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

Iron transport in the plasma is carried out by transferrin, which donates iron to cells through its interaction with a specific membrane receptor, the transferrin receptor (TfR). A soluble form of the TfR (sTfR) has been identified in animal and human serum. Soluble TfR is a truncated monomer of tissue receptor, lacking its first 100 amino acids, which circulates in the form of a complex of transferrin and its receptor. The erythroblasts rather than reticulocytes are the main source of serum sTfR. Serum sTfR levels average 5.0+/-1.0 mg/l in normal subjects but the various commercial assays give disparate values because of the lack of an international standard. The most important determinant of sTfR levels appears to be marrow erythropoietic activity which can cause variations up to 8 times below and up to 20 times above average normal values. Soluble TfR levels are decreased in situations characterized by diminished erythropoietic activity, and are increased when erythropoiesis is stimulated by hemolysis or ineffective erythropoiesis. Measurements of sTfR are very helpful to investigate the pathophysiology of anemia, quantitatively evaluating the absolute rate of erythropoiesis and the adequacy of marrow proliferative capacity for any given degree of anemia, and to monitor the erythropoietic response to various forms of therapy, in particular allowing to predict response early when changes in hemoglobin are not yet apparent. Iron status also influences sTfR levels, which are considerably elevated in iron deficiency anemia but remain normal in the anemia of inflammation, and thus may be of considerable help in the differential diagnosis of microcytic anemia. This is particularly useful to identify concomitant iron deficiency in a patient with inflammation because ferritin values are then generally normal. Elevated sTfR levels are also the characteristic feature of functional iron deficiency, a situation defined by tissue iron deficiency despite adequate iron stores. The sTfR/ferritin ratio can thus describe iron availability over a wide range of iron stores. With the exception of chronic lymphocytic leukemia (CLL) and high-grade non-Hodgkin's lymphoma and possibly hepatocellular carcinoma, sTfR levels are not increased in patients with malignancies. We conclude that soluble TfR represents a valuable quantitative assay of marrow erythropoietic activity as well as a marker of tissue iron deficiency.
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PMID:Soluble transferrin receptor for the evaluation of erythropoiesis and iron status. 1258 62

Anemia is a frequent clinical feature with adverse prognostic effects in patients with chronic lymphocytic leukemia (CLL). It may complicate CLL at any time during the course of the disease. Different factors concur to the occurrence of anemia in CLL, as in other lymphoproliferative diseases: leukemic bone marrow infiltration, the myelosuppressive effect of chemotherapy and inhibiting cytokines, autoimmune phenomena, hypersplenism, a poor nutritional status that leads to folic acid, vitamin B12 and iron deficiency. In addition, a defective endogenous erythropoietin (EPO) production has also been described in patients with lymphoproliferative diseases. The severity of anemia, which may be worsened by an impaired cardiopulmonary function, may profoundly compromise the patients' quality of life and, indirectly, the outcome of cancer bearing patients. Several Authors have reported the clinical activity of recombinant human (rHu)EPO in anemic patients with lymphoproliferative diseases, including CLL. Low serum EPO levels at baseline and EPO levels inappropriately low for the degree of anemia help to identify patients who are likely to respond to EPO. A clear dose-dependent response to EPO has been reported by different Authors and it has been suggested that 5,000 IU should be considered as an appropriate initial dose for the majority of patients. rHuEPO represents a potentially effective and safe therapy for the management of anemia associated with lymphoproliferative diseases. The reduction of red blood cell transfusion requirement, the improvement of quality of life through the remission of fatigue-related anemia are two important results that should be considered in the management of patients with CLL. In prospect, the availability of new rHuEPO molecules with a more prolonged half-life may open new therapeutic avenues.
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PMID:Erythropoietin and chronic lymphocytic leukemia. 1273 12

The measurement of soluble transferrin receptor (sTfR) has been proposed as a novel approach to the diagnosis of iron deficiency, especially in anaemia of chronic diseases (ACD). Our aim was to study the utility of sTfR under 'everyday conditions' as seen in a geriatric hospital in the following groups of patients: First, in a pilot group of 99 multimorbid geriatric patients (85 women, 14 men; 82.00 +/- 6.32 years) admitted for rehabilitation after recent surgical treatment of a bone fracture; second, in 677 geriatric patients (506 women, 171 men; 79.17 +/- 11.47 years) with different diagnoses admitted to a department of internal medicine; third, in some remarkable clinical cases in order to illustrate the diagnostic limits of sTfR. In general, both genders showed a remarkable age-dependent decrease in erythropoiesis. In patients with haemoglobin levels below 12.0 mg/dL, this parameter correlated significantly with sTfR. However, this was seen only in women, not in men. Moreover, an age-dependent increase in sTfR was seen in women, while in men it remained almost constant. Based on these findings, we conclude that there is a different, gender-specific aetiology of iron deficiency in the elderly. About 30% of patients of both genders simultaneously had low haemoglobin levels and low sTfR. This was interpreted as 'adaptation' or 'tolerance' to the iron deficiency. This was illustrated by a clinical case of megaloblastic anaemia: Initially low sTfR rose only during the vitamin B12 substitution and normalized after recovery. We conclude that sTfR provides an insight into the 'dynamics' of iron metabolism: A rise in sTfR indicates an 'acute readiness to refill iron stores', while a low (non-stimulated) sTfR level corresponds to the quite frequent adaptation to iron deficiency and/or inhibition of resorption. Finally, extremely high sTfR levels were observed in some cases of malignancy such as in acute leukaemia and in hypernephroma. Thus, increased sTfR levels can be caused by paraneoplastic effects.
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PMID:Soluble transferrin receptor and iron status in elderly patients. 1283 62

