Hematopathology and Coagulation Self-Assessment and Board Review Ebook PDF download
Hematopathology and Coagulation Self-Assessment and Board Review Ebook PDF download involves maturation of erythroblasts to red cells. The stages in between include basophilic normoblast (early normoblast), polychromatic normoblast (intermediate normoblast), orthochromatic normoblast (late normoblast) and reticulocyte. The erythropoietic elements are typically seen as clusters (or islands) surrounding macrophages. The macrophages provide nutrition to the developing and to the maturing cells and are referred to as nurse cells. They also phagocytize defective erythropoietic precursors. Erythropoiesis occurs close to sinusoids, not in the paratrabecular areas.
Hematopathology and Coagulation Self-Assessment and Board Review Ebook PDF download Proerythroblasts are large cells with deep blue cytoplasm and a large nucleus. A Golgi hof may be apparent. The nuclei have nucleoli. Nucleoli are not apparent in subsequent cells. The nuclei of the normoblasts become more and more clumped and in late normoblasts the nuclei are dark and pyknotic. The cytoplasm of the normoblasts changes from blue (in early normoblasts) to bluish grey (in intermediate normoblasts) to orange- pink tinge (in late normoblasts). These changes denote increased amount of hemoglobin in the cytoplasm. Once the nucleus is extruded the cell is known as a reticulocyte, which is converted to a mature red cell in approximately three d a y s . B CD 71 is the transferrin receptor and is present in erythroid precursors. It is not present in mature red cells. CD34 is an immature marker and not confined to erythroid precursors. It is thus present in myeloblasts and lymphoblasts. CD41 is platelet glycoprotein IIb and CD61 is platelet glycoprotein IIIa. A Heme biosynthesis starts with the formation of δ aminolevulinic acid from glycine and succinyl CoA, which is the rate- limiting step.
Hematopathology and Coagulation Self-Assessment and Board Review Ebook PDF download takes place in the mitochondrion. The next few steps of heme biosynthesis takes place in the cytoplasm. T he last step, which is the formation of heme from protoporphyrin IX (addition of Fe with the help of the enzyme ferrochelatase), again takes place in the mitochondrion. Heme then moves to the cytoplasm and combines with the globin chains to form hemoglobin.
When there is iron deficiency, then the enzyme ferrochelatase substitutes zinc in place of iron. Zinc protoporphyrin is thus formed. In iron deficiency, levels of zinc protoporphyrin are increased.