July 14th, 2009 by Nancy Brown, Ph.D. in Better Health Network
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In 2006 the Centers for Disease Control and Prevention (CDC) estimated that 1.1 million people were living with HIV, 4.4% of whom were 13 to 24 years old, and 48% of those youth are unaware they are infected. Using the Youth Risk Behavioral Survey (YRBS) data from 2007, the CDC estimated that about 12.9% of high school students had been tested for HIV.
The good news is that the highest risk teens were the ones getting tested more often, but only 22% of the highest risk teens had been tested.
To decrease the number of undiagnosed HIV infections among adolescents and promote HIV prevention, the CDC recommends that healthcare providers offer HIV screening as part of routine medical care for all people ages 13 to 64. People at high risk should be tested every year, including:
- Injection drug users;
- Anyone who exchanges sex for money or drugs;
- Sex partners of people with HIV;
- Men who have sex with men;
- Heterosexual people who have more than one partner since their most recent HIV test; and
- Anyone who gets a sexually transmitted disease.
High schools can support that effort by including information about HIV testing in the health curricula. People familiar with the benefits and process of the testing and counseling are more likely to be tested.
For teens, I usually suggest they go to anonymous testing sites in their community to be testing, so that the test is not including in their medical record. The anonymity also gives them a little extra courage. The trick is that they cannot lose their test number for the two weeks they wait for results.
This post, HIV Screening Should Be Offered As Part Of Routine Medical Care, Even For Teens, was originally published on
Healthine.com by Nancy Brown, Ph.D..
July 5th, 2009 by Medgadget in Better Health Network
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A team of Canadian researchers analyzed the air traffic patterns during March and April of this year, looking for correlation between departure/arrival cities of passengers and the spread of H1N1 swine-origin influenza. Turns out that the two are closely correlated and confirm that airports are gateways of pathogens as well as vacationing tourists.
Our analysis showed that in March and April 2008, a total of 2.35 million passengers flew from Mexico to 1018 cities in 164 countries. A total of 80.7% of passengers had flight destinations in the United States or Canada; 8.8% in Central America, South America, or the Caribbean Islands; 8.7% in Western Europe; 1.0% in East Asia; and 0.8% elsewhere. These flight patterns were very similar to those during the same months in 2007 (see Fig. 1 in the Supplementary Appendix). We then compared the international destinations of travelers departing from Mexico with confirmed H1N1 importations associated with travel to Mexico, and we found a remarkably strong degree of correlation. Of the 20 countries worldwide with the highest volumes of international passengers arriving from Mexico, 16 had confirmed importations associated with travel to Mexico as of May 25, 2009. A receiver-operating-characteristic (ROC) curve plotting the relationship between international air-traffic flows and H1N1 importation revealed that countries receiving more than 1400 passengers from Mexico were at a significantly elevated risk for importation. With the use of this passenger threshold, international air-traffic volume alone was more than 92% sensitive and more than 92% specific in predicting importation, with an area under the ROC curve of 0.97.
Letter to NEJM: Spread of a Novel Influenza A (H1N1) Virus via Global Airline Transportation
*This blog post was originally published at Medgadget*
June 18th, 2009 by Medgadget in Better Health Network
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Directly imaging dynamic biomolecular processes can reveal secrets which scientists have been trying to uncover in indirect ways. The interaction between various virus species and the immune system is one of those topics that would benefit from novel visualization techniques. Now researchers from the Howard Hughes Medical Institute have imaged, with considerable detail, a rotavirus as it is grabbed by an immune system molecule. The technique may allow the development of better vaccines against not only rotavirus, but open a large range of research possibilities in the life sciences.
In the new experiments, Howard Hughes Medical Institute (HHMI) researchers have mapped the structure of an antiviral antibody clamped onto a protein called VP7 that stipples the surface of rotavirus. The structural map reveals intimate new details about how the antibody interferes with VP7, a protein that helps the virus infect cells. The information may be useful in designing a new generation of rotavirus vaccines that could be easier to store and administer than current vaccines, said the researchers.
