Observation of morphological abnormalities in silkworm pupae after feeding CsCl-supplemented diet to evaluate the effects of low dose-rate exposure.

Since the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, morphological abnormalities in lepidopteran insects, such as shrinkage and/or aberration of wings, have been reported. Butterflies experimentally exposed to radiocesium also show such abnormalities. However, because of a lack of data on absorbed dose and dose-effect relationship, it is unclear whether these abnormalities are caused directly by radiation.

The combined effect of neutron irradiation and temozolomide on glioblastoma cell lines with different MGMT and P53 status.

Temozolomide (TMZ) is a DNA-alkylating agent used for chemo-radiotherapy of glioblastoma, which is also a target cancer for boron neutron capture therapy (BNCT). Although the DNA-repair enzyme O-methylguanine DNA methyltransferase (MGMT) and the tumor suppressor p53 are mutated in some glioblastoma cells, it remains unknown whether these mutations affect sensitivity to neutron irradiation. We examined sensitivity to neutron irradiation and TMZ in two glioblastoma cell lines: T98G, which is p53-mutant with high levels of MGMT activity; and A172, which is p53-wild-type and has low MGMT activity.

DNA Double-strand Breaks Induced byFractionated Neutron Beam Irradiation for Boron Neutron Capture Therapy.

Aim: To use the 53BP1 foci assay to detect DNA double-strand breaks induced by fractionated neutron beam irradiation of normal cells.

Materials And Methods: The Kyoto University Research Reactor heavy-water facility and gamma-ray irradiation system were used as experimental radiation sources. After fixation of Chinese Hamster Ovary cells with 3.

Radioactive contamination of arthropods from different trophic levels in hilly and mountainous areas after the Fukushima Daiichi nuclear power plant accident.

In order to understand the influence of the Fukushima Daiichi nuclear power plant accident on the ecosystem in hilly and mountainous areas of Fukushima Prefecture, chronological changes in the levels of radiocesium in arthropod species were investigated. From 2012 to 2014, arthropods from different trophic levels were sampled and the air radiation dose rates at the sampling sites were analyzed. The air radiation dose rates showed a significant and constant reduction over the 2 years at the sampling sites in Fukushima.

Influence of p53 status on the effects of boron neutron capture therapy in glioblastoma.

Background/aim: The tumor suppressor gene p53 is mutated in glioblastoma. We studied the relationship between the p53 gene and the biological effects of boron neutron capture therapy (BNCT).

Materials And Methods: The human glioblastoma cells; A172, expressing wild-type p53, and T98G, with mutant p53, were irradiated by the Kyoto University Research Reactor (KUR).

Optimised mounting conditions for poly (ether sulfone) in radiation detection.

Poly (ether sulfone) (PES) is a candidate for use as a scintillation material in radiation detection. Its characteristics, such as its emission spectrum and its effective refractive index (based on the emission spectrum), directly affect the propagation of light generated to external photodetectors. It is also important to examine the presence of background radiation sources in manufactured PES.

Poly (ether sulfone) as a scintillation material for radiation detection.

Considerable attention has been drawn to the advantages of using aromatic ring polymers for scintillation materials in radiation detection. Thus, it is important to identify and characterise those with the best potential. Here, we characterise poly (ether sulfone) (PES), which is an amber-coloured transparent resin that possesses sulfur as a main component and has a density of 1.

Dose-rate effect was observed in T98G glioma cells following BNCT.

Background: It is generally said that low LET radiation produce high dose-rate effect, on the other hand, no significant dose rate effect is observed in high LET radiation. Although high LET radiations are produced in BNCT, little is known about dose-rate effect of BNCT.

Materials And Methods: T98G cells, which were tumor cells, were irradiated by neutron mixed beam with BPA.

Mechanism of wavelength conversion in polystyrene doped with benzoxanthene: emergence of a complex.

