Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma vitamin E levels were found to be decreased (less than 0.5 mg) in thalassemia and in 17 out of 20 patients with Gaucher's disease, where the levels were two standard deviations below the normal mean value. In the latter, the decrease in vitamin E levels correlated with the severity of the clinical expression of the disease and correlated inversely with the degree of hepatosplenomegaly and serum tartrate-resistant acid phosphatase activity. In both diseases, there was no evidence for intestinal malabsorption of the lipid-soluble vitamin. In spite of the different etiology, pathophysiology, and clinical expression, severe vitamin E deficiency could result in both diseases by a common mechanism. In thalassemia, rapid consumption of vitamin E occurs while neutralizing oxidative damage in the pathological erythrocyte membranes and in other tissues. In Gaucher's disease, lysosomal accumulation of glucocerebroside may stimulate phagocytes into a maintained "respiratory burst" with excessive production of oxygen free radicals, resulting in increased utilization and eventual deficiency of vitamin E. Efficacy of antioxidant therapy was evaluated by administration of vitamin E with and without canthaxanthin, which has similar antioxidant properties to beta-carotene, to patients with beta-thalassemia. The results showed increased serum vitamin E levels and a decrease in the extent of erythrocyte lipid membrane peroxidation, while no significant changes occurred in hemoglobin levels and in transfusion requirements.
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PMID:Vitamin E deficiency due to increased consumption in beta-thalassemia and in Gaucher's disease. 675 58

Hemoglobin (Hb) North Shore (beta 134 val leads to glu) is a mutant hemoglobin that is associated with the phenotype of mild heterozygous beta-thalassemia. Heterozygotes are characterized low normal hemoglobin levels or mild anemia, microcytosis, increased HbA2, and 34%-38% Hb North Shore. The mechanism of the anemia and microcytosis associated with Hb North Shore was explored by studies of hemolysate thermal instability, peripheral blood globin biosynthesis, and whole blood oxygen affinity. Hb North Shore was mildly heat unstable in comparison to normal adult hemolysate. Pulse labeling of reticulocytes with 3H-leucine showed an alpha/beta ratio of 1.35 (normal 1.0). The beta North Shore/alpha ratio was 0.22-0.27, which was less than expected on the basis of gene dosage and less than that seen for most beta-chain variants. The beta A/alpha ratio was 0.50, as would be expected. The beta North Shore/alpha ratio was 0.26 after a 15-min pulse and did not decrease during 120 min of chase. These findings suggest that suboptimal synthesis rather than posttranslational degradation is responsible for the thalassemic phenotype associated with this variant hemoglobin. These observations parallel the findings in heterozygous HbE. It is not presently known whether the thalassemia phenotype is conferred by the structural mutation itself or by another mutation cis to the beta North Shore gene.
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PMID:Hemoglobin North Shore: a variant hemoglobin associated with the phenotype of beta-thalassemia. 682 4

The hemoglobin of 70 diabetics with retinopathy was analysed. 56 patients had pathologically elevated values, 12 values were within the upper normal limit and in 2 cases the findings were normal. This hemoglobin variant is characterized by an increased affinity of oxygen. Clinically and pathologically speaking the elevated HbA1c value could be a causal factor in diabetic retinopathy. Comparisons with sickle cell anemia and thalassemia seem to indicate that hemoglobinopathy and retinopathy are pathogenetically related.
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PMID:[Significance of elevated hemoglobulin A1c for the pathogenesis of diabetic retinopathy]. 686 53

Hb Evanston (alpha 14 Trp leads to Arg) was detected on cellulose acetate at pH 8.4 as a band with an electrophoretic mobility similar to that of Hb S. In addition, a band migrating cathodic to Hb A2 suggested the presence of a variant Hb A2 with a substitution in the alpha-chain, a fact that was later confirmed by structural analysis. An unusual feature of Hb Evanston is its low percentage; less than 10% occurs in the hemolysate. Studies indicate that the variant is not unstable, but there appears to be a defect in globin-chain synthesis. Gene mapping also shows that it is associated with the alpha-thalassemia-2 gene. The variant has high oxygen affinity with normal cooperativity and a normal Bohr effect. The combination of Hb Evanston with alpha-thalassemia-2 produced anemia in this black family.
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PMID:Hemoglobin Evanston: alpha 14(A12) Trp leads to Arg. A variant hemoglobin associated with alpha-thalassemia-2. 688 79

A series of 12 patients with beta-thalassemia who developed juvenile leg ulcers is described. The trophic skin changes and leg ulcers occurred after the age of 15 years. Usually the ulcer occurred after trauma over the predisposed medial aspect of the leg. In four out of seven females, the trophic changes deteriorated during or following pregnancy. The development of trophic changes and subsequent leg ulcers is not related to the severity of the anemia or to the patients' transfusion requirements, but may be related to high fetal hemoglobin concentration. The ulcers are slow to heal and tend to recur. Multiple skin-grafting operations are required in order to achieve satisfactory coverage of the ulcers. Since tissue hypoxia may be the underlying pathophysiology, the use of topical hyperbaric oxygen chamber may be beneficial in the treatment of thalassemic leg ulcers.
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PMID:Juvenile leg ulceration in beta-thalassemia major and intermedia. 703 14

