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)

Northern Nigeria is an endemic area for sickle haemoglobin (HbS), and it is common practice in many hospitals to accept blood for transfusion from donors with sickle cell trait (HbAS). In 212 healthy HbAS blood donors, the proportion of HbS was found to range between 24-47%. The HbS levels less than 38% were presumably due to the interaction of sickle-cell gene with the alpha + thalassaemia gene. Low HbS levels and presumed alpha + thalassaemia were associated with significant microcytosis and relatively low Hb A2 and Hb F, but differences were minimal. Carriers of sickle cell trait, with or without alpha + thalassaemia, appear to be acceptable as blood donors. Beta thalassaemia was not detected amongst 710 blood-donors.
East Afr Med J 1989 Dec
PMID:Haematological status of blood-donors with sickle cell trait and alpha thalassaemia in northern Nigeria. 261 14

Haemoglobin fractionation in 27 subjects with sickle cell trait revealed 12 (44%) with sickle cell haemoglobin less than 35 per cent (23.4-34.2%, mean 30.4 +/- 3.3%) suggesting an association of alpha thalassaemia. Electrophoresis of 91 samples of cord blood revealed demonstrable amounts of haemoglobin Bart's in 7 (7.7%); six between 5 and 10 per cent and one with less than 2 per cent. It appeared that the six infants with higher amounts of haemoglobin Bart's were homozygous for alpha-thalassaemia + (-a/-a) genotypes and one was heterozygous for alpha-thalassaemia + (-a/aa) Results of haemoglobin electrophoresis done on 2754 blood samples analysed from hospital records, retrospectively did not reveal haemoglobin-H and haemoglobin Constant Spring in any of the samples.
Indian J Med Res 1989 Dec
PMID:Detection of alpha thalassaemia in sickle cell trait patients by Hb-Bart's screening & quantitation of Hb-A & Hb-S. 262 14

Hereditary spherocytosis is still difficult to diagnose in some situations due to the existence of subclinical expressions and the lack of an accurate test with high sensitivity and specificity. Recently, Vettore et al. described the so-called 'Pink test' as an easy method with the highest reproducibility and sensitivity. Herein, we present our experience with the 'Pink test' in the diagnosis of 16 previously diagnosed hereditary spherocytosis patients comparing the results with those obtained in 96 healthy controls, 41 beta-thalassaemias, 9 autoimmune haemolytic anaemias, 8 chronic hemoproliferative syndromes and 2 patients with pyruvate kinase deficiency. We also present a modification of the original 'Pink test' in which a small sample of blood (200 microL) obtained by finger-prick (or heel puncture in newborns and infants) is mixed with the hemolyzing solution of the 'Pink test' within the first three hours after blood drawing. Elevated correlation coefficients (r = 0.75-0.96) between both methods have been obtained comparing the percentage of final haemolysis in 25 healthy controls, 21 beta-thalassaemia minor and 9 hereditary spherocytosis patients.
Sangre (Barc) 1989 Dec
PMID:[The modified "pink test" in the diagnosis of hereditary spherocytosis]. 262 27

A study of the distribution of alpha-thalassemia in Papua New Guinea (PNG) was carried out by DNA analysis. A total of 664 DNA samples were screened for alpha-thalassemia 2 and alpha-thalassemia 1 caused respectively by either deletion of one or both of the duplicated alpha-globin genes. alpha-Thalassemia 2 was detected in high frequencies in coastal and lowland regions where malaria has been holo- to hyperendemic but in low frequencies in non-malarious highland regions. The highest frequency was observed in the north coast of PNG. The distribution of alpha-thalassemia 2 seems to be in accordance with other conditions such as ovalocytosis and G6PD deficiency which are also prevalent in this population, suggesting that they may interact in protection against malaria. However, it appears to be negatively correlated with beta-thalassemia and alpha-thalassemia 1, the latter being extremely rare in this population. Analysis of the types and subtypes of the single alpha-globin gene deletion revealed a predominance of the -alpha 4.2 type in general, except in some regions in the south where the -alpha 3.7 type is prevalent. The -alpha 3.7 I subtype is the common form of the -alpha 3.7 deletion in the PNG mainland. The -alpha 3.7 III subtype, previously reported to be unique in Melanesians and Polynesians, was detected in an offshore island of PNG. However, this subtype is very rare in Melanesians from the PNG mainland.
Hum Genet 1986 Dec
PMID:Alpha-thalassemia in Papua New Guinea. 287 71

