Dear Karolina,

It's rather a strange question... I mean "Without propylene oxide".

You fix the muscle as usual - a mix of GA and PFA in buffer of correspondent osmolarity, sample size not more than 1 mm3, proper washing of the primary fixative, post-fixation in 1-2% OsO4... Where do you see here propylene oxide? It may come only after the dehydration in ethanol series, but could be easly omitted or substituted with pure aceton...

Just look in the dedicated EM papers, you'll make no mistake.

Good luck.

 Dear Yaroslav,

You are right, I didn't ask my question properly. I will explain You what's my problem.

I work on human kidney and muscle biopsies. I use Karnovsky fixative in cacodylate buffer for fixing, after washing  I post-fix in OsO4. Then I dehydrate in aceton series and embed in resin. When it comes to kidneys- the fixation is perfect- but muscles often "crumble" and I don't know why.. I thought that the problem is in aceton which dries the tissue too much but I don't prefer using propylene oxide. In EM papers the inforamtion is usually vestigial..

Could You help me with my problem? I'll be grateful.

@Mohamed Mahdy

Thank You!