Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 34-year-old man was found to have leukocytosis and thrombocytosis in 1983. In 1988, his leukocyte count was 10,400/microliter, Hb 16.5g and a platelet was 73 x 10(4)/microliter. A bone marrow examination showed megakaryocyte hyperplasia. Essential thrombocythemia (ET) was diagnosed but no treatment was given. In February 1993, anemia and hepatosplenomegaly developed and cytogenetic study of the peripheral blood demonstrated t(1;7) (q10;p10). Myelofibrosis was diagnosed as by bone marrow biopsy. The patient was treated with blood transfusion, oxymetholone and prednisolone, but without effect. In 1995, acute myeloid leukemia developed, and he died in December 1995 due to septicemia. We report here a case of the ET developed myelofibrosis with t(1;7) (q10;p10) anomaly and acute leukemia.
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PMID:[Essential thrombocythemia in transformation to acute leukemia (FAB-M0) as a natural history from myelofibrosis with t(1;7)]. 919 91

In myelodysplastic syndromes (MDS), pancytopenia and defective function of neutrophils and platelets lead to a high risk of infectious and hemorrhagic complications. The progression to acute myeloid leukemia adds to morbidity and mortality. Supportive care including red blood cell and platelet transfusions are still the cornerstone of therapeutic management. However, the clinical use of the recombinant hematopoietic growth factors has enlarged the range of therapeutic applications in patients with MDS. It is possible to reverse neutropenia in MDS patients by administration of G-CSF (granulocyte colony stimulating factor) or GM-CSF (granulocyte-monocyte colony stimulating factor). Because of the lower incidence of adverse events, G-CSF is preferable. However, neither G-CSF nor GM-CSF have been shown to reduce the rate of severe infection or mortality from infection when given prophylactically. In the case of a severe infection, therapeutic administration of G-CSF together with antibiotics might be justified in otherwise neutropenic MDS patients. Preliminary data suggest it to be possible to identify MDS patients with a higher than 50% chance of reversal of anemia or transfusion dependency by treatment with high-dose erythropoietin (EPO). Since patients with only slight impairment of erythropoiesis and no transfusion dependency have the highest response rates but need EPO the least, pharmacoeconomic analyses are urgently needed. Controlled randomized trials will have to ascertain whether combinations of EPO with G-CSF or GM-CSF are of benefit. Clinical studies with thrombopoietin (megakaryocyte growth and differentiation factor) have to be initiated to find out whether thrombocytopenia in MDS can be reversed.
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PMID:Clinical use of hematopoietic growth factors in patients with myelodysplastic syndromes. 919 74

Transcription factor GATA-1 is essential for red blood cell maturation and, therefore, for survival of developing mouse embryos. GATA-1 is also expressed in megakaryocytes, mast cells, eosinophils, multipotential hematopoietic progenitors and Sertoli cells of the testis, where its functions have been elusive. Indeed, interpretation of gene function in conventional knockout mice is often limited by embryonic lethality or absence of mature cells of interest, creating the need for alternate methods to assess gene function in selected cell lineages. Emerging strategies for conditional gene inactivation through site-specific recombinases rely on the availability of mouse strains with high fidelity of transgene expression and efficient, tissue-restricted DNA excision. In an alternate approach, we modified sequences upstream of the GATA-1 locus in embryonic stem cells, including a DNase I-hypersensitive region. This resulted in generation of mice with selective loss of megakaryocyte GATA-1 expression, yet sufficient erythroid cell levels to avoid lethal anemia. The mutant mice have markedly reduced platelet numbers, associated with deregulated megakaryocyte proliferation and severely impaired cytoplasmic maturation. These findings reveal a critical role for GATA-1 in megakaryocyte growth regulation and platelet biogenesis, and illustrate how targeted mutation of cis-elements can generate lineage-specific knockout mice.
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PMID:A lineage-selective knockout establishes the critical role of transcription factor GATA-1 in megakaryocyte growth and platelet development. 923 6

