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

Concentration of iron in plasma, total iron-binding capacity (TIBC), and transferrin saturation are often determined by standard spectrophotometric methods, but iron concentration may be quantified by immunoprecipitation or, electrochemically, by controlled-potential coulometry. Because these iron assays do not all measure the same form(s) of iron, we studied subjects in various states of iron nutriture: normal adults, iron-deficient patients, thalassemia patients with unsaturated transferrin or oversaturated transferrin, and patients with idiopathic hemochromatosis. The spectrophotometric and coulometric methods detected essentially all non-heme iron in plasma; results correlated well but showed a negative bias toward the coulometric method. Results by an immunoprecipitation procedure, which measures only transferrin-bound iron, correlated well with those obtained coulometrically but were slightly higher than the latter. The characteristics of the various methods for iron must be understood by the clinical laboratory if diagnosis of iron disorders is to be accurate.
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PMID:Interpreting results of coulometry and immunoprecipitation in diagnosing iron disorders. 329 21

In 33 patients with thalassemia and idiopathic hemochromatosis, plasma ferritin protein levels ranged from 36 to 5,850 micrograms/L. The iron content of this ferritin as determined by immunoprecipitation ranged from undetectable amounts to 507 micrograms/L. The mean iron content of ferritin protein in those and other subjects with plasma ferritin concentrations of over 1,000 was 6.8% +/- 2.7%. Plasma transferrin was usually saturated with iron in patients with measurable ferritin iron, but exceptions occurred. In studies using electrophoretic separation, it was shown that some ferritin iron moved to transferrin during in vitro incubation, whereas exchange in the opposite direction was extremely limited. Because some plasma ferritin iron was measured by the standard colorimetric plasma iron determination, these observations (a) indicate that plasma ferritin contains a significant amount of iron (b) indicate that a significant proportion of nontransferrin iron in individuals with nontransferrin iron as detected by standard plasma iron and total iron-binding capacity measurements is due to the presence of ferritin, and (c) suggest that large amounts of ferritin iron may affect the saturation of plasma transferrin.
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PMID:Quantitation of ferritin iron in plasma, an explanation for non-transferrin iron. 335 90

Serum vitamin E values are depressed in thalassaemia owing to increased consumption because of the oxidative stress imposed both to red cells and other tissues by haemochromatosis. A study of vitamin E deficiency was carried over a period of about 2 years in 161 transfusion dependent thalassaemic patients aged 4 months to 18 years (including 74 splenectomized subjects) all following the same transfusion and chelation protocol (pretransfusion Hb = 11 gr/dl and daily chelation with subcutaneous infusion of desferrioxamine 12 hr a day). Serum vitamin E levels were determined by Martinek's method. The mean value for the entire series was 0.45 +/- 0.21 mg/dl (normal value 0.76 +/- 0.22), with no differences between splenectomized (0.43 +/- 0.19) and not--splenectomized (0.45 +/- 0.21) subjects. Values of less than 0.32 mg/dl (mean-2SD) were found in 50 patients (31,1%). Below--normal values were noted in 5/11 patients at the time of diagnosis. 124 subjects with less than 0.54 mg/dl received 5-10 mg/Kg/day vitamin E per os. In 38 cases it has been possible to control vitamin E level after one year of therapy. Mean values before treatment were 0.36 +/- 0.13 mg/dl and 1.19 +/- 0.35 mg/dl after therapy. No patient failed to respond and no adverse effect was recorded. These results show that by no means all thalassaemic patients are vitamin E deficient to the point where replacement therapy is necessary, and oral administration can easily correct low serum levels, contrary to what has been found by other workers.
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PMID:[The role of vitamin E in the therapy of thalassemia]. 372 9

Monocyte ferritin (MF) content was measured in normal subjects and patients with a variety of disorders of iron storage. MF was above the normal range in 4 patients with idiopathic haemochromatosis (IHC). However, in 4 patients with transfusion siderosis (TS), secondary to aplastic anaemia, who had similar elevations in serum ferritin, MF was highly elevated. 10 patients with thalassaemia intermedia and thalassaemia major with no previous history of transfusions, but with elevated serum ferritin, also had significantly elevated MF. Disproportionately low MF in IHC could reflect defective ferritin metabolism in reticuloendothelial cells in this disorder. Finally, in 3 patients with acute rises in serum ferritin caused by acute hepatitis, MF was not increased. This suggests that MF is not directly affected by high circulating levels of serum ferritin raised acutely, but rather reflects iron storage status in conditions not associated with primary disorders of iron metabolism.
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PMID:Monocyte ferritin in idiopathic haemochromatosis, thalassaemia and liver disease. 395 67

