Stizolobic and stizolobinic acid-action in mammals?

[Limpet_Chicken]

God damn I am driving YOU barmy?

That is my point, and probably Hammy's too, it is relative! think of it this way:

One weighs, using a scale accurate to 1mg with a -/+ 0.5mg drift, a milligram of say, for example's sake, 1mg of DOB.

That is an error margin of 0.5 (I think, please feel free to correct my very, very shitty math if needs must, just tell me WHY I am wrong, should I be, and I probably am), not much, although significant with DOB, one can then dilute to 0.5mg with the same error margin, which would become MORE significant, if one were to dilute that 0.25, or more, using a burette calibrated very prescisely.

Increasing relative error margin (relatively speaking) exponentially with further dilution, although slightly, it becomes more and more significant the more dilute one gets, as the prescision of the instrument used varies more and more, relatively, the more prescise one has to be.

With something in the attomolar range, Jebus C.H.Rist! that is so fecking potent that the smallest variation in say, the internal diametert of a capillary tube used to draw up a solution is enough to twattify the experimental result.

With an 0.5mg drift, would someone calculate the requisite math for me? I really cannot do it, but to calculate a few attograms to even the remotest degree of accuracy, using a dilution series, the original measurement has sufficient margin of error to render any calculation of concentration based upon that measurement totally, utterly innaccurate.

 

[MurphyClox]

First, weighing out 1 mg of anything with scale that got an error of +/- 0.5 mg is pointless. That's 50% error!!! No way. You could get 1.5 mg as well as 0.5 mg...

Second, I will admit that I maybe confused the terms absolute and relative. If you have for example a concentration of already 1 nM and take from this solution 1 ml with a burette that got an accuracy of +/- 0.001 ml, the error is still negligible.

OK, let me ask this time: How do you think then are nM or pM concentrations prepared?! How are homeopathic preparations done, often applying dilutions beyond 10^12? HOW I ASK YOU?

Murphy

 

[Limpet_Chicken]

I know its pointless using such a scale for that kinda measurement, I was only using it as a theoretical example.

AFAIK high dilutions of compounds are done using methods applicable to the particular class of compound, e.g peptides and proteins are often done by immunofluorescence, and others are done by radioimmunoassay, and antibody-involving techniques, I don't pretend to be an expert in the field, at all, not that it excuses me from lacking knowledge, but I was only educated to GCSE level (UK exams taken at 16 in high school, and the limit of O-chem they teach is alkanes, alkenes and alkynes )

As for homeopathy, again, I am not a homeopath (nor would I be, its an unscientific load of betty swollocks ) they take a smal quantity of a stock tincture of a 'remedy' (and yes I think its an insult to the term remedy, to use it referring to homeopathy) then dilute it again with a volume of water, which is shaken, then again a tiny amount of the secondary dilution is shaken with more water, etc. etc. etc. until theres bugger all left in there.

They aren't scientific in their approach to medical practise, so there is no reason to believe they are in their approach to weighing at all, hehe, its not like it works anyway, so why bother weighing out THAT accurately, they aren't interested in measurement to a billionth of a percent with formal accuracy that would be accepted in a journal article

Please, don't cite homeopathy as scientific evidence, they wouldn't know the bloody meaning of the term evidence.

Its a matter of scale I think, not the instrument, but scale as in magnitude, with something potent in the milligram or microgram range an error of a picogram or nanogram would be acceptable, but measuring something to attogram accuracy, one picogram is already an error of 1000%

I don't KNOW how it is done in practise, in scientific research, but I do want to know, I'm just that type of person.

 

[MurphyClox]

1. Antibodies (i.e. immunofluorescence, radioimmunoassay and alike) are used to measure activity or sheer presence of a given molecule. They do not substitute a scale. Preparing a defined solution and measuring what's inside are 2 completely different issues.

2. I agree that the medical background of homeopathy is some kinda mumbo-jumbo. But the technical background is quite solid. Homeopathic preparations are anything but sloppy made! If they actually work is a totally different issue again, which I don't wanna discuss. I think we share the same sight of things here...

3.

they take a smal quantity of a stock tincture of a 'remedy'... then dilute it again with a volume of water, which is shaken, then again a tiny amount of the secondary dilution is shaken with more water, etc. etc. etc.

