[Histonet] in-vivo imaging techniques

[Maria Mejia]

Hello Everyone,

I posted this message last week (and) I have yet to receive any 
responses. So, I've decided to
send the message...again. In hopes of something. This time my message is 
a bit more
detailed. Keep in mind that the company who make the dye (they have the 
patent), isn't more
helpful.

Please, can anyone help, especially the neuroscience folks?

One of the PI's I work with is interested in in-vivo imaging techniques. 
We've been trying
for sometime (w/out consist success) to use a particular blue voltage 
sensitive dye called
RH-1692. This type of imaging is a hot new area!! The dye compound is 
used for low
biological noise probing for high-speed in-vivo neural imaging of 
electrical signals.

The problem is in the dye preparation. You wouldn't think this would be 
a problem, but it
is!! I have to weigh very tiny amounts at a time (1mg), the compound is 
very sticky (and) it's
also hygroscopic - sucks up water from the air, thus gets more sticky!!

Compound is also light sensitive, so I wrap the vial(s) in foil and work 
in very dim room.
When not is use the dye is stored @ 4 degrees and when used is mixed 
with either home
made or commercial artificial cerebrospinal fluid (CSF) and heated to 
about 50 F degrees
to dissolve. Did I mention that its not easy to dissolve; we've used 
heating the mixed solution,
sonicating it to help it dissolve faster and also have tried using less 
heat...nothing!

The good (but frustrating) news is that it did work twice (2) 
experiments of of six (6). Which
leads us to the possibility that the stock dye might be suspect. We've 
also used dye with
different lot numbers, same results...inconsistancy. So, unless we get 
some specific details
on this dye , hopefully from neuro folks who are generous in sharing 
information technique
and who I can contact directly, we are faced with the possibility, but 
an expensive fact that
we might have to order a new dye vial for each experiment!

Sorry for being lengthy. Any information, suggestions, tips...anything 
anyone can provide, I
would greatly appreciate it and look forward to hearing from you.

most sincerely,

Maria Mejia
neurohistologist
Smith-Kettlewell Eye Research Insititute
San Francisco, CA
Email: maria <@t> ski.org
Phone: (415)-345-2185/2165