We evaluated the quantitative value of a simple model of erythropoiesis, based on the basic assumptions that the red blood cell (RBC) mass determines erythropoietin (Epo) production, which in turn stimulates erythropoietic activity. The RBC mass was quantitated by direct isotopic measurement (RCM), Epo production by serum Epo levels, and erythropoiesis by the ferrokinetic measurement of the ery...

This volume contains the proceedings of a conference on erythropoiesis held at Tel Aviv University from July 27-29, 1970. Twenty-seven papers are listed under six headings: "Fetal and Neonatal Erythropoiesis," "Assay of Erythropoietin," "Androgens and Erythropoiesis," "Mechanism of Action of Erythropoietin," "Regulation of Erythropoiesis," and "Production of Erythropoietin: Renal and Extrarenal...

Two patients with chronic myelocytic leukemia who developed an erythroblastic rather than a myeloblastic phase were studied with respect to whether or not the megaloblastic erythropoiesis was subject to normal control mechanisms. After transfusion, no significant reduction was observed in the percentage of nucleated erythroid precursors or of proerythroblasts in marrow or in blood reticulocytes...

It is well known that avian yolk sac is involved in both primitive and definitive erythropoiesis during embryonic development. Definitive erythropoiesis is first detected at about 4-5 days incubation and its maximum activity is reached between day 10 and 15 of incubation, ending between days 18 and 20 of incubation. We confirmed the definitive erythropoietic foci in the chicken yolk sac through...

Erythropoietin and its receptor are required for definitive erythropoiesis and maturation of erythroid progenitor cells. Mice lacking the erythropoietin receptor exhibit severe anemia and die at about embryonic day 13.5. This phenotype can be rescued by the human erythropoietin receptor transgene. Animals expressing only the human erythropoietin receptor survived through adulthood with normal h...

The relationship between serum hepcidin, a key regulator of body iron homeostasis, and erythropoiesis was investigated before and after stem cell transplantation in 31 patients with hematopoietic malignancies. Serum hepcidin-25 was monitored using a liquid chromatography-tandem mass spectrometry-based assay system. Other iron- and erythropoiesis-related parameters and known hepcidin regulators,...

Congenital dyserythropoietic anemia (CDA) is a rare group of red blood cell disorders characterized by ineffective erythropoiesis and increased iron absorption. To determine whether growth differentation factor 15 (GDF15) hyper-expression is associated with the ineffective erythropoiesis and iron-loading complications of CDA type I (CDA I), GDF15 levels and other markers of erythropoiesis and i...

Recent advances in experimental hematology have provided new insight into the physiology of erythropoiesis. Techniques are now available for cloning in vitro the various hematopoietic progenitor cells of both animals and man. Erythropoietin has been purified and a radioimmunoassay for the hormone has been described. In this paper, we discuss the physiology of erythropoietin and erythropoiesis w...

Although most circulating iron in blood plasma is destined for erythropoiesis, the mechanisms by which erythropoietic demand modulates the iron supply ("erythroid regulators") remain largely unknown. Iron absorption, plasma iron concentrations, and tissue iron distribution are tightly controlled by the liver-produced hormone hepcidin. During the last decade, much progress has been made in eluci...

Six patients had primary sideroblastic erythropoiesis together with a haemoglobin concentration of 12.0 g/dl or higher. In four cases this was associated with macrocytosis. Other abnormalities included failure of erythroid progenitor growth from peripheral blood in three cases and occasional dysplastic appearances in neutrophils and megakaryocytes. Sideroblastic erythropoiesis seems to be an ea...