RE to Jim 3975 - Strong contamination with ethidium bromide

Dear Jim 3975,

of course, and as anybody in this field knows, you're right: my story
was simply to tranquillize this poor undergraduate student...I think
that your intervention got the opposite result! Another very relevant
aspect of this specific case (mine and undergraduate's one) is that we
are speaking of a SINGLE exposure, far less effective in terms of
carcinogenicity as compared to CHRONIC exposure.
By the way, if there's anybody who stained his hands with EB more than
16 years ago, please come on and tell us your story!



Prof. Piero Sestili
Istituto di Farmacologia e Farmacognosia e
Centro di Ricerca sull'Attività Motoria
Università degli Studi di Urbino "Carlo Bo"
Via "I Maggetti" 26
61029 URBINO (PU)
Tel. 0722 303414; 0722 305524
Fax 0722 303401


-----Messaggio originale-----
Da: [Only registered users see links. ]
[mailto:[Only registered users see links. ].indiana.edu] Per conto di Jim 3975
Inviato: giovedì 7 giugno 2007 22.00
A: [Only registered users see links. ]
Oggetto: Re: Strong contamination with ethidium bromide


To get cancer, 16 years is nothing. People who start smoking at 16 don't
get
lung cancer until 40, 50 years later. (Average age of lung cancer death
is
~70)
Bruce Ames showed in a PNAS paper in the seventies that smoking is more
mutagenic than ethidum bromide (using fairly realistic doses of both).

stain



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On Jun 8, 6:15 am, "Prof. Piero Sestili" <[Only registered users see links. ]> wrote:

EtBr is overrated IMHO, Friend of mine spilled about 250ml on himself,
did not change clothes for a few hours and 14 years later he is fine,
has 3 children and all is as normal as it can be. Don't stress
yourselves with EtBr/gloves etc. In my experience most contaminations
happened when people wore gloves....just wear gloves when handle
acrilamide , DMSO, PMSF etc.

In article <1181318252.993588.241960@p47g2000hsd.googlegroups .com>,
peter <[Only registered users see links. ]> wrote:


I used to have a supervisor who handled agarose gels containing EtBr
with his bare hands. More than 16 years ago. He used to say that indeed
the danger of EtBr is way overrrated: as with propidium iodide (which is
used to stain leaky DEAD cells), you actually need to actively open up
the cell membrane to get it into the cell. I have no other reference
with regard to EtBr to back this up, but his reasoning made a lot of
sense to me.
I use gloves, just because my institute requires it when handling this
type of chemicals.

Bas

In article <1181318252.993588.241960@p47g2000hsd.googlegroups .com>, peter <[Only registered users see links. ]> wrote:


Lotsa examples like that. It certainly never occured to me to wear
gloves when I was handling a lot of ethidium and propidium
bromides some 20 years ago. No spills that I know off, though.


Exactly!


What's wrong with DMSO? Sure, it goes through the skin easily
and all that but on its own it is pretty harmless. The danger is
there only when handling toxins dissolved in DMSO, I think.

Half the same goes to acrylamide. When a gel is poured
and handled properly, there is zero chance to ever come in
contact with it. If, however, you accidentally spilled few ul or ml
on a skin - just wash it off right away and no harm will ever
be done. Paying attention is 1000X safer than wearing gloves
(which should only be worn when contact is either inevitable
or deadly).

On Jun 8, 9:37 pm, [Only registered users see links. ] (DK) wrote:

DK probably DMSO won't harm you much, but it is known terratogen....so
for the sake of the future generations and because goes well trough
the gloves, be careful. I agree 100 % with your last statement, don't
get me wrong.

In article <1181355587.090294.318880@k79g2000hse.googlegroups .com>, peter <[Only registered users see links. ]> wrote:

I am not arguing for the sake of argument... I just could never
understand those warnings about DMSO. Teratogen, sure. Half the things
are teratogens. Then again, as I am sure you know, cells (including
stem cells), oocytes and whole embryos are routinely cryopreserved
with very high (10-20%) DMSO concentrations. So it can't be all that
bad by itself.

DK

Prof. Piero Sestili wrote:
Well, this is second hand information, but I know a woman who worked in
the Sambrook lab at the time when the protocols for Molecular Cloning
were being optimized. As you might expect there was a lot of ethidium
bromide in use, and she never used gloves while testing these protocols.
More than 20 years later and not a sign of finger cancer.

Hi Piero,
Well I have been working with EBr in a rather sloppy way (some of my
colleagues would use stronger terms) since like thirty years. 'Finger
cancer' (as someone else in this thread called it) is not among the
problems I currently have, nor of any of my lab colleagues. (I must say I
took care never to ingest any, I mean washing my hands before eating etc. )

My reference to the PNAS paper was as sloppy as my way of working with EBr.
The paper mentions Ebr, but not cigarette smoke. That must have been a
different paper, I can't find it right now.
Even if carcinogenity would be similar, it would be odd - just as you are
correctly pointing out - to panick about having smoked say, 50 cigarettes
_only one time_.

BTW, it is funny that there do not seem to be reports of studies of the
effect of EtBr on animals. After all, strong mutagens can be helpful in
cancer studies.
cheers,
Jim


"Prof. Piero Sestili" <[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]. net...

Historians believe that in newspost <Gvnai.32$%[Only registered users see links. ]> on
Sat, 9 Jun 2007, DK <[Only registered users see links. ]> penned the following
literary masterpiece:

The problem with users and gloves is that they get very blase about
having protected themselves from the spillage they have just had. They
then go and touch draw handles, door handles etc. with contaminated
gloves, without thinking, so the rest of us get caught out.

I wear gloves for acrylamide and making up stocks of EtBr or real
nasties. After 30 years in a lab, despite handling EtBr gels without
gloves, I am still live and licking with two 'normal' daughters one of
whom got her finals result yesterday with a 2.1.

Duncan
--
I love deadlines. I especially like the whooshing noise they make as
they go flying by.

Duncan Clark
GeneSys Ltd.

On Mon, 11 Jun 2007 12:42:33 -0400, "Jayakumar, R"
<[Only registered users see links. ]> wrote:


Acrylamide monomer is known to be a neurotoxin, so it is worth taking
good care when handling unpolymerised acrylamide. Nothing to do with
safety in lab, but there was this sensational case of the deliberate
"poisoning" with acrylamide -

[Only registered users see links. ]

The accused got away scot free. Nothing was proved of course. I do
wonder however why we don't actually see more of this kinds of cases,
since we have access to all kinds of poisons in the lab, and we all
know of the liaisons, passions, conflicts, arguments and hurt that go
on in labs.