No abstract

Immobilization results in thinning of the articular cartilage and cartilage degeneration, although the exact mechanisms are not clear yet. Hypoxia is thought to contribute to the degeneration of articular cartilage. We investigated the roles of hypoxia inducible factor (HIF)-1alpha, vascular endothelial growth factor (VEGF), and the newly cloned antiangiogenic factor, chondromodulin-I (ChM-1), in cartilage degeneration in immobilized joints. Male Wistar rats (n = 30, 12-week-old) were divided randomly into the control group (n = 10), immobilization group (n = 10), and continuous passive motion (CPM) group (n = 10). In the immobilization group, the ankle joints were fixed in full plantar flexion with plaster casts for 4 weeks. In the CPM group, the ankle casts were removed during the immobilization period and the ankle joints were subjected to CPM. Significant thinning of the articular cartilage was noted in the immobilization group but not in the control or CPM group. In the immobilized group, vascular channels were found in the area between the calcified cartilage zone and the subchondral bone. The densities of HIF-1alpha-and VEGF-immunostained cells were higher in the immobilized group than the other two groups. In contrast, low expression of ChM-1 was detected in the articular cartilage of the immobilized group compared with the control and CPM group. Our results showed that immobilization induces thinning of the articular cartilage and appearance of vascular channel, in areas with balanced expression of HIF-1alpha/VEGF and ChM-1.

The strict class system in place during the Edo (early modern) period in Japan is thought to have encompassed customs that differed between the samurai (ruling class) and commoners. This study found that in samurai children, deciduous caries occurred only in maxillary incisors at 0.5-2 years of age and did not occur in the mandibular incisors and canines at 3-5 years of age. Conversely, in commoner children, deciduous caries occurred in all maxillary teeth and mandibular molars at 0.5-2 years of age and in all maxillary and mandibular teeth at 3-5 years of age. In commoner children, deciduous caries was seen in tooth types that have a low incidence of deciduous caries in modern Japanese. The present results show that deciduous carious lesions appear earlier and more frequently in the commoner children compared to the samurai children, probably because of differences in lifestyle between the two groups. There was no significant difference in the incidence of enamel hypoplasia in the deciduous dentition between samurai and commoner children, suggesting that the two classes had broadly comparable nutrition. In our previous study using the same skeletal series, similar results between samurai and commoners were found with respect to caries and enamel hypoplasia prevalence of the permanent dentition. Many of the samurai adults had slick polished teeth, which we believe were caused by regular brushing of the teeth in the samurai class. Such a custom might have functioned to prevent dental caries not only in the permanent dentition, but also in the deciduous dentition. Thus, oral hygiene practices in the samurai class are thought to have functioned to prevent dental caries not only in adults but also in children.

No abstract

The proportional relationships among the lengths of main limb bones comprising the humerus, radius, tibia and femur of the Jomon people are examined by means of comparison with those of the Kofun and recent Japanese. The disto-proximal indices (the radio-humeral and tibiofemoral) of the Jomon are significantly greater than those of the comparison ages, but the humero-femoral index, as a intermembral, is significantly smaller. Logarithmic plots showing the relation between each two bones, indicate no significant age differences among the inclinations of regression lines corresponding to allometry coefficients. However, significant age differences among the levels of lines were found. According to previous studies, there may be two factors affecting the proportions among limb segments, one biomechanical and the other thermal. The adaptation to mode of life, such as hunting of quick moving animals, appears to be a more reasonable interpretation of the relatively long distal segments (high disto-proximal indices) of the Jomon people.