EXPERIMENTAL AND CLINICAL-STUDIES ON THE ABSORPTION AND TOXICITY OF CERIUM NITRATE

In this publication we present the results of three studies concerning the toxicity and absorption of cerium. In the first experimental stud y in rats, following the application of a 2.2% solution of cerium nitr ate on dorsal wounds for five weeks, delayed healing was demonstrated and histological examination revealed richly vascularized granulation tissue in which microcalcifications and foreign-body type giant cells were found. A high concentration of cerium was found in the liver. The second experimental study employing rat enterocytes demonstrated an i mmediate cellular toxicity after exposure to a 2.2% cerium nitrate sol ution. Correction of pH and/or osmolarity did not play a protective ro le. In the clinical evaluation, significant levels of cerium were foun d in six blood samples and four urinary specimens, following the appli cation of a 2.2% cerium nitrate solution on burn wounds. Liver biopsie s were performed in two cases. There were no abnormal histological fin dings, but cerium levels were elevated.