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

An unusual case of Bart's hydrops fetalis is reported where the patient was born to parents of Greek origin. An exchange transfusion was given. Adult haemoglobin (HbA) was present in addition to HbBart's and HbPortland. A low level of synthesis of alpha-chains was evident. The mother presented again in a subsequent pregnancy for prenatal diagnosis of thalassaemia. The fetus was diagnosed as an alpha-thalassaemia carrier, a diagnosis which was confirmed at birth. The nature of alpha-thalassaemia in the family is discussed.
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PMID:Haemoglobin Bart's hydrops fetalis syndrome in an infant of Greek origin and prenatal diagnosis of alpha-thalassaemia. 31 64

To investigate the development of diabetes mellitus in patients with thalassemia major, plasma glucose and immunoreactive insulin (IRI) levels following oral glucose and intravenous tolbutamide and glucose disappearance rates following intravenous insulin were measured in 10 patients before and during five years on a high transfusion program (HTP). Plasma immunoreactive glucagon (IRG) levels following oral glucose, intravenous insulin, and arginine were measured during the sixth year. Serial percutaneous liver biopsies were performed on seven patients. The oral glucose tolerance tests (OGAT) and mean peak IRI levels were normal in nine of 10 patients before HTP. After HTP was begun a progressive deterioration of OGTT occurred despite normal IRI levels. Following tolbutamide, the mean per cent fall in plasma glucose in the patients before HTP was significantly less than in controls (p less than 0.01) and similar to that of controls during five years of HTP in spite of higher than normal peak IRI levels. Of seven survivors after six years of HTP, three had normal OGTT and four had chemical diabetes; mean peak IRI levels were normal, but fasting IRG levels were significantly higher than in controls (p less than 0.05). In all seven patients, plasma IRG failed to increase following insulin-induced hypoglycemia and was significantly higher than in controls after arginine (p less than 0.01); after oral glucose, plasma IRG fell significantly below that of fasting only in the patients with chemical diabetes (p less than 0.03). Following intravenous insulin, the mean per cent fall in glucose before and during HTP was significantly less than in controls (p less than 0.01). Hemosiderosis and cirrhosis were present in all biopsied patients. Four patients died; two had chemical and two had nonketotic insulin-dependent diabetes. These data suggest that diabetes mellitus occurs frequently in patients with thalassemia on HTP and that insulin resistance and hyperglucagonemia, possibly due to cirrhosis, are important etiologic factors.
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PMID:Carbohydrate metabolism and pancreatic islet-cell function in thalassemia major. 32 76

The susceptibility of human red blood cells to invasion by Plasmodium falciparum was investigated in microtissue cultures with different populations of erythrocytes containing fetal haemoglobin (HbF). Preferential invasion of HbF-containing erythrocytes was observed with umbilical cord blood. The parasites showed no preference for HbF cells in blood from a subject with hereditary persistence of fetal haemoglobin (HPFH). By contrast, a significant preference for HbA-containing erythrocytes was found with blood from young infants. Further experiments demonstrated that falciparum parasites preferentially invade "young" erythrocytes. This could explain the distribution of parasites found in blood containing HbF, because HbF-containing erythrocytes are "younger" on average in cord blood, "older" in the blood of infants, and of the same average age as HbA-containing cells in HPFH. We concluded that the susceptibility of human erythrocytes to invasion by P. falciparum is not correlated with the presence of HbF, but that aging of red cells in vivo decreases their susceptibility to invasion. Semi-quantitative measurements were made of parasite growth in cells containing HbA or HbF. The growth of individual parasites in cells containing HbF was significantly retarded. This might confer a selective advantage on individuals with thalassaemia and sickle cell trait, in which HbF levels are raised in early life.
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PMID:Invasion and growth of Plasmodium falciparum in different types of human erythrocyte. 33 78

Samples of peripheral blood from patients with beta-thalassaemia major which contained significant numbers of nucleated normoblasts were stained with acridine orange and analyzed with rapid-flow cytofluorometry. The pyknotic normoblast-nuclei gave less green 'DNA' fluorescence than the (diploid) leucocytes and constituted a separate, distinct subpopulation. Mean values of the fluorescence intensities and standard deviations as displayed by multichannel analyses gave a numerical value for normoblasts with regard to their maturation stages. These mean values correlated with the differential counts of 'early and late' normoblasts in the light microscope under rigidly standardized conditions. Rapid-flow cytofluorometry thus provides an objective and quantitative way to monitor and define peripheral blood normoblast populations as a measure of the severity of 'erythropoietic stress'.
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PMID:Characterization of the normoblast population in beta-thalassaemic blood by rapid-flow cytofluorometry. 35 92

