Sunday, December 28, 2008
According to a pair of articles published about 10 years ago, maintaining your usual exercise regimen may be good for you when you have a cold, or at least it will do no harm. A typical head cold with a runny nose and sneezing does not affect lung function or exercise capacity. And although exercise doesn’t actually speed recovery time, people who continue to exercise during a head cold tend to report that they feel better than people who don't exercise. So the next time you catch a cold, go ahead and continue doing whatever exercise you enjoy doing.
"Effect of rhinovirus-caused upper respiratory illness on pulmonary function test and exercise responses". Weidner TG et al. Med. Sci. Sports Exerc. 29:604-609, 1997.
"The effect of exercise training on the severity and duration of a viral upper respiratory illness". Weidner TG et al. Med. Sci. Sports Exerc. 30:1578-1583, 1998.
Friday, December 19, 2008
A technique just now being developed would make testing for the presence of abnormal plasma proteins easy, quick and cheap. The technique is based on glass and plastic microfluidic chips that can test for dozens of proteins in a single drop of blood, in just minutes, for pennies per test. The new technique is described in the Dec. 19 issue of Science.
Thursday, December 18, 2008
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.
Wednesday, December 17, 2008
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?
Tuesday, December 9, 2008
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).
Monday, November 24, 2008
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?!
Thursday, November 20, 2008
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.
Thursday, November 13, 2008
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!
Tuesday, November 11, 2008
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.
Sunday, November 2, 2008
Once consumers understand what the logo means and accept its underlying health assumptions, they can simply look for the logo on the front of the package. “Pattern recognizers” such as myself (who can’t find their favorite products in the grocery store if the manufacturer changes the packaging!) will appreciate the help in picking healthful foods. The logo is a green check mark in a square along with the words, “Smart Choices Program”. For a complete listing of the nutritional requirements to earn the Smart Choices label, visit the Smart Choices website. The logo should begin appearing on products in stores by the middle of next year.
Friday, October 24, 2008
Well, it seems that the new-species proponents are gaining ground these days. Analysis of LB1’s hands and feet suggest that this is not the skeleton of a modern but diseased human. Her wrist bones and especially her feet are closer to those of Homo erectus, an African Hominid that lived in Africa more than a million years ago. Her feet are so long that scientists think she must have walked with a high-stepping gait and been a poor runner. How Homo floresiensis reached Indonesia and survived there for over 50,000 years is a mystery.
For a good look at the one skeleton unearthed so far, see “When Hobbits (Slowly) Walked the Earth”, Science April 25, 2008, pp. 433-435. You can get the article online at www.sciencemag.org - search for "When Hobbits".
Wednesday, October 15, 2008
Sales of these products continue to climb. Health officials are growing increasingly concerned by reports of acute caffeine intoxication, dependence, and withdrawal among children. There is also a trend toward the combined use of energy drinks and alcohol among young adults.
Which ones do your students drink? Do they know what’s in them?
Tuesday, October 14, 2008
The European Commission is planning a conference for early 2009 to discuss the committee’s findings with industry, consumers, and governments, and to consider whether there is a need for tighter controls over portable music players. I would not be surprised to see new legislation emerge that limits the maximum sound volumes attainable with portable music players.
SCENICOR’s 80-page preliminary report, released in June for public comment, is available online.
Monday, October 13, 2008
Researchers caution that so far, the research has only been done on mice. Still, it’s encouraging to see herbal remedies being subjected to the same kind of careful scientific scrutiny that has traditionally been applied to therapeutic drugs. This is exactly what we had hoped for, as discussed in Human Biology 5th ed. in the Current Issue essay entitled “Antioxidants: Hope or Hype?” (pp. 42-43). In time perhaps we’ll know the real story behind herbal remedies, and not have to rely on anecdotes and hype.
