Sunday, December 27, 2009
Almost immediately the new find created a controversy. If Homo floresiensis descended from the much larger Homo erectus, how did they come to be so small, and in particular, how did their brains become smaller, too? Some scientists postulated that the skeleton was just a diseased modern human; others argued that the new species had undergone a phenomenon known as “island dwarfing”.
Analysis of the morphological features of Homo floresiensis has led to a new theory, summarized recently by Kate Wong in Scientific American – that Homo floresiensis descended not from Homo erectus, but from older (and smaller) ancestors, such as Homo habilis. That would explain LB1’s small size and diminutive brain, but it raises more questions than it answers. For example, if Homo floresiensis diverged from other known human lines nearly two million years ago, why haven’t other skeletons of this species been found? Did Homo floresiensis emigrate from Africa even before Homo erectus did? Where did they go before arriving in Indonesia?
It’ll be interesting to see how our thinking about Homo floresiensis evolves as new information comes in.
Reference: Wong, Kate. Rethinking the Hobbits of Indonesia. Scientific American, Nov. 2009, pp. 66-73.
Monday, December 14, 2009
The French team has the approval of French authorities to treat more patients with the same inherited disorder. The hope is that someday they’ll be able to successfully treat one of the most common of all genetic blood disorders – sickle cell anemia.
Saturday, December 12, 2009
Deaths caused by the flu are notoriously hard to estimate because most people are not tested for the flu when they have it and because people may die of a combination of causes, including the flu. The usual estimate is that the regular seasonal flu causes about 30,000 deaths each flu season (the winter months), so these latest swine flu numbers aren’t too bad. In fact they’re well below the government’s estimate back in August of 30,000 to 90,000 deaths from swine flu this season.
The big question is what will happen in January/February – will swine flu reassert itself in a third wave, as happened in the pandemics of 1918 and 1957? Will the H1N1 virus change to become more lethal, or more resistant to the vaccine? If either of these things happens the situation could change quickly. Most people in the U.S. are not yet immune to the swine flu because they have not had it yet and they have not been vaccinated against it.
Apparently many people think the danger is passed. We’ll hope they’re right. But if you still haven’t gotten your swine flu shot, it’s not too late. The vaccine supply seems to be pretty good these days.
Thursday, December 10, 2009
No one is saying that these diseases are infectious, like mad cow disease. But according to the latest thinking, once an endogenous protein "goes rogue" and misfolds, it might then cause nearby normal proteins to misfold as well. Once the process starts it could become self-propagating, from one region of the brain to the next.
Wednesday, November 25, 2009
The USPSTF systematically reviews of the benefits and harms of a preventive care services, and then tries to come up with a net assessment. In the case of BSE, the USPSTF reviewed the latest published data and concluded that; a) regular BSE does not lower the mortality rate from breast cancer, and b) women who perform BSE tend to have more imaging procedures and biopsies than women who don’t. These procedures are expensive and are themselves associated with minor health risks, such as infection and increased exposure to radiation. Overall, the net risk/benefit ratio for BSE is on the side of net risk.
The recommendation against BSE is only for women who are not at increased risk for breast cancer. Women who are at increased risk should consult their physician.
Reference: U.S. Preventive Task Force. Screening for Breast Cancer: U.S. Preventive Services Task Force Recommendation Statement. Ann. Int. Med. 151:716-726, 2009.
Saturday, November 21, 2009
Now a team of researchers claims to have proved it, according to a news article. They report that just 20 minutes of transcendental meditation per day significantly lowers the risk of heart attack by 47% in a group of high-risk patients (African American patients with narrowed coronary arteries.)
The results have not yet been published in a peer reviewed medical journal, the point at which they generally are accepted by the scientific community. Personally, I’d feel better if one of the researchers were not from the Maharishi University of Management, an institution founded by the Indian guru who popularized transcendental meditation back in the 1960s. In addition, it’s not clear whether the results in this one group of high-risk patients would translate to other types of high-risk patients, or to persons at lower risk. Time will tell whether the findings can be duplicated by other researchers and whether other stress relaxation techniques have a similar effect.