Iron deficiency anemia (IDA), mostly due to chronic occult bleeding from the gastrointestinal tract, is a common problem in the elderly. This study aimed to determine the prevalence of IDA in the elderly and to investigate the gastrointestinal tract in elderly patients with IDA. 1,388 patients over 65 years were prospectively evaluated for IDA in our outpatient clinic. IDA was defined if decreased hemoglobin concentrations (<13 g/dl for men and <12 g/dl for women) were associated with low serum ferritin levels (<15 ng/ml in men and <9 ng/ml in women). We evaluated the gastrointestinal system of all patients with IDA by upper gastrointestinal endoscopy and colonoscopy regardless of fecal occult blood loss. The prevalence of anemia was found to be 25% (n = 347) in our study population, and 30.5% (n = 106) of these patients with anemia had iron deficiency. Upper gastrointestinal endoscopy and colonoscopy were performed in 96 patients with IDA. Fifty-eight upper gastrointestinal system lesions (55 patients, 57.3%) and 27 colonic lesions (26 patients, 27.1%) were detected. We diagnosed gastrointestinal malignancy in 15 (15.6%) elderly patients with IDA (8 colon, 1 esophageal and 6 gastric cancers). IDA is a common problem in elderly patients; consequently, before iron replacement therapy, patients should be thoroughly investigated regarding a possible association with gastrointestinal malignancy.
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PMID:Iron deficiency anemia in the elderly: prevalence and endoscopic evaluation of the gastrointestinal tract in outpatients. 1297 53

There is growing evidence that increases in both hematocrit and body iron stores are components of the insulin resistance syndrome. The ability of insulin and of IGF-I - whose effective activity is increased in the context of insulin resistance - to boost activity of the transcription factor hypoxia-inducible factor-1alpha (HIF-1alpha), may be at least partially responsible for this association. HIF-1alpha, which functions physiologically as a detector of both hypoxia and iron-deficiency, promotes synthesis of erythropoietin, and may also mediate the up-regulatory impact of hypoxia on intestinal iron absorption. Insulin/IGF-I may also influence erythropoiesis more directly, as they are growth factors for developing reticulocytes. Conversely, the activation of HIF-1alpha associated with iron deficiency may be responsible for the increased glucose tolerance noted in iron-deficient animals; HIF-1alpha promotes efficient glucose uptake and glycolysis - a sensible adaptation to hypoxia - by inducing increased synthesis of glucose transporters and glycolytic enzymes. Recent reports that phlebotomy can increase the efficiency of muscle glucose uptake in lean healthy omnivores are intriguing and require further confirmation. Whether increased iron stores contribute to the elevated vascular risk associated with insulin resistance is doubtful, inasmuch as most prospective studies fail to correlate serum ferritin or transferrin saturation with subsequent vascular events. However, current data are reasonably consistent with the possibility that moderately elevated iron stores are associated with increased overall risk for cancer - and for colorectal cancer in particular; free iron may play a catalytic role in 'spontaneous' mutagenesis. Thus, iron excess may mediate at least some of the increased cancer risk associated with insulin resistance and heme-rich diets. People who are insulin resistant can minimize any health risk associated with iron overload by avoiding heme-rich flesh foods and donating blood regularly.
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PMID:Hyperinsulinemia may boost both hematocrit and iron absorption by up-regulating activity of hypoxia-inducible factor-1alpha. 1459 87

