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

Prenatal diagnosis of beta-thalassaemia and sickle-cell anaemia was attempted in 24 pregnancies. Adequate amounts of fetal blood (for studying globin-chain synthesis) were obtained in 22 cases. 4 cases of homozygous beta-thalassaemia and 2 of sickle-cell anaemia were diagnosed. The difference between the homozygous and non-homozygous states was well defined. Fetal bleeding from cord puncture and amnionitis resulted in the loss of three fetuses, and methods to avoid these complications are being devised. It is concluded that prenatal diagnosis of disorders of beta-globin synthesis is feasible.
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PMID:Prenatal diagnosis of beta-thalassaemia and sickle-cell anaemia. Experience with 24 cases. 6 2

Over the past three years 25 302 adults in Kentucky have been tested for haemoglobinopathies, and of these, haemoglobin A2 was measured on 3734, 1973 with microcytosis and 1761 within the normal range. The best methods of detecting beta-thalassaemia minor using red-blood-cell indices were compared. No method detected all heterozygotes. A new method was devised consisting of three parts: (1) haemoglobin electrophoresis, (2) calculation of the product of the square of the mean corpuscular volume (M.C.V.) multiplied by the mean corpuscular haemoglobin (M.C.H.) measured in units of one hundred, (3) A2 determination on all AA samples with (M.C.V.)2 X M.C.H. less than 1530 and on those with variant genotypes consistent with thalassaemia. In this series this new method detected 137 out of 138 heterozygotes with 4-4% false-positives.
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PMID:A strategy to detect beta-thalassaemia minor. 6 86

Gene duplication is one of the basic processes underlying evolutionary changes. The gamma-chains of human foetal haemoglobin is coded by multiple structural genes. The delta-chains of Hb A2 can be regarded as a duplication of the beta-locus. We have presented the first evidence for the presence of two major alpha-chain loci in man. The alpha-gene appears to have duplicated recently, since apart of the single point mutations characterizing Hb J-Buda and Hb G-Pest, the two alpha-gene products seem to be identical. Sensitive immunochemical measurement techniques may reveal structural differences which might escape detection by chemical methods based on differences in charge and/or chromatographic behaviour. Anti-alpha-chain sera recognizing the single amino acid substitution in alphaJ-Buda could be raised in rabbits. The anti-alpha-chain sera were found to be more powerful tools for detecting differences in the primary structure of the chain than the immune sera raised against the whole tetramer. None of the immune sera could reliably differentiate Hb G-Pest from Hb A1. The relative strength of complement fixation of the alpha-chains from haemoglobin A1 F and A2 was compared by hybridizing these human haemoglobins with caninehaemoglobin and measuring the quantitative complement fixation of the different hybrids with anti-Hb A1 and anti-alphaA1 rabbit immune sera. No antigenic difference among the alpha-chains from haemoglobins A1, A2 and F could be detected by this method either with anti-A1 or with anti-alphaA1 sera. These results do not exclude the possibility of conformational differences between the alpha-chains in native Hb A and Hb F. The antigenic activity of the alpha-chains of Hb A from normal subjects (alphaA1) and of the alpha-chains of Hb A from a double heterozygote for alphaJ-Buda and alphaG-Pest (alphaA1) were compared by the complement fixation technique. Definite differences could be detected in the relative strength of complement fixation by alphaA1 and alphaA1 with anti-alphaA1 serum. Final decision as to whether alpha-chain duplication is a universal phenomenon or whether it is restricted to only a part of mankind cannot be drawn until the presence of a silent alpha-thalassaemia gene is not excluded in some debated cases by reliable chemical methods. Measurement of alpha-globin genes in Hb H disease with cDNA enriched in alpha-globin sequences provided direct evidence that a non-thalassaemic subject has to have at least four alpha-globin genes per diploid cell.
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PMID:Duplication of the haemoglobin alpha-gene. 6 38

The effect of 12 and 24 h continuous subcutaneous infusion of desferrioxamine (D.F.) on urinary iron excretion was compared in 13 patients with beta-thalassaemia major and 1 with congenital sideroblastic anaemia, all of whom were receiving regular blood-transfusions. 750 mg D.F. given over a 12 h period, gave a mean total (30 h) iron excretion of 17-5 mg, which was not statistically different from the mean iron excretion of 21-5 mg when the same dose was delivered over 24 h. 1500 mg D.F. gave a mean urinary iron excretion of 28-1 mg with a 12 h infusion, which was significantly less than the mean iron excretion of 39-6 mg with 24 h infusion. The 1500 mg dose gave a significant increase in iron excretion compared with the 750 mg dose when given by either 12 h or 24 h infusion. 7 of 8 patients, given D.F. over a 12 h period, had increased iron excretion when the dose was increased from 750 to 2000 mg. When the dose was increased to 4000 mg, however, the effect on iron excretion was variable. On the other hand, ascorbic-acid therapy was invariably associated with increased iron excretion after subcutaneous D.F. In twelve studies at different dose levels of D.F., ascorbate therapy was associated with increased iron excretion ranging from 24 to 245%. It is concluded that in most patients with transfusional iron overload subcutaneous D.F over a 12 h period, at a dose ranging from 2 to 4 g daily with ascorbic-acid saturation, is at present the most satisfactory method of removing excess iron.
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PMID:Effect of dose, time, and ascorbate on iron excretion after subcutaneous desferrioxamine. 6 69

