I Would Like Some Help in Understanding the LD50 Table

Thaedion

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I'm using this chart "LD50 Table" to get my numbers.

Okay now Leiurus quinquestriatus has a LD50 (mg/kg) of 0.25,0.26,0.33 depending on the reference, So I take this to mean 0.25mg of venom to 1kg of body weight to be a lethal dose. Now I weigh 104 kg so it'll take 26mg of venom to be lethal? (104 * 0.25 = 26) Now one sting delivers approx 0.62mg of venom so it would need to sting me 41-42 times for me to die on the spot? (26 / 0.62 = 41.9) This doesn't seem right. I need some help understanding the LD50 table please.

Thaedion
 

pandinus

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the LD50 number is the dosage of a toxin expressed in mg of venom over kg of body mass that kills 50% of the test subjects it is injected into, usually mice. Be careful when reading LD50 values, as many times they are not expessing the toxicity of the entire venom, but an individual toxin compound isolated from the venom. because as we all know, scorpion venom is a rich cocktail of a variety of different compounds.

John
 

Brian S

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also what may be "safe" for a mouse may not be so for a Homo sapiens
 

cacoseraph

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also, there are different methods of injecting the fluid being tested.

intradermal (ID) is when an injection is made with the needle entering at a very shallow angle and teh fluid is pushed into the skin and fat covering the animal

intramuscular (IM) is when an injection is made with the needle enterign deeper into the body into a muscle mass. in humans typically this is the gluteus maximus... your butt muscle.

intravascular (IV) is when an injection is made with the needle entering a vein (or artery, i expect it mattter which ;) ). in the movies when ppl shoot up heroin (or whatever) and they pull the plunger back and draw a little blood back into the load chamber they are making sure it is going to be an intravascular injection.

you can possibly see how this could make a difference... something shot intravascularily will disperse throughout an organism's body much faster than something that is injected IM which i believe will disperse faster than something injected ID.

this can be good or bad... intense cytotoxic venom concentrated in muscle and fat and skin would probably eat a meaner hole than if it was injected IV... but it might wreak damage on more of your systems

anyhow, i might have forgot a thing or two or mixed something up... but that should help you out a bit
 

Thaedion

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So the LD50 rating of the LQ (for example) is based not on the numbers of the chart, but on the actual result of the venom? What do the number in the chart mean?
 

fusion121

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Firstly Lq's are not enormously dangerous, even the most dangerous scorpions have extremely low mortality figures for humans down around the 1% mark for the old and or young.

As has been mentioned LD50s are not enormously useful for predicting danger in anything but the most general terms. Its done it mice, its highly variable between experiments and methods etc. Technically for a 104kg mouse a 26mg dose would be lethal in 50% of test cases but its not possible to really make the judgement for humans. And yes an Lq would need to sting allot to deliver that much venom (the figures in the table for amount of venom delivered are pretty iffy since its rarely reported in the literature)
 

Thaedion

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Firstly Lq's are not enormously dangerous, even the most dangerous scorpions have extremely low mortality figures for humans down around the 1% mark for the old and or young.

As has been mentioned LD50s are not enormously useful for predicting danger in anything but the most general terms...
Okay, I'm understanding this a little more... even though the scorpion is listed 'hot' the likelihood of you dying when in relative good health is slim, unless old young or an unfortunate 50%.

So I shouldn't have a morbid fear of these 'hotter' spp then just a healthy, respectful fear of them.

I'm going to keep reading up on other spp (I only keep Heterometrus, and Pandinus so far for the last 1.5yrs) to see what if any I might venture into next.

Thanks all for your insight on the LD50 figures...

Regards Thaedion
 

fusion121

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Hi
Definitely do treat them with respect, even a sting from a 2nd instar Lq is immensely painful (take my word for it), but you are pretty unlikely to die from a sting. Though in the case of the really hot species I would recommend seeking medical attention in the case of a sting from an adult, just to be on the safe side.
 

Nazgul

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Hi,

you should have in mind that every individual is reacting differently to venom, too.

also what may be "safe" for a mouse may not be so for a Homo sapiens
A good example is Hemiscorpius lepturus which doesn´t seem to be very harmful to mice according to the high LD50 value but is among the most dangerous spp for humans.
 

Brian S

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Hi,

you should have in mind that every individual is reacting differently to venom, too.


A good example is Hemiscorpius lepturus which doesn´t seem to be very harmful to mice according to the high LD50 value but is among the most dangerous spp for humans.
Very very good point Alex ;). I was stung last Fall by a Tityus bahiensis and although not much happened, I know it could make someone else really ill. I set up for 2 hours "monitoring" what was happening. I was really nervous at first as I didnt know what to expect. After 2 hours, I could tell that it wasnt going to get worse and I went to bed.
Like Oliver said, we need to treat all with respect even the less toxic species so we will be in the habit of using caution when we work with the others.
 

H. cyaneus

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I just go by if it's under 1 or 2 not to play with it. ;) All I need to know right now really.

Mike
 

intrinsic_scorp

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Added relevance

A few relevant points I would like to make is the amount of venom that is released, should a sting occur, can vary. Furthermore, the amount released will vary between instars as well. Finally, it is my understanding that scorpions can control the amount of venom they inject. While this information is partially subjective, there is available research on select scorpion species that you can find through searches conducted on the internet.

I would like to add one bit of pure speculation, though. Scorpions might be more likely to release increased venom during a sting if they are cornered or pinned. Dry stings are also an occurence I have read about.
 
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