Incentives for Organ Donations

There are now over 100,000 patients waiting for an organ transplant. Over 6,000 of them will die this year because they will not find a suitable organ in time. The problem, as discussed in Human Biology 5th ed. (pp. 368-369), is simply too few available organs for too many patients. Aside from the fact that finding a good match among unrelated donors is relatively rare, healthy people are often reluctant to donate an organ for emotional reasons and there is no financial incentive for organ donations. In fact, current federal law states that a person can go to jail and be fined $50,000 if “valuable consideration” is given to a donor. The law was meant to discourage commercial trafficking in human organs (considered to be exploitive of the poor), but it has also had a chilling effect on altruistic giving.

But that may soon change. Senator Arlen Specter of Pennsylvania will introduce a bill next year that would allow states to offer certain “incentives” to donors and their families, such as tax credits, contributions to 401K retirement plans, and tuition vouchers. The bill still would still prohibit the direct buying and selling of organs, however, so you won’t be able to buy a kidney on eBay any time soon.

One patient’s emotional odyssey as her kidneys began to fail is described in “Desperately Seeking a Kidney” published two days ago in the New York Times. It might make an interesting additional reading assignment for your students.

Frozen Embryo Dilemma

Fertility treatments and IVF procedures generally produce more viable embryos than are needed in order to achieve a successful pregnancy. So after a couple has a child by IVF, they must decide what to do with the “leftover” embryos. There are at least five choices: 1) freeze and save them for several years in case they choose to have more children, 2) discard them, 3) donate them for research, 4) donate them to another couple, and 5) leave them frozen until some other decision is made.

A recent survey published in the journal Fertility and Sterility (online Dec. 5) indicates that the decision is a difficult one, even for couples that do not want any more children. Over 40% would not feel comfortable discarding the embryos. And even though they no longer needed them for themselves, over 50% would not consider donating their embryos to another couple. Common reasons given were because they wouldn’t want their child brought up by another couple or because of the fear that their child might meet an unknown sibling someday. Forty percent would consider donating their unused embryos for research, but that option is not available at all IVF clinics. Faced with what they view as unacceptable options, twenty percent say they will keep the embryos frozen indefinitely. However, frozen embryos may not be viable after several decades, so this may ultimately be a decision to let the embryos die.

There are now more than 400,000 frozen embryos at IVF clinics. The authors of the survey suggest that potential parents need to be counseled thoroughly about the choices ahead of them before they choose IVF, not after.

What would your students choose to do if they had leftover embryos?

Alzheimer's Disease Linked to a Virus

Alzheimer’s disease is a debilitating disorder of the elderly characterized by severe, progressive loss of memory, confusion, irritability, and withdrawal. The disease develops because amyloid plaques accumulate in the brain, interfering with neural transmission. But why do these plaques develop in some elderly persons but not others?

A recent paper in the Journal of Pathology (217:131-138, Jan. 2009) offers some tantalizing clues. It appears that two factors may be involved; 1) a genetic predisposition to Alzheimer’s disease, and 2) chronic infection of the brain with the same virus that causes cold sores; Herpes simplex type 1. The herpes virus is present in the brains of a high proportion of elderly persons. In the absence of the genetic predisposition to Alzheimer’s the virus doesn’t seem to do much. But in elderly patients with the genetic risk factor for Alzheimer’s, the virus is associated with amyloid plaque accumulation and may in fact be the cause of the plaque formation. If this turns out to be correct, Alzheimer’s disease may some day be preventable with a vaccine.

I am reminded of another chronic disease - peptic ulcers - that turned out to be caused by an infection, in this case by a bacterium called Helicobacter pylori (see Human Biology, 5th ed., p. 328).

Re-creating Extinct Animals

According to a recent article in the New York Times, advances in DNA sequencing and genetic engineering techniques are leading to cautious optimism among scientists that someday it may be possible to bring extinct animals back to life. But it will not be easy. DNA undergoes decay after death, falling apart into little pieces within about 60,000 years. Determining the correct sequence of an extinct species’ DNA requires special DNA sequencers that can analyze the tiny pieces and then calculate how they were aligned in the original intact molecule.

The second step would be to actually reconstruct the deciphered DNA code back into intact DNA once again. One way would be to “reverse engineer” the DNA of a close living relative species until it is similar to the known sequence of the extinct species. So far this has not been possible because of the sheer numbers of base pairs (perhaps half a million) that would need to be modified. But researchers are hopeful that techniques will be available soon to modify up to 50,000 sites at a time. The extinct species’ DNA would then be inserted into an egg of the living relative and incubated in that relative until birth.

How would your students react if it were to be announced one day that an extinct human such as a Neanderthal had been reverse engineered and then born to a modern human or a primate mother?!

Ginkgo Doesn't Prevent Dementia

According to a study in the Journal of the American Medical Association, daily doses of the popular herbal antioxidant Ginkgo biloba neither prevent nor delay the onset of dementia (cognitive impairment). The most common type of dementia is Alzheimer’s disease.

Herbal extracts of Ginkgo remain popular as a memory enhancer, even though previous scientific evidence showed that Ginkgo just doesn’t enhance memory. So don't expect this latest finding regarding dementia to put much of a dent in Ginkgo’s annual sales of over $200 million. Good marketing apparently trumps good science.

Surrogate Grandmother

According to an Associated Press article that appeared in many major newspapers and news services yesterday, a 56-year-old woman gave birth last month to triplets. The event was noteworthy because the three baby girls were actually her biological granddaughters.

Apparently a young couple could not conceive because the woman had had a hysterectomy. So they used in vitro fertilization (IVF) to produce their embryos, which were then implanted into the young woman’s 56-year-old mother.

My class took quite an interest in the many and varied reproductive possibilities raised by modern IVF techniques. They understood the obvious benefit, which is to enable some infertile couples to have children of their own. They also quickly grasped that it could also be used (in combination with preimplantation genetic diagnosis) to choose a child’s sex, to avoid having a child with certain genetic disorders, or even to cure an older sibling of a genetic disorder (See the Current Issue in Human Biology 5th ed., pp. 396-397). But they didn’t come up with this scenario!

Whatever Happened to Golden Rice?

Golden rice was once heralded as a cure for vitamin A deficiency, which kills or blinds children in poorer countries worldwide. But twelve years after its development golden rice is still not being produced and distributed. The primary reason is categorical opposition to all genetically engineered (GE) foods by organizations such as Greenpeace. Greenpeace argues that although golden rice might indeed benefit vitamin-deficient children, acceptance of golden rice would open the door to other GE crops that Greenpeace vehemently opposes.

In the face of intense, well-organized opposition, government regulatory agencies have been reluctant to approve GE crops, including golden rice. The company holding the patent on golden rice eventually gave up, saying there was no money in it. It's still being studied in a few labs by humanitarian organizations such as World Food Day, but don’t expect to see it on grocery shelves any time soon. That's too bad, for golden rice really is a product that could help people in need, as opposed to just helping food producers and manufacturers.