Get a wriggle on
Scientists at Cardiff University in Wales are a step closer to treating male infertility with their latest discovery: adding a missing protein to infertile sperm can "kick-start" its ability to fertilise an egg and significantly increase the chances of a successful pregnancy. The team found that the sperm protein, called PLC-zeta, is transferred to the egg upon fertilisation and activates all the biological processes necessary for development of an embryo. Some forms of male infertility are due to defective PLC-zeta. In the lab, the scientists prepared active human PLC-zeta and injected it into an unfertilised egg. The egg responded exactly as it should at fertilisation, says lead researcher Professor Tony Lai, adding: "In the future, we could produce the human PLC-zeta protein and use it to stimulate egg activation in a completely natural way." The study was published last week in the journal Fertility and Sterility.
A choc to the system
The roots of chocolate temptation lies in an unexpected part of the brain previously linked with movement, according to new findings by researchers at the University of Michigan. In a study published last week in Current Biology, rats were injected with an opiate-like drug called enkephalin, which was delivered straight to a brain region called the neostriatum. The rats then gorged themselves on more than twice the number of M&M chocolates than they would otherwise have eaten. As they ate, enkephalin - produced naturally in the same brain region - surged, too. "The same brain area we tested here is active when obese people see foods and when drug addicts see drug scenes," says lead researcher Alexandra DiFeliceantonio. "It seems likely that our enkephalin findings in rats mean that this neurotransmitter may drive some forms of overconsumption and addiction in people."
What's the best way to keep your weight in check? Cut sugar-sweetened beverages out of your diet, says a new study published in the New England Journal of Medicine. Teens who did so for a year as part of the study by the New Balance Foundation Obesity Prevention Centre of Boston Children's Hospital maintained their body mass index and gained an average of 1.8 fewer kilograms than their peers in a control group who continued to consume sugary drinks. The teens in the intervention group received deliveries of non-caloric beverages for one year, as well as check-in visits and reminder messages from the researchers. However, in the second year of the study, in which there was no intervention, both groups of teens showed similar weight gain. These findings suggest that teens are likelier to make healthier choices (drinking non-caloric beverages) when they are more easily available to them. This probably applies to adults, too.
Safety in numbness
If you've got major surgery lined up, take heart: survival after a general anaesthetic and within 48 hours of surgery has greatly improved worldwide over the past 50 years, according to a report in The Lancet. The paper analysed data from 87 studies spanning more than six decades and involving more than 21.4 million anaesthetics given worldwide. The estimates suggest that although more operations are carried out on patients who are considered high-risk or who need more complicated surgeries now than in the past, the likelihood of dying after a general anaesthetic has dropped by roughly 90 per cent to 34 per million people. The risk of dying from any cause within 48 hours of surgery has also decreased by about 88 per cent to 1,176 per million. However, the researchers note that the greatest and most progressive decline has been in developed countries, and more must be done to reduce anaesthetic mortality rates in developing countries.