Pycnosis and necrosis

Mon Apr 11 09:21:52 EST 1994

In article <2o99sq$ia6 at> tkim at (Tae Hoon Kim) writes:
>Another question involving apoptosis and programmed cell death.
>I have come across the term "pycnosis" in reference to necrotic liver cells.
>From what I can gather this term refers to darkly staining nuclei and is
>different from chromatin marginalization, observed in apoptotic cells.
>In terms of gymnosperm phloem differentiation, sieve cells undergo
>"pycnotic nuclear degeneration." Do these observations in sieve cells and
>necrotic liver cells describe the same phenomenon?
>In angiosperm phloem differentiation, the term "chromatolysis" is used to
>describe nuclear degeneration in sieve cells. I have not able to look at
>actual micrographs, so I really don't know the actual differences between
>all these terms.
>Can anyone comment on these matters?
>Thank you!
>Tae Hoon Kim
>tkim at
Get any good pathology book and look up the term.  As far as I know,
pycnosis is an older term used by light microscopists.  Most of the
cells described as pycnotic probably were apoptotic, in that they
were condensed and with condensed rather than exploted nuclei, but
the term never had the precision that the Kerr-Wyllie description
of apoptosis has.  See also Schweichel and Merker, 1972 or Clarke,
--richard a lockshin

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