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Query: UMLS:C0002874 (aplastic anemia)
 5,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fanconi's anemia (FA) is an autosomal recessive condition in which greater than 90% of the homozygotes develop aplastic anemia. To determine the relation between erythroid progenitors and clinical status, blood and marrow mononuclear cells were cultured in methyl cellulose with erythropoietin, plus other hematopoietic growth factors, and growth in normal oxygen (20%) was compared with growth in low, physiologic oxygen (5%). Peripheral blood cultures were performed from 24 patients, and marrows from six. Patients were classified into six clinical groups. Group 1: Severe aplasia, transfused; one patient; no erythroid progenitors. Group 2: Severe, transfused, androgen unresponsive; one patient; no blood burst-forming units-erythroid (BFU-E). Group 3: Androgen responsive; eight patients, with decreased blood BFU-E. Group 4: Aplastic, about to start treatment; two patients; below normal numbers of colony-forming units-erythroid (CFU-E) and BFU-E. Group 5: Stable, with mild anemia, and/or thrombocytopenia, and/or macrocytosis; seven patients; with below normal numbers of blood BFU-E. Group 6: Hematologically normal; five patients; blood BFU-E low normal to normal. One marrow had normal numbers of CFU-E and BFU-E. Incubation in 5% oxygen doubled CFU-E and BFU-E only in the patients with close to normal or normal growth in 20% oxygen. Hemin and interleukin-3 increased growth slightly in those cultures where there was some growth with erythropoietin alone. Our data show that there is a correlation between current clinical status and in vitro erythropoiesis. Cultures of erythroid progenitors may also be useful predictors of hematologic prognosis in FA, although our follow-up period is too short to prove this hypothesis.
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PMID:Erythropoiesis in Fanconi's anemia. 185 79

Serial serum erythropoietin levels were measured in 10 consecutive patients undergoing allogeneic bone marrow transplantation. Observed erythropoietin levels are compared with those predicted from a large control population of anaemic patients not receiving chemotherapy. There was an initial acute rise in serum erythropoietin, peaking between days 1 and 4 after marrow transfusion, which was unrelated to changes in haemoglobin concentration. Patients maintained serum erythropoietin concentrations at around twice the predicted level for the first 2 weeks following transplantation, with a gradual fall into the expected range by wk 3. Erythropoietin levels did not change with episodes of bacterial infection or acute graft-versus-host disease. A patient with severe aplastic anaemia had initial successful engraftment with normalisation of erythropoietin levels, but showed a marked and amplified rise in erythropoietin 2 wk before falling peripheral blood counts indicated failure of the bone marrow graft.
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PMID:Changes in serum erythropoietin levels during allogeneic bone marrow transplantation. 188 86

One of the most important factors for the proliferation and hemoglobin synthesis of erythroid cells is iron atom. This atom is tightly bound to serum transferrin (Tf) and is taken up by erythroblasts and reticulocytes through transferrin receptor (TfR). Both Tf and TfR are reutilizable and have roles for the efficient intracellular accumulation of iron. In addition to the reutilization (recycling), the expression of TfR is also regulated by cytoplasmic iron concentration; the increase of iron downregulate the synthesis of TfR at the translational level and vice versa. This mechanism was recently explained by the binding between "iron responsive element (IRE)" in the 5' end of TfR mRNA and IRE binding protein by a transacting manner. Johnstone et al, and we found that TfR was externalized from sheep reticulocyte and human erythroleukemia cell, K562, respectively. Furthermore, we confirmed that this shed TfR was detected in blood and concluded that the quantitation of TfR in serum is a useful index for evaluating the erythropoiesis. The serum TfR was increased in iron deficiency anemia, hemolytic anemia and polycythemia and was decreased in aplastic anemia. In renal anemia, it was increased after the administration of erythropoietin (Epo). By the in vitro liquid culture of peripheral blood stem cells using interleukin 3 and Epo, it was found that soluble TfR was derived from the erythroblasts during the maturation process.
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PMID:[Expression and extracellular release of transferrin receptors on erythropoiesis]. 189 Jul 32

