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Query: UMLS:C0019045 (hemoglobinopathies)
 2,704 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The prevelance of IDA in industrialized countries has declined in recent decades, but there has been little change in the worldwide prevalence. IDA is currently estimated to affect more than 500 million people. Recent studies have indicated that anemia per se, the most common manifestation of iron deficiency, is less important from a public health standpoint than liabilities associated with tissue iron deficiency. The most important of the latter are an impairment in psychomotor development and cognitive function in infants and preschoolers, a deficit in work performance in adults, and an increase in the frequency of low birth weight, prematurity, and perinatal mortality in pregnancy. There have been several recent advances in combatting nutritional iron deficiency. One of the major problems has been in distinguishing iron deficiency from other causes of anemia seen epidemiologically such as malaria, HIV infection, chronic inflammation, hemoglobinopathies, and protein energy malnutrition. When combined with serum ferritin and hemoglobin determinations, the serum transferrin receptor assay is a valuable addition in epidemiologic surveys because it provides a quantitative measure of functional iron deficiency and it distinguishes true IDA from the anemia of chronic disease. The most difficult challenge is to develop effective methods of supplying iron to large segments of a population. Supplementation with iron tablets is suitable for only brief periods of need such as during pregnancy. The poor compliance with existing supplementation programs is believed to be due mainly to the gastrointestinal side effects of oral iron which can be eliminated by the use of a gastric delivery system. The most effective long-term strategy is to increase the intake of bioavailable iron in the diet. The customary approach has been to fortify a food staple such as wheat, rice, sugar, or salt, and thereby increase the iron intake of the entire population. However, because of concerns about the risk of cancer and heart disease in individuals with high iron stores, there is an increasing reluctance to supply iron to individuals who do not require it. A more effective strategy is to fortify food vehicles that are targeted to segments of the population at greatest risk of iron deficiency such as infants and school children. Because of the strong inhibitory properties of diets in regions of the world where iron deficiency is most prevalent, the use of NaFeEDTA has important advantages for food fortification.
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PMID:Iron deficiency: the global perspective. 788 26

Hemoglobin A2 levels in members of an African American family with -88 C-->T beta(+)-thalassemia were measured, and two patients in whom iron deficiency anemia developed were evaluated during treatment. Iron deficiency may diminish the level of HbA2 in healthy control subjects and in patients with heterozygous beta-thalassemia; in addition, it may reduce the amount of variant hemoglobin in certain hemoglobinopathies. Although iron deficiency appeared to be associated with a reduction in HbA2 quantity in the patient with heterozygous beta-thalassemia, the level of HbA2 did not fall below the range characteristic of beta-thalassemia. It had been proposed that mutations in the beta-globin gene promoter may be associated with higher-than-expected levels of HbA2. However, this "mild" beta-globin gene promoter mutation did not seem to result in HbA2 concentrations higher than anticipated in the heterozygous beta-thalassemias.
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PMID:Case report: effects of iron deficiency and the -88 C-->T mutation on HbA2 levels in beta-thalassemia. 848 91

An attempt was made to create an expert system with sufficient accuracy to diagnose classes of anemia and report presumptive diagnoses directly on the hematology form. The system should simulate the processes of human experts who can reliably achieve diagnostic separability by pattern analysis. A hybrid expert system combining rule-based and artificial neural network (ANN) models was constructed to evaluate microcytic anemia in a 3-layered program using hematocrit (HCT), mean corpuscular volume (MCV), and coefficient of variation of cell distribution width (RDWcv) as inputs. These measurements are available as standard output on most hematology analyzers. Three categories of microcytic anemia were considered, iron deficiency (IDA), hemoglobinopathy (HEM), and anemia of chronic disease (ACD). A novel feature of the model is its construction and training using human expert input alone. Model construction is described in detail. The model's performance was evaluated with actual case data. It was successful in correctly classifying 96.5% of 473 documented cases of microcytic anemia and anemia of chronic disease. It thus exhibits sufficient accuracy for it to be considered for use in reporting microcytic anemia diagnoses on hematology forms.
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PMID:An expert system to diagnose anemia and report results directly on hematology forms. 868 71

Microcytosis is a highly prevalent finding during blood examination. This study investigates the causes of microcytosis (defined as mean corpuscular volume (MCV) < 82 fl) in 466 patients referred to our laboratory for suspected hemoglobinopathy. The following data were obtained: Hb, MCV, serum iron, transferrin, ferritin, HbA2, HbF, isoelectric focusing of the Hb, gene mapping of chromosome 16 with Xba I and Bgl II and hybridization with an alpha- and a zeta-probe, inflammatory status. Results show that iron deficiency remains the first cause of microcytosis (35.2% of our patients), even in a selected population such as ours. Deletional alpha-thalassemia, probably the most frequent hemoglobinopathy throughout the world, represents the second most frequent cause of microcytosis (31.1%), followed by beta-thalassemia heterozygous state (18.9%). Of our patients, 1.3% had microcytosis due to the presence of an abnormal hemoglobin (HbC, Hb S/C, HbE). Three cases (0.6%) had other possible causes of microcytosis. Of the remaining 60 cases, 28 had an inflammatory state. Finally, 32 cases (6.9%) remain unexplained; taking into consideration the origin of these cases, their hematological parameters and their family history, we postulate that these cases are at high risk for non-deletional alpha-thalassemia.
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PMID:Investigation of microcytosis: a comprehensive approach. 869 32

