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Journal Articles

The Role of nitric oxide in radiation-induced bystander cell-killing effect

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

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 67, 2016/02

The role of nitric oxide (NO) in bystander effect was investigated. Human fibroblasts were irradiated with $$gamma$$-rays (LET: 0.2 keV/$$mu$$m) or carbon-ion beam (108 keV/$$mu$$m), and then, co-cultured with the non-irradiated cells. After 24 h culture, the survival rates of non-irradiated cells and the concentrations of nitrate, an oxide of NO, in the medium were measured. The survival rates of non-irradiated cells decreased in dose-dependent and radiation quality-independent manners. Negative relationships between survival rates and nitrite concentrations existed, indicating the amounts of produced NO are an important determinant of bystander effects. Next, a reagent producing two molecules of NO in a half-life of 100 min was added in the culture medium. After incubation of 24 h the survival rates of treated cells did not decrease, suggesting NO produced intracellularly has an important role to lead the bystander effect but is not the signal molecule for intercellular communication.

Journal Articles

Relaxation time of radiation-induced radicals in $$gamma$$-ray irradiated amino acids

Nagata, Natsuki*; Komoda, Seiichi*; Kikuchi, Masahiro; Nakamura, Hideo*; Kobayashi, Yasuhiko; Ukai, Mitsuko*

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 103, 2016/02

no abstracts in English

Journal Articles

Characteristics of radiation-induced bystander effect; Participation of nitric oxide

Yokota, Yuichiro; Funayama, Tomoo; Ikeda, Hiroko; Kobayashi, Yasuhiko

Isotope News, (741), p.21 - 25, 2016/01

Our article published on the International Journal of Radiation Biology (2015) was reviewed. We investigated the dependence of the bystander cell-killing effect on radiation dose and quality, and related molecular mechanisms. Human fibroblasts were irradiated with $$gamma$$-rays or carbon ions and co-cultured with non-irradiated cells. Survival rates of non-irradiated cells decreased and nitrite concentrations in co-culture medium increased with dose. Their dose responses were similar between $$gamma$$-rays and carbon ions. Treatment of the specific nitric oxide (NO) radical scavenger prevented reductions in survival rates of non-irradiated cells. Negative relationships were observed between survival rates and nitrite concentrations. From these results, it was concluded that the bystander cell-killing effect mediated by NO radicals depends on irradiation doses, but not on radiation quality. NO radical production appears to be an important determinant of bystander effects.

Journal Articles

2016 Professional Engineer (PE) test preparation course "Nuclear and Radiation Technical Disciplines"

Takahashi, Naoki; Yoshinaka, Kazuyuki; Harada, Akio; Yamanaka, Atsushi; Ueno, Takashi; Kurihara, Ryoichi; Suzuki, Soju; Takamatsu, Misao; Maeda, Shigetaka; Iseki, Atsushi; et al.

Nippon Genshiryoku Gakkai Homu Peji (Internet), 64 Pages, 2016/00

no abstracts in English

Journal Articles

Study on detection method for 8-hydroxyguanine induced in bovine livers by $$gamma$$-irradiation

Kikuchi, Masahiro; Kobayashi, Yasuhiko

Shokuhin Shosha, 50(1), p.3 - 8, 2015/10

no abstracts in English

Journal Articles

ESR signal changes recorded in $$gamma$$-irradiated bovine livers

Kikuchi, Masahiro; Kobayashi, Yasuhiko

Shokuhin Shosha, 50(1), p.9 - 12, 2015/10

no abstracts in English

Journal Articles

Peak-fitting analysis with Gaussian line shapes against experimental ESR spectrum consisting of multiple peak

Kikuchi, Masahiro; Nagata, Natsuki*; Komoda, Seiichi*; Kameya, Hiromi*; Ukai, Mitsuko*; Kobayashi, Yasuhiko

Shokuhin Shosha, 50(1), p.13 - 19, 2015/10

no abstracts in English

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:3 Percentile:53.75(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

Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

Tomita, Masanori*; Matsumoto, Hideki*; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke*; Maeda, Munetoshi*; Kobayashi, Yasuhiko