Fluorescent guest molecules doped in polymers have been used to convert ultraviolet light into visible light for applications ranging from optical fibres to filters for the cultivation of plants. The wavelength conversion process involves the absorption of light at short wavelengths followed by fluorescence emission at a longer wavelength. However, a precise understanding of the light conversion remains unclear.

Optimized mounting of a polyethylene naphthalate scintillation material in a radiation detector.

Polyethylene naphthalate (PEN) has great potential as a scintillation material for radiation detection. Here the optimum mounting conditions to maximize the light collection efficiency from PEN in a radiation detector are discussed. To this end, we have determined light yields emitted from irradiated PEN for various optical couplings between the substrate and the photodetector, and for various substrate surface treatments.

Induced radioactivity in the blood of cancer patients following Boron Neutron Capture Therapy.

Since 1990, Boron Neutron Capture Therapy (BNCT) has been used for over 400 cancer patients at the Kyoto University Research Reactor Institute (KURRI). After BNCT, the patients are radioactive and their (24)Na and (38)Cl levels can be detected via a Na-I scintillation counter. This activity is predominantly due to (24)Na, which has a half-life of 14.

Relative biological effects of neutron mixed-beam irradiation for boron neutron capture therapy on cell survival and DNA double-strand breaks in cultured mammalian cells.

Understanding the biological effects of neutron mixed-beam irradiation used for boron neutron capture therapy (BNCT) is important in order to improve the efficacy of the therapy and to reduce side effects. In the present study, cell viability and DNA double-strand breaks (DNA-DSBs) were examined in Chinese hamster ovary cells (CHO-K1) and their radiosensitive mutant cells (xrs5, Ku80-deficient), following neutron mixed-beam irradiation for BNCT. Cell viability was significantly impaired in the neutron irradiation groups compared to the reference gamma-ray irradiation group.

DNA double-strand break induction in Ku80-deficient CHO cells following boron neutron capture reaction.

Background: Boron neutron capture reaction (BNCR) is based on irradiation of tumors after accumulation of boron compound. 10B captures neutrons and produces an alpha (4He) particle and a recoiled lithium nucleus (7Li). These particles have the characteristics of high linear energy transfer (LET) radiation and have marked biological effects.

Ascorbic acid 2-glucocide reduces micronucleus induction in distant splenic T lymphocytes following head irradiation.

Purpose: Evidence from in vivo studies suggests there are enhanced radiation effects in abscopal regions after local head gamma ray irradiation. Splenocyte apoptosis and T lymphocyte micronuclei were induced at higher rates than what would be estimated given the dose at a shielded, distant position. In addition, we evaluated the radio-protective effects of ascorbic acid, acting as a radical scavenger on enhanced radiation effects in the shielded spleen following local head irradiation.

Expression of brain-type fatty acid-binding protein (fabp7) in medaka during development.

Fatty acid-binding proteins (FABPs) belong to a multigene family of small intracellular proteins that bind hydrophobic ligands. Recent studies have indicated that FABP7 plays important roles in neurogenesis or neuronal migration in vertebrates. In this study, we isolated cDNA and the genomic fragment containing the fabp7 gene for medaka fish and examined the expression of the medaka fabp7 gene through the development of their central nervous system (CNS).

Ionizing radiation downregulates ASPM, a gene responsible for microcephaly in humans.

Microcephaly is a malformation associated with in utero exposed atomic bomb survivors and can be induced in mice by fetal exposure to ionizing radiation (IR). The pathogenesis of IR-induced microcephaly, however, has not been fully understood. Our analyses of high-coverage expression profiling (HiCEP) demonstrated that the abnormal spindle-like microcephaly associated gene (ASPM) was down-regulated in irradiated human diploid fibroblasts.

Impact of gamma irradiation on the transformation efficiency for extracellular plasmid DNA.

Extracellular DNA is omnipresent in aquatic environments and is thought to be a genetic material for horizontal gene transformation between microorganisms. We studied the impact of gamma irradiation on the transformation efficiency (transformants number per ng of DNA per ml) of extracellular DNA. Plasmid pEGFP as a model extracellular DNA was irradiated by gamma rays.

