Sv7887 From United States of America, joined May 2008, 1025 posts, RR: 0 Reply 1, posted (4 years 1 month 3 weeks 5 days 8 hours ago) and read 1343 times:
Quoting Mirrodie (Thread starter): Obama signed off on Embyronic stem cell research. Why?
It was a political payback to his backers..But of course you have to read the fine print with Obama:
"President Obama may have abolished contentious Bush-era restraints on federal funding of stem cell research on Monday, but a legislative obstacle still remains for scientists seeking more money.
A spending bill that Obama signed on Wednesday explicitly bans federal funding of any "research in which a human embryo or embryos are destroyed, discarded, or knowingly subjected to risk of injury or death," language that pertains to creation of new stem cell lines."
But the Dickey-Wicker provision still prevents federally backed researches from creating their own stem cell lines, blocking their access to hundreds of new embryonic stem cell lines, usually from embryos left over from fertility treatments that would otherwise be discarded. Scientists tout such promising, long-term research in hopes of creating better treatments, possibly even cures, for conditions ranging from diabetes to paralysis.
And what people forget is that only Government funding was restricted...We have a massive private sector in the United States that has far more spending power than the Federal Government. And of course, add the rest of the world to the mix.
What most who argue about this won't admit is that Bush's ban led scientists to discover skin stem cells could be made to act just like embryonic stem cells:
It's largely an issue of politics. Britain's top fertility expert seems to think embryonic stem cells research is largely overhyped in terms actual usefulness:
DocLightning From United States of America, joined Nov 2005, 16838 posts, RR: 57 Reply 2, posted (4 years 1 month 3 weeks 5 days 8 hours ago) and read 1336 times:
Quoting Mirrodie (Thread starter):
Aren;t we able to harvest the same stem cells, that is undifferentiated cells, from umbilical cord blood? If not, explain the differences.
No. There are two kinds of stem cells. Now, I'm digging WAAAY back into my graduate degree in molecular biology, which I finished in 2001, so I might say something a bit wrong here, but the overall message is correct.
Pluripotent stem cells are cells that usually serve no specific function of their own but can divide and differentiate into multiple different types of cells. So umbilical cord blood cells contain stem cells that can differentiate into different kinds of blood cells and a few other types, IIRC. However, you cannot turn an umbilical cord blood cell into, say, a neuron.
Totipotent stem cells are cells that can differentiate into any cell type found in that organism. So from gonads to neurons, a totipotent cell can give rise (sometimes through a few steps first) to any cell type that exists in that species.
You might next wonder why we can't simply somehow de-program a pluripotent stem cell into a totipotent stem cell. Well, we still don't completely understand what happens in a totipotent stem cell that stops it from being totipotent. It does have something to do with DNA modification and packing, we know that much.
We also know that it is possible to reverse the differentiation because gonads produce gametes (eggs and sperm) that combine to form an embryo, which is the first totipotent stem cell. As the sperm nucleus approaches the egg nucleus, a whole flurry of DNA modification happens that allows every single gene in the genome to be accessed. The embryo divides a few times to become a zygote, which is still a bunch of totipotent cells. Eventually, a sack of cells forms around an inner cell mass (ICM). The sack of cells is no longer totipotent; it becomes placenta and amniotic sack. The ICM is still totipotent embryonic stem cells. We can pull out a few of those ES cells and theoretically get them to grow into kidneys, bones, skin, neurons, or any other cell type that exists.
Now, slightly off-topic, but this particular point always sends chills down my spine:
Consider a liver cell. How did that liver cell get to be a liver cell? Let's trace its lineage. Liver cells in embryology come from the mesodermal layer of the embryo. The mesoderm is one of the first differentiations out of the ICM (along with the endoderm and ectoderm).
Now, the ICM comes from a sperm cell and an egg cell. The sperm cell and egg cell come from cells in the gonads. In other words, at no point in the entire lineage of that liver cell was there ever another liver cell. And that, to me, is an awesome and fascinating fact.
AznMadSci From United States of America, joined Dec 2007, 3542 posts, RR: 5 Reply 3, posted (4 years 1 month 3 weeks 5 days 5 hours ago) and read 1295 times:
Quoting Mirrodie (Thread starter): Aren;t we able to harvest the same stem cells, that is undifferentiated cells, from umbilical cord blood? If not, explain the differences.
Based on the stem cell lines that was allowed under Bush administration, they lost the essence of being a true pluripotent stem cell. These cells have been cultured in particular media that can alter it's nature. Thus the current in vitro studies done (in cell culture) would greatly differ than in vivo where the stem cells could be obtained from a "fresh" source. What's to be seen with the new legislation is if and how many new stem cell lines could be generated.
No. The Doc gave a good explanation. Many cell types have a "stem" cell such as skin. But those "stem" cells need need to come from somewhere.
Quoting DocLightning (Reply 2): In other words, at no point in the entire lineage of that liver cell was there ever another liver cell. And that, to me, is an awesome and fascinating fact.
To dig a bit deeper, my fascination is in the genetics and biochemistry that regulates the mechanism of cell division and proliferation during embryogenisis.
