Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002895 (sickle cell disease)
 11,747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nutritional surveys have demonstrated that Hb levels in blacks are consistently lower than in whites. This difference does not appear to be related to socioeconomic dietary differences, or differences of hereditary disorders such as sickle cell disease. We studied 47 black and 63 white subjects drawn from hospital employees. Mean Hb of black men was 0.9 g/dl less than that of white men. Mean Hb of black women was 0.5 g/dl less than that of white women. This difference was not associated with differences of serum iron, iron binding capacity, or transferrin saturation. Ferritin values of white women were significantly less than values observed in white men, but similar differences were not observed between black men and women. The explanation for this is unclear although may be related to sample size or differences of menstrual status. Copper levels were lower in white men than in any other group, and zinc levels were essentially similar between racial groups. The red blood cells of blacks were also smaller than those of whites. This difference could not be explained by disordered Hb synthesis. These observations confirm that Hb concentrations in both black men and women are lower than in their white counterparts. This difference cannot be explained by differences in iron, copper, or zinc nutriture. Further, measurements of Hb in nutritional survey populations reflect iron status as only one of several variables and should not be used as the only assessment of iron nutrition.
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PMID:Racial differences of hemoglobin concentration: measurements of iron, copper, and zinc. 728 95

Cerebrovascular accidents (CVA) as a complication of sickle cell disease occur most frequently in childhood. Life-long transfusion prevents recurrent stroke, but inevitably leads to iron overload. Although effective chelation exists, many patients are not compliant. Erythrocytapheresis, an automated method of red blood cell exchange, was evaluated as an alternative to control transfusion-related iron load. Eleven patients with sickle cell anemia and a history of stroke were converted from simple transfusion to pheresis. Total time on pheresis for the group averaged 19 months (range 4-36 months). No significant complications occurred with a mean pre-pheresis hemoglobin S (Hb S) level of 44%. Blood utilization increased by an average of 50%. The effect of pheresis on serum ferritin depended on the patient's pre-pheresis ferritin level and chelation regimen. Ferritin levels remained stable for chelated patients with ferritin levels > or = 5,000 ng/ml, but decreased in a chelated patient with a pre-pheresis ferritin level of 4,000 ng/ml. For non-chelated patients with significant pre-pheresis iron load, ferritin levels remained stable. No patient on chelation prior to pheresis was able to discontinue deferoxamine. However, one patient with pre-pheresis ferritin of 500 ng/ml maintained serum ferritin levels < 200 ng/ml for 36 months of pheresis without chelation. Pheresis is more expensive than simple transfusion unless the cost of chelation and organ damage from iron overload are considered. Erythrocytapheresis is a safe method of controlling Hb S levels and limiting or preventing iron load in chronically transfused sickle cell patients.
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PMID:Erythrocytapheresis limits iron accumulation in chronically transfused sickle cell patients. 972 73

Cerebrovascular accident (CVA) is a major complication of sickle cell disease during childhood. Long-term transfusion reduces the hemoglobin S level and generally prevents recurrent stroke, but it also results in progressive iron overload that requires regular chelation therapy. Erythrocytapheresis offers an alternative approach aimed at reducing the iron accumulation. We reviewed the results of erythrocytapheresis in eight sickle cell patients (mean age of 12.1 years) at high risk for a first or recurrent stroke. They were maintained at the standard pre-transfusion hemoglobin S (Hb S) level of 30%. Over an average of 9 months of erythrocytapheresis, none of the patients developed complications related to the procedure or to the increased blood use. Ferritin levels decreased by a mean of 26.5% in all patients. When evaluating the ferritin level in five patients, who remained on chelation therapy with deferoxamine (DFO), the level dropped by a mean of 32%. The levels remained stable in the three patients who were not on DFO. The procedure is safe and effective in reducing iron overload and can obviate the need for chelation therapy, even when the target Hb S is maintained at the standard 30% range.
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PMID:Erythrocytapheresis for chronically transfused children with sickle cell disease: an effective method for maintaining a low hemoglobin S level and reducing iron overload. 1054 Mar 66

