Tamiji Nakashima

8-Hydroxydeoxyguanosine generated in the earthworm Eisenia fetida grown in metal-containing soil

Heavy metal pollution of soil causes biological problems, such as mutagenicity to living organisms, including human beings. However, few methods have been developed to assess metal mutagenicity in soil. To avoid metal mutagenicity, an adequate bio-monitoring method is required. In the present study, to determine if the analysis of oxidative DNA damage generated in the earthworm is a useful bio-monitoring method for soil mutagenicity, the accumulation of 8-hydroxydeoxyguanosine (8-OH-dG), a major form of oxidative DNA damage, in Eisenia fetida (Savigny, 1826) treated with cadmium chloride (CdCl2) or nickel chloride (NiCl2) was analyzed. E. fetida was treated with Cd (10 or 200 microg/g soil) or Ni (10 or 200 microg/g soil) for 1, 2, and 3 weeks or 3 months. After metal exposure, the metal concentration in E. fetida was analyzed by atomic absorption spectrometry and the 8-OH-dG accumulated in E. fetida was analyzed by HPLC analyses and immunohistochemistry. Atomic absorption spectrometry revealed that Cd, but not Ni, accumulated within E. fetida. The 8-OH-dG levels in the DNA of E. fetida treated with Cd for 3 months were significantly higher than those in control E. fetida. Moreover, immunohistochemical analyses revealed that positive signals for 8-OH-dG accumulation in seminal vesicles were detected only in E. fetida treated with 10 microg of Cd for 3 months. Although some points remain unresolved, a bio-monitoring system analyzing the DNA damage generated in the earthworm might be useful for the assessment of the mutagenicity of soil contaminated with various heavy metals, such as Cd.

8-Hydroxyguanine levels and repair capacity during mouse embryonic stem cell differentiation.

Abstracts To evaluate the defence capacities of embryonic stem (ES) cells against gene impairment, this study measured the levels of 8-hydroxyguanine (8-OH-Gua), a well-known marker of oxidative stress in DNA, and its repair capacity during differentiation. Undifferentiated ES cells (EB3) were cultured without leukaemia inhibitory factor (LIF) for 0, 4 and 7 days and are referred to as ES-D0, ES-D4 and ES-D7, respectively. These three cell lines were treated with 300 μM hydrogen peroxide (H2O2) for 48 and 72 h. After treatment, the amounts of 8-OH-Gua in the cells were determined by the high-performance liquid chromatography (HPLC)-electrochemical detector (ECD) method. The levels of 8-OH-Gua in ES-D7 treated with H2O2 were higher than those in ES-D0 and ES-D4, suggesting that the DNA in the undifferentiated cells was protected against gene impairment, as compared to that in the differentiated cells. To examine the repair capacity for 8-OH-Gua, this study analysed the expression of 8-OH-Gua repair-associated genes, 8-oxoguanine DNA glycosylase 1 (OGG1), MutY homolog (MUTYH) and Mut T homolog 1 (MTH1), in ES-D0, ES-D4 and ES-D7. The mRNA levels of MUTYH and MTH1 showed no significant change, whereas OGG1 mRNA was significantly decreased in ES-D7 treated with H2O2. Moreover, it was observed that ES-D7 treated with H2O2 readily underwent apoptosis, in comparison to its undifferentiated counterparts, ES-D0 and ES-D4. Taken together, ES cells are more resistant to DNA oxidative stresses than differentiated cells.

Symphalangism (two phalanges) in the digits of the Japanese foot

We report here an investigation into the number of phalanges of the 2nd to 5th toes in a Japanese population. The number of phalanges in each of these toes is normally three, distal, middle and proximal. However, occasionally only two phalanges are observed. In this condition, known as symphalangism, the middle and distal phalanges are fused (synarthrosis of the distal interphalangeal joint). The incidence of symphalangism in the 488 feet was found to be 72.5% in the 5th toe, 11.9% in the 4th toe, 0.8% in the 3rd toe, and 0.0% in the 2nd toe. No left-to-right or sex differences were observed. The reported overall incidence of symphalangism in the 5th toe of the foot in the Japanese population (74.7%) is significantly higher than that in the European population (40.2%). In the present sample, the incidence of symphalangism of the 4th toe (11.9%) was significantly higher than that in Japanese population samples previously studied (4.2%).

Lifestyle-determined gender and hierarchical differences in the lead contamination of bones from a feudal town of the Edo period.

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.

Gender and Hierarchical Differences in Lead-Contaminated Japanese Bone from the Edo Period

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

A rare case of complete proximal epiphyses (so-called pseudoepiphyses) of the metacarpal and metatarsal bones in the human

We report a rare case of complete proximal epiphyses (so-called pseudoepiphyses) of metacarpal and metatarsal bones in a human. These phenomena were seen in both the hands and feet of a seven-year-old girl undergoing medical examination for pain in the right foot. During medical treatment, X-ray photographs of the hands and feet were taken. Each metacarpal and metatarsal bone except for the first metacarpal bones had supernumerary epiphyses (complete pseudoepiphyses) at the nonepiphyseal end of these bones. This is a rare case even for an experienced orthopaedic surgeon.