A controlled trial of continuous chelation therapy in regularly transfused children with homozygous beta-thalassaemia has been in progress at the Hospital for Sick Children since April 1966. In the sixth and seventh years of the trial the effect of this treatment on iron overload has been assessed by estimating serum ferritin levels and liver iron concentrations in both chelator-treated and control groups. When compared with non-chelated controls, results of both these estimations were invariably lower in the chelated group. However, all the results in both groups were very high, and fell within the ranges observed in untreated idiopathic haemochromatosis. A close correlation was found between serum ferritin levels and liver iron concentrations in these children, indicating that serum ferritin is a valuable alternative to liver iron concentration in the assessment of visceral iron overload, even when massive tissue siderosis is present.
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PMID:Serum ferritin in children with thalassaemia regularly transfused. 442 96

The transferrin iron transport system, along with its procurement sites and delivery receptors, provides a highly effective means of satisfying internal iron requirements. Iron uptake by individual tissues is determined by their receptor number, by the relative amounts of monoferric and diferric transferrin in circulation, and by the amount of available iron in donor tissues. Although the modus operandi of this system under basal conditions has been characterized, its exquisite regulation remains an enigma. In some manner, the procurement of iron is determined by iron requirements. What seems to be an inappropriate behavior of the absorptive mechanism in thalassemia and certain other erythroid overload states may actually be life-saving in the absence of transfusion, since it results in higher levels of plasma iron and thereby higher levels of erythropoiesis. The definition of the regulatory mechanism in such conditions may well lead to an understanding of the molecular defect in idiopathic hemochromatosis.
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PMID:Transferrin: physiologic behavior and clinical implications. 608 33

Heterozygous beta thalassaemia with microcytic anaemia (hemoglobin concentration 77 g/l) has been recognized in a 49 year-old woman of Alsatian extraction. A long history of microcytic anaemia had led to inadequate oral iron treatment before the patient was referred to us because of the persisting microcytic anaemia and iron loading. Indeed the patient also had haemosiderosis with a high transferrin saturation (73%) and markedly elevated ferritinaemia (1,114 micrograms/ml). Ferrokinetic data showed increased plasma iron turnover, early transfer of iron to the liver and evidence of ineffective erythropoiesis. She was treated with desferrioxamine (3 g every three days subcutaneously) and serum ferritin levels gradually decreased together with transferrin saturation. After 15 months serum ferritin and transferrin saturation were within the normal range. Several hypotheses are discussed to explain why this patient had haemosiderosis associated with heterozygous beta thalassaemia. The propositus was found to be HLA-A3, which is strongly associated with idiopathic haemochromatosis. Her sister also carries HLA-A3 with heterozygous beta thalassaemia but she has neither anaemia nor iron overload. Thus double heterozygotism is unlikely in our patient.
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PMID:[Iron overload in a beta thalassemia heterozygote of the intermediate type in a subject of Alsation origin. Results of iron chelation treatment]. 633 73

