Amourous Mice

No pill should be digested before its time — or it’s proper location, which sounds simple, but is nonetheless a challenge for drug makers. But a solution may be at hand: a magnetic addition to glycerin capsules could eliminate the problem of undigested pills.

In rats, an external magnet could hold the magnetized pills where they would be best digested in the intestine, according to a study in the Proceedings of the National Academy of Sciences. Prolonging that “intimate contact” between dose and intestine, as the researchers put it, could boost absorption of oral vaccines and medicines, such as agents for inflammatory bowel disease or GI cancers. Many drugs are optimally absorbed at specific sites in the intestine. The study wasn’t the first to try magnetic control, but it stood out in trying to make the process safer.

The system actively controlled the force between the pill and the external magnet, and it monitored the pill’s location with real-time videofluoroscopy.

Although it was safe in the rats tested, the researchers said they ultimately want to hone their pills’ magnetic attraction for use in the outpatient setting.

— Crystal Phend

Playing the Field Pays Off for Mice

Mice that mated with multiple partners gave birth to more fertile male offspring, according to an Australian study that provided the most compelling evidence yet of a hypothesized benefit of promiscuity.

Litters produced during a study of sperm competition exhibited a “significant paternity bias” favoring fathers from a polygamous lineage. Previous studies had shown that the ejaculate of polygamous males had a significantly higher sperm count and greater motility compared with ejaculate from monogamous male mice, as reported online in BMC Evolutionary Biology.

The findings support the hypothesis that higher sperm quality translates into a competitive advantage in reproduction, according to Renee Firman, PhD, and Leigh Simmons, PhD, of the University of Western Australia in Nedlands.

The investigators examined the concept of sperm competition through 12 generations of house mice. The studies compared two groups of mice: one in which females had access to multiple male partners and one in which each female had access to a single male partner.

Previous studies showed that females from the polygamous environment had larger litters, even though females in both groups were releasing the same number of eggs per cycle. Subsequent studies revealed the superior sperm quality among males from the polygamous lineage.

The final test was a mating competition, whereby female mice mated with one polygamous male and one monogamous male during ovulation. Firman and Simmons found that more than twice as many litters were fathered exclusively by polygamous male mice versus monogamous males (33 percent versus 14 percent). The remaining litters exhibited mixed paternity.