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Journal Articles

Modern radiation chemistry (Applications), 16; Computer simulation study of initial process of radiation biological effect

Watanabe, Ritsuko*; Kai, Takeshi; Hattori, Yuya*

Radioisotopes, 66(11), p.525 - 530, 2017/11

To understand the mechanisms of radiation biological effects, modeling and simulation studies are important. In particular, simulation approach is powerful tool to evaluate modeling of mechanisms and the relationship among experimental results in different spatial scale of biological systems such as DNA molecular and cell. This article summarizes our approach to evaluate radiation action on DNA and cells by combination of knowledge in radiation physics, chemistry and biology. It contains newly theoretical approach to estimate physico-chemical process of DNA damage induction in addition to typical method of DNA damage prediction. Outline of the mathematical model for dynamics of DNA damage and cellular response is also presented.

Journal Articles

Evaluation of DNA damage induced by Auger electrons from $$^{137}$$Cs

Watanabe, Ritsuko; Hattori, Yuya; Kai, Takeshi

International Journal of Radiation Biology, 92(11), p.660 - 664, 2016/11

 Times Cited Count:2 Percentile:25.63(Biology)

To understand the effect of internal exposure of $$^{137}$$Cs, we focus on estimation of microscopic energy deposition pattern and DNA damage induced by directly emitted electrons (beta-rays, internal conversion electrons, Auger electrons) from $$^{137}$$Cs. Monte Carlo track simulation method was used to calculate the microscopic energy deposition pattern. To simulate the energy deposition by directly emitted electrons, we considered the multiple ejections of electrons after internal conversion. Induction process of DNA strand breaks and base lesions was modeled and simulated using Monte Carlo methods for cell mimetic condition. The yield and spatial distribution of simple and complex DNA damage were calculated for the cases of $$gamma$$-rays and electrons from $$^{137}$$Cs. The simulation showed that significant difference of DNA damage spectrum was not caused by the difference between secondary electron spectrum by $$gamma$$-rays and directly ejected electron spectrum. The result support that the existing evaluation that internal exposure and external exposure are almost equivalent.

Journal Articles

Cellular automaton-based model for radiation-induced bystander effects

Hattori, Yuya; Yokoya, Akinari; Watanabe, Ritsuko

BMC Systems Biology (Internet), 9, p.90_1 - 90_22, 2015/12

 Times Cited Count:14 Percentile:69.16(Mathematical & Computational Biology)

The radiation-induced bystander effect is a biological response observed in non-irradiated cells surrounding an irradiated cell, which is known to be caused by two intercellular signaling pathways. However, the behavior of the signals is largely unknown. To investigate the role of these signaling pathways, we developed a mathematical model to describe the cellular response to direct irradiation and the bystander effect, with a particular focus on cell-cycle modification. The analysis of model dynamics revealed that bystander effect on cell cycle modification was different between low-dose irradiation and high-dose irradiation. We demonstrated that signaling through both pathways induced cell cycle modification via the bystander effect. By simulating various special and temporal conditions of irradiation and cell characteristics, our model will be a powerful tool for the analysis of the bystander effect.

Journal Articles

A Mathematical model of radiation-induced responses in a cellular population including cell-to-cell communications

Hattori, Yuya; Suzuki, Michiyo; Funayama, Tomoo; Kobayashi, Yasuhiko; Yokoya, Akinari; Watanabe, Ritsuko

Radiation Protection Dosimetry, 166(1-4), p.142 - 147, 2015/09

 Times Cited Count:4 Percentile:40.75(Environmental Sciences)

Cell-to-cell communication is one of the important factors to understand the mechanisms of radiation-induced responses such as radiation-induced bystander effects at low doses. In the present study, we propose simulation-based analyses of the intercellular signal transmissions between the individual cells in the cellular population. We developed the transmissions of two types of signals, i.e., X is transmitted via culture medium and Y is transmitted via gap junctions based on the diffusion equation. To observe the cell cycle as the response of cell induced by the signals, X and Y, we represented the cell cycle as a virtual clock including several check-point pathways and the cyclic process (G1, S, G2, M phases). The cellular population was divided into the grids (cells), and the signals and the clock were calculated for each grid. The signals, X, Y, were transmitted to the cells and stopped the clocks at the check points. Furthermore, the radiation was modeled as the radiation signal, Z, which affected the clock and the signals, X and Y. We input the radiation signal, Z, to specific cells, and simulated the behaviors of the clock of each cell and signals, X and Y. We will discuss the usefulness of our model for investigating the mechanisms of radiation-induced responses of the cell cycle via cell-to-cell communications.