The indications and management of blood transfusion in the haemoglobinopathies have been reviewed. The sickle cell diseases that require transfusion support are sickle cell anaemia, sickle haemoglobin-C and -D diseases and sickle beta-thalassaemia. Homozygous beta-thalassaemia (Cooley's anaemia) is the major problem among the thalassaemias. The pathophysiology of the sickle cell disorders is largely based on the secondary effects of increased blood viscosity, whereas in the thalassaemias the defect is ineffective haematopoiesis. In the former the major problems occur as manifestations of vaso-occlusive crises with disseminated bone and abdominal pain, priapism, stroke and leg ulcers. Bone infarction and aseptic necrosis occur but the widespread bone changes, underdevelopment and haemochromatosis that complicate the thalassaemia are not prominent. Transfusion therapy in the sickle cell diseases is mainly episodic and is guided by the frequency of crises and the severity of vaso-occlusive complications. Partial exchange transfusion and the maintenance of haemoglobin A concentrations at 40 to 50 per cent is frequently indicated. In the thalassaemias, maintenance of haemoglobin levels is essential for normal growth and development. The problem of haemochromatosis is very serious. With hypertransfusion regimens the haemoglobin and haemotocrit are maintained above 12-13 g/dl and 35 per cent. The resulting benefit appears to be reduced blood volume, less iron turnover, and less intestinal iron absorption. The splenomegaly in these disorders is frequently associated with hypersplenism requiring well-timed splenectomy. Chronic and intensive chelation is necessary to prevent the ravages of iron overload. The availability of automated equipment for in vivo and ex vivo blood cell separation has brought new possibilities for improving the management of these haemoglobinopathies. It is feasible, but not as yet practical, to offer transfusions of neocytes (red cells with a mean age of 30 days) which have a 50 per cent longer survival than routine red cell preparations (mean age of 60 days). Neocytes can be prepared ex vivo from fresh routine blood donations using blood cell separator devices. The result is reduced transfusion requirements. A more recent suggestion for using the new technology is to remove the patient's oldest and most abnormal corpuscles on the basis of buoyant density and replacing them with neocytes . Thus the short-lived abnormal red cells would be removed before they could unload their iron. With automation it is possible to perform these procedures on an outpatient basis.
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PMID:Transfusion support for haemoglobinopathies. 637 80

Hemochromatosis is a syndrome which, when fully expressed, is manifested by melanoderma , diabetes mellitus, and liver cirrhosis, with iron overload involving parenchymal and reticuloendothelial cells in many organ systems. This clinical presentation may arise as a consequence of either hereditary or acquired abnormalities of iron overload, although the mechanisms are quite different. In hereditary hemochromatosis (also known as primary, or idiopathic, hemochromatosis), increased intestinal iron absorption leads to excessive accumulations of iron, throughout the body, particularly in parenchymal cells. In secondary forms of iron overload including transfusional hemosiderosis, alcoholic cirrhosis, thalassemia, sideroblastic anemia, and porphyria cutanea tarda, iron accumulates in the reticuloendothelial system initially, but with increasing amounts of total body iron, excessive iron deposits eventually accumulate in parenchymal cells throughout the body producing a picture indistinguishable from hereditary hemochromatosis. In this article, the course, prognosis, and therapy of iron overload will be reviewed in detail. Clinical and experimental data concerning the pathogenesis of the different forms of iron overload will be examined critically. In particular, information relating to possible abnormalities of reticuloendothelial function, intestinal mucosal iron transport, and alterations in serum and tissue isoferritin patterns in hereditary hemochromatosis will be analyzed, and possible directions for future research will be suggested. The mode of inheritance and linkage with the major histocompatibility (HLA) complex will be discussed. Theories on the pathogenesis of tissue damage by excess iron will be evaluated. Methods for measuring the extent of iron overload in clinical practice will be described, including measurements of serum iron, serum ferritin, iron absorption, cobalt excretion, desferrioxamine excretion, liver biopsy and tissue iron determinations, and HLA typing. Finally, unresolved problems in the understanding of the disease process, diagnosis, and therapy will be delineated.
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PMID:Iron overload disorders: natural history, pathogenesis, diagnosis, and therapy. 637 41

Basic ferritin (liver-type) was measured in erythrocytes of subjects with alpha- and beta-thalassemia trait, thalassemia intermedia and Cooley's disease, and compared with normals and patients with abnormal iron metabolism without erythrocyte metabolic defect (iron deficiency anemia and idiopathic hemochromatosis). In all the thalassemic syndromes considered, erythrocyte ferritin was significantly higher than in normals (p less than 0.001) and increased progressively with the increasing 'severity' of the thalassemic disorder. In both thalassemic and non-thalassemic subjects, erythrocyte ferritin levels were related to body iron status, but in the thalassemic group, the increased erythrocyte ferritin values seemed also to be closely related to the intracellular metabolic abnormality. The severity of the defect in globin chain synthesis seemed to play an important role in determining ferritin accumulation in red cells of thalassemic subjects.
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PMID:Erythrocyte ferritin in thalassemia syndromes. 642 38


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