The paradox of Ferrata and the fate of the extruded red cell nucleus: two problems concerning erythropoiesis in the human.
A critical analysis of the present erythropoietic pathway reveals two problems which require resolving. One is the paradox of the basophilic erythroblast, and the other is the fate of the extruded red cell nucleus. The problems can be overcome if erythropoiesis is looked at differently, and the orthochromatic normoblast considered to arise directly from a denuded stem cell nucleus as has been previously suggested. The orthochromatic normoblast extrudes its nucleus leaving behind a reticulocyte. The extruded but functionally impaired nucleus of the orthochromatic normoblast then gives rise to a polychromatic normoblast, a defective cell. The poorly made cytoplasm of the polychromatic normoblast is shed and its nucleus, now non-functional, undergoes complete dissolution into an aggregate of ultrafine particles. The theory has the advantage that the fate of the extruded red cell nucleus can be explained without having to introduce phagocytosis by macrophages and all the immunological difficulties which this entails. The new pathway does away with the basophilic erythroblast as a haemoglobin-producing cell, and it is argued that the cell instead is a ferritin storage cell, and that erythropoiesis is the result of two separate but interdependent pathways, a ferritin storage pathway and a haemoglobin production pathway. Evidence is put forward to support the new pathways.
Drummond
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D001695:Biology / Q000266:history; D002467:Cell Nucleus / Q000502:physiology* / Q000648:ultrastructure; D004900:Erythroblasts / Q000502:physiology / Q000648:ultrastructure*; D004912:Erythrocytes / Q000502:physiology* / Q000648:ultrastructure*; D004920:Erythropoiesis; D006412:Hematopoietic Stem Cells / Q000502:physiology / Q000648:ultrastructure; D049673:History, 20th Century; D006801:Humans; D007558:Italy; D008954:Models, Biological