New HIV cases in Australia have risen more than 40 per cent in the past five years, raising concerns that people are becoming lax about safe sex. And it's not only HIV that's on the rise. According to an annual survey by the National Centre in HIV Epidemiology and Clinical Research, reported cases of chlamydia rose fourfold during the decade to 2005, and new cases of gonorrhea almost doubled. Gay men accounted for about 70 per cent of the new HIV cases, AP reports.

Heart of the matter

Scientists have found a way to make rats' hearts regenerate, rather than scar, after a heart attack - but the drugs used can be harmful, triggering cancers and damaging the liver. As well, the rats were treated immediately after the attacks, whereas people usually sustain heart damage over time. Nonetheless, the US research is encouraging, WebMD reports. The researchers, from Children's Hospital Boston and the Novartis Institutes for Biomedical Research, are now trying to develop new drugs that have the same effect.

Happy days

About one in three people on antidepressants who have cosmetic surgery give up the medication afterwards - and it's not just because their self-esteem gets a boost, according to a small, one-year US study. The most common operations were breast augmentation, tummy tucks and face lifts. Team leader Bruce Freedman says 98 per cent of the patients, all middle-aged women, reported a marked improvement in self-esteem afterwards, and the number on antidepressants fell by more than 30 per cent, Reuters reports. 'So, it appears that it wasn't a self-esteem effect,' he says. 'It may relate to a separate effect on quality of life.'

Fat chance

Injections of a natural enzyme have successfully reduced the appearance of cellulite in a small group of overweight women in the US who took part in a six-month study. After one day, almost 80 per cent of the cellulite was no longer visible. This increased to almost 90 per cent after one month, but fell to 76 per cent by the end of the study. The women reported significant bruising during the first week. It's not clear what causes cellulite, WebMD reports, but it affects about 85 per cent of women, regardless of their weight.

Raising the bar

Scottish bar workers are significantly healthier less than a year after smoking was banned in confined public spaces. Before the ban, almost four out of every five bar workers who took part in the small study in Tayside, Scotland, suffered respiratory or sensory problems. One month after, the number fell to 53 per cent), and after two months to 47 per cent. As well, there was a marked improvement in lung function, and a lessening of airway inflammation, Reuters reports.

Stroke connection

The illegal drug meth-amphetamine seems to lessen brain damage in rats and gerbils that suffer strokes - and University of Montana researchers have no idea why. Sometimes called crank, crystal, speed or ice, methamphetamine is known to exacerbate stroke damage if administered before an attack, but small doses administered as long as 16 hours afterwards provided 80-90 per cent protection of neurons. 'Don't ask me how,' says researcher Dave Poulsen. 'We're trying to figure that out.' By contrast, leading clot-busting drug used for strokes must be administered within three hours, AP reports.

Jason Sankey is a tennis professional