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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sixty full-term gravidas were divided into four groups, normal insidious iron deficiency, mild iron deficient anemia and moderate iron deficient anemia, according to their iron nutritional state determined by the measurement of hematologic and iron biochemical indexes. The iron nutritional state of newborns in each group and the level and the affinity of transferrin receptor in placenta were also studied. The iron nutritional state of newborns was found to decrease mildly along with the decrease of their mothers' iron nutritional state, especially the decrease of serum ferritin, but the differences were not statistically significant. It was suggested that the iron nutritional state of newborns was relatively normal although their mothers were in severe iron deficiency. The differences of transferrin receptor levels were significant among the four groups, the mild IDA group had the highest level of transferrin receptor, which was 1.68 times of normal group and 1.77 times of moderate IDA group. The differences between each two groups were significant. The differences of dissociate constant (Kd) of transferrin receptor were not significant among the four groups, indicating that the iron metabolism between mothers and their babies was regulated not by changing the affinity of transferrin binding to its receptor but by changing the numbers of transferrin receptor to maintain the relative stableness of newborns iron nutritional state.
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PMID:[Effect of placental transferrin receptors on iron nutritional state of normal full-term gravidas and their newborns]. 133 10

To gain insights at the molecular level into the expression of iron-regulated genes [transferrin (Tf), transferrin receptor (TfR), and ferritin H and L subunits] in human intestinal areas relevant to iron absorption, the steady-state levels of specific messenger RNAs (mRNAs) were analyzed in gastric and duodenal samples obtained from 6 normal subjects, or 10 patients with anemia, 14 patients with untreated iron overload, and 8 patients with various gastrointestinal disorders. No Tf mRNA was detected in human gastroduodenal tissue, confirming earlier findings in the rat. In normal subjects, although higher levels of ferritin H- and L-subunit mRNAs were consistently found in duodenal than in gastric samples, no differences in the content of TfR transcripts were detected. However, a dramatic increase in TfR mRNA levels was specifically found in duodenal samples from subjects with mild iron deficiency but severe anemia. This response of the TfR gene is presumably secondary to decreased cellular iron content due to its accelerated transfer into the bloodstream, as also indicated by the low levels of ferritin subunit mRNAs found in the same tissue samples, and is not linked to faster growth rate of mucosal cells because no changes in duodenal expression of histone, a growth-related gene, were detected. In patients with secondary iron overload, a down-regulation of duodenal TfR gene expression and a concomitant increase in ferritin mRNA content were documented. On the contrary, a lack of TfR gene down-regulation and an abnormally low accumulation of ferritin H- and L-subunit mRNAs were detected in the duodenums of subjects with idiopathic hemochromatosis. Whether these molecular abnormalities in idiopathic hemochromatosis are relevant to the metabolic defect(s) of the disease is presently unknown.
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PMID:Regulation of transferrin, transferrin receptor, and ferritin genes in human duodenum. 153 99

Recent studies have shown that the serum transferrin receptor is a sensitive, quantitative measure of tissue iron deficiency. This study was undertaken to determine the serum transferrin receptor's ability to distinguish iron-deficiency anemia from the anemia of chronic inflammation and to identify iron deficiency in patients with liver disease. The mean transferrin receptor level in 17 normal controls was 5.36 +/- 0.82 mg/L compared with 13.91 +/- 4.63 mg/L in 17 patients with iron-deficiency anemia (p less than 0.001). The mean serum receptor level was normal in all 20 patients with acute infection, including five with acute hepatitis, and was also normal in 8 of 10 anemic patients with chronic liver disease. Receptor levels were in the normal range in all but 4 of 41 patients with anemia of chronic disease. We conclude that unlike serum ferritin levels, which are disproportionately elevated in relation to iron stores in patients with inflammation or liver disease, the serum transferrin receptor level is not affected by these disorders and is therefore a reliable laboratory index of iron deficiency anemia.
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PMID:Serum transferrin receptor distinguishes the anemia of chronic disease from iron deficiency anemia. 158 89

