Thanks Barry, will keep these points in mind.

Julee

-----Original Message-----
From: Barry R Rittman [mailto:Barry.R.Rittman@uth.tmc.edu] 
Sent: Tuesday, July 08, 2003 10:49 PM
To: histology
Subject: RE: deplasticizing MMA sections


Julee

I think that the discussion about thickness of plastic sections raises
an important point, namely how to get the information you want from
these sections. It is technically difficult and requires considerable
skill and time to consistently produce very thin plastic sections. The
perception of course is that resolution dictates "the thinner the
section the better". However, thicker sections (routine ground or
plastic) have an important place in histology. As has been pointed out,
the surface of the sections can be etched and stained. Using incident
light microscopy the upper few microns can be used to form the image.
As reflected light generally only penetrates a few microns into hard
tissues,  you can have your cake and eat it as only the upper few
microns are used to form the image. Many studies in histology have used
thick sections, stained the upper few microns and then once the
information is recorded have repeated polishing the surface, staining
upper layers and so on. This is similar to the advantage of serial
sections. 

Thick sections can also be examined either unstained or stained using
other types of microscopy, optically sectioned  e.g. Differential
Interference Contrast, Hoffman Modulation, Confocal, Deconvolution
Microscopy etc. 
Thick sections, whether ground or paraffin, while generally not
providing the same degree of resolution,  can be very useful in
providing a better overall concept of tissue relationships than thin
sections. 
In the search for better resolution, I hope that histologists remember
that in studying tissues there is a place for both thin and thick
sections. Barry