Thursday, October 9, 2008
According to World Anti-Doping Agency rules, an athlete’s blood may be retested for up to eight years after an athletic event. The International Olympics Committee keeps blood samples for eight years for situations like this, in which a new test is developed to detect a previously undetectable performance-enhancing drug. It’s just another way that sports authorities try to keep up with athletes who are willing to cheat. Sports authorities hope that the knowledge that an athlete might still be stripped of his/her medals up to eight years after a competition will deter some athletes from using drugs in the first place. But the desire to win is strong, and no one knows if the strategy will work.
Wednesday, October 8, 2008
Instructors will be interested in the detailed report by the Intergovernmental Panel on Climate Change (IPCC) entitled “Carbon Dioxide Capture and Storage – Summary for Policymakers”. The article has some great illustrations that would be useful in teaching. They can be used free with acknowledgment.
Saturday, September 27, 2008
Wednesday, September 24, 2008
A promising new screening test for ovarian cancer called OvaSure can correctly identify ovarian cancer 95% of the time. Ovarian cancer is one of the most deadly cancers if it is not detected early. The company marketing the test says that the test has a false-positive rate of only 0.6%. (A false-positive is when the test indicates that cancer is present when in fact it is not.) Should the test be made widely available as a screening test for ovarian cancer?
Let’s see; 95% success rate at detecting ovarian cancer versus a 0.6% false-positive rate – it doesn’t sound like much of a dilemma, does it? But it is an interesting dilemma, and the reason is that ovarian cancer is rare; its prevalence is only about 0.06%. So among 100,000 women screened with the new test, 60 (0.06% of 100,000) would have ovarian cancer and 57 of them (95%) would be diagnosed correctly. Many of these 57 might be saved. However, 600 women (0.6%) would be told they had ovarian cancer when they did not. In the absence of any good corroborating tests to confirm the diagnosis, many of those 600 women might choose to have a surgery they actually didn’t need. And almost certainly they'd suffer emotionally from the belief that they had a deadly cancer.
Sometimes you have to run the numbers carefully to see the full effect of what is being said. It pays to be a skeptic.
ADDENDUM: Ovasure was pulled from the market in October, 2008, after the FDA sent the company a letter saying that the kits required FDA approval before they could be marketed and sold.
Saturday, September 20, 2008
Well, if those odds still aren’t good enough, now gender can be selected with essentially 100% accuracy. Basically, it’s a variation of the standard in vitro fertilization (IVF) technique: 1) harvest eggs from a woman according to the standard IVF protocol, 2) fertilize the eggs in vitro, 3) grow the embryos to the 8-16 cell stage, 4) Remove a cell for DNA analysis to determine the presence or absence of the Y chromosome, 5) implant only embryos of the desired sex. Bingo, it’s a girl! (Or a boy).
Removing a cell for DNA analysis doesn’t affect the ultimate development of the fetus because at that stage none of the cells have begun to differentiate. In fact IVF with DNA analysis is already being done to screen out certain rare but debilitating genetic diseases, where the risk of these diseases is considered high. But before a couple chooses to use it to select gender, they should consider that it’s expensive, it’s invasive, and some would say it goes against nature.
Where do your students stand on this? Are they aware that there are clinics advertising on the Internet that are routinely doing it? (Google “IVF” and “gender selection”).
Friday, September 12, 2008
Until now the market for irradiated foods has remained small because current FDA regulations require that irradiated foods be labelled as “irradiated” and display an irradiation logo. The labels have convinced some consumers that irradiated foods may be radioactive (they’re not). To encourage consumer acceptance, the FDA has proposed changes to the labelling rules so that in the future, irradiated foods would only have to be labelled as “cold pasteurized”, or simply pasteurized.
How accurate are your student’s perceptions about food irradiation? How many of them mistakenly believe that irradiated foods are radioactive? The safety of food irradiation might make a good out-of-class research project or topic for discussion.
Tuesday, September 9, 2008
Over the same time period (1981-2006), the sea surface temperatures have risen by 0.5 degrees Fahrenheit. Most climatologists believe that warmer waters are certain to lead to stronger storms, because hurricanes derive their energy from the heat of warm surface waters.
