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)

Two unrelated families are reported in which beta-thalassemia trait occurred with a heterozygosity of Hb G-Philadelphia (alpha2 68(E17)Asn leads to Lys beta2) in one family and with Hb Rampa (alpha2 95(G2)Pro leads to Ser beta2) in the other. The percentage of Hb G-Philadelphia was not influenced by the simultaneous presence of a beta-thalassemai determinant, but that of Hb Rampa was descreased from 20% in the simple heterozygote to about 6% in persons with the Hb Rampa-beta-thalassemia combination. Data from in vitro recombination experiments with isolated alpha X, alpha A, and beta A chains, with heme attached, indicated a preferential formation of Hb A over Hb Rampa but not over Hb G-Philadelphia in conditions of relative beta-chain deficiency. This suggests that the rate of assembly of monomers to form dimers or tetramers can be an important mechanism of controlling the quantity of certain hemoglobin variants with critical substitutions in heterozygotes.
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PMID:Variability in the interaction of beta-thalassemia with the alpha-chain variants Hb G-Philadelphia and Hb Rampa. 68 17

The influence of malaria on the hemoglobin A2 (Hb A2) level in humans was studied in a series of 94 imported cases in Belgium. Sixty-nine of the patients were natives of Western European countries, their results are reported separately since their origin and the results of their hematological examination made it unlikely that they carried the beta-thalassemia trait. The Hb A2 level of the 94 malaria patients (mean 2.76%; S.D. 0.51%) was not statistically different from that found in 60 healthy controls (mean 2.70%; S.D. 0.38%; P greater than 40). Likewise the level of the 65 Western European patients was not statistically different from that of the same controls (mean 2.81%; S.D. 0.42%; P greater than 0.10). There was also no significant difference between the level in patients infected with a particular species of Plasmodium and that of the controls. No correlation was found between the Hb A2 level and the intensity of the parasitemia or the concentration of total hemoglobin in the blood. These results are discussed in comparison with the divergent ones obtained by others and it is suggested that malaria has no significant influence on the results of surveys for the prevalence of beta-thalassemia in regions of malaria endemicity.
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PMID:Hemoglobin A2 levels in malaria patients. 68 38

Sickle cell anemia and other severe sickle cell disorders (hemoglobin SC and hemoglobin S-thalassemia) are known to complicate surgical procedures in susceptible patients. Although transfusions have been used preoperatively to increase the packed cell volume, we have recently used the method of partial exchange transfusion in the treatment of patients with these disorders in the preoperative period. Forty-two patients with significant sickle cell hemoglobinopathies underwent operative procedures on various surgical services. The goal was to obtain a hemoglobin A percentage of 40 or above in each case, and this required 480 to 1,150 c.c. of buffy coat poor washed red cells (mean 820 c.c.). The number of complications in the intraoperative and postoperative period in this study was compared to those found in the literature. There was a significant decrease in morbidity and mortality rates noted with the use of these transfusions. There appeared to be a great advantage on a cost-benefit ratio, as well as an improvement in the physiologic state of the patient. Although the results of this study show significant improvement over previous investigations, there are many facets unknown concerning the use of this modality under these and other conditions. Therefore, further investigation of this method and restriction of the method of Level III referral centers is advocated until enough patients have been studied to assess the long- and short-term complications of the procedure.
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PMID:Use of partial exchange transfusion preoperatively in patients with sickle cell hemoglobinopathies. 69 86