The use of busulphan and cyclophosphamide permitted engraftment in 44 of 49 children receiving 'displacement' bone marrow transplants. Three patients who received T-cell-depleted marrow cells from HLA-haploidentical donors failed to engraft and other graft failures were due to inadequate induction dosage. Our standard schedule comprises busulphan 80 mg/m2/day x 4 days (adjusted if necessary to a minimum of 4 mg/kg/day or a maximum of 5 mg/kg/day) followed by cyclophosphamide 2 g/m2/day x 4 days but reduced so as not to exceed 75 mg/kg/day, a maximum dose preferred for patients with full marrows (e.g. those with thalassaemia major). Of 21 recipients of mixed lymphocyte culture (MLC)-negative donor marrow cells with full engraftment at 100 days, there were three late rejections. Of patients transplanted with marrow from MLC-positive donors, one had late rejection after cyclosporin A toxicity had necessitated withdrawal of the drug at day + 146 but six other patients, whose cyclosporin A was stopped routinely 1 year, remain well with full grafts. Ten patients died as a result of graft-versus-host disease. We are therefore exploring new approaches to T-cell depletion and storing autologous marrow for use in the event of graft failure. If necessary, a second transplant with busulphan and cyclophosphamide is best performed at 3 months after full recovery of the host. We conclude that elective transplants can be performed successfully in children with normal immune function without the need for irradiation.
Bone Marrow Transplant 1986 Dec
PMID:Engraftment rates related to busulphan and cyclophosphamide dosages for displacement bone marrow transplants in fifty children. 297 9

Detailed restriction enzyme analysis of the DNA from a Chinese female showed that one of her chromosomes had a greater than 17.5 kb deletion of DNA, including the psi alpha, alpha 2, and alpha 1 globin genes, which is present in many Southeast Asians with an alpha-thalassemia-1 chromosome. Her "normal" chromosome had the expected cluster of alpha-like globin genes (5'-zeta-psi zeta-psi alpha-alpha 2-alpha 1-3'), but the segment of DNA between the two alpha globin genes was elongated by some 0.5-0.7 kb. Analyses of various restriction sites suggested that this normal variant of the human alpha globin gene complex is due to a crossover between a normal chromosome with (alpha alpha) and a chromosome with an alpha-thalassemia-2 (-alpha 3.7) and an -alpha 2 alpha 1-hybrid gene.
Hum Genet 1986 Dec
PMID:An elongated segment of DNA observed between two human alpha globin genes. 302 76

Prophylactic blood transfusion has come to be regarded as necessary in the treatment of patients with sickle cell disease during pregnancy. Because of the risks associated with blood products and reports of successful outcomes without the use of blood transfusion, we conducted a prospective randomized controlled study of this issue. Seventy-two pregnant patients with sickle cell anemia were randomly assigned to one of two treatment groups: 36 received prophylactic transfusions of frozen red cells, and 36 received red-cell transfusions only for medical or obstetric emergencies. Twenty-eight patients with sickle cell anemia who did not qualify for randomization (mainly because they had other medical disorders), 66 with sickle cell-hemoglobin C disease, and 23 with sickle cell-beta-thalassemia were also followed and received transfusions only for emergencies. There was no significant difference in perinatal outcome between the offspring of mothers with sickle cell disease who were assigned to treatment with prophylactic transfusions and those who were not (15 vs. 5 percent). The occurrence of a perinatal death in a previous pregnancy and the presence of twins in the present pregnancy were two major risk factors for an unfavorable outcome; when they were present, perinatal mortality was 50 percent. Perinatal mortality was somewhat higher in the two groups that were randomized than in the three groups that were not. Prophylactic transfusion significantly reduced the incidence of painful crises of sickle cell disease (P less than 0.01) and substantially reduced the cumulative incidence of other complications of this disorder (P = 0.07). Other medical and obstetric complications occurred with nearly equal frequency in the two randomized groups. Increases in costs, the number of hospitalizations, and the risk of alloimmunization were disadvantages of prophylactic transfusion. We conclude that the omission of prophylactic red-cell transfusion will not harm pregnant patients with sickle cell disease or their offspring.
N Engl J Med 1988 Dec 01
PMID:Prophylactic red-cell transfusions in pregnant patients with sickle cell disease. A randomized cooperative study. 263 74

