We present nucleotide sequence data for mitochondrial DNA extracted from ancient human skeletons of the Yayoi era (ca. 2,000 BP) excavated from the Takuta-Nishibun site in northern Kyushu of Japan. Nucleotide sequence diversity showed that the Yayoi people of the Takuta-Nishibun site were not a genetically homegeneous population. This site shows a diversity in the burial style. Phylogenetic analysis indicated a statistically significant correlation between burial style and the genetic background of the Takuta-Nishibun individuals, and revealed no discrete clusterig patterns for the Yayoi individuals, for early modern Ainu, or for the Jomon people.

We extracted DNA from the human remains excavated from the Yixi site ( approximately 2,000 years before the present) in the Shandong peninsula of China and, through PCR amplification, determined nucleotide sequences of their mitochondrial D-loop regions. Nucleotide diversity of the ancient Yixi people was similar to those of modern populations. Modern humans in Asia and the circum-Pacific region are divided into six radiation groups, on the basis of the phylogenetic network constructed by means of 414 mtDNA types from 1, 298 individuals. We compared the ancient Yixi people with the modern Asian and the circum-Pacific populations, using two indices: frequency distribution of the radiation groups and genetic distances among populations. Both revealed that the closest genetic relatedness is between the ancient Yixi people and the modern Taiwan Han Chinese. The Yixi people show closer genetic affinity with Mongolians, mainland Japanese, and Koreans than with Ainu and Ryukyu Japanese and less genetic resemblance with Jomon people and Yayoi people, their predecessors and contemporaries, respectively, in ancient Japan.

To examine temporal changes in population genetic structure, we compared the mitochondrial DNA (mtDNA) sequences of three populations that lived in the same location, Linzi, China, in different periods: 2,500 years ago (the Spring-Autumn era), 2,000 years ago (the Han era), and the present day. Two indices were used to compare the genetic differences: the frequency distributions of the radiating haplotype groups and the genetic distances among the populations. The results indicate that the genetic backgrounds of the three populations are distinct from each other. Inconsistent with the geographical distribution, the 2,500-year-old Linzi population showed greater genetic similarity to present-day European populations than to present-day east Asian populations. The 2, 000-year-old Linzi population had features that were intermediate between the present-day European/2,500-year-old Linzi populations and the present-day east Asian populations. These relationships suggest the occurrence of drastic spatiotemporal changes in the genetic structure of Chinese people during the past 2,500 years.

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.

Gender and Hierarchical Differences in Lead-Contaminated Japanese Bone from the Edo Period: Tamiji NAKASHIMA, et aL Department of Anatomy and Anthropology, University of Occupational and Environmental Health, Japan-Objectives: We analyzed lead concentrations in bones from both genders of the Japanese samurai class and compared findings with those of the farmer and fisherman classes in the Edo period (1603-1867) to clarify gender and hierarchical (or occupational) differences in lead exposure during the Japanese feudal age. Methods: Tests were performed by atomic absorption. Results: Female samurai bones (30.5,ug Pb/g dry bone) showed higher lead concentrations than male samurai bones (15.6jg Pb/g dry bone), but these differences were not significant. This tendency was also seen in the farmer and fisherman classes (male: 1.0jg Pb/g dry bone; female: 1.7,ug Pb/g dry bone). Strong hierarchical differences between samurai and farmer/fisherman classes were seen in both genders in this study (p< 0.001). One of the female samples from the Samurai class, who was a daughter of the 6th feudal lord in Kokura (Japan), had 945.5 jig Pb/g dry bone. Conclusion: The samurai class were the aristocrats of society. We assume that facial cosmetics (white lead) comprised one of the main routes of lead exposure among the samurai class, because cosmetics were a luxury in that period. (J Occup Health 1998; 40: 55-60)

This study compares left ventricular global function in 55 patients (25 with hypertrophy and 30 without hypertrophy) with essential hypertension, whose blood pressure had been stable for longer than 1 year, with that in 35 healthy subjects. Left ventricular global function was calculated using the echocardiographic Doppler index as described by Tei et al. (Tei index). No significant differences were observed in echocardiographic left ventricular systolic function between the three groups. Left ventricular global function differed significantly between the three groups, however, suggesting impaired left ventricular global function even in the absence of left ventricular hypertrophy. Similar changes were observed in the ratio of peak velocity of atrial systole to peak velocity of early diastole during left ventricular inflow waveform (A/E), indicating that this disorder mainly reflects impaired left ventricular diastolic function. Unlike A/E, the Tei index is not affected by increasing age, and, therefore, is appropriate for evaluating left ventricular global function in hypertensive patients, most of whom are middle-aged or older. This index may be useful for determining treatment strategy and evaluating treatment effects.

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Lifestyle-Determined Gender and Hierarchical Differences in the Lead Contamination of Bones from a Feudal Town of the Edo Period: Tamiji NAKASHIMA, et al. Department of Anatomy, University of Occupational and Environmental Health, Japan-We analyzed lead concentrations in bones from both genders of Japanese merchants (including rohnin; masterless samurai) and farmer classes, and compared the findings with those of the samurai class in the Edo period (1603-1867) to clarify gender and hierarchical (or occupational) differences in lead exposure during the Japanese feudal age. Merchant class females had significantly higher lead exposure (90.8 µg Pb/g dry bone; n=20) than males of the same class (39.9 µg Pb/g dry bone; n=31) (p<0.01), indicating a remarkable gender difference in the urban population. In contrast to these high concentrations, males and females of the farmer class living in agricultural (or semi-rural) areas had significantly lower exposure (total mean value; 9.2 µg Pb/g dry bone; n=4) than both genders of the merchant class (p<0.001), and the gender difference was not significant in this class. (J Occup Health 2007; 49: 134-139)