When Vito Oliveri first tried nitrous oxide in his twenties he didn't expect a legal drug that gives a quick high to temporarily paralyze him and his fiancée years later, leaving them unable to walk their four dogs. As recently as early last year, Oliveri, 34, who lives in Portland, Oregon, near some of the best ski resorts in the US, would often ski or take trips to the lakes with his fiancée, Emily Shuford, 30. "I'd typically be on the mountain on a Monday like today, but we just can't. Emily uses a cane and I probably can't walk...
