Preliminary study on dicentric chromosome identification algorithm based on artificial intelligence technology / 中华放射医学与防护杂志

Objective:To explore artificial intelligence technology and propose an algorithm for automatic identification of dicentric chromosomes to realize fast and high-throughput biodosimetry. In order to solve the time-consuming and laborious problem of manual analysis of dicentric chromosomes.Methods:Combining artificial intelligence technology and image processing technology, based on MATLAB software, algorithms like image preprocessing, threshold segmentation algorithm, binarization processing, area identification algorithm, convolutional neural network algorithm and double centripetal recognition algorithm were applied. A fuzzy membership function was defined to describe the degree of each chromosome belonging to a dicentric chromosome, and the discrimination threshold was set to realize the automatic identification of dicentric chromosomes.Results:Through the test on 1 471 chromosome images, compared with manual recognition, the detection rate of dicentric chromosomes cells of this algorithm reached 70.7%.Conclusions:This algorithm method carries out a preliminary study on the automatic identification of dicentric chromosomes with good result.

Research progress of chromosome translocation analysis in retrospective biological dose reconstruction / 中华放射医学与防护杂志

The application of chromosome translocation to retrospective biodosimetry for A-bomb survivors, the victims previously exposed to nuclear/ radiation accident has experienced nearly 40 years of development. Retrospective biodosimetry was internationally paid close attention to radiation workers, exposed atomic veterans and medical exposure subjects, respectively, along with the development of molecular cytogenetic technology such as mFISH and cGH. And the remarkable breakthrough and progress have been made in recent years. This paper reviews the progress of translocation indicator as retrospective biodosimetry for the subjects, in order to provide a reference for retrospective dose estimation based on translocation analysis.

Establishment of a biodosimeter model based on multiple gene expressions in human peripheral blood cells after 60Co γ-rays irradiation / 中华放射医学与防护杂志

Objective To investigate a potential radiation biodosimetry based on multiple gene expressions.Methods Human peripheral blood were exposed to 60Co γ-rays at doses from 0 to 8 Gy.The mRNA expression levels of 10 selected genes were detected 6 and 12 h after irradiation by RT-PCR.Individual variation was also examined.An optimal mathematical model of the dose response of these gene expression levels at each time point was obtained by the stepwise regression method.A blind test was conducted to validate the statistical accuracy of dose estimation.Results The 10 selected genes expression levels at each time point were significantly increased along with dose from 0.5 to 8 Gy (R2 =0.61-0.97,P ＜ 0.05).Individual variations were evident in the gene expressions of TNFSF4,PHPT1 and FDXR.The gene expression levels of PCNA,CCNG1,TNFSF4,PHPT1,GADD45A and FDXR were incorporated into the model at 6 h after exposure (R2 =0.88,F =54.8,P ＜ 0.001);the gene expression levels of PCNA,CCNG1,TNFSF4,MDM2,GDF15 and TNFRSF10B were included in the model at 12 h after irradiation (R2 =0.82,F =42.767,P ＜ 0.001).These two statistical models can be utilized for the dose estimation accurately.Conclusions The multiple gene expressions have a potential as a radiation biodosimetry.

Identification and Validation of Candidate Radiation-responsive Genes for Human Biodosimetr / 生物医学与环境科学（英文）

The aim of the present study is to analyze the global research trend of radiation-responsive genes and identify the highly reproducible radiation-responsive genes. Bibliometric methods were applied to analyze the global research trend of radiation-responsive genes. We found 79 publications on radiation-responsive genes from 2000 to 2017. A total of 35 highly reproducible radiation-responsive genes were identified. Most genes are involved in response to DNA damage, cell proliferation, cell cycle regulation, and DNA repair. The p53 signal pathway was the top enriched pathway. The expression levels of 18 genes in human B lymphoblastoid cell line (AHH-1) cells were significantly up-regulated in a dose-dependent manner at 24 h after exposure to 0-5 Gy 60Co γ-ray irradiation. Our results indicate that developing a gene expression panel with the 35 high reproducibility radiation-responsive genes may be necessary for qualitative and quantitative assessment after exposure.

Application of estimated biodosimetry to medical rescue during nuclear and radiation accidents / 军事医学

During medical rescue for nuclear and radiation accidents, triage of potential victims could contribute to better use of medical resources currently and higher efficiency of the rescue.Biological dose estimation techniques ( estimated biodosimetry) are effective for assessing the degree of external radiation injury.The application of estimated biodosimetry to triage is important for effective nuclear accident medical rescue.In this paper, the characteristics of the estimated biodosimetry and its application to triage during medical rescue for nuclear accident and radiation were discussed.

