Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0162316 (iron deficiency anemia)
 3,806 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Erythropoietin (EPO) is a prime stimulating factor for red cell production. EPO is a glycoprotein which has a molecular weight of 34,000, and is mainly produced by the kidney. EPO stimulates the differentiation and proliferation of erythroid progenitor cells in the bone marrow. The rate of production of EPO is regulated primarily by renal oxygen availability. Because anemia reduces renal oxygen availability, anemic stress accelerates EPO production in the kidney. Recently, EPO has mainly been determined by radioimmunoassay. Serum EPO titer is usually inversely correlated with hemoglobin concentration, as typically shown in iron deficiency anemia. Serum EPO titers in aplastic anemia are much higher than those in iron deficiency anemia relative to the hemoglobin concentration. Serum EPO titers in anemia caused by malignancies sometimes differ considerably among patients. Serum EPO in renal anemia usually show low titers irrespective of the degree of anemia. Serum EPO titers in untreated polycythemia vera are lower than those in treated polycythemia vera or secondary polycythemia. Determination of serum EPO is useful in differential diagnosis of polycythemia vera. Recombinant human EPO has been used to treat various anemias including renal anemia, refractory anemia, anemia in malignancies and secondary anemia. Determination of serum EPO titers is also valuable in many other situations of clinical medicine.
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PMID:[Erythropoietin determination in clinical medicine]. 835 Apr 98

The transferrin receptor plays a critical role in iron metabolism by precisely controlling the flow of transferrin iron into body cells. A soluble truncated form of the receptor can be detected in human serum using sensitive immunoassays, and the initial clinical experience with this new measurement indicates that it reflects the total body mass of tissue receptor. Serum receptor levels rise significantly with tissue iron deficiency and the heightened demand for iron associated with expansion of the erythroid marrow. The serum receptor provides a quantitative measure of functional iron deficiency and distinguishes the associated anemia from that of chronic disease. If iron deficiency is excluded, the serum receptor provides a quantitative measure of total erythropoiesis that is more sensitive and less invasive than bone marrow examination currently used to assess red cell precursor mass. Performed in conjunction with serum ferritin measurements, the serum receptor will be useful in establishing the true prevalence of iron deficiency anemia in population studies.
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PMID:Serum transferrin receptor. 847 68

A 35-year-old female was referred to our hospital for fever and anemia. Physical examination was unremarkable. Complete blood count revealed microcytic hypochromic anemia and reticulocytopenia. The bone marrow cellularity was normal. Some giant pronormoblasts were seen but other erythroid cells were absent. No stainable iron was seen. Parvovirus B19 (PVB19) DNA was detectable by polymerase chain reaction. Anti-PVB19 IgM-antibody was also positive in the serum on admission. Antibodies against rubella, measles, mumps, EB virus and HBs were negative and HBs antigen was also negative. Thus the diagnosis of iron deficiency anemia complicated with pure red cell aplasia secondary to PVB19 infection was made. The PVB19 DNA was still positive on days 6 and 11, suggesting that PVB19 virus persists as long as 3 weeks after the onset of PVB19 infection. However, the erythroid cells had recovered by day 6 after admission suggesting that the development of IgM antibody successfully protected the erythroid cells from infection by the residual PVB19. Hence, careful observation for PVB19 DNA and the antibody may be necessary if immunodeficient patients developed anemia of unknown etiology.
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PMID:[Transient pure red cell aplasia in an adult with acute parvovirus B19 infection: observation of PVB19 DNA by polymerase chain reaction, viral antibody and erythroid cells in the bone marrow]. 851 Mar 37

We studied erythropoiesis in 31 patients with vitamin B12 deficiency by measuring serum erythropoietin (s-Epo), serum transferrin receptor (s-TfR, taken as an index of total erythroid activity), reticulocyte count, and the reticulocyte maturation index (RMI). s-Epo and s-TfR were measured with commercial immunoassays, whereas reticulocyte count and RMI were determined by flow cytometry. s-Epo (123 +/- 196 U/L) and s-TfR (4.1 +/- 2 mg/L) levels were increased in patients with vitamin B12 deficiency. The absolute reticulocyte counts were decreased (29 +/- 18 x 10(9)/L) with a relative increase in the most immature fractions (RMI: 29.6 +/- 18%). A significant negative relationship was found between s-Epo and Hb level (r = -0.65, p < 0.0001). On the average, however, s-Epo was inappropriately low for the degree of anemia, since the observed/predicted (O/P) s-Epo ratio was 0.80 +/- 0.28 in vitamin B12 deficiency vs 1.00 +/- 0.16 in a group of patients with iron deficiency anemia. It is concluded that at least a portion of patients with vitamin B12 deficiency have serum erythropoietin levels that are inappropriately low for the degree of anemia.
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PMID:Serum erythropoietin and erythroid activity in vitamin B12 deficiency. 910 86

