• Journal of Radiation Protection and Research
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• 제48권4호
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• pp.197-203
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• 2023

Background: The thermoluminescent dosimeter (TLD) and Monte Carlo (MC) dosimetry are carried out to determine the occupational dose for personnel in the handling of ¹²⁵I seed sources. Materials and Methods: TLDs were placed in different layers of the Alderson-Rando phantom in the thyroid, lung and also eyes and skin surface. An ¹²⁵I seed source was prepared and its activity was measured using a dose calibrator and was placed at two distances of 20 and 50 cm from the Alderson-Rando phantom. In addition, the Monte Carlo N-Particle Extended (MCNPX 2.6.0) code and a computational phantom with a lattice-based geometry were used for organ dose calculations. Results and Discussion: The comparison of TLD and MC results in the thyroid and lung is consistent. Although the relative difference of MC dosimetry to TLD for the eyes was between 4% and 13% and for the skin between 19% and 23%, because of the existence of a higher uncertainty regarding TLD positioning in the eye and skin, these inaccuracies can also be acceptable. The isodose distribution was calculated in the cross-section of the head phantom when the ¹²⁵I seed was at two distances of 20 and 50 cm and it showed that the greatest dose reduction was observed for the eyes, skin, thyroid, and lungs, respectively. The results of MC dosimetry indicated that for near the head positions (distance of 20 cm) the absorbed dose rates for the eye lens, eye and skin were 78.1±2.3, 59.0±1.8, and 10.7±0.7 µGy/mCi/hr, respectively. Furthermore, we found that a 30 cm displacement for the ¹²⁵I seed reduced the eye and skin doses by at least 3- and 2-fold, respectively. Conclusion: Using a computational phantom to monitor the dose to the sensitive organs (eye and skin) for personnel involved in the handling of ¹²⁵I seed sources can be an accurate and inexpensive method.

• 한국산업보건학회지
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• 제20권1호
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• pp.29-40
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• 2010

This study was aimed at investigating the gene expression profile in basal ganglia of cadmium exposed rat based on cDNA array analysis. For cDNA array analysis, adult Sprague-Dawley male rats (350 ${\pm}$ 25 g) were intraperitoneally injected with 2.0 mg/kg body weight/day of CdCl2 (0.3 ml) for 5 days. For doserelated gene expression analysis rats were intraperitoneally injected with 0.0, 0.1, 0.3, 1.0 mg/kg body weight/day of CdCl$_2$ for 5 days. Control rats were injected with equal volume of saline. Cadmium concentration of brain was analyzed by atomic absorption spectrophotometer. For cDNA array, RNA samples were extracted from basal ganglia and reverse-transcribed in the presence of [${\alpha}$32P]-dATP. Membrane sets of the Atlas Rat 1.2 array II and Toxicology array 1.2 (Clontech, Palo Alto, CA) were hybridized with cDNA probe sets. RT-PCR was employed to validate the relative gene expression patterns obtained from the cDNA array. Northern blot hybridization methods were employed to assess the dose-related gene expression. Among the 2352 cDNAs, 671 genes were detected in both array sets and 63 genes of 38 classes showed significant (more than two fold) changes in expression. Thirty five of these genes were up-regulated and twenty eight were down-regulated in the cadmium exposed group. According to the dose-related gene expression analysis, heat shock 27 kDa protein (HSP27), neurodegeneration-associated protein 1 (Neurodap 1) genes were significantly up-regulated and melatonin receptor 1a (Mel1a), Kinesin family member 3C (KIF3C), novel kinesinrelated protein (KIF1D) genes were significantly downregulated even in the low-dose of cadmium exposed group (0.1 mg/kg body weight/day). Conclusions Sixty three genes detected in this study can give some more useful informations about the cadmium-induced neurotoxicity in the basal ganglia. As well as, HSP27, Neurodap1, Mel1a, KIF3C and KIF1D genes may be useful for the study of the cadmium-induced neurotoxicity because these genes showed dramatic changes of mRNA levels in response to the low dose of cadmium exposure.

• Journal of Microbiology and Biotechnology
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• 제11권3호
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• pp.524-528
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• 2001

The measurement of radiation response using simple and informative techