Key Points. 1  Megaloblasts are large nucleated RBC precursors with noncondensed chromatin. 2  The most common causes of megaloblastic, macrocytic anemia are deficiency or defective utilization of vitamin B12 or folate. 3  Do CBC, RBC indices, reticulocyte count, and peripheral smear.
Wiktionary (0.00 / 0 votes) Rate this definition: vein (Noun). A blood vessel that transports blood from the capillaries back to the heart. vein (Noun). (used in plural veins) The entrails of a shrimp. vein (Noun). In leaves, a thickened portion of the leaf containing the vascular bundle. vein (Noun).
The word vein (meaning the tubes forming part of the blood circulation system) is often seen in the following terms: 1  vein blockage. 2  vein bruise. 3  vein burst. 4  vein collapse. 5  vein cream. 6  vein graft. 7  vein infection. 8  vein in leg. 9  vein removal. 10  vein thrombosis.