Localization of radiomagnesium in puppies: radioautographic study of heart and bone

¹ Department of Medicine, State University of New York Downstate Medical Center, Brooklyn, New York; and Medical Division, Oak Ridge Institute of Nuclear Studies, Oak Ridge, Tennessee

Densitometer scans were made of radioautographic images of puppies' hearts and bones produced by magnesium 28. The puppies' renal pedicles were ligated prior to intravenous injection of radioactive magnesium. The puppies were killed 15–20 hr after injection. The densitometer scanning of the heart radioautographs showed the highest densities present in the interventricular septum followed by the left and right ventricular walls. These data are in agreement with those reported for radioassay of magnesium 28 in the heart. The radioautographic images of femurs of puppies showed highest densities produced by magnesium 28 present in the epiphyseal line. Assays for magnesium 28 confirmed that the epiphyseal line contained higher concentrations of the radioisotope than did the diaphyses or epiphyses. There was no statistically significant difference between concentrations of radiomagnesium in epiphyses and diaphyses. Binding of magnesium to protein was found to be 16.3% when determined by ultrafiltration through cellophane.

Note:
With the Technical Assistance of Mary Bianchi and Martin Yarbrough