[Histonet] Stain vs dye and control

[Barry Rittman]

There is always confusion about this.
In textile "coloring" the term dyeing is used and this first carried over
to histology as many of the textile dyes were the ones first used to stain
tissue components. Some of these were specific and some non specific.

In histology my understanding is that the dye is the powder, while the
stain is the solution used for staining the tissues. and in most cases
there is a certain amount of specificity in the reaction. Merely imparting
a non specific color all components of a tissue I would regard as coloring
as there is no specificity in this process.

This raised the interesting question of what would you call the process
whereby osmium tetroxide is used to fix and stain some fats?

To further complicate in the concrete industry the term dye is used to
indicate a general coloring of the concrete while the term stain  is used
to indicate a chemical reaction with the concrete components.
Barry


On Sun, Mar 8, 2015 at 3:02 AM, Gudrun Lang <gu.lang <@t> gmx.at> wrote:

> Hi Jorge,
> Not all histolabs have access to fresh cultures. So they search an easy
> way to get bacterial controls. And things like sausage are more like the
> usual specimens than liquid samples.
>
> The best staining control is an inhouse-specimen, that is processed in the
> same way as any other specimen (preanalytic, fixation, processing, cutting,
> staining). But sometimes this is not possible, so one uses the "next-best".
> A control with known ingredients (like bacteria) can be used to check the
> whole process and must be positive for the tested parameter. A
> patient-sample can only be considered positive or negative, if the
> positive-control proves the functionality of the process
> (staining-protocol).
>
> Dye and stain. You can touch the dye, but not the stain.  And then you
> have got stained fingers. ;-)
>
> Gudrun
>
>
>
> -----Ursprüngliche Nachricht-----
> Von: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:
> histonet-bounces <@t> lists.utsouthwestern.edu] Im Auftrag von Jorge A.
> Santiago-Blay
> Gesendet: Freitag, 06. März 2015 21:49
> An: Histonet <@t> lists.utsouthwestern.edu
> Betreff: [Histonet] Stain vs dye and control
>
> Dear Histonetters:
>
> Last semester I taught a microbiology lab and, as I was reviewing for
> class, noticed some lack of precision in the use of the terms "dye" vs.
> "stain" in biology. Could someone help?
>
> While I am on "stains", I have been following the emails on controls and
> wonder a couple of things.
>
> 1. What would testing for bacteria on beef jerky, hot dogs or burgers
> accomplish that is different (ideally better) that what one accomplishes by
> pulling out from fresh cultures out of a medium (e.g. liquid, such as
> broth, solid, such as slabs, agar)?  Is it the idea to test for bacteria in
> an animal tissue? If so, would a solid medium (like someone mentioned
> recently, such as agar) do?
>
> 2. An advantage of using fresh bacterial cultures of known Gram is that it
> could be used to test whether the reagents are good enough. Last semester I
> had the suspicion that one (or more) of our Gram reagents where not up to
> par.
>
> If you have any feedback, please feel free to email me directly at
> blayjorge <@t> gmail.com . Thank you.
>
> Sincerely,
>
> Jorge
>
> Jorge A. Santiago-Blay, PhD
> blaypublishers.com
> http://blayjorge.wordpress.com/
> http://paleobiology.si.edu/staff/individuals/santiagoblay.cfm
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