Hypnotherapy Birmingham, UK withIan Evans Hypnotist and Therapist.Retrac Hypnotherapy Centre 23 Broad Rd, Acocks Green, Birmingham B27 7UX Tel: 0121 707 3588 |
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Nicotine's double link to cot death (NewScientist.com news service)09:30 10 September 02 New research suggests why babies whose parents smoke tobacco are more likely to die of Sudden Infant Death Syndrome, or cot death. The experiments show that nicotine produces a double whammy, not only directly disrupting a baby's breathing, but also disrupting the early development of the neural circuits that guard against the stopping of breathing during sleep. Hugo Lagercrantz, one of the researchers at the Karolinska Institute in Stockholm, Sweden says: "I think it is most dangerous to smoke during pregnancy, because nicotine may set the sensors that detect low oxygen levels wrongly. "If all pregnant women stopped smoking I think the incidence of SIDS could be reduced by at least 40 to 50 per cent in Sweden and the UK," he told New Scientist Nicotine stops new brain cells forming (NewScientist.com news service)17:05 15 May 02 Nicotine can kill brain cells and stop new ones forming in the hippocampus, a brain region involved in memory, says a French team. The finding might explain the cognitive problems experienced by many heavy smokers during withdrawal, they say. The team allowed rats to self-administer doses of nicotine daily for six weeks. At blood nicotine levels comparable to those found in smokers, they found the creation of new neurons in the dentate gyrus in the hippocampus was cut by up to 50 per cent. Cell death also increased. The implications for smokers and for those using nicotine gum or patches to help them give up are unclear, says Pier Piazza of France's National Institute for Health and Medical Research (INSERM) in Bordeaux, who was involved in the research. He thinks the loss of "neuronal plasticity" could cause cognitive problems, but the team did not test this in the rats. "That is the next step. But the hippocampus is involved in memory and neurogenesis seems to be involved in memory, so we might expect there would be an effect," he told New Scientist. Smoking can trigger infertility (NewScientist.com news service)12:34 16 July 01 Infertility can be triggered by toxic chemicals found in exhaust fumes and cigarette smoke. Polycyclic aromatic hydrocarbons (PAHs) have been shown to hasten the deaths of egg cells in women's ovaries. "The fact that these chemicals, which are ubiquitous in the environment, have these effects is worrying," says David Ozonoff of the Department of Environmental Health at Boston University. Thousands of tonnes of PAHs, which also cause cancer, are released into the air each year. It is known that smoking can cause women to undergo menopause early, and researchers have long pointed their fingers at the PAHs in cigarette smoke. To see whether the chemicals really do affect fertility, Jonathan Tilly and his colleagues at the Massachusetts General Hospital in Boston exposed mice to one PAH compound. They found that their eggs began to die off. The researchers discovered that the compound has this effect because it binds to a specific receptor on the outside of ovarian cells. This sends a signal that activates a gene called "Bax," a master regulator of cell suicide in ovarian cells, triggering a cascade of events that causes the cells to die. Tilly's team then tried to see whether the compound had the same effect on human tissue. The researchers grafted human ovarian tissue under the skin of mice, and gave the rodents a single injection of the PAH. Within a few days, egg cells in the human tissue had begun to switch on Bax and went on to commit suicide as well. The work shows that exposure to PAHs gradually leads the destruction of egg cells, Tilly says. But it may be possible to find ways prevent the receptors binding the toxin, he says. Journal reference: Nature Genetics (vol 28, p 355) Sylvia Pagan Westphal, Boston Masking effect (NewScientist.com news service)Short-term cognitive problems in smokers trying to kick the habit are well documented. "But there has been no good explanation for this," Piazza says. "It could be that while they are smoking, the stimulant effect of nicotine masks the loss in neuronal plasticity. When they stop smoking, these deficiencies remain."But Sue Wonnacott, an expert on nicotine at the University of Bath, UK, says: "There is a lot of redundancy in the brain and such deficits may or may not be sufficient to account for memory impairments. An alternative view is that memory impairments result from the subject feeling dreadful in the withdrawn state." Exactly how nicotine kills cells is not clear. Previous research on fetal exposure suggest it can induce apoptosis - programmed cell death - in immature cells. Piazza says it is possible that nicotine can kill cells elsewhere in the brain. But the dentate gyrus is one of only two regions known to form new - and so immature - neurons in the adult brain. Previous research has suggested that smoking might actually be beneficial for patients with a variety of diseases associated with brain cell loss. This is thought to be because nicotine can attach to receptors for acetylcholine, a neurotransmitter involved in memory. "I don't want to argue with findings that acetylcholinergic agonists - like nicotine - can be beneficial for Alzheimer's," says Piazza. "But now we have found that nicotine can also kill brain cells." Journal reference: Journal of Neuroscience (vol 22, p 3656) Smoking in pregnancy (NewScientist.com news service)
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