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People living in high background radiation areas (HBRAs) possibly develop the radioadaptive response (RAR) phenomenon. The Mamuju area in West Sulawesi Indonesia is known as an HBRA in Indonesia due to its high natural uranium contents. It is possible that RAR has developed in Mamuju inhabitants. To prove this hypothesis, here in this study, evaluation of the individual radiosensitivity in the inhabitants of Takandeang Village, Mamuju, was conducted using G 2 micronucleus (MN) assay. Association between blood groups and TP53 Arg72Pro polymorphism with individual radiosensitivity was also evaluated in this study. Using G 2 MN assay, we assessed the individual radiosensitivity of Takandeang Village inhabitants and control samples. For each sample, three parameters were calculated. The spontaneous (baseline) MN number, MN number after 0.5 Gy in vitro irradiation, and radiation-induced MN were calculated to predict the individual radiosensitivity. The radiation-induced MN was defined by subtracting the spontaneous MN number from the MN number after irradiation. The mean and SD of the number of micronuclei induced by radiation found in control group (CG) was set as the cutoff value to determine the individual radiosensitivity in all samples. The occurrence of a radiation-induced MN value higher than the mean CG + 1SD CG was scored as 1, indicating a milder radiosensitive phenotype, whereas a result higher than the mean CG + 2SD CG was scored as 2, and indicated a more severe radiosensitive phenotype. When the individual value was lower than the mean CG + 1SD CG, a score of 0 was attributed to the tested subject. The results showed that four individuals in Takandeang Village inhabitants had a milder radiosensitive phenotype, while the others were categorized as normal radiosensitive. A similar finding was also found in control samples. Our study failed to find any correlation between radiosensitivity and either blood group or the TP53 Arg72Pro polymorphism. Overall, our study revealed the possibility of RAR phenomena in Takandeang Village inhabitants. Further investigation using a different point of radiation dose value and larger sample number should be performed to validate this study results.Journal homepage: http://aij.batan.go.id

Surniyantoro HNE, Lusiyanti Y, Rahardjo T, Nurhayati S, Tetriana D. 2018. Association between XRCC1 exon 10(Arg399Gln) gene polymorphism and micronucleus as a predictor of DNA damage among radiation workers. Biodiversitas 19: 1676-1682. This study was aimed to examine the association between XRCC1 exon 10 gene polymorphism and micronucleus frequencies inradiation workers and their relation to the confounding factors. This study involved 37 radiation workers and 37 controls from severalhospitals in Indonesia. Genotyping of X-ray cross-complementing group 1 (XRCC1) exon 10 gene polymorphism and micronucleusassay were performed using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) and Cytokinesis-Block Micronucleus assay (CBMN assay), respectively. The results indicated that MN frequencies were not significantly higher in theexposed workers than in controls (20.46±6.42 versus 16.89 ±9.72; P=0.07). The micronucleus frequencies of radiation workers withmutant genotype showed not significantly higher than controls in the same genotypes (22±6.64 versus 11.75 ± 8.13; P=0.11). Theconfounding factors, like age, years of employment and equivalent doses were significantly associated with micronucleus frequencies(P<0.05). The equivalent dose has a significantly positive correlation with micronucleus frequencies among radiation workers,increasing the MN frequencies by 16.3 per 1 mSv of equivalent dose (P=0.001). The genetic polymorphism of XRCC1 gene exon 10demonstrated no association with the extent of DNA damage in the hospital radiation workers. The MN frequencies were stronglyassociated with age, equivalent dose and years of employment.

Abstract. Surniyantoro HNE, Darlina, Nurhayati S, Tetriana D, Syaifudin M. 2016. Gamma ray irradiation inhibits Plasmodium falciparum multiplication in in vitro culture supplemented with tritium labeled hypoxanthine. Nusantara Bioscience 8: 8-13. Malaria remains a major public health threat in the world. Therefore an attempt to create malaria vaccine for supporting the control of disease was taken by attenuating parasites with gamma rays and it was proven effective based on microscopic observation. Objective of this research was to assess the effectiveness of gamma rays to attenuate malaria parasites based on isotopic method. A laboratory strain of P. falciparum (3D7) was in vitro cultured with standard procedure and it was irradiated with gamma rays at doses of 150-250 Gy and unirradiated parasites served as control. Twenty four hours after 1-2 µCi of 3 H-hypoxanthine was added into culture 100 µl of medium was taken and was repeated at various times, then hypoxanthine incorporation was measured with beta counter. Microscopic observation of parasitemia in culture was also done. The results showed that there was a fluctuation in multiplication of parasites post irradiation mainly in higher dose (more than150 Gy). Irradiated of parasites were more active in incorporate with purine precursor up to 48 hours. Parasites returned to their highest activity at 116 hours after hypoxanthine addition. No significant difference was found among doses of irradiation with p of 0.05. This was quite different with the finding from microscopic observation. It was known that dose of 150 Gy was the most effective dose for inhibiting of the parasite multiplication where some factors affecting these facts.

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