Search PubMed⌕ Search

Biomedical subjects

P Wasi

Publications and source records attributed to P Wasi.

At least 73 records · Page 4Linked to original sources
PubMed1986

Comparison of erythrocyte antioxidative enzyme activities between two types of haemoglobin H disease.

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.

Catalase↗
PubMed1986

Increased phagocytosis of Plasmodium falciparum-infected erythrocytes with haemoglobin E by peripheral blood monocytes.

Erythrocytes from subjects with homozygous and heterozygous haemoglobin E (HbE) infected with Plasmodium falciparum in vitro were phagocytosed to a greater extent by normal human monocytes than infected erythrocytes from normal subjects. Susceptibility to phagocytosis was maximal when the parasites developed to trophozoite and schizont stages in both normal and patients' erythrocytes. The increased susceptibility of P. falciparum-infected HbE erythrocytes to phagocytosis by monocytes may play a role in protection against malaria.

Cells, Cultured↗
PubMed1985

Concomitant inheritance of alpha-thalassemia in beta 0- thalassemia/Hb E disease.

Concomitant inheritance of alpha-thalassemia in patients with beta 0-thalassemia/hemoglobin (Hb) E disease was detected by restriction endonuclease DNA mapping. Among 42 patients with beta 0-thalassemia/Hb E disease, seven were found to have an alpha-thalassemia-2 haplotype. Of these, five belonged to the rightward or 3.7-kb type of alpha-thalassemia-2 and the remaining two the leftward or 4.2-kb type. All the seven patients with alpha-thalassemia-2 haplotype had hemoglobin levels of 7.4 g/dl or above; those without detectable alpha-thalassemia had hemoglobin levels both higher and lower than 7.4 g/dl. The latter attended the clinic regularly, the former did occasionally. These findings suggest that concomitant inheritance of alpha-thalassemia can alleviate the severity of beta 0-thalassemia/Hb E disease. Failure to find alpha-thalassemia-1 haplotype in these patients suggests that concomitant inheritance of alpha-thalassemia-1 with beta 0-thalassemia/Hb E might lead to so mild a condition that the individuals do not present clinically. The fact that many patients without a detectable alpha-thalassemia haplotype also had hemoglobin levels of 7.4 g/dl or higher suggests that there are additional factors responsible for the mildness of beta 0-thalassemia/Hb E disease.

Adolescent↗
PubMed1985

Quantitative changes of red blood cell shapes in relation to clinical features in beta-thalassemia/HbE disease.

Quantitative analysis of red blood cell (RBC) shapes was performed in 79 patients with beta-thalassemia/HbE disease, using scanning electron microscopy (SEM). Most patients had many abnormal RBC shapes, namely: torocytes, codocytes, dacryocytes, keratocytes, and schizocytes with a reduction in the number of normally shaped red blood cells (discocytes). Splenectomy, larger splenic sizes, and increasing anemia all were associated with a further reduction in the number of discocytes, reflecting increasing numbers of abnormally shaped RBC. The number of torocytes was increased with anemia; a larger spleen was associated with a decrease and splenectomy with an increase in the number of torocytes, indicating that they are destroyed by the spleen. The numbers of codocytes and echinocytes were singularly associated with splenectomy. Most likely, almost all of the echinocytes are destroyed by the spleen. The red blood cell types that occur as a result of RBC fragmentation, namely, dacryocytes, keratocytes, and schizocytes, were remarkably associated with the splenic status; larger splenic size was associated with an increased number of these cells, while splenectomy was associated with a noticeable reduction in their numbers. This finding confirms the role of the spleen in the fragmentation of thalassemic RBC. An increasing degree of anemia did not affect the number of codocytes and echinocytes, but was associated with a mild increase in the number of fragmented RBC and a significant increase in the number of torocytes.

Erythrocyte Count↗
PubMed1985

The morphology of redox-dye-treated HbH-containing red cells: differences between cells treated with brilliant cresyl blue, methylene blue and new methylene blue.

