Sangat Penting, Pemeriksaan Kesehatan Pekerja Radiasi

Penggunaan teknologi nuklir untuk kebutuhan manusia telah berkembang pesat meliputi seluruh lapangan kehidupan. Walaupun jelas sekali manfaat telah dipetik oleh umat manusia dari penggunaan teknologi nuklir, sisi bahaya yang dapat ditimbulkan- nya tidak boleh diabaikan terutama bagi mereka yang karena tugasnya langsung berhadapan dengan bahaya ini. Masalahnya adalah menjaga agar dalam menggunakan teknologi nuklir yang melibatkan penggunaan radiasi pengion, dosis radiasi yang diterima oleh pekerja radiasi harus selalu berada dalam batas-batas yang diijinkan, sehingga risiko yang diterima baik oleh pekerja radiasi maupun oleh penduduk secara keseluruhan tidak berlebihan. Ketentuan Keselamatan Radiasi tertuang dalam Penjelasan Peraturan Pemerintah (PP) Nomor 63 tahun 2000 mengenai ”Keselamatan dan Kesehatan Terhadap Pemanfaatan Radiasi Pengion”. Secara umum PP ini dimaksudkan sebagai pelaksanaan Undang-undang Nomor 10 Tahun 1997 tentang Ketenaganukliran. Didalamnya diatur tidak saja keselamatan kerja, tetapi juga keselamatan masyarakat dan lingkungan hidup serta tanggung jawab dan kewenangan Badan Pengawas, penguasa instalasi, petugas proteksi radiasi, serta pekerja radiasi dalam pemanfaatan tenaga nuklir sesuai dengan pola kerja yang selalu melaksanakan budaya keselamatan (safety culture), sehingga jelas siapa yang bertanggung jawab apabila terjadi sesuatu yang tidak diinginkan dalam pemanfaatan tersebut. Sasaran PP adalah terwujudnya situasi agar setiap pemanfaatan tenaga nuklir berwawasan keselamatan dan lingkungan

The Feasibility of Gamma Irradiation for Developing Malaria Vaccine

Malaria, a plasmodial disease, causes more than one million deaths per year and has a significant public health impact. Improved access to prompt treatment with effective antimalarial drugs need to be conducted for prevention of infection in high risk groups. However, the parasite as causal agent has exhibited a potential danger of wide-spread resistances. This warning has directed attention to the study of alternative methods of protection against the disease, among them is to do the immunization. A deeper understanding of the nature and regulation of protective immune mechanisms against this parasite will facilitate the development of much needed vaccines. Developing a malaria vaccine remains an enormous scientific, technical, and financial challenge. Currently a vaccine is not fully available. Among the practical applications of radiobiological techniques that may be of considerable interest for public health is the use of ionizing radiation in the preparation of vaccines. Convincing data were reported that sporozoites of Plasmodium berghei irradiated with X- or gamma-rays, provide an antigenic stimulus effective to induce a protective immune response in mice and rats against subsequent sporozoite infection. Irradiated parasites are better immunogens than killed ones and although non-infective they are still metabolically active, as shown by continued protein and nucleic acid synthesis. There is a substantial number of data from human studies demonstrating that sporozoites attenuated by radiation are potent inducers of protective immunity and that they are safe and do not give rise to the asexual erythrocytic infections that cause malaria. This vaccine is relatively inexpensive to produce, easy to store, and transportable without refrigeration. A long-term effort and commitment to providing resources must be maintained and increased to achieve the goal of a malaria vaccine candidate where ionizing radiation as a tool to prepare is seemingly feasible. Received: 20 November 2010; Revised: 11 July 2011; Accepted: 01 August 201

