Separating the man from the mouse just got a bit tougher

It may become impolitic to ask if someone’s a man or a mouse. Scientists have succeeded in implanting testicular tissue—the sperm-making cells—from one species of animal into another. So the mouse ends up making the sperm of a goat. Or a pig. Or—maybe someday—a man. This achievement, reported on the journal Nature, probably means someone now can be born of human sperm extracted from human testes cells growing on a mouse’s back, for example. This technique soon could be used to salvage testicular tissue from men or boys facing chemotherapy or radiation for cancer. It’s an alternative to the deep-freeze sperm bank, and offers the first way to salvage a child’s sperm. A research team at the University of Pennsylvania and the University of Munster in Germany implanted the germ cells under the skin of ‘nude’ mice, which have no immune systems, so the sperm-making cells are not rejected. Small samples of testicular tissue from newborn mice, pigs and goats ‘‘were grafted under the back skin of castrated immuno-deficient mice. … Overall, more than 60 per cent of the testicular grafts from all three species survived,’’ some as long as 18 months, said researchers. Tests of mouse sperm produced from implants showed it was normal, active and made normal mice. Getting viable sperm from the goat and pig cells was more difficult, but did show the sperm can be used. These results ‘‘indicate that testis tissue grafting will be applicable to many different mammalian species,’’ including humans. (LATWP)

Even a few puffs risky for women

Light or non-inhaling smokers are damaging their health far more seriously than they may think, and women in particular are more at risk than men, a large-scale study of Danes has found. ‘‘There is an amazingly large risk of developing blood clots in the heart, or mortality, from smoking as few as three to five cigarettes a day,’’ said Dr Eva Prescott, head of the study. The study, carried out by the Danish Institute of Preventive Medicine, was begun in 1978 and has examined more than 12,000 people living in the Danish capital. More than half of the women and 70% of the men in the study were cigarette smokers. For women smoking three to five cigarettes a day the risk of a heart attack is more than double that of a non-smoker, the study showed. Risks were also increased for non-inhaling smokers. Women are more exposed to the risks of smoking because tobacco damages the female oestrogen hormone, which has a protective effect against cardio-vascular diseases. (Reuters)