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31 August 2013 | NewScientist | 17 Swift treatment helps tots with HIV TIME is of the essence. Giving HIV-positive infants prompt treatment halves their risk of dying early in childhood. The finding builds on results earlier this year showing that a baby and 14 adults were effectively “cured” by early treatment. In 2005, Mark Cotton of Stellenbosch University in Cape Town, South Africa, began a study of 377 South African infants aged 6 to 12 months. One-third received no antiretroviral drugs until their immune system showed signs of weakening, in line with standard practice at the time. The others received the drugs at 7 weeks of age, on average. Of these, half were treated for 40 weeks, the others for 96 weeks. Five years later, 21 “delayers” had died, compared with 11 and nine in the two “early” groups. What’s more, 24 of the infants who had 40 weeks of treatment and 40 that received 96 weeks remain off medication (The Lancet, DOI: 10.1016/S0140-6736(13)61409-9). Current guidelines say babies can have antiretrovirals at 6 weeks of age, but most HIV- positive babies start treatment at 6 months, Cotton says. He hopes the findings will help change that. Mini ‘brains’ built in lab for the first time WHY rely on mouse brains to help us understand our most complex organ when you can grow a model of a human one? Tiny “brains” that include parts of the cortex, hippocampus and even retinas, have been made for the first time using adult cells reprogrammed to behave like stem cells. And already we have fresh insight into the early stages of brain development. Juergen Knoblich at the Institute of Molecular Biology (IMB) in Vienna, Austria, and colleagues took induced pluripotent stem (iPS) cells and gave them a mix of nutrients thought to be essential for brain development. The stem cells first differentiated into neuroectoderm tissue, the layer of cells that eventually become an embryo’s nervous system. This was then put into a gel scaffold to help the tissues develop a 3D structure. In less than a month, the stem cells grew into brain-like “organoids” 3 to 4 millimetres across and containing structures that corresponded to most of the regions of the brain. “If you FAMILIARITY may breed contempt, and it also makes it easier to ignore our nearest and dearest. The brain can focus on one voice in a noisy room. To find out if familiarity of the voice helps, Ingrid Johnsrude at Queen’s University in Kingston, Canada, recruited 23 married couples. Individuals were played two sentences simultaneously and asked to report back details about one of them, such as the colour and number mentioned. They did this correctly 80 per cent of the time when their spouse spoke the target sentence and a stranger spoke the decoy sentence. If strangers spoke both, the success rate dropped to 65 per cent. But if the target sentence was spoken by a stranger, and the decoy by their spouse, the success rate was 73 per cent. This suggests a familiar voice is easier to focus on than a stranger’s – and also easier to ignore. However, people in older couples were less able to ignore their spouse if he or she spoke the decoy sentence (Psychological Science, DOI: 10.1177/ 0956797613482467). Perhaps this explains why older people can struggle to hear in noisy places, or why so many claim to be selectively deaf. Spouses easier to hear... and ignore PHILIPPE LOPPARELLI/TENDANCE FLOUE provide the right nutrients, they have amazing capacity to self- organise,” says Madeline Lancaster, also at the IMB. The team have grown hundreds of organoids and many are still functioning after almost a year, including ones using iPS cells derived from a person with microcephaly – when the brain does not reach full size. This model showed that too few stem cells were produced in the initial stages of development, which led to a shortage of neurons (Nature, DOI: 10.1038/nature12517). Stone age chefs cooked with spice IN PREHISTORIC times, just as now, some liked it hot. Residues scraped from the inside of 6000-year-old pots show they were used to cook food seasoned with a peppery spice. “If you find the botanical remains of spices at a site, you don’t [normally] know whether they were used in food or whether they just came from plants growing nearby,” says Oliver Craig at the University of York, UK. So, although coriander seeds have been found at a 23,000-year-old site in Israel, we cannot be sure that the spice was used to flavour food. Craig and his colleagues have now found clear evidence that spices were intentionally added to food in northern Europe around 6100 years ago – the earliest known evidence of this in Europe, and perhaps anywhere in the world. They studied 74 pots from sites in Denmark and Germany. Residues scraped off the inner walls of the pots suggested they had contained meat or fish, and seeds of garlic mustard (Alliaria petiolata), a local plant with a strong peppery flavour but little nutritional value. “Often, we associate the arrival of farming with the first use of new plants and spices,” says Craig. But the prehistoric chefs at his study sites were hunter-gatherers. “[Spices have] probably always been part of our cuisine.” PHILIP WILKINS/GETTY For new stories every day, visit newscientist.com/news
