more on thimerosal

[purslaine]

http://www.ncbi.nlm.nih.gov/pubmed/22658806.1

[Taximom5]

Originally Posted by kathymuggle 

http://www.ncbi.nlm.nih.gov/pubmed/22658806.1

That link just redirects me to a "Welcome to PubMed" page--no study, no info.

Try again? Or quote the abstract of the study you found?

[ma2two]

Originally Posted by Taximom5 


That link just redirects me to a "Welcome to PubMed" page--no study, no info.
Try again? Or quote the abstract of the study you found?

That's weird. It worked for me.

[katelove]

I got the same page as Taximom.

[purslaine]

Huh.  I clicked the link - it worked for me.

Here is the title:

Prenatal exposure to organomercury, thimerosal, persistently impairs the serotonergic and dopaminergic systems in the rat brain: Implications for association with developmental disorders.

Here is another link to the abstract - I don't know if anyone can get at the full text:

http://www.sciencedirect.com/science/article/pii/S0387760412001180

Edited by purslaine - 6/11/12 at 7:05pm

[Taximom5]

Thanks, Kathy--that one worked.

Holy heck. I'm amazed--not at the abstract or conclusion, but that they managed to get it published.

Maybe science is finally on the right track....

[Taximom5]

Before they bury this one:
Prenatal exposure to organomercury, thimerosal, persistently impairs the serotonergic and dopaminergic systems in the rat brain: Implications for association with developmental disorders
Michiru Ida-Etoa, , , Akiko Oyabua, Takeshi Ohkawaraa, Yasura Tashiroa, Naoko Naritab, Masaaki Naritaa
a Department of Anatomy II, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan
b Department of Education, Bunkyo University, Koshigaya, Saitama 343-8511, Japan
Received 8 November 2011. Revised 2 May 2012. Accepted 3 May 2012. Available online 1 June 2012.
http://dx.doi.org/10.1016/j.braindev.2012.05.004

Abstract
Thimerosal, an organomercury compound, has been widely used as a preservative. Therefore, concerns have been raised about its neurotoxicity. We recently demonstrated perturbation of early serotonergic development by prenatal exposure to thimerosal (Ida-Eto et al. (2011) [11]). Here, we investigated whether prenatal thimerosal exposure causes persistent impairment after birth. Analysis on postnatal day 50 showed significant increase in hippocampal serotonin following thimerosal administration on embryonic day 9. Furthermore, not only serotonin, striatal dopamine was significantly increased. These results indicate that embryonic exposure to thimerosal produces lasting impairment of brain monoaminergic system, and thus every effort should be made to avoid the use of thimerosal.

[prosciencemum]

Originally Posted by Taximom5 

Before they bury this one:
 

I'm curious who you think "they" are - I guess pharmaceutical companies? But "they've" already removed thimerosol from all shots for newborns, and pregnant women can request thimerosol free flu shots (and are recommended to do so in most cases), so what benefit would burying this have? 

I don't have access to the text. 

 I looked up some definitions, as a lot of that abstract was pretty dense scientific language, and I would like to understand what this study is and the significance of it if I can. 

So: 

serotonergic development 

(From wikipedia) Serotonergic means "related to the neurotransmitter serotonin". A neurotransmitter is a chemical which sends signals from your brain to your cells to tell them what to do. Serotonin is one of these, and "It is popularly thought to be a contributor to feelings of well-being and happiness.". 

So this statement "serotonergic development" means the development of the chemical which helps transmit feelings of well being (or way too oversimplified?). 

hippocampal serotonin

(Again wikipedia - I love it!). 

The hippocampus is a part of the brain.  It's the bit which relates to long/short term memories and is often found  to be damaged in people with Alzaimers/memory loss. So this is serotonin (see above) found in that part of the brain. 

 So an increase in serotonin in this part of the brain means what? 

striatal dopamine

The striatum is another part of the brain. It seems to mostly have to do with planning movement, but also can have a link to memory function. Parkinsons and Huntington's disease seem to be linked to damage in this area. 

