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In brief – Research news and discovery STEM cells could prove a double- edged sword in the treatment of diseases like leukaemia. Donna Forrest of the British Columbia Cancer Agency in Canada and her colleagues found that patients who had received bone- marrow transplants containing haemopoietic stem cells faced a 2.3 per cent risk of developing a secondary cancer, such as skin, lung, or breast cancer, over the drugs given following the procedure – rather than the transplanted stem cells themselves – were responsible for putting patients at greater risk of developing secondary tumours. However, Forrest warns, more studies are necessary to find out whether such treatments might influence cancer risk, especially as stem-cell transplants may eventually be developed to treat patients with conditions such as spinal-cord injury and heart failure. course of 10 years – nearly twice the risk of the general population (Cancer, DOI: 10.1002/cncr.22375). The team reviewed the medical records of more than 900 adult transplant recipients of this type, the vast majority of whom suffered from leukaemia. Given that bone-marrow transplants are known to increase leukaemia patients’ chance of survival, it is possible that the Cancer warning over stem cells COUNTER-INTUITIVE finding of the week: our richly complex marine world might never have come into existence if it weren’t for the greatest mass extinction of all time. The Permian extinction 251 million years ago wiped out 95 per cent of marine species. Palaeontologists had assumed that ecosystems grew steadily more complex since the first hard-shelled animals evolved about 540 million years ago, but Peter Wagner of the Field Museum in Chicago found something different when he examined data on 1176 marine ecosystems stored in the massive Paleobiology Database. Before the “great dying”, simple and complex marine ecosystems were equally abundant. Afterwards, complex ecosystems became three times as common – a ratio that has persisted ever since, Wagner says (Science, vol 314, p 1254). Life from death OUR galaxy may be surrounded by a swarm of invisible companions made of dark matter. After the big bang, dark matter should have formed a halo which then attracted ordinary gas to form stars and galaxies. When Jürg Diemand of the University of California, Santa Cruz, and his team modelled this process, they found that there should be at least 10,000 sub-haloes of dark matter within the halo of the Milky Way. Of these some 120 should have attracted some gas of their own and become dwarf galaxies. Only 15 dwarf companions of the Milky Way have been found. If the remainder have not become visible dwarf galaxies, they could still be detected by gamma-rays given off as the dark matter particles collide. Dark partners of the Milky Way “He has only forbidden you dead meat and blood, and the flesh of swine and that on which any other name has been invoked besides that of God.” (The Koran, 2:173) Muslim religious law requires, among other things, that an animal must be drained of blood before it is halal – permissible for consumption. Ritual slaughter according to Jewish dietary law – shechita – has the same prescription. Most Muslim slaughterers believe that drainage will only be complete if the throat of the animal is slit without stunning it first, but now Haluk Anil of the University of Bristol, UK, and colleagues have shown that the amount of blood drained from the animal, and the rate of blood loss, is the same regardless of whether or not it is stunned first. Anil’s team have already shown that stunning does not affect “bleed-out” in sheep. Now they have done the same thing in cattle. They measured the bleed-out in 13 cattle killed by the tradition Muslim method, and 13 killed in the same way, but having first been stunned by a captive-bolt- pistol blow to the head (Animal Welfare, vol 15, p 325). “Stunning does not impede blood loss, therefore this objection cannot be used any more,” says Anil, who is coordinating a European Union project to examine legislation and welfare issues related to religious slaughter, both shechita and halal. JONAS BENDIKSEN/MAGNUM 16 | NewScientist | 2 December 2006 www.newscientist.com Halal-standard slaughtering doesn’t need animals awake
