Abstract
A life-span study with 900 female virgin Han:NMRI mice (300 outbred controls, 300 of a fat subline and 300 of a lean subline) was carried out to determine the occurrence of spontaneous diseases with ad libitum or restricted feeding. Rare non-neoplastic lesions of the lungs (1-8%) were secondary inflammations, focal ossification and subintimal arterial 'plaques'. More frequent were age-dependent pulmonary mineralizations similar to psammoma bodies (3-18%) and crystal formations (4-22%). Food restriction did not affect the incidence of these lesions directly. Crystals were observed furthermore within infoldings of the tracheobronchial mucosa and intra- as well as extracellularly in the nasal cavities.