Dopamine is a chemical in the body. It's main function is in reward benefits - a lot of recreational drugs increase dopamine which feels really nice, so that gets addictive. 

So an increase in dopamine in the striatum.... what does that mean? 

brain monoaminergic system

So monoaminergic seems to be a collective term for things like serotonin and dopamine - these chemicals which transmit information in the brain. 

So the conclusion is thimerosol injected into rat embryos causes them to develop these chemicals differently than the rats which didn't have this. 

I can't see the full text, but I can see the caption of the first figure, which implies all the pregnant rats in the study had thimerosol injected. One group had 0.1 mgHg/kg and the other 0.01 mgHg/kg, and they refer to the latter as the control. Am I misunderstanding that?

"Fig. 1. Monoamine levels in control vs. thimerosal-exposed rats (ng/g weight). Different doses of thimerosal (0.1, and 0.01 mgHg/kg) were administered to E9 pregnant rats, and then allowed to have pups. On P50, concentrations of hippocampal serotonin and striatal dopamine were measured by HPLC. Values are mean ± SEM. ^∗p < 0.05 vs. control;^∗∗p < 0.01 vs. control."

The four types of flu vaccine in 2011/2012 which contain thimerosol contain 0.025 mgHg per dose (http://www.cdc.gov/flu/protect/vaccine/vaccines.htm)  - for a typical pregnant woman weighing 70 kg, that works out to 0.0004 mgHg/kg for pregnant women. So they have less thimerosol than the control in this study. Think I might have found my reason not to worry about it (well apart from the fact that you can avoid all thimersol now if you wish). 

Still it was interesting learning/reminding myself of all those biology words, so thanks for posting it. :) 

[nukuspot]

Some places pregnant women had been/will be offered thimerasol containing vaccines are: Flu shots (especially last years H1N1 shots). Many, many pregnant women do not know to advocate for themselves to get a preservative free shot. Anecdotally (working in the midwifery world and having many preggie friends) I have first hand experience to that fact. I know many pregnant women who had no idea some flu shots had thimerasol in them. Two: If a pregnant woman goes into the ER with a deep wound they will usually offer Tdap for a tetanus booster...Usually. But some women will be offered adult Td or TT (or have to request them due to previous reactions to the pertussis component of the combined shot, and both have thimerasol in them. A few weeks ago there was a post from a BF mama who had that same situation. Good thing she wasn't pregnant...

So yes, most pregnant women will not come into contact with thimerasol, but a handful will. And IMO, even one prenatal exposure is unacceptable.

[prosciencemum]

Sure, but did you see the end of my post - the control sample in the rats were given 25 times more thimerosol than is in the flu shots with thimerosol (when corrected for typical body weight). The ones who showed an effect relative to those controls were given almost 250 times the amount which is in the flu shot with thimerosol. So pregnant rats given 250 times the amount of thimerosol in the thimerosol containing flu vaccines show effects relative to those given 25 times the amount in the thimerosol containing flu vaccines.  

Unless I did my maths wrong because it's bedtime. 

I don't know the thimerosol content of the tetanus shots.  

I also don't really understand the significance of the effects they saw. I'd love someone more up on brain biology to chime in. :) 

[katelove]

There is still so much we don't know about brain functioning but serotonin and dopamine disruption have been linked to SIDS, Parkinson's diseases, schizophrenia, depression and anxiety disorders. I suspect there are more but those are the ones I know of.

Have you ever searched the primal health research database? This is the sort of research they are compiling.

[nukuspot]

I wasn't responding to the link (haven't had time to read it, packing for a trip) just to the claim that it is easy for a pregnant woman to avoid thimerasol. But without reading anything, and my own anti-animal testing feelings aside, rat studies do not equal human studies. Lab rats aren't kept alive long enough to observe them for long term effects, and behavioral changes would be quite hard to discern in rats, unless they were severe. So I think a lot of things could get overlooked. The adult TT has a full 25 mcg dose of thimerasol. I don't know about the adult Td, I think it's the same but not 100% positive.

