Re: 10% NBF for TEM fixation?

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From:"R.Wadley" <> (by way of Marvin Hanna)
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	Dear Carla,

	Fix your zebra fish as per your normal protocol.  Don't post fix
from NBF unless you first wash out the buffer, osmium & phosphate buffers
don't mix very well (nor does uranyl acetate tertiary fixation for that

	10% NBF is NOT a good primary fixative for EM because formalin creates
only temporary single bonds, where glutaraldehyde creates permanent double
bonds for better fixation.  However, if your samples are being delivered to
you it is great to get them in formalin, because it is a very rapid
fixative.  Your modified Karnovsky works this way, the formaldehyde goes in
first stops the autolysis & the glut. comes in slowly creating the
permanent double bonds.

	I had a pathologist who always appologised if my renal sample
arrived in
formalin, but the results were always superior to when the renal came up
from surgery on a bit of damp gauze.  I hope you get the same result.


	Rob W.

At 07:29 01/19/2000 -0700, you wrote:
>Happy New Year everyone-
>Recently we received whole #003#zebrafish mistakenly fixed in 10% NBF.  We
>interested in examining muscle with TEM and usually fix tissues in modified
>Karnovsky's then post-fix in 1% osmium tetroxide.  Would it be better to
>fix directly from NBF or should I re-fix (?) in Karnovsky's and carry on as
>usual?  Also, why isn't 10% NBF suggested as a primary fixative for EM?
>Thanks for your help-
>Carla Aiwohi
>Western Fisheries Research Center
>Seattle, WA
R. Wadley, B.App.Sc. M.L.S, Grad.Dip.Sc.MM
Laboratory Manager
Cellular Analysis Facility
School of Microbiology & Immunology
UNSW, New South Wales, Australia, 2052
Ph (BH) 	+61 (2) 9385 3517
Ph (AH)	+61 (2) 9555 1239
Fax 	+61 (2) 9385 1591

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