The Sysmex R-3000 (TOA Medical Electronics, Kobe, Japan) evaluates maturation of reticulocytes by quantitating the fraction of reticulocytes within low-, middle-, and high-fluorescence intensity regions. We defined the immature reticulocyte fraction (IRF) as the sum of the fraction of high-fluorescence intensity regions plus the fraction of middle-fluorescence intensity regions. Then, we studied the clinical significance of IRF in the evaluation of anemia by comparing the IRF with the absolute reticulocyte count (ARC) and with the reticulocyte production index (RPI) and by reviewing pertinent clinical information about the patients. In the study, 132 specimens from 102 patients undergoing evaluation of anemia were analyzed. By using simple regression analysis, our results showed that the IRF has a weak but significantly positive correlation with ARC and with RPI, indicating that IRF is an additional useful parameter to evaluate the erythropoietic activity in anemia. Interpretation by integrating IRF and reticulocyte enumeration (ARC and RPI) provided useful information for further subclassification of anemia. Increased IRF (IRF > or = 0.23) and increased ARC generally indicated an adequate erythroid response to anemia. All but three specimens with an IRF less than 0.23 showed an RPI of 2 or less. These specimens were from patients with underlying diseases known to lead to decreased erythropoietic activity, predominantly chronic renal insufficiency. Specimens with a subnormal or normal ARC (with a corresponding RPI < or = 2) but with an IRF of more than 0.23 were from patients with various underlying conditions, including acute infection, iron deficiency anemia, human immunodeficiency virus infection, sickle disease with crisis, pregnancy, and myelodysplastic syndrome. Our results indicate that an IRF of 0.23 or less in patients with anemia reflects bone marrow that is nonresponsive or underresponsive to the anemia. Patients with an increased IRF (IRF > or = 0.23) may require further examination to clarify the cause of the anemia.
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PMID:Clinical significance of immature reticulocyte fraction determined by automated reticulocyte counting. 920 80

The bone marrow reports of 1966 patients admitted to a provincial teaching hospital between January, 1992 to April, 1995 were retrospectively analyzed. Twenty-six (1.3%) bone marrows showed the presence of malarial parasites. Sixteen (62%) patients had Plasmodium falciparum 9 (34%) Vivax malaria and one (4%) mixed infection. All these patients gave a history of prolonged illness and had low parasite counts. Plasmodium vivax malaria was not associated with any significant pathology in the bone marrow, except iron deficiency anaemia. The bone marrows with Plasmodium falciparum malaria showed myeloid hyperplasia, erythroid hyperplasia, megaloblastosis and hypoplasia in different proportions. No evidence of dyserythropoiesis was found in this series. The possible mechanisms producing these changes and the factors responsible for the discrepancy in bone marrow findings in different geographical areas are discussed.
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PMID:Bone marrow changes in human malaria: a retrospective study. 923 May 80

Serum erythropoietin (sEpo) concentration is primarily related to the rate of renal production and, under the stimulus of hypoxia, increases exponentially as hemoglobin (Hb) decreases. Additional factors, however, appear to influence sEpo, and in this work, we performed studies to evaluate the role of the red blood cell precursor mass. We first compared the relationship of sEpo with Hb in patients with low versus high erythroid activity. The first group included 27 patients with erythroid aplasia or hypoplasia having serum transferrin receptor (sTfR) levels < 3 mg/L (erythroid activity < 0.6 times normal), while the second one included 28 patients with beta-thalassemia intermedia having sTfR levels > 10 mg/L (erythroid activity > 2 times normal). There was no difference between the two groups with respect to Hb (8.3 +/- 1.6 v 8.0 +/- 1.3 g/dL, P > .05), but sEpo levels were notably higher in patients with low erythroid activity (1,601 +/- 1,542 v 235 +/- 143 mU/mL, P < . 001). In fact, multivariate analysis of variance (ANOVA) showed that, at any given Hb level, sEpo was higher in patients with low erythroid activity (P < .0001). Twenty patients undergoing allogeneic or autologous bone marrow transplantation (BMT) were then investigated. A marked increase in sEpo was seen in all cases at the time of marrow aplasia, disproportionately high when compared with the small decrease in Hb level. Sequential studies were also performed in five patients with iron deficiency anemia undergoing intravenous (IV) iron therapy. Within 24 to 72 hours after starting iron treatment, marked decreases in sEpo (up to one log magnitude) were found before any change in Hb level. Similar observations were made in patients with megaloblastic anemia and in a case of pure red blood cell aplasia. These findings point to an inverse relationship between red blood cell precursor mass and sEpo: at any given Hb level, the higher the number of red blood cell precursors, the lower the sEpo concentration. The most likely explanation for this is that sEpo levels are regulated not only by the rate of renal production, but also by the rate of utilization by erythroid cells.
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PMID:Red blood cell precursor mass as an independent determinant of serum erythropoietin level. 949 Jul 1