Friday, September 5, 2008
Here’s an interesting exercise you could give your students: Ask them to search a key phrase such as “bird flu”, “avian influenza” or “H5N1” in any major newspaper with a searchable archive (such as the New York Times), arrange the retrieved documents by date, and count them. I searched “avian flu” in the New York Times recently and found that references peaked at 181 in 2006 and have since fallen to a paltry 18 in the first eight months of 2008.
Psychologists surely would have something to say about how long we can sustain our fear of a perceived threat that doesn’t materialize quickly. Health officials worry that if we become convinced that bird flu is not a threat any more, we will begin to make political and economic choices that direct our resources away from preparedness programs. And no one knows whether or not that would be a good idea at this point.
What do you think?
Monday, September 1, 2008
See “The Specter of Malthus Returns”. Scientific American September 2008, p. 38. Your students could read and appreciate Dr. Sachs’ one-page opinion piece on the subject. In my class the article led to a spirited discussion of the wide disparities in resource utilization by different countries.
Monday, August 25, 2008
Measles is highly contagious, so it is no surprise that it may be among the first vaccine-preventable diseases to reappear when vaccination rates decline. Fortunately, measles is not very virulent; most patients are treated at home and recover without any long-term consequences. But if the return of measles is an early indication of lower vaccination rates, it may only be a matter of time before other vaccine-preventable diseases return as well. And that has health officials worried.
How do you feel about childhood vaccinations?
Sunday, August 24, 2008
It would be interesting to know whether humans also give off alarm pheromones. Could this be an explanation for why people seem to internalize the stress of others around them?
Thursday, August 21, 2008
A study published last December tends to support the hypothesis that being overweight is not as important a factor previously thought (Journal of the American Medical Association 298:2507-2516, December 5, 2007). In this study, 2603 adults over the age of 60 were tested for cardiovascular fitness (gentle treadmill test) and then mortality was followed for 12 years. Overweight individuals did have a higher mortality rate than did normal-weight individuals (18 vs 13 deaths per 1000 person-years). However, even more striking was the effect of fitness; mortality rate of the least-fit quintile was four times that of the most fit quintile (33 vs. 8 deaths per 1000 person-years.) Among the older generation at least, maintaining cardiorespiratory fitness may be more important than maintaining a normal body weight. Whether this is also true for younger individuals remains to be seen.
Wednesday, August 13, 2008
Law enforcement officials and crime investigators will welcome the technique as another weapon in their arsenal against crime. But the ability to test fingerprints for certain chemicals could also raise some privacy concerns for us all. Would we consider it ethical for an employer to enter workers’ offices to check for fingerprints containing traces of illegal drugs, without the employee’s knowledge or consent?
Reference: “Latent Fingerprint Chemical Imaging by Mass Spectrometry”. Science 321:805, August 8, 2008.
Sunday, August 10, 2008
Well, yes…..maybe. A document released this month by the AIDS Vaccine Advocacy Coalition describes a potentially powerful new HIV prevention method called pre-exposure prophylaxis (PrEP.) It’s a simple notion, really – that a daily pill consisting of one or more of the current AIDS treatment drugs might prevent HIV infection from occurring in the first place. There are at least seven clinical trials of PrEP either planned or underway using the drugs tenofovir and emtricitabine, both of which are already approved for treating people who are currently HIV-positive.
No one knows for sure whether PrEP will work, but there are some promising signs that it might. But even if PrEP does prevent HIV infection, there would still be the issues of access and cost. In order to prevent HIV infection the drug would need to be available to a lot of healthy people, rather than just the few who are already infected.
A report on the status of PrEP research and some of the issues related to its use in AIDS prevention can be accessed at www.avac.org/prep08.pdf.
Wednesday, August 6, 2008
How could the numbers have been so far off? For one, the new data are based on better testing methods that more precisely differentiate new HIV infections from long-standing ones. In addition, HIV infection rates are notoriously hard to come by, especially back in time. Even the new estimates are based on extrapolations using data from only 22 states. The CDC does the best it can do with limited data; the rest is an educated estimate.
