Biomedical subjects
Publications and source records attributed to S M Al-Douri.
The histological development of the teeth of mice homozygous for the osteopetrotic mutation microphthalmia (mi) in the mouse is described for the period 1-20 days post partum. The abnormalities described, including overall retardation, impaired root formation, encapsulation by bone and consequent non-eruption, are discussed and compared to the defects seen in the grey lethal (gl) mouse.
An ultrastructural study of the jaws of osteopetrotic microphthalmic mice (mi/mi) showed that both bone matrix and dentin were abnormal. In 5 days old mice, the number of osteoblasts was increased: in 15 days old mice, the number of osteocytes was decreased and many of the cells were dead or dying. Mutant osteocytes lacked osmiophilic laminae, calcospherites were irregular in size and density and collagen fibres were scarce and abnormally distributed. In mi/mi mice, the predentin layer of the incisor tooth was abnormally wide, the predentin-dentin junction irregular and patches of hypocalcified or uncalcified dentin were present.
Electron microscopy of the bone above the incisor of 10-day-old microphthalmic mice (mi) and incisors absent rats (ia) demonstrated that in both osteopetrotic mutants, osteoclasts indistinguishable from normal and with well-developed ruffled borders were present. Study of the same region in younger and older animals showed the type of abnormal osteoclast typical of the respective mutant strain.