[Distribution and changes in properties of ferromagnetic iron particles administered to the animal body]

The registration of ESR signals of organs and tissues in the wide range of temperatures permits to study properties and distribution of ferromagnetic particles in animal organisms. High dispersed powder (HDP) of iron (particle dimension--50-100 nm) was administered subcutaneously to mice in the doses 2 and 100 mg/kg weight of animals. One week after the administration HDP was accumulated in the animal organs under study. Two weeks after the treatment of mice with HDP in the dose of 2 mg/kg the ESR signals with g = 2.1 appeared in the animal tissues: liver, spleen, kidney, heart and lungs. Six weeks after the treatment the ESR signals of the studied tissues did not differ from those in control animals.