We compared 48-hour urinary iron excretion after a twice-daily subcutaneous bolus injection of deferoxamine and after 12 hours of subcutaneous continuous infusion of the drug in 27 patients with iron overload (mean age, 55.7 years). In most patients, the iron overload was due to multiple transfusions administered during chemotherapy or as part of supportive care for a hematologic or oncologic disorder. One patient had sickle cell anemia and 1 had hereditary hemochromatosis and spherocytosis. Similar urinary iron excretion was observed with the 2 methods of administration; mean +/- SD values were 6935.3 +/- 3832.3 microg/48 hours with subcutaneous bolus injection and 6630.4 +/- 3606.9 microg/48 hours with subcutaneous continuous infusion (P =.3). Twenty-six patients (96.3%) chose to continue therapy with bolus injection. The long-term efficacy of bolus injection was evaluated by measuring the serum ferritin concentration at regular intervals for a follow-up time of 20.1 +/- 4.5 months. Ferritin concentration decreased to below 1000 microg/L in 73% of the patients and to below 500 microg/L in 42% and became normal in 26%. Best results were obtained in patients who were no longer receiving blood transfusions when chelation therapy was initiated. Three of 26 patients (11.5%) had mild, transient side effects after bolus injection. Larger prospective, randomized studies must be conducted before deferoxamine bolus injection can be routinely recommended for patients with iron overload. (Blood. 2000;95:2776-2779)
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PMID:Safety and efficacy of subcutaneous bolus injection of deferoxamine in adult patients with iron overload. 1077 20

In sub-Saharan Africa, anaemia in pregnancy results from multiple causes including malaria, iron deficiency and haemoglobinopathies. In a cross-sectional study among 530 pregnant women in Ghana in November-December 1998, red blood cell indices were analysed with respect to malaria, serum concentrations of ferritin and C-reactive protein (CRP), and the haemoglobin and alpha-globin genotypes. Anaemia (haemoglobin [Hb] < 11 g/dL) was found in 54% of the women; 63% harboured malaria parasites at predominantly low numbers. Ferritin levels were considerably influenced by malaria and inflammatory processes (CRP > 0.6 mg/dL). Depending on the definition applied, the prevalence of iron deficiency ranged between 5% and 46%. The HbAS trait was observed in 14%, HbAC and elevated HbF in 7% each, and sickle cell disease in 1%. Heterozygous beta-thalassaemia was present in 1% of the women and alpha(+)-thalassaemia in 33% (29% heterozygous, 4% homozygous). Women with HbAS had higher malaria parasite densities than those with HbAA. In individuals with highly elevated HbF (> 10%), parasitaemia occurred in 27% only. Low gravidity, second trimester of pregnancy, malaria, raised CRP levels, and homozygous alpha(+)-thalassaemia were independent risk factors for anaemia in multivariate analysis. alpha(+)-Thalassaemia, however, was associated with a lesser degree of malarial anaemia when compared to non-thalassaemic women. Iron deficiency appears not to be a major health problem in this population. Haemoglobinopathies are common but, except for homozygous alpha(+)-thalassaemia, do not substantially contribute to anaemia in pregnancy. alpha(+)-Thalassaemia ameliorates malarial anaemia in pregnant women.
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PMID:Anaemia in pregnant Ghanaian women: importance of malaria, iron deficiency, and haemoglobinopathies. 1113 70

Magnetic resonance imaging (MRI) appears to be useful for monitoring iron overload in thalassaemia. We studied 106 patients with beta-thalassaemia: 80 with thalassaemia major (TM) and 26 with thalassaemia intermedia (TI). Thirty-five patients with sickle cell disease (SCD) were also evaluated. Serum ferritin, liver and myocardial T2-relaxation time and liver iron concentration (LIC) were measured. LIC values, based on biopsies from 29 patients, showed a close inverse correlation with the respective liver T2-values, along with a strong positive correlation with ferritin levels in all patients. Heart T2-values correlated with left ventricular ejection fraction in TM and SCD, but not in TI patients. Both liver and heart T2-values were significantly lower in TM patients than those of TI, and SCD patients. Ferritin levels showed a strong correlation with liver T2-values in all three groups of patients. Similarly, a negative correlation was found between serum ferritin levels and heart T2-values in TM, but not in TI and SCD patients. Heart and liver T2-values showed a significant correlation only in TM patients. These results suggest that the MRI technique (T2 relaxation time) used in our study, is a reliable, safe and non-invasive method for the assessment of the deposition of iron in the liver; results for the heart become reliable only when there is heavy iron deposition.
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PMID:Magnetic resonance imaging in the evaluation of iron overload in patients with beta thalassaemia and sickle cell disease. 1532 28

