Dear Kathy,

        We inject fluorescent 10K dextrans into zebrafish spinal cord
and invariably get labeling of the blood vessels which is very
bright and very persistent!  In the transparent larvae, it is easy
for us to see blood flowing through capillaries throughout the CNS.
(What we actually see is "dark" blood cells flowing against a
light background, that light background being the blood).

I think Molecular Probes makes an Alexa-dextran in this
wavelength range, but you should check with them.

Good Luck,
Don


On Wed, 14 Nov 2001, Kathy Spencer wrote:

> Hello All!
>         I am in search of a dye that is excited at 647nm and fluoresces
(sp?) at
> 680-ish. We want this dye to be injectable and circulate in the blood
> vessels, giving us a vascular road-map (the 520 and 598nm emission markers
> are already taken). Without totally redesigning our experiment, can anyone
> suggest an appropriate dye/stain? We tried injecting Alexa Fluor
> 660-labelled irrelevant antibody, and it didn't work. Someone suggested
> FACS bead standards...any other suggestions?
>         Kathy Spencer