Officials emphasize that this does not mean that there actually were more new cases of HIV – rather, we now have better estimates of the actual rates of new infection that existed at the time, regardless of whether or not they were accounted for. Nevertheless, some Democrats are criticizing the Bush administration for not doing enough to combat HIV/aids in this country. Senator Waxman of California released a statement last week in which he pointed out that the CDC budget for prevention has actually shrunk by 19% since 2002, and that the president recently requested a reduction in funding for HIV prevention at the CDC. Given that the incidence of HIV has not declined at all over the past 15 years, Senator Waxman may have a valid concern.
Students may react with a "So what are we supposed to believe, when even scientists can't get it right?" attitude. They'll need convincing that this kind of "flip-flop", as it would derisively be labeled in politics, is actually a normal part of a healthy scientific process.
Monday, August 4, 2008
The commercial possibilities and health implications are almost limitless. If food product manufacturers could use less sugar in their products and still satisfy our craving for that sweet taste, perhaps people would be able to diet more effectively. Caloric intake might decline, leading to a reversal of the obesity epidemic. Less salt in our food products might mean less cardiovascular disease. Block the bitter taste receptors and children would eat more vegetables. Bitter medicines would be more palatable, improving patient compliance in taking them.
Some big companies are interested, including Coca Cola, Nestle, and Cadbury. Nestle is already using a flavor modulator from Senomyx in some of its products. Read about it in this month's Scientific American (“Magnifying Taste.” Scientific American August, 2008, pp. 96-99.) You’re likely to see “flavor modulators” or “taste enhancers” listed among your favorite products’ ingredients in the near future.
Saturday, August 2, 2008
Trans fats are created by bubbling hydrogen through liquid oil at high temperature. The resultant partially hydrogenated oil is a solid at room temperature. Trans fats prolong the shelf life and (some say) improve the flavor of foods. They were popular as a deep-frying oil until it became apparent that they raise the levels of low-density lipoproteins (the bad cholesterol), thereby potentially contributing to heart disease. Some restaurant chains, most notably McDonalds, have already discontinued the use of trans fats in their deep-fryers, and other chains are following suit.
The California ban raises an interesting question: Whose responsibility is it to legislate our health? The California Restaurant Association argued (unsuccessfully) that it should be the federal government, not the states – otherwise, restaurants with outlets in many states could face a wide array of different rules.
But if the government won’t act, should the states be allowed to? Until California’s law is challenged in federal courts, the answer is “Yes”. What do YOU think?
Sunday, July 27, 2008
What do you think? Read Mr. Shermer’s one-page opinion column in the August issue of Scientific American (“Wheatgrass Juice and Folk Medicine”, Scientific American August 2008, p. 42) and judge for yourself. This article might be a useful supplement for Chapter 1, Human Biology, 5th ed.
Tuesday, July 22, 2008
This would be a good article to share with your students in support of the Health Watch box on page 18 of Human Biology, 5th ed. The article could also be used to kick off a class discussion of the economics of developing and selling pharmaceutical drugs.
Sunday, July 20, 2008
There may be good news for Gaucher’s disease sufferers soon. An Israeli company named Protalix Biotherapeutics has developed a protocol for producing recombinant glucocerebrosidase cheaply in large amounts. But they’re not using animals – they’re using genetically engineered carrot cells grown in cell culture in big plastic bags. The enzyme is already in Phase III clinical trials, meaning that it is being tested in human patients. If approved by the FDA it will be the first plant-made recombinant drug ever approved for use in human patients. This could be a breakthrough that leads to a whole new field in drug development – making drugs by inserting human genes into plant cells.
To read more about it and see a photo of the carrot cells in culture, go to Protalix’s website at www.protalix.com.
