DNA damage via radiation conversion.

[Ishy]

I've got a bit of a painful question. I'm looking at several different articles that mention radiation damage to DNA quantitatively, but they use vastly different ways of representing this damage.

So my question is, is it possible, first of all, to convert between umol/J (micromoles per joule) and SSB/bp/Gy (single stranded breaks per base pair (actually nucleotide) per Gray)? One would of course have to assume the type of radiation (gamma, in this case). Secondly, I'd be interested in some direction as to how this could be done.

 

[Ishy]

Okay, I really hope I'm not breaking the rules by replying to my own post (I read the rules, I didn't see it there, but I know some boards have that rule ... /sweat). I have something of an update to my original query, and I was hoping that the blanks could be filled in.

And I'm sorry that this is so ugly:

In the first case, we have a yeild of Single Stranded breaks in micromoles per Joule:

umol/J

To rephrase this in terms of SSBs, apply Avogadro Constant tremembering umol, not mol:

6.022x10^17 SSB/J

And that's as far as I get on this side of the problem. But there's another side of the problem (oh joy):

SSB/bp/Gy

Now, this phrasing is just unpleasant as we are dealing with single stranded breaks in a single stranded scenario. So if there's 1 SSB/bp, there's 1 SSB/2nuc (nucleotides).

SSB/2nuc/Gy

And 1 Gy = 1 J/kg. So it follows that:

SSB/2nuc/J/kg

or:

SSB/2nuc * kg/J

and since we want this to approach what we've got up top, I'm going to collect the SSB and J to rewrite:

SSB/J * kg/2nuc

soooooo, we're left trying to equate, or find a conversion factor for:

6.022x10^17

and

kg/2nuc

Is this possible?

 

[quicknote]

I can understand your confusion with the different ways of representing DNA damage caused by radiation. The conversion between umol/J and SSB/bp/Gy is possible, but it is not a straightforward process. It requires several assumptions and considerations, such as the type of radiation and the energy of the radiation.

To convert between umol/J and SSB/bp/Gy, we first need to understand the units involved. Umol/J represents the number of micromoles of a substance per joule of energy, while SSB/bp/Gy represents the number of single stranded breaks per base pair per Gray of radiation.

To convert between these units, we need to consider the energy of the radiation. For example, if we assume that the radiation is gamma radiation, we can use the conversion factor of 1 Gy = 1 J/kg to convert from umol/J to SSB/bp/Gy. This conversion factor takes into account the energy absorbed by a kilogram of tissue, which is a crucial factor in determining the extent of DNA damage.

However, it is important to note that this conversion is not a direct conversion and it only provides a rough estimate of the DNA damage. This is because the amount of energy absorbed by different types of tissues can vary, and this can affect the extent of DNA damage. Additionally, the type of radiation and its energy can also impact the conversion.

In terms of direction, I would recommend consulting with experts in the field of radiation biology or radiobiology to get a more accurate understanding of the conversion and its limitations. They can provide you with more specific information and guide you in the right direction. Additionally, conducting further research and comparing data from different studies can also help in understanding the conversion between these units.

In conclusion, while it is possible to convert between umol/J and SSB/bp/Gy, it is a complex process that requires careful consideration of various factors. I hope this response has provided you with some direction and clarification on the conversion between these units.