Cancer-related anemia often develops from the infiltration of marrow by malignant cells, impaired hemoglobin (Hb) production related to chemotherapy or radiation therapy, iron deficiency, or low endogenous erythropoietin levels. Patients with cancer-related anemia may experience cognitive dysfunction including decreased mental alertness, poor concentration, and memory problems. Anemia-mediated cerebral hypoxia may cause symptoms such as headache, vertigo, tinnitus, and dizziness. These symptoms often are exacerbated in the elderly patient with cancer and related to underlying low Hb concentrations. Restoring Hb levels via the administration of iron supplements, blood transfusions, or, more recently, erythropoiesis-stimulating therapy (epoetin alfa) results in significant improvement of cognitive function. The use of epoetin alfa as a treatment option for patients with chemotherapy-associated anemia and an Hb concentration less than 10 g/dL has been recommended by the American Society of Clinical Oncology and the American Society of Hematology. Erythropoiesis-stimulating therapies are a promising treatment option for cancer-related anemia that may improve cognitive function and quality of life for patients with cancer.
Cancer Nurs 2003 Dec
PMID:Anemia in the oncology patient: cognitive function and cancer. 1502 12

Iron deficiency is common at presentation in colorectal cancer. Testing for it may complement other screening tests such as faecal occult blood testing and sigmoidoscopy. We therefore examined the feasibility of offering iron deficiency testing to patients in a primary care setting in the UK, offering testing to all 1240 patients aged 55-74 years in one general practice in South Wales, UK. Patients with abnormal results were assessed and offered further investigations. Five hundred and fifty-one people (44.4%) attended for iron deficiency blood tests, of whom 26 patients (4.7%) were iron deficient and offered endoscopic assessment. This identified two cases of benign neoplasia amenable to treatment and no cases of cancer. Iron deficiency testing in a screening context appeared feasible although uptake may be low.
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PMID:Using iron deficiency tests for colorectal cancer screening: a feasibility study in one UK general practice. 1530 48

Diagnosing disorders of iron metabolism the concentration of the iron storing protein ferritin reflects the body's iron reserves much better than does serum iron concentrations or transferring saturation. Merely in the event of acute phase reactions is the validity of the ferretin level compromised. This applies in particular to the redistribution of iron in anemia caused by inflammatory conditions or malignancies, as also, though less markedly, to functional iron deficiency in renal anemia. Here, an additional diagnostic work-up, in particular when EPO/iron therapy is applied. Iron overload should be recognized already in the latent state before organ damage occurs. Clinically and chemically confirmed iron overload that cannot be ascribed to hematological disease, iron replacement of transfusions, should prompt a molecular-biological analysis of hemochromatosis-associated genetic defects.
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PMID:[Diagnosing disorders of iron metabolism. Begin with ferritin]. 1562 34

Anemia is common in acute critically ill patients. Although blood loss, either by trauma, surgery, phlebotomies or gastrointestinal bleeding, may play a role, the anemia in these patients bears many similarities to the anemia characteristic of chronic disease. Serum iron is low with a high concentration of ferritin and low-to-normal transferrin and serum transferrin receptor levels. Several mechanisms may be involved, with inflammation playing a crucial role. Although the exact nature of the inflammatory response and the role of various cytokines need further elucidation, it is known that inflammation blunts the responsiveness of the hormone erythropoietin and induces functional iron deficiency. Iron is trapped in cells of the mononuclear phagocytic system and its release is temporarily blocked. The bone marrow is still capable of incorporating iron and of responding to treatment with recombinant human erythropoietin (rh-EPO). The duration of the anemia is related to the persistence of the inflammation. Although the effects of anemia on morbidity and mortality in the critically ill are poorly defined, a restrictive transfusion policy, in which hemoglobin concentration is maintained between 7.0 and 9.0 g/dl, proves to be at least as effective as, if not superior to, a more liberal regimen. In individual situations, such as in cardiovascular and cancer patients, higher thresholds may be appropriate. The administration of rh-EPO is an alternative to reduce the need for red blood cell transfusions and to avoid transfusion-related complications. Although its efficacy has been shown, questions regarding cost-benefit, dose regimen and clinical outcomes need to be answered before its large-scale use can be recommended.
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PMID:Anemia in critically ill patients. 1566 82

When erythropoietin (epoetins or darbepoetin) is used to treat the anemias of chronic renal failure, cancer chemotherapy, inflammatory bowel diseases, HIV infection and rheumatoid arthritis, functional iron deficiency rapidly ensues unless individuals are iron-overloaded from prior transfusions. Therefore, iron therapy is essential when using erythropoietin to maximize erythropoiesis by avoiding absolute and functional iron deficiency. Body iron stores (800-1200 mg) are best maintained by providing this much iron intravenously in a year, or more if blood loss is significant (in hemodialysis patients this can be 1-3 g). There is no ideal method for monitoring iron therapy, but serum ferritin and transferrin iron saturation are the most common tests. Iron deficiency is also detected by measuring the percentage of hypochromic red blood cells, content of hemoglobin in reticulocytes, soluble transferrin receptor levels, and free erythrocyte protoporphyrin values, but iron overload is not monitored by these tests. Iron gluconate and iron sucrose are the safest intravenous medications.
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PMID:Iron requirements in erythropoietin therapy. 1573 95


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