Sunday, November 15, 2009
Caffeinated alcoholic beverages are marketed primarily to young people under such names as Max Vibe, Torque, and Evil Eye. Some promotional campaigns depict consumption of multiple drinks in conjunction with high-risk sports such as snowboarding and motocross biking. The action by the FDA comes after the agency received a letter from 18 state Attorneys General asking that the FDA use its authority to see that the products are removed from the market. The Attorneys General argue that caffeine can mask the effects of alcohol and could lead to increased risk-taking behavior.
The two largest manufacturers have already agreed to remove their products from the marketplace. It would not be surprising to see the others follow suit within 30 days.
Saturday, November 14, 2009
Fortunately, the technologies for harnessing energy from renewable resources continue to improve each year. It may take some time and effort, but what choice do we have? At current rates of consumption, known reserves of the non-renewable energy resources (coal, oil, and gas) will run out in less than a century.
Reference: Jacobson, Mark Z. and Mark A. Delucchi. A Path to Sustainable Energy by 2030. Scientific American pp. 58-65, Nov. 2009.
Monday, November 9, 2009
Why did consumers ignore the reports that supplements just didn’t work, but responded to a report of potential harm? Researchers speculate that reports of harm might have higher impact because of greater news coverage, or that some supplements (such as Vitamin E) might be recommended more often by physicians who are more likely to read and understand scientific reports, or even that it depends on the type of person who takes a particular kind of supplement, the purpose of the supplement, and the availability of alternatives.
Still, it must be discouraging for public health officials to learn that consumers aren’t getting the message, don’t believe the message, or just don’t care whether their supplements work or not.
Wednesday, November 4, 2009
There would be winners and losers in an ethanol-based biofuels economy, because water generally must be used locally, whereas ethanol is more easily transported. Agricultural communities with plenty of irrigation water and the ability to grow corn would benefit from an ethanol-based biofuel economy. Agricultural communities with marginal water supplies would be forced to choose how best to use their dwindling water supplies – for agriculture or for people? City dwellers generally would be in favor of ethanol production for fuel by others; they don’t use much water for agriculture anyway and so have nothing to give up. However, they are likely to react negatively to a run-up in food prices.
What do you think about producing ethanol from corn?
Saturday, October 24, 2009
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.
Thursday, October 22, 2009
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.
Monday, October 19, 2009
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.
Saturday, October 17, 2009
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.
Sunday, October 4, 2009
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, 5th 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”.
Saturday, October 3, 2009
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.
Thursday, September 24, 2009
Back in 2005, the U.S. Department of Agriculture conducted an environmental assessment of sugar beets that had been genetically engineered to resist the herbicide Roundup. They concluded that the new beets would have “no significant impact” on the environment, and therefore a full environmental impact statement would not be required. With that ruling, the beets were approved for widespread planting.
The new beets have been popular with farmers, and plantings have soared. But watchdog groups like the Center for Food Safety are not convinced that the Department of Agriculture should have approved the new beets so quickly. They have challenged the Department of Agriculture in court, and recently they won the first round; a Federal District Court judge in San Francisco has ruled that the Agriculture Department should have done an environmental impact statement before approving the beets for widespread planting. The judge in the case will decide on the correct course of action next month. But the plaintiffs have already said they would ask for a total ban on the biotech beets, according to an article in the New York Times this week.
Most consumers don’t seem to care; sugar is sugar.
Wednesday, September 16, 2009
In 2009 there was only a short window of opportunity before sea ice closed the route again for the year. But in 30 years the trans-Arctic shipping season could last for three months or more. The new Arctic route cuts nearly 40% off the distance traveled via the usual more southerly routes through either the Suez canal or the Panama canal.
Global warming, dwindling sea ice; good for shipping, bad for polar bears.
Tuesday, September 15, 2009
Consumers probably are not aware that the devices can be this inaccurate. The Food and Drug Administration (FDA) is understandably concerned, and it’s pressuring the international organization that sets standards for the devices to tighten up the standards - or else the FDA may do it for them.
But this raises an interesting dilemma. Re-engineering and manufacturing the devices would make them more accurate, but it could also increase their price – at least, that’s the manufacturer’s arguments against new standards for accuracy. And if an increase in price caused some people to stop using them altogether, have we really gained anything? There’s always a trade-off; always a choice to be made…..
