Thursday, October 27, 2011

CDC Panel Recommends Gardasil for Boys

An advisory panel of the CDC recommended this week that boys between the ages of 11 and 12 should be vaccinated against Human Papilloma Virus (HPV) with Gardasil. Previously, the recommendation was that only girls should be vaccinated.

HPV is now the most common sexually transmitted disease - over 70% of all adults will be infected at some time in their lives. Most people recover without any ill effects, however chronic infection in some people can lead to cancer. Gardasil was recommended for girls when it became available in 2006, because chronic HPV infection was known at the time to be a leading cause of cervical cancer. But new information reveals that HPV is responsible for some cancers in men, too, including cancers of the penis, anus, and throat.

Health officials don’t expect a huge rush to vaccinate boys, however. Only about 30% of the girls of eligible age are fully vaccinated so far, despite the fact that the vaccine has been available for six years. Gardasil sparked controversy from the very start – it’s a vaccine against a sexually transmitted disease, and some parents worried that it encourages the notion of sexual activity at too young an age. Other parents are against all vaccinations. In addition, Gardasil is expensive – more than $400 for the full series of three required shots.

What do YOU think - should Gardasil be part of the standard vaccination regimen for all children?

Monday, October 24, 2011

Cell Phones and Cancer

Another study – this one from Denmark – has failed to show a causal link between cell phones and brain tumors.

In the Danish study, researchers correlated data from a Danish cancer registry with mobile phone contracts over a 13-year period, starting in 1982. The study includes nearly 360,000 cell phone users; its shear size is an important plus. However, a weakness is that the study only includes people with long-term phone contracts - those with corporate phones or without long-term contracts would be missed by their methodology. In addition, the study could not quantify cell phone use other than by the length of the contract. Nevertheless, it is one more study that seems to point toward no significant risk of brain tumors from long-term cell phone use.

And that’s reassuring to those of us who have used cell phones for some years now.

Thursday, October 20, 2011

Finally, a Malaria Vaccine

After 30 years of trying, scientists have finally developed a vaccine that works (partially) against malaria, a parasite that kills more than ¾ of a million people per year. The vaccine is only about 50% effective, but that’s still considered significant because there has never been an effective vaccine against any parasite, ever.

Research leading to the new vaccine was funded in part by more than $200 million from the Bill and Melinda Gates Foundation. Bill Gates himself announced the results of the first clinical trials this week at a meeting in Seattle, to coincide with an online publication in the New England Journal of Medicine.

Production of the vaccine will be in Europe, and the cost will be kept as low as possible. It will take time to ramp up production, but the hope is that by 2015 the vaccine may be available to tens of millions of children per year. Initial vaccination efforts will focus on Africa, where one in five children die from malaria.

Wednesday, October 19, 2011

Origin of the Australian Aborigines

Where did the native peoples of Australia (the Aborigines) come from? To find out, scientists analyzed the DNA genomic sequence of a lock of hair from an Australian Aborigine that was collected over 100 years ago, in which there is no evidence of contamination or mixture with Europeans’ genes. The results, published Science, show that the Australian Aborigines descended from humans who migrated out of Africa to Eastern Asia around 62,000 – 75,000 years ago, well before a second dispersion from Africa of the current modern Asians (25,000 – 38,000 years ago). In other words, the Aborigines did not diverge from the current population of Asians, but from a group that left Africa much earlier, settled in Australia, and then remained isolated from and unaffected by later migrations. If this is true, then the Australian Aborigines may be the oldest human population to continuously occupy a region outside of Africa.

Reference: Rasmussen, Morton et al. An Aboriginal Australian Genome Reveals Separate Human Dispersals into Asia. Science 334:94-98, Oct. 7, 2011.

Wednesday, October 12, 2011

Screening for Prostate Cancer

A government panel recommended last week that men over 75 not be screened for prostate cancer with the PSA blood test. Apparently a positive PSA test often leads to aggressive treatment that is probably not necessary and may actually do more harm than good. The panel also said that even for men under 75, the evidence for a net benefit from the test is still inconclusive, and therefore they no longer recommend routine screening of younger men, either.
The evidence for the panel’s decision is presented in a review article published in the Annals of Internal Medicine. The review summarizes the findings of six different research studies published from 2004-2011, one of which I highlighted in this blog previously (see this blog March 26, 2009)
The panel’s recommendations are likely to meet resistance from drug companies and some physicians and patients. We tend to fear cancer, and therefore we tend to treat it aggressively whenever possible. But most prostate cancers grow so slowly that they generally are not much of a threat. In fact, autopsy studies have shown that most men aged 85 actually had prostate cancer when they died – its just not what killed them.

Thursday, October 6, 2011

Australopithecus sediba – A Close Relative?

Newly discovered skeletons of a 2-million-year old member of the human family called Australopithecus sediba have piqued the interest of paleontologists. Some are suggesting that A. sediba may be a closer relative of modern humans than Australopithecus afarensis – the most famous skeleton of which is “Lucy”, who lived about 3.2 million years ago. Others are not so sure.

In five articles in the September 9 issue of Science, scientists describe some of the primitive and modern features of the brain, pelvis, hands, and feet of this transitional archaic human. The brain shows signs of reorganization, including an enlarged frontal lobe. The hand looks like that of a modern human’s, but it is attached to a long arm typical of species that still swing from trees. The pelvis has some, but not all, of the features of an upright-walker. And the lower leg, ankle, and foot are an odd mixture of primitive and modern features. A. sediba probably could walk upright, though it’s gait would have been significantly different from our own.

Regardless of where paleontologists ultimately choose to place A. sediba in the human ancestral tree, further analysis of the species will almost certainly add significantly to our understanding of the transition to modern humans.

Tuesday, October 4, 2011

Motor Fuel From Waste Biomass Material

A long-term goal of policymakers in the U.S. has been to reduce our reliance on imported oil for our gasoline needs. Producing ethanol from corn has been a partial solution, but in the long run it will not provide enough energy meet our needs. Furthermore, using farmland to produce fuel rather than food increases the price of food. But what if we could produce energy efficiently from waste biomass material, such as wood chips, corn stalks, or grass? There’s plenty of energy there; the technical problem has been to find an efficient way to unlock the sugars from cellulose, the main structural component of plant cells.

Researchers at a company called Renmatrix believe they have found the answer; treating waste biomass with supercritical water. Apparently when water is heated to over 374 degrees centigrade and pressurized to 217 atmospheres (about 3,200 pounds per square inch), it enters a “supercritical” state that is neither gas nor liquid, but something in between. Supercritical water has a density of only about 30% of that of liquid water, for example. When treated with supercritical water, the five- and six-carbon sugars in waste biomass material are broken off from cellulose and harvested for further conversion to motor fuels. The energy required to fuel the process comes from burning lignin, a material leftover from the process itself.

So far it’s only been done on a small scale with wood chips. But Renmatrix is opening a new research and development center in Pennsylvania with the goal of developing an industrial-scale process. This is one to watch.