Pyknotic Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Pyknotic and links to relevant pages within the course.
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| What are Howell-Jolly Bodies? Howell-Jolly bodies are round, smooth, almost pyknotic, dark purple bodies ranging in size from 0.5 to 1.0 micron in diameter. Located eccentrically, usually only one Howell-Jolly body occurs in a mature or nucleated erythrocyte. Occasionally, two or more Howell-Jolly bodies per cell may be found. These DNA inclusions demonstrate a positive Feulgen reaction which is specific for DNA and RNA. | View Page |
| Howell-Jolly Body A Howell-Jolly body is present in a red cell in the center of this field. Notice that the color is deep purple, the shape is round and there is a smooth pyknotic appearance. | View Page |
| Which of the following statements characterize a reticulocyte? (Choose ALL of the correct answers) | View Page |
| Degenerate Neutrophils in EDTA blood When examining a slide made from an EDTA tube of normal blood, an occasional cell containing a round pyknotic nucleus and neutrophilic-appearing cytoplasm may be seen. Rare cells such as these do not indicate the presence of Pelger-Huet anomaly. | View Page |
| Hyposegmentation of Neutrophils Hyposegmented cells are neutrophils with fewer than three nuclear lobes. The nucleus may be round, peanut-shaped, band-shaped or bilobed. Since nuclear lobe development is abnormal, the chromatin structure often appears more mature than normal. It is sometimes very smooth, almost pyknotic. | View Page |
| Toxic Granulation Toxic granulation is manifested by the presence of large granules in the cytoplasm of segmented and band neutrophils in the peripheral blood. The color of these granules can range from dark purplish blue to an almost red appearance.
Toxic granules are azurophilic granules normally present in early myeloid forms, but which are not normally seen at the band and segmented stages of neutrophil maturation. These granules contain peroxidases and hydrolases.
Toxic granulation is seen in cases of severe infection, as a result of denatured proteins in rheumatoid arthritis or, less frequently, as a result of autophagocytosis. Infection is the most frequent cause of toxic granulation.
This type of granulation may be seen in cells which also contain Dohle bodies and/or vacuoles. Cells containing toxic granules may have decreased numbers of specific granules.
Cells containing only a few specific granules, with or without toxic granules, are said to be degranulated. The nucleus in degranulated cells may often be round-bilobed, smooth and pyknotic. This type of nucleus is the result of aging and will disintegrate soon.
Increased basophilia of azurophilic granules simulating toxic granules may occur in normal cells with prolonged staining time or decreased pH of the stain. | View Page |