The characteristics of familiar atypical microcytosis studied during one year were evaluated. Out of 149 patients with microcytosis in whom iron deficiency was ruled out, a heterogenous beta-thalassemia was diagnosed in 72 cases, a heterozygous delta beta-thalassemia in 16 cases and a hemoglobinopathy in 3 cases. The microcytosis was related to an inflammatory anemia in 12 cases and to an hemopathy in 9 cases. An atypical microcytosis was detected in 37 patients. A familiar and molecular analysis was carried out to detect alpha-thalassemia in cases with atypical microcytosis. It was possible to complete the familiar and molecular analysis in 35 out of 37 cases, and an alpha-thalassemia was observed in 31 patients. Most cases proved to be heterozygous or homozygous-alpha 3.7-thalassemia. No patient with heterozygous alpha zero-thalassemia was found. Most cases of familiar atypical microcytosis in our country are due to -alpha 3.7-thalassemia. Bearing these findings in mind, this analysis should only be used in situations where a problem of prenatal diagnosis is present. Moreover, systematic molecular analysis of familiar atypical microcytosis could be justified if the MCV is lower than 75 fl.
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PMID:[Atypical familial microcytosis: a familial and genetic study]. 954 23

The prevalence and age distribution of anemia and malaria among Yanomami Amerindians undergoing sociocultural assimilation are described. Anemia and malaria proportions were determined in 103 individuals randomly selected from 515 villagers in Mavaca in the southern Venezuelan Amazon. The age and sex distribution reflected that of the entire village cluster. Anemia (hematocrit less than World Health Organization/Centers for Disease Control and Prevention reference values) was found in 91% of the study population. As a group, adults (> or = 15 years old) had the highest proportion of anemia (P=0.037). Adult females had lower mean hematocrit values than adult males (P=0.013). The anemia was predominantly hypochromic and microcytic (62%), a finding that could suggest a diagnosis of iron deficiency in the absence of known hereditary hemoglobinopathies in these Amerindians. Malaria was diagnosed in 14% overall. Children (< 10 years old) displayed the highest proportion of Plasmodium falciparum (17%) and P. vivax (14%) parasitemia, splenomegaly (94%), and fever (34%) (P=0.059, 0.039, 0.005, and 0.008, respectively). The high proportions of anemia and splenomegaly observed in the survey may be used as indicators of inadequately controlled malaria in this community. Further studies to assess the epidemiology of risk factors for the high prevalence of anemia, and predominance of P. falciparum infections in the area are urgently needed.
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PMID:Anemia and malaria in a Yanomami Amerindian population from the southern Venezuelan Amazon. 988 12

Iron deficiency is the most frequently encountered cause of suboptimal response to recombinant human erythropoietin (rHuEPO). Carefully assessing iron status is of paramount importance in chronic renal failure patients prior to or during rHuEPO therapy. Because there is great need for iron in the EPO-stimulated erythroid progenitors, it is essential that serum ferritin and transferrin saturation levels should be maintained over 300 microg/liter and 30%, respectively. Investigators have shown that oral iron is unlikely to keep pace with the iron demand for an optimal rHuEPO response in uremics. Therefore, patients with iron deficiency will always require intravenous iron therapy. The early and prompt iron supplementation can lead to reductions in rHuEPO dose and hence cost. After the iron deficiency has been corrected or excluded, we must remember all of the possible causes of hyporesponsiveness in every rHuEPO-treated patient. As dose requirements vary, it is not clear which dose of rHuEPO causes this hyporesponsiveness. However, if the patient with iron repletion does not respond well after the induction period, the major causes blunting the response to rHuEPO should be investigated. Most factors are reversible and remediable, except resistant anemia associated with hemoglobinopathy or bone marrow fibrosis, which requires a further increase in the rHuEPO dose. By means of early detection and correction of the possible causes, the goal of increasing therapeutic efficacy can be achieved. Iron overload may lead to an enhanced risk for infection, cardiovascular complication, and cancer. Over-treatment with iron should be avoided in dialysis patients, despite the fact that the safe upper limit of serum ferritin to avoid iron overload is not clearly defined. On the other hand, functional iron deficiency may develop even when serum ferritin levels are increased. Controversy remains as to whether intravenous iron therapy can overcome this form of hyporesponsiveness in iron-overloaded patients. Moreover, a treatment option of iron supplementation is not warranted in these patients, as the potential hazards of iron overload will be worsened. We demonstrated that the mean hematocrit significantly increased from 25.1+/-0.9% to 31+/-1.2% after eight weeks of intravenous ascorbate therapy (300 mg three times a week) in 12 hemodialysis patients with serum ferritin levels of more than 500 microg/liter. The enhanced erythropoiesis paralleled with a rise in transferrin saturation (27.8+/-2.5% vs. 44.8+/-9.5%, P < 0.05) and reductions in erythrocyte zinc protoporphyrin (130+/-32 vs. 72+/-19 micromol/mol heme, P < 0.05) and monthly rHuEPO dose (24.2+/-4.5 vs. 16.8+/-3.4 x 10(3) units, P < 0.05) at the end of study. It is speculated that ascorbate supplementation not only facilitates the iron release from storage sites and its delivery to hematopoietic tissues, but also increases iron utilization in erythroid cells. Our study provides a more complete understanding of the pathogenesis of iron overload-related anemia and the development of an adjuvant therapy, intravenous ascorbic acid, to the existing treatments.
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PMID:Erythropoietin hyporesponsiveness: from iron deficiency to iron overload. 1008 94