Foals infected with equine infectious anemia virus become thrombocytopenic 7 to 20 days after virus inoculation, and within a few days following the onset of detectable viremia. The thrombocytopenia is associated with suppression of platelet production. Possible mediators of suppression of thrombopoiesis include tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta (TGF-beta), cytokines that are released during inflammation. To assess effects of plasma or serum from infected foals on megakaryocyte (MK) growth and maturation in vitro, equine low-density bone marrow cells were cultured for clonogenic and ploidy assays. Neutralizing antibodies to TNF-alpha and TGF-beta were added to cultures to determine the contribution of these cytokines to suppression of thrombopoiesis. Plasma from the immediately pre-thrombocytopenia (Pre-Tp) period significantly reduced MK colony numbers. This suppression was partially reversed upon antibody neutralization of plasma TNF-alpha, TGF-beta, or both. There were no differences in ploidy distribution of MK grown in the presence of preinfection serum compared with those grown in the presence of Pre-Tp serum. These results indicate that TNF-alpha and TGF-beta may contribute to suppression of MK proliferation and represent likely factors in the pathogenesis of thrombocytopenia.
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PMID:Suppression of megakaryocyte colony growth by plasma from foals infected with equine infectious anemia virus. 931 Apr 86

Previous studies have shown that daily multiple administration of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) markedly stimulates thrombopoiesis and effectively ameliorates thrombocytopenia, and in most cases anemia and neutropenia, in myelosuppressed animals. In this study, we evaluated the effects of a single intravenous injection of PEG-rHuMGDF on hematopoietic recovery after sublethal total-body irradiation in mice. A single injection of PEG-rHuMGDF (1 to 640 microg/kg) 1 hour after irradiation accelerated platelet, red blood cell (RBC), and white blood cell (WBC) recovery in a dose-dependent fashion. In the bone marrow of vehicle-treated mice, megakaryocytic, erythroid, and myeloid progenitors, as well as day 12 colony-forming unit-spleen (CFU-S), were dramatically decreased much earlier than the nadirs of peripheral blood cells, whereas megakaryocytes were modestly decreased. Treatment with PEG-rHuMGDF (80 microg/kg, an optimal dose) 1 hour after irradiation resulted in more rapid recovery of these four hematopoietic progenitors and also significantly facilitated megakaryocyte recovery. In addition, the same PEG-rHuMGDF administration schedule expanded bone marrow cells capable of rescuing lethally irradiated recipient mice. As the interval between irradiation and PEG-rHuMGDF treatment was longer, its effects on hematopoietic recovery were attenuated. In contrast to the effects of PEG-rHuMGDF, a single injection of recombinant human granulocyte colony-stimulating factor (rhG-CSF) 1 hour after irradiation exclusively accelerated WBC recovery, but only to a similar extent as PEG-rHuMGDF (80 microg/kg) treatment even when rhG-CSF doses were escalated to 1,000 microg/kg. This appeared related to different pharmacokinetics of these two factors after a single injection in irradiated mice. The concentrations of PEG-rHuMGDF after injection persisted in the plasma for a longer time compared with rhG-CSF. These results indicate that a single injection of PEG-rHuMGDF at an early time after irradiation is able to effectively improve thrombocytopenia, anemia, and leukopenia with concomitant accelerated recovery of both primitive and committed hematopoietic progenitors in irradiated mice. Our data also show that compared with the rhG-CSF shown to exert multilineage effects on hematopoiesis, PEG-rHuMGDF has more wide-ranging effects on peripheral blood cell recovery.
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PMID:Multilineage hematopoietic recovery by a single injection of pegylated recombinant human megakaryocyte growth and development factor in myelosuppressed mice. 941 67

