Of course, in the uphill battle against AIDS any discovery, even a disheartening one, counts as progress. The reasons why the virus never makes it from the urinary tract to the bloodstream, or how one gene could regulate, like a dimmer switch, the course of a disease –- those are answers that could one day lead to a vaccine. "It is going to be incredibly interesting," Dr. Gregory Stock at the UCLA School of Medicine told the New York Times. "We're entering a renaissance." And the chilling urinary-tract discovery already has a benefactor -- Calypte Biomedical Corp., which makes a urine test that detects the small traces of virus, was up $1 to 3 7/8 on the news in overnight trading. Sadly, there’s no shortage of customers.