This week’s news includes the surprising immune rejection of induced pluripotent stem cells, a WHO gathering to discuss the fate of two remaining stocks of smallpox virus, the use of AIDS drugs to prevent HIV transmission, Salmonella sweeping across US labs, the debate over why the blind have an improved sense of touch, and a trick used by tarantulas to keep from falling.
Stem cell setback
Because induced pluripotent stem (iPS) cells are made from a patient’s own skin cells and are thus genetically matched, scientists have assumed the cells would not trigger a patient’s immune response. But Yang Xu at the University of California, San Diego, and colleagues overturn this dogma, demonstrating that iPS cells trigger immune reactions when implanted into mice. In some cases, the implanted cells were completely destroyed by the mouse’s immune system. The immune response “is the same as that triggered by organ transplant between individuals,” Xu told ScienceNow. The study was published Friday (May 13) in Nature.
Destroying smallpox stocks
This week, health ministers from the World Health Organization’s member countries will gather to decide the fate of the last two known remaining stocks of smallpox virus. Scientists and health officials are divided over whether the final stocks of the virus should be kept for research into drugs and vaccines, in case of a reappearance of smallpox, or whether they should be destroyed to eliminate any risk of accidental outbreak.
The disagreement is a consequence of differing perceptions of risks and benefits among developed and developing countries, David Heymann, chairman of the board of UK Health Protection Agency, told Nature. Many poorer countries see smallpox research as a potentially dangerous luxury, he noted, while developed countries want to continue research due to fear that the virus could be used in a deliberate terrorist attack.
Preventing HIV transmission
A large, randomized trial involving over 1,700 couples in 9 countries has found that early antiretroviral treatment lowers an HIV-infected individual’s risk of transmitting the virus by 96 percent. The results, announced by the National Institute of Allergy and Infectious Disease last Thursday (May 12), were so convincing that an independent panel monitoring the research recommended they be released four years before the study had been scheduled to end, the Wall Street Journal reports. “The divorce between treatment and prevention is not real,” Michel Sidibé, head of the Joint United Nations Programme on HIV/AIDS, told ScienceInsider. “Treatment can reduce the number of new infections, which can increase the value of treatment.”
Salmonella hits US labs
An outbreak of lab-associated Salmonella infections is prompting health officials to examine laboratory safety protocols. Seventy-three infections across 35 states, tracked back to laboratories, caused illness and one death between August 2010 and March this year, the Centers for Disease Control and Prevention (CDC) reported on 28 April. Some of the infected individuals never visited a lab, but lived with someone who worked there, suggesting the lab worker carried the bacteria home on items of clothing or bags, the CDC’s Casey Barton Behravesh told Nature. It raises the question of whether use of this pathogenic Salmonella strain in teaching labs is necessary, he noted. For now, the outbreak seems to have ended, with the number of reported new infections dropping to the usual baseline of 0–4 per week.
An improved sense of touch
The blind have a better sense of touch than those with sight because of daily dependence on touch, not because the brain compensates for vision loss, new research suggests. Published on Wednesday (May 11) in the Journal of Neuroscience, researchers at McMaster University in Ontario found that blind participants outperform sighted individuals on all fingers, but blind Braille readers show particular sensitivity on their reading fingers, and both sighted and blind participants performed equally when the lips were tested for sensitivity. “There have always been these two competing ideas about why blind people have a better sense of touch,” said author Daniel Goldreich in a press release. “We found that dependence on touch is a driving force here.”
Tarantulas, large spiders that do not have the anchors that daintier spiders use to cling to vertical surfaces, shoot silk safety threads from their feet to reattach themselves to surfaces when they lose hold. The results, published in The Journal of Experimental Biology, support a 2006 paper that first suggested tarantulas release silk threads from their feet, a report that was refuted when another group found no evidence of the silk.
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