The Dark Side of Gender Preference

In China, 120 boys are born for every 100 girls. Experts think that the recent trend (since 1980) is the result of China’s “one-child” population-control policy, combined with a traditional society in which the eldest boy inherits the family land and is responsible for taking care of aging parents. So if a couple is planning on having just one child, usually they will decide it should be a boy. The boy/girl sex ratio is highest in rural areas; in cities, the earning power of women tends to be accompanied by a more normal sex ratio.

What can be done about it? One approach is educational programs to encourage couples to value daughters equally with sons; another is to allow families whose first child is a girl to have a second child; still another is to encourage young couples to live with her parents rather than his. The government is even offering cash payments for girls in some regions.

PRP Therapy for Connective Tissue Injuries

If you’ve ever injured a tendon or ligament you know how painful such injuries can be. You also know that injured connective tissue takes longer to heal than injured muscle tissue. That’s because there is generally very little blood flow to connective tissue, especially in areas in and around fluid-filled joints. As a result, very few blood platelets and white blood cells are delivered to the area to help with tissue repair.

Experts in sports medicine now think they have a potential solution. It’s called “platelet-rich plasma therapy”, or PRP for short. The method is surprisingly straightforward. A sample of the patient’s own blood is enriched in platelets by removal of the blood cells and most of the water and electrolytes. The remaining platelet-enriched plasma is then injected directly into the injured joint or connective tissue. The theory is that the platelets will release proteins involved in tissue repair and attract other tissue-repair cells to the area, speeding the healing process.

Does PRP therapy work for such common connective tissue injuries as rotator cuff strains, Achilles tendon injuries, and tennis elbow? Clinical trials are underway in several countries, including the U.S., to find out. Meanwhile, some professional athletes have already tried it, including Los Angeles Dodgers’ baseball pitcher Takashi Saito and Pittsburgh Steelers’ receiver Hines Ward. Ward has his answer already; he was able to play in the Superbowl just two weeks after a knee injury that generally sidelines players for 4-6 weeks.

Using Urine to Diagnose Disease

Your body gets rid of over a thousand different small metabolic waste molecules, called metabolites, by excreting them in the urine. In certain diseases one or more of these metabolites may be elevated in urine. Scientists now believe that through “metabolomics” – the study of metabolites – it may be possible to diagnose certain diseases even before symptoms appear in the patient.

The concept is simple; once you know the normal range of excretion of metabolites in urine, a change in the excretion of one or more metabolites might signal the presence of a specific disease. For example, scientists at the University of Michigan measured 1,126 metabolites in urine and found that one of them in particular, called sarcosine, showed promise as a marker for metastatic prostate cancer. The findings were reported in Nature this month.

Unlike blood, urine is easily collected in large quantities by non-invasive techniques. (Put more bluntly, you just pee into a cup!) As the field of metabolomics comes of age, perhaps some day it will be possible to screen for dozens of diseases at once.

FDA Approves a Genetically Engineered Drug

The first human drug produced by livestock genetically engineered to contain a human gene has now been approved by the Food and Drug Administration. A company called GTC Biotherapeutics developed a herd of goats (Figure 20.10 of Human Biology) that contain the human gene for antithrombin III, a protein used to prevent blood clots in people with hereditary antithrombin deficiency. One advantage of using farm animals is that larger quantities of human proteins can be obtained from the milk of genetically engineered animals than from human blood. One of GTC’s goats, for example, can produce as much antithrombin/year as the amount that can be extracted from 10,000 gallons of human blood!

How did GTC manage to get the antithrombin to be produced in milk, so they could harvest the protein by milking the goats instead of bleeding them? Simple concept, really - they linked the human gene for antithrombin to a goat gene for a milk protein.

8 Babies - How Did It Happen?

Last week a 33-year-old unwed California women gave birth to octuplets. Experts say that there are only two plausible explanations; they could have been conceived naturally if the woman had taken heavy-duty fertility drugs and had ovulated eight eggs at once, or an IVF clinic deliberately implanted eight embryos, against all current IVF treatment guidelines.

The woman’s mother has said that the woman had frozen embryos left over from previous IVF cycles, and that she had embryos implanted last year. But who would implant eight embryos?! It’s no surprise that the woman’s doctor has not yet come forward to take “credit” for this feat. Ethicists and fertility specialists are in agreement that implanting eight embryos during one IVF cycle would be unethical and irresponsible. Doctors apparently offered the woman the opportunity to reduce the number of embryos early in the pregnancy, but she refused.

This one is likely to be debated for awhile by ethicists and fertility experts. It might even be discussed on Oprah's show some day soon, if the woman can get enough money to appear! Reports are that she is holding out for several million dollars. Good luck.

Note added April 20, 2009: Apparently six embryos were implanted, but two split into twins. The maximum number of embryos which should be implanted is two, according to voluntary guidelines established by the American Society for Reproductive Medicine.

Scientific Uncertainty and Shared Responsibility

Here’s an interesting dilemma for you: An industrial chemical is known to cause a particular type of cancer in rats. A lifelong employee at the plant that makes the chemical is diagnosed with the cancer, so he sues the company for millions of dollars. Ultimately the employee loses the case and receives nothing, because the company’s lawyers argue (correctly) that the worker could have gotten the cancer from some other source, or that the worker had a genetic predisposition to cancer. In other words, the worker cannot prove scientifically beyond a reasonable doubt that his cancer was caused by exposure to the chemical while working in the company’s plant. Having won the case, the company continues to expose its current workers to the chemical.

Do we consider this to be fair, equitable, and just? Should the entire burden of uncertain science be borne by just one side?

Some lawyers are now arguing for the concept of “shared responsibility” when the scientific evidence leaves room for uncertainty. Perhaps the company should be asked to pay at least a small amount to its workers who develop the cancer as acknowledgment that their chemical might have caused the workers' cancers - not enough for the workers to have “won the lottery” or to bankrupt the company, but at least enough to help defray the workers’ medical expenses. Over time that might cause the company to reconsider continuing to expose its current workers.

What do you think?