Journal Articles

Responses of the salt chemotaxis learning in ${it C. elegans}$ mutants to microbeam irradiation

Sakashita, Tetsuya; Suzuki, Michiyo; Hattori, Yuya; Ikeda, Hiroko; Muto, Yasuko*; Yokota, Yuichiro; Funayama, Tomoo; Hamada, Nobuyuki*; Shirai, Kana*; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 74, 2015/03

An increasing body of data indicates that ionizing radiation affects the nervous system and alters its function. Recently, we reported that chemotaxis of ${it C. elegans}$ during the salt chemotaxis learning (SCL), that is conditioned taste aversion to NaCl, was modulated by carbon ion irradiation, i.e. accelerated decrease in chemotaxis to NaCl during the SCL. However, we had no direct evidence for the interaction of ionizing radiation with the central neuronal tissue (nerve ring) in ${it C. elegans}$. Microbeam irradiation is useful to analyze direct radiation effects at a cellular or tissue level. Thus, we applied the microbeam irradiation of the ${it C. elegans}$ nerve ring and examined the effect on the SCL.

Journal Articles

Effects of carbon-ion microbeam irradiation on locomotion and pharyngeal pumping motion in $textit{C. elegans}$

Suzuki, Michiyo; Hattori, Yuya; Sakashita, Tetsuya; Funayama, Tomoo; Yokota, Yuichiro; Ikeda, Hiroko; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 88, 2015/03

Journal Articles

Ion-species dependent bystander mutagenic effect on ${it HPRT}$ locus in normal human fibroblasts induced by C-, Ne- and Ar-ion microbeams

Suzuki, Masao*; Funayama, Tomoo; Yokota, Yuichiro; Muto, Yasuko*; Suzuki, Michiyo; Ikeda, Hiroko; Hattori, Yuya; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 78, 2015/03

We have been studying the radiation-quality dependent bystander cellular effects, such as cell killing, mutation induction and chromosomal damage, using heavy-ion microbeams with different ion species. This year we focused on the ion-species dependent bystander mutagenic effect on ${it HPRT}$ locus in normal human fibroblasts. The confluent culture were irradiated using a 256 (16$$times$$16)-cross-stripe method using C, Ne and Ar microbeam. Gene mutation on ${it HPRT}$ locus was detected with 6-thioguanine resistant clones. The mutation frequency in cells irradiated with C-ion microbeams was 6 times higher than that of non-irradiated control cells and of the sample treated with specific inhibitor of gap-junction cell-to-cell communication. On the other hand, no enhanced mutation frequencies were observed in cells irradiated with either Ne- or Ar-ion microbeams. There is clear evidence that the bystander mutagenic effect via gap-junction communication depends on radiation quality.

Journal Articles

Radiation-quality-dependent bystander effects induced by the microbeams with different radiation sources

Suzuki, Masao*; Autsavapromporn, N.*; Usami, Noriko*; Funayama, Tomoo; Plante, I.*; Yokota, Yuichiro; Muto, Yasuko*; Suzuki, Michiyo; Ikeda, Hiroko; Hattori, Yuya; et al.

Journal of Radiation Research, 55(Suppl.1), P. i54, 2014/03

Journal Articles

Modeling of the pharyngeal muscle in $textit{Caenorhabditis elegans}$ based on FitzHugh-Nagumo equations

Hattori, Yuya; Suzuki, Michiyo; Soh, Zu*; Kobayashi, Yasuhiko; Tsuji, Toshio*

Artificial Life and Robotics, 17(2), p.173 - 179, 2012/12

Journal Articles

Theoretical and evolutionary parameter tuning of neural oscillators with a double-chain structure for generating rhythmic signals

Hattori, Yuya; Suzuki, Michiyo; Soh, Zu*; Kobayashi, Yasuhiko; Tsuji, Toshio*

Neural Computation, 24(3), p.635 - 675, 2012/03

 Times Cited Count:6 Percentile:36.43(Computer Science, Artificial Intelligence)

Journal Articles

An Electrophysiological model of the pharyngeal muscle in $textit{Caenorhabditis elegans}$

Hattori, Yuya; Suzuki, Michiyo; So, Zu*; Kobayashi, Yasuhiko; Tsuji, Toshio*

Proceedings of 17th International Symposium on Artificial Life and Robotics (AROB 2012) (CD-ROM), p.690 - 695, 2012/01