Thursday, July 17, 2008
The study’s authors most likely were disappointed (the study was funded in part by the Atkins Foundation, and a low-carb diet was one of the diets tested.) But based on some observed changes in lipid profiles, they suggest that the diets may have conferred some health benefits to the participants despite the minimal weight loss. It’s an interesting hypothesis, but it’s certainly not a valid conclusion at this point.
Reference: “Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet”, The New England Journal of Medicine 359:229-241, July 17, 2008.
Tuesday, July 15, 2008
The techniques for tracing human migrations and the various routes taken are documented in “Traces of a Distant Past” (Scientific American, July 2008, pp. 56-63.) This would be a great paper to share with your students when you're discussing human evolution.
Sunday, July 13, 2008
Four days later, FOX news went one step further with a story entitled “HPV Vaccine Blamed for Teen’s Paralysis” (foxnews.com, July 11).
This is biased journalism at its worst. Who exactly is blaming Gardasil for Jenny’s disease - Fox News? In fact the Fox News article is full of errors. For one, the article attributes to Jenny’s parents a statement made by a spokesperson for Merck, Gardasil’s manufacturer. In addition, the article uses the word “casually” in place of “causally”. For the record, what a Merck spokesperson actually said was, “We’re aware of this case and based on the facts that we’ve received, the information doesn’t suggest that this event was causally associated with vaccination.”
On their blog site on July 7 (see www.jenjensfamily.blogspot.com), the parents expressed disappointment with the CBS news coverage, saying “The family believes that there may be a link between Jenny’s health and the HPV vaccination……” “But, there is no medical consensus on whether this hypothesis is stronger than other possible explanations.”
Jenny’s parents are obviously scientifically literate. They know how to distinguish between a hypothesis and a scientifically justifiable conclusion. As you’re discussing the importance of being scientifically literate in your classroom, Jenny’s parents’ blog site and the two news articles would make interesting topics for discussion.
One final thought: Do you think that the biased news coverage of Gardasil could be intentional, given that conservatives don’t like the idea of a vaccine against a sexually transmitted disease being given to young girls? What do your students think?
Sunday, July 6, 2008
Are you concerned? How much radiation does your cell phone emit, anyway – a lot, or a little? The Federal Trade Commission sets an upper limit of 1.6 W/kg (watts per kilogram) for certification, but commercial phones on the market vary all the way from 1.6 down to 0.14 – more than a 10-fold difference.
For a complete listing of the radiation output of all current phone models, go to http://reviews.cnet.com, go to “Reviews - cell phones”, then click on “Cell phone radiation charts.”
Friday, June 27, 2008
This is a good example of the limitations of the scientific method, and why it is sometimes hard to know the truth. Regarding the first statement, yes, cell phones may cause brain cancer (and then again, they may not.) As for the second statement, it is true that there is still no scientifically convincing evidence that cell phones are a health risk. (But again, that doesn’t mean they aren’t!)
Why is it so hard to find the truth? First, brain cancers are so rare that one would have to study literally hundreds of thousands of people. Second, to do the scientific study properly, a controlled study would need to be done in which the lives of hundreds of thousands of people would have to be strictly controlled. It can’t be done. Third, no one has used cell phones for 50 years, so potential long-term effects won’t show up for awhile. And fourth, modern phones emit much less energy than the older models did.
What can we do? We can study those few patients with brain cancer and ask questions – questions about health habits, including past cell phone use. Self-reports by patients are notoriously unreliable, of course, so it may take hundreds of such studies before we consider the evidence “convincing”. We don’t need to panic, but we need to be watchful of the changing state of knowledge regarding cell phones and cancer.
Incidentally, a similar question came up in the 1950s when smoking was actively encouraged – does smoking cause lung cancer? Who could have known that nearly sixty years later the rates of lung cancer in persons over 65 would be more than five times the rates of that same age group in 1950?! However, this does not imply in any way that the same sort of outcome is inevitable for cell phones. They're totally different issues.