The Feasibility of Gamma Irradiation for Developing Malaria Vaccine

Malaria, a plasmodial disease, causes more than one million deaths per year and has a significant public health impact. Improved access to prompt treatment with effective antimalarial drugs need to be conducted for prevention of infection in high risk groups. However, the parasite as causal agent has exhibited a potential danger of wide-spread resistances. This warning has directed attention to the study of alternative methods of protection against the disease, among them is to do the immunization. A deeper understanding of the nature and regulation of protective immune mechanisms against this parasite will facilitate the development of much needed vaccines. Developing a malaria vaccine remains an enormous scientific, technical, and financial challenge. Currently a vaccine is not fully available. Among the practical applications of radiobiological techniques that may be of considerable interest for public health is the use of ionizing radiation in the preparation of vaccines. Convincing data were reported that sporozoites of Plasmodium berghei irradiated with X- or gamma-rays, provide an antigenic stimulus effective to induce a protective immune response in mice and rats against subsequent sporozoite infection. Irradiated parasites are better immunogens than killed ones and although non-infective they are still metabolically active, as shown by continued protein and nucleic acid synthesis. There is a substantial number of data from human studies demonstrating that sporozoites attenuated by radiation are potent inducers of protective immunity and that they are safe and do not give rise to the asexual erythrocytic infections that cause malaria. This vaccine is relatively inexpensive to produce, easy to store, and transportable without refrigeration. A long-term effort and commitment to providing resources must be maintained and increased to achieve the goal of a malaria vaccine candidate where ionizing radiation as a tool to prepare is seemingly feasible. Received: 20 November 2010; Revised: 11 July 2011; Accepted: 01 August 201

In Vitro Infectivity Study of Cryopreserved Irradiated Intraerythrocytic Form of Plasmodium falciparum

In control human malaria infection studies using irradiated Plasmodium falciparum, the cell bank of irradiated P. falciparum infected erythrocytes is needed. The cell banking methods represent an obvious way to obtain suitable material for blood stage Plasmodium. In a cell bank development of irradiated Plasmodium infected erythrocytes, the ability to cryopreserve procedure of Plasmodium is important to recover the infectivity of irradiated Plasmodium. This study aims at evaluating the in vitro infectivity of cryopreserved irradiated intra-erythrocytic form  P. falciparum. A protein profile investigation using Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) of cryopreserved  P. falciparum also conducted in this study to know the cryopreserved effect on the protein of irradiated P. falciparum. Plasmodium falciparum of 3D7 strain in human erythrocytes was maintained in invitro continuous culture. When the percentage of parasites was 10-20%, the culture was harvested and irradiated with gamma rays at a dose of 175 Gy. Irradiated P. falciparum then was mixed with cryopreserved solution and stored in -80 °C for one hour before transferred into liquid nitrogen for 20, 40 and 60 days. After being stored the irradiated P. falciparum was thawed and cultured for 20 days. The percentage of parasitaemia was enumerated by examining Giemsa stained thin blood films prepared for 20 days after initiation of culture. Results showed that storage time significantly (p<0.05) influence the percentage of parasitaemia. The cooling procedure and cryopreservation media may affect this study results. It also showed that there was insignificant difference of  P. falciparum protein profile in all storage times. Overall it can be assumed that the irradiated P. falciparum still kept their infectivity after stored in liquid nitrogen for 60 days. Further study using different cooling procedure and different formula of cryopreservation media with a longer storage time should be conduct to validate this study results

DOSIS INAKTIF DAN KADAR PROTEIN Klebsiella pneumonia K5 HASIL IRADIASI GAMMA

Tujuan dari percobaan ini adalah untuk mengetahui dosis inaktif dan kadar protein sel bakteri Klebsiella pneumonia K5 hasil iradiasi gamma. Tahapan percobaan adalah iradiasi kultur bakteri dengan dosis 0, 100, 200, 400, 600, 800, 1.000 dan 1.500 Gy (laju dosis 1089,59 Gy/jam). Penentuan dosis inaktif diketahui dengan metode drop test dan kadar protein diukur dengan metode Lowry. Hasil percobaan menunjukkan bahwa dosis inaktif sel bakteri K. pneumoniae adalah antara 600 Gy – 1.500 Gy. Iradiasi dengan dosis berbeda pada kultur bakteri menunjukkan adanya perubahan konsentrasi protein sel bakteri yang tidak menentu dan adanya pengaruh yang nyata dosis radiasi terhadap kandungan protein

Polymorphism of XRCC1 Gene Exon 6 (Arg194Trp) in Relation to Micronucleus Frequencies in Hospital Radiation Workers