HbOThrace is an abnormal hemoglobin which is constructed by defective beta chains (Glu121-->Lys121). It mostly characterises the Muslim minority of the Thrace region. During the last 6 years, our department detected HbOThrace in 118 cases. Four groups were formed, the first consisted of cases of HbOThrace trait with normal iron and ferritin levels, the second of cases of HbOThrace hemoglobinopathy, the third of cases of HbOThrace/Hb beta zero hemoglobinopathy and the fourth of cases of HbOThrace trait with low iron and ferritin levels. The second, third and fourth group were compared with the first one. The conclusion is that the presence of HbOThrace leads to a mild hypochromic anemia, with no clinical findings, but the coexistence of beta zero gene or iron deficiency produces more pronounced laboratory findings and even clinically evident anemia.
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PMID:HbOThrace trait, HbOThrace hemoglobinopathy and HbOThrace/Hb beta zero hemoglobinopathy: a retrospective study of 118 cases. 1020 93

The sickle cell hemoglobinopathy is a major public health problem which causes high morbidity and mortality in India. Although the hematological and clinical profile of the patients is extensively studies. The reproductive outcome of mothers afflicted with sickle cell trait and disease is still unknown in India. In a retrospective study, we have examined the reproductive profile of 190 mothers afflicted with sickle cell, attending Medical Out-Patient Department at V.S.S. Medical College Hospital, Burla in Western Orissa, India during the year 1991-1992. Seventy-three mothers who were found normal after medical examination and were free from hemoglobinopathic disorders, anemia, jaundice, iron deficiency, etc. constituted the control group and 66 mothers with sickle cell trait and 51 with sickle cell disease formed the study group. The reproductive history was recorded for number of conceptions, fate of offspring, live birth, surviving children and childhood mortality. Hematological investigations and hemoglobin electrophoresis were done as per the standard procedure. There was no difference in mean number of livebirths per mother between controls and sickle cell trait mothers. But between the controls and sickle cell homozygotes (p < 0.01), and sickle cell trait and disease (p < 0.01) mothers, this mean number was significant. For abortions/miscarriages, the difference between controls and sickle cell homozygotes (p < 0.001), and sickle cell trait and disease (p < 0.01) mothers was highly significant. The number of stillbirths per mother in homozygous sickle cell mothers was higher (p < 0.01) as compared to controls. There were significantly higher childhood deaths in sickle cell trait (p < 0.05) and disease (p < 0.05) mothers than in the controls. It seems that the sickle cell heterozygote and hemoglobin E heterozygote mothers are genetically better fit than the sickle cell homozygotes. Further, the sickle cell disease is clinically severer than the hemoglobin E disease in India probably due to molecular diversity.
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PMID:Fetal outcome and childhood mortality in offspring of mothers with sickle cell trait and disease. 1077 16

Anemia is the most prevalent nutritional problem worldwide, due mainly to iron deficiency. Studies of anemia are less common in adolescents than in women and children. We examined anemia prevalence in adolescent Kuwaiti schoolgirls, and its association with hemoglobinopathies as well as the most common environmental cause, Fe deficiency. A cross-sectional sample of 1051 healthy adolescent schoolgirls was studied. Sample size was based on WHO criteria. Anemia, Fe deficiency and hemoglobin (Hb) variations were studied by Hb concentration, erythrocyte protoporphyrin (EP) and an HPLC quantitation, respectively. Of the subjects sampled, 30% were anemic. Mildly elevated EP values were found in 68%. Girls with high EP levels were more likely (P < 0.001) to be anemic than girls with normal EP. Up to 25% of the girls may have had Fe deficiency anemia. Hemoglobinopathies were neither prevalent nor significantly associated with anemia. These data indicate that environmental factors play a significant role in anemia among healthy, well-to-do Kuwaiti adolescent girls.
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PMID:Iron deficiency is a more important cause of anemia than hemoglobinopathies in Kuwaiti adolescent girls. 1080 21


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