Friday, September 11, 2009
The pharmaceutical industry helped to define osteopenia, and it also has the pills to treat it. Call me a skeptic, but I’m guessing they had an interest in seeing a lot of women diagnosed with the condition. Some doctors are suggesting that the drugs used to treat osteopenia are being over-marketed to younger post-menopausal women who may still be at relatively low risk for bone fractures. They argue that the benefits of the drugs used to treat osteopenia are exaggerated and the risks generally are downplayed. If you're still young, consult your physician before taking drugs to treat osteopenia. Otherwise you could be trying to treat a problem that you don’t really have yet.
REFERENCE: P. Alonso-Coello, et al. Drugs for pre-osteoporosis – prevention or disease-mongering? British Medical Journal 336:126-129, 2008.
Monday, September 7, 2009
It sounds like the beginning of a bad joke, but it’s not. Legitimate physiological and anatomical “gender confusion” can be caused by sex hormone imbalances, tissue unresponsiveness to sex hormones, genes that don’t turn on properly during fetal development, or even sex-determining genes located on the wrong chromosome (in rare cases, an XY male can develop the characteristics of a female).
Sports federations should develop rules that allow gender determination (for the purposes of sports competition) before an athletic event, not afterwards, in the public eye. One can only wonder about the emotional damage about to be done to young Caster Semenya.
Thursday, September 3, 2009
There aren’t any new weapons in the arsenal just yet, but some scientists remain optimistic. According to a recent article in Scientific American, strategies currently under development include: 1) developing “narrow spectrum” antibiotics that target just one bacterial species at a time, 2) preventing pathogenic bacteria from causing disease in humans without actually killing them, 3) searching among bacterial species for antibiotics that bacteria use against each other in nature, and 4) genetically modifying antibiotic-producing bacteria so that they can be grown easily in culture.
We’ll probably never win against the bacteria, but we can keep trying to stay one step ahead.
REFERENCE: C.T Walsh and M.A. Fishbach. New Ways to Squash Superbugs. Scientific American pp. 44-51, July, 2009.
Thursday, August 27, 2009
At what point in human evolution did the ability to taste bitter foods first appear? Recent DNA analysis of a bone of a Neanderthal (an extinct line of archaic humans) indicates that they possessed the bitter taster allele. Therefore, the ability to taste bitter foods probably evolved more than half a million years ago, before Neanderthals and modern humans diverged from a common ancestor.
Evolutionary biologists believe that the ability to perceive bitter taste may have discouraged early humans from eating bitter-tasting plants, some of which are toxic if ingested in large quantities.
Thursday, August 20, 2009
Using this technology, scientists have discovered that in just six years, one of the largest aquifers in India has lost a volume of water equal to a lake 30 feet deep and nearly 5,000 square miles in surface area. Most of the groundwater consumed in the region is used for agriculture. Nobody knows how large the aquifer really is or how long it would take to deplete it, but losses of this size just are not sustainable in the long run.
We can expect more of this kind of useful information as the satellite technique becomes more sophisticated. But will we choose to change our water use practices as a result of what we learn?
Saturday, August 15, 2009
Why doesn’t this study prove once and for all that “breast-feeding prevents cancer”? Because it only shows an association between breast-feeding and lowered cancer risk - cause-and-effect has not been proved. Perhaps women who choose to breast-feed are more health-conscious overall. Perhaps they exercise more or have a better diet, and that’s actually what lowered the cancer risk. Further research will be needed to tease out the details.
Wednesday, August 12, 2009
But the available scientific evidence suggests that running is not a risk factor for knee osteoarthritis, and may in fact keep you healthier later in life. In one study, runners were compared to age-matched non-runners over an 18-year period. There was no difference in the rate of development of osteoarthritis between the two groups. In another study, overall disability rates in runners increased at only one quarter of the rate seen in age-matched sedentary persons.
A major risk factor for knee osteoarthritis is not running per se; its having had a previous knee injury. That is why there is so much osteoarthritis among former N.F.L. football players and former soccer players. But if you’re a recreational runner and manage to stay injury-free, don’t worry about wearing out your knees – just keep running!
