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)

We have demonstrated that the extent of intracellular polymerization of deoxyhemoglobin S can be predicted from knowledge of intracellular hemoglobin concentration, composition and oxygen saturation. Furthermore, we have demonstrated that polymer, which appears to be the main determinant of abnormal red cell rheology, can be detected in sickle erythrocytes at high oxygen saturation values and is not significantly affected by membrane and other cellular constituents. Some of the factors which modify the pathophysiology of sickle cell anemia can be classified as genetic or cellular. To analyze in more detail the genetic factors, we examined 12 sickle syndromes. When the effects of these genotype differences are analyzed for their changes in hemoglobin composition and concentration, we found that polymer formation can account for 80% of the variation in hemolytic and clinical severity. Cell heterogeneity can also modify polymer formation. The premature increases in erythrocyte density (intracellular hemoglobin concentration) in sickle cell anemia increases polymerization tendency. Homozygous alpha-thalassemia in sickle cell patients reduces this increase in cell heterogeneity and improves the hemolytic aspect of the sickle cell disease. For homozygous sickle cell patients we find that the broader density distributions (higher degree of cell heterogeneity) are associated with those cell populations with greater tendency of polymer formation. However, the major utility of our knowledge of intracellular polymerization appears to be its value in defining quantitatively the goals of the major therapeutic approaches with respect to how much inhibition of polymerization would be necessary to achieve various levels of amelioration of disease processes. The primary determinant of the amount of polymer formation within the SS erythrocyte is the extent of oxygen saturation. We measured intracellular polymer formation in SS erythrocytes using carbon-13/proton double nuclear magnetic resonance. As the oxygen saturation is decreased below about 90% oxygen saturation, we begin to see the appearance of polymer which steadily increases with decreasing oxygen saturation. The total intracellular hemoglobin concentration also affects the amount of polymer formed. By examining polymer formation in fractionated subpopulations of SS erythrocytes at various density values (or intracellular hemoglobin concentrations) we demonstrated that the polymer fraction increased with increasing intracellular hemoglobin concentration for any given oxygen saturation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Intracellular polymerization of sickle hemoglobin: disease severity and therapeutic goals. 361 1

Hemoglobin Indianapolis was first described by Adams et al (1,2) as a very unstable variant with a phenotype similar to severe beta-thalassemia. We have also characterized this variant, but there are several differences in the clinical expression of the variant described in our report and those described in the original case. We found Hb Indianapolis to be unstable, but not to the extent that it could not be detected by routine testing. The four family members heterozygous for the variant were not anemic, showed normal hematologic values, and did not exhibit any severe clinical disadvantages, although there was slight reticulocytosis. The variant could not be resolved from Hb A on cellulose acetate (pH 8.4), but isoelectric focusing showed a double band in the region of Hb A that is probably the variant and Hb A. However, the variant chain was clearly evident by globin chain analyses in acid and alkaline buffers. The condition of additional blood samples did not allow us to determine the oxygen dissociation properties of the variant or the rates of globin chain synthesis.
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PMID:A case of hemoglobin Indianapolis [beta 112(G14) Cys----Arg] in an individual from Cordoba, Spain. 378 65

The activities of erythrocyte antioxidative enzymes were measured in two groups of patients with different genotypes of haemoglobin (Hb) H disease: 21 with alpha-thalassaemia 1 or alpha-thalassaemia 2 (alpha-thalassaemia 1/2) and 21 with alpha-thalassaemia 1/Hb Constant Spring (HbCS). They were compared with 21 normal subjects. Both genotypes of Hb H disease had increased activities of erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase when compared with those of controls. Comparison of the two genotypes showed that subjects with alpha-thalassaemia 1/Hb CS, the more severe disease, had higher SOD and GSH-Px activities but lower catalase activity than those with alpha-thalassaemia 1/2. This indicates that there are compensatory mechanisms in Hb H erythrocytes to cope with increased generation of oxygen free radicals as a result of increased excess beta chain.
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PMID:Comparison of erythrocyte antioxidative enzyme activities between two types of haemoglobin H disease. 380 16

