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

At present the treatment of thalassaemia major consists of regular blood transfusions coupled with chelation therapy using deferoxamine. A complementary approach to the problem is the use of blood units enriched with young red cells (neocytes), which reduce the transfusional frequency and thereby diminish the risk of iron overload. Young red cell units were collected from blood from 60 volunteer donors using a cell separator (IBM 2997). Donors' blood was anticoagulated and the young red cell harvesting carried out over 4 h at a constant rotor speed of 500 rpm. Three biological criteria were used to evaluate young red cell quality: the number of reticulocytes, the pyruvate kinase activity and the mean corpuscular volume, all of which show an enrichment of young red cells as compared to standard donor units. The 51Cr young red cell survival in four normal donors and in two splenectomized patients showed an increased red cell half-life compared to the same study performed with standard blood units. Blood consumption was diminished significantly when the two patients were transfused with young red cell units. It must be emphasized that, despite the high cost of this blood product, the efficiency of this transfusion technique, by reducing blood consumption, represents important progress and a hopeful treatment for chronic anaemia.
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PMID:Neocytopheresis: a new approach for the transfusion of patients with thalassaemia major. 373 11

In patients with iron overload associated with severe, transfusion-dependent beta-thalassemia, congestive heart failure develops during the second decade of life. Biventricular heart function was studied by multigated radionuclide angiography in 22 patients with beta-thalassemia major. Six patients were symptomatic. Congestive heart failure developed in five patients at the time of blood transfusions, and one other patient had been treated for multiple ventricular extrasystole. The mean (+/- SD) left ventricular ejection fraction was normal (63.0% +/- 7.6%). Only one patient had a left ventricular ejection fraction under the normal level (less than 50%). The mean (+/- SD) right ventricular fraction (RVEF) was 33.3% +/- 9.4%. In only three patients was the RVEF normal (greater than or equal to 40%); an RVEF under 30% was registered in six patients. We suggest that the early right ventricular dysfunction in patients with beta-thalassemia may be due to pulmonary hypertension secondary to iron overload and iron deposits in the ventricles.
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PMID:Right ventricular cardiac dysfunction in beta-thalassemia major. 378 90

The relative proportions of T-cell (OKT3-positive, OKT4-positive and OKT8-positive) and B-cell (SIg-positive) populations in peripheral blood obtained from 29 chronically transfused patients with beta-thalassaemia major were compared with those of 17 healthy controls. Changes attributable to blood transfusion and/or splenectomy are described. The percentage of OKT8-positive (T-suppressor) cells found in the thalassaemic patients increased linearly (P less than 0.001) with the number of units transfused, irrespective of splenectomy. The percentage of OKT4-positive (T-helper) cells varied inversely with increasing transfusion in nonsplenectomized patients while in those who were splenectomized no significant correlation was apparent. Thus, in both groups of patients the T4/T8 ratio declined in a transfusion-related manner. The splenectomized patients experienced a marked and persistent lymphocytosis due to an increase in the number of both T- and B-cells. When the results were expressed as percentages, the greatest increase occurred in the number of B-cells, this increase being unrelated to the number of transfusions received. None of the serum parameters usually associated with iron overload or abnormal liver function correlated with the observed increases in T-suppressor and SIg-positive cells. These findings corroborate reports that transfusion of blood products may lead to decreased T4/T8 ratios. However, none of the patients studied manifested clinical signs of acquired immune deficiency syndrome (AIDS). Accordingly, studies which define transfusion related AIDS on the basis of analyses with monoclonal antibodies must be viewed with caution.
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PMID:Disproportionate lymphoid cell subsets in thalassaemia major: the relative contributions of transfusion and splenectomy. 387 79

We have characterized HLA antigens in subjects with beta-thalassaemia trait with and without iron overload. 50% of the cases with iron overload (v 18% of those without iron overload, P less than 0.01) are carriers of HLA-A3, the HLA antigen tightly linked to the IH allele. Thus, in a considerable number of these subjects, beta-thalassaemia and IH coexist. This association exerts a synergistic effect in inducing iron overload.
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PMID:Iron overload in subjects with beta-thalassaemia trait: role of idiopathic haemochromatosis gene. 387 23

Insulin and glucagon secretion were studied during an oral glucose tolerance test and arginine infusion in 11 patients with thalassaemia intermedia, who showed laboratory evidence of iron overload. Mean blood glucose concentrations in patients with thalassaemia intermedia were significantly higher than normal and 3 of 11 patients had impaired glucose tolerance. The principal abnormality appears to be a deficiency in insulin and glucagon from the pancreas in response to oral glucose tolerance and arginine stimulation tests. Several factors, such as iron overload, chronic hypoxia, zinc deficiency and increased catecholamine production secondary to anaemia, might play a part in the pathogenesis of these abnormalities. Each of these factors affect individual cases to a varied degree. Our data emphasize the mildness of carbohydrate defect as compared to the degree of insulinopenia and indicate the necessity for prescribing measures which prevent excessive iron deposition and improve iron excretion in thalassaemic patients with iron overload.
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PMID:Alpha and beta cell evaluation in patients with thalassaemia intermedia and iron overload. 390 15