[ma2two]

Sometimes even when people request thimerosal free flu shots, they still get the thimerosal without knowing it. I was at a drugstore when they were having a flu shot clinic. I asked the nurses giving the shots if they had mercury. They swore to me that they didn't. They couldn't believe it when I pointed it out in the package insert. And yes, they were multi-dose vials. This was Mollen Immunization Clinics, which gives flu shots nationwide.

[Taximom5]

Originally Posted by prosciencemum 

Sure, but did you see the end of my post - the control sample in the rats were given 25 times more thimerosol than is in the flu shots with thimerosol (when corrected for typical body weight). The ones who showed an effect relative to those controls were given almost 250 times the amount which is in the flu shot with thimerosol. So pregnant rats given 250 times the amount of thimerosol in the thimerosol containing flu vaccines show effects relative to those given 25 times the amount in the thimerosol containing flu vaccines.  

Unless I did my maths wrong because it's bedtime. 

I don't know the thimerosol content of the tetanus shots.  

I also don't really understand the significance of the effects they saw. I'd love someone more up on brain biology to chime in.  

Since thimerosal crosses the placenta, I don't think the pregnant woman' body weight is the issue here; it's the fetus that is at risk for the neurological effects.

[Taximom5]

Originally Posted by ma2two 

Sometimes even when people request thimerosal free flu shots, they still get the thimerosal without knowing it. I was at a drugstore when they were having a flu shot clinic. I asked the nurses giving the shots if they had mercury. They swore to me that they didn't. They couldn't believe it when I pointed it out in the package insert. And yes, they were multi-dose vials. This was Mollen Immunization Clinics, which gives flu shots nationwide.

Your experience is not unique. Many medical professionals are unaware that multi-use vaccine vials are preserved with thimerosal.

[prosciencemum]

Originally Posted by Taximom5 


Since thimerosal crosses the placenta, I don't think the pregnant woman' body weight is the issue here; it's the fetus that is at risk for the neurological effects.

OK. But even then - the rat fetus is clearly much smaller than the human fetus. My best guess - about the same ratio in weight between the pregnant rat and a human, and a rat and human fetus, but I have no actual information!

nukuspot - I totally agree animal studies may not translate to identical human effects.  

25 mcg is the same amount of thimerosol per dose in the multi-vial flu shots, so all my maths works for that vaccines too. :) 

[ma2two]

Originally Posted by prosciencemum 

25 mcg is the same amount of thimerosol per dose in the multi-vial flu shots, 

There is 25 mcg mercury per dose, not 25 mcg thimerosal.

[prosciencemum]

Originally Posted by ma2two 

There is 25 mcg mercury per dose, not 25 mcg thimerosal.

 Oh right. Is that was the mgHg units mean - micro grammes of mercury, in the study we're discussing. In which case I used lazy language, but I think I was comparing the right sets of numbers. Thanks for the clarification. 

[ma2two]

Originally Posted by prosciencemum 

Is that was the mgHg units mean - micro grammes of mercury, in the study we're discussing. 

No, mg means milligram. mcg means microgram. 1 mg = 1,000 mcg.

[prosciencemum]

Originally Posted by ma2two 

No, mg means milligram. mcg means microgram. 1 mg = 1,000 mcg.

You're quite right. I'm not doing myself favour with the maths am I. That's what I meant. I was coming to edit. But the mgHg means milligrammes of mercury? 

In any case the rat study control is 0.01 mgHg/kg, while the high sample is 0.1 mgHg/kg. 

This compares to 25mcgHg per dose of flu shot (where there is any), which for a 70kg woman is 0.0004mgHg/kg (converting mcg to mg to give 0.025 mcgHg and dividing by 70kp for 0.004mgHg/kg). 

 So I did the maths right, even if I write it down wrong! ;)