In a Greek Cypriot family in which genes for both alpha and beta thalassaemias were expressed, haematological and biosynthetic investigations indicated that one family member was homozygous for beta thalassaemia and had alpha-thalassaemia1 trait. The concurrent inheritance of an alpha-thalassaemia gene in the beta-thalassaemia homozygote seemed to have modified his degree of chain imbalance and to have reduced the clinical severity of the disease.
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PMID:Alpha-beta thalassaemia. 6 88

Three new cases of Hb 0 Arab in two families are reported from districts of Bulgaria, where a carrier state of this abnormal hemoglobin has not been established so far. One of the propositi is a double heterozygote for Hb 0 Ar/beta(0)-thalassemia. His father is a simple heterozygote for Hb 0 Ar with clear-cut cytomorphological stigmata, indicating hemoglobinosis. The second propositus, according to clinical and laboratory data is also a double heterozygote for Hb 0 Ar and beta(0)-thalassemia. The carriers investigated are of Bulgarian nationality. Their territorial origin supportsthe thesis that the gene mutation for Hb 0 Arab most probably has taken place out of the present boundaries of Bulgaria.
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PMID:Three cases of hemoglobin O Arab. 6 91

Maternal haemoglobin F production has been monitored in 11 normal pregnancies, with an immunofluorescent technique. In all cases there was a significant increase in the number of F-cells which reached a peak at 18-22 weeks' gestation. Comparison of the numbers of F-cells with the percentage haemoglobin F determined chemically indicated that the increase in maternal haemoglobin F synthesis results from an increased production of F-cells rather than from an increased synthesis of haemoglobin F by the F-cells. There was a highly significant increase in the number of F-cells in a pregnant beta-thalassaemia heterozygote.
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PMID:Pattern of maternal F-cell production during pregnancy. 7 May 89

The relative concentrations of alpha-, beta-, and gamma-globin mRNA sequences were measured in bone marrow nuclear and cytoplasmic RNA and in RNA from peripheral blood reticulocytes of three patients with homozygous beta+ thalassemia. Our results suggest that the quantitative deficiency in beta-globin mRNA may arise because of abnormal metabolism of molecules containing beta mRNA sequences. Complementary DNAs specific for each of the globins were synthesized. Variable quantities of RNA were incubated to equilibrium with 3H-labeled alpha- and 32P-labeled beta- or gamma-enriched cDNA. We found for each of the patients that the alpha/beta mRNA sequence ratio was more nearly normal in the nuclear RNA than in either cytoplasmic or reticulocyte RNA. Conversely, gamma mRNA sequences were very low in the nucleus with an increase in the relative concentration in both cytoplasm and reticulocyte RNA. The thermal stability of nucleic acid duplexes formed between beta cDNA and nuclear RNA from one patient with beta+ thalassemia was equivalent to that of duplexes formed with normal nuclear RNA. Approximately equal amounts of thalassemic alpha and beta mRNA were retained by oligo(dT)-cellulose, indicating that the 3' poly(A) segment was present on both. Our results indicate that beta-globin mRNA, although grossly normal in structure, fails to accumulate in beta+ thalassemic erythroid cells in amounts equivalent to the mRNA for alpha-globin.
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PMID:Relative stability of alpha- and beta-globin messenger RNAs in homozygous beta+ thalassemia. 7 35

Hemoglobin H disease was diagnosed prior to the twenty-second week of gestation in a pregnancy at risk for homozygous alpha-thalassemia using the technique of DNA-DNA hybridization. Fetal DNA was obtained from amniotic fluid fibroblasts obtained during the thirteenth week of gestation and grown in culture. The fetal fibroblast DNA was hybridized to radioactive alpha-globin cDNA. The number of alpha-globin genes present in the fetus was determined by comparing results of hybridization studies on the fetal DNA to similar studies on subjects with well-defined alpha-thalassemia syndromes and with normal subjects. The diagnosis of hemoglobin H disease was confirmed at birth by studies of the cord blood. This study confirms the ability of DNA-DNA hybridization techniques to distinguish the three-gene defect of hemoglobin H disease from the lethal four-gene defect of homozygous alpha-thalassemia.
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PMID:Prenatal diagnosis of hemoglobin H disease. 7 7

Urinary iron excretion after single intramuscular (i.m.) bolus injections or 12 h subcutaneous (s.c.) infusions of desferrioxamine (D.F.) was determined in sixteen homozygous beta-thalassaemia patients whose ages ranged from 10 months to 23 years. At all ages the s.c. infusions resulted in greater iron loss than identical i.m. doses. With doses of 0.5-1 g of D.F. as s.c. infusions eight out of nine children aged less than 6 years with a total transfusion iron load of less than 10 g excreted sufficient iron to achieve iron balance. These results suggest that iron loading in transfusion-dependent thalassaemics may be preventable by the use of an appropriate chelation regimen started early in life.
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PMID:Prevention of iron loading in transfusion-dependent thalassaemia. 7 45


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