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

Whether the trimodality in the relative concentration of the hemoglobin variant Hb Leslie in heterozygotes (Huisman, Hemoglobin 1:349-382, 1977) is due to a polymorphism of the alpha-chain structural genes was investigated by conventional incubation of reticulocytes with 14C-leucine. In addition, an aliquot from each of the incubations was incubated under the same conditions but without isotope. Three Hb Leslie heterozygotes with presumably four, three (heterozygous alpha-thalassemia-2), and two (homozygous alpha-thalassemia-2) active alpha-chain genes and with 33%, 22% and 11% Hb Leslie respectively, and one patient with the Hb Leslie beta(0)-thalassemia condition with more than 85% Hb Leslie were studied. The data indicate that betaLeslie chains have a lower affinity for alpha chains that betaA chains. A concomitant alpha-chain deficiency results in a reduced incorporation of betaLeslie chains into the tetrameric Hb Leslie molecules, while the quantity of Hb Leslie produced correlates with the degree of alpha-chain deficiency. Excess of betaLeslie chains is preferentially degraded.
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PMID:Is the trimodality of Hb Leslie (alpha 2 beta 2 131 Gln---O) in heterozygotes the result of a variable number of active alpha-chain genes? Evidence for posttranslational control of hemoglobin synthesis. 74 78

The mechanism of iron chelation was studied in 16 patients with homozygous beta-thalassemia. Following the i.v. infusion of desferrioxamine, chelated iron accumulated in the plasma and its maximal level at 2 h was closely correlated with the 24-h excretion of iron in the urine. The high specific activity of chelated urinary iron indicated that the chelatable pool was much smaller than the total storage iron pool and was probably derived from nonviable red blood cells in the reticuloendothelial system. This postulate was confirmed by the direct measurement of specific activities in the spleen and liver, revealing identical values of chelated urinary iron and of iron in reticuloendothelial tissues. These findings support the concept of an easily chelatable iron pool that is derived from the catabolism of hemoglobin.
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PMID:Iron chelation in thalassemia: mechanism of desferrioxamine action. 75 May 35

The occurrence of different types of hemoglobin variants in India has been well-documented in urban populations and in certain tribal areas. Beta-thalassaemia and hemoglobins D,E,H,S, and rare variants like Hb Lepore, have been found in varying percentages. There is a higher incidence of Hb E in the Eastern region and of Hb D in certain Northern populations. The association of Hb E with beta thalassaemia G6PD deficiency has been established. The relationship with other environmental factors, like malaria, is not yet clear.
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PMID:Hemoglobin variants in India. 75 79

To determine the hemoglobin concentration at which iron absorption is minimal, five subjects with thalassemia major and one with thalassemia intermedia underwent a series of iron-absorption studies. The effect of tea as an inhibitor of non-heme iron absorption was also tested. Iron absorption increased as the hemoglobin concentration decreased, although iron absorption was much higher at any given hemoglobin level in the subject with thalassemia intermedia. In the subjects with thalassemia major, iron absorption averaged 10 per cent at hemoglobin concentrations between 9 and 10 and 2.7 per cent between 11 and 13 g per deciliter. The percentage of iron absorbed could be accurately predicted from the nucleated red-cell count (r = 0.91, P less than 0.001). Tea produced a 41 to 95 per cent inhibition of iron absorption. Since patients with thalassemia intermedia may absorb a large percentage of dietary iron, inhibitors of iron absorption, such as tea, may be useful in their management.
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PMID:Iron absorption in the thalassemia syndromes and its inhibition by tea. 75 74

Functional human globin messenger RNA was isolated from reticulocytes of two patients with homozygous beta 0-thalassemia, three patients with sickle cell beta 0-thalassemia, and one patient doubly heterozygous for beta 0-thalassemia and hemoglobin Lepore. When incubated in the Krebs type II mouse ascites tumor-cell-free system, messenger RNA from these patients actively directed the synthesis of human beta s and/or alpha- and gamma-globin chains but failed to stimulate the synthesis of any beta A-chains, even though nonthalassemic human globin mRNA preparations consistently stimulated two to four times as much beta A- or beta S-globin chain synthesis as alpha-chain synthesis when incubated in the same system under the same conditions. These results strongly suggest that functional beta A-chain-specific globin mRNA is absent in beta 0-thalassemia.
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PMID:Absence of functional messenger RNA activity for beta globin chain synthesis in beta 0-thalassemia. 80 1

