October Update

Bought a standard poodle puppy.  Bringing him home October 5, so October will be full of housebreaking, and FUN.



Entries in egg cell (3)


Does IVF Mean Playing God? I Don't Think So!

It’s strange that the Nobel Assembly took so long to award the Nobel Prize in Physiology or Medicine to Robert Edwards, the inventor of IVF (in vitro fertilization).  It’s been over three decades since the birth of Louise Brown, the first “test tube baby.”

         Maybe the moral questions that arose with Louise’s arrival held the Nobel Prize back all those years.  Some of the moral questions had to do with potential harm to the mother through use of hormones to harvest multiple egg cells or to make her uterus hospitable to implantation.  Some had to do with humans possibly playing God by causing conception in a Petri dish.  Another question posed in a CBS News story about the Award yesterday was whether it’s appropriate to obtain stem cells from embryos created through IVF.

         I’ve been thinking about the “humans playing God” question.  I believe this question vastly diminishes God and vastly inflates human beings. 

         It’s true that we are the only animal that learns and practices science, but there’s an infinite distance between practicing science and playing God. 

         To me, what Robert Edwards figured out was a godly way for some infertile couples to be able to have babies.  He used what God provided, the miracle of conception and his own miraculous human brain, and invented a method for bringing together an egg and a sperm that otherwise couldn’t join even though potential parents passionately wanted the baby that could come from the joining. 

         Edwards cooperated in this with Patrick Steptoe, an obstetrician and gynecologist.  It was Steptoe who figured out how to administer hormones to a consenting, adult mother, to harvest her egg cells and ready her womb for an embryo.  I can’t imagine God objecting.

         As for the stem cell question, it’s a by-product of our ability to use God’s miracles to bring wanted babies into the world.  Here’s another use for our brains; we need to come together in peace and goodness to work out moral guidelines for what may turn out to be another heavenly gift.


Mysteries of Cell Migration

A few months ago (July 6) I wrote about how cells gather together to create multicelled organisms or multicelled organs.  Now I’ve come across a film of a marvelous experiment showing cells gathered together and “following the leader” in cell migration.

         Here it is, a lovely example of how new techniques for genetically engineering cells can be used to learn something about how cells actually work together.

          The film shows moving border cells inside a fruit fly egg chamber.  Normally, these cells migrate together, and the researchers want to learn how this happens.  So they have engineered the cells to make a protein, called “Rac” that is light sensitive.  Whichever cell in the group has the largest quantity of Rac becomes the leader, and follows the researcher’s light.  All the other cells move right along with this lead cell.

         How amazing and wonderful.  I hope these researchers will keep learning about this.  But just the fact of the leader being the one with the most of a certain protein seems magical and mysterious enough.


"M" Is for the Million Things She Gave Us

In a follicle in the body of a maternal fruit fly or mouse or human being lies an egg cell.

This egg cell is immense compared to the sperm that may eventually fertilize it. A sperm must race vast distances to arrive at the egg in time to compete with millions of other sperm for the fertilization prize, the chance to pass its genes to future generations. So a sperm carries only necessities: a nucleus with the genes packed into chromosomes, high energy molecules and energy-releasing structures to power the long race, a flagellum to swim with, enzymes to dissolve the egg’s protective covering and to signal that this sperm is now fertilizing the egg, and no other sperm may enter.

Once fertilized, the egg cell will divide repeatedly to produce a hollow ball of many identical cells, which will then layer themselves to start developing into an embryo. These early cell divisions happen so fast, the new cells have no time to grow before they divide again. Therefore, except for their chromosomes, which duplicate in full sets before each division, the new cells’ substance and internal structures are all portions of the original egg. So a mother animal must produce an egg large enough to provide all this material.

Next, how do the hundreds of identical new cells wind up becoming different parts of an embryo? How do they turn into head, middle, tail, top, bottom, sides, limbs? We don’t know for sure, but certain clues suggest that the maternal reproductive system conveys this body architecture. Before the egg cell leaves the follicle, molecules from the mother’s body diffuse into it. These molecules are concentrated at one side of the egg, so when the fertilized egg repeatedly divides, some of the new cells will contain a lot of the maternal molecules, and some will contain few or none. So already, the many new cells are not identical. Inside the new cells which contain them, the maternal molecules may produce proteins, and the proteins may signal the new cells to specialize in being the head-end of the embryo. Once these head-end cells specialize, they manufacture their own signals to send to other new cells farther downstream in the incipient embryo, telling them to become the embryo’s mid-section. Then the mid-section cells signal the tail-end cells. Once all these groups of cells start to specialize, they can signal within the group for finer and finer anatomical details.

So like it or not, we owe a lot to Mom.