Exactly. And they do this indeed very carefully and accurate. Sounds awefully similar like the procedure I described already several times before. How come, you ponder? Because it's exactly the same, a 'dilution series'.

4. No, I won't cite homeopathy as scientific evidence per se (...'cause it's NOT really scientific, here you got a point), but as said before, their techniques are reliable! Don't confuse this.

5.

Its a matter of scale I think, not the instrument, but scale as in magnitude, with something potent in the milligram or microgram range an error of a picogram or nanogram would be acceptable, but measuring something to attogram accuracy, one picogram is already an error of 1000%

I'm convinced, you're not getting my point! I don't talk about weighing out anything in pg or ng! That would be senseless!

The idea behind serial dilutions is that you weigh out an amount which you can handle with negligible error, dissolve this in a relatively huge volume (like 10 mg in a 1000 ml; such a volume can be measured with great accuracy, too!). Then you take again a volume which allows accurate handling (like 1 ml; that's still OK for modern equipment) and dilute this again by filling up to, lets say 1000 ml. Repeat this and you always deal with an error margin of less than 0.01% in each step!!!
So, while you're always on the 'accurate side of life', you will indeed reach attomolar concentrations with sufficient precision!

I can't tell you more, I'm already repeating myself several times. It's not that I'm fed up of discussing (never! ) but feel a lack of appropriate vocabulary to make my point clear.
I'm still absolutely convinced that I'm correct. We should ask like FnB or Vecktor, both are native english speakers and can express themselves far better than me... Sorry to say so...

Peace! Murphy

 

[Limpet_Chicken]

Hm, hehe, I think we are not getting each other's points.

What I mean, to put it quickly, is that the original measurement of a known quantity will probably be done with a scale, if you take 1mg and wish to weigh a few ag, the original scale used, won't be able to weigh that 1mg out with attogram prescision, so the margin of error is already there from the first step, as the mg/mcg scale will weigh out that 1mg, but it won't weigh it out to within a llight year of ag prescision.

From the weighed quantity being innaccurate to the degree of prescision expected from the liquid dilution measurement, especially when its not just one, but several orders of magnitude smaller than the resolution of the scale used for weighing out the 1mg, surely that imprecision would grossly impair the accuracy of the liquid dilution.

Garbage in, garbage out, as they say in the computer field.

 

[MurphyClox]

the original measurement of a known quantity will probably be done with a scale, if you take 1mg and wish to weigh a few ag, the original scale used, won't be able to weigh that 1mg out with attogram prescision, so the margin of error is already there from the first step, as the mg/mcg scale will weigh out that 1mg, but it won't weigh it out to within a light year of ag prescision.

The trick is: It doesn't have to!!! That's why you start with an amount that can be handled accurately! The error is of each step is so infinitesimal that it doesn't matter.

Your logic is faulty, pal! IF the scale was supposed to be accurate in the attogram-range, THEN why don't you weigh out directly your needed amount? The answer is obvious: It can't be done with enough precision. (here we both agree, fortunately) Therefore you try to stay always in ranges that allow you handling with minimal error.

Murphy

P.S. Sorry, we have to continue tomorrow, I'm leaving for a party. I will convince you and your heretic fellow Hammilton!

 

[Limpet_Chicken]

If one starts with an accurately weighed quantity, to 1mg, its accurately weighed TO 1mg, the dilutions will be innaccurate at ag quantities BECAUSE the original weighing is only accurate to mg/mcg in the first place.

Have a good party

Just don't try measuring out any uber-potent drugs or poisons while yer wasted

 

[SweetSpot]

Arrgh MurphyClox I feel your pain! your english is fine and you're describing it text book - I don't understand why people aren't grasping it - the homeopathy example you gave sums it up, and they are accurate.

 

[kidamnesiac]

Seriously Chicken, you need to go back go your gen chem lab and realize that dilution series is used everyday exactly as murphy is describing it and he is exactly correct. you weigh a gram of material, dilute it 10^x fold and your measurement is accurate as your scale is @ 1g, which is usually quite accurate for real chemists.

