Plasma Erythropoietic Activity Research Articles

Plasma erythropoietic activity in healthy children and in children with iron-deficiency anemia

The level of plasma erythropoietic activity was determined in healthy and iron deficiency anemia children by bioassay in vitro. The erythropoietic activity in healthy children was 13.6 +/- 2.9 (5.0-24.8) mU/ml and the lowest activity was in two month (6.3 +/- 0.7) and three month (6.9 +/- 1.4) mU/ml healthy children. The erythropoietic activity was increased from 40.5 to 715.0 mU/ml in iron deficiency anemia children and its level distinctly depends on anemia stage and iron deficiency. From this study we suggest, that erythropoietin is produced in response of anemia. The results also demonstrate the necessity of erythropoietin treatment in iron deficiency anemia in early infants.

Partial inhibition of hypoxia-induced erythropoietin production by cholinergic blockade in the dog (39866).

SummaryAnesthetized dogs exposed to hypoxic hypoxia showed elevated plasma erythropoietic activity by 6 hr. This activity was significantly decreased by atropine pre-treatment. Methylatropine, a peripheral-acting analog of atropine, was equally effective in reducing the erythropoietic response. Neither atropine nor methylatropine, at the doses employed, appeared to exert their effect through blockade at the autonomic ganglia. These studies suggest that the erythropoietic response to short-term hypoxia in the dog involves a peripheral, cholinergic-ally mediated event, perhaps within the kidney itself.We are very grateful to Mr. Rene Stiaes and Mr. Jesse Brookins for their excellent technical assistance.

Effect of hyperbaric oxygen therapy on erythropoiesis in the recovery period after hemorhagic collapse

Hyperbaric oxygenation (2 atm O2, 40 min) accelerates the restoration of the normal cell count and hemoglobin concentration in the peripheral blood of albino rats after acute blood loss (2.8% of body weight). In the bone marrow, coupled with increased proliferative activity of erythroblasts and normoblasts, intensive maturation of hemoglobin-containing forms was observed. The maximal level of plasma erythropoietic activity of the anemized animals was found on the first and tenth days after blood loss. The serum possessed erythropoiesisinhibiting properties on the 15th day. It is postulated that hyperbaric oxygenation after acute blood loss potentiates the stimulation of erythropoiesis induced by erythropoietin.

Plasma erythropoietic activity in patients on chronic dialysis with or without kidneys.

Plasma erythropoietic activity in patients on chronic dialysis with or without kidneys.

Erythropoietic effects of 5-hydroxytryptamine.

SummarySerotonin (5 -hydroxytrypta-mine) was found to produce a significant increase in radioiron incorporation in red cells of polycythemic mice. A linear dose-response relationship is reported. Anti-ESF produced a significant inhibition of the erythropoietic effects of 5-HT in polycythemic mice. However, residual erythropoietic activity was still seen even in the presence of antiserum to erythropoietin suggesting a secondary erythropoietic effect which is not erythropoietin dependent. Intrarenal infusions of 5-HT into dogs was found to produce a significant elevation in plasma erythropoietic activity.

The Effects of General Hypoxic Hypoxia and Renal Ischemia on Erythropoietin Production

AbstractThere is considerable evidence in literature concerning the stimulation of erythropoietin production in response to hypoxic hypoxia, as induced by exposure to simulated altitude (Stohlman and Brecher, 1957 and 1959; Jacobson et al., 1959; Gordon et al., 1959; Mirand et al., 1959). The increased erythropoietin in plasma is assumed to be responsible for the well-known acceleration of erythropoiesis under conditions of chronic and intermittent acute hypoxia. Some years ago, Grant (1951) and Terzioglu et al. (1955) demonstrated that the erythropoietic stimulation in chemoreceptor-denervated rabbits intermittently exposed to pressures of 400-410 mm Hg, for a total of 120-150 hours, was of a far greater magnitude than in the controls similarly treated. In order to investigate whether the greater erythropoietic response of the chemoreceptor-denervated animals was due to an increase in erythropoietin production, we undertook the present study where the plasma erythropoietic activity of the control and che...

Development of response to erythropoietin and repletion of the stem cell compartment after irradiation.

Abstract Experiments involving repression of erythropoiesis by plethora, its partial restoration by erythropoietin, and assay of plasma erythropoietic activity provided evidence that erythropoietin was present in the plasma of mice after partial-body irradiation (850 R L.S.). Erythroblast counts and femoral uptake of 59 Fe disclosed that erythro-poietin-responsive cells increased in shielded femoral marrow initially but diminished to subnormal levels after 5 days. In contrast, replicating cells in the spleen were not responsive to erythropoietin until 5 days after irradiation, when increasing erythroblast counts and the splenic uptake of 59 Fe revealed their presence. Up to a point, the greater the number of endogenous stem cells permitted to emigrate from a shielded femur and colonize the spleen, the earlier will be the recovery of splenic erythropoiesis. The onset of splenic erythropoiesis was more closely related to the duration of leg-shielding and the mean splenic weight than it was to time elapsed after irradiation. We suggest that the new colonies of primitive hemopoietic cells must attain a certain critical mass before they develop the capacity to respond to erythropoietin by differentiation.

Hormonal control of erythropoiesis during pregnancy in the mouse.

