A single amino acid may solve two very different problems. For those who've been singing the burning numb foot blues, new study findings may soon have you humming a happier tune. A group of London researchers reported that the amino acid L-acetyl-carnitine, given in doses of 1,500 mg daily for six months, significantly improved symptoms of peripheral neuropathy. Even better, it regenerated nuke-nibbled nerves. And in another win for this amino acid dynamo, Dutch researchers report 100 percent success in treating six HIVers with lactic acidosis -- the most serious nucleoside-related toxicity -- with an intravenous combo of L-carnitine (1,000 mg twice daily) and B complex (4 ml twice daily of a formula containing 100 mg thiamine, 20 mg riboflavin, 100 mg niacinamide, 10 mg pyridoxine and 10 mg dexpanthenol). Not bad, considering that with the standard watch-and-wait approach, lactic acidosis has a 50 percent mortality rate.