A regional laboratory for the diagnosis and investigation of hemoglobinopathies was established by the Hamilton District Program in Laboratory Medicine in October 1970. Specimens from patients suspected of having a hemoglobinopathy were referred to the regional laboratory from all the hospitals participating in the program. Between October 1970 and October 1974, 3547 specimens were screened for an abnormal hemoglobin and thalassemia; 758 cases of thalassemia, 165 cases of abnormal hemoglobin and 14 mixed cases were diagnosed. Before 1970, 110 cases of thalassemia and 12 cases of abnormal hemoglobin were on record in the Hamilton region. Regionalization of laboratory services provides a more effective means of screening for abnormalities in hemoglobin structure and synthesis and facilitates the opportunity for improving diagnostic procedures.
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PMID:Hemoglobinopathies in the Hamilton region. I. A 4-year survey. 80 45

Hematological and biochemical findings in a family with hemoglobin (Hb) Beograd interacting with beta-thalassemia are presented. Hb Beograd (alpha2beta2 121 Gul leads to Val) was found in 3 members. In two members it interacted with beta-thalassemia. These two double heterozygotes had anemia of intermediate severity and splenomegaly. Studies with 51Cr and 59Fe showed a shortened life span of red cells and ineffective erythropoiesis. The abnormal Hb amounted to 86-87%, and Hb F to 5-7%. No Hb A was present. One subject of the family was heterozygous for Hb Beograd. He showed normal clinical and hematological findings. The abnormal hemoglobin was 38%. Four members of the family were heterozygotes for beta-thalassemia. The interaction between beta-thalassemia and beta-chain variants is discussed.
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PMID:Hemoglobin Beograd (alpha2beta2 121 Glu leads to Val) interacting with beta-thalassemia. 80 62

Hematologic and globin chain synthesis studies have been made in 21 children, aged 2 to 6 years, many of their parents, and several normal adults and alpha-thalassemia heterozygotes. At birth, 11 children had about 5% hemoglobin (Hb) Bart's, 5 had about 2% Hb Bart's, and 5 had no trace of Hb Bart's. A significant decrease in mean corpuscular volume. (MCV) and mean corpuscular hemoglobin (MCH) values and an increase in the beta/alpha ratio was observed in the first group; microcytosis and hypochromia were absent in the children of the second group although the beta/alpha ratio was significantly increased. The alpha chain deficiency is familial. Increased alpha/alpha ratios were present in many parents although only two parents of children with 5% Hb Bart's at birth had hematologic findings suggestive of the presence of the same type of defect as observed in the children with the larger amount of Hb Bart's at birth.
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PMID:Hemoglobin alpha chain deficiency in black children with variable quantities of hemoglobin Bart's at birth. 84 May 5

Seven patients had sickle cell trait (hemoglobin AS) and vasoproliferative retinopathy. The retinal abnormalities in these seven patients were indistinguishable from those seen in patients with clinically significant sickling hemoglobinopathies (sickle cell-hemoglobin C disease, hemoglobin S-thalassemia disease, and sickle cell anemia). All seven patients also had some evidence of associated systemic disease such as diabetes, syphilis, tuberculosis, or sarcoidosis. In the presence of an associated systemic disease, marked retinopathy can occur in the ordinarily benign condition of sickle cell trait.
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PMID:Proliferative retinopathy in sickle cell trait. Report of seven cases. 84 50

The frequency of thalassemia was determined in a group of 541 healthy adult black males. Individuals with decreased mean corpuscular hemoglobin (MCH) values were evaluated further with hemoglobin analysis, iron studies, and globin chain synthesis. Of the males screened, 13.4% had MCH levels below 27.0 pg, while 1.4% had heterozygous beta thalassemia, 2.3% had iron deficiency, and 5.7% had globin synthesis findings compatible with the diagnosis of alpha thalassemia trait (alpha thalassemia-1). This study suggests that thalassemia is one of the most frequent hematologically depictable abnormalities in American blacks.
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PMID:Frequencies of thalassemia in American blacks. 86 79


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