Life Sciences in Space Research, 6, p.36 - 43, 2015/07

A radiation-induced bystander response is generally known as a cellular response induced in unirradiated cell by receiving bystander signaling factors released from directly irradiated cells of a cell population. Bystander responses induced by high-LET heavy ions at low fluence are an important problem concerning the health of astronauts in the space environment. Here we set out NO-mediated bystander signal transductions induced by high-LET heavy-ion microbeam irradiation in normal human fibroblasts. Our findings suggest that Akt- and NF-$$kappa$$B-dependent signaling pathway involving COX-2 plays an important role in the NO-mediated high-LET heavy-ion-induced bystander responses. Additionally, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells, which are distinguish form directly irradiated cells.

Journal Articles

What are the essential characteristics of the radiation "action"

Kobayashi, Yasuhiko

Kankyo To Kenko, 28(2), p.129 - 139, 2015/06

no abstracts in English

Journal Articles

The Bystander cell-killing effect mediated by nitric oxide in normal human fibroblasts varies with irradiation dose but not with radiation quality

Yokota, Yuichiro; Funayama, Tomoo; Muto, Yasuko*; Ikeda, Hiroko; Kobayashi, Yasuhiko

International Journal of Radiation Biology, 91(5), p.383 - 388, 2015/05

 Times Cited Count:5 Percentile:34.97(Biology)

We investigated the dependence of the bystander cell-killing effect on radiation dose and quality, and related molecular mechanisms. Human fibroblasts were irradiated with $$gamma$$-rays or carbon ions and co-cultured with non-irradiated cells. Survival rates of non-irradiated cells decreased and nitrite concentrations in culture medium increased with increasing doses. Their dose responses were similar between $$gamma$$-rays and carbon ions. Treatment of the specific nitric oxide (NO) radical scavenger prevented reductions in survival rates of non-irradiated cells. Negative relationships were observed between survival rates and nitrite concentrations. From these results, it was concluded that the bystander cell-killing effect mediated by NO radicals in human fibroblasts depends on irradiation doses, but not on radiation quality. NO radical production appears to be an important determinant of $$gamma$$-ray- and carbon-ion-induced bystander effects.

Journal Articles

Principle of radiation sterilization and world trends in food irradiation

Kobayashi, Yasuhiko

Sofuto, Dorinku Gijutsu Shiryo, (175), p.103 - 128, 2015/04

Food irradiation is a technology to treat foods with ionizing radiation such as $$gamma$$-rays and electron beams to improve the safety and extends the shelf life of foods by reducing or eliminating microorganisms and insects, and by prevention of sprouting. The food irradiated with ionizing radiation is named as "irradiated food". Many international organizations have approved the safety and usefulness of food irradiation. Ionizing radiation can treat packaged foods and fresh and/or frozen products, and effectively and uniformly treat all portions of foods. Food irradiation is an environmentally friendly technology without usage of chemicals and contributes to the solution of food security and food sanitary problems especially reducing post-harvest losses of foods and controlling food borne illness, as an alternative to chemical fumigation with ethylene oxide and methyl bromide gasses. Japan has a 50 years history of food irradiation research. The "Japanese Research Association for Food Irradiation" has been launched in 1965. It was legally authorized to irradiate potatoes for preventing germination in 1972 and since 1974 irradiation potato has been shipped from the Shihoro-cho Agricultural Cooperative Association in Hokkaido. Recently commercial food irradiation has increased significantly in Asia, however, Japan is now far behind other countries and it is called a "food irradiation underdeveloped country".

