From: Dace (edace@earthlink.net)
Date: Wed 30 Nov 2005 - 20:46:07 GMT
Derek,
> From: Derek Gatherer <d.gatherer@vir.gla.ac.uk>
>
> Before you start fulminating, Ted, I suggest you re-read Hill's
> paper. (bottom of p212 and the first paragraph of 213). Then reread
> his reply.
I don't see the contradiction. In response to your question, Dr. Hill said
that at each passage the culture was divided into two subpopulations which
were both placed in clean flasks. Here's what he wrote in his paper:
"Briefly, cells in the logarithmic phase of growth are, at each passage,
divided into two unequal samples and subcultured by seeding the large sample
into a selection medium and by growing the small one in a parallel culture
without selection."
No contradiction there. Perhaps you were thinking of what he wrote next:
"The cell monolayer in the selection medium, when depleted, is periodically
replenished by the addition of fresh cells from the parallel culture."
This is a separate issue, having nothing to do with splitting the culture at
each passage. Since the exposed culture is depleted by the toxin, it has to
be replenished with cells from the unexposed culture. Are you suggesting
that this somehow contaminated the unexposed culture? You have yet to
explain how Dr. Hill's results were compromised.
ted
> At 21:26 27/11/2005, you wrote:
> > > From: Derek Gatherer <d.gatherer@vir.gla.ac.uk>
> > >
> > > Just ask him. I think you'll find the reply interesting.
> >
> >As I expected, Dr. Hill says the cultures went into clean flasks. I
> >refrained from passing on your question because, frankly, it's insulting.
> >Of course he used clean flasks! The man is a highly respected scientist.
> >He's obviously not going to put his cultures into used flasks.
Fortunately
> >I didn't have to send him your question as he found it himself on the web
> >and graciously passed on his answer to me. Here's his post:
> >
> >Dear Ted Dace,
> >
> >Incidentally, I have stumbled on the question by Dr. Gatherer who wrote:
> >"What I'd like to ask Dr Hill is, when he splits the unexposed culture,
do
> >the cells to be exposed to the agent go into the same flask as the
previous
> >exposure was carried out in? Or is the exposure culture set up in a clean
> >flask each time?".
> >
> >The answer is as follows: At each passage, the cells are split into two
> >subpopulations. One of them (a small one) goes into a clean flask with
> >growth (nontoxic) medium and the other one (the large one) into a clean
> >flask with toxic medium.
> >
> >Dr. Gatherer can send next questions directly to me on my address
> >hill@infobiogen.fr. I am not used to forum discussions on the Internet
> >though I read my email.
> >
> >Sincerely yours,
> >Dr. Miroslav Hill
> >
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