Xref: utzoo sci.bio:1086 bionet.software.pc:22
Path: utzoo!mnetor!uunet!ig!iuvax!silver!chiaravi
From: chiaravi@silver.bacs.indiana.edu (Lucius Chiaraviglio)
Newsgroups: sci.bio,bionet.software.pc
Subject: Re: digitizers and software: request for information
Message-ID: <1471@silver.bacs.indiana.edu>
Date: 12 Apr 88 22:54:08 GMT
References: <3830@medusa.cs.purdue.edu>
Reply-To: chiaravi@silver.UUCP (Lucius Chiaraviglio)
Organization: Department of Molecular, Cellular, and Developmental Biology at Indiana University, Bloomington
Lines: 56
Keywords: digitizers,histology
Summary: MUCH SIMPLER METHOD RECOMMENDED -- SAVE MAJOR $$$$

(This messed up the first time I tried to post it, I think -- sorry if anyone
gets it twice.)

In article <3830@medusa.cs.purdue.edu> riedl@cs.purdue.EDU (John T Riedl)
writes:
>My wife is working in a neuro-biology lab that frequently needs to
>measure volumes of parts of brains and spinal cords.  Their current
>approach is to slice the brain into cross-sections, draw on paper an
>outline of the interesting part of each cross-section using a drawing
>microscope, compute the area enclosed by each curve using a mechanical
>digitizer, and approximate the volume by summing the areas of the
>cross-sections.  The lab is considering alternate approaches that
>would speed up this process.
>
>One possibility would be to buy a digitizer pad for their PC. . .

	I have a simpler and cheaper solution to offer.  Simply submerge the
sample whose volume you want to measure in isotonic buffer (to avoid having
it expand or contract due to osmotic effects, and to avoid damaging it).  The
container you do this with should be graduated, or, if the graduations on
containers useable for this are not accurate enough, it should be filled to
just the point of overflowing, with things arranged so that all the overflow
goes into a graduated cylinder.  The rise of fluid level in the first case, or
the amount of overflow into the graduated cylinder in the second case, is the
volume of your tissue sample.

	If samples are very small but damage to the samples is not a problem,
you could use an organic solvent like hexane, which wouldn't give as much
surface tension problems as aqueous solutions (less viscous) -- note however
that highly fluid organic solvents also evaporate rapidly in an atmosphere
that is not saturated with solvent vapor (not an insurmountable problem if the
stuff is decently far down in a narrow graduated cylinder, and if drafts are
kept away -- the solvent vapors are heavier than air, and will build up to
near-saturation in the graduated cylinder in a short time.

>Do any of you have experience with these or other methods for
>approximating volumes during histology?  I would appreciate leads on
>hardware, software, and alternate methods.

	I do not have any experience with this method, but it is simple
enough and cheap enough that they are definitely worth a try.  Besides, it
is tried and true -- some Greek discovered it thousands of years ago.  (-: :-),
but it's true.

>Thank you,
>
>John Riedl
>{ucbvax,decvax,hplabs}!purdue!riedl  -or-  riedl@mordred.cs.purdue.edu

	-- Lucius Chiaraviglio
	   chiaravi@silver.bacs.indiana.edu
	   lucius@tardis.harvard.edu	(in case the first one doesn't work)
-- 
	-- Lucius Chiaraviglio
	   chiaravi@silver.bacs.indiana.edu
	   lucius@tardis.harvard.edu	(in case the first one doesn't work)