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Biomedical subjects

P Wasi

Publications and source records attributed to P Wasi.

At least 37 records · Page 2Linked to original sources
PubMed1990

Thai G gamma (A gamma delta beta)zero-thalassemia and its interaction with a single gamma-globin gene on a chromosome carrying beta zero-thalassemia.

Clinical manifestations and hematologic data of thalassemia intermedia were observed in three siblings of a Thai family. Analyses of the hemoglobin of their parents and other siblings indicated that they inherited a delta beta-thalassemia gene from the father and a beta zero thalassemia gene from the mother. Globin gene mapping confirmed that they carry two abnormal beta-globin gene complexes. On one chromosome more than 70 kb of DNA was removed which resulted in G gamma (A gamma delta beta)zero-thalassemia. The deletion started at the Hind III site located just 3' to the G gamma gene, and extended downstream to a region recognized by the p3'N 2.8R probe which is located more than 45 kb from the 3' end of the beta gene. The other chromosome carried a beta zero thalassemia gene, and a 5 kb deletion between the G gamma and A gamma genes which produced a hybrid -GA gamma- gene. A synthetic oligonucleotide probe showed that this beta zero thalassemia arose from a C----T mutation at position 654 of IVS-II in the beta-globin gene.

Adolescent↗
PubMed1990

The molecular basis of beta-thalassemia in Thailand: application to prenatal diagnosis.

To enable the prenatal diagnosis of beta-thalassemia by direct detection of the mutant beta-globin genes, we have determined the spectrum of mutations causing this disease in Thailand. The techniques employed included a combination of synthetic oligonucleotide probe hybridization, direct sequencing of genomic DNA enzymatically amplified by the polymerase chain reaction, and cloning and sequencing of the beta-globin genes. A total of 116 beta-thalassemia genes from 78 Hb E/beta-thalassemia patients and from 19 homozygous beta-thalassemia patients were analyzed, and the mutation was characterized in 112/116 (97%) of them. Eleven mutations were found, of which four (-CTTT in codon 41/42, AAG----TAG in codon 17, C----T in position 654 of the IVS-2 region, and A----G in position -28 upstream of the beta-globin gene) accounted for 83%; two previously undescribed mutations have been identified. The spectrum of beta-thalassemia mutations is similar to that reported among the Chinese. However, within the Thai population itself, patients with homozygous beta-thalassemia show a wider spread of mutations in comparison with the Hb E/beta-thalassemia group, in whom the frameshift 41/42 mutation predominates at a frequency of 62%. This difference in distribution may reflect the difference in ethnic origin of the two groups. Characterization of these mutations should aid the planning of a prenatal diagnosis program for beta-thalassemia in Thailand.

Base Sequence↗
PubMed1989

The molecular basis of AE-Bart's disease.

AE-Bart's disease is a thalassemia intermedia resulting from the interaction between alpha-thalassemia and heterozygous Hb E. In this study we analyzed the alpha-globin genes of 25 patients designated as AE-Bart's disease by starch gel electrophoresis. Twenty-one cases had Hb Constant Spring in addition to Hbs E + A + Bart's, and the remaining four cases had only Hbs E + A + Bart's. DNA mapping revealed the alpha-globin genotype of alpha-thalassemia-1/alpha-thalassemia-2 in four patients who had Hbs E + A + Bart's, whereas the alpha genotype of the remainder is alpha-thalassemia-1/nondeletion alpha-thalassemia. The nondeletion alpha-thalassemia is Hb Constant Spring as indicated by starch gel electrophoresis. Hematologic data and hemoglobin analysis showed that Constant Spring-AE-Bart's disease is a more severe clinical syndrome than AE-Bart's disease.

Adolescent↗
PubMed1988

Cord blood study on beta-thalassemia and hemoglobin E.

We describe hematologic data from 18 newborn infants including follow-up data. Of these, ten were the offspring of patients with beta-thal/Hb E disease and the remainder were infants who were found to have a decrease in red cell osmotic fragility during a random cord blood examination. The results of the cord blood study showed that two infants having normal red cell osmotic fragility with about 2% Hb E + Hb A + Hb F at birth represented Hb E heterozygosity. Eleven babies had slightly decreased red cell osmotic fragility, a mild degree of microcytosis and poikilocytosis, and hemoglobin types of Hb A + Hb F with no elevation of Hb A2 at birth. They subsequently had hematologic findings consistent with the beta-thal heterozygosity. The means of hematological values of cord blood in the beta-thal trait infants appeared to be statistically different from those in the normal infants only with respect to increased red cell count and reduced MCH. One infant was thought to have the beta-thal trait but had a greater degree of thalassemic changes in red cells; subsequently he turned out to have homozygous beta-thalassemia. Four newborn infants with hypochromia and numerous target cells had 4-7% Hb E + Hb F without Hb A. Follow-up examination showed two cases of Hb E homozygosity; however, the others, who had obvious microcytosis and poikilocytosis in cord blood, finally developed beta-thal/Hb E disease. Thus, a careful study on red cell osmotic fragility, morphology and starch gel electrophoresis at birth allows detection and diagnosis of beta-thal heterozygosity, beta-thal homozygosity, Hb E heterozygosity, Hb E homozygosity and double heterozygosity for beta-thal and Hb E.