TH1 and TH2 helper T cell clones have been studied with respect to their sensitivity to inhibition of DNA synthesis by an IgG anti-transferrin receptor antibody (ATRA), the iron chelator deferoxamine, and the combination of the two reagents. TH1 clones are very sensitive to ATRA-mediated inhibition of DNA synthesis while TH2 clones are very resistant, but both TH1 and TH2 clones show significant down-modulation of surface transferrin receptors after ATRA exposure. TH2 clones exhibit larger chelatable iron storage pools than TH1 clones, however, and even partial chelation of TH2 cell storage iron does not fully convert a TH2 clone to the ATRA sensitivity pattern of a TH1 clone. It is therefore proposed that the greater resistance of TH2 clones to ATRA mediated inhibition derives from the combined effects of larger and less labile iron storage pools. These studies provide novel evidence indicating that nonuniform iron metabolism can exist within the T cell compartment and thus raise questions as to why such differences exist and how they can be integrated into models of the T cell activation process. These studies also suggest that the cell-mediated immune response in vivo, which is known to be sensitive to iron deficiency, may be evoked by effector cells which resemble TH1 clones insofar as iron metabolism is concerned.
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PMID:Role of iron in T cell activation: TH1 clones differ from TH2 clones in their sensitivity to inhibition of DNA synthesis caused by IgG Mabs against the transferrin receptor and the iron chelator deferoxamine. 182 64

Measurements of circulating transferrin receptor provide a sensitive quantitative index of tissue iron deficiency in otherwise healthy subjects. This investigation was undertaken to examine the diagnostic utility of this new iron index in pregnancy. A battery of iron-related measurements, including serum transferrin receptor concentrations, was performed on 176 women in third-trimester pregnancy who were attending a university prenatal clinic. The mean receptor concentration of 5.96 +/- 2.37 mg/L (+/- 1 SD) did not differ significantly from concentrations in nonpregnant individuals and the frequency distributions were likewise comparable. Elevations in serum receptor greater than 8.5 mg/L occurred only in women with depleted iron stores defined by serum ferritin concentrations. Abnormal concentrations were found in 11 of 13 women with overt iron-deficiency anemia. Our findings indicate that serum receptor concentrations are not influenced by pregnancy per se and are a sensitive index of iron deficiency. By combining serum receptor and serum ferritin measurements, the entire spectrum of iron status in pregnancy can be assessed.
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PMID:Serum transferrin receptor for the detection of iron deficiency in pregnancy. 195 24

After decreasing in the first trimester of pregnancy, the total red blood cell mass increases in the second and third trimesters to peak at term at about 120% to 125% of nonpregnant values, but how this is brought about by changes in the rate of erythropoiesis is not known. We evaluated erythropoiesis by measuring serum transferrin receptor (TfR) levels in 406 women during normal pregnancy (N = 317), at delivery (N = 63), or in the early postpartum (N = 27). Despite the presence of the placenta and the frequent occurrence of iron deficiency, TfR levels remained low in the first two trimesters and increased in the third trimester and at delivery. To explain why erythropoiesic activity was relatively low in early pregnancy, we also measured serum immunoreactive erythropoietin (Epo) in relation to the degree of anemia. There was a very strong correlation between serum TfR and Epo levels in the entire group (r = .59, P less than .0001) as well as in each period of pregnancy. Epo levels remained low for the degree of anemia and did not correlate with hematocrit in the first two trimesters, but recovered afterwards. In the early postpartum, Epo production and erythropoiesis were normal. We conclude that: (1) erythropoiesis is decreased in the first part of pregnancy but increases afterwards; and (2) blunted Epo production in early pregnancy could be responsible for that observation.
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PMID:Blunted erythropoietin production and decreased erythropoiesis in early pregnancy. 173 97

