[en] KAERI and INP(Poland) have been carried out parallel study and joint experiments on the major topics according to MOU about their cooperative project. The experimental materials were T-4430 clones. Main results of the cooperative project were made on ^response of TSH mutation to low LET radiation, response of TSH mutation to neutrons, response of TSH to mixed irradiation with different radiations and synergism between radiation and environmental factors such as photo period and diurnal temperature difference. Both institutes have established wide variety of research techniques applicable to tradescantia study through the cooperation. These result of research can make the role of fundamental basis for the better relationship between Korea and Poland. (author). 46 refs., 11 tabs., 31 figs

[en] This study deals with the biological effects of black mouse (C57BL) irradiated with neutron irradiation by using Boron Neutron Capture Therapy facility in HANARO reactor. These include mortality, body wt., hair color, testis volume, sperm count and immune cell populations in mouse spleen after 80 days later by thermal neutron irradiation. Six week old C57BL male mice were irradiated with neutron irradiation for 1 hr or 2 hrs (flux : 1.036739E +09). These irradiat ion doses estimated 15Gy and 30Gy, respectively. Survival days and hair color in mice was checked. On day 80 after irradiation, testis were taken for volume and sperm count. Also spleen was taken for FACS and spleen cells were isolatd and discarded RBC by treating with lysising solution. These cells were placed on ice and immunofluorescence staining was performed. Phycoerythrin (PE )-anti-CD3e, fluorescein isothiocyanate (FITC)-anti-CD4, and FITC-anti-CD8 were added, then the immunostaining cells were incubated on ice for 40 min. The resulting cells were washed with a PBS buffer 3 times and analyzed using a Flow cytometer. All experimental animals survived over 90 days but in case of 30 Gy neutron irradiation, black mice hair were changed white color on the center of the back. Neutron irradiation of black mice show similar in damage of spleen immune cells by subpopulation of T helper and T cytotoxic cells compared to the control non - irradiated group. These results show that treatment of neutron irradiation without boron compounds for 2 hrs in mice can survive over 90 days with hair color change from black to white. Damaged spleen cells recover after long time by irradiation but testis volume and no. of sperm are not recover compared to the normal group in response to neutron irradiation

[en] So as to establish the biological effects of BNCT in the HANARO Reactor, biological damages in cells and animals with treatment of boron/neutron were investigated. And 124I-BPA animal PET image, analysis technology of the boron contents in the mouse tissues by ICP-AES was established. A Standard clinical protocol, a toxicity evaluation report and an efficacy investigation report of BNCT has been developed. Based on these data, the primary permission of clinical application was acquired through IRB of our hospital. Three cases of pre-clinical experiment for boron distribution and two cases of medium-sized animal simulation experiment using cat with verifying for 2 months after BNCT was performed and so the clinical demonstration with a patient was prepared. Also neutron flux, fast neutron flux and gamma ray dose of BNCT facility were calculated and these data will be utilized good informations for clinical trials and further BNCT research. For the new synthesis of a boron compound, o-carboranyl ethylamine, o-carboranylenepiperidine, o-carboranyl-THIQ and o-carboranyl-s-triazine derivatives were synthesized. Among them, boron uptake in the cancer cell of the triazine derivative was about 25 times than that of BPA and so these three synthesized methods of new boron compounds were patented

[en] DNA damage can be assessed by the single cell gel electrophoresis(SCGE), alias, Comet assay; a fast, simple and sensitive technique. Within the last 20 years, the comet assay has been used to investigate primary DNA damage, such as double-strand breaks, single strand breaks, alkali-labile sites, incomplete repair sites and crosslingks. Therefore, comet assay has been applied in a great number of studies to investigate the early biological effects of DNA-damaging agents in environmental, occupational and pathological conditions or exposure to chemicals at the cellular level. From this reason, we investigated the DNA damage in melanoma cells B16F0 treated with boron compounds such as BPA and BSH after neutron irradiation in vitro

[en] Damage levels of plasmid DNAs were observed according to the concentrations of the boron compounds and irradiation doses of a neutron or gamma irradiation. Plasmid used were pBR322 (2870 bp), ψX174 RF (5286 bp) and pTZ19R (4363 bp). DNA damage of plasmid DNA treated with boron compounds after an irradiation was obtained by an agarose gel electrophoresis and observed by a UV illuminator. In the case of a neutron irradiation with boron compounds, DNA damages of the plasmid DNAs were induced according to the high concentrations of the boron compounds and the high irradiation doses. But in the case of a γ-irradiation, the DNA damage was similar when compared to non-irradiated control. Therefore, DNA damage patterns of plasmid DNA by a treatment of boron compounds and a neutron or γ-irradiation were somewhat different showing that the higher the boron concentrations and irradiation doses, the higher the damage of plasmid DNA for a neutron irradiation but no damage for a gamma irradiation in spite of the high boron concentrations and irradiation doses. This result suggest that boron compounds such as BPA and BSH have an important role regarding the damage of plamid DNA by a neutron irradiation, however, not by a gamma irradiation. (author)

