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Category: Health (page 9 of 27)

04.30.2013

AIDS vaccine fails

Scanning electron micrograph of HIV-1 budding (in green) from cultured lymphocyte

The past two weeks brought plenty of interesting science news, including the failure of a potential AIDS vaccine. From Popular Science:

The study, called HVTN-505, was begun in 2009, over the years enrolling over 2,500 volunteers. The vaccination process doesn’t actually involve any live or even deactivated HIV; instead, it starts with one that includes genetic material that’s simply modeled after the virus, to prime the immune system. Then comes the real vaccine, involving recombinant DNA (meaning, DNA from various sources) based on adenovirus type 5, a common cold virus that in this case has been disabled so it doesn’t actually cause a cold. Attached to those adenoviruses are artificial versions of HIV antigens. Antigens–the term is short for antibody generator–trigger an immune response, and these artificial antigens were designed to attack the three major HIV subtypes.

This technique had shown some mild success before; in a study in Thailand in 2009, it showed a 31 percent reduction in the HIV infection rate, which sounds good to me, but is apparently not enough to really do more than encourage further research. Unfortunately, that was as much success as this strategy ever saw.

04.15.2013

HIV testing by DVD

A recent paper in Lab on a Chip describes using a DVD player as a diagnostic tool. The researchers convert the optical drive into a laser scanning device that can count the number of CD4+ cells. From Phys Org:

Aman Russom, senior lecturer at the School of Biotechnology at KTH Royal Institute of Technology in Stockholm, says that his research team converted a commercial DVD drive into a laser scanning microscope that can analyse blood and perform cellular imaging with one-micrometre resolution. The breakthrough creates the possibility of an inexpensive and simple-to-use tool that could have far-reaching benefits in health care in the developing world.
“With an ordinary DVD player, we have created a cheap analytical tool for DNA, RNA, proteins and even entire cells,” says Russom. The so-called “Lab-on-DVD” technology makes it possible to complete an HIV test in just a few minutes, he says.
In a proof of concept demonstration, the researchers collected cell-type CD4 + from blood and visualized it using the DVD reader technology. Enumeration of these cells using flow cytometry is now standard in HIV testing, but the practice has been limited in developing countries.
HIV testing currently uses flow cytometry, which requires expensive equipment. If the DVD technique proves reliable, HIV testing can be done much more cheaply.

04.10.2013

vitamin d holds up under scrutiny

Vitamin D

Six studies confirm the health benefits of vitamin D

We often see headlines mentioning a chemical or vitamin has astonishing new health benefits, only to have those claims fall apart under more thorough investigation. Vitamin D is looking like it might be an exception. Science News highlights six studies on the vitamin’s health benefits:

  • An analysis of 24 clinical trials in children finds that kids getting vitamin D supplements had a 47 percent reduced risk of dental caries, researchers report in Nutrition Reviews.

  • A study of 242 healthy adults getting daily calcium supplements shows that those who also took modest vitamin D supplements of 800 IU per day saw their blood pressure decrease. Their top blood pressure number fell by 10 points on average after a year and their bottom BP number fell by four points. Writing in Nutritional Influences on Bone Health, the researchers also report that the vitamin D folks saw their heart rate decline from 74 to 70 beats per minute. The calcium-only group saw no improvement on average.

  • A 28-year study in which Danish scientists monitored the health of nearly 10,000 people finds that those who developed a tobacco-related cancer during that time had vitamin D levels at the study outset of 14.8 nanograms per milliliter of blood on average, compared with 16.4 ng/ml on average for everyone else. That report shows up in Clinical Chemistry.

  • BMJ reports in a review of 31 studies that pregnant women with vitamin D levels of less than 30 ng/ml had an increased risk of developing a complication such as preeclampsia or gestational diabetes.

  • Low vitamin D levels may hamper metabolism in blacks. A study in Nutrition Research finds that adult blacks averaged vitamin D of only 14.6 6 ng/ml compared with 25.6 ng/ml on average in whites. Blacks were also more likely to have insulin resistance, a condition in which cells fail to use the hormone insulin efficiently to process glucose. But when researchers compared groups with similar vitamin D levels, the differences in insulin resistance disappeared. That suggests that the higher burden of insulin resistance in blacks is at least in part the result of low vitamin D, they conclude.

  • Very low vitamin D might be linked to suicide risk. An analysis of military service members finds that people who committed suicide appear to have similar vitamin D levels on average compared with those who don’t. But a closer look finds that people with the very lowest levels, less than 15 ng/ml, were roughly twice as likely to commit suicide as people with vitamin D ranging from 17 to 41 ng/ml. That study appears in PLoS One.

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