Rotaviruses replicate mainly in the gut, where they infect cells in the small intestine. The virus has a triple-layered protein coat, which allows it to resist being chewed up by digestive enzymes or the gut’s acidic environment. Rotavirus does not have an envelope covering its protein shell. A virus’ envelope helps it enter host cells, and viruses without envelopes face significant hurdles in penetrating the membrane of the cells they infect. “Since they have no membrane of their own, they must therefore perforate a cellular membrane to gain access to the cytoplasm (the interior of the cell),” [HHMI investigator Stephen C. Harrison] said.
The new research shows that as rotavirus matures inside an infected cell, it assembles a kind of “armor” coating made principally of VP7 and a “spike” protein called VP4. When the mature virus particle exits one cell to infect a new cell, it perforates the endosomal membrane of the target cell by thrusting in its VP4 spike like a grappling hook.
The virus’ ability to infect cells depends on a critical structural change that quickly removes the coat from the interconnected VP7 proteins — an event that unleashes the spike protein. Although researchers still do not know precisely what triggers the uncoating of VP7, they do know that it appears to happen when the virus senses a lowered concentration of calcium in its environment.
“VP7 sort of closes over VP4 locking it in place like the metal grills that surround a tree planted on a city sidewalk,” explained Harrison. “And it is the loss of VP7 in the uncoating step that triggers VP4 to carry out its task.”
To get a closer look at how antibodies latch onto VP7 and neutralize the virus, Harrison and his colleagues used x-ray crystallography to examine the molecular architecture of VP7 in the grasp of a fragment of the antibody. X-ray crystallography is a powerful tool for “seeing” the orientation of atoms and the distances separating them within the molecules.
Before Harrison’s team could use x-ray crystallography, however, they first had to crystallize VP7 in complex with the antibody fragment. Only after that step was completed, could they move on to bombarding those crystallized proteins with x-rays. Computers helped capture the diffraction patterns that emerged as the x-rays scattered from the crystal lattice. By rotating the crystallized protein complexes through multiple exposures, the researchers could record enough data to calculate three-dimensional models, which exposed the underlying architecture of VP7 and the antibody fragment.
The resulting detailed structural map of the VP7-antibody protein complex revealed that the antibody neutralizes the virus by preventing the VP7 proteins from dissociating, said Harrison. “Normally, calcium creates a bridge between VP7 molecules that holds them in place until uncoating,” he said. “Our structure revealed that the antibody makes an additional bridge, cementing the subunits together, making the virus resistant to the uncoating trigger and preventing it from infecting cells.”
Current rotavirus vaccines consist of weakened live virus that triggers the immune system to produce neutralizing antibodies. However, the new structural findings suggest how researchers might engineer a different type of rotavirus vaccine consisting only of immune-triggering protein, said Harrison. This protein-only vaccine could be made of a chemically linked complex of VP7 molecules that would stimulate the immune system more vigorously to produce anti-rotavirus antibodies.
While live-virus-based vaccines have been effective, said Harrison, they have drawbacks that a protein-based vaccine might overcome. The virus-based vaccines are perishable and require refrigeration, but vaccines based on proteins are more stable and can be stored at room temperature. Another benefit, said Harrison, is that protein-based vaccines could be combined with other protein vaccines in a “cocktail” that would cut down on the number of clinic visits since blending cannot be done so readily with virus-based vaccines. These advantages could make protein vaccines especially useful in developing countries that lack an extensive public health infrastructure and where the vast majority of childhood deaths from rotavirus occur, Harrison said.
HHMI press release: New Images May Improve Vaccine Design for Deadly Rotavirus
Abstract in Science: Structure of Rotavirus Outer-Layer Protein VP7 Bound with a Neutralizing Fab
*This blog post was originally published at Medgadget*
June 17th, 2009 by Peter Lipson, M.D. in Better Health Network, Quackery Exposed
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It might seem a bit undemocratic, but science, like medicine or dentistry, is a profession. One doesn’t become a scientist by fiat but by education and training. I am not a scientist. I apply science. My colleague Dr. Gorski is a scientist (as well as physician). He understands in a way that I never will the practical process of science—funding, experimental design, statistics. While I can read and understand scientific studies in my field, I cannot design and run them (but I probably could in a limited way with some additional training). Even reading and understanding journal articles is difficult, and actually takes training (which can be terribly boring, but I sometimes teach it anyway).