Iron overload is not uncommon in sickle cell disease (SCD) and requires regular chelation therapy in several instances. The present study evaluates the effect of deferiprone in 15 adult patients with SCD (ten beta(s)/beta(0)thalassemia and five beta(s)/beta(s)) and iron overload. Deferiprone was given at a dose of 75 mg/kg daily for 12 months. The evaluation considered pre- and post-treatment values of serum ferritin, urinary iron excretion, and T2 values of liver and heart obtained by magnetic resonance imaging (MRI). Eleven patients had a liver biopsy prior to starting therapy to evaluate iron concentration (LIC). Twelve patients completed the study with satisfactory compliance. In ten of them (83.3%) the serum ferritin levels decreased significantly at the end of the trial; in eight patients (66.6%) the reduction of serum ferritin was accompanied by a significant increase of their liver T2 values. All patients had a significant increase of urinary iron excretion in response to the drug. Ferritin levels and liver T2 values correlated with liver iron concentration; on the contrary, ferritin levels and liver T2 values failed to show any correlation with heart T2 values. Heart T2 values did not also show any correlation with left ventricular ejection fraction. Deferiprone was well tolerated and did not cause any significant adverse effects. These results suggest that deferiprone may effectively decrease the iron deposition in patients with SCD; moreover, T2 MRI proves to be a reliable and rapid, noninvasive method for assessing the liver iron load in patients with SCD.
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PMID:Deferiprone as an oral iron chelator in sickle cell disease. 1580 85

We tracked the results of 394 manual or automatic red blood cell exchanges done with a cell separator in 20 sickle cell patients at high risk for recurrent complications. Over an average of 6 years, none of the patients developed complications related to the procedure or to the increased blood use. It was safe and effective in preventing complications of sickle cell disease, and if done automatically, reduced iron overload. Ferritin levels also decreased in patients treated with automatic red blood cell exchange. Furthermore, using Single Donor Red Blood Cell units (SDRC) we reduced the potential exposure to transfusion transmitted infectious diseases (TTI).
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PMID:Chronic red blood cell exchange to prevent clinical complications in sickle cell disease. 1590 76

R2* magnetic resonance imaging (R2*-MRI) can quantify hepatic iron content (HIC) by noninvasive means but is not fully investigated. Patients with iron overload completed 1.5T R2*-MRI examination and liver biopsy within 30 days. Forty-three patients (sickle cell anemia, n = 32; beta-thalassemia major, n = 6; and bone marrow failure, n = 5) were analyzed: median age, 14 years, median transfusion duration, 15 months, average (+/-SD) serum ferritin 2718 plus or minus 1994 ng/mL, and average HIC 10.9 plus or minus 6.8 mg Fe/g dry weight liver. Regions of interest were drawn and analyzed by 3 independent reviewers with excellent agreement of their measurements (intraclass correlation coefficient = 0.98). Ferritin and R2*-MRI were weakly but significantly associated (range of correlation coefficients among the 3 reviewers, 0.41-0.48; all P < .01). R2*-MRI was strongly associated with HIC for all 3 reviewers (correlation coefficients, 0.96-0.98; all P < .001). This high correlation confirms prior reports, calibrates R2*-MRI measurements, and suggests its clinical utility for predicting HIC using R2*-MRI. This study was registered at www.clinicaltrials.gov as #NCT00675038.
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PMID:R2* magnetic resonance imaging of the liver in patients with iron overload. 1926 77

Ferroportin Q248H mutation has an allele frequency of 2.2-13.4% in African populations and is associated with a mild tendency to increased serum ferritin in the general population. Some investigators have reported that ferroportin Q248H is degraded after exposure to hepcidin in exactly the same manner as wild-type ferroportin, but supraphysiological concentrations of hepcidin were used. The aim of our study was to determine whether ferroportin Q248H may have reduced sensitivity to physiological concentrations of hepcidin. The sensitivity of ferroportin Q248H to hepcidin was determined in 293T cells transiently expressing ferroportin using immunoblotting and fluorescence analysis. Ferritin concentrations were measured in these cells and also in human primary monocytes derived from humans with different ferroportin genotypes. The effect of Q248H on serum iron measures was examined in patients with sickle cell anemia. Immunoblotting and fluorescence analysis showed decreased sensitivity of ferroportin Q248H to physiological concentrations of hepcidin. Lower ferritin concentrations were observed after incubation with iron and hepcidin in 293T cells expressing ferroportin Q248H and in primary monocytes from ferroportin Q248H subjects. In sickle cell anemia, ferroportin Q248H heterozygotes had lower serum ferritin concentrations than wild-type subjects, consistent with enhanced iron release by macrophage ferroportin Q248H. A clinical benefit of ferroportin Q248H was suggested by lower echocardiographic estimates of pulmonary artery pressure in patients carrying mutant alleles. In conclusion, our results suggest that ferroportin Q248H protein is resistant to physiological concentrations of hepcidin and that this mutation has discernible effects on iron metabolism-related clinical complications of sickle cell anemia. They provide a mechanistic explanation for the effect of ferroportin Q248H on iron status in individuals of African descent and suggest that these changes in iron metabolism may be beneficial under certain disease-specific circumstances. (ClinicalTrials.gov Identifier:NCT00011648).
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PMID:Reduced sensitivity of the ferroportin Q248H mutant to physiological concentrations of hepcidin. 2306 13


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