Measuring Ear Thickness in CDTH

M. Doherty M_Doherty at NIH.gov
Tue Jul 16 10:47:11 EST 1996


In article
<Pine.SGI.3.94.1.960715133423.16637A-100000 at firebird2.Stanford.EDU>,
Gregory Gordon Johnson <absolute at leland.Stanford.EDU> wrote:

> I am currently performing a cutaneous delayed type hypersensitivity test
> on balb/c mice.  This test requires the measurement of mouse ear thickness
> on a mouse sensitized and elicited with the oxazalone hapten and on a
> control.  The inflammation produced on a  mouse treated with oxazalone is
> not striking, therefore measuring the difference in inflammation
> between the two groups has become a problem.  I am currently using
> calipers that are sensitive to 0.00 mm and measure at the same point on
> each ear.  The problem is when I measure the same ear twice I get
> measurements of .5mm for the first measurement and .32mm for the second
> measurement. I am afraid that when I measure an inflamed ear I could be
> either-- putting too much pressure and squeezing the ear thus giving a
> smaller measurement or not putting enough pressure on the ear and
> receiving larger measurements.  I have tried to measure the ears putting a
> maximum amount of pressure with the calipers but this does not give very
> good results since inflamed ears measure the same thickness as normal
> ears.  If any of you have any good ideas please write me e-mail at
> absolute at leland.stanford.edu or post on this newsgroup. 


Two suggestions.

First, see if you can get your hands on a dial caliper (Mitutoyo makes
some nice models, which you used to be able to buy through US scientfic). 
These are spring loaded, so apply the same pressure at each measurement -
something that is crucial when trying to measure DTH in a mouse.

Second, is it necessary to do the experiments in BALB/c? Mice generaly
give poor DTH reactions compared to some other lab animals and BALB/c (in
my hands anyway) respond less well than other common lab strains (C3H/heJ,
C57BL/6).

Cheers, Mark



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