Blood, pH and bicarbonate were examined in 40 normal subjects and in 53 patients with anemia. Included were 28 patients with thalassemia, 18 with aplastic anemia and seven with iron deficiency anemia. Mean increases in pH of 0-0.04 and decreases in HCO3 of 2.3-3.5 mEq/L were observed. Changes were not significantly affected by the degree of erythropoiesis or by the severity of the anemia and were essentially the same in the three groups of patients studied. Typical changes of a mild, uncompensated alkalosis were also produced on four occasions in one transfused thalassemic patient.
Am J Med Sci 1987 Dec
PMID:A mild uncompensated alkalosis in anemia. 312 64

The main iron chelator used for transfusional iron overload is desferrioxamine, which is expensive, has toxic side effects, and has to be given subcutaneously. An orally active iron chelator is therefore required. The effects of oral 1,2-dimethyl-3-hydroxypyrid-4-one on urinary iron excretion were studied in eight patients who had received multiple transfusions: four had myelodysplasia and four beta thalassaemia major. Different daily doses of the drug up to 100 mg/kg/day, alone or in combination with ascorbic acid, were used. In three patients with thalassaemia the effect of the drug was compared with that of subcutaneous desferrioxamine at the same daily dose. In all eight patients a single dose of oral 1,2-dimethyl-3-hydroxypyrid-4-one resulted in substantial urinary iron excretion, mainly in the first 12 hours. Urinary iron excretion increased with the dose and with the degree of iron loading of the patient. Giving two or three divided doses over 24 hours resulted in higher urinary iron excretion than a single dose of the same amount over the same time. In most patients coadministration of oral ascorbic acid further increased urinary iron excretion. 1,2-Dimethyl-3-hydroxypyrid-4-one caused similar iron excretion to that achieved with subcutaneous desferrioxamine at a comparable dose. In some cases the iron excretion was sufficiently high (maximum 99 mg/day) to suggest that a negative iron balance could be easily achieved with these protocols in patients receiving regular transfusions. No evidence of toxicity was observed on thorough clinical examination or haematological and biochemical testing in any of the patients. None of the patients had any symptoms that could be ascribed to the drug. These results suggest that the oral chelator 1,2-dimethyl-3-hydroxypyrid-4-one is as effective as subcutaneous desferrioxamine in increasing urinary iron excretion in patients loaded with iron. Its cheap synthesis, oral activity, and lack of obvious toxicity at effective doses suggest that it should be developed quickly and thoroughly tested for the management of transfusional iron overload.
Br Med J (Clin Res Ed) 1987 Dec 12
PMID:Effective chelation of iron in beta thalassaemia with the oral chelator 1,2-dimethyl-3-hydroxypyrid-4-one. 312 80

Human alpha-thalassemia-2 genotype -alpha 4.2 is the result of meiotic recombination between two 1.3 kb long, homologous DNA segments, X(alpha 2) and X(alpha 1), located in the adult alpha globin locus. The two segments can also undergo intramolecular recombination on extrachromosomal vectors transfected into mitotically dividing primate cells (COS 7). The existence of a gradient of sequence divergence between X(alpha 2) and X(alpha 1) makes them an interesting system to study the relationship between efficiencies of homologous DNA recombination and the extent of dispersed and localized base mismatches. By partial restriction mapping and DNA sequencing of plasmids recombined in COS 7 cells and rescued from bacteria HB 101, we have determined the distribution of recombinational resolution sites along the two X blocks. Most, if not all, of the homologous recombination events between the two X blocks appear to be single crossing-over without efficient gene correction or repair of base mismatches. The distribution of the sites of recombinational resolution is inversely correlated with that of the gradient of sequence divergence, with only approximately 7% of the X recombinants resolved within the 3' third of the X blocks where two diverged Alu family repeats reside. The Alu sequence within which one of the X recombinants resolved is homologous to a previously characterized alpha thalassemia deletion point.
Nucleic Acids Res 1988 Dec 09
PMID:Recombinational resolution in primate cells of two homologous human DNA segments with a gradient of sequence divergence. 314 5


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