Recent studies indicate that serum transferrin receptor levels are a quantitative index of tissue receptor mass. To determine whether the latter plays a role in the regulation of iron absorption, we examined the relationship between serum receptor, serum ferritin and iron absorption in healthy subjects. Using radioisotopic techniques we measured absorption of inorganic iron in 174 subjects and dietary nonhaem iron in 60 subjects. With both forms of iron, the correlation with absorption was far lower for serum receptor than for serum ferritin and was no longer significant when subjects with depleted iron stores were excluded. These results indicate that in normal subjects the iron store is the main physiological determinant of iron absorption and that in the absence of iron deficiency, tissue receptor mass, reflected by serum transferrin receptor levels, has no discernible influence.
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PMID:Serum transferrin receptor as an index of iron absorption. 220 11

Recent studies have provided immunological evidence for the existence of transferrin receptor in human serum and have revealed that its concentration is a sensitive measure of erythropoiesis and iron deficiency. The present study was undertaken to establish the molecular identity of this immunoreactive component. Purification from human serum was accomplished by immunoaffinity chromatography using, as the ligand, monoclonal antitransferrin receptor antibody. The receptor preparation contained two major components with Mr of 75,000 and 85,000, which were identified as transferrin and transferrin receptor, respectively. The physicochemical and immunochemical properties of the 85,000 serum receptor were compared with those established for intact placental transferrin receptor. The serum receptor exhibited an apparent Mr = 85,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under non-reducing conditions, as compared with 190,000 for placental transferrin receptor. Upon reduction, the Mr of serum receptor was unaltered, whereas, the 190,000 placental receptor dimer decreased to the expected monomer value of 95,000. Amino-terminal amino acid sequence analysis revealed that residues 1-19 of serum receptor were identical to residues 101-119 of intact receptor. These findings provide physicochemical evidence for the existence of transferrin receptor in human serum, establish its molecular identity as a truncated form lacking the cytoplasmic and transmembrane domains (residues 1-100) of intact receptor, and demonstrate that it exists as a transferrin-receptor complex in serum.
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PMID:Serum transferrin receptor is a truncated form of tissue receptor. 222 63

Intact transferrin receptor molecules complexed with transferrin were found in human plasma. The concentration of receptors was determined by an enzyme-linked immunosorbent assay that uses polyclonal antibodies. The mean concentration of 8,279 micrograms/L in 56 normal adults appears to be unrelated to age or sex. Additional receptor measurements were performed on plasmas from 260 subjects with erythropoietic disorders. Decreased concentration of plasma receptors was found in patients with erythroid hypoplasia and increased numbers in those with erythroid hyperplasia. Ferrokinetic measurements of erythropoiesis were compared with numbers of receptors in 148 subjects, and a close correlation was found (r = .86). Both sets of values, measured in different conditions and expressed in relation to normal, were consistent with expected values. Receptor values were unproportionally increased only in conditions of iron deficiency. It is concluded that plasma receptors have a constant relationship to tissue receptors, and their number in most instances reflects the rate of erythropoiesis.
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PMID:Intact transferrin receptors in human plasma and their relation to erythropoiesis. 229 84

A combination of biochemical quantitation and immunohistochemistry has been used to examine in detail transferrin receptor distribution and expression in the rat small intestine and its relationship to iron absorption. Receptor numbers were quantitated by transferrin binding to preparations of basolateral or brush-border membranes. Receptors were demonstrated on the basolateral membranes of the gut cells, but not on the brush-border fraction. Apotransferrin demonstrated little binding to basolateral membranes at physiological pH. Dietary or parenteral iron loading of animals produced a significant decline in transferrin binding, whereas binding was increased in iron deficiency. These data were confirmed by immunohistochemical studies using a monoclonal antibody to the transferrin receptor. When iron absorption was increased threefold following acute hemolysis and without a decrease in body iron stores, there was no change in transferrin receptor number. These data indicate that intestinal transferrin receptors may be regulated by body iron stores but suggest that they are not directly involved in iron absorption.
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PMID:Transferrin receptor distribution and regulation in the rat small intestine. Effect of iron stores and erythropoiesis. 229 64


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