Microcytic anemia (mk) mice and Belgrade (b) rats have severe iron deficiency anemia due to defects in intestinal iron transport and erythroid iron utilization. Both animal mutants carry the same missense mutation in Nramp2, the first mammalian iron transporter to be identified. This mutation, in which glycine 185 is changed to arginine (G185R), occurs within predicted transmembrane domain 4 of the protein. We have performed site-directed mutagenesis of murine Nramp2, focusing on amino acids of transmembrane domain 4 that are highly conserved among Nramp-like proteins. We have expressed each mutant form in transfected cells and examined iron transport function, subcellular localization, and protein amounts. All tested forms of Nramp2 localize to the plasma membrane and to transferrin-containing endosomes. Most transmembrane domain 4 mutations affect the amount of protein detected and consequently show diminished iron transport. The G185R mutation, however, causes near total loss of Nramp2 function that cannot be fully explained by a decreased amount of protein, indicating that G185R disrupts iron transport through an alteration in the function of Nramp2, rather than degradation of the protein.
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PMID:The G185R mutation disrupts function of the iron transporter Nramp2. 973 Oct 75

The relationship between serum erythropoietin (EP) and hemoglobin (Hb) concentrations was investigated in patients of iron deficiency anemia (IDA) in the course of iron replacement therapy to elucidate how the therapy induced changes in that relationship. At first Hb-dependent EP levels were determined in 123 IDA patients prior to the treatment by the third-degree logarithmic regression of EP on the Hb deficit (d-Hb). Following the start of iron supply, the deviation of observed EP values from the predicted level (EPc), i.e., delta-EP, was most obvious at the next phase of the onset of reticulocyte crisis; however, this deviation reduced with the alleviation of IDA. The value in maximum phase (delta-EPmx), as individually defined for each of 95 patients, correlated significantly with the severity of the pretreatment ID state (r = 0.502, p < 0.01). Partial correlation analysis revealed that about 80% of this gap was attributable to the ID state. Also, it was assumed that EP upregulation was twice that attributable to the Hb-deficit factor alone. The phase sequence of the delta-EP versus d-Hb relationship in 21 relapsed patients demonstrated a different rout from that observed in their improvement phase. The ID state-induced upregulation of EP, i.e., EPc, was followed by a therapy-induced overshooting drop that was attributable to acute uptake of EP by shifted erythroid precursors. From the viewpoint of erythropoietic regulation, the subsequent down-regulation of EP in the mid to late phases was considered appropriate for the prevention of Hb over production.
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PMID:[Decrease serum erythropoietin level induced by iron replacement therapy in patients with iron deficiency anemia]. 1035 37

The concentration of the soluble fragment of transferrin receptor in serum is an important new hematological parameter. Clinical and laboratory studies have shown that this serum form of the receptor reflects the total body mass of cellular transferrin receptor, 80% of which is contained in the erythroid marrow. The two disorders that result in an elevation in the serum transferrin receptor are anemias associated with enhanced erythropoiesis and tissue iron deficiency. The concentration of soluble transferrin receptor provides a useful quantitative measure of the erythroid marrow mass and thereby assists clinically in categorizing the type of anemia. The most important clinical use of the serum transferrin receptor is in determining the cause of iron deficient erythropoiesis (that is, identifying iron deficiency anemia whether it occurs alone or in the presence of the anemia of chronic disease). Present evidence supports the routine use of the serum transferrin receptor in the clinical evaluation of anemic patients.
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PMID:The measurement of serum transferrin receptor. 1052 54


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