News Feature: Building benchtop human models

The scientists inspect their “patient”; then, quite deliberately, they administer an overdose of the painkiller Tylenol. They watch over the next 24 h as the medicine attacks the liver. Levels of the amino acid tryptophan rise, indicating the organ is not working properly. Then production of bile acid drops, a sign of liver failure. This much Tylenol is like hitting the organ with a hammer, says Rashi Iyer, a toxicologist at the Los Alamos National Laboratory in New Mexico. “The liver falls apart.”