Obama's E.O. on lifting Embryonic Stem Cell ban is driving AURaptor crazy! by AURaptor

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Obama's E.O. on lifting Embryonic Stem Cell ban is driving AURaptor crazy!

POSTED BY: AURAPTOR
UPDATED: Wednesday, April 1, 2009 13:36
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Wednesday, April 1, 2009 5:08 AM

I have a vote and I'm not afraid to use it!

"Though... Has something changed since 1987 that renders the results no longer applicable?"

Home pregnancy kits ?

Fast, accurate, reliable pregnancy tests that can be done in the doctor's office at the time of the visit ?

DUH !

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Wednesday, April 1, 2009 6:47 AM

BYTEMITE

Those weren't around in 1987?

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Wednesday, April 1, 2009 9:20 AM

BYTEMITE

"...the first home test kit for hCG was released in the mid-1970s."

http://en.wikipedia.org/wiki/Home_pregnancy_test

So... not so "duh."

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Wednesday, April 1, 2009 10:06 AM

RUE

I have a vote and I'm not afraid to use it!

AH ! I was HOPING someone would ask.

Back then, the home test was insensitive (one had to wait a minimum of two weeks after the first missed period), lengthy (hours rather than minutes), fraught with potential for error (a small amount of vibration like from a refrigerator could produce a negative result), difficult to interpret (many instances of results that were not clear-cut), and subject to a large negative error (only 85% accurate under IDEAL conditions in a non-pregnant result).* In addition, test results needed to be confirmed in a doctor's office (or hospital or clinic). Those 'official' tests were blood-based tests that needed to be sent to a laboratory, turnaround for the results was up to two weeks. It required a revisit to the doctor (or hospital or clinic) to get the results. The doctor (or hospital or clinic) would then do a pelvic exam to determine fetal size, therefore, approximate fetal age and date of conception.

Given that one or more missed periods is a common event, and that early pregnancy swelling may not be detectable, 'quickening' - the feeling of fetal movement which may start around g 4 months - may be the first and only distinct indication of pregnancy a woman has absent diagnostic confirmation.

* The test was based on red cells that had been coated with antibodies to HCG the 'pregnancy' hormone (the beta unit, to be specific). It was used to test urine.

During pregnancy, HCG is produced, and then lost with urine. So the first question is - how sensitive is the test ? At the time the test was relatively insensitive, in order to have a measurable amount of HCG, one had to wait at least 2 weeks after the first missed period (or, roughly, for the fetus to be one month old, or more).

Generally the highest urine HCG levels are early morning levels when the urine is most concentrated. So, the woman needed to collect the first urine of the day. Secondly, it needed to be a fresh specimen, as saved, even refrigerated urine might have produced a false negative result. So the woman needed to run the test that very morning.

If the woman had HCG in her urine, the HCG antibodies on the red blood cells would cross-link to the HCG and to other red blood cells. These cross-linked red cells settled differently than cells which were not cross-linked. Since it depended on red cells slowly settling out under gravity, the test took 2 hours - a lengthy amount of time compared to today.

As these matrixes of red cells were fragile, even a small amount of vibration could break them apart - for example, picking up the test stand and carefully setting it down again, or placing it on a counter next to a refrigerator, or on the toilet tank top and then flushing the toilet.

Finally, there were many instances where the cells settled in such a way that it looked neither positive nor negative. (I tried to find photos on google but I couldn't).

Suffice to say that the tests had a bad reputation among women as being expensive, time consuming and, worst of all - unreliable.

In actual practice, they were barely above chance at detecting pregnancy.

So, while these tests existed, they were not a useful tool for detecting pregnancy.

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And yes, it is a DUH !

Only an ignorant person - like ahem ! you - would go forward with such an uninformed opnion.

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Wednesday, April 1, 2009 10:32 AM

RUE

I have a vote and I'm not afraid to use it!

I wanted to add that the tests have moved forward with technology.

One BIG step forward was the use of monoclonal antibodies - and those are a very modern invention indeed. Their use improved sensitivity and reduced both the positive and negative errors at earlier and earlier stages of pregnancy.

The use of different indicators - not sheep red blood cells settling in a test tube - also improved the usability and reliability of these tests.

A lot more information into the reliability of these tests has improved the knowledge of whether these tests are being used appropriately, and how and when they fail (and ALL tests fail at some point.)

These tests are now being used as primary tests in doctors' offices, resulting in faster confirmation.

The use of ultrasound rather than manual exam provides for more accurate determination of g fetal age.

AND - both the chemistry improvements and clinical improvements have led to cross-improvements between them.

The situation today is FAR different from the one 20 or more years ago.

Finally - thanks to home pregnancy tests paving the way, different home test kits have been developed for other concerns.

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ETA - biological measurement isn't magic. It's based on particular and sometimes peculiar techniques and materials, with their own strengths and shortcomings. Breaking it down into its details makes it, I hope, more concrete and understandable, and not quite so 'out there' esoteric.

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Wednesday, April 1, 2009 11:31 AM

BYTEMITE

Which opinion, that Home Pregnancy Tests were available in the 1970's (if inaccurate, thank you for explaining), my opinion on abortion, or my question about what has changed in the field to render the results of that study inaccurate?

Or all of the above?

Remember that thing I said about never planning to get pregnant? I've never claimed to be an expert on this issue. I do seem to be less informed, as you seem to be more familiar with uncommon knowledge.

EDIT: this was in response to the post before your last. Breaking down the information, as you have, has been very helpful for me to understand how the situation at least for detecting pregnancy and determining how far along the pregnancy is has changed.

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Wednesday, April 1, 2009 11:45 AM

RUE

I have a vote and I'm not afraid to use it!

"my question about what has changed in the field to render the results of that study inaccurate"

That part.

"Breaking down the information, as you have, has been very helpful ..."

Chemistry, biology, medicine, measurement - my arena for many decades. I'm glad I could impart a little history.

And I really, really want people to understand that this is not magic. Mostly, it's someone's time consuming work to find the picky set of details, the specific materials and the right techniques to make these measurements happen. Sheep red blood cells ? Could it GET any stranger and, at the same time, more mundane ? But there it is.

I want to encourage people to look behind the curtain. You'll find real stuff there.

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Wednesday, April 1, 2009 1:13 PM

AURAPTOR

America loves a winner!

When are folks going to grow the hell up?

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Wednesday, April 1, 2009 1:36 PM

RUE

I have a vote and I'm not afraid to use it!

So, since I haven't seen anything that convinces me to the contrary, what I take from here is this:

There are three kinds of stem cells
adult
embryonic
embryonized (DNA modified).

Adult stem cells can fuse with other cells to help them along but cannot become those other cells and replace them. Sources of adult stem cells are limited by the amount of tissue you can remove and the type of tissue you are trying to help. (It makes little sense to remove most of a brain to try and find a few cells to treat Parkinson's for example. Or to remove most of a heart to try and find cells to treat the Purkinje fibers.)

Embryonic stem cells have the potential to become the cells you need them to be. Due to a lack of large-scale research however, their limitations and potentials are unexplored. Their sources are IVF clinics. They are taken from fertilized eggs at a very early stage of development - before any differentiation has taken place.

Embryonized stem cells are a total unknown. They are created by adding 4 genes to adult cells to cause them to behave differently.

Making federal money available for embryonic stem cell research does not mandate research, nor does it mean money will be spent on the research.

In general, federal spending on 'blue sky' research adds information, and in turn technologies, that would not generally be done by private profit-maximizing industry (Bell Labs and IBM excepted).

Is this a fair summary so far ?

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