
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PMID:beta 0 thalassemia, a nonsense mutation in man. 8 35

A novel approach for the ultrastructural localization of surface sialic acids is presented. Membrane-bound sialyl residues are chemically modified in situ by the covalent attachment of biotinyl residues, the latter of which are subsequently localized by ferritin-conjugated avidin. In contrast to previous methods, which have been based on electrostatic interactions, the above method does not affect cell surface charge. Consequently, the macromolecular configuration of the labeled sialoglycoconjugates is preserved. The method has been found to be more accurate in the quantitative evaluation and the topographical localization of membrane-based sialic acids both in normal and pathologically induced surface modulations. Modulations in cell surface sialic acid content and/or distribution have been demonstrated in beta-thalassemia and transformed lymphoid cells, and the consequences of such alterations are discussed regarding destruction vs. escape from the immune surveillance system.
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PMID:Ultrastructural modulations of cell surface determinants in pathological processes. 9 32

Skeletal or cardiac muscle fibers can be separated by brief (3--5 second) dissociation of formalin-fixed pieces with a Willems Polytron (Brinkmann Instrument Co.). Such separated fibers are useful for demonstration of abnormal accumulations of lipids, carbohydrates, proteins and minerals in metabolic diseases. Staining techniques for demonstration of various stored materials include: 1) toluidine blue at pH 2.8 for acid mucopolysaccharide in skeletal muscle fibers in Pompe's glycogenesis 2, 2) one-step trichrome stain for nemaline myopathy and for abnormal mitochondria in X-linked infantile cardiomyopathy, 3) periodic acid-methenamine silver stain for glycolipid-containing lysosomes in I-cell disease (mucolipidosis 2), 4) Sudan black B stain for lipid in skeletal muscle fibers in Reye's syndrome, infantile lactic acidosis, Leigh's infantile subacute necrotizing encephalopathy and Jansky-Bielschowsky late infantile ceroid lipofuscinosis, 5) iron stain for iron in cardiac and skeletal muscle fibers in thalassemia with advanced hemosiderosis, and 6) autofluorescence for "ceroid" in skeletal muscle fibers in Jansky-Bielschowsky disease.
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PMID:Histochemical methods for dissociated muscle fibers. 9 Apr 4

Iron absorption and rates of iron accumulation were analysed in a group of patients with beta-thalassaemia intermedia. Iron absorption was strikingly increased and there was a progressive iron loading with increasing age. Balance studies indicated that by the time many of these patients reach the third or fourth decades their total iron loads may be of a similar magnitude to those of transfusion-dependent beta-thalassaemia homozygotes. If these patients are to be protected from cardiac, hepatic, and endocrine complications of iron overload in middle life it will be necessary to reduce gastrontestinal iron absorption, starting from early childhood.
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PMID:Iron absorption and loading in beta-thalassaemia intermedia. 9 Sep 18

Haemoglobin F has been isolated from the red cells of individuals with the Greek form of hereditary persistence of fetal haemoglobin (HPFH), and the glycine/alanine composition of the gamma CB3 peptides determined. In contrast to previous reports we have shown that the Hb F of the Greek HPFH heterozygotes contains significant amounts of G gamma chains and circumstantial evidence indicates that these are the products of the same chromosome that carries the Greek HPFH determinant. Hence this chromosome must be directing the synthesis of G gamma, A gamma and (probably) beta and delta chains, thus implying that the Greek form of HPFH does not result from a deletion involving the globin chain structural genes. Analysis of the levels and structure of Hb F from the Greek HPFH heterozygotes and from separated cell populations from the Greek HPFH/beta thalassaemia compound heterozygotes indicate that the Greek HPFH determinant, while allowing an overall increase in gamma chain synthesis, is not the sole factor determining the absolute amount of Hb F production on a cellular basis.
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PMID:Occurrence of G gamma Hb F in Greek HPFH: analysis of heterozygotes and compound heterozygotes with beta thalassaemia. 9 88

One Arabic and two Indian patients with thalassaemia intermedia produce only Hb F for the G gamma type. Haemoglobin synthesis studies and genetic analysis indicate that they are homozygous for G gamma delta beta thalassaemia. The findings in these patients and their heterozygous relatives are compared with those in an individual homozygous for G gamma A gamma delta beta thalassaemia. From this analysis, and from previously reported data on G gamma A gamma delta beta thalassaemia, the phenotypic expression of the two varieties of delta beta thalassaemia is defined. The relationship between the clinical expression and molecular pathology of these forms of delta beta thalassaemia is discussed.
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PMID:A comparison of the homozygous states for G gamma and G gamma A gamma delta beta thalassaemia. 9 89

The synthesis of fetal hemoglobin was investigated in in vitro cultures of erythroid precursors isolated from peripheral blood of normal individuals, newborns and of subjects with different hemoglobinopathies. Synthesis of hemoglobin was assessed by 35s-methionine labeling of cultures and measurement of the radioactivity incorporated into the hemoglobins A2, A, F and S isolated by column chromatography on DE 52 cellulose. The erythroid precursors from most of the studied individuals cultured in in vitro system responded with synthesized an average of 15% of Hb F while cultures from newborns produced an average of 60% of Hb F in comparison of 73% of Hb F in peripheral blood of the same newborns. Erythroid precusors from subjects heterozygotes for beta-thalassemia, heterozygotes for HPFH, and homozygotes for Hb S produced an average of 20%, 43% and 30% of Hb F, respectively, in comparison of 7%, 14% and 9% of Hb F, respectively, present in the RBC of the same individuals. These data support the previously published results (6-11) that erythroid bursts in culture reactivate the structural genes for the gamma chain synthesis.
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PMID:[Preferential synthesis of fetal hemoglobin in in vitro cultures of erythroid precursors from peripheral blood of healthy persons and those with hemoglobinopathies]. 9 30


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