The ultrastructure of redox-dye-treated HbH-containing red cells has been shown to be dependent on the nature of the redox dye used. Brilliant cresyl blue causes the formation of a large number of small inclusions which are invariably attached to the inner surface of the red cell membrane. Methylene blue and new methylene blue cause the formation of a much smaller number of larger inclusions only some of which appear to be membrane-bound. These ultrastructural differences are reflected in marked differences in the light microscope appearances of the supravitally-stained cells.

Adult↗
PubMed1985

Thalassemia in southeast Asia: determination of different degrees of severity of anemia in thalassemia.

beta (0)-Thalassemia/Hb E in Southeast Asia varies greatly in severity, with hemoglobin levels ranging from 2.5 to 13.5 g/dl, averaging 7.7 g/dl. Results of systematic investigations to find out what determines different levels of severity are reviewed. Concomitant inheritance of alpha-thalassemia significantly decreases the severity. Different degrees of severity in the majority of cases, however, is not due to alpha-thalassemia. Concordance of hemoglobin levels among patients who are sibs prevails, suggesting polygenic factor determinants. Potential factors ruled out as determinants for different levels of severity are discriminating fetal hemoglobin production, erythrocyte superoxide dismutase activity, reticulo-endothelial function, and failure of erythropoiesis compensation. Red cell survival and globin synthesis studies indicate that different degrees of excess of alpha-chains leading to different red cell pathology and survival are responsible for variable severity. Degrees of excess of alpha-chains in this circumstance are probably mainly determined by erythrocyte proteolytic activity. The relationship between the hemoglobin levels and erythrocyte cytosol proteolytic activity in 15 beta(0) -thalassemia/Hb E disease patients in whom a deletional type of alpha-thalassemia had been ruled out by DNA mapping is striking, with a correlation coefficient of 0.78. This finding suggests that modulation of erythrocyte proteolysis is another approach for treatment of thalassemia.

Asia, Southeastern↗
PubMed1984

Determination for different severity of anemia in thalassemia: concordance and discordance among sib pairs.

The degree of anemia in beta(0)-thalassemia/hemoglobin E disease is highly variable. As part of an attempt to identify determinants of this variability of severity we studied concordance and discordance of hemoglobin levels among sib pairs. The distribution of differences of hemoglobin levels in 216 sib pairs from 98 families showed a remarkable skewness toward the lower values with a mode at 0-0.5 gm/dl. The prevailing concordance of hemoglobin levels in patients from the same families and the persistence of the patterns indicate that polygenic factors are mainly responsible for the variability of anemia in this disease.

Female↗
PubMed1984

The molecular basis of alpha-thalassaemia in Thailand.

The molecular basis of alpha-thalassaemia has been established in 48 Thai subjects with Hb H disease and 15 with the Hb Bart's hydrops fetalis syndrome. This study has shown that in this population there are at least 18 different types of chromosome carrying seven independent alpha-thalassaemia mutations one of which is a novel deletion removing the entire alpha-globin gene complex. Although there are a limited number of alpha-thalassaemia determinants in the Thai population, there is a remarkable degree of variation in the genetic markers which flank them. These markers may be of value in establishing the evolutionary history of the alpha-thalassaemias.

Chromosome Deletion↗
PubMed1984

Increased red blood cell protoporphyrin in thalassemia: a result of relative iron deficiency.

Erythrocyte protoporphyrin (EP) was measured in 50 normal control subjects, 22 iron-responsive anemic subjects, and in 106 patients with thalassemic diseases. All normal subjects had EP of less than 80 micrograms/dL red blood cells, whereas all iron-deficiency subjects had EP of more than 80 micrograms/dL red blood cells. Six of 22 heterozygotes for thalassemias had elevated EP, and all of these had transferrin iron saturation of less than 16%, reflecting a complicating iron deficiency. Among 52 patients with beta-thalassemia/hemoglobin (Hb) E disease, 26.9% had elevated EP levels, and among 32 patients with Hb H disease, 40.6% had elevated EP. These elevated EP levels were associated with transferrin iron saturation between 18 and 44%. In none of the thalassemic patients with transferrin iron saturation above 44% was EP elevated. These findings suggest that elevation of EP in some thalassemic patients causally is related to iron supply inadequate for the massively expanded erythropoiesis. This relative iron deficiency in thalassemia occurs at a transferrin iron saturation level usually considered to be normal. These relationships demonstrate the need for an increased iron supply in patients with erythroid marrow hyperplasia, if erythropoiesis is to proceed at maximal rates.

