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)

Eight patients with beta-thalassemia who were given long-term treatment with combined multiple transfusions and chelation therapy underwent adrenal testing. The six male and two female patients ranged in age from 7 to 19 years. Six of eight patients had delayed bone ages and height greater than 2.5 SDs below the mean. Of the six patients more than 13 years of age, two had clinical evidence of isolated adrenarche and only one had evidence of true puberty. Cortisol levels were similar in patients and controls at zero time (10.6 +/- 1.8 micrograms/dL [292 +/- 50 nmol/L] vs 10.8 +/- 1.4 micrograms/dL [298 +/- 39 nmol/L]) and at 60 minutes (26.6 +/- 2.5 micrograms/dL [734 +/- 69 nmol/L] vs 24.9 +/- 1.9 micrograms/dL [687 +/- 52 nmol/L]) after insulin hypoglycemia (all values are the mean +/- SE). During an eight-hour infusion of ACTH, cortisol responses in the patients with thalassemia were not significantly different from those of controls. Baseline levels of the adrenal androgens dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEA-S) were significantly lower in the subjects with thalassemia compared with controls of similar bone age and pubertal status. The prolonged ACTH infusion caused a significant increase in the DHEA level (79.2 +/- 14.7 ng/dL [2.74 +/- 0.51 nmol/L] vs 538.6 +/- 38.1 ng/dL [18.67 +/- 4.79 nmol/L]) and the DHEA-S level (37.5 +/- 10.8 micrograms/dL [1.02 +/- 0.29 mumol/L] vs 70.5 +/- 18.3 micrograms/dL [1.19 +/- 0.50 mumol/L]) in the patients. The patients' peak stimulated levels of DHEA-S were significantly lower than those of the controls, whereas peak levels of DHEA were similar in the patients and the controls. These results indicate that combined multiple transfusions and chelation therapy preserve the integrity of the ACTH-cortisol axis in patients with thalassemia. The reduced levels of adrenal androgens, short stature, and delayed puberty noted in our patients suggest, however, that alternative approaches to the therapy of thalassemia are needed.
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PMID:Adrenal function in thalassemia major following long-term treatment with multiple transfusions and chelation therapy. Evidence for dissociation of cortisol and adrenal androgen secretion. 302 28

The response of GH to acute administration of GH-releasing hormone (GHRH) was evaluated in 19 patients with thalassemia major and 8 normal children. In 13 of the 19 patients, GHRH induced a definite increase (greater than 5 ng/ml) in plasma GH levels, with peaks occurring 5-45 min postinjection. In 6 patients there was little or no GH rise after GHRH treatment. Overall, the mean GH response to GHRH of patients with thalassemia was lower than that of normal children. These data indicate that in thalassemia major, in addition to the described defect at the hepatic GH receptor or postreceptor level which impedes generation of somatomedins, there may be a marked impairment in somatotroph function. In one patient in whom the GH response to GHRH was superimposable on that of normal subjects, there was a blunted GH response to insulin hypoglycemia. This finding indicates that functional damage in hypothalamic structures for GH control can also occur in thalassemic patients.
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PMID:Impaired growth hormone (GH) response to GH-releasing hormone in thalassemia major. 307 70

Diabetes mellitus in patients receiving hypertransfusion for thalassemia major is usually attributed to damage to beta cells. To determine whether iron overload leads to insulin resistance before the development of insulin deficiency, insulin was infused (by euglycemic insulin-clamp technique) into 12 children with thalassemia (4 of whom were prepubertal, and 8 pubertal) who had normal or only moderately impaired glucose tolerance and who were receiving chelation therapy. Although insulin-stimulated glucose metabolism in the prepubertal children with thalassemia was similar to that in controls (normal prepubertal children) (319 +/- 23 vs. 314 +/- 41 mg per square meter of body-surface area per minute, P not significant), the response to insulin was markedly impaired in the pubertal children with thalassemia (155 +/- 18 vs. 224 +/- 15 mg per square meter per minute in normal pubertal controls, P less than 0.01). Plasma insulin levels rose excessively after oral glucose administration in the pubertal subjects with thalassemia, but not in the prepubertal patients (P less than 0.001). Furthermore, in response to a standard hyperglycemic stimulus, insulin levels in the pubertal patients rose to two to three times greater than normal and C-peptide levels became significantly elevated. Our data suggest that insulin resistance and increased insulin secretion develop in older children with thalassemia treated with long-term hypertransfusion therapy before the development of diabetes.
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PMID:Insulin resistance and hyperinsulinemia in patients with thalassemia major treated by hypertransfusion. 328 Oct

In order to evaluate the influence of haemosiderosis on the glucose metabolism we studied tissue sensitivity to insulin and the metabolic clearance rate (M.C.R.) of this hormone by means of euglycemic clamp technique using an artificial endocrine pancreas in 8 patients with thalassaemia intermedia and 8 control subjects. During the steady-state of euglycemic-hyperinsulinemic clamp (40 mU/m2/min) plasma insulin values were significantly lower and the insulin M.C.R. was significantly higher in thalassaemic patients compared to the controls. To achieve a comparable steady-state insulin concentration to the controls, we performed for a second time the euglycemic clamp in the thalassaemic patients increasing the insulin infusion rate to 80/mU/m2/min. The insulin M.C.R., the M index and the M/IRIs-s ratio were significantly higher in the thalassaemic patients compared to the controls. These results are indicative of an increased tissue peripheral sensitivity to insulin as well as the metabolic clearance rate of this hormone.
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PMID:The euglycemic clamp in patients with thalassaemia intermedia. 330 77

