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)

Normal red blood cells, preincubated for 75 min with 1.15 mM menadione sodium bisulfite lose potassium and water on subsequent incubation at 37 degrees C for 24 h without menadione. The potassium loss is increased by addition of calcium and prevented by addition of glucose. Since normal red cells treated with menadione behave like untreated hypochromic cells, both from beta-thalassaemia or iron deficiency anaemia in respect to membrane permeability to potassium, it may be supposed that menadione induces in normal red cells an abnormality similar to that naturally occurring in hypochromic cells.
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PMID:Increased potassium permeability induced in vitro by menadione in normal human red cells. 84 Dec 69

Patients with severe thalassaemia major suffer endocrine and other abnormalities before their eventual death from iron overload due to repeated blood transfusions. The endocrine status of 31 thalassaemic patients aged 2-5 to 23 years was investigated. Exact data were available on the rate and duration of blood transfusion in all of them and in many the liver iron concentration was also known. Although the patients were euthyroid, the mean serum thyroxine level was significantly lower, and the mean thyrotrophic hormone level significantly higher, compared with the values found in normal children. Forty oral glucose tolerance tests with simultaneous insulin levels were performed in 19 children, of whom 5 developed symptomatic diabetes and one had impaired tolerance. Previous tests on all 6 patients were available and some showed raised insulin levels possibly due to insulin resistance. 2 patients had clinical hypoparathyroidism and are described. The parathyroid hormone levels determined by radioimmunoassay in 25 patients were below the mean for the age group in all and outside the reference range in 16. Nonfasting plasma calcium levels were not reduced. Puberty was delayed in some patients. Concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) measured in urine from 7 girls and 5 boys showed considerable variation. In the boys there was an overall tendency for FSH and LH excretion to be low with regard to age, but with respect to puberty rating FSH exretions were normal or low and LH normal or raised. The girls showed a tendency for LH but not FSH excretion to be raised in relation to puberty rating. The severity of the endocrine changes was related to the degree of iron loading and is discussed in relation to previous work in which the iron loading has rarely been accurately indicated nor parathyroid status assessed.
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PMID:Hormonal changes in thalassaemia major. 100 88

2-3-Dihydroxybenzoic acid was evaluated as a potentially useful, orally effective iron-chelating drug by performing iron balance studies in patients with beta-thalassaemia major. The administration of this substance at 25 mg/kg/d to five patients for 8 d caused an average increase in iron excretion of 4.5 mg/d. When the drug was administered at 25 mg/kg q.i.d. to eight patients for 21 d, iron excretion increased to 6.5 mg/d. Chelation was highly specific for iron with changes in magnesium and calcium excretion being insignificant. The drug was well tolerated with side effects limited to gastrointestinal complaints which ameliorated when the drug was taken with food. These studies provide a rationale for further evaluation of 2,3-dihydroxybenzoic acid in patients with iron overload.
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PMID:Chelation studies with 2,3-dihydroxybenzoic acid in patients with beta-thalassaemia major. 100 20

The study of calcium metabolism in ten thalassaemic children comperatively with controls after oral administration of 47Ca has shown diminished intestinal absorption. It is suggested that this finding is propably related in part with the pathogenesis of the osteoporosis in thalassaemia.
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PMID:Calcium metabolism in children suffering from homozygous beta-thalassaemia after oral administration of 47Ca. 127 16

Renal function studies were performed in 41 patients with sickle cell-beta thalassaemia (S/b thal) and compared to 14 normal controls and 8 sickle cell (SS) patients. Polyuria, hyposthenuria and mild proteinuria were common in both S/b thal and SS patients. A renal concentrating defect was manifest in all patients studied, and in 4 of the 7 S/b that patients tested, an abnormal acidification test was found. A statistically significant negative correlation (n = 19, r = -0.48, p less than 0.05) was noted between creatinine clearance (CCr) and age for the patients over 30 years. There was no correlation between hemoglobin and CCr; on the contrary, a statistically significant negative correlation was found between CCr and hemoglobin F (n = 29, r = -0.428, p less than 0.05) Our S/b thal and SS patients showed a decreased daily excretion of sodium, calcium, phosphate and magnesium and lower serum magnesium levels than the controls. One third of the S/b thal patients showed hyperuricosuria, and a statistically significant negative correlation was noted between serum uric acid and its fractional excretion in all S/b thal patients (n = 41, r = -0.450, p less than 0.01). Serum phosphate levels were independent of age. A statistically significant positive correlation was found between the tubular reabsorptive capacity for phosphate and the number of painful crises per year (n = 33, r = 0.836, p less than 0.001). We conclude that renal involvement in the double heterozygous state is as severe as in homozygous sickle cell disease.
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PMID:Renal involvement in sickle cell-beta thalassemia. 138 36