Hemoglobin Kenitra is a new variant of the beta chain alpha 2 beta 2 69 (E13) Gly----Arg which does not produce any clinical symptoms. It is a slow-moving hemoglobin with a distinctive pattern of electrophoretic mobilities. The stability test was negative. Oxygen affinity studies were not performed. It was found in association with alpha-thalassemia and microcytosis, but paradoxically a high expression of the variant (55%) was observed.
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PMID:Hemoglobin kenitra alpha 2 beta 2 69 (E13) Gly----Arg. A new beta variant of elevated expression associated with alpha-thalassemia, found in a Moroccan woman. 383 75

Hb Knossos is a beta-chain variant (beta 27 Ser----Ala) that is unrecognizable by conventional separation methods but detectable by globin electrophoresis on urea-Triton X-acrylamide gels or by IEF. Hb Knossos is characterized by reduced synthesis and by interaction with beta-thalassemia, in which the double heterozygotes display typical features of thalassemia intermedia. The present paper summarizes the salient genetic, clinical, and biochemical characteristics of five such cases hitherto identified in three families along with the same features on 12 heterozygous Hb Knossos carriers. Hb Knossos displays a slightly decreased oxygen affinity; this factor may compensate in part for the severe anemia of the double heterozygotes. Hb Knossos is relatively rare in our population, since a prospective survey on 610 individuals has failed to disclose any heterozygotes. However, the mutation appears to have spread over the Mediterranean countries and may be more common elsewhere.
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PMID:Hemoglobin Knossos: a clinical, laboratory, and epidemiological study. 394 30

Hb Knossos (beta 27 (B9) Ala----Ser) is a recently discovered hemoglobin variant endowed with beta-thalassemic properties (1,2) We present the first homozygous cases. The propositus, a 19-year-old man is originally from northeast Algeria, but is unrelated to other Algerians who have hemoglobin Knossos. He has a beta(+)-thalassemia intermedia syndrome, including microcytic, hypochromic anemia, enlargement of the spleen, and an increase in the number of reticulocytes. The reduction of beta-chain synthesis is pronounced (alpha/non alpha:2.76). Whole cells containing Hb Knossos have a dramatically low oxygen affinity (P50:38 mm Hg). The propositus also has homozygous delta(0)-thalassemia. The chromosome carrying these mutations is characterized by the DNA haplotype I.
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PMID:Homozygous hemoglobin Knossos (alpha 2 beta 227(B9) Ala----Ser): a new variety of beta (+)-thalassemia intermedia associated with delta (0)-thalassemia. 395 38

We examined the extent to which the intracellular polymerization of sickle hemoglobin (HbS) can account for the severity of anemia and of vaso-occlusive manifestations in the various sickling syndromes. Polymer formation in sickle cell disease depends principally on the intraerythrocytic hemoglobin composition and concentration. In our studies, the polymer fraction in sickle red cells was determined from reported mean values for hemoglobin composition and mean corpuscular hemoglobin concentration (MCHC) in 12 groups of patients with sickle hemoglobinopathies (homozygotes for HbS, with and without coexistent alpha-thalassemia or various forms of the hereditary persistence of fetal hemoglobin [HPFH], beta+-, beta 0-, and delta beta-thalassemia, and heterozygotes for HbS with HbA). The calculated HbS polymer fractions at full deoxygenation and at physiologic oxygen saturation values were closely correlated with mean blood hemoglobin concentrations. In addition, polymer fraction correlated with the ranking of the sickling syndromes by vaso-occlusive severity. We find that polymer fraction accounts for about 80% of the variability in hemolytic and clinical severity. The method of analysis presented here provides a quantitative and systematic means of assessing the role of polymer formation in the pathophysiologic manifestations of the sickling syndromes. Our results support the hypothesis that the intracellular polymerization of HbS is the primary determinant of the severity of both anemia and clinical symptomatology in the sickle hemoglobinopathies.
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PMID:Hemoglobin S polymerization: primary determinant of the hemolytic and clinical severity of the sickling syndromes. 396 46