Thursday, August 6, 2009
Apparently they come from the spleen. The spleen stores up to ten times as many monocytes as there are in the bloodstream at any one time. When a tissue is injured the spleen releases its stored monocytes, which then migrate to the site of injury, develop into macrophages, and participate in the cleanup and repair process. It’s a pretty efficient use of resources, when you think about it - a virtual army of monocytes is kept on standby, ready to be deployed when needed.
Monday, August 3, 2009
The Rosenbaum case is just one example of the shadowy black market in human organs worldwide. The World Health Organization estimates that about 10% of the more than 60,000 kidneys transplanted each year come from living donors who have sold their kidneys strictly for money. The temptation is hard to resist, especially for donors from poor countries where the choice may come down to selling a kidney or selling a child. The practice is not even illegal in some countries (Pakistan is an example), and as a result those countries are rapidly developing thriving “transplant tourism” enterprises.
What, if anything, could be done about the shortage of organs for transplantation?
Saturday, August 1, 2009
Saturday, July 25, 2009
Now there’s an explanation. Apparently, for both condoms and withdrawal there’s a big difference between “perfect use” and “typical use”. If a couple actually uses a condom every time (no exceptions, folks), the annual failure rate is only about 2%. For withdrawal every time, the failure rate is about 4%. The problem is that in the heat of passion some couples “forget”, or convince themselves that not using a birth control method just this once won’t be a big deal. Under these more typical use conditions, the failure rates of condoms and of withdrawal are indeed closer to 20% per year.
If you’re going to rely on these contraceptive methods, don’t cheat!
REFERENCE: R.K. Jones. Better than nothing or savvy risk-reduction practice? The importance of withdrawal. Contraception 79:407-410, June, 2009.
Tuesday, July 21, 2009
Percocet and Vicodin are comprised acetaminophen plus a narcotic. According to the panel of experts, there is now sufficient evidence to conclude that high doses of acetaminophen over prolonged periods of time can cause liver damage.
It's worth noting that nearly all drugs, even some very good ones, can have unwanted side effects if they are abused.
You can read or see the news reports on the panel’s findings by Googling “FDA”, “Percocet”, and “acetaminophen”.
Sunday, July 19, 2009
Energy shots may also contain B-vitamins, amino acids and various plant extracts, but these aren’t likely to give you much of an energy boost despite the products’ claims. And then there’s the cost – upwards of $3 apiece.
If it’s a caffeine buzz you need, what’s wrong with plain-old maximum strength (200 mg) No-Doz? It was your grandfather’s drug of choice nearly 50 years ago for pulling an all-nighter, and it still works. Plus it only costs about 20 cents per dose.
Saturday, July 11, 2009
Now a new study reports that caloric restriction slows the aging process in primates, too. Macaque monkeys that have been on a calorie-restricted diet (by 30%) for the past 20 years are living longer and are healthier than their age-matched control counterparts. Excluding animals that died of non-age-related causes (accidents for example), 50% of the animals on a normal diet have died of age-related causes, compared to only 20% in the restricted-diet group. The calorie-restricted animals also have fewer age-associated diseases such as diabetes, cancer, and cardiovascular disease. The study is still ongoing.
Wednesday, July 8, 2009
Sunday, July 5, 2009
We need to keep an eye on this pesky bug. Who knows what it could do in North America NEXT flu season? For the latest information on swine flu (also now called Pandemic H1N1), see the World Health Organization website.
Wednesday, July 1, 2009
Taking this new mortality data into account and reviewing the graph in the essay in Human Biology, one wonders whether the range of “normal” weight shouldn’t be shifted about 3 BMI to the right. A word of caution, however; the shape of the weight-vs.-risk curve is likely to be different for every disease, age group, etc. It’s probably going to be impossible to come up with a perfect functional definition of overweight, no matter how much we’d like to.