Adult↗
PubMed1984

Ultrastructure and cell cycle distribution of erythropoietic cells in heterozygotes and homozygotes for haemoglobin E.

Marrow aspirates from heterozygotes and homozygotes for haemoglobin E (HbE) have been studied by electron microscopy and by the technique of combined Feulgen microspectrophotometry and 3H-thymidine autoradiography. The erythropoietic cells of heterozygotes did not contain any precipitated globin chains and the proliferating erythroblasts of such individuals showed no abnormality in their distribution in the different stages of interphase. By contrast, 0-1.5% of late erythroblast profiles and 3.1-12.8% of marrow reticulocyte profiles of homozygotes contained intracellular inclusions resembling precipitated alpha-chains. Although precipitated globin chains were not seen in the early polychromatic erythroblasts of homozygotes, the number of these cells in the G2 phase relative to that in the S phase was increased. These data indicate that there is probably little or no imbalance of globin chain synthesis in heterozygotes, a substantial degree of imbalance in homozygotes, and a disturbance of erythroblast proliferation in homozygotes which cannot be attributed to the deleterious effects of detectable intracellular alpha-chain precipitates. The electron microscope and cell cycle distribution data in the homozygotes for HbE were similar to those in two heterozygotes for beta thalassaemia.

Bone Marrow↗
PubMed1984

The fate of excess beta-globin chains within erythropoietic cells in alpha-thalassaemia 2 trait, alpha-thalassaemia 1 trait, haemoglobin H disease and haemoglobin Q-H disease: an electron microscope study.

Electron microscope studies have been performed on bone marrow cells from individuals with various alpha-thalassaemia syndromes. Globin chain precipitates were rarely found in the erythropoietic cells of a subject with alpha-thalassaemia 2 trait. By contrast, such precipitates were found in 0.6 - 1.3% of the erythroblast and marrow reticulocyte profiles in two cases of alpha-thalassaemia 1 trait, 2.1 - 13.7% of profiles in five patients with haemoglobin H (HbH) disease and 6.2% of profiles in one patient with haemoglobin Q-H (HbQ-H) disease. In the patient with HbQ-H disease, but not in the others, the nuclei of some erythroblasts displayed the 'Swiss cheese' appearance which has been reported in some forms of congenital dyserythropoietic anaemia. It is proposed that in alpha-thalassaemia 2 trait, where the degree of excess of beta-chains is slight, most of the excess chains are degraded by proteolysis. In alpha-thalassaemia 1 trait, where there is a greater excess of beta-chains, the excess chains can undergo either proteolysis or precipitation, but there is little or no tetramerization to form soluble HbH. Finally, in HbH disease, where the degree of excess is considerable, the excess beta-chains may be subject to proteolysis, precipitation and tetramerization.

Adult↗
PubMed1984

Non-transferrin plasma iron in beta-thalassaemia/Hb E and haemoglobin H diseases.

Non-transferrin plasma iron concentrations were determined in 45 normal controls and in 37 patients with Hb H disease and 104 patients with beta-thalassaemia/Hb E disease. This revealed that non-transferrin plasma iron exists in cases with severe iron overload, more striking in beta-thalassaemia/Hb E than in Hb H disease. Non-transferrin plasma iron is associated with higher transferrin iron saturation and higher plasma ferritin levels. The most striking finding was the significantly higher non-transferrin plasma iron in splenectomized patients with beta-thalassaemia/Hb E disease than in the non-splenectomized patients. In view of the potential toxicity of non-transferrin iron, this fraction of iron may be responsible for tissue damage in these patients especially after splenectomy.