Superoxide anion production in resting and PMA- or zymosan-stimulated neutrophils was evaluated in 21 beta-thalassemia patients. The results were correlated with ferritin values, hepatitis B virus serum markers, liver pathology, immunoglobulin levels and T-cell subsets. Superoxide anion generation from resting or PMA-stimulated neutrophils was significantly higher in patients than in controls. On the contrary, zymosan-stimulated neutrophils showed reduced superoxide anion production. Increased superoxide anion production in resting neutrophils showed a significant correlation to the values of ferritin. In addition, patients with biopsy-proven chronic liver disease showed significantly increased ferritin levels and superoxide anion production as compared to the remaining patients. No correlation was observed between superoxide anion production and the presence or the absence of hepatitis B virus serum markers, immunoglobulin levels and T-cell subsets. A possible role of interreactions between iron and oxygen radicals in determining liver damage in beta-thalassemia patients is suggested.
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PMID:Changes in superoxide anion production in neutrophils from multitransfused beta-thalassemia patients: correlation with ferritin levels and liver damage. 633 Oct 44

We report on a 54 years-old male patient from North-Eastern Algeria who combines two hemoglobin variants that are associated with thalassemia-like disorders: Hb Lepore and Knossos (beta 27 Ala----Ser) (1, 2). A beta-thalassemia intermedia picture gradually developed and finally required splenectomy at the age of 53. Total absence of Hb A2 indicated that the beta Knossos gene is most probably flanked with a delta(0)-thalassemia gene. No DNA deletion additional to the Lepore deletion was found. Hb F was elevated (12.3%) with 24% G gamma Hb F. In whole cells, Hb Knossos, representing 70% of total hemoglobin, displayed a decreased affinity for oxygen (P50 = 35 mm Hg), a fact presumably accounting for the relatively good tolerance of the condition.
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PMID:The association of hemoglobin Knossos and hemoglobin Lepore in an Algerian patient. 646 99

A new hematologic syndrome with phenotypic features of mild Hb H disease was identified in three children from two unrelated black American families. Erythrocytes from each of these children contained Hb H (beta 4) and Hb Barts (gamma 4), as well as a slowly migrating hemoglobin fraction that made up 7-10% of the total hemoglobin. The parents of the affected children all showed mild thalassemia-like changes, with one of the parents in each family also expressing the variant hemoglobin; in the latter individuals the mutant alpha-chains made up less than 2% of the total, and were present mainly or exclusively in combination with delta-chains in the form of a slowly migrating Hb A2. Purified Hb Evanston showed an increased oxygen affinity, but its Bohr effect, cooperativity, and 2,3-diphosphoglycerate effect were normal. The mutant hemoglobin appeared to have normal stability to heat and to isopropanol, and the stability of its alpha-chain in an extended time course synthesis study also appeared to be similar to that of alpha A. However, the results from short-term globin synthesis studies, and from mRNA translation in vitro, suggest that the two types of alpha-chains were synthesized at relatively equal rates, with a major fraction of the newly synthesized variant alpha-chains undergoing rapid catabolism. The hematologic data taken in combination with DNA hybridization and globin synthesis findings indicate that the proposita in each of these families has the genotype--, alpha A/--, alpha Ev. These observations suggest that two separate mechanisms are contributing to the alpha-thalassemia-like expression of Hb Evanston : the newly synthesized alpha EV-chains are unstable and are subject to early proteolytic destruction; and the mutant alpha-allele is linked to an alpha-globin gene deletion.
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PMID:Hemoglobin Evanston (alpha 14 Trp----Arg). An unstable alpha-chain variant expressed as alpha-thalassemia. 672 58


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