Thoughts on this? I, for one, think it is quite interesting and am glad researchers have been given the ok.


BBC NEWS | Health | 'Human-animal' embryo green light

__________________
There can be no bystanders in the battle for survival. Anyone who will not fight by your side is an enemy you must crush.

We are at war with forces too terrible to comprehend. We cannot afford mercy for any of its victims too weak to take the correct course. Mercy destroys us; it weakens us and saps our resolve. Put aside all such thoughts. They are not worthy of those in the service of country.

I beleive this is about the process of using human DNA in an 'emptied' animal oocyte to create stem cell lines. It isn't at all suprising that this method is being explored, given the difficulty of obtaining human oocytes or embryonic (totipotent) stem cells.
One thought I have about this is the concern that these particular lines, while they may may be a real boon for basic research, should perhaps not be used for therapy. Even an 'emptied' animal cell contains mitochondria, which have their own DNA. Since we don't have any way of identifying 'silent' endogenous retroviruses, we can't say whether any could be lurking in the mitochondrial DNA of another species, or how they might behave in a new environment. This is essentially the same concern I have regarding xenotransplantation. I really don't know of any animal mitochondrial viruses, but there are fungal mitochondrial viruses, so it's a possibility; though perhaps less of a threat than the reality of nuclear endogenous retroviruses in transplant tissues composed of whole nonhuman animal cells.

__________________
please click and help the eggs hatch!

"The only abnormality is the incapacity to love"
-Anias Nin

I agree that this is only to facilitate basic research rather than for therapeutical purposes for some of the reasons you've stated. Advancing basic reasearch is a plus in my book, too.

__________________
I am an American. That's the way most of us put it, just matter of factly. They are plain words, those four: you could write them on your thumbnail, or sweep them clear across this bright autumn sky. But remember too, that they are more than just words. They are a way of life. So whenever you speak them; speak them firmly, speak them proudly, speak them gratefully. I am an American. ...a tradition

Oh, it certianly is! And one thing that drives me nuts is the way much of this field is misconstrued, sometimes it seems deliberately, to sound like people are breeding human-sheep hybrids for their secret army, or something. I suppose it sells more papers than the actual science would, though I can't help but think that if it were explained better the real discoveries are much more exciting than any science fiction/ horror plot.

I do have real concerns about endogenous retroviruses, though, when things start to move towards therapeutic trials. I don't know that animal mitochondria (as in the article above) are as much of a risk, but there's a company near here that is working on developing a line of pigs with cell surface antigens that would not be rejected by the human immune system, and they worry me. Far better to make organ donation the default, so that people who don't want to donate organs must opt out, rather than the reverse. Humans are basically lazy, so I bet this would increase the organ pool considerably.

__________________
please click and help the eggs hatch!

"The only abnormality is the incapacity to love"
-Anias Nin

[Emphasis mine] Ain't that the truth 100% of the time!
I am soooo for the opt-out method of determining organ donors.

I personally am pleased that the alpha-gal antigen has been addressed to some extent with xenotransplantation using pigs. I have to think they they are taking into consideration the possiblity of mitochondrial retroviruses, but I am not familiar enough with the current research in this area to know for sure. Would you mind sharing what company has announced this so that I can look at it?

We have been using porcine cartilage for quite some time in humans. As I am not a biologist, does the treatment (I don't know what method of treatment they use) of this cartilage destroy mitochondrial nucleic acids?

On our (chemists) end, we continue to work on drugs to inhibit the immune response to alph-gal, but this would not get around the risk of retroviruses at all; rather it's a band-aid procedure to allow for xenotransplatation.

__________________
I am an American. That's the way most of us put it, just matter of factly. They are plain words, those four: you could write them on your thumbnail, or sweep them clear across this bright autumn sky. But remember too, that they are more than just words. They are a way of life. So whenever you speak them; speak them firmly, speak them proudly, speak them gratefully. I am an American. ...a tradition

I applaud advancement in science.

__________________
"Give me your tired, your poor,
Your huddled masses yearning to breathe free,
The wretched refuse of your teeming shore.
Send these, the homeless, tempest-tost to me,
I lift my lamp beside the golden door!"

