Establishing the Japan-Store House of Animal Radiobiology Experiments (J-SHARE), a large-scale necropsy and histopathology archive providing international access to important radiobiology data

Purpose: Projects evaluating the effects of radiation, within the National Institutes of Quantum and Radiological Science and Technology (QST), National Institute of Radiological Sciences (NIRS), have focused on risk analyses for life shortening and cancer prevalence using laboratory animals. Genetic and epigenetic alterations in radiation-induced tumors have been also analyzed, with the aim of better understanding mechanisms of radiation carcinogenesis. As well as the economic and practical limitations of repeating such large-scale experiments, ethical considerations make it vital that we store and share the pathological data and samples of the animal experiments for future use. We are now constructing such an archive called the Japan-Storehouse of Animal Radiobiology Experiments (J-SHARE). Methods: J-SHARE records include information such as detailed experimental protocols, necropsy records and photographs of organs at necropsy. For each animal organs and tumor tissues are dissected, and parts are stored as frozen samples at -80 ˚C. Samples fixed with formalin are also embedded in paraffin blocks for histopathological analyses. Digital copies of stained tissues are being systematically saved using a virtual slide system linked to original records by barcodes. Embedded and frozen tissues are available for molecular analysis. Conclusion: Similar archive systems for radiation biology have been also under construction in the USA and Europe, the Northwestern University Radiation Archive (NURA), and STORE at the BfS, respectively. The J-SHARE will be linked with the sister-archives and made available for collaborative research to institutions and universities all over the world

Identification of preneoplastic lesions as mucin-depleted foci in patients with sporadic colorectal cancer.

In experimental models, mucin-depleted foci (MDF), formed by dysplastic crypts devoid of mucin production have been recognized to be correlated with colorectal carcinogenesis and to serve as preneoplastic lesions of colorectal cancer (CRC). In humans, there is only one report of identification of MDF in patients with familial adenomatous polyposis and CRC; however, the histological characteristics of human MDF are not discussed extensively in the report. In the present study, colonic samples from 53 patients with sporadic CRC were stained with Alcian blue and examined for the presence of MDF. Subsequently, the samples were examined for the presence of aberrant crypt foci (ACF) by methylene blue staining. We classified MDF into two categories: flat-MDF and protruded-MDF (having the characteristics of both ACF and MDF). We found a total of 354, 41 and 19 colonic mucosal lesions with a mean multiplicity of 44, 38.9 and 66.9 crypts (ACF, flat-MDF and protruded-MDF, respectively). The density of MDF was 0.0082 lesions/cm(2) . The ACF identified in sporadic CRC patients corresponded to hyperplastic or non-dysplasic lesions. However, MDF identified in these patients corresponded to low-grade dysplasia. In addition, we found that Paneth cell metaplasia and inflammatory cell infiltration were specific histological features of MDF. These histological characteristics are reported to be associated with the development of CRC. Therefore, our results indicate that MDF might represent preneoplastic lesions in human colorectal carcinogenesis

Lung cancer risk in mice after low-dose-rate irradiation

Especially, after the accident at TEPCO\u27s Fukushima Daiichi Nuclear Power Station, there are concerns about cancer risks due to low-dose radiation exposure. However, since the risk is overwhelmingly smaller than the risk due to lifestyle-related factors such as smoking, it is difficult to accurately evaluate it by an epidemiological method in which bias tends to be a problem. Therefore, the purpose of this study is to analyze the risk of lung cancer by low-dose-rate radiation.In this study, we initially analyzed the risk of lung cancers in B3C3F1 mice irradiated with gamma-rays at high-dose-rate (30 Gy/hour, total doses of 200 mGy to 4 Gy). A dose-dependent increase in the incidence of lung adenocarcinoma was observed. Interestingly, by pathological analysis, we found frequent occurrence of nuclear grooves (one of the nuclear atypia) in lung cancer cells from gamma-irradiated group compared with that of non-irradiated group. Currently, we are analyzing the risk for lung cancers in mice irradiated with low dose rate (6 mGy/hour) of gamma-rays. These results will be presented at the conference.第64回日本放射線影響学