Journal Articles

Dose responses of irradiated fresh papaya recorded on ESR at different temperature

Kikuchi, Masahiro; Ukai, Mitsuko*; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 89, 2015/03

Journal Articles

Analysis of radicals induced in irradiated amino acid using Pulse-ESR

Kishida, Keigo*; Kikuchi, Masahiro; Nakamura, Hideo*; Kobayashi, Yasuhiko; Ukai, Mitsuko*

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 90, 2015/03

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

Effect of ionizing radiation upon dehydrated Pv11 cultured cells originated from the sleeping chironomid

Watanabe, Kazuyo*; Akitsuki, Takashi*; Shimura, Sachiko*; Gusev, O.*; Cornette, R.*; Kikawada, Takahiro*; Sakashita, Tetsuya; Funayama, Tomoo; Kobayashi, Yasuhiko; Okuda, Takashi*

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 87, 2015/03

The Sleeping Chironomid, ${it Polypedilum vanderplanki}$ can stand complete desiccation (anhydrobiosis) and also shows radio-resistance. Recently, we have generated cultured cell (Pv11) originated from ${it P. vanderplanki}$ embryo which can also stand complete dehydration. In this study, we examine the tolerance of cultured cell Pv11 against ionbeam irradiation.

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

Bystander effect mediated by nitric oxide depends on irradiation dose but not on radiation quality

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

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 75, 2015/03

We investigated the bystander effect induced by $$gamma$$-rays or carbon ions and analyzed the role of nitric oxide (NO) in the effect. Normal human fibroblasts were used. Cells inoculated on a porous membrane were irradiated with varying doses of $$gamma$$-rays or carbon ions. Irradiated cells were then non-contact co-cultured with non-irradiated cells for 24 h. After co-culture, the survival rates of non-irradiated bystander cells co-cultured with irradiated cells decreased with increasing dose and bottomed out at 0.5 Gy or higher doses. This indicates that the bystander effect is dependent on irradiation dose but independent of radiation quality. Next, a specific NO scavenger c-PTIO was added to the culture medium during irradiation and co-culture. This treatment prevented the reduction in survival rates of bystander cells, clearly indicating that NO has an important role in the bystander effect.

Journal Articles

Target irradiation of individual cells using focusing heavy-ion microbeam of JAEA-Takasaki, 5; Irradiation of individual cells with scanned heavy-ion microbeam

Funayama, Tomoo; Yokota, Yuichiro; Suzuki, Michiyo; Sakashita, Tetsuya; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 73, 2015/03

Using a collimating heavy-ion microbeam system, we have explored various effects of heavy-ion hit on biological materials. However, there are limitations of the collimating system in the size of the microbeam spot and in the irradiation speed that cannot be overcome in principle. Thus, we started the development of a focusing microbeam system for target-irradiating individual cells more precisely. In this year, we established the protocol for irradiating "actual" cell sample with scanned beam. In the experiment, the HeLa cells were inoculated on a CR-39 film, then place on the sample stage. The microscopic image of cells was analyzed, and the cells were irradiated with scanned neon microbeam. After irradiation, we found the correspondence of the distribution pattern of the ion hit positions and the $$gamma$$-H2AX foci on cell nuclei, indicating rapid and accurate irradiation of individual cells with the focusing heavy-ion microbeam.

Journal Articles

Mechanisms for the induction of radioadaptive response by radiation-induced bystander response

Matsumoto, Hideki*; Tomita, Masanori*; Otsuka, Kensuke*; Hatashita, Masanori*; Maeda, Munetoshi*; Funayama, Tomoo; Yokota, Yuichiro; Suzuki, Michiyo; Sakashita, Tetsuya; Ikeda, Hiroko; et al.

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 76, 2015/03

The objective of this project is to elucidate molecular mechanisms for the induction of radioadaptive response through radiation-induced bystander responses induced by irradiation with heavy ion microbeams in JAEA. We found that the adaptive response was induced by Ar (520 MeV $$^{40}$$Ar$$^{14+}$$) microbeam-irradiation of a limited number of cells, followed by the broad beam-irradiation and that the adaptive response was almost completely suppressed by the addition of carboxy-PTIO, as a nitric oxide (NO) scavenger. In addition, we found several genes induced specifically and preferentially when radioadaptive response could be induced. We confirmed that ${it iNOS}$ expression was specifically induced only when radioadaptive response could be induced. Our findings strongly suggested that radioadaptive response can be induced by NO-mediated bystander responses evoked by irradiation with heavy ion microbeams.

614 (Records 1-20 displayed on this page)