Craig,  My first suggestion is to clear the tissue and mount it in either
methylsalicitate or a glyderol buffer moutning media with an anitoxidant. I
think this is your main problem. I have no experience at 364 excitation but
would suggest going to a chromophore you can excite at longer wavelength. Even
in cleared tissue 364 will be strongly absorbed. Send your mailing address or
personal email to [log in to unmask] if you want copies of our papers or
procedures.

The previous response by someone else which unfortunately I deleted was right
on.

Jim

Craig Daly wrote:

> Thanks Jim,
>
> The tissue was delivered to me fixed in formalin and was then transfered to
> fresh saline.  Imaging was with a x40 water (NA 1.13).  Ex 364, Em 400nm
>
> Craig.
>
> >Craig,  We routinely image much deeper than 40 microns, but to comment
> >in detail more info is needed with regard to specimen preparation
> >especially clearing of the tissue which is critical and the objective
> >characteristics especially NA.
> >
> >Jim Turner