[en] Five strains of radiation-resistant gram-positive bacteria were isolated from imported frozen shrimps of South-east Asian countries after irradiated with more than 5 kGy. All strains were able to grow on nutrient agar slants with pink to red color. Cell of 4 strains were diplococci or tetrads, and one strain was rod shaped. The peptide subunit of cells of all strains contained ornithine, and GC content of DNA ranged from 58 to 68%. Many of biochemical characteristics were also resembling in all of isolates. From these results, 4 strains were identified as Deinococcus proteolyticus and the strain N1 was belong to Deinobacter grandis in the family of Deinococaceae. The D₁₀ values in phosphate buffer ranged from 0.6 to 2.0 kGy under aerobic condition, and ranged from 1.2 to 2.4 kGy under anaerobic condition. Distribution of Deinococaceae in frozen shrimps were 10¹ to 10² per gram which is much smaller amount compared with sewage sludges or rice straws. (J.P.N.)

[en] In-phantom gamma-ray dose distribution is measured at the HANARO BNCT irradiation facility. The measurements are performed with TLD-700 dosimeters. The thermal neutron sensitivity of TLD-700 used in this experiment is estimated to be 1.43 rad/¹⁰n/cm². The free gamma-ray dose and inphantom dose distribution are measured at the exit of the beam collimator with variation of liquid nitrogen cooling condition of radiation filter. The free gamma-ray dose rate is measured as 1.8 Gy/hr at the center of beam exit. Measured in-phantom gamma-ray dose has a maximum value at the depth of 2 mm in phantom, and then it decreases rapidly. When the radiation filter is cooled by liquid nitrogen, the maximum gamma-ray dose rate is 14.2 Gy/hr

[en] Despite many developments in neurosurgical and pharmacological techniques, a malignant glioma is one of the most deadly cancers and to date lacks an effective treatment in humans. Boron neutron capture therapy (BNCT) has been regarded as a promising treatment for the malignant gliomas. BNCT is a two step radiotherapy in which a selective radiation effects on tumor cells is achieved by first targeting the tumor with ¹⁰B and then exposing it to low energy neutrons. The stable ¹⁰B isotope has a large cross-sectional area for the capture of thermal neutrons. The reaction yields intensively ionizing particles, ⁴He²⁺ (α particles) and recoiling ⁷Li³⁺ nuclei. These highly cytotoxic nuclear fragments destroyed the tumor cells. For the successful BNCT, high amount boron molecules must be carried into the target tumor cells selectively. Borocaptate sodium (BSH) is a low molecular weight substance originally tested for the BNCT. Clinical trials using BSH for the BNCT of brain tumors reported significant outcomes with long-term survivals in patients with malignant gliomas. Boronated amino acid analogs, p-boronophenylalanine (BPA), are used in the BNCT for the treatment of malignant melanomas. Recently, BPA has been reported to be preferentially taken up by glioma cells. These boron-enriched compounds should be kept low to minimize the damage to normal tissues. Therefore, the preliminary study for the enhancement of selective delivery of boron atoms to tumor cells has been reported. Also, several investigators proposed abilities of boron compounds as a radioprotector against gamma ray-exposed condition. The present study tested the comparative effect of boron compounds and known radioprotectant agents in the gamma-irradiated gliomas

[en] The alkaline single-cell gel or comet assay is a sensitive, reliable, and rapid method for DNA doubleand single-strand breaks, alkali-labile sites and delayed repair site detection, in eukaryotic individual cells. Given its overall characteristics, this method has been widely used over the past few years in the area of genetic toxicology and a number of investigators have used this version to evaluate in vitro and/or in vivo genotoxicity of several chemicals and radiation. From this reason, we evaluated the DNA damage in blood and splenic lymphocytes after neutron and gamma irradiation in C57BL/6 mice pretreated with boron compounds

[en] The development of increased radioresistance of Salmonella typhimurium DO1 by repeated exposure of gamma irradiation was studied after combination treatment of outgrowth of survivors with selective enrichment methods by nutrient broth or glucose-NH₄ broth. Original D₁₀ value on nutrient agar plates was obtained as 0.17 kGy and increased a little after 5 times exposures of gamma irradiation with enrichment by nutrient broth and brilliant green-lactose broth. Subsequent exposure with combination enrichment of brilliant green-lactose broth and selenite-cystine broth developed the radioresistance at higher dose region of survival curves. However, these radioresistance was unstable, and easily go back to original level due to the some condition of enrichment growth and repeated culture incubation. Biochemical characteristics including serological properties were not changed even after 8 times exposure. However, percentages of elongated cells were increased on radioresistant cultures which were developed by repeated exposures. (author)