So when I read a newspaper article about science or medicine, I usually end up disappointed—sometimes with the science, and sometimes with the reporting. A recent newspaper article made me weep for both. Local newspapers serve an important role in covering news in smaller communities, and are often jumping off points for young, talented journalists. Or sometimes, not so much.
The article was in the Darien (CT) Times. The headline reads, in part, “surveys refute national Lyme disease findings.” Epidemiologic studies, such as surveys, are very tricky. They require a firm grounding in statistics, among other things. You must know what kind of question to ask, how many people to ask, how to choose these people, etc, etc, etc. So what institution conducted this groundbreaking survey on Lyme disease?
Actually, they are quoting the famous work of one Kent Haydock, chairman of the Deer Management Committee. But I’m sure he outlined his methods carefully. Or not.
Haydock conducted:
[T]wo surveys — which polled 41 Darien households after a showing of the Lyme Disease film, Under Our Skin, at the Darien Library last month… . In the 41 households that completed the questionnaire, 47 total Lyme disease cases were reported. In 64 percent of those cases, the patient had relapses after an initial Lyme treatment, which required additional treatment for a chronic or long-term conditions.
So, Haydock showed the agitprop chronic Lyme advocacy film Under Our Skin to local families, presumably not selected at random, and then asked them if they had signs of Lyme disease and if it was ruining their lives. Not surprisingly, the answers to both questions were “yes” a remarkably high percentage of the time.
His conclusion: the surveys “show that Lyme not only exists in great numbers, but also in debilitating, chronic and long-term cases.”
This is not epidemiology. This is not science. This is an uninformed opinion dressed up with meaningless numbers. If you get together a group of people who are interested in Lyme disease, show them a propaganda film, and query them about it, the only thing you’ve “measured” is your ability to count people who come to a movie and hold a certain belief. If there were any valid conclusions to be drawn (and with these numbers, there probably aren’t) it’s that many people in this small group think they have Lyme disease—and even that’s over-reaching.
It’s bad enough that the deer commissioner did this. But arguably, it’s much worse that the reporter and editor published it. The only thing this accomplishes is fanning the fears of the readers.
*This blog post was originally published at Science-Based Medicine*
June 15th, 2009 by Paul Auerbach, M.D. in Better Health Network, Health Tips, News
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Summer has arrived and so many of us are headed for the beaches that line the coasts of the United States as well as those of our inland waters, such as lakes and rivers. There are plentiful healthcare concerns for beachgoers. These include sunburn, drowning, jellyfish stings, sprains, strains, and cuts and bruises. What perhaps doesn’t receive as much attention as it deserves is ocean water quality – specifically, whether or not the water is contaminated by environmental toxins and/or harmful bacteria.
Nearly a year ago, reports circulated in the press that indicated that at least 7% of beach water samples in the U.S. exceeded acceptable (from a health perspective) levels of bacteria. A writer for the New York Times reported, “The number of beach closings and health warnings issued to swimmers as a result of pollution fell in 2007 from a record level in 2006,” according to the Natural Resources Defense Council (NRDC). But the writer continued that the NRDC noted “that American beaches ‘continue to suffer from serious water pollution that puts swimmers at risk.'” He cited that the NRDC analyzed “data obtained from the Environmental Protection Agency on more than 3,500 beaches,” revealing “that beaches across the country closed because of pollution or issued pollution-related health advisories for a total of more than 22,000 days in 2007, down from more than 25,000 days in 2006.”
A reporter for the Los Angeles Times wrote that the NRDC found that “Los Angeles County is home to the dirtiest beaches in the state (California), with repeat offenders Avalon on Santa Catalina Island and Santa Monica among those with the highest levels of fecal bacteria in ocean water.” Overall, the NRDC found that, “Illinois has the most coastal beaches in the country with water samples exceeding acceptable levels of (potentially harmful) bacteria, such as E. coli.”
The NRDC posts an informative page on beach pollution. The major takeaway is that the beachgoer should be well aware of the current situation with regard to pollution or contamination of any body of water for which human entry is contemplated.
Here is the status of the federal Beach Protection Act of 2008, as reported by OpenCongress:
Read more »
This post, Contaminated Beachwater May Be Hazardous To Your Health, was originally published on
Healthine.com by Paul Auerbach, M.D..