Hemoglobin E↗
PubMed1984

Hematologic and biosynthetic studies in homozygous hemoglobin Constant Spring.

The elongated alpha-globin chains of hemoglobin Constant Spring (alpha cs chain of HbCS ) are produced in low amounts such that the alpha cs-gene acts as a form of alpha-thalassemia; yet in the homozygous state the pathophysiological effects of this mutant are more severe than in the corresponding conditions that result from alpha-globin gene deletions. In studies designed to examine this discrepancy, we have demonstrated that a significant proportion of red cells produced in an HbCS homozygote has a much reduced red cell life span. Contrary to previous reports, we have been able to demonstrate the expected deficit in alpha-chain production in this condition and have shown that both the cessation of globin chain synthesis in vitro and the destruction of the excess beta-chains occur unusually rapidly. Comparison with various deletion forms of alpha-thalassemia suggests that, in terms of intracellular globin chain precipitates and free beta-chain pool, homozygous HbCS red cells more closely resemble those of HbH disease, with three of the four alpha-genes inactivated, than they do the more comparable alpha-thalassemia carriers with only two genes deleted.

Adult↗
PubMed1984

Cardiac pathology in 47 patients with beta thalassaemia/haemoglobin E.

Autopsy protocols and heart slides of 47 patients with beta thalassaemia/haemoglobin E disease were reviewed. All but 1 patient had cardiac hypertrophy, accompanied by dilatation in 17; 5 of 9 patients (56%) with right ventricular and 11 of 22 patients (50%) with biventricular hypertrophy had chronic pulmonary thromboembolism. Cardiac iron deposition while present in 15 patients (32%) was very slight, in contrast to the amount of iron in their liver and pancreas. Four patients had fibrinous pericarditis, 2 with rheumatic heart disease. Twelve patients had chronic pericardial changes, 7 with adhesive pericarditis. The effects of cardiac pathology on the morbidity and mortality of patients with beta thalassaemia/haemoglobin E disease were discussed.

Adolescent↗
PubMed1983

Increased erythrocyte superoxide dismutase activities in beta 0-thalassaemia/haemoglobin E and in haemoglobin H diseases.

Erythrocyte superoxide dismutase activities were measured in 45 subjects, 15 each of beta 0-thalassaemia/haemoglobin (Hb) E disease, Hb H disease, and normal. The erythrocyte superoxide dismutase activities were significantly higher in the patients with beta 0-thalassaemia/Hb E and Hb H diseases than in the normal subjects. The increase of erythrocyte superoxide dismutase activities is most likely due to abnormalities specific to thalassaemic red cells rather than an increased number of younger red cells for reticulocytes and nucleated red blood cells did not affect the enzyme activity. Patients with beta 0-thalassaemia/Hb E disease with lower haemoglobin concentration had significantly higher superoxide dismutase activities. In all 45 subjects haemoglobin concentrations and superoxide dismutase activities were inversely correlated (r = -0.60 (p less than 0.001)). This indicates that the amounts of superoxide generated in the red cells may, at least partly, determine severity of red cell damage and thus severity of disease; the increased superoxide dismutase activity in thalassaemia is a response to superoxide generated in greater amounts because of accumulation of excessive globin chains and iron in the red cells. The superoxide dismutase activities in Hb H disease, an alpha-thalassaemic disease, were found to be strikingly increased, higher than in beta 0-thalassaemic disease or other conditions.

Anemia, Hemolytic, Autoimmune↗
PubMed1983

Iron absorption in patients with beta-thalassaemia/haemoglobin E disease and the effect of splenectomy.

Intestinal 59Fe absorption was measured in 16 patients with beta-thalassaemia/haemoglobin E disease and in 5 normal controls, using a total-body counting technique. The average iron absorption in the patients was 62% in contrast to 16.5% in the normal controls. 6 of the 9 splenectomized patients had absorption values above 65%, while only 2 of the 7 nonsplenectomized patients had comparably high values.

Adult↗