High Hb level transfusion scheme for treatment of thalassemia mayor has improved life prognosis but has increased also the incidence of Diabetes Mellitus. 10 patients with thalassemia major have been followed with OGTT for a period 4 years long (1979-1982). In 1979 we changed from low to high level transfusion regimen, and we began to use the pump for slow subcutaneous administration of desferrioxamine to treat iron overload. The results we obtained show a progressive increase of the average values in the insulinemic and glycemic plasma concentration from year to year. At the beginning of the follow-up period, insulinemic and glycemic values after OGTT showed a primitive pancreatic damage which evolved towards a better pancreatic function with the appearance of a peripheral insulin resistance. It is probable that both chronic hypoxia (low Hb level) and the iron overload (high Hb level) may cause, with different processes, an impairment of glucose metabolism.
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PMID:[Beta-pancreatic function in subjects with thalassemia. A 4-year follow-up]. 391 49

Serum ferritin, an index of iron stores, was studied in 60 patients with porphyria cutanea tarda (PCT), in 21 patients who had other liver diseases without siderosis (cirrhosis [LC] and chronic active hepatitis [CAH]), and in 32 patients with associated liver siderosis (alcoholic LC, LC and CAH in minor thalassemia). Ferritin levels were higher in patients with porphyria than in healthy controls and patients without liver siderosis (P less than 0.001), whereas no statistical difference was observed between patients with porphyria and those with liver siderosis. Because iron removal is considered the treatment of choice for PCT, some patients with PCT underwent phlebotomy and others received chelating therapy with subcutaneous infusion of deferoxamine. Follow-up of the patients showed a correlation between serum ferritin level and urinary porphyrin excretion; when the clinical and biochemical syndrome became normal, serum iron and ferritin had fallen to normal values (t test pair data analysis before and after: P less than 0.001 in each group). No appreciable difference was found between controls and patients with PCT whose conditions had been normalized, irrespective of the chronic liver damage always present in PCT. Our results suggest that serum ferritin increase in PCT is related more to liver iron overload than to liver damage, and ferritin follow-up is recommended to indicate the exhaustion of hepatic iron stores during iron depletion therapy, as well as to detect an early replenishment after remission.
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PMID:Serum ferritin in the assessment of liver iron overload and iron removal therapy in porphyria cutanea tarda. 394 Dec 93

A group of heteroaromatic chelators with an alpha-ketohydroxy binding site have been tested for their ability to mobilise iron from transferrin in vitro. When these chelators were mixed with iron-saturated transferrin at physiological pH, biphasic reactions were observed. The alpha-ketohydroxy heteroaromatic chelators were found to cause substantial iron removal compared to other known chelators. These findings suggest that these chelators may have an important role in the study of iron metabolism and a possible clinical use in the treatment of transfusional iron overload in thalassaemia, and other diseases of iron imbalance.
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PMID:The study of iron mobilisation from transferrin using alpha-ketohydroxy heteroaromatic chelators. 394 57

A series of polymers bearing hydroxamic acid-terminated side chains were prepared for the purpose of developing new iron chelators for treating iron overload in beta-thalassemia (Cooley's anemia) and other iron diseases. The polymers are for the most part amino acid amide derivatives of acrylic and methacrylic acid with the terminal carboxyl group converted to the hydroxamic acid. The polymers are generally water soluble and sequester iron(III) avidly. The polymeric iron chelators were assayed via a mouse screen for activity in removing iron. Iron overloaded mice were administered i.p. the iron chelator over a 7-day period. Urine and feces were collected and the iron content measured by atomic absorption. At the end of the treatment period the mice were sacrificed and the livers and spleens were homogenized and examined for iron content. The results were compared with similar data obtained for the iron chelator drug desferrioxamine as a standard. Four of the polymers prepared exhibited strong activity, as good or better than desferrioxamine in iron removal capability. The four polymers are the polyacroloyl and polymethacryloyl derivatives of beta-alanine with the side chain carboxyls converted to the N'--H or N'--CH3 hydroxamic acids. Of these four the polyacryloyl N'--CH3 derivative exhibited superior behavior, being 3 to 5 times as effective as desferrioxamine at the lower dose level. None of the four polymers produced toxic signs and the administration was accompanied by little or no pain response.
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PMID:Evaluation of polymeric hydroxamic acid iron chelators for treatment of iron overload. 397 22

The systolic and diastolic left ventricular (LV) function was studied by M-mode echocardiography in 60 patients with beta-thalassemia (mean age +/- SD, 17.1 +/- 7.5 years) and 30 healthy controls (15.4 +/- 3.8 years). In thalassemic patients, echocardiograms were obtained 48 h posttransfusion, with a mean hemoglobin level of 12.4 +/- 0.9 g/dl. To examination time, thalassemic patients had received 30-774 blood units (318 +/- 176). Congestive heart failure (CHF) was present in 14 thalassemic patients (19.6 +/- 3.4 years), while 46 (16.3 +/- 8.2 years) had no clinical signs of CHF. Global LV function study showed enlarged LV dimensions in thalassemic patients with CHF (p less than 0.001) and similar cavity size in controls and patients without CHF (p = NS). The same was true for velocity measurements, while diastolic LV indices had similar values in all groups (p = NS). Segmental LV function study showed no significant differences in systolic and diastolic LV posterior wall behavior between thalassemic patients and controls, and even more, between thalassemic patients with and without CHF, while it was independent of iron load. These findings indicate that global and segmental LV function in thalassemic patients remain within normal limits until the final stages of the disease. CHF onset marks the deterioration of LV systolic performance, while global and segmental diastolic indices do not change significantly. The above findings question the role of iron overload in the development of CHF in beta-thalassemia.
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PMID:Global and segmental left ventricular function in beta-thalassemia. 399 17


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