Sunday, June 28, 2009
Some flu pandemics cause only mild symptoms and few deaths – others can be quite deadly. The best-known pandemics of the last century were the deadly Spanish flu of 1918 (20-40 million deaths), and the milder Asian flu of 1957 (1-4 million deaths) and Hong Kong flu of 1968 (also 1-4 million deaths). In contrast, the milder seasonal flu that many of us get nearly every year kills “only” about a quarter of a million people each year.
Pandemics are of concern to public health officials (and the public!) because the virus spreads so quickly and because the consequences of the spread cannot always be predicted in advance. Fortunately, it now appears that this pandemic will be no more deadly than the typical seasonal flu that many of us get nearly every year. Most people who become infected with Influenza A (H1N1) are recovering without the need for medical care. But it could have been otherwise, and that’s why health officials were so concerned at first and why they are still watching it closely.
The other flu we worry about is avian flu, also known as bird flu. Avian flu is VERY deadly in the few cases in which it has been caught from birds, but human-to-human transmission is still exceedingly rare.
Wednesday, June 24, 2009
Worldwide, only about a thousand children have been born from previously frozen eggs. In contrast, over 50,000 babies are born each year in the U.S as a consequence of in vitro fertilization and implantation (Human Biology 5th ed., p. 394). Obviously, the idea of older single women freezing their eggs has not yet caught on. But it just might!
See “Why I Froze My Eggs”, by Rachel Lehmann-Haupt. Newsweek May 11, 2009, pp. 50-52.
Tuesday, June 23, 2009
Normally, patients who need an organ transplant place themselves on the transplant list of one of eleven regional Organ Procurement Organizations (OPOs) in the U.S. Waiting times can vary. When an organ becomes available the regional OPO offers it to a patient already on its list, with the highest priority given to the sickest patients and those who have been on the list the longest time.
Most patients sign up for the transplant list at only one OPO, because insurance companies will only pay for an organ transplant performed in a person’s “home” OPO. Nevertheless, patients who are willing to pay for the transplant themselves (and with access to a plane so they can get to the hospital within six hours) can increase their odds for a transplant by placing themselves on the transplant lists of several different OPOs simultaneously. No one has said whether or not Mr. Jobs was on more than one list at the time of his transplant, or how long he waited for his new liver.
For a discussion of whether the current organ allocation system is fair, see “How Should We Allocate Scarce Organs?” in Human Biology 5th ed., pp. 368-369.
Thursday, June 18, 2009
Now researchers are attempting to do the experiment. Sponsored by USA Track & Field (USATF), the researchers are currently enrolling people who run at least 10 miles per week. Participants must agree to be assigned randomly to either the "stretch" or the "no-stretch" group and to adhere to the study protocol for three months. Runners in both groups are expected to report their injuries during the study period.
Runners can apply to be participants at www.usatf.org/stretchStudy/. So far several thousand runners have signed up, though not all of them have completed the study protocol and submitted their reports. The results will be made public as soon as enough runners have completed the protocol for there to be a statistically significant difference between the groups, or when enough data has accumulated to show that there is no difference. Ultimately, up to 10,000 runners may be needed.
Runners, this is your golden opportunity to contribute to the advancement of science.
Monday, June 1, 2009
As phosphorus supplies decline and as the world demand for agricultural fertilizers grows, we can expect fertilizer price spikes, phosphate shortages, and perhaps even disruption of food production. Countries with large phosphorus reserves such as Morocco will benefit economically. Morocco could be among the wealthiest nations in the world in 50-100 years.
Tuesday, May 26, 2009
In initial experiments the method removed up to 80% of the bacteria in small samples (10-20 ml) of blood. However, several questions remain to be unanswered: 1) Can the method be tooled up to cleanse the larger volume of blood in human patients? 2) Will reducing the bacterial or fungal load in a patient’s blood actually improve the patient’s recovery? 3) What might happen to the patient if a few magnetic beads are not removed from the blood before it is returned to the patient?
It may be awhile before we know if the method can be used safely and effectively to treat blood infections in human patients.
Saturday, May 16, 2009
An article on what to call this virus appears this week in Science.
Thursday, May 14, 2009
Could such a scenario be prevented? The article goes on to say that in the long run, maintaining the world’s food supply will require drastic action, including solving the global warming problem, conserving fresh water, and stopping the current rate of topsoil losses. Otherwise, we may all be fighting each other for the last scraps of food sooner (perhaps in just hundreds or thousands of years) than we think. It’s something to think about.
