Friday, January 23, 2009

Gender Bias in Kidney Transplants

According to a report that will be published shortly in the Journal of the American Society of Nephrology, women over the age of 45 who need a kidney transplant are less likely to get one than men of the same age. This despite the fact that they are no less sick than the men and would benefit just as much as the men by having a kidney transplant.

So why the bias against older women? The researchers aren’t sure, but they speculate that women may be seen as more frail than they actually are by whoever makes the decision to put (or not to put) a female patient on the deceased-donor waiting list or to help them find a live donor. Or, perhaps the women themselves think they are less likely to survive the surgery or benefit from the transplant.

In fact, the researchers found no difference in the survival benefits between men and women, and even between older men and older women. We may need to look carefully at why older women are not getting the transplants they need.

Thursday, January 22, 2009

Antibiotic-Resistant Bacteria

Researchers have recently uncovered more evidence of an increased trend toward antibiotic resistance by Staphylococcus aureus infections, this time in infections in children. As you may know, staph is a nasty little bacterium that can lead to severe skin lesions. According to the report, the percentage of staph infections that were resistant to methycillin, the antibiotic most commonly used against staph, rose from 11.8% in 2001 to 28.1% in 2006.

Health workers worry that someday our current antibiotics just won’t be very effective any more. For more on this topic, see (See “The Growing Threat of Antibiotic-Resistant Bacteria” in Human Biology 5th ed., p. 18).

REFERENCE: Naseri, I., et. al. Nationwide Trends in Pediatric Staphylococcus aureus Head and Neck Infections. Archives of Otolaryngology - Head and Neck Surgery 135:14-16, 2009.

Sunday, January 18, 2009

Young Adults Turn to Sleeping Pills

Prescriptions for sleep medications increased nearly 50% in adults under the age of 45 between 1998 and 2006, according to a report in The New York Times. Among young adults aged 18-24, the use of heavily-advertised prescription sleep medications such as Ambien CR and Lunesta nearly tripled. These drugs truly are safer than older, benzodiazepine-based products, so there would seem to be little reason not to use them to get a good night's sleep.

However, in some cases these drugs may be prescribed too readily. Many of these prescriptions are written when the patient is being seen for something other than a sleep disorder, such as a general medical examination or a menstrual disorder. The worry is not the safety of the drugs per se, but that patients may not be receiving much-needed medical workups to eliminate potential underlying psychiatric disorders before prescriptions are written.

If all you want is a good night's sleep, what about adjusting your behavior or environment a little? You might just get a good night's rest if you were to move out of that noisy dorm and stop drinking 6 cups of coffee a day! Just a thought.

Saturday, January 17, 2009

An Impact of Humans on Evolution

Evolutionary processes may be impacted by human activities, such as trophy hunting for big-game animals. Some of the evidence comes from a study of bighorn sheep published about 10 years ago. The article documents a substantial decline in body size, horn size, and reproductive success among four-year-old (young breeding age) male bighorn sheep in one location in Alberta, Canada over 30 years as the result of the hunting practices that targeted primarily the prime breeding-age males.

Is there a solution to this problem that would still allow trophy hunting? Well, yes there is, and it lies in a key concept of evolution - that the death of an individual animal after his/her reproductive years cannot affect heritable processes. Therefore, hunters should be allowed to harvest only the truly old males; males so old that they are unlikely to be competing successfully with younger, more fit males for females. In bighorn sheep this age is probably about 8 years, when the horns generally form a complete curl. Wildlife management experts are taking heed. Over the years the legal minimum horn length for bighorn sheep has risen in most wildlife management areas from 3/4 curl, to 4/5 curl, and now to full curl. The number of male bighorn sheep harvested each year dropped for awhile, but that’s the price that has to be paid. Sound wildlife management practices based on good science will benefit us all, whether or not you hunt.

Incidentally, a more widespread problem may be commercial fishing. When minimum size limits are set, the surviving female fish are smaller, reproduce at a younger age, and produce fewer eggs. In other words, when humans harvest the big fish, the puny fish are more likely to survive to pass on their genes.

Thursday, January 8, 2009

Focus on Evolution

The January, 2009 issue of Scientific American is focused almost entirely on the subject of evolution. There are articles about Darwin, testing Darwin’s concept of natural selection, the molecular basis of species variation, human evolution, and how creationists misrepresent evolution in an effort to have religious ideas taught in school. In short, it’s a good source for additional reading material for your class on virtually any topic on evolution you might wish to emphasize.

Monday, January 5, 2009

Storing Umbilical Cord Blood

An article entitled “When Medicine Meets Marketing" (Newsweek Dec. 22, 2008, pp. 49-51) would be a good supplementary reading for when you cover the topic of blood in your human biology college course. The article describes how private blood storage companies are waging a fierce marketing campaign designed to convince young parents to bank their baby’s cord blood (for a hefty fee), just in case the stem cells in cord blood might be useful in the future. The scientific background for understanding the article is covered in Human Biology.

Based on what you have learned from the textbook and/or from the Newsweek article, are you more likely to; a) bank your baby's cord blood privately, b) donate your baby's cord blood to a public cord blood bank registry, or c) do neither? On what do you base your choice?