Neoplastic disorders sometimes accompany a renal transplant. Herein, we report a large granular lymphocyte (LGL) leukemia patient with pure red cell aplasia (PRCA) after renal transplantation. A 36-year-old female was presented to our department with anemia in February 1996. She had undergone hemodialysis because of pregnancy in December 1981. She received a renal transplantation from her mother in April 1986. After the transplantation, she received cyclosporin A (CyA) at 2 mg/kg/day, mizoribine at 1 mg/kg/day, and methylprednisolone at 0.1 mg/kg/day for 8 years. In July 1995, her hemoglobin level dropped to 9.3 g/dl, and anemia developed gradually. In January 1996, her hemoglobin was 5.8 g/dl, and she was given a red blood cell transfusion. Laboratory findings were as follows: RBC 1.46 x 10(12)/L; hemoglobin 5.8 g/dl; hematocrit 17.8%; leucocytes 5.2 x 10(9)/L with 62.4% neutrophils, 34.1% lymphocytes, 2.6% monocytes; platelets 50.8 x 10(10)/L; reticulocytes 0.4%. Bone marrow aspirate smears and biopsy sections revealed normal myeloid and megakaryocyte differentiation with few erythroid precursors. The lymphocytes were of medium size with granules in the cytoplasm. More than 90% of lymphocytes were of the LGL type. Surface markers of peripheral blood mononuclear cells demonstrated increases in the CD2+, CD3+, CD4-, and CD8+ populations. A monoclonal rearrangement of T-cell receptor (TCR)-beta chain gene was found by Southern blot analysis of the mononuclear cells in peripheral blood. A diagnosis of LGL leukemia with PRCA was made. During the next 4 months, she received six red blood cell transfusions, a total of 12 U. In March 1996, the patient was treated with cyclophosphamide (1 mg/kg/day). After 1 month of treatment, serum GPT levels increased to 60 IU/l. The dose of cyclophosphamide was reduced to 0.5 mg/kg/day. Two months after initiation of the therapy, the patient developed reticulocytosis and blood transfusion was not needed thereafter. During remission, the number of CD2+, CD3+, CD4-, and CD8+ lymphocytes decreased. Large granular lymphocytes decreased to less than 10% of peripheral blood. The monoclonal rearrangement of the TCR-beta chain gene in peripheral blood disappeared.
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PMID:Large granular lymphocyte leukemia with pure red cell aplasia in a renal transplant recipient. 942 21

Using a non-isotopic ligand binding assay using multi-colour flow cytometry, we quantitatively examined the amount of mpl in megakaryocyte-platelet lineage cells. Firstly, we quantified the amount of mpl on cell lines. Mpl gene-transfected BaF3 cells expressed a large amount of mpl, whereas original BaF3, K562, HL-60 and NOMO-1 cells showed no mpl. In bone marrow cells from healthy volunteers, mpl was expressed on CD34+ cells from the very early stage of differentiation when they had no CD38 antigen. The amount of mpl increased with differentiation to CD34+ CD41+ cells, but decreased with further differentiation to CD34- CD41+ cells. In CD34+ CD41+ cells the amount of mpl varied according to cell size: abundant in large cells, moderate in medium-size cells and a little in small cells. In bone marrow cells from patients with refractory anaemia (RA), the amount of mpl was decreased compared with that in bone marrow cells from healthy volunteers. When analysed by the same CD phenotype and same cell size, the amount of mpl was less in RA patients compared with that in healthy volunteers in all phenotypes and sizes tested. The proportion of large CD34+ CD41+ cells was less in RA patients than in normal volunteers.
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PMID:Amount of mpl on bone marrow haemopoietic precursor cells from healthy volunteers and patients with refractory anaemia. 943 17

