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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Murine blood was examined for circulating erythropoietic precursors. Blood mononuclear cells harvested using a slight modification of the Ficoll-Hypaque technique were cultured using the methylcellulose clonal cell culture technique. Only erythropoietic burst forming units (BFU-E) were present in the blood. Erythropoietin dose response studies revealed a progressive increment in the number of erythropoietic bursts up to a concentration of 4 U/ml of sheep plasma erythropoietin. A linear correlation existed between the numbers of nucleated cells plated and the erythropoietic bursts for both normal mice and mice with phenylhydrazine-induced (PHZ) anemia. No individual erythrocytic colonies were detected in cultures from blood taken before or after PHZ injections. These results suggest that erythrocytic colony-forming units (CFU-E) do not participate in the migration of erythropoietic precursors in mice.
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PMID:Erythropoietic precursors in murine blood. 87 6

Erythropoietin production was studied in 30-day-old and adult rats previously injected with pharmacological doses of isoproterenol. The animals were stimulated either by hypobaric hypoxia or by a combination of hypoxia and acute anemia. The erythropoietic activity of the plasma was measured by 59Fe incorporation in total circulating red blood cells of mice made polycythemic by chronic hypoxia. The results were converted to units of erythropoietin (IRP). A significant reduction of erythropoietin production was observed only in young rats. Our interpretation of the findings is that isoproterenol induced the differentiation of the salivary glands in the young animals hence reducing hormone production at the extrarenal (submandibular) level.
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PMID:Reduced extrarenal erythropoietin production in rats treated with isoproterenol. 87 9

The activity of hexokinase, glucose-6-phosphoric dehydrogenase, lactic dehydrogenase, succinic dehydrogenase, acid and alkaline phosphatases was determined in the rat kidney tissue with phenylhydrazine anemia and posttransfusion polycytemia. The blood supply of the cortical and medullary layers of the kidneys was studied at the same time. The purpose of this work was to ascertain possible connections between the changes in the activity of the enzymes under study with the renal erythropoietin producing function of the kidneys. The blood supply of the kidneys of rats with phenylhydrazine anemia was sharply decreased, but it was markedly elevated in case of posttransfusion polycytemia. There were no significant changes in the activity of the mentioned enzymes. These data suggest that the activity of the kidney enzymes is not a controlling factor in the renal erythropoietin production.
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PMID:[Activity of kidney tissue enzymes in phenylhydrazine anemia and post-transfusion polycythemia]. 89 Jan 28

The plasma erythropoietic activity of anephric mice and anephric mice without submandibular glands was compared. The erythropoietin production was stimulated by anemia (phenylhydrazine) and hypobaric hypoxia (0.4 atm). The activity was measured by the 59Fe incorporation in total circulating red blood cells in mice rendered polycythemic by hypoxia. The results were also calculated in units (IRP) of erythropoietin. The plasma erythropoietic activity of anephric mice was neutralized by antiserum against normal erythropoietin. Extrarenal erythropoietin production was significantly reduced in mice deprived of submandibular glands. These data indicate that this phenomenon is not restricted to the rat and support the concept that the submandibular glands are important extrarenal sources of erythropoietin.
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PMID:The role of the submandibular glands in extrarenal erythropoietin production in mice. 89 62

The purpose of this study was to further clarify the pathophysiology of anemia in malignancy. To accomplish this end a total of 210 normal or splenectomized rats with or without the solid form of Walker 256 carcinosarcoma was studied. In vivo studies demonstrated that in stage I cancer (tumor weight less than 10% of body weight) a slightly shortened red cell survival resulted in a mild degree of anemia. With increasing tumor size, 51Cr red cells mass decreased further, in spite of extramedullary erythropoiesis and a slightly increased incorporation transferrin-bound iron into red cells. Splenectomized rats with stage II cancer developed a more profound degree of anemia associated with a significantly decreased incorporation of 59Fe into red cells. Marrow cell culture studies demonstrated that heme synthesis in response to erythropoietin in stage I cancer was not significantly different from normal, but in rats with stage II cancer (tumor weight greater than 10% of body weight) heme synthesis in response to erythropoietin was markedly decreased. In vitro studies demonstrated that plasma erythropoietin levels were appropriately increased in most rats with transplanted malignancy. These studies indicate that bone marrow heme synthesis in response to erythropoietin is impaired in rats with the anemia of advanced malignancy.
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PMID:Pathogenesis of anemia in rats with Walker 256 carcinosarcoma. 89 4

