IB> In article <3i9s7o$dtl at dux.dundee.ac.uk>, (k.c.breen at dundee.ac.uk)
IB> writes:
IB> > One method to differentiate neuroblastoma cells is to treat the cells
IB> with
IB> > retinoic acid (RA). I have seen two protocols; one uses RA in ethanol,
IB> the
IB> > other RA in DMSO. Both are made up at a stock of 10-2M and then
IB> diluted 1
IB> > in 1000 when treating the cells. Which method is preferable, or is
IB> there
IB> > any particular difference? Furthermore, I believe that RA is
IB> > light-sensitive and the solution is unstable. Would anybody have
IB> > suggestions for storage conditions, and is is sensitive to repeated
IB> > freeze-thaw cycles?
IB> I have used retinoic acid to differential N-tera 2 cells in culture. I
IB> usually
IB> dissolve an ampule at a time in DMSO. I have no experience with EtOH.
IB> I am
IB> told that drugs dissolved in DMSO can be absorbed through the skin, so
IB> wear
IB> gloves when handling this RA solution. I similarly use a working
IB> solution of
IB> 10mM and dilute it to 10uM in my growth media. Retinoic acid is light
IB> sensitive, so I store it covered at -80 degrees. I aliquot my samples
IB> into
IB> individual tubes and have not trusted RA that has been thawed and re-
IB> frozen.
IB> I
IB> have also found that the effeectiveness of RA in differentiating NT2
IB> cells
IB> diminishes after about a month of storage, so only make up enough for a
IB> month
IB> of experiments at a time.
IB> I hope this is helpful.
IB> Brian Brooks
IB> University of Pennsylvania School of Medicine
IB> Philadelphia, PA
To add to the DMSO caution: Yes, penetrates the skin faster than any
known solvent next to acid which of course eats away anything it penetrates.
Yes, solvent. I currently use DMSO for pain relief and reduction of
swelling; both topically and intramuscular. Reports suggest that it might
replace needle injections albeit FDA disapproval.
bruce
a tai chi player
* Q-Blue v0.7 [NR] *
--
DSP Information & Entertainment, Personal & Professional Internet services,
email info at dsp.com with send index as topic for information about DSP I&E
services. Or use (510)865-9778 for direct access and free trial.