Maf recognition elements (MAREs or NF-E2 binding sites) have been shown to be vital for erythroid- and megakaryocyte-specific gene expression. Transcription factor NF-E2 is composed of p45, a large subunit belonging to the CNC family proteins, and a small Maf subunit, and is thought to activate transcription through its binding to MAREs in both the erythroid and megakaryocytic cell lineages. While p45 gene knockout mice exhibit thrombocytopenia due to abnormal terminal differentiation of megakaryocytes, and the mutant mice die of massive bleeding within a week after birth, anemia is not apparent in these animals. Disruption of the nrf2 gene, encoding another CNC family protein, results in no hematological abnormalities. We have therefore tested the hypothesis that Nrf2 might compensate for the p45 deficiency in erythroid lineage cells of p45-knockout mice, thereby masking the anticipated anemia. However, we failed to detect any greater failure in either erythroid or megakaryocytic cell development in Nrf2 plus p45 compound mutant mice as compared to with either individual homozygous mutation. These data suggest that p45 and Nrf2 may both be dispensable for hematopoietic cell development, and that other factors regulate erythroid- and megakaryocyte-specific gene expression through their required MAREs.
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PMID:Ablation of Nrf2 function does not increase the erythroid or megakaryocytic cell lineage dysfunction caused by p45 NF-E2 gene disruption. 953 17

GATA transcription factors are required for the differentiation of diverse cell types in several species. Recent evidence suggests that their biologic activities may be modulated through interaction with multitype zinc finger proteins, such as Friend of GATA-1 (FOG) and U-shaped (Ush). In cell culture, FOG cooperates with the hematopoietic transcription factor GATA-1 to promote erythroid and megakaryocytic differentiation. We show here that mice lacking FOG die during mid-embryonic development with severe anemia. FOG-/- erythroid cells display a marked, but partial, blockage of maturation, reminiscent of GATA-1- erythroid precursors. In contrast to GATA-1 deficiency, however, megakaryocytes fail to develop in the absence of FOG. Although the FOG-/- erythroid phenotype supports the proposed role of FOG as a GATA-1 cofactor in vivo, the latter finding points to a pivotal, GATA-1-independent requirement for FOG in megakaryocyte development from the bipotential erythroid/megakaryocytic progenitor. We speculate that FOG and other FOG-like proteins serve as complex cofactors that act through both GATA-dependent and GATA-independent mechanisms.
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PMID:Failure of megakaryopoiesis and arrested erythropoiesis in mice lacking the GATA-1 transcriptional cofactor FOG. 955 47

Megakaryocytic differentiation of progenitor cells was investigated in nine patients with low-risk myelodysplastic syndromes (MDS) (eight refractor anemia [RA] and one RA with ringed sideroblasts [RARS] and five patients with high-risk MDS (two RA with excess of blasts [RAEB] and three RAEB in transformation [RAEB-T]). Bone marrow-derived CD34+ cells were enriched to a purity of 87% +/- 2% (mean +/- SEM) and assayed in short-term suspension cultures in the presence of 10 ng/mL of PEGylated recombinant human megakaryocyte (MK) growth and development factor (PEG-rHuMGDF) and in addition to 50 ng/mL stem cell factor and 10 ng/mL interleukin-3. Cells of the megakaryocytic lineage were identified by flow cytometric analysis of CD42b (GP1b) and mature MKs by morphologic criteria. Transcription of c-mpl receptor-specific mRNA in the CD34+ cells of these patients was investigated by full-length reverse transcriptase polymerase chain reaction of the p form of c-mpl as well as of the alternative splice product c-mpl k. CD34+ cells from seven healthy bone marrow donors served as controls. Differentiation along the MK pathway was stimulated in five patients with RA. C-mpl mRNA was expressed in the CD34+ cells in all cases. In three low-risk patients the capacity for in vitro MK growth was absent or minimal even though mRNA for c-mpl receptor was detected in the CD34+ cells of this group as well. In patients with high-risk MDS, PEG-rHuMGDF stimulated in vitro MK growth from CD34+ cells in only one of five cases. As in the patients with low-risk MDS, c-mpl mRNA for both c-mpl p and c-mpl k splicing products was detected. These results indicate that the in vitro response to stimulation with c-mpl ligand discriminates between two groups of patients with low-risk MDS and that the observed defect in megakaryocytic development is unrelated to the level of c-mpl expression in both low-risk and high-risk MDS.
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PMID:Characterization of defective megakaryocytic development in patients with myelodysplastic syndromes. 1008


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