Sunday, June 8, 2008
See the brief news article on this subject in Science magazine (“Bacteria are Picky About Their Homes on Human Skin”, Science May 23, 2008, p. 1001.)
Saturday, June 7, 2008
Traditionally, biologists loosely define a species as a population whose members breed mostly among themselves under natural conditions. Generally this means that they are genetically distinct. But now that we can sequence DNA, the concept of “genetically distinct” itself is problematic - exactly how many genes or base pairs have to be different? As one species evolves to become two, when are they different enough? It’s not just a philosophical exercise; how a particular species (or group of individuals within a species) is defined may determine whether it is an “endangered species” or not, and thus worthy of protection under the law. It can mean its very survival.
For a good recent article on the subject, see “What is a Species?”, Scientific American, June 2008, pp. 72-79.
Monday, June 2, 2008
GINA makes it illegal for health insurers to deny coverage or raise premiums based on genetic information. It also prohibits employers from using genetic information in making decisions regarding job assignments, promotion, hiring, or firing. Patients and health care workers had been pushing for the bill for years, claiming that people were afraid to take genetic tests, such as the one for the breast cancer genes BRCA1 and BRCA2, because they were afraid of being denied insurance coverage or a job should they test positive.
Why did it take so long for the bill to pass? Some lawmakers, most notably Senator Tom Coburn of Oklahoma, were worried that the bill would create a windfall for trial lawyers as people sued insurance companies and employers over alleged discrimination in health care coverage. The final bill addresses that question to everyone’s satisfaction, apparently.
Sunday, June 1, 2008
The energy drink Spike Shooter contains 428 mg of caffeine in 12 ounces, or about 12x that of Coke or Pepsi and 2-5 times that in a cup of coffee. Teens have been sent to the emergency room with heart palpitations, jittery behavior, and sweating as a result of drinking too many energy drinks. Some teens are combining these drinks with alcohol in the mistaken belief that it makes them less drunk.
Do your students use energy drinks, and do they know what's in them?
Wednesday, May 28, 2008
So it’s not just a rising average temperature that we have to worry about with global warming; shifting weather patterns are likely to be just as disruptive. See “Synthesis and Assessment Product 4.3 (SAP 4.3): The Effects of Climate Change on Agriculture, Land Resources, Water Resources, and Biodiversity in the United States”, at climatescience.gov.
Friday, May 23, 2008
The auction will be held July 5th through 9th online, with bidding to start at $100,000. The company promises the buyer a puppy that resembles the original dog, guaranteed healthy for a year. The company says that the success rate with cloning dogs has improved to the point that 25% of all embryo transfers now result in a puppy, and that the puppy survival rate is 80%.
Human cloning can’t be far behind. The sticking point is the success rate and the health of the clone – do we really think that a survival rate on the order of 80% would be worth the risk? No one knows the long-term health risks.
Monday, May 19, 2008
A similar plan was abandoned in the 1990s after a public campaign was mounted against it. But this time around the critics seem to be less vocal, in part because the chronic water shortage in LA is predicted to only get worse and in part because the technology for cleaning up sewage water keeps getting better and better.
It might be interesting to ask your students if they would vote for such a plan in their community, or ask them what THEY would see as the best way to solve a water shortage problem. You could also ask them to look into and report on current techniques for treating sewage water.
Saturday, May 10, 2008
But now, researchers have discovered that although you do have a constant number of fat cells throughout life, they are not the same cells. About 10% of them die each year and are replaced by new ones.
No one knows for sure what determines how many fat cells each person has. But the findings open up interesting new avenues for weight control research. If we could determine what regulates the number of fat cells and then alter that regulation, or if we could slow the rate of fat cell division, we might have a new way to fight obesity.
Monday, May 5, 2008
“Religious belief is not science,” said the state’s commissioner of Higher education in recommending to the board that they disallow the ICR application. He added, “Science and religious belief are surely reconcilable, but they are not the same thing.”