In order to determine if mutant hemoglobins can be identified by relatively simple methods, a Working Group of the ICSH Expert Panel on Abnormal Hemoglobins and Thalassemia analyzed 17 hemolysates containing 14 different mutant hemoglobins by four electrophoretic methods: (1) cellulose acetate in alkaline buffers, (2) citrate agar pH 6.0, (3) urea 2-mercaptoethanol buffer pH 8.9, and (4) urea 2-mercaptoethanol buffer pH 6.0. The examined mutants included several of great numerical and clinical importance as well as some rare ones, namely, HbS, C, D Los Angeles (Punjab), E, G Philadelphia, N Baltimore, and O Arab; also Hb Ft. Worth, Montgomery, Winnepeg, Rush, Q India, Bethesda, and Lepore. Comparative mobilities of these hemoglobins in all of the methods are presented here. The combined data permit their presumptive identification, often with a high degree of specificity. The system has been applied in Iran, where the four prevalent mutants can be differentiated by these methods, at considerable saving of time and resources previously expended on structural analyses. It is proposed as a basis for an ICSH Tentative Standard. There is little doubt that this presumptive identification of hemoglobin variants by simple electrophoresis will be improved or complemented by the introduction of newer techniques, such as immunologic analysis. However, for the present and for some time to come, the system outlined here should be found valuable. The present report does not concern itself with the numerous auxiliary techniques involved in the identification of abnormal hemoglobins-sickle-cell test, solubility tests, lability test--and no claim is made that the simple system described here eliminates these other techniques from the diagnostic armamentarium of the laboratory.
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PMID:Simple electrophoretic system for presumptive identification of abnormal hemoglobins. By the International Committee for Standardization in Hematology. 69 90

The structure, properties, genetics, and clinical and biochemical expression of hemoglobins Lepore (deltabeta) and anti-Lepore (betadelta) are described. In addition to the three Lepore variants (Lepore Hollandia, Lepore Baltimore and Lepore Washington) at least four anti-Lepore variants (Miyada, P Nilotic (P Congo), Coventry and Lincoln Park) are known at the present time. All known hemoglobins Lepore and anti-Lepore are products of non-homologous crossing-over between the delta and the beta genes. Although the Hb Lepore condition is expressed phenotypically and clinically as beta thalassemia, the presence of about 10% of Hb Lepore distinguishes the condition hematologically from beta thalassemia. Data on the hematological and biochemical expression of this hemoglobinopathy are presented. In contrast to the anemia in the Lepore condition, there is no phenotypic evidence of thalassemia in persons with hemoglobin anti-Lepore, because no beta chain deficiency accompanies the latter condition. Although no adequate explanation has been advanced concerning the factors which maintain a low synthesis of the Lepore and anti-Lepore chains, it has been suggested that multiple rare codons may introduce rate-limiting steps or that the deltabeta and betadelta mRNAs may be unstable. Data on the geographical distribution and structural identification of Hb Lepore are presented.
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PMID:Hemoglobins Lepore and anti-Lepore. 70 Oct 81

In this study the clinical and hematological characteristics, the transmission pattern and the relative rates of globin chain synthesis were determined in the members of four Sardinian families with 14 patients affected by hemoglobin H disease. The severity of hemoglobin H disease in Sardinian subjects shows a high degree of variability. Clinically it usually appears intermediate between the hemoglobin H disease found in Oriental and Negro populations. The alpha/beta specific activity ratio was 0.42 +/- 0.10 indicating an analogous biochemical defect like that described in the Chinese. On the basis of hematological data and alpha/beta ratio, the genetics of hemoglobin H disease in Sardinians seem to follow a pattern similar to that observed in Orientals: one parent showing alpha-thalassemia-1 trait and the other alpha-thalassemia-2 trait. Parent offspring transmission of hemoglobin H disease did occur in 2 out of 6 hemoglobin H matings with spouses carrying the alpha-thalassemia-1 gene. This observation indicates either a high frequency of alpha-thalassemia trait in Sardinians or a high incidence of inbreeding. In one family the mating of a patient with hemoglobin H disease and a normal person produces 6/6 offspring with alpha-thalassemia-1. The genetic implications of this transmission pattern are discussed.
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PMID:Hemoglobin H disease in Sardinia: phenotypic and genetic observations. 70 Oct 89