Journal Articles

A Novel tuning method for neural oscillators with a ladder-like structure based on oscillation analysis

Hattori, Yuya; Suzuki, Michiyo; Soh, Zu*; Kobayashi, Yasuhiko; Tsuji, Toshio*

Lecture Notes in Computer Science 6352, p.401 - 410, 2010/09

Oral presentation

The Video-based quantitative evaluation of IR-induced effects on locomotory behavior in ${it Caenorhabditis elegans}$

Suzuki, Michiyo; Sakashita, Tetsuya; Hattori, Yuya; Yanase, Sumino*; Kikuchi, Masahiro; Funayama, Tomoo; Yokota, Yuichiro; Tsuji, Toshio*; Kobayashi, Yasuhiko

no journal, , 

We reported an IR-induced reduction of locomotory rate of ${it Caenorhabditis elegans}$ in the absence of food. In the previous experiments, wild-type animals were irradiated with $$gamma$$-rays in the whole body, and measured the motility using "body bends" (the number of bends in the anterior body region at 20-s intervals). However, the IR-induced effects in the central and posterior body region were not evaluated by the body bends. In the present study, to investigate the IR-induced effects in more detail, we propose a novel method to evaluate the motility of the whole body using the video-based analysis.

Oral presentation

A Novel tuning method for neural oscillators with a ladder structure based on oscillation analysis

Hattori, Yuya; Soh, Zu*; Suzuki, Michiyo; Sakashita, Tetsuya; Kobayashi, Yasuhiko; Tsuji, Toshio*

no journal, , 

no abstracts in English

Oral presentation

Quantitative evaluation of IR-induced effects on locomotory behavior in ${it C. elegans}$

Suzuki, Michiyo; Hattori, Yuya; Sakashita, Tetsuya; Kikuchi, Masahiro; Funayama, Tomoo; Yokota, Yuichiro; Tsuji, Toshio*; Kobayashi, Yasuhiko

no journal, , 

We examined the effects of ionizing radiation (IR) on locomotory behavior using ${it C. elegans}$, and reported an IR-induced reduction of locomotory rate in the absence of food. In the previous experiments, wild-type animals were irradiated with $$gamma$$-rays in the whole body, and measured the motility using "body bends" (the number of bends in the anterior body region at 20-s intervals). However, the IR-induced effects in the central and posterior body region were not evaluated by the body bends. Therefore, we propose a novel method evaluating the motility of whole body by using the video-based analysis. Animals were irradiated with graded doses of $$^{60}$$Co $$gamma$$-rays. Immediately after irradiation, we video-recorded the animals, and analyzed the trajectories and bends at 17 points of the body. The proposed method provides some novel insight about the IR-induced changes on ${it C. elegans}$'s locomotion.

Oral presentation

Effects of $$gamma$$-ray irradiation on locomotory behavior and mechanosensation in ${it Caenorhabditis elegans}$

Suzuki, Michiyo; Sakashita, Tetsuya; Kikuchi, Masahiro; Funayama, Tomoo; Yokota, Yuichiro; Hattori, Yuya; Kobayashi, Yasuhiko

no journal, , 

Oral presentation

Effects of ionizing radiation on pharyngeal pumping in $textit{Caenorhabditis elegans}$

Suzuki, Michiyo; Sakashita, Tetsuya; Hattori, Yuya; Tsuji, Toshio*; Kobayashi, Yasuhiko

no journal, , 

Oral presentation

Effects of ionizing radiation on pharyngeal pumping in $textit{C. elegans}$ and its time course

Suzuki, Michiyo; Sakashita, Tetsuya; Hattori, Yuya; Tsuji, Toshio*; Kobayashi, Yasuhiko

no journal, , 

no abstracts in English

Oral presentation

Modeling and dynamics simulation for the nematode ${it C. elegans}$

Soh, Zu*; Yamada, Yasutaka*; Masaoka, Kazuya*; Hattori, Yuya; Suzuki, Michiyo; Tsuji, Toshio*; Otake, Hisao*

no journal, , 

no abstracts in English

Oral presentation

Effects of ionizing radiation on pharyngeal pumping in ${it Caenorhabditis elegans}$

Suzuki, Michiyo; Sakashita, Tetsuya; Hattori, Yuya; Tsuji, Toshio*; Kobayashi, Yasuhiko

no journal, , 

66 (Records 1-20 displayed on this page)