Reference: “Could Food Shortages Bring Down Civilization?” Scientific American pp. 50-57, May, 2009.
Friday, May 8, 2009
There have been plenty of reports in the popular press about swine flu, some true, some not. For example, initial reports of a very high death rate from swine flu had to be revised downward once it was determined that many of the deaths attributed to swine flu were not caused by H1N1. Still, a death rate of nearly 2 % in healthy adults is quite high for any flu virus. Two percent of the world’s population is how many million people???
For authoritative updates about swine flu, try the news section of a magazine such as Science (see this week’s report) or the website of the World Health Organization.
Friday, May 1, 2009
Modern humans who inhabited the area thousands of years later also made the same kinds of stone tools. Did modern humans interact with and learn from H. floresiensis, or did they develop the same tool-making techniques independently? No one knows for sure yet.
Monday, April 27, 2009
The answer is “NO”! This is a classic case of the common misunderstanding about the relationship between correlation and causation. Yes, there is a clear correlation between breast-feeding and a lower risk of diabetes and heart disease later in life, according to the study. But that is not proof that the act of breast-feeding is what reduces the risk. What if women who breast-fed their children are just more health conscious overall throughout life? What if they exercise more often, or have healthier diets?
A more correct headline would be “Breast-Feeding May Benefit Mothers, Study Suggests”. Indeed, the article itself goes on to say that some experts are cautioning that an association (between breast-feeding and health benefits) does not prove a causal relationship, and that more research would be needed to determine the exact cause of the effect (lower risk).
Friday, April 24, 2009
News articles on the upcoming change appeared in most major papers yesterday, including the Los Angeles Times.
Sunday, April 19, 2009
One percent per year is not fast enough for the heart to repair itself under natural conditions after a heart attack. But the fact that it occurs at all is giving researchers new hope. If future research were to improve our understanding of how cardiac muscle cell replacement is regulated, perhaps new drugs or treatments could be developed that would jump-start the process after a heart attack.
It could be decades before any patients are actually helped by the new findings, but that’s the way science goes…..a little breakthrough here, a little breakthrough there, and pretty soon there’s real progress!
Thursday, April 16, 2009
No one knows for sure. But well-meaning climate scientists who believe in tipping points warn of doomsday scenarios in an effort to get people to do something about global warming before it is too late. You’ve heard it all before - the Amazon rainforest will become grasslands; the polar ice caps will melt; the seas will rise several meters, flooding most of Earth’s populated areas; ecosystems will be disrupted. Some climate scientists worry that talk of tipping points could backfire. If a tipping point doesn’t happen within the next couple of decades, will people quit worrying about global warming altogether and decide it’s not worth doing anything about? Yawn! I’m bored with this whole subject…….
The best climate models can’t tell us yet whether or not there are tipping points. And therein lies the danger - there may actually be tipping points. Perhaps more likely is that lots of little tipping points in Earth’s complex climate system will add up to acceleration of global warming the higher the temperatures get.
For a recent news article on the subject, see “Among Climate Scientists, a Dispute Over ‘Tipping Points’”, The New York Times, Mar. 29, 2009.
Friday, April 10, 2009
A comparative study of the effectiveness of the new DNA test (HPV test) versus the Pap smear (cytologic test) in preventing cervical cancer deaths was conducted in India with funds provided by the Bill and Belinda Gates Foundation. After just eight years, the study showed that the DNA test reduced cervical cancer deaths by nearly 50% compared to the Pap test. Significantly, not one woman whose DNA test for HPV was negative died of cervical cancer during the study period.
Saturday, April 4, 2009
In 2005 scientists hit upon an ingenious method that takes advantage of a dark period in recent world history - the above-ground testing of nuclear weapons between the mid-1950s and 1963. Nuclear weapons testing resulted in a sharp spike in carbon-14 levels worldwide. The levels peaked in 1967 and have since declined as carbon-14 diffused and equilibrated with the atmosphere, the oceans, and the biosphere. Carbon is incorporated into the chemical components of all new cells, of course, including DNA. It turns out that the carbon-14 levels in nuclear DNA correspond very closely to the atmospheric levels at the time the DNA was synthesized. So by comparing the cells’ nuclear DNA carbon-14 levels to a chart of atmospheric cabon-14 levels each year, one can determine the cells’ birth date.
