Why use invasive methods to evaluate cellular viability if non-invasive methods exist

[soundlover]

Hello All

I have this issue to discuss in my cellular physiology class:

"It is useful to evaluate cellular viability thru invasive methods? "




First of all, the concept of "cellular viability" can be understood as the capacity of the cell to multiply, right?

what is a invasive method? what does that mean? an invasive method must, by definition, make some (irreversible ) damage to the cell? (damage on the plasmatic membrane for example). what invasive methods to evaluate cellular viability do you know?

and NON-INVASIVE METHOD´S? can you name a few of them? what are the real advantages of this method, in relation with the INVASIVE METHOD´S?

is there any invasive method that can evaluates some particular characteristic of the cellular viability that no other NON INVASIVE method would be able to do?


tks in advance for any answer
take care

 

[pattylou]

Is the general idea that we are talking about cells in culture (rather than in living organisms)?

Invasive in *that* sense, might be any process that interferes with the central workings of the cell: DNA funcion, RNA function, Protein function. For example, if you wanted to ask if a plate of cells were dividing, you might add some DNA-specific dye. But, the dye will almost certainly interfere with the cell division. I think the dye could be called invasive.

Something like phase contrast microscopy (no dyes, very little heat from the light source, sample kept moist etc) would be non-invasive.

In the case of living organisms, invasive has other meanings. Surgery is often invasive. I take it this is not what we're talking about?

 

[Moonbear]

An electrophysiological recording that requires a very fine pipet with recording electrode be "poked" through the membrane, or to otherwise increase the porosity of the membrane, could be considered invasive. It is used as a measure of cellular activity/response, so I don't know if that would fit your criterion for viability in the context of your assignment.

 

[Lopes Alves]

Is the general idea that we are talking about cells in culture (rather than in living organisms)?

Invasive in *that* sense, might be any process that interferes with the central workings of the cell: DNA funcion, RNA function, Protein function. For example, if you wanted to ask if a plate of cells were dividing, you might add some DNA-specific dye. But, the dye will almost certainly interfere with the cell division. I think the dye could be called invasive.

Something like phase contrast microscopy (no dyes, very little heat from the light source, sample kept moist etc) would be non-invasive.

In the case of living organisms, invasive has other meanings. Surgery is often invasive. I take it this is not what we're talking about?

Hi

I'm a colegue that is working with soundlover in the same question...

We are talking about cells in culture...

If we could just find one Invasive Method that can evaluates some particular characteristic of the cellular viability that no other NON INVASIVE method would be able to do, we might find the answer to the question...we might find a reason that turns invasive method a useful thing...

The problem is how to define CELLULAR VIABILITY...which parameters define cellular viability??Integrity of the cell membrane??Metabolic rate??Cellular division??

Another problem is how to define Invasive Method's

 

[pattylou]

I'd personally go with metabolism, to define viability, but your prof may have a different idea about it. Cell division is not a bad criterion, the problem (of course) is that a cell can be perfectly viable and just not have the right signals to replicate.

Obviously the cell membrane has to be intact. But that alone isn't sufficient to say that the cell is viable, at least in my opinion. Your prof may have a different view. I haven't studied cell membranes extensively.

Either metabolic rate or division would seem to be the way to go and in *either* case you may be able to come up with some assay that would both (1) seem to allow for assessment of cell number/viability and yet (2) disrupt the cells such that they are no longer viable.

It sounds like you're thinking about it - I'd suggest that if you *don't* have time to get your specific concerns about the question addressed by the instructor or a TA, that you state your working assumptions in your answer. Of course, asking for clarification from the instructor or TA first would be best. But maybe this is due tomorrow. :)