Fetal Blood↗
PubMed1988

EF Bart's disease: interaction of the abnormal alpha- and beta-globin genes.

EF Bart's disease is an uncommon form of thalassaemia intermedia resulting from the co-inheritance of alpha-thalassaemia and haemoglobin E in the same subject. Starch-gel electrophoresis revealed two phenotypes in 19 patients with EF Bart's. 16 patients had Hbs CS + E + F + Bart's and the remainder had Hbs E + F + Bart's. DNA mapping and haemoglobin electrophoresis indicated that there are four genotypes, involving 5 abnormal globin genes, responsible for this thalassaemia syndrome.

Adolescent↗
PubMed1988

Alpha-thalassemia in Thailand.

The alpha-thalassemia syndromes are remarkable both for their phenotypic diversity and for their different clinical severity. They are associated with variable degrees of alpha-chain deficits; the clinical manifestations range from asymptomatic cases with normal hematologic findings to the totally lethal Hb Bart's hydrops fetalis syndrome. Recent molecular biology studies have clarified the defects in these alpha-thalassemia syndromes around the world. This paper describes the alpha-thalassemias in Thailand, and covers the types, molecular defects, incidence of each genotype, and their phenotypic expression.

Fetal Blood↗
PubMed1988

The effect of erythroid hyperplasia on iron balance.

Measurements of erythropoiesis and iron balance were made in eight normal and 32 anemic subjects. The latter consisted of 12 individuals with ineffective erythropoiesis (beta-thalassemia/hemoglobin E), 13 subjects with ineffective erythropoiesis and hemolytic anemia (hemoglobin H), and seven subjects with hemolytic anemia (hereditary spherocytosis). A consistent relationship within each group existed between the degree of erythropoiesis and radioiron absorption. Although the effect of erythropoiesis on iron absorption was of similar magnitude in the two thalassemia groups, the effect in hereditary spherocytosis was much less. There was agreement between absorption and ferritin or magnetic susceptibility (SQUID) measurements of iron stores in thalassemia, but in hereditary spherocytosis a discrepancy existed between absorption and ferritin. It is concluded that, although increased erythropoiesis is associated with increased iron absorption, some additional factor associated with red cell breakdown is more directly responsible for the positive iron balance in thalassemia.

Adolescent↗
PubMed1987

Different severity of homozygous beta-thalassemia among siblings.

Different degrees of severity of anemia are presented in three siblings with homozygous beta-thalassemia. II-1, the most severely affected one, is splenectomized and needs frequent blood transfusion, while II-4 has mild anemia and never receives transfusion. II-3 has moderate anemia and mild jaundice and hepatosplenomegaly. Restriction endonuclease DNA mapping revealed the alpha-thalassemia-2 genes in II-3 and II-4 and no alpha-thalassemia-2 haplotype in II-1. Furthermore, II-4, who is mildly affected, is homozygous for alpha-thalassemia-2 whereas II-3 is an alpha-thalassemia-2 heterozygote. These observations indicate that concomitant inheritance of alpha-thalassemia can decrease the severity of beta-thalassemia.

Chromosome Deletion↗
PubMed1987

Viral infections in beta-thalassemia/hemoglobin E patients.

One hundred ten patients with beta-thal/Hb E disease and 60 normal controls matched for age and socioeconomic status were followed for 1.5 years. They were examined clinically, and blood and plasma were studied for Coxsackie B viruses and others. The findings suggest that the patients are more susceptible to Coxsackie B virus but not to rubella, herpes simplex, cytomegalovirus, adenovirus, and M. pneumoniae. In contrast to bacterial infections, splenectomized patients did not show evidence of increased viral infections.

Antibodies, Viral↗
PubMed1987

Different molecular defects of G gamma (A gamma delta beta)o-thalassaemia in Thailand.

DNA from members of 2 Thai families with conditions considered to be delta beta-thalassaemia were studied by using restriction endonuclease DNA mapping. The propositus in family A is a double heterozygote for beta-thalassaemia and delta beta-thalassaemia. DNA analysis reveals a deletion of the beta-globin gene cluster starting at the area between the Sac I and Eco RI sites near the 3' end of the G gamma-gene and extending through the A gamma-, delta- and beta-genes to an unknown extent downstream. In family B, the propositus is delta beta-thalassaemia/Hb E. Deletion of the beta-globin gene cluster begins in the large intervening sequence of the A gamma-gene and removes both delta- and beta-genes downstream.

Chromosome Deletion↗