Enumerating fluorescently labelled cells in a hemocytometer

Larry D. Boyd larboyd at sprynet.com
Mon Mar 8 15:04:34 EST 1999

Interesting, but I don't think the fluorescent tempera paint (which color, one
wonders) is the critical element.  From what you are describing, I sounds to me
as if you are creating a type of darkfield condenser and if that is so, any
opaque "stop" might work.

If the tempera is expected to fluoresce and provide a weak direct light source
to illuminate the labeled cells you would need to select a fluorescent paint
that would produce near UV light to fluoresce the cells. And the disk would need
to be thin enough to allow enough light to excite it--and if that were the case
the darkfield might be lost.

I assume you are using full reflected uv illumination? Perhaps a weak
transmitted light source with a full reflected uv source might work.

Have you thought of using transmitted UV phase contrast? that should both excite
the cells and show the grid lines.

In any event go to a shopping mall or "head shop" where students are likely to
hang out, flourescent posters and paints are back in as the kids try to recreate
the 1960s!

Rudi Tapper wrote:

> Does anyone know where I can obtain "fluorescent tempera paint" ? The book
> Staining Procedures [Clark, G. (1981) 4th ed. Williams and Wilkins, page 88]
> states that
> "Since grid lines of a hemacytometer are normally not visible, the problem
> is overcome by inserting a thin piece of cardboard coated with fluorescent
> tempera paint under the swing out lens of the substage condenser. By
> manipulating the light source and condenser height, the light transmitted
> upward from the card illuminates the grid lines"
> If anyone has experience of this procedure and / or knows where I can obtain
> the paint, please could they e-mail me at Rudi.Tapper at port.ac.uk in addition
> to replying to the post on the newsgroup.
> Thanking you in advance
> Rudi
> Dr Rudi Tapper [ www.sci.port.ac.uk/ec/rudi.html ]
> Microbiology Research lab [ www.sci.port.ac.uk/~rzt/home.html ]
> University of Portsmouth
> UK

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