Twenty-three patients with bicytopenia or pancytopenia were retrospectively studied. The patients with underlying disorders, blast count of more than 5% on bone marrow (BM) aspirate, blast count of more than 1% on peripheral blood or ringed sideroblast count of more than 15% on BM aspirate were excluded. According to Yoshida's criteria, 23 patients were classified into 6 subtypes [AA (aplastic anemia)1: typical AA, AA2: atypical AA, MDS (myelodysplastic syndrome)3: typical RA (refractory anemia, MDS4-6: atypical RA], and AA1 7 cases; AA2 2 cases; MDS3 5 cases; MDS4 1 case; MDS5 2 cases; MDS6 6 cases. To clarify the clinical features of atypical RA group (MDS4-6), we investigated ferrokinetics, RBC life span, karyotype, serum Epo (erythropoietin) concentration, response to therapy and prognosis. Results were as follows: 1) all three RA patients who were younger than 30 years old were included in atypical RA group, 2) in ferrokinetics study PID (plasma iron disappearance time) values of MDS4 and MDS6 patients ranged between those of AA1 and those of MDS3 patients (5 of 7 patients), 3) two cases who developed leukemia belonged to typical RA group, 4) patients with atypical RA showed response to therapy and their prognosis were better than those with typical RA. These observations suggest that atypical RA have different clinical features from typical RA.
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PMID:[Clinical features of atypical refractory anemia (RA)]. 194 25

A 69-year-old female was admitted for pancytopenia. The hematological examination showed leukocytes 1,800/microliters, hemoglobin 5.3 g/dl and platelets 9.6 x 10(4)/microliters. A bone marrow aspiration revealed hypoplasia, but no abnormal cells. Serum erythropoietin titer was 5,100 mU/ml. Diagnosis of aplastic anemia was made. She received 400 ml of blood transfusion twice, and was then treated with recombinant human erythropoietin (rHuEPO) (12,000 U/day) three times a week for eight weeks. Hemoglobin level gradually increased to the level of 12.0 g/dl. This case suggests that there are some cases of aplastic anemia which can respond to treatment with rHuEPO.
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PMID:[Remarkable improvement of anemia by administration of recombinant human erythropoietin in a patient with aplastic anemia]. 194 34

For clinical studies with erythropoietin (EPO), enzyme-linked immunosorbent assays for the determination of EPO and EPO antibodies were developed. Using polyclonal and monoclonal EPO antibodies in a sandwich technique, serum EPO levels greater than 10 pg/ml (corresponding to 1 mU/ml, calibrated with the 2nd WHO IRP EPO) can be determined. In 103 healthy blood donors, a mean (+/- SD) value of 36 +/- 19 pg EPO/ml was found. Very high EPO concentrations were found in patients suffering from myelodysplastic syndrome and aplastic anemia; elevated levels were associated with rheumatoid arthritis and myelomatosis. No EPO antibodies were detectable in EPO-treated patients.
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PMID:New enzyme-linked immunosorbent assay methods for measurement of serum erythropoietin levels and erythropoietin antibodies. 209 85

Several agents including drugs, chemicals and viruses are known to induce agranulocytosis, aplastic anemia, and leukemia. The recent identification, characterization and cloning of several peptide regulatory factors, including granulocyte-macrophage-colony stimulating peptide regulatory factor (GM-CSF), erythropoietin, and interleukins and a study of their actions, suggest that agents producing agranulocytosis, aplastic anemia, and leukemia may interfere with the action of these factors. The agents that are capable of inducing these diseases and the various peptide regulatory factors have positive and/or negative actions on the prostaglandin system. Prostaglandins are known to be involved in the maturation and differentiation of the progenitor cells of the bone marrow and in erythropoietin-mediated erythropoiesis. Since prostaglandins influence immune response, modify genetic damage induced by drugs and chemicals, modulate gene action, and have feed-back control on the actions of peptic regulatory factors, it is likely that prostaglandins are involved in the pathogenesis of agranulocytosis, aplastic anemia, and leukemia. If so, this may lead to new therapeutic strategies in these hematological conditions.
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PMID:Agranulocytosis, aplastic anemia, and leukemia: relevance to arachidonic acid metabolism. 211 Jun 77