Summary. Increased plasma erythropoietic activity was observed during pregnancy in the mouse, first appearing on the 5th day. Reticulocytosis, increase of red‐cell volume, decrease of plasma iron and increase of the total iron binding capacity appeared on the 10th day. The major increase of red‐cell volume and plasma volume occurred during late pregnancy as the reticulocytes and plasma iron progressively decreased. Suppression of endogenous erythropoietin production in pregnant mice by hyperoxia did not completely abolish either plasma erythropoietic activity or the rise of the red‐cell volume observed in unexposed pregnant mice. Placental lactogen was found to have some erythropoietic activity and increased the plasma volume. Ovarian hormones were erythropoietically ineffective and, in fact, oestrogen appeared to inhibit the activity of placental lactogen.

Erythopoiesis during pregnancy and lactation in the mouse. II. Role of erythropoietin.

Suppression of erythropoietin secretion in lactating and normal female mice by 60% oxygen decreased their RCV and reticulocyte output and abolished plasma erythropoietic activity. In normal mice and in nonlactating postpartum mice, administration of prolactin resulted in an increase of RCV and of PV to values equivalent to those of 15-day postpartum lactating mice. Administration of prolactin to lactating mice and to normal female mice concurrently exposed to hyperoxia prevented the decrease of RCV and of PV which resulted from exposure to hyperoxia alone. The data indicate that in mice, the prolactin preparation used acted as an erythropoietic stimulant and caused a plasma hypervolemia which was not related to the action of erythropoietin.

Erythropoiesis during pregnancy and lactation. I. Effect of various hormones on erythropoiesis during lactation.

SummaryRCV and plasma erythropoietic activity were significantly increased throughout lactation in the mouse as compared with normal female mice and with nonlactating postpartum mice. The RCV decreased and plasma erythropoietic activity disappeared rapidly in nonlactating mice. Prolactin stimulated erythropoiesis in postpartum nonlactating mice and polycythemic mice while adrenal steroids and thyroid hormone were ineffective.

POLYCYTHAEMIA WITH METASTASES FROM CARCINOMA OF THE KIDNEY

SUMMARY A case of polycythemia associated with metastases from a renal carcinoma removed eighteen years previously is described. Assay of erythropoietic activity in plasma, liver, spleen, bone marrow, and metastases in lung and brain showed increased activity, whilst the remaining normal kidney tissue was within the normal range.

Erythropoietic activity in plasma and urine of dogs after bleeding.

SummaryActive erythropoietic factor is demonstrated in plasma and urine of bled dogs. A very striking erythropoietic factor response is obtained when severe anemia is produced. Activity is partially destroyed by boiling and by prolonged storage in freezer.

Studies on Erythropoiesis. XI. Reticulocyte Response of Transfusion-Induced Polycythemic Mice to Anemic Plasma from Nephrectomized Mice and to Plasma from Nephrectomized Rats Exposed to Low Oxygen

Abstract Mice with transfusion-induced polycythemia have been used to assay erythropoietic activity in plasma derived from mice and rats subjected to various stimuli and experimental procedures. 1. Anemic, anoxic, or cobalt mouse plasma increased erythropoiesis from the zero baseline to about the normal range after four 0.5 cc. injections. No significant effect is observed from the same number of injections of normal rat or mouse plasma or normal saline. Similarly, plasma from rats starved for 4 days had no erythropoietic activity, but erythropoietic activity was present in the plasma of pregnant mice during the last trimester of pregnancy. 2. Plasma from mice made anemic by phenylhydrazine and then subjected to bilateral nephrectomy contained slight erythropoietic activity (less than 0.2 per cent reticulocytes). The plasma of sham-operated anemic animals had considerably more erythropoietic activity (2.0 per cent). The plasma was collected for assay 10 hours after the operative procedures. 3. Plasma from nephrectomized rats exposed to hypoxic anoxia for 8, 16, or 24 hours, had slight erythropoietic activity when measured by the peripheral reticulocyte response of the recipients (0.18, 0.11, and 0.00 per cent reticulocutes, respectively). The same plasma had no erythropoietic activity when judged by the Fe59 red cell incorporation response in starved rats. Plasma from rats subjected to bilateral ureter ligation and similarly exposed had an erythropoietic activity (0.7, 1.38, and 1.26 per cent reticulocytes, respectively), comparable with that of the plasma from normal rats exposed to hypoxic anoxia (0.9, 1.71, and 1.78 per cent, respectively). The low and inconstant erythropoietic activity in the plasma of nephrectomized mice and rats subjected to anemic or hypoxic anoxia is more or less comparable with the response occasionally produced by normal plasma. We are, therefore, disinclined to consider the data as evidence against the renal origin of erythropoietins, but the alternative possibilities are discussed.

Concentration of highly potent erythropoietic activity from urine of anemic patients.

Summary1) Some patients with aplastic anemia had exceptionally high levels of erythropoietic activity in plasma. The urine of these patients was assayed, and in some it was equally as potent as the plasma. As little as 1 ml daily for 14 days of untreated urine from such a patient produced a significant polycythemia in normal adult rats. When a concentrate of such urine, prepared by ultrafiltration, was injected at a dose equivalent to 30 ml daily for 14 days into normal adult rats, a polycythemia was produced which exceeded that resulting from exposure to a simulated altitude of 15.000 feet for the same period of time. 2) The high potency of such urine has allowed its assay in normal rats. This finding, together with the easy availability of urine and the efficiency of ultrafiltration as a method for preparing concentrates of urinary erythropoietic activity, should allow for a more rapid investigation of the chemistry and biology of this factor.