This review primarily deals with methods for separations of hemoglobins. An introduction considers electrophoretic methods as well as those involving isoelectric focusing and chromatography. The main advantages or disadvantages of each procedure are discussed after each technical description. The chromatographic methods are mainly limited to those used in clinical biochemistry. The second section treats the main diagnostic problems typically met with in the field of the hemoglobinopathies and deals successively with the diagnosis of hemoglobinopathies in the adult and the newborn. Numerous variants have been described in the adult, and among them Hb-S and Hb-C variants are the most frequent. Unstable or high oxygen affinity variants of hemoglobin are also considered. Finally, a new strategy for diagnosis is proposed. A special section is devoted to the diagnosis of thalassemia syndromes. The prenatal diagnosis of hemoglobinopathies is also discussed in some detail with a view to preventing the birth of homozygous children. This update ends with a chapter on the interest of the assay of hemoglobins A1c in the pathology of diabetes mellitus.
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PMID:An update on electrophoretic and chromatographic methods in the diagnosis of hemoglobinopathies. 703 6

An Indian family is described in which the father has a delta chain abnormal hemoglobin which is the result of a mutation of the delta gene in cis to a beta-thalassemia heterozygosity. The abnormality concerns a substitution of the Asp residue in position 99 (G1) by an Asn residue. A similar substitution has been found in the beta chain of Hb Kempsey (alpha 2 beta 2 99 Asp replaced by Asn). The observed abnormality results in a greatly increased oxygen affinity of this newly discovered Hb A2 variant.
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PMID:Hb A2-Canada or alpha 2 delta 2 99(G1) Asp replaced by Asn, a newly discovered delta chain variant with increased oxygen affinity occurring in cis to beta-thalassemia. 712 31

The levels of 2,3-DPG and the value of P50 were determined in unselected, clinically healthy, typical beta-thalassemia heterozygotes and normal controls. Values of 2,3-DPG in the heterozygotes are significantly elevated compared to normals (when expressed per gram of hemoglobin or per volume of red cells) and much higher than their mild hemoglobin deficit would explain; they are elevated even in selected heterozygotes presenting normal hemoglobins levels. These 2,3-DPG values, when expressed per number of erythrocytes, are within normal limits. In parallel, oxygen affinity is lower, as the P50 value is displaced to the right by 2 mmHg above the normal mean, thus assuring adequate tissue oxygenation. The findings suggest that the high 2,3-DPG values of the beta-thalassemia heterozygotes are not determined solely by anemic hypoxia; it is more likely that the microcytic erythrocytosis of heterozygous beta-thalassemia is the cause of this increase. The resulting lower oxygen affinity leads to a decreased stimulation of erythropoiesis and hence to its regulation at lower hemoglobin levels. Accordingly we suggest that the beta-thalassemia trait is a pseudo-anemia, because it is unlikely that these heterozygotes are unable to reach normal hemoglobin values by increasing erythrocyte output.
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PMID:[Anemia 2,3-DPG and tissue oxygenation in beta-thalassemia heterozygotes]. 716 85

An abnormal human hemoglobin was found in association with beta-thalassemia in a hemolysate from an 11-year-old healthy child living in Bologna (northern Italy). Structural studies demonstrated a previously unreported amino acid substitution, beta 61 (E5) Lys replaced by Met (this is an external residue). The new variant has been named Hb Bologna, and is characterized by a reduced oxygen affinity. Family studies indicated that the variant had been inherited from the father, a 41-year-old male of Southern Italian origin. Also, a brother of the propositus was found to be an abnormal Hb carrier.
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PMID:Hemoglobin bologna (alpha 2 beta 2 61 (E5) lys replaced by met). An abnormal human hemoglobin with low oxygen affinity. 722 7

The risk of altitude-induced hypoxemia causing painful crisis was determined in a group of 45 predominantly adult patients with sickle cell disease. The patients were divided into two groups: those with hemoglobin (Hb) SS and those with Hb SC or Hb S beta-thalassemia. Altitude exposures were divided into airplane travel and mountain visits, and the latter subdivided into stays at 4,400 or 6,320 ft. The average risk of crisis was higher for both groups while in the mountains (37.9 percent and 56.6 percent, respectively) than it was during airplane travel (10.8 percent and 13.5 percent, respectively). The latter group had more splenic crises than the former group and also had a greater risk at 6,320 ft (65.9 percent) than at 4,400 ft (20.0 percent). Patients with sickle cell disease are at high risk of crisis in the mountains, and we advise those with intact spleens to breathe supplemental oxygen during air travel.
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PMID:Risk of altitude exposure in sickle cell disease. 734 Jan 30


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