Around a hospital's intensive-care unit it is often called the spiral of death. Chemotherapy or an infection knocks a patient's kidneys out of service, and within a day or two, inflammation spreads throughout his or her blood vessels. Blood pressure crashes, starving the body of oxygen, and in short order the lungs, liver, and other organs begin to fail. Replacing the kidney's most basic function by using conventional dialysis to clear urea and other wastes from the blood is of little help. More than half of those caught in the grip of acute kidney failure die.

But in a small clinical trial completed last winter, a novel treatment offered the first real hope for patients in acute kidney failure. Six out of the 10 critically ill patients beat the odds and survived; all but one had been judged to have no more than a 10 to 20 percent chance of living.