 

[Hammilton]

However, if your scale at 1g has a 100ug error, that's 10^14 attograms. If you're off that much at the beginning, you're going to be off a smaller portion, but still a truly massive number in attograms.

You have to dilute it in half 40+ times before your error is into the single digits of attograms.

which is usually quite accurate for real chemists.

If these 'real' chemists are working with things where a margin of error of 100ug is fine, then yes.

However, we do have 'scales' that can measure accurately in this range.

 

[kaskelot]

An error of 0.1% at 1 gram will still be an error of 0.1% after dilution, the error does not accumulate with each dilution. The 100 microgram error gets sort of diluted as well, and is constant as a percentage.

Dilute 1 gram +- 100 microgram of example material in 100 centiliters of example solvent, measure out one centiliter. It then contains 10 milligram +- 1 microgram of example material in solution, not 10 milligram +- 100 microgram.

The technicalities involved in error compensation when using pipettes, volumetric flasks, and whatnot, I know nothing about. But it's pretty simple math Murphy is trying to explain.

 

[MurphyClox]

Have a good party

Just don't try measuring out any uber-potent drugs or poisons while yer wasted

Damn! I was already logged out when you typed these precious lines....Now it's too late. :D
______________________________

An error of 0.1% at 1 gram will still be an error of 0.1% after dilution, the error does not accumulate with each dilution. The 100 microgram error gets sort of diluted as well, and is constant as a percentage. [1]
...
The technicalities involved in error compensation when using pipettes, volumetric flasks, and whatnot, I know nothing about. But it's pretty simple math Murphy is trying to explain. [2]

[1] Exactly! My words, so to say Finally somebody explains it in proper words...

[2] Yep!
______________________________

Now somebody please convince my pal Hammilton as well!

Peeeeeeeeeace! Murph

 

[Limpet_Chicken]

Kaskelot, thanks for simplifying that one a bit, I shoulda thought of that, I just...didn't.

Although what may be simple math for you, isn't nescessarily simple for everyone, especially those who are dyscalculic
Completely flunked GCSE math back in my school days.

BTW kidamnesiac, what does 'gen chem' stand for? assuming its a US based exam?

Anyways, back to the actual original subject of the posts perhaps? :D

 

[mutnat]

Hello, well, I will now try to bring the topic back to its origins, since a friend brought this topic to my attention, and I have used amanita pantherina a couple of times last season

I admit, I am chemistry/biology illiterate, or rather just generally informed, so I would love if someone explained to me, even with 1/10th of the patience you explained to Limpet_Chicken the dilution thing , the following:

Where do we see in these abstracts or how do we reach to the conclusion that there might be some disturbance in memory [I understand it's only hypothesis, or is it more than that?] ? What is excitotoxicity?

How is stizos linked related with acros, chemical resemblance? Because I get the impression that you begin to talk about acros from a point and on, which seems rather irrelevant to me, since, not even close to enough were told about stizos themselves...

Please explain in a more everyday language why there might be more risks in using pantherina , compared to muscaria, as an accasional inebriant or dissociative, and why is that....

Thanks in advance

PS: What is BBB?

 

[Xaratoostrah]

Well, Mutnat, let me elucidate some "technical terms" for the time being so the other answers that will follow would be more straight to the core of your interest (the "stizo" compounds)

What is excitotoxicity?

Excitotoxicity is a kind of neurotoxicity, that is neural cell death. It literally means that too much excitation for a cell can prove toxic for it. As a phenomenon it is exhibited in the glutamate neurotransmission. Certain substances ,along with glutamate, can literally excite neural cells that carry receptors for them to death.

What is BBB?

Oh ,we aint telling! Its too sexy to be told!

On a more serious note, BBB stand for "Blood Brain Barrier".Its the mechanism that selectively allows for certain substances to enter from the bloodstream into the brain. Now, everything that flows in your blood ,doesnt make it inside your neural tissue, some molecules for example cant cross, bacteria also dont cross easily. Its both a gift (protecting the sensitive brain tissue) and a curse -if one wants to administer a medicine to the brain that CANNOT cross the BBB).

 

[Hammilton]

well, there are definitely ways to get something that can't cross into the brain. Best is to inject it straight into the brain.

Some things are able to get in, but are actively removed.