The incidence of anemia after total gastrectomy has not received sufficient clinical emphasis. During a follow-up period averaging 32 months, postresectional anemia developed in seven of ten patients without evidence of malignant neoplasm; all but one of these patients had received parenterally administered cyanocobalamin. Despite low levels of circulating erythrocytes and proportionately increased erythropoietin levels, reticulocytosis was not evident. This observation suggests an uncharacterized failure of marrow erythyroid precursors. Multiple deficits in intake of constituents necessary for the production of erythrocytes were demonstrated. With the possible exception of iron, malabsorption of these constituents is not an important factor in the production of anemia. Postresectional anemia is multicausal, but is primarily nutritional. As total gastrectomy becomes more commonly employed in the treatment of nonmalignant conditions, recognition of the frequency and causes of postresectional anemia should assist both diagnostic anticipation and therapy.
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PMID:Postresectional anemia. A preventable complication of total gastrectomy. 94 93

The combination of aplastic anaemia and thymona was observed in a 49-year old woman. Concomitant with severe normochromic anaemia and reticulocytopenia was a cell-rich bone marrow smear in which erythropoietic precursors were almost absent. Immunological phenomena could not be demonstrated. The erythropoietin level was maximally increased. Pathological anatomy typically revealed a predominantly spindle-cell thymonal with only minor capsular invasion.
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PMID:[Aplastic anaemia and thymonal]. 95 99

The diminished erythropoiesis in the anemia of chronic renal disease has been attributed to three possible factors: (1) decreased erythropoietin production, (2) inhibition of erythropoietin activity, and (3) decreased bone marrow response to erythropoietin. In this report we isolated and evaluated these parameters in 19 patients with chronic renal disease, nine patients with iron-deficiency anemia, and seven control subjects. The results in patients with chronic renal failure were as follows: (1) erythropoietin enhanced heme synthesis in bone marrow cell cultures by 88 +/- 12 per cent in renal failure, as compared to 65 +/- 7 per cent in the control group; (2) plasma erythropoietin activity did not increase appropriately for the degree of anemia; and (3) erythropoietin inhibitor activity in renal failure was not greater than in a control group. In conclusion, the relative failure of erythropoiesis in chronic renal disease appears to be due primarily to decreased production of erythropoietin and not to diminished marrow response to erythropoietin.
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PMID:Erythropoiesis in chronic renal disease. 96 7

An erythropoietic inhibitor was detected in the serum of a patient with refractory anemia. Using an in vitro heme synthesis method, the patient's serum produced tenfold inhibition of erythropoietin-stimulated radioactive iron (Fe59) incorporation into heme of normal human marrow at 72 hours, as compared with AB serum. In a separate experiment the patient's serum produced threefold inhibition, whereas immunoglobulin G (IgG) prepared from the same serum sample produced 12-fold inhibition. To identify the site of action of the inhibitor, serum was tested in a cell culture system whereby human marrow cells, grown in a plasma clot, respond to exogenous erythropoietin with the appearance of nucleated erythroid colonies. Each colony arises from a committed erythroid progenitor. The patient's serum produced a two- or tenfold reduction in the number of colonies from normal human marrow. The effect was also demonstrated on autologous marrow obtained when the patient was in "partial clinical remission". Serum samples obtained at various times during the course of the patient's illness all demonstrated a suppressive effect on colony growth. All serums were heat-inactivated, and total hemolytic complement could not be detected in either culture system. It is concluded that the anemia is due to an inhibitor, probably of IgG class, that acts on the erythroid progenitor cell. The absence of heat-labile complement components in the culture systems suggests that the mechanism is not due to immune cytolysis.
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PMID:A complement independent erythropoietic inhibitor acting on the progenitor cell in refractory anemia. 97 51

Peripheral blood lymphocytes from six patients with congenital hypoplastic anemia suppressed erythroid cell formation by normal human bone marrow cells in response to erythropoietin in vitro. The results suggest that the anemia in these children has an immunologic basis.
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PMID:Diamond-Blackfan syndrome: lymphocyte-mediated suppression of erythropoiesis. 98 86


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