Regular bone survey radiographs have allowed identification of limb deformity and metaphyseal changes in several patients with thalassaemia major treated at the Adelaide Children's Hospital. Following the progression of limb deformity in five of these patients who were receiving human growth hormone therapy, the records of 25 thalassaemia patients were reviewed. Six patients had evidence of limb deformity, four of whom also had metaphyseal changes. Three additional patients had metaphyseal changes alone. Patients with either type of skeletal change shared similar characteristics, including younger age, earlier commencement of desferrioxamine therapy, better compliance and, in general, lower levels of ferritin. Females predominated in both groups. The frequency of sensorineural hearing loss was similar in affected and nonaffected groups and biochemical parameters, especially plasma calcium, phosphate, alkaline phosphatase, and zinc, which were normal in all patients. The cause of these skeletal changes is not clear; however, several potential factors need to be considered. Among these are focal marrow expansion in the metaphyseal region due to incomplete suppression of erythropoiesis and possible effects of desferrioxamine, including direct interference with bone growth, altered response of bone to inflammation or infection, and altered bone metabolism related to chelation of trace metals. While we can only speculate on aetiological factors, it is clear that human growth hormone therapy has resulted in exaggeration of deformity due to an increased rate of bone growth or decreased rate of mineralization of physeal cartilage. We believe that bone survey radiographs are useful in early identification of skeletal changes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Limb deformity and metaphyseal abnormalities in thalassaemia major. 774 45

In human red cells, Ca is mainly bound to the inner side of the plasma membrane. A smaller part may be present within intracellular Ca storing vesicles, while only a few percent of total red cell Ca is in ionized form. In some hemolytic anemias (sickle cell anemia, beta-thalassemia), an increased number of endocytotic vesicles storing Ca is probably responsible for the elevation of total red cell Ca content. Red cell Ca inward transport, which is partially susceptible to inhibition by Ca entry blockers, has been reported to be enhanced by physiological shear stress and enrichment in membrane cholesterol, as well as in some hemolytic anemias. Normal intracellular ionized Ca levels have been assessed in several diseases where elevated Ca inward transport rates or decreased Ca efflux through the Ca pump (hemolytic anemias, cystic fibrosis, essential hypertension) had been observed previously. Thus, red cell Ca homeostasis is apparently capable of keeping ionized Ca levels within the physiological range of 20-60 nM under most pathological conditions investigated so far. Conceptually, changes in red cell Ca homeostasis (or also in other red cell membrane parameters) may be of pathophysiological importance in two respects: 1) A disturbance may be directly responsible for some of the symptoms associated with a disease. This is the case in sickle cell anemia, where red cell dehydration is possibly caused by transient elevations of intracellular ionized calcium, which may activate K efflux through the Ca-activated K channel. The presence of dehydrated red cells will, in turn, lead to microvascular occlusion, a pathophysiologically important phenomenon in sickle cell anemia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Calcium homeostasis of human erythrocytes and its pathophysiological implications. 164 22

Beta-thalassemia/Hb E is a genetic disease prevalent in Thailand. This study has used atomic absorption spectroscopy to evaluate red cell and plasma calcium, copper and zinc in patients with beta-thalassemia/Hb E, both splenectomized and non-splenectomized. The levels of these trace elements in both red cells and plasma were different between the non-thalassemic controls and the disease patients. The most prominent result was that calcium concentration in red cells increased significantly in thalassemia subjects, particularly in splenectomized cases. These results might reflect the abnormal trace element metabolism and defects in the calcium transport system of the red cell membrane in thalassemia.
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PMID:Red cell and plasma calcium, copper and zinc in beta-thalassemia/hemoglobin E. 194 75

Four female patients with thalassemia intermedia developed secondary acetabular protrusion. These cases could be the first reported cases of nontraumatic acetabular protrusion in patients with thalassemia. The rarified pelvic bone may be due to medullary hyperplasia, iron overload, or disordered calcium metabolism in conjunction with osteomalacia. The fact that currently patients with beta-thalassemia have a longer life expectancy may explain the recent observation of this entity, which should become more familiar to orthopedic surgeons who treat thalassemia patients in the future.
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PMID:Acetabular protrusion in thalassemia. A report of four cases. 232 31

Regular subcutaneous desferrioxamine therapy has prolonged the life and reduced the incidence of cardiac, endocrine and liver complications of iron overload in patients with thalassaemia major and other refractory transfusion-dependent anaemias. Its full impact will be apparent only when patients who began this treatment as children 10 years ago reach adult life. The major problems with s.c. DF therapy are its cost and the difficulty of patient compliance with a painful and cumbersome method of administration. Attempts to maintain normal iron stores in these patients has resulted in significant toxicity caused by the excessive use of DF. Although recent studies have shown that long-term subcutaneous calcium diethylene triamine penta-acetic acid (Ca-DTPA) can be used as an effective alternative to s.c. DF (Wonke et al, 1988), this treatment presents additional potential problems of zinc depletion which can be prevented only by careful management. The prospects of an inexpensive, orally active iron chelator are now real (Kontoghiorghes and Hoffbrand, 1988) and it is to be hoped that long-term results at least as good as those with s.c. DF will be achievable. Such oral chelators may be available to a far wider group of patients, than s.c. DF, and the problems of cost and compliance may be diminished.
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PMID:Results of long-term subcutaneous desferrioxamine therapy. 266 Sep 32


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