HISTOPATHOLOGIC EFFECTS OF RARE EARTHS ADMINISTERED INTRAPERITONEALLY TO RATS. A Preliminary Report

Intraperitoneal administration of the stable rare earths, cerium, lanthanum. yttrium, praseodymium, neodymium, and a commercial mixture C-340 at relatively high dosage levels resulted in an acute peritoneal reaction, which subsequently developed into a true granulomatous peritonitis. Ascites frequently accompanied the acute inflammatory reaction. Intraperitoneal administration of these rare earths occasionally resulted in focal hepatic necrosis. Review of our autopsy material from human patients treated at a much lower dose level failed to reveal definite evidence of similar histologic effects. (auth)