The genetic polymorphism of DNA repair gene plays some important role in regulating individual sensitivity to ionizing radiation, maintaining DNA integrity, and preventing cancer and DNA damage.XRCC1 as one of the members ofbase excision repair (BER) is involved in the repairement of oxidized bases and single-strand breaks DNA after exposure by ROS, including ionizing radiation. This study was aimed to examine the correlation between XRCC1 exon 6 gene polymorphism and MN frequency in radiation workers and their relation to age, gender, smoking status and years of exposure. This study involved 81 hospital radiation workers and 20 controls from several hospitals in Indonesia. Genotyping of XRCC1exon 6 gene polymorphism and MN assay 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 frequency was significantly higherin the exposed workers than in the controls (15.38±7.72 versus 9±5.49; p = 0.001).Radiation workers with heterozygous alleles for XRCC1 polymorphisms showed a significantly higher MN frequency than controls with the same genotypes (17.5±8.36 versus 7.44±5.05; p = 0.002). The confounding factors, like gender and age, were significantly associated with increased MN frequency both in radiation workers and controls. Smoking status was significantly associated with MN frequency in the controls only, while years of exposure did not affect MN frequency either in radiation workers or controls. These results suggest that the genetic polymorphism of XRCC1 gene exon 6 with a mutant heterozygous/ CT variant demonstrated an association with the extent of DNA damage in the hospital radiation workers in this study. In the subsequent studies, it is necessary to examine the DNA repair genes polymorphism in populations with controlled non-genetic factors, such as lifestyles, environments, and exercises that affect the MN frequency as a biomarker of DNA damage

Assessment of Individual Radiosensitivity in Inhabitants of Takandeang Village - A High Background Radiation Area in Indonesia

People living in high background radiation area (HBRA) possibly developed the radioadaptive response (RAR) phenomena. Mamuju area in West Sulawesi Indonesia also known as the HBRA in Indonesia due to high natural uranium contents. It is possible that RAR was developed in Mamuju inhabitants. To prove this hypothesis, here in this study evaluation of the individual radiosensitivity in Takandeang Village, Mamuju inhabitants using G2 micronucleus (MN) assay was conducted. Association between blood groups and TP53 Arg72Pro polymorphism with individual radiosensitivity also evaluated in this study. Using G2 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 micronucleus induced by radiation found in control group (CG) was set as the cut-off value to determine the individual radiosensitivity in all samples. The radiation induced MN higher than the mean CG + 1SD CS 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. Results showed that four individuals in Takandeang Village inhabitants were having a milder radiosensitive phenotype, whilst the other was categorized as normal radiosensitive. The similar finding also found in control samples. Our study failed to find a correlation between radiosensitivity and blood group also 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.       

Molecular and in silico Study of TP53 Codon 72 Polymorphism (rs1042522) in a Population Exposed to High Background Radiation in Mamuju-West Sulawesi

The evaluation of the tumor protein p53 (TP53) codon 72 polymorphism (rs1042522) status in a population exposed to high background radiation was performed in this study. Real-time polymerase chain reaction (Q-PCR) was used to genotype the rs1042522 polymorphism in 100 subjects from Takandeang, Salleto, and Ahu villages in Mamuju district, West Sulawesi. An in silico study was then conducted to identify the potential effects of the proline substitution associated with this polymorphism on protein stability. The in silico analysis was performed using three different computational tools, namely I-Mutant Suite, iStable, and Protein Variation Effect Analyzer (PROVEAN). Secondary and three-dimensional (3D) structural models for wild-type (WT) and variant TP53 were generated to predict potential structural changes in the protein. Electrostatic surface charge calculations were also performed to identify changes in the electrostatic charge of codon 72. The Pro72 and Arg72 frequencies among the inhabitants in the Takandeang, Salleto, and Ahu villages, who are Mandarese Austronesian-speaking ethnic group members, were 0.56 and 0.44, respectively. The in silico analysis revealed no negative effects on protein stability due to the proline substitution at codon 72, although molecular modeling showed several differences in the secondary and 3D structures of the TP53 variant compared with the structure of WT TP53. To determine the impact of the proline-coding allele on individual sensitivity to radiation exposure, we compared the micronucleus (MN) frequencies of each genotype. The results showed that the MN frequencies in individuals harboring the proline-coding allele were not significantly higher than those expressing the arginine-coding allele. In conclusion, this study revealed that the proline-coding allele for codon 72 of the TP53 gene represented the predominant genotype among Takandeang, Salleto, and Ahu villages inhabitants. The present study also demonstrated that individuals who carried the proline-coding allele were not more sensitive to radiation compared with those expressing the arginine-coding allele for codon 72 of the TP53 gene