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Characterization of a Prematurely Condensed Ring Chromosome by FISH in Relation to Radiation Dosimetry
https://repo.qst.go.jp/records/67363
https://repo.qst.go.jp/records/67363fd80313d-b2b9-454c-8177-94a0e136458d
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2003-04-23 | |||||
| タイトル | ||||||
| タイトル | Characterization of a Prematurely Condensed Ring Chromosome by FISH in Relation to Radiation Dosimetry | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Kanda, Reiko
× Kanda, Reiko× Shang, Yi× Hayata, Isamu× 神田 玲子× 尚 奕× 早田 勇 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Recently, we have developed a new biodosimetry technique based on scoring drug-induced prematurely condensed ring chromosomes in human peripheral lymphocytes. It has advantages over conventional biodosimetry using metaphase analysis: it enables estimation of high-dose which induces G2 block, and can be easily performed in a short time in most medical facilities in cases of accidental exposure. In the present study, we characterized the PCC-rings in order to improve the accuracy of this new biodosimetry. Heparinized peripheral blood was obtained from a healthy donor and exposed to X-rays. Lymphocytes were then separated, cultured for 48 hours and treated with okadaic acid. Air-dried slides were made in warm and humid conditions and stained with Giemsa. In this study, condensed chromosomes were mainly of cells at late G2 to late M phases. We called cells that exhibit attached sister chromatids G2/M-PCC cells, and we called cells that exhibit separated sister chromatids M/A-PCC cells. In M/A-PCC cells, 10-20% of the rings lacked their own partner of sister chromatids, irrespective of exposed dose. However, this value usually increased to more than 50%; for example, when chromosomes of long-term fixed samples were spread by rather higher mechanical pressures. The ring yields of G2/M-PCC and M/A-PCC cells increased dose-dependently up to 20Gy. When each pair of rings or ring without a partner in M/A-PCC cells was counted as one aberration, the ring yields of G2/M-PCC and M/A-PCC cells at each dose were virtually the same. This finding is just as well for radiation dosimetry because both the data for G2/M and for M/A cells can be pooled. After observation by light microscopy, some slides were destained and hybridized with pan-centromeric probes. Yields of PCC rings having 0, 1 or 2 hybridized signals increased with dose up to 20 Gy both in G2/M and M/A cells. Among pairs of rings in M/A cells, the proportion of rings without hybridized signals significantly increased with dose. This is consistent with the finding from metaphase preparations .The rings without partners in M/A cells showed very distinct distributions of signals; the ratio of dicentric rings was significantly higher, while that of one-centric rings was significantly lower. Blood from a victim of the Tokai-mura criticality accident who was exposed to the equivalent of 3.0Gy of X-rays was used to examine the persistence of centric and acentric PCC-rings. The proportions of rings without hybridized signals tended to decrease with time in G2/M and M/A cells, although not significantly. As in the former experiment, the signal distribution of rings without partners was significantly different from those of other rings just after the accident. However, these differences were not significant at Day 420 after the accident. Regarding the different centromere distributions, the formation of rings without partners cannot be explained solely by artificial loss during chromosome spreading. Some might be formed by a sister chromatid exchange (SCE) between paired rings therby combining into one chromatid ring. In addition, the ring having district feature, which was called the Moebius ring of a chromatid and regarded as an indicator of SCE induced spontaneously in the papers of Sutou, was observed. It is very interesting that the single chromatid rings formed by SCE might be rare at 420 after the accident. The rings originated from SCE had 0 or 2 centromeres so that may be unstable through mitosis. The SCE induction by ionizing radiation (S phase-independent agent) has been a questionable matter for a long time. Many researchers reported that SCE are only induced in the first cell cycle following irradiation of BrdU-substitued cells, indicateing that radiation damages to BrdU lead to SCE. The present study using PCC techniques first evidenced the occurrence of radiation-induced SCE without the effects of agents to differentiate sister chromatids. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | International Symposium on Innovative Technology for radiation Risk Study 2003 | |||||
| 発表年月日 | ||||||
| 日付 | 2003-03-14 | |||||
| 日付タイプ | Issued | |||||