Wednesday, April 30, 2008
Two-thirds of the Asian population and about 10% of all Caucasians are deficient in the gene in question. The World Anti-Doping Agency is concerned, but it appears that there is little that they can do about it at this time. Genetic tests would reveal which athletes could beat the testosterone doping test, but genetic testing is not part of the standard anti-doping test for Olympic athletes. Individuals with the genetic deficiency may be able to use testosterone and get away with it, at least until the rules change.
Monday, April 28, 2008
If you wish to update the graph on p. 556 of Johnson's Human Biology, 5th ed., place a green dot at 385 ppmv for 2007 and then re-draw the green line from 2000 to 2007. The line is still curving upward, and getting steeper.
Wednesday, April 23, 2008
The Lyric or other products like it may well revolutionize how we correct deficits in hearing, similar to what disposable contact lenses did for eyeglass wearers.
Monday, April 7, 2008
None of the antibiotic-eating soil bacteria is a known human pathogen - at least not yet. But bacteria often swap genetic material by a process called conjugation; what if these bacteria were to pass their antibiotic-resistant genes to a truly nasty human pathogen? No one knows how likely this might be at this point.
Instructors will be interested in the original research article (“Bacteria Subsisting on Antibiotics”. Science 320:100-103, Apr. 4, 2008). Students could be given the editorial comment, page 33 of the same issue. Its worth discussing in conjunction with the Health Watch feature on antibiotic resistance in Chapter 1 of Human Biology, 5th ed.
Thursday, April 3, 2008
But is that how the RNA interference drugs currently under development actually work? New evidence just published online in Nature on March 26 (doi:10.1038/nature06783) suggests that the drugs may be working by a much more general mechanism – activation of the immune system. If so, the drugs may have side effects that have not yet been considered. The findings were such a surprise that the stock prices of small companies working on RNA interference drugs went down briefly.
The Nature article is for experts only. For students, I suggest the more general New York Times article published online on Apr. 2 (“Study is Setback for Some RNA-Based Drugs”, http://nytimes.com/2008/04/02/business/02place.html).
Tuesday, April 1, 2008
The new suit has no stitching; the parts are all bonded ultrasonically. Low-drag panels are incorporated into the nearly complete body suit to compress the swimmer’s body. According to the company, the new suits have 5% less drag than older models. Critics argue that a suit doesn’t make a world-class swimmer, and of course on one level they’re right. On the other hand, in the past two months 14 new world records have been set in swimming – 13 of them in the LZR suit.
Expect to see the new suit all over the Olympics swimming competitions this summer.
Sunday, March 30, 2008
We don’t mention Homo antecessor in Human Biology, 5th ed. so that the beginning student is not baffled by the number of pre-human hominid names that have cropped up in recent years. Until more fossils are discovered, it might be best to lump Homo antecessor with other better-known European archaic humans such as Homo heidelbergensis.
Reference: “The First Hominin of Europe”. Nature 452: 465-469, March 27, 2008.
Monday, March 17, 2008
Cerezyme is used to treat a rare inherited disorder called Gaucher disease, characterized by severe deterioration of bones and joints. The recommended dosage was determined on the basis of a clinical trial in only twelve patients more than 20 years ago. At the recommended dosage the drug has proven to be quite effective. But would a lower dose work just as well? Many doctors and insurance companies think so, but the manufacturer (Genzyme) has no interest in finding out. And why would they, when the drug has annual sales of over a billion dollars? Genzyme says it’s not their issue; they’d leave it up to doctors to determine whether a lesser dose would work just as well in their patients.
If the drug were cheap, dosage wouldn’t be an issue. But insurance companies are paying for this drug, and therefore so are we, indirectly. Who do you think should be responsible for determining the proper dose?
Thursday, March 13, 2008
Now we know that the DNA of identical twins is not always identical. That's because as cells divide over and over again during normal human growth and development, some sections of the DNA are omitted accidentally once in awhile. Other sections of the DNA are duplicated unnecessarily. The result is that some somatic cells and even tissues and whole organs may have one to three copies of some genes, instead of the usual two. Such copy number variations occur rarely in all people, not just in identical twins.
