Morphological features of the pulp cavity of maxillary first premolar teeth in different age groups were observed three dimensionally using micro-CT. Decreases in pulp cavity size and shape with age were clarified using a three-dimensional technique.
To describe the architecture and topohistology of the female perineal structures, especially the perineal membrane (PM), we examined frontal sections (one side) and horizontal or transverse sections (another side) of 15 bisectioned pelvic floors. The PM, notably comprising elastic fibers, extended mediolaterally or transversely on the immediately inferior side of the rhabdosphincter area. More posteriorly, the elastic fibers more tilted along the long axis of the vagina and became lining the lateral vaginal wall as a fibrous skeleton. The compressor urethrae and urethrovaginal sphincter were embedded in and interdigitated with the PM. The elastic fiber architecture of the PM was similar to the rectovaginal septum. We hypothesize that the PM plays a role of a shock-absorber at the interface between the levator ani and distalmost vagina. A standard diagram of the female perineal structures is necessary to be revised.
We investigated three-dimensional decrease in the volume of the pulp chamber caused by age-related secondary dentin formation using micro-CT and evaluated the applicability of the results to evaluation of age taking into account sex, age and tooth type. Decrease was slightly higher in females than in males, and a higher correlation between decrease and aging was observed in females. A comparison between age-groups revealed that decrease progressed between the fifties and sixties in males, and the forties and fifties in females. A stronger correlation between aging and decrease was observed in the mandibular central incisors than in the mandibular second premolars. This correlation was higher than other correlations between sexes and age-groups.
Desmin and vimentin are intermediate filaments that play crucial roles in the maturation, maintenance and recovery of muscle fibers and mesenchymal cells. The expression of these proteins has not been investigated extensively in human fetuses. In the present study, we examined the immunohistochemical expression of intermediate filaments in skeletal muscles of the head, neck and thorax in 12 mid-term human fetuses at 9-18 weeks of gestation. We also used immunohistochemistry to localize the expression of the myosin heavy chain and silver impregnation to identify the fetal endomysium. Expression of desmin and vimentin was already detectable in intercostal muscle at 9 weeks, especially at sites of muscle attachment to the perichondrium. At this stage, myosin heavy chain was expressed throughout the muscle fibers and the endomysium had already developed. Beginning with punctate expression, the positive areas became diffusely distributed in the muscle fibers. At 15-18 weeks, intermediate filament proteins were extensively expressed in all of the muscles examined. Expression at the bone-muscle interface was continuous with expression along the intramuscular tendon fibres. These results suggest that the development of intermediate filaments begins in areas of mechanical stress due to early muscle contraction. Their initially punctate distribution, as observed here, probably corresponds to the earliest stage of fetal enthesis formation.
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