Here's a look at your headlines for today's medical minute.

When it comes to kidney donation, you're never too old to give or receive.  New research found kidneys from donors older than 70 were still viable.  Scientists say using them would increase the available organ pool.

Night owls may be more prone to heart disease.  A new study found men who go to bed after midnight are more likely to suffer from arterial stiffening.  Several other large studies have linked chronic sleep loss to heart problems, diabetes and obesity.

A new report out of Spain suggests that THC - the active ingredient in marijuana -- appears to kill brain cancer cells. Researchers made the discovery after studying mice designed to carry human cancer tumors. Experts say the finding is worth more research, but patients shouldn't start lighting up just yet.