A number of varieties of thalassemia were found to be common in the Vancouver area and in other parts of British Columbia. Of 3117 patients whose blood samples were studied by hemoglobin electrophoresis at the Vancouver General Hospital between Jan 1, 1965 and June 30,1977, 813 had the beta-thalassemia trait, 18 had homozygous beta-thalassemia, 97 had alpha-thalassemia trait, 24 had hemoglobin H disease and 14 had miscellaneous variants. Eight patients had interactions of beta-thalassemia with hemoglobin S,C, D, O arab or Vancouver, and one patient had alpha thalassemia associated with hemoglobin Constant Spring. Twelve other variants were noted. They included hemoglobins B2, E, Q, GHsi Tsou, J Bangkok, British Columbia, KOLN, Lepore, Rampa, Tacoma, St. Claude and an unidentified alpha-chain variant.
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PMID:Hemoglobinopathies in a hospital population in Vancouver. 70 69

On 20 consecutive work days during four weeks, one technologist performed 24 microchromatographic determinations of hemoglobin A2 (Hb A2) by each of four methods: the Efremov procedure requiring Tris/HCl buffer, the original Huisman technique with use of glycine developer, and two commercial test kits in which a modified glycine developer is used. The bloood samples tested were obtained from 12 adults with no hematological abnormality and from 12 beta-thalassemia carriers previously diagnosed by familial and hematologic studies. Results by the first method and the two commercial kits (one from Helena Laboratories and one from Isolab, Inc.) did not differ significantly in precision for either the normal or beta-thalassemia trait samples. For both sample types, the second method yielded larger coefficients of variation than those obtained with the other methods. Moreover, the second method was the only one with which values overlapped for normal samples and samples with above-normal Hb A2 concentrations.
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PMID:Microchromatographic methods for hemoglobin A2 quantitation compared. 71 69

A 13-year-old Thai female with hemoglobin E-beta-thalassemia was evaluated for anemia and splenomegaly. Globin chain synthesis in a whole cell system revealed an absence of betaA chains and excessive alpha chains. The alpha/betaE + gamma ratio was 1.26 in bone marrow and 1.90 in peripheral blood. The average gamma/betaE ratio in bone marrow and peripheral blood was 0.36 compared to peripheral blood concentrations of 49% hemoglobin E and 51% hemoglobin F. Homologous red cell 51Cr half-life increased from 22.7 days to 32.8 days after splenectomy. Total circulating hemoglobin increased from 112.9 to 149.7 g. Endogenous carbon monoxide productive (Vco) as a measure of total heme catabolism decreased from 2.00 to 1.54 mumol/hr/kg. Ineffective erythropoiesis was manifested by an increased Vco/Vheme-c ratio of 7.52.
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PMID:Splenic sequestration and ineffective erythropoiesis in hemoglobin E-beta-thalassemia disease. 72 94

In a cooperative intrastate program based upon experience with sickle-cell anemia screening, the authors explored the feasibility of applying hemoglobin electrophoresis for detection of beta-thalassemia gene carriers. Initially, blood samples collected in capillary tubes were analyzed by cellulose acetate electrophoresis with densitometric quantitation of hemoglobin A2 (Hb A2), followed by selective spectrophotometric quantitation. This approach proved insufficiently specific or reproducible. Follow-up hematologic and family studies of presumptive beta-thalassemia gene carriers indicated that coordinate measurement of erythrocytic indices and Hb A2 values would have discriminated a subpopulation with a high incidence of beta-thalassemia trait more specifically. This approach was tested prospectively by the use of 731 venous blood samples collected in a county with a large population of Mediterranean ancestry. Of 31 individuals (4.2%) with presumptive thalassemia trait, 13 returned for a repeat testing, and the initial results for 11 were confirmed. These findings lend support to an empirical screening sequence suggested by Pearson (erythrocytic indices followed by Hb A2 quantitation), but they also indicate that a significant subpopulation of beta-thalassemia gene carriers with limited phenotypic expression may elude detection in any single-pass approach.
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PMID:Population screening for beta-thalassemia minor. Report of cooperative trials based on two approaches. 72 71


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