PLASMA AND TISSUE-LEVELS OF SOME LANTHANIDE ELEMENTS IN HUMAN COLORECTAL LESIONS

Lanthanide (Ln) levels in plasma and tissues from colorectal patients and healthy subjects were determined by radiochemical neutron activati on analysis. Results, precision, accuracy and sensitivity am presented and discussed. Mean plasma levels of La, Ce, Nd, Eu and Yb were signi ficantly higher (p < 0.01) in adenoma and adenocarcinoma patients comp ared to control subjects. Increasing concentrations of plasmatic La, E u and Yb as well as Ln levels in tissue from healthy subjects, adenoma tous polyps, and adenocarcinoma (ADK) patients were observed. Measured tissue levels of Ln were constantly higher in ADK and adenomatous pol yps than in the adjacent normal tissues. These findings may reflect im paired calcium metabolism possibly involved in the early process of ca rcinogenesis leading to the development of ADK.