Infertility Patients Favor Stem Cell Research

Most couples that have had to resort to in vitro fertilization (IVF) techniques in order to have a child are in favor of stem cell research. When asked in a national survey what they might choose to do with their frozen embryos left over after they have successfully had a child, 60% reported that they were “somewhat likely” or “very likely” to donate them for stem cell research. In contrast, less than a quarter of the respondents planned to discard their frozen embryos, or expressed a desire to donate them to another couple.

Infertility patients are especially aware of the advances in science that have made it possible for them to have children. Perhaps they are just more grateful than most, but apparently most of them have resolved any internal moral dilemma over what to do with their leftover embryos. It is interesting, however, that most of them would rather donate their embryos to research than to know that their biological child was being raised by another couple.

Phosphate Recovery From Sewage

In this blog (see "Dwindling Phosphorus Supplies") I talked about the world’s dwindling phosphate supplies, and how the key to sustainability of phosphate supplies would be recycling. But who among us has even thought about how we might recycle the gram and a half of precious phosphate we excrete in urine every day?

Well, a researcher at the University of British Columbia did, and then he set out to do something about it. Today, a phosphate recovery system based on his design is producing about a ton of slow-release phosphate fertilizer every day from a sewage treatment facility serving Portland, Oregon. The fertilizer is in such high demand that the recovery system will pay for itself in less than five years. Other recovery plants are planned, including larger ones to recover the waste from dairy and pig farms.

So if you live in Portland, Oregon, count yourself lucky; you already ARE recycling your phosphate! (Or at least somebody is.)

Reference: Tweed, Katherine. Sewage’s Cash Crop. Scientific American Nov. 2009, p. 28.

Tasting the Bubbles

It used to be assumed that the tingling sensation of carbonated beverages was due to stimulation of mechanoreceptors by bursting bubbles of CO2. In fact, researchers now know that we also have chemoreceptors for CO2, and that they are located on the same taste cells that detect sour taste. The receptor molecule is the enzyme carbonic anhydrase, which converts CO2 (plus a water molecule) into bicarbonate and a proton. Protons activate the taste cell, which in turn activates the sensory neuron that synapses with it.

Why don’t carbonated beverages taste sour, given that the carbonic anhydrase is located on the sour-detecting taste cells? No one knows for sure, but researchers speculate that the brain interprets CO2 receptor activation plus mechanoreceptor stimulation as primarily a tingling sensation.

Stem Cell Therapy for Parkinson's?

Researchers in Europe are about to begin a long and expensive series of experiments to determine if transplantation of fetal brain cells into the brains of patients with Parkinson’s disease will improve the patients’ condition. The study is raising some eyebrows in scientific quarters. Two similar experiments carried out in the U.S. in the 1990s, admittedly when the techniques were less well developed, failed miserably.

If they get final approval to go ahead, the researchers will harvest fetal brain cells from 6-9-week-old human fetuses and then inject the cells into the brains of patients with Parkinson’s disease. Up to six fetuses will be needed to obtain the 8 million cells to be transplanted into each Parkinson’s patient, according to a news article in Science. The first patients will receive the injections in 2012 as part of a safety study. If all goes well, a double-blind trial complete with sham surgeries will be carried out to see if the procedure actually benefits patients.

Controversial? Yes. Worthwhile? You decide.

Oldest Known Human Ancestor

In the October 2, 2009 issue of Science, scientists report on the discovery and reconstruction of the oldest known nearly complete skeleton of a female pre-human ancestor. Named Ardipithecus ramidus, “Ardi” stood only four feet tall and weighed about 110 pounds. Apparently she was a “facultative” biped, meaning that she could walk upright on the ground but was still able to climb and walk in trees.

The first bones of Ardipithecus ramidus were discovered in 1992, but it has taken this long to find and reconstruct enough of a skeleton to be confident enough to publish the results. And the results are stunning. At 4.4 million years old, Ardi pushes back the dawn of bipedalism by more than a million years. (“Lucy”, the celebrated Australopithecus afarensis shown on p. 518 of Human Biology, 5^th ed., is 3.2 million years old).

It’s the biggest find in decades. You can find 11 scientific articles on Ardipithecus ramidus in Science online. For a summary, read the Perspectives article by Ann Gibbons entitled “A new kind of ancestor: Ardipithecus unveiled”.

Encouraging Organ Donations

Fewer than 40% of all adults have signed a donor card or other legal document indicating their willingness to donate their organs after death. Perhaps it’s a form of avoidance, but for whatever reason we just don’t seem to get around to it. "Presumed consent" laws are one solution, but some people find presumed consent laws objectionable on the grounds that they are a form of religious discrimination. Under presumed consent, it's people who do not wish to donate (perhaps for religious reasons) who must make their wishes known in advance, not the other way around.

One innovative and eminently fair solution is to require everyone to make their wishes known. Its called “mandated choice”. In the State of Illinois, every person over the age of 18 who renews a driver’s license must answer the question, “Do you wish to be an organ donor?” The state now has a donor signup rate of 60%. Several other states (Pennsylvania, for one) ask the question as well, but it's for informational purposes only. In Illinois, the answer is considered legally binding, meaning that relatives cannot later overturn it.