How does this help us determine cell turnover? Think about it: if all of the cells in a piece of tissue are the same age as the individual, then cells are not being replaced throughout life. But if the average cell age is much younger than the individual, then cell turnover must be relatively high. The scientists who developed the cell-dating technique report that neurons in the cerebral cortex (the most highly developed area of the brain) do not undergo significant replacement throughout life - you’re born with all the cortical brainpower you’re ever going to have. In contrast, cells lining the intestine are replaced frequently.
Wednesday, April 1, 2009
You may live to see polar bears become nearly extinct in the wild. On the bright side (if there is one), marine shipping could occur between the Atlantic and Pacific Oceans through the Arctic Ocean during the summer months.
Thursday, March 26, 2009
When the PSA test was first introduced in 1987, scientists thought it might lead to as much as a 50% reduction in prostate cancer deaths. But now it seems that it may not save lives after all. In a study of 77,000 U.S. men, the 10-year death rate from prostate cancer was the same in a group who had an annual PSA test for six years plus a digital rectal examination for four years, compared to a control group who were never tested over the same time period. The study may need to be continued out for another decade or so to determine whether the PSA test has any usefulness over the longer term, however.
How can a test that accurately detects prostate tumors not save lives? Apparently the answer is that most prostate cancers are so slow-growing that older men are likely to die of something else first, even if they do have a diagnosis of prostate cancer. For older men, skipping the PSA test altogether may someday be safe option.
By the way, a digital rectal examination is not some sort of digital readout. It's a physician’s gloved digit, or finger.
Friday, March 20, 2009
Knowing this, how might we prevent the next pandemic, or at least have some warning that it was coming? One intriguing possibility would be to keep a close eye on diseases that develop in humans who are in close contact with wild animals. To learn more, read “Preventing the Next Pandemic”, by Nathan Wolfe (Scientific American, April, 2009, pp. 76-81), and then check out the website of the Global Viral Forecasting Initiative. In fact you can download a .pdf file of the Scientific American article directly from the the GVFI website.
Sunday, March 15, 2009
President Obama’s executive order will permit federally funded researchers to use the hundreds of stem cell lines in existence today, as well as new stem cell lines created by private funding in the future. But there is still a prohibition in place, called the Dickey-Wicker Amendment of 1996, which prohibits federal funding for research “in which human embryos are created, destroyed, discarded, or knowingly subjected to risk of injury or death”. So while federally funded researchers will be able to use stem cell lines created by private funds (because they themselves did not destroy any embryos), they will still be prohibited from creating their own new cell lines from human embryos.
How long can the Dickey-Wicker Amendment can stand up in this new climate of stem cell research permissiveness? It's anybody’s guess. The debate continues…
Wednesday, March 11, 2009
A new approach is anti-latent therapy – therapy designed to prevent dormant viruses from staying dormant and hidden. The idea is to force any remaining dormant viruses to become active again so that they can be targeted and killed by suppressive therapy. A combination of anti-latent therapy and suppressive therapy just might wipe out an HIV infection completely. At least, that’s the idea.
Wednesday, March 4, 2009
The unresolved issue of whether would-be parents should be allowed to create designer babies is a train wreck waiting to happen. New York, for example, does not have laws against using PGD strictly for cosmetic purposes, so clinics such as Dr. Steinberg’s are free to promise what they will. Nevertheless, it’s a slippery ethical slope they’re on. The issue is discussed in Human Biology 5th ed., pp. 396-397.
Sunday, March 1, 2009
Friday, February 27, 2009
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.
Wednesday, February 18, 2009
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.
Friday, February 13, 2009
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.
Monday, February 9, 2009
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.
Thursday, February 5, 2009
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.
Sunday, February 1, 2009
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?
Friday, January 23, 2009
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
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
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
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
Monday, January 5, 2009
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?