It would be helpful to know whether copy number variations contribute to specific human diseases, and (out of curiosity) whether copy number variations contribute to the slightly different phenotypes of some "identical" twins.
Monday, March 10, 2008
What happened? For decades, scientists and drug marketers dreamed of blockbuster profits from the first inhalable insulin product that would eliminate the need for injections in the treatment of diabetes. It turns out that no one cared. Patients didn’t like the cumbersome device used to administer the powdered insulin, and doctors found that the powders had a slight tendency to impair lung function.
It seemed like such a good idea.
Saturday, March 8, 2008
What about the women who were on HRT during the study - do they remain at higher risk even after discontinuing HRT? The good news is that apparently most of the increased risk goes away with time. The first follow-up study indicates that three years after HRT is discontinued, the increased risk of heart attacks disappears, and the increased risk of cancer declines significantly. Future reports will show whether any increased risk of cancer remains as time passes.
Current recommendations for HRT remain unchanged; women should consider HRT only if they have moderate to severe post-menopausal symptoms, and for the shortest time and lowest dose that is effective.
Monday, March 3, 2008
Why is that? The authors suggest that its because “Global warming is an extreme collective action dilemma, with the actions of one person having a negligible effect in the aggregate.” They suggest that because informed persons understand this, they tend to feel less personally responsible and more pessimistic about their ability as individuals to change the outcome.
Okay, informed persons may feel less responsible, but why are they less concerned? One possible explanation is that people who are informed about science tend to trust that scientists will find a technological solution. After all, we’ve sent men to the moon, discovered antibiotics, and developed computers, haven’t we?
How confident are your students that scientists will find technological solutions to global warming in their lifetimes? Do they see any technological solutions on the horizon?
Thursday, February 28, 2008
Monday, February 25, 2008
And yet, it appears that many people are avoiding DNA tests out of fear that the information could be misused. They worry that if their DNA test reveals a strong likelihood that they might develop a costly or life-threatening genetic disease later in life, they will become uninsurable even though they are currently healthy (see “Fear of Insurance Trouble Leads Many to Shun or Hide DNA Tests”. The New York Times, Feb. 24, 2008). Insurance companies deny it, of course. But even if insurance companies aren’t currently engaged in genetic discrimination, the commonly held perception that they could is enough to cause some people to avoid DNA tests.
Would your students take a DNA test to determine their risk of developing breast cancer or prostate cancer if those diseases ran in their family? You might ask them.
Wednesday, February 20, 2008
Tuesday, February 19, 2008
Reference: Nelson, J.Lee. Your Cells are My Cells. Scientific American Feb. 2008, pp. 72-79.
Sunday, February 10, 2008
Wednesday, January 30, 2008
The synthesis of the entire genome of an organism paves the way for experiments to determine the minimum number of genes required for life – the minimum operating system, so to speak. Looking further to the future, someday it may even be possible to create synthetic organisms for specific purposes, such as manufacturing medicines or cleaning up the environment. We’d better start thinking about how we want to regulate or control this new technology.
Monday, January 14, 2008
Saturday, January 12, 2008
Friday, January 11, 2008
Thursday, January 3, 2008
Interestingly, both sides are trying to justify their position on the basis of science. Those opposing the planting of the GM corn argue that one can never be absolutely certain that the new corn is completely safe. They are right, of course; science cannot absolutely prove GM corn’s safety under all known (and as yet unknown!) conditions. On the other hand, those in favor of planting the GM corn argue that according to the currently available scientific evidence, GM corn is “unlikely” to pose a significant risk. They are right, too.
Ultimately, the decision of whether or not to ban GM corn will be a public policy decision based not only on the available scientific data, but also on political, economic, and social pressures. Nevertheless, science certainly does have an important role in issues such as this. Points of concern raised during public debate can perhaps be tested by science, improving our confidence in public policy decisions both now and in the future.