Treatment of aplastic anemia may raise considerable problems in some patients. This report concerns a boy whose illness started at 11 years of age. At first admission laboratory data were: hemoglobin 7.5 g/l, and counts of leucocytes, neutrophils and platelets were 2.3, 0.6, and 8 x 10(9)/l, respectively. His bone marrow was hypoplastic with sparse erythropoiesis. The patient did not respond to traditional medical treatment. Serum contained a high concentration of erythropoietin but no antibodies against erythropoietin. The patient's serum did neither alone, nor supported with recombinant erythropoietin, stimulate erythropoiesis in a bioassay, suggesting that some factor(s) inhibiting erythropoietic activity was present. Based on this hypothesis, plasma exchange was performed. After 26 weeks of plasmapheresis the hematological parameters were normalized. We conclude that plasmapheresis might be an alternative in treatment of resistant aplastic anemia. Further diagnostic tools to identify patients who might benefit from such a treatment are required.
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PMID:Treatment of refractory aplastic anemia with plasmapheresis: report of a case in childhood with review of the literature. 220 69

In a dose escalation study we tested the feasibility and tolerance of high-dose recombinant human erythropoietin (r-HuEPO) therapy in four patients with ineffective erythropoiesis due to myelodysplastic syndromes (MDS) or paroxysmal nocturnal hemoglobinuria (PNH). Recombinant human EPO was administered i.v. with an initial dose of 50 U/kg body weight (BW) three times per week. The dose was increased by steps of 25 or 50 U/kg bW with intervals of 1-4 weeks up to a maximum dose of 500 U/kg BW three times per week. All patients were treated as outpatients. Pre-study treatment with cyclosporin A and/or Danazol was continued in three patients. In one patient r-HuEPO was discontinued after 20 weeks because of relapse of severe aplastic anemia. No major side effects were observed even at the maximum dose. One patient with PNH showed an increase of hemoglobin from 89 to 139 g/liter that permitted monthly phlebotomies to reduce his iron overload. In one patient with MDS the reticulocyte count increased from 2.5 to 50 x 10(9)/liter, and the transfusion requirement decreased to 2 U every 3-4 weeks instead of every 2 weeks. Two patients did not complete the whole treatment period and showed no rise in reticulocyte count. We conclude that high dose r-HuEPO therapy is feasible in patients with anemia due to MDS or PNH. High-dose r-HuEPO appears to have some effect on anemia due to ineffective erythropoiesis in a subgroup of patients. Further studies are needed to identify potential responders and to define the optimal administration of r-HuEPO.
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PMID:High-dose recombinant human erythropoietin for treatment of anemia in myelodysplastic syndromes and paroxysmal nocturnal hemoglobinuria: a pilot study. 222 80

The development of a 24 hour radioimmunoassay for erythropoietin (EPO) using EPO derived from recombinant DNA as both immunogen and ligand is described in the present paper. Mixed breed rabbits immunized with 10 micrograms/kg of EPO derived from a stably transfected cell line (Elanex Pharmaceuticals Inc., Bothel, Washington, USA, through McDonnell Douglas Corp., St. Louis, Missouri, USA; "MD") produced antibodies to EPO with high titer (up to 1:896,000 final dilution in the tube), high affinity (8.4 x 10(11) liter/M), and good specificity. Purified EPO from the above source or from AmGen Biologicals (Thousand Oaks, California, USA; "AG") were successfully radioiodinated with the chloramine-T method and used as ligand in the radioimmunoassay. Standard dose-response curves prepared with EPO from both commercial sources were not significantly different and showed a sensitivity of 0.75 to 0.96 mU/tube. The dose-response curves in both systems also showed parallelism with serially diluted serum from a patient with aplastic anemia. Within-assay and between-assay precision were determined by assaying multiple replicates of a serum pool. Recovery of exogenous EPO added to a serum pool averaged 97% for both systems. The range of normal human serum EPO was determined by assaying the sera of 153 hematologically-normal adult subjects and was found to be 1.1 to 27.3 mU/ml for MD EPO and 0.5 to 16.7 mU/ml for AG EPO. Sera from several patients with hematologic abnormalities were also assayed, including those of 36 patients with anemia of end-stage renal disease (mean +/- SEM, 29.5 +/- 4.0 mU/ml; P less than 0.01). In conclusion, this new, more rapid and sensitive radioimmunoassay system can be used to measure EPO levels in sera from normal human subjects and patients with several types of anemia, and should also be very useful in therapeutic drug monitoring of patients receiving EPO from various commercial sources.
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PMID:Development of a new radioimmunoassay for erythropoietin using recombinant erythropoietin. 226 82


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