A bystander effect observed in boron neutron capture therapy: a study of the induction of mutations in the HPRT locus.

Purpose: To investigate bystander mutagenic effects induced by alpha-particles during boron neutron capture therapy, we mixed cells that were electroporated with borocaptate sodium (BSH), which led to the accumulation of (10)B inside the cells, and cells that did not contain the boron compound. The BSH-containing cells were irradiated with alpha-particles produced by the 10B(n,alpha)7Li reaction, whereas cells without boron were affected only by the 1H(n,gamma)2H and 14N(n,rho)14C reactions.

Methods And Materials: The lethality and mutagenicity measured by the frequency of mutations induced in the hypoxanthine-guanine phosphoribosyltransferase locus were examined in Chinese hamster ovary cells irradiated with neutrons (Kyoto University Research Reactor: 5 MW).

Mcl-1 depletion in apoptosis elicited by ionizing radiation in peritoneal resident macrophages of C3H mice.

Remarkably, apoptosis was induced by exposing peritoneal resident macrophages (PRM) of C3H mice, but not other strains of mice, to ionizing radiation. The molecular mechanism of this strain-specific apoptosis in PRM was studied. The apoptosis elicited in C3H mouse PRM 4 h after exposure was effectively blocked by proteasome inhibitors.

Repair of DNA damage induced by accelerated heavy ions in mammalian cells proficient and deficient in the non-homologous end-joining pathway.

Human and rodent cells proficient and deficient in non-homologous end joining (NHEJ) were irradiated with X rays, 70 keV/microm carbon ions, and 200 keV/microm iron ions, and the biological effects on these cells were compared. For wild-type CHO and normal human fibroblast (HFL III) cells, exposure to iron ions yielded the lowest cell survival, followed by carbon ions and then X rays. NHEJ-deficient xrs6 (a Ku80 mutant of CHO) and 180BR human fibroblast (DNA ligase IV mutant) cells showed similar cell survival for X and carbon-ion irradiation (RBE = approximately 1.

Extremely low dose ionizing radiation up-regulates CXC chemokines in normal human fibroblasts.

Although the public today could be exposed to X-rays as high as 1 cGy due to diagnostic procedures, the biological effects of this low-dose range have not been well established. We searched through >23,000 transcripts in normal human fibroblasts, HFLIII, using a novel comprehensive expression analysis method. More than 200 genes were up-regulated transiently by 1 cGy of X-rays during the 1-hour period after irradiation.

Radio-sensitivity of the cells from amyotrophic lateral sclerosis model mice transfected with human mutant SOD1.

In order to clarify the possible involvement of oxidative damage induced by ionizing radiation in the onset and/or progression of familial amyotrophic lateral sclerosis (ALS), we studied radio-sensitivity in primary cells derived from ALS model mice expressing human mutant SOD1. The primary mouse cells expressed both mouse and the mutant human SOD1. The cell survival of the transgenic mice (with mutant SOD1), determined by counting cell numbers at a scheduled time after X-irradiation, is very similar to that of cells from wild type animals.

Hypoxia-ischemic insult in neonatal rats induced slowly progressive brain damage related to memory impairment.

The present study was designed to determine potential associations between the brain damage induced by hypoxic-ischemic (HI) insult and spatial learning impairment in an eight-arm radial maze task. We first determined the pathological outcomes after 2, 5, 9, and 17 weeks of recovery following the HI insult. The results show that the brain damage progressed from 2 up to 17 weeks of recovery.

Ectopic neurons in the hippocampus may be a cause of learning disability after prenatal exposure to X-rays in rats.

The relationship between an impairment of spatial navigation and an incidence of ectopic neurons in the dorsal hippocampus was investigated in adult rats that were prenatally exposed to X-ray irradiation. Adult rats which had received 1.5 Gy X-rays at embryonic day 15 (E15) showed significant learning disability in the water-maze task.