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

The sinusoidal fetal heart rate pattern has been reported to be associated with fetal anemia, hypoxia, administration of alphaprodine while, in other cases, it has been followed by good fetal outcome. In this case study fetoscopy was performed in a patient with thalassemia trait for prenatal diagnosis of thalassemia. Following the insertion of the trocar, bloodstained amniotic fluid was aspirated which resulted to be all fetal in origin. Estimation of feto-maternal hemorrhage was 5.7 ml while the amount of intra-amniotic bleeding could not be assessed. Fetal heart rate, which was recorded throughout fetoscopy, showed a sinusoidal pattern starting two minutes after the fetal hemorrhage which lasted more than ten minutes. Two hours later the fetal heart rate was normal. The pregnancy continued uneventfully and a healthy female baby weighing 3100 g was delivered at 38 weeks' gestation. Review of the literature suggests that a sinusoidal pattern may be caused either by a hemodynamic disturbance or fetal acidosis. In any case it does not always indicate impending fetal death.
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PMID:Sinusoidal rhythm caused by fetal hemorrhage during fetoscopy. 672 94

We have assessed the effects of screening and genetic counseling for beta-thalassemia trait on knowledge, attitudes, and behavior in a prospective, controlled study of randomly selected adult members of a health maintenance organization. We report here that knowledge of manifestations and of inheritance of thalassemia, previously reported to be high immediately after counseling, were well maintained at 2 and 10 months following counseling. There was no detectable impairment of self-concept. Marital adjustment improved, and sexual activity increased significantly. Mood, assessed immediately before and after counseling, showed no undesirable changes. A patient-structured counseling method, designed to minimize negative psychological effects via discussion of feelings, was not superior to conventional and programmed methods, described in our previous reports, in terms of learning or attitude change.
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PMID:Screening and genetic counseling for beta-thalassemia trait in a population unselected for interest: comparison of three counseling methods. 673 41

A case of Hb H disease from Algeria was studied at the genetic and molecular level in order to delineate the pattern of alpha-thalassemia in the Mediterranean population. The family study indicated that both parents had the hematological and clinical manifestation of alpha-thalassemia trait and that the affected sibling had homozygous alpha-thalassemia with 5.6% Hb H, microcytosis and an alpha-/non-alpha-biosynthetic ratio of 0.64. Hybridization in globin cDNA alpha excess suggested that the molecular defect responsible for this form of alpha-thalassemia is a partial deletion of the haploid stock of alpha-globin genes. The Algerian case of Hb H disease studied thus differs from Asian and Negro cases by the mode of inheritance of the alpha-thalassemia mutation involved.
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PMID:Hemoglobin H disease from Algeria: genetic and molecular characterization. 679 34

Microcytic red blood cells (RBC) are commonly encountered in clinical medicine and are caused by disorders of heme synthesis [usually iron deficiency anemia (IDA) or anemia of chronic disease (ACD)] or disorders of globin synthesis (usually thalassemia syndromes or HbE). Using the clinical history and standard laboratory tests (hematocrit, per cent saturation of transferrin (% sat), serum ferritin, Hb electrophoresis, HBA2, and HbF) we classified 198 adults with microcytic RBC as follows: 48 IDA, 11 probable IDA, 11 iron-deficient erythropoiesis without anemia, 13 ACD, 42 alpha-thalassemia trait, 35 probable alpha-thalassemia trait, 20 beta-thalassemia trait, and 15 unclassified. In addition, we demonstrated that the FEP test reliably (83-90% of the time, depending on FEP methodology) classifies microcytic RBC states into disorders of heme synthesis vs. disorders of globin synthesis. Because of reliability and ease of measurement, we recommend the hematofluorometer FEP as the first step in the clinical laboratory evaluation of microcytic RBC disorders in both adults and children.
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PMID:Free erythrocyte protoporphyrin (FEP) II. The FEP test is clinically useful in classifying microcytic RBC disorders in adults. 684 56

In humans the alpha-globin genes are duplicated and closely linked. Whereas individuals heterozygous for most alpha-chain mutations possess approximately 25% abnormal hemoglobin, heterozygotes for the alpha-chain variant Hb G Philadelphia synthesize either 33% or 50% Hb G. Both variable gene dosage and interaction with alpha-thalassemia have been proposed to explain this observation. To differentiate between these models, we have performed restriction endonuclease mapping and hematological studies on individuals with Hb G from four families. In every case the alpha G locus was carried on an EcoRI or EcoRI + BamHI fragment approximately 4 kilobases shorter than that bearing the two linked alpha A loci of hematologically normal individuals. Bgl II digestion revealed that the alpha G gene is the only alpha locus on the affected chromosome. Erythrocyte indices and alpha/beta synthesis ratios indicated that the alpha G chromosome confers alpha-thalassemia. In addition to the alpha G gene, subjects who synthesized 33% Hb G possessed two alpha A genes on the homologous chromosome and exhibited the mild form of alpha-thalassemia trait ("silent carrier"). Subjects who synthesized 50% Hb G possessed a single alpha A gene trans to the alpha G locus and displayed the more pronounced form of alpha-thalassemia trait. One subject, who synthesized 100% alpha G chains and had Hb G-Hb H disease, was found to have a single nonfunctional alpha gene trans to the alpha G gene. Thus the proportion of Hb G synthesized by heterozygotes is determined by interaction with alpha-globin gene deletions cis and trans to the alpha G locus.
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PMID:Proportion of hemoglobin G Philadelphia (alpha 268 Asn leads to Lys beta 2) in heterozygotes is determined by alpha-globin gene deletions. 693 89