Quoting Sv7887 (Reply 1): It's largely an issue of politics. Britain's top fertility expert seems to think embryonic stem cells research is largely overhyped in terms actual usefulness:
Some might see it as overhyped. I still think it's untapped and we still don't know if in vivo studies will move forward to tackle many diseases and injuries. What will move research in the forward direction is the increase of research funding. In a few years, let's see if the research can change the opinions.
The journey of life is not based on the accomplishments, but the experience.
DocLightning From United States of America, joined Nov 2005, 16838 posts, RR: 57 Reply 4, posted (4 years 1 month 3 weeks 5 days 4 hours ago) and read 1277 times:
Quoting AznMadSci (Reply 3):
Some might see it as overhyped. I still think it's untapped and we still don't know if in vivo studies will move forward to tackle many diseases and injuries. What will move research in the forward direction is the increase of research funding. In a few years, let's see if the research can change the opinions.
The big issue is whether stem cells can be used to create, say, a kidney.
the problem with using stem cells to replace organs is that you need a beating heart to do it. And then you need a bunch of other signals to keep the cells growing, dividing, differentiating. A liver doesn't develop in a vacuum. A number of factors, some of them quite banal and pedestrian (like physically running into the bottom of the diaphragm) lead to the final shape and function of the liver.
Although they did manage to grow a human external ear on the back of a mouse, which is a start.
AznMadSci From United States of America, joined Dec 2007, 3542 posts, RR: 5 Reply 5, posted (4 years 1 month 3 weeks 5 days 3 hours ago) and read 1260 times:
Quoting DocLightning (Reply 4):
The big issue is whether stem cells can be used to create, say, a kidney.
I think we're expecting way too much for science to immediately say "let's regenerate a new kidney." How about regeneration at the tissue level?
The journey of life is not based on the accomplishments, but the experience.
Mirrodie From United States of America, joined Apr 2000, 7421 posts, RR: 65 Reply 6, posted (4 years 1 month 3 weeks 5 days ago) and read 1237 times:
Quoting DocLightning (Reply 2): Now, slightly off-topic, but this particular point always sends chills down my spine:
Consider a liver cell. How did that liver cell get to be a liver cell? Let's trace its lineage. Liver cells in embryology come from the mesodermal layer of the embryo. The mesoderm is one of the first differentiations out of the ICM (along with the endoderm and ectoderm).
Now, the ICM comes from a sperm cell and an egg cell. The sperm cell and egg cell come from cells in the gonads. In other words, at no point in the entire lineage of that liver cell was there ever another liver cell. And that, to me, is an awesome and fascinating fact.
Doc, thanks for the refresher. I haven't even thought about pluripotent cells in over 10 years. It always comes back to the basics and that was a complete review! LOL
Forum moderator 2001-2010; He's a pedantic, pontificating, pretentious bastard, a belligerent old fart, a worthless st
Continental From United States of America, joined Jun 2000, 5476 posts, RR: 21 Reply 7, posted (4 years 1 month 3 weeks 5 days ago) and read 1234 times:
Quoting AznMadSci (Reply 5): How about regeneration at the tissue level?
Yes, like a new set of beta cells in a diabetes patient.
Pilotsmoe From United States of America, joined May 2005, 248 posts, RR: 0 Reply 9, posted (4 years 1 month 3 weeks 4 days 23 hours ago) and read 1218 times:
Quoting Continental (Reply 7): es, like a new set of beta cells in a diabetes patient.
the beta cells are the easy part, they need to work out the autoimmunity issues(if were talking about type 1, type 2 diabetics need to stop eating junk food and exercise)
DocLightning From United States of America, joined Nov 2005, 16838 posts, RR: 57 Reply 10, posted (4 years 1 month 3 weeks 4 days 21 hours ago) and read 1196 times:
Quoting Continental (Reply 7):
Yes, like a new set of beta cells in a diabetes patient.
Working on it!
Quoting FLY2HMO (Reply 8):
So does that mean that what was first, the chicken or the egg, was in fact a stem cell? Big grin
As a biologist, we ask a more advanced question:
Is an egg a chicken's way of making another chicken?
Or... is a chicken an egg's way of making another egg?
AznMadSci From United States of America, joined Dec 2007, 3542 posts, RR: 5 Reply 11, posted (4 years 1 month 3 weeks 3 days 22 hours ago) and read 1130 times:
DocLightning From United States of America, joined Nov 2005, 16838 posts, RR: 57 Reply 13, posted (4 years 1 month 3 weeks 3 days 20 hours ago) and read 1113 times:
Quoting FLY2HMO (Reply 12):
Pfsh, now you're just messing with semantics and creating a paradox. Damn you. headache Wink
No, it's actually a rather profound question because it shows you that sometimes, things in Biology are not so obvious.
Yellowstone From United States of America, joined Aug 2006, 3071 posts, RR: 7 Reply 14, posted (4 years 1 month 3 weeks 3 days 18 hours ago) and read 1093 times:
One of the other upshots to embryonic stem cells that I don't think is possible with adult stem cells is the ability to couple that with cloning. If you can replace the genetic info in the fertilized egg with that of the patient, thus technically cloning the patient, the embryonic stem cells will not be rejected by the patient's immune system.
Hydrogen is an odorless, colorless gas which, given enough time, turns into people.
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