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)

Lactoperoxidase-catalysed radio-iodination was used to compare the surface proteins on red cells from Plasmodium yoelii-infected with normal BALB/c mice. The profile of radio-iodinated proteins separated by SDS-polyacrylamide gel electrophoresis was different for infected blood of similar parasitaemia from mice inoculated with different doses of the parasite. Inoculation with different doses of the parasite. Inoculation with the lower dose resulted in the appearance of a major radio-iodinated protein of apparent molecular weight (Mr) 76 000 which was labelled to a similar extent on uninfected red cells from infected blood and purified multinucleate infected cells. Several minor radio-iodinated bands, with identical mobilities to the minor bands on normal BALB/c erythrocytes, were also present on red cells from this infected blood. In contrast, the higher inoculation dose produced changes in the minor labelled bands, and the band with Mr of 76 000 was absent. In this case, the minor radio-iodinated proteins of the normal BALB/c erythrocyte (with Mr of 65 000, 57 000, 48 000, 38 000 and 32 000) were replaced by a series of bands with Mr of 60 000, 50 000, 43 000 and 28 000 on both uninfected and infected red cells. These differences with inoculation dose may be related to the different duration of these infections, the development of anaemia and the extent of pathological changes at the erythrocyte surface. P. yoelii infection caused a marked loss in periodate-dependent labelling of sialoglycoproteins on most, if not all, red cells in infected blood. There was also a large decrease in galactose oxidase-dependent glycoprotein labelling with or without neuraminidase treatment. These changes in the carbohydrate groups on red cell membrane glycoproteins may be linked to the excessive loss of both uninfected and infected red cells during some malaria infections.
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PMID:Characterization of surface proteins and glycoproteins on red blood cells from mice infected with haemosporidia: Plasmodium yoelii infections of BALB/c mice. 744 94

Erythropoietin, a glycoprotein, is synthesized mainly in the kidney. With the destruction of renal tissue, erythropoietin production decreases; this is a major factor in the development of anemia in patients with renal failure. For about ten years now, recombinant human erythropoietin has been available for the treatment of renal anemia. All patients with renal insufficiency, independent of their plan for future renal replacement therapy, may benefit from erythropoietin. At what extent of anemia erythropoietin therapy should be started is still discussed and is certainly dependent on the degree of the patient's impairment by his anemia. Before beginning a therapy with erythropoietin, other forms of anemia observed in patients with renal failure, i.e. mainly iron deficiency, have to be excluded. A strict monitoring of hematocrit during treatment with erythropoietin is mandatory. Hypertension, seizures and cardiovascular complications have been observed with overdosing of erythropoietin. Special emphasis of this review is therefore put on the discussion of the dynamics of the erythropoietin-red cell system.
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PMID:[Erythropoietin, a milestone in the history of nephrology]. 748 78

Epoetin alfa is a recombinant form of erythropoietin, a glycoprotein hormone which stimulates red blood cell production by stimulating the activity of erythroid progenitor cells. This review discusses the use of the drug in the management of anaemia in diseases often associated with advancing age [renal failure, cancer, rheumatoid arthritis (RA) and other chronic diseases, and the myelodysplastic syndromes (MDS)] and in surgical patients. Intravenous and subcutaneous therapy with epoetin alfa raises haematocrit and haemoglobin levels, and reduces transfusion requirements, in anaemic patients with end-stage renal failure undergoing haemodialysis or peritoneal dialysis. The drug is also effective in the correction of anaemia in patients with chronic renal failure not yet requiring dialysis and does not appear to affect renal haemodynamics adversely or to precipitate the onset of end-stage renal failure. Response rates of 32 to 82% with epoetin alfa therapy have been reported in patients with anaemia associated with cancer or cytotoxic chemotherapy. Limited data in patients with anaemia associated with RA show correction of anaemia after epoetin alfa treatment. Response rates to the drug of 0 to 56% have been noted in patients with MDS. Epoetin alfa also reduces anaemia, increases the capacity for autologous blood donation and reduces the need for allogeneic blood transfusion in patients scheduled to undergo surgery. Hypertension occurs in 30 to 35% of patients with end-stage renal failure who receive epoetin alfa, but this can be managed successfully with correction of fluid status and antihypertensive medication where necessary, and is minimised by avoiding rapid increases in haematocrit. Although vascular access thrombosis has not been conclusively linked to therapy with the drug, increased heparinisation may be required when it is administered to patients on haemodialysis. Epoetin alfa does not appear to exert any direct cerebrovascular adverse effects. Thus, epoetin alfa is a well established and effective therapy for the management of anaemia associated with renal failure. It also improves haematocrit and quality of life in patients with anaemia associated with cancer or chemotherapy. Epoetin alfa increases the capacity for blood donation and reduces the decrease in haematocrit seen in patients donating autologous blood prior to surgery. It also reduces, but may not eliminate, the need for allogeneic blood transfusion.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Epoetin alfa. A review of its clinical efficacy in the management of anaemia associated with renal failure and chronic disease and its use in surgical patients. 757 84