Yes, I've read a very little about alpha-gal; retroviruses are a whole seperate issue, really, and they might not be a real issue at all; but we don't know. The company is called Revivacor...or at least, they were; they changed their name recently, but I can't recall to what. I'm only familiar with them because they send some of their pigs to the vet hospital, and I've done necropsies for them, ocasionally. I don't think they've gotten to the point of announcing any breakthroughs, but of course they don't tell us exactly what they are doing with the pigs. And it really would be nice to know if we were working with a genetic knockout, of something like that, when trying to make a diagnosis (grumble).

I don't know what they do to xenotransplanted cartilage, but those cells are so terminally differentiated that I'd think that they'd be much less permissive for viral replication. At least I hope so. iIf they destroyed the nucleic acids, the cells would be dead; which I don't think would work. The same with heart valves; those cells don't divide, which is why we have to find some other way to replace the tissue, but it also means that the replicative machinary isn't there. I'm just speculating, though; we don't do any of it (except sometimes skin grafts, but those are autologous) in veterinary medicine, so my knowedge of xenotransplantation is not really much above an interested laypersons level. Studies looking for endogenous retroviruses in human recipients have'nt found any (Search for Cross-Species Transmission of Porcine Endogenous Retrovirus in Patients Treated with Living Pig Tissue -- Paradis et al. 285 (5431): 1236 -- Science, but one of the authors of that papar (O'Rourke) works as a clinical pathologist in our department now, and muchof my concern in this area comes from conversations I've had with her. I'm sure there's more recent work in that area, but I'm at home so I don't have access to the universities subscriptions here.

__________________
please click and help the eggs hatch!

"The only abnormality is the incapacity to love"
-Anias Nin

Thanks for the info! My interest is not much above the layperson's either. I just keyed into the alpha-gal aspect because a freind of mine works on that.

I have to think that the pigs that get sent to you are the result of tests on knockouts. Since alpha-gal is the biggest roadblock to porcine xenotransplantation when considering surface antigens, that would make the most sense. As you said, though, knowing what you are looking at would be greatly helpful, but I imagine they would not be willing to share too much with anyone at this point since these pigs may not yet be ready for market. (My mind has suddenly focused on my toes..."this little piggie went to market"...random thoughts )

Again, thanks for the info. I'll check this out when I get back to work as I don't have subscription access at home either.

__________________
I am an American. That's the way most of us put it, just matter of factly. They are plain words, those four: you could write them on your thumbnail, or sweep them clear across this bright autumn sky. But remember too, that they are more than just words. They are a way of life. So whenever you speak them; speak them firmly, speak them proudly, speak them gratefully. I am an American. ...a tradition

I disagree on this issue simply because there is no such thing as basic research.

Planet of the Apes anyone !

__________________
Anyone who thinks freedom comes cheap, please put the blindfold on and stand against the wall.

Many times I believe Americans will have to take back the country and start a new government.

Basic research is what happens before you (the public) sees anything. As in answering the questions about how a biological system works. This must happen before we even know what things might work to modify it in ways that benefit people, but has no direct relation to any eventual treatment. For example, much of the basic research that revealed what diabetes actually *is* was done with dogs, but insulin used for treatment is mostly recombinant human, now.

Like I said, the real discoveries are much more exciting than any science fiction plot.

__________________
please click and help the eggs hatch!

"The only abnormality is the incapacity to love"
-Anias Nin

I whole heartily agree......I guess that perhaps I've simply lost too much faith in the human race to do good, I just have this sick feeling of what science will try to do.

Call me paranoid.

__________________
Anyone who thinks freedom comes cheap, please put the blindfold on and stand against the wall.

Many times I believe Americans will have to take back the country and start a new government.

I think it's rather normal for a person who is not involved in the scientific research community to be a bit paranoid because of science fiction and media drama - this drama sells. Believe me, if scientists were mad, as the science fiction material and press tend to promote from time to time, we wouldn't be here discussing this.

If a scientist were interested in unethical practices or in wanton evil, the scientific community would ensure that they never get a penny to further their research. If that weren't the case, the damage an out-of-control scientist could do would be scary because of the knowledge they possess. We are excellent at policing quacks.

__________________
I am an American. That's the way most of us put it, just matter of factly. They are plain words, those four: you could write them on your thumbnail, or sweep them clear across this bright autumn sky. But remember too, that they are more than just words. They are a way of life. So whenever you speak them; speak them firmly, speak them proudly, speak them gratefully. I am an American. ...a tradition