A 63-year-old man of italian origin with severe heterozygous beta-thalassemia whose clinical condition deteriorated after splenectomy is described. The alpha/beta synthesis ration in the peripheral blood was 3.02 +/- 0.56 and in the bone marrow 1.43. The free alpha-chain pool comprised 73% of the total radioactive alpha-globin in the peripheral blood and 68% in the bone marrow. RBC membranes isolated from erythrocytes incubated in the presence of 14C-leucine were practically devoid of nascent beta-chains with an alpha/beta ratio of 5.12 +/- 1.47, significantly higher than that present in the corresponding hemolysate. RBC membranes from this patient, compared to control membrane preparations, showed increased proteolytic activity directed against tetrameric hemoglobin and beta-hemoglobin chains, with concomitant decreased catabolism of alpha-hemoglobin chains. RBC membranes from individuals with mild beta-thalassemia trait and from transfused patients with homozygous beta-thalassemia degraded alpha-hemoglobin chains more efficiently than those from the patient described. The data suggest that decreased degradation of the alpha-chain by RBC membranes from this patient might lead to progressive accumulation of this polypeptide and expansion of the free alpha-chain pool, which, in turn, may be responsible for the severity of the clinical picture.
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PMID:Abnormal red cell membrane proteolytic activity in severe heterozygous beta-thalassemia. 703 10

Utilizing restriction endonuclease mapping and molecular hybridization we have determined the number and arrangement of the alpha-globin genes in members of an American Black family in which alpha-thalassemia is present. In addition to chromosomes bearing 0, 1 or 2 alpha-genes, an unusual chromosome bearing 3 alpha-globin genes was detected in 3 family members. In 2 family members the 3 alpha-globin gene chromosome was present opposite a chromosome containing a single alpha-globin gene; these cases represent the first reports of the alpha alpha alpha/-alpha genotype. The presence of the stigmata of "mild" alpha-thalassemia trait in one of these subjects indicates that the 3 alpha-gene chromosome probably does not direct the synthesis of significantly more alpha-globin chains than does the 2 alpha-gene chromosome.
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PMID:Interaction of chromosomes bearing 1, 2 or 3 alpha-globin genes in an American black family with alpha-thalassemia. 709 14

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

The separation of alpha, beta, G gamma and A gamma globin chains by reversed phase high pressure liquid chromatography has been studied using columns of octadecylsilyl-silica. All separations were performed in solvent mixtures of water and acetonitrile acidified with phosphoric acid or the hydrophobic ionpairing reagent trifluoroacetic acid. The addition of trifluoroacetic acid or the chaotropic agent NaClO4 to the mobile phase increased the resolution and the peak sharpness of the eluted globin chains. The use of decreasing gradients of TFA or NaClO4 and chromatography at 40 degree were useful steps for the separation of alpha and beta globin chains, a prerequisite for the successful application of this method for the prenatal diagnosis of beta-thalassemia. The beta/gamma synthetic ratio obtained from blood samples taken by fetoscopy from normal fetuses and fetuses with beta-thalassemia trait were measured simultaneously by CM-cellulose chromatography and high pressure liquid chromatography. The values obtained by HPLC were very similar but slightly lower than those obtained by CM-cellulose chromatography. The new method is fast and accurate and will prove to be useful for prenatal diagnosis involving globin chain separation.
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PMID:Reversed-phase high pressure liquid chromatography of globin chains: its application for the prenatal diagnosis of beta-thalassemia. 727 70

Providing adequate counseling of patients identified in genetic screening programs is a major responsibility and expense. Adults in a health maintenance organization, unselected for interest, were screened for beta-thalassemia trait as part of preventive health care. Counseling was provided by either a trained physician (conventional counseling) or by a videotape containing the same information followed by an opportunity to question a trained physician (programmed counseling). Immediately before and after counseling, knowledge of thalassemia, knowledge of genetics, and mood change were assessed by questionnaire. Comparable mood changes and similar learning about thalassemia and genetics occurred with both counseling methods. Thus, as judged by immediate effects on knowledge and mood, videotaped instruction can greatly reduce professional time required for genetic counseling and facilitate the incorporation of genetic screening into primary health care.
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PMID:Genetic counseling for beta-thalassemia trait following health screening in a health maintenance organization: comparison of programmed and conventional counseling. 732 62


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