Erythropoietin, the glycoprotein which regulates erythropoiesis is unique amongst the hematopoietic growth factors since it is the only one which behaves like a hormone. Produced primarily in the kidneys in adults, erythropoietin interacts with erythroid precursors in the marrow to increase red cell production. Because erythropoietin behaves like a hormone, measurements of erythropoietin in the serum have proved useful in determining when production of this hormone is inadequate. Tissue hypoxia is the only physiologic stimulus for erythropoietin production and thus, with anemia, serum erythropoietin levels should be increased. Assuming normal marrow function and adequate nutrient supplies, when anemia is associated with a low serum erythropoietin level, it can be concluded that the anemia is in part due to erythropoietin lack and should be correctable by administration of erythropoietin. As a corollary, a high serum erythropoietin level (greater than 500 mU/ml) in the presence of anemia suggests that there is end organ failure, and erythropoietin therapy is not likely to be useful.
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PMID:Serum immunoreactive erythropoietin in health and disease. 765 13

Activation of the TAL1 (or SCL) gene, originally identified through its involvement by a recurrent chromosomal translocation, is the most frequent molecular lesion recognized in T-cell acute lymphoblastic leukemia. The protein products of this gene contain the basic-helix-loop-helix motif characteristic of a large family of transcription factors that bind to the canonical DNA sequence CANNTG as protein heterodimers. TAL1 expression by erythroid cells in vivo and in chemical-induced erythroleukemia cell lines in vivo suggested the gene might regulate aspects of erythroid differentiation. Since the terminal events of erythropoiesis are controlled by the glycoprotein hormone erythropoietin (Epo), we investigated whether the expression or activity of the TAL1 gene and its protein products were affected by Epo in splenic erythroblasts from mice infected with an anemia-inducing strain of Friend virus (FVA cells). Epo elicited a rapid, dose-related increase in TAL1 mRNA by increasing transcription of the gene and stabilizing one of its mRNAs. An Epo-inducible TAL1 DNA binding activity was identified in FVA cell nuclear extracts that subsequently decayed despite accumulating mRNA and protein. Induction of DNA binding activity was associated temporally with Epo-induced phosphorylation of nuclear TAL1 protein. These results indicate that Epo acts at both transcriptional and posttranscriptional levels on the TAL1 locus in Friend virus-induced erythroblasts and establish a link between Epo signaling mechanisms and a member of a family of transcription factors involved in the differentiation of diverse cell lineages.
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PMID:Erythropoietin stimulates transcription of the TAL1/SCL gene and phosphorylation of its protein products. 774 99

Erythropoietin (Epo) is a glycoprotein hormone responsible for the control of the proliferation and differentiation of cells of erythroid lineage. Recombinant erythropoietin (rHuEpo) is widely used as a pharmacological agent for the treatment of the anaemia of renal failure. Efficacy of rHuEpo and its superiority over blood transfusions have been proven in large multicentre trials. The most important side-effect of the therapy is the increase of BP which is observed in approximately 30-35% of dialysis patients receiving rHuEpo. It appears that the haemodynamic resetting that occurs with partial correction of anaemia may be inappropriate resulting in an altered vascular resistance in relation to the cardiac output. This is in turn due to the combination of increased blood viscosity and loss of hypoxic vasodilatation. Both these factors, however, cannot account completely for the rise in vascular resistance, and therefore the possibility of a direct and/or hormonally-mediated vasopressor effect of rHuEpo has recently been raised. Moreover, scarce information exists on the possible involvement of endogenous erythropoietin in the pathogenesis of arterial hypertension and haematological disturbances observed in primary and some secondary forms of hypertension.
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PMID:Erythropoietin and hypertension. 775 79

Normal rat kidney cells, non-productively infected with the anaemia-inducing variant of Friend spleen focus-forming virus (F-SFFVA), were metabolically labelled with [2-3H]mannose. The primary translation product of the viral envelope gene (env), representing a glycoprotein with an apparent molecular M(r) of 55,000 (gp55), was isolated from cell lysates by immunoaffinity chromatography and purified by preparative SDS/PAGE. Radiolabelled oligosaccharides, released from tryptic glycopeptides by treatment with endo-beta-N-acetylglucosaminidase H, were characterized chromatographically, by enzymic digestion and by acetolysis. The results revealed that F-SFFVA gp55 obtained from this source carried predominantly oligomannose type sugar chains with five to nine mannoses. As a characteristic feature, glycans with seven to nine mannoses contained, in part, an additional glucose residue. Although the amount of glucosylated species found was higher in F-SFFVA gp55 (about 25% of total endo-H-sensitive oligosaccharides) than in gp55 of the corresponding polycythaemia-inducing variant (F-SFFVP, 16.3%), the overall glycosylation pattern of the F-SFFVA env product closely resembled that of F-SFFVP gp55 [Strube et al. (1988) J Biol Chem 263:3762-71]. Hence, our results demonstrate that the different intracellular processing and transport of the primary F-SFFVA env product cannot be attributed to aberrant trimming of its oligomannose type glycans.
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PMID:Glycosylation of glycoprotein 55 encoded by the anaemia-inducing strain of Friend spleen focus-forming virus. 780 3

