ethidium bromide contamination on clothes

In article <1140237357.755607.66830@f14g2000cwb.googlegroups. com>, "el" <[Only registered users see links. ]> wrote:

No need to be that paranoid. EthBr is very soluble and was washed
away in your washer just fine. Besides, the amounts you are talking
about are incredibly negligible to begin with.

And that is not to mention that EthBr is not particularly mutagenic and
it's carcinogenicity is entirely putative. A single smoked sigarette
contains 100X more mutagenes than the amount of EthBr you are
talking about.

DK

In <dt68un$6qn$[Only registered users see links. ].wisc.edu>,
DK <[Only registered users see links. ]> wrote:


Does ethidium bromide even cross the plasma membrane of intact cells?

AC
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Email: echo 14232209320335931527179462016806497532155427589018 6P | dc

DK wrote:

Are you talking about the results from that Ames test?

Scott.

Aawara Chowdhury wrote:

Yeah, it does, although not as readily as many people think. But still,
I wouldn't be encouraging people to splash it around!

In article <t_yjg.8718$[Only registered users see links. ].au>, SJC <snip.this!-[Only registered users see links. ].au> wrote:

Honestly, I don't remember. Many years ago someone gave a ref. to the
paper, I read it, and all I remember is that it wasn't anywhere a potent
mutagene one might have expected it to be. Maybe it was because
it really is too hydrophilic to cross membrane efficiently?

DK

In message <F9Ijg.44$[Only registered users see links. ]>
[Only registered users see links. ] (DK) wrote:

<<SNIP>>


There has been a long-term hysteria about the dangers of ethidium (a.k.a, homidium) bromide, even though all evidence, and common sense, says that it is doesn't present a great health threat.
Now it is only polite and good lab protocol not to expose your fellow lab workers to any chemical without their knowledge, and that includes ethidium bromide.
But although ethidium bromide does consist of a large aromatic ring complex it is positively charged by virtue of its quaternary nitrogen and that makes a significant difference in how it behaves with cells. Charged molecules (even in most cases small ions) do not pass through intact, healthy membranes.
EthBr is only a problem if you are synthesizing DNA and it is present, where it will cause frame-shifts. In vitro it will cause problems. In cells, and humans, it can only be a problem if it somehow gets into the nucleus of a cell that is replicating DNA. And that is extremely unlikely, for numerous obvious reasons.
Ironically, about 20 years ago the common way of destroying used EthBR was with household bleach (hypochlorite) until someone pointed out that method actually creates nasty by-products which really could cause problems.
Now if you made a habit of eating EthBR (it is supposedly very bitter, I haven't tasted it myself) then you probably run the risk of the liver's P450 system enzymatically modifying the EthBR to something quite nasty, as the liver has a tendency to do with aromatic-ringed compounds it doesn't recognize and confuse it.
I have treated used EthBr with sodium borohydride which reduces (and decolorizes) it. I assume that will render it harmless by any standards.

-DFS

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David F. Spencer, Ph.D.
Dept. of Biochemistry and Molecular Biology
Dalhousie University
Halifax, Nova Scotia, Canada
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