Biological dose estimation by cytokinesis-block micronuclei assay for victims in Taiyuan radiation accident / 中华放射医学与防护杂志

Objective To investigate the value of cytokinesis-block micronuclei(CBMN)assay in estimation of the biological doses of the victims of radiation accident.Methods Samples of peripheral blood were collected from the 5 victims(Subjects 1-5)at 16 h after the radiation accident of Taiyuan,Shanxi Province.And the peripheral blood samples and bone marrow sample were collected from the victim No.1 at 23 and 24 h after the radiation.Eight days after the accident Subject 1 underwent allogeneic peripheral blood hematopoietic stem cell transplantation.At difierent time points in the period of 1 year after the accident.peripheral blood samples were collected from these 5 victims.CBMN assay was conducted on the peripheral blood lymphocytes on the samples,and the biological doses were estimated based on the micronuclei(MN)frequencies.The nuclear division index(NDI)obtained from in vitro irradiation experiment using high dose of 60Coγ-rays was used to estimate the exposed doses for Subject 1. Dynamic arialysis of the MN frequency for the 5 victims was performed in the period of 1 year after the accident.Results The MN frequency of Subject 1 surpassed the value corresponding to the upper limit of the MN dose.effective curve.The dose range estimated bv the combination of the CBMN and NDI (CBMN+NDl)assay was 10-20 Gy for Subject 1.The doses estimated by MN frequency for Subjects 2,3,4,and 5 were 3.6,2.9,2.3,and 2.9 Gy,respectively.The estimated doses were in accordance with those estimated by physicat method.chromosome aberration analysis.and clinical symptoms.Prominent decrease of the MN frequency was observed at 26 d after the accident(18 d after the transplantation)for Subject 1(u=3.295,P<0.05).Gradual decrease of MN frequency was observed after the accident for Subjects 2,3,4,and 5.The MN frequencies 1 month after the accident of Subjects 3,4,and 5 were all significantly lower than those 16 h later(u=6.874,4.526,and 7.811,P<0.05).Conclusions Quick and accurate.CBMN assay reinforces and verifies the result of chromosome aberration analysis.The new index CBMN+NDI assay is of reference valne for estimating higher dose of irradiation.

Bioindicators in radiation protection

Biodosimetry is the evaluation of absorbed dose using bioindicators. Among chromosomal aberrations, scoring of dicentrics from peripheral human blood has been used as gold standard for biodosimetry, although in case of large scale incidents its use presents some drawbacks. Advances in technology have led to new investigations allowing or permitting the use of new methods which not only improve this "classical" biodosimetry but permits the design of other bioindicators making possible faster analyses, particularly in events where many persons may have been exposed. This report presents an overview of some recent studies developed by the "Grupo de Estudos em Radioproteção e Radioecologia - GERAR", Nuclear Energy Department of UFPE - Brazil, involving biodosimetry.

Biodosimetria pode ser definida como a avaliação da dose absorvida individualmente usando bioindicadores. Entre as aberrações cromossômicas, a quantificação de discêntricos em sangue periférico humano tem sido usada como padrão ouro in biodosimetria, embora essa técnica possua várias limitações em casos de incidentes envolvendo um grande número de indivíduos. Os avanços tecnológicos têm proporcionado novas ferramentas de investigações, resultando no desenvolvimento de novos métodos com intuito de otimizar essa dosimetria biológica "clássica", bem como na descoberta de novos bioindicadores, com o objetivo de possibilitar avaliação de exposição individual de forma mais rápida, em particular em situações envolvendo grande número de indivíduos expostos. Este texto apresenta um breve relato de alguns dos estudos desenvolvidos pelo Grupo de Estudos em Radioproteção e Radioecologia - GERAR, do Departamento de Energia Nuclear da UFPE - Brasil, associados ao emprego dos "clássicos" e novos bioindicadores em biodosimetria.

Biodosimetry for dose assessment of partial-body exposure: a methodological improvement

This study has explored the possibility of combining culture times with extending the duration for which Colcemid is present in cell culture in order to obtain better dose estimations following partial-body exposures. Irradiated and unirradiated blood was mixed to simulate a partial-exposure. Dicentric frequencies and resultant dose estimations were compared from 48 and 72 h cultures with Colcemid added at the beginning, after 24 h or for the final 3 h. The frequencies of dicentrics in first division cells increased with the cell culture time, providing better dose estimations. Unwanted excessive contraction of chromosomes caused by prolonged contact with Colcemid was measured and ways to avoid this are discussed. It is suggested that the combination of a lower than usual concentration of this drug combined with its earlier addition and longer culture time may provide metaphases better suited for interpreting partial-body exposures.

Este trabalho avaliou a estimativa da dose de radiação simulando uma exposição parcial do corpo através da irradiação in vitro de amostras de sangue misturadas com amostras não irradiadas. Foi observado que o prolongamento do tempo de cultura permite que a real fração de linfócitos em M1 contendo aberrações cromossômicas seja detectada, propiciando melhores estimativas de dose, sem a necessidade de correções matemáticas.