(kein Betreff)

I read somewhere that EtBr can cross through latex gloves (nytrile gloves are safe)---just to add to the hysteria. :P


On 11/11/09 4:08 PM, "Allan" <[Only registered users see links. ]> wrote:

Hi!

I'm back to the old ethidium topic again! I have been working with this
chemical a lot over the past two years and have been wondering how
mutagenic/carcinogenic/teratogenic it actually is in the body. I can't
imagine whether it will be resorbed via the skin into the blood system
or whether a polar molecule of this size will cross the blood-brain
barrier/seratoli barrier/placenta.

Don't get me wrong, I am careful with this substance, but being quite a
worryful person, I am sometimes worried that somewhere in the lab there
could be contamination from coworkers (you can't always run around with
a UV light)

Different people in the lab treat the chemical with different degrees of
caution and I just wonder whether microgram quantities present a serious
risk or if they are rather more comparable to smoking a cigarette.

I sometimes ask myself whether the amount of hysteria made around etbr
is justified when chemicals like formaldehyde, phenol and chloroform are
also used in the lab.

Does anyone have a clue as to the risk of this chemical (in comparision
to say a cigarette), especially in terms of crossing the placenta etc.
and do you know how long it is stable in normal light?

Thanks for any answers, as I am getting a little worried about the
substance!

All the best,

Allan

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Am 13.10.2009, 10:59 Uhr, schrieb Taliaferro, Dwayne (NIH/NIMH) [F]
<[Only registered users see links. ].gov>:


Now, that would require knowledge about the dangers of those chemicals.
Phenol was used for decades as disinfectant for surgery, a fine mist of
the aqueous solution was sprayed onto patients, physicians and nurses
alike. To the best of my knowledge at least this long-term exposure of
medical personal did not lead to an increase in cancer or in flk (funny
looking kids).

Chloroform was also used during surgery, as a volatile anaestetic.
Although its flammability has indeed caused some problems (not quite as
bad as those with ether, though), I am not aware of any epidemiological
studies showing problems in medical personnel.

And formaldehyde has been "shown" to be carcinogenic in rats by exposing
the poor critters to concentrations of the stuff that no human could
possibly tolerate. But the rats were in a cage and couldn't run away. The
resulting cross-linked proteins in their respiratory tract (remember, even
though formaldehyde has only one aldehyde group, it is a bifunctional
cross-linker) led to chronic immune activation, and /that/ is a well-known
cause of cancer. Again, epidemiology amongst pathologists (who used to use
the stuff by the drum) has never shown increased morbidity or mortality.
That does not mean that formaldehyde can not act as an allergen, though.

Work cleanly, avoid exposure as much as reasonably possible, don't break
the law. But be aware that many experimental scientist before you have
lived long and healthy lifes.