The glycoprotein hormone erythropoietin is an essential survival and growth factor for the erythrocytic progenitors in the bone marrow. Its peptide sequence of 165 amino acids is stabilized by 4 carbohydrate side chains (total molecular mass 30 kDa, 60% protein). Erythropoietin is synthesized mainly in the kidney. Its formation increases greatly in response to hypoxia. The mechanism by which lack of oxygen induces erythropoietin gene expression is only partly understood. Erythropoietin deficiency is the primary cause of the anemia in chronic renal failure. Erythropoietin production is lowered in severe acidosis and in inflammatory states. Genetical engineering has enabled the isolation of the human erythropoietin gene and its in vitro expression in mammalian cell cultures. Recombinant human erythropoietin has been approved to be an efficient and safe drug for treatment of renal anemia. This paper reviews some of the recent advances in the understanding of the biology of erythropoietin with respect to its possible application as an alternative to blood transfusion in surgical patients.
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PMID:Biology of erythropoietin. 795 Jan 69

Congenital dyserythropoietic anaemia type II (CDA II) is a rare genetic anaemia in humans, inherited in an autosomally recessive mode. CDA II is also called HEMPAS as this disease is characterized by hereditary erythroblastic multinuclearity with positive acidified serum lysis test. Analyses of CDA II erythrocyte membranes showed that the band 3 glycoprotein is underglycosylated. An aberrant glycosylation pattern is seen in the polylactosamine carbohydrates which are normally attached to the band 3 and band 4.5 glycoproteins. The polylactosamines are, however, accumulated in the form of glycolipids. Therefore a genetic factor in CDA II appears to block the glycosylation of protein acceptors and shift these carbohydrates to the lipid acceptors. Structural analysis of CDA II band 3 carbohydrates identified truncated hybrid-type oligosaccharides and suggests that the Golgi glycosylation enzyme(s), alpha-mannosidase II or N-acetylglycosaminyltransferase II is defective in CDA II. By using a cDNA probe for alpha-mannosidase II, one CDA II case has been identified as being defective in the gene encoding alpha-mannosidase II. At present, it is not clear whether CDA II is a genetically heterogenous collection of glycosylation deficiencies, or genetically homogenous but apparently heterogenous in phenotype expression. Freeze-fracture electron microscopy and immunoelectron microscopy revealed that the band 3 glycoproteins are clustered in CDA II erythrocyte membranes. The abnormal distribution of band 3 might cause an unstable membrane organization. In CDA II erythroblasts, the membrane proteins might also be underglycosylated and abnormally distributed. When normal erythroblasts were cultured in vitro in the presence of swainsonine (alpha-mannosidase inhibitor) the erythroblasts became multinucleared. It is, therefore, quite possible that the enzymic defect of alpha-mannosidase II could cause various morphological anomalies including multinuclearity. Because the genes encoding glycosylation enzymes are housekeeping genes, the enzyme defect of CDA II is not restricted to erythroid cells and there is also an abnormal glycosylation of hepatocyte glycoproteins. On the other hand, there are many types of cells and tissues which appear not to be affected by the CDA II defect. A mechanism for the erythroid-specific manifestation of CDA II and its tissue specificity are also discussed.
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PMID:Congenital dyserythropoietic anaemia type II (HEMPAS) and its molecular basis. 804 36

Erythropoietin (EPO) is a glycoprotein produced primarily by the kidney in response to tissue hypoxia, and is the principal factor regulating red blood cell production. It stimulates erythroid precursors in the bone marrow to proliferate and mature into morphologically identifiable red blood cells. This hormone acts by binding to specific high-affinity receptor on erythroid precursors. Failure to produce adequate quantities of EPO leads to severe anemia, a situation most often encountered in patients with end stage renal disease. With the application of recombinant DNA technology, the gene for this hormone has been molecularly cloned, sequenced and expressed in a biologically active form in mammalian cells. The recombinant EPO has been demonstrated to correct anemia in patients with severe end stage renal disease and alleviate their transfusion requirements. It has also been studied for anemia associated with HIV infection/zidovudine therapy, in cancer, rheumatoid arthritis, and prematurity. In addition it has been studied as a facilitator of autologous blood predeposit in patients scheduled for elective surgery and as a perisurgical adjuvant to hasten hematologic recovery and possibly avoid the need for homologous transfusion after elective surgery. When administered with the current guidelines EPO appears to be safe drug with favorable risk/benefit ratio.
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PMID:[Clinical applications of erythropoietin]. 806 96


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