Gonadotrophin (Gn), thyrotrophin (TSH) and prolactin (PRL) reserve was evaluated in patients (aged 12-26 years old) with beta thalassaemia. Abnormalities were detected in Gn reserve only. When compared with young adult controls, three of the four female patients and one of the two adult males had markedly impaired Gn responses to LH-releasing hormone (LHRH). Of the five prepubertal males, one had no Gn rise following LHRH, while responses in the other four patients were comparable to those in boys with delayed puberty. Only one adult male had an exaggerated LH response to LHRH. TSH and PRL dynamics were normal. No correlation could be found between the severity of the disturbance in the gonadal axis and the total number of blood transfusions. Our findings correlate best with the severity of the disease process itself.
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PMID:Gonadotrophin, thyrotrophin and prolactin reserve in beta thalassaemia. 35 99

Sickle cell (SS) disease is a complex of various genetic conditions. In some, homozygosity for the beta S gene may be present alone or in combination with the heterozygous or homozygous alpha-thalassemia-2 condition. Such combinations might ameliorate the clinical and hematological condition of the patient. The same may be true for the high levels of Hb F and F-cells observed in many Hb S homozygotes. Howeever, the chemical heterogeneity of Hb F appears not to be related to the clinical status of the Hb S homozygote. Combinations of a Hb S heterozygosity with a heterozygosity for a Hb D-type of variant, for either one of two types of beta-thalassemia, two types of alpha beta- thalassemia, and five types of HPFH are discussed, and data are compared with those obtained for Hb S homozygotes. The use of advanced laboratory procedures and family studies is often necessary for an accurate diagnosis.
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PMID:Sickle cell anemia as a syndrome: a review of diagnostic features. 38 40

Molecular analysis of normal and abnormal human globin genes and their gene products has recently provided information on the precise genetic events that result in hemoglobinopathies. In the case of structurally abnormal hemoglobins, the following mechanisms can be invoked: single nucleotide base substitutions leading to amino acid replacement or chain termination variants; nucleotide deletions (or additions) leading to deletion and frameshift variants; and nonhomologous crossing over leading to the production of fused globin chains. The molecular basis of the thalassemia syndromes, disorders characterized by absent or decreased synthesis of alpha- or beta-globin chains, is quite heterogeneous. In some cases globin gene deletions have been demonstrated; whereas in others there is probably either a defect in globin gene transcription or a defect in nuclear globin messenger RNA (mRNA) processing, mRNA transport or globin mRNA stability. In one form of beta(0)-thalassemia a nonsense mutation has recently been demonstrated, and other cases are also associated with some as yet undetermined functional abnormality of beta-globin mRNA.
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PMID:Molecular genetics of human hemoglobin synthesis. 38 60

Thalassemia major is a severe and transfusion-dependent anemia that occurs in persons homozygous for a mutation that affects the capacity for synthesis of the beta-globin subunit of hemoglobin. Characterization of the molecular defects that cause beta-thalassemia is providing insight into the mechanism of globin gene regulation. Newer approaches to the management of thalassemia major include more effective chelation by use of subcutaneous desferrioxamine and attempts to obtain young erythrocytes with a longer potential for survival in recipient patients. Development of more effective chelators that may be given orally is an ongoing effort. Noninvasive evaluation of cardiac structure and function in patients with thalassemia major suggests that myocardial iron deposits begin at an early age, causing functional impairment long before the onset of clinical symptoms. Prevention or reversal of these cardiac abnormalities remains the goal of chelation therapy.
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PMID:Thalassemia major: molecular and clinical aspects. NIH Conference. 39 Nov 18

Many mutant hemoglobins and hemoglobinopathies can be identified with a high degree of specificity in the routine clinical laboratory. The most frequent abnormalities--those involving Hb S or C--are usually easily detectable in small amounts of sample analyzed by two simple methods of electrophoresis: cellulose acetate at pH 8.5 and citrate agar at pH 6. Some rarer mutants, e.g., Hb O, Hope, and Camden, can also be recognized by these two methods. Presumptive identification of other relatively frequent mutants, such as Hb D Los Angeles (Punjab) and Hb G Philadelphia, can be accomplished with additional data obtained from globin electrophoresis on cellulose acetate in acidic and alkaline buffers containing urea and 2-mercaptoethanol (or dithioerythritol). Electrophoretic profiles are presented of about a dozen hemoglobins likely to be encountered in screening programs in the U.S. Methods are also presented for identifying other genetic hemoglobin abnormalities--various types of thalassemia, Hb M, unstable hemoglobins, and those of the newborn.
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PMID:Methods for detection of hemoglobin variants and hemoglobinopathies in the routine clinical laboratory. 40 71

HB A2 was assayed by means of DE-52 microchromatography in hemolysates from 285 normal subjects and 223 beta-thalassemia heterozygotes. No overlap was found between both groups. Comparable results were observed analyzing whole blood samples collected in capillary tubes from 550 normal subjects and 295 beta-thalassemia heterozygotes. Our results demonstrate that this technique is useful in a screening program for beta-thalassemia trait.
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PMID:Quantitation of Hb a2 with DE-52 microchromatography in whole blood as screening test for beta-thalassemia heterozygotes. 40 62


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