An increased incidence of diabetes mellitus and glucose intolerance has been reported in thalassaemia major treated with a high transfusion programme (HTP). To investigate beta-cell function, serum immunoreactive insulin (IRI), C-peptide (CP) and glucose were measured fasting and at 3, 6 and 10 min after i.v. administration of 1 mg glucagon in 20 thalassaemia patients treated by many transfusions and in nine healthy control subjects. Fasting C-peptide concentrations (mean +/- SEM) were higher in the thalassaemic group (2.15 +/- 0.17 ng/ml) than in the controls (1.41 +/- 0.13 ng/ml). After stimulation with glucagon, C-peptide concentrations were consistently higher (P less than 0.01) by approximately 50% in the thalassaemic than in the control group (5.29 +/- 0.31 vs 3.36 +/- 0.21 ng/ml, at 3 min; 5.22 +/- 0.30 vs 3.53 +/- 0.21 ng/ml at 6 min and 4.69 +/- 0.27 vs 3.30 +/- 0.17 ng/ml after 10 min). Plasma IRI concentrations increased in both groups after glucagon stimulation but were not significantly different. The glucose values were approximately 15% higher at each sampling time in the thalassaemic group than those of the normal subjects. It is concluded that disturbances in carbohydrate metabolism in thalassaemia major treated with HTP are the consequence of hepatic cirrhosis which accompanies secondary haemosiderosis, and possibly iron deposition in the beta-cells of the pancreas.
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PMID:A study of beta-cell function after glucagon stimulation in thalassaemia major treated by high transfusion programme. 332 97

Diabetes mellitus was observed in 29 of 448 patients with thalassaemia major attending seven Italian centres. Twelve patients, at onset of clinical diabetes, presented with an asymptomatic glycosuria, 13 with ketosis, and four with ketoacidosis. All were diagnosed after 1979, at a mean age of 17 years. Mean age at diagnosis of diabetes was lower in patients born in the last two decades. In these patients transfusions were started at a younger age and pre-transfusion haemoglobin concentration, serum ferritin concentration, incidence of liver disease, and the presence of a family history of diabetes were higher than in patients born previously. Although 27 (93%) cases had iron chelating treatment the mean serum ferritin concentration was 5600 micrograms/l; 25 (92%) of these patients had signs of liver impairment. The determination of C peptide in 10 patients showed a wide variation in pancreatic beta cell function, and insulin requirements ranged between 0.15 and 1.72 U/kg body weight. Metabolic control was generally poor. The onset of diabetes mellitus was followed in most patients by the appearance of other endocrine or cardiac complications, or both. Fourteen patients died within three years of presenting with overt diabetes. Haemosiderosis, liver infections, and genetic factors seemed to be crucial in diabetes development. Thalassaemic patients developing clinical diabetes mellitus are at high risk for other complications and should be strictly monitored, especially for thyroid impairment.
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PMID:Insulin dependent diabetes in thalassaemia. 334 50

Exocrine and endocrine pancreatic functions were studied in 30 patients with homozygotic beta-thalassaemia. All were treated with continuous subcutaneous deferoxamine infusions for a mean period of 30 months. Three patients (aged 18-22 years) had insulin-dependent diabetes, two before and one shortly after the onset of deferoxamine administration. There was no improvement during the treatment. An abnormal glucose tolerance test was demonstrated in 14 patients (47%) before and in seven (23%) during deferoxamine infusion. Enzyme activity of alpha-amylase and lipase as an expression of exocrine pancreatic function was normal in all during the observation period. Improvement in endocrine pancreatic function was apparently age-dependent: the younger the patient at the onset of treatment the more likely is normalization of the oral glucose tolerance test.
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PMID:[Continuous subcutaneous deferoxamine infusions in thalassemia major. Improvement in glucose tolerance]. 348 6

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

Previous studies have shown that serum levels of the somatomedin, nonsuppressible insulin-like activity (NSILA-S), are extremely low in patients with thalassemia major. Since these patients are not GH deficient, several other possible mechanisms for the reduced levels of NSIL-S have been explored. No evidence for the presence of NSILA inhibitors was obtained either in mixing experiments of normal serum and thalassemic sera or after acid gel chromatography of thalassemic sera. The high iron and ferritin levels of thalassemia had no effects on the NSILA-S bioassay itself or on the binding of GH to its hepatic receptors. GH molecules secreted as a result of exercise-induced GH stimulation tests were shown to be both immunologically and biologically reactive. No circulating GH-binding proteins were present in thalassemic sera. Since the liver function in the group of patients included in this study was only slightly abnormal, it is considered unlikely that generalized hepatic damage due to the severe iron overload of thalassemia is a major cause. These results suggest that neither NSILA-S inhibitors, abnormal GH molecules, nor hepatic damage contribute to the failure of these patients to produce NSILA-S and that a specific defect may exist at the hepatic GH receptor or postreceptor level.
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PMID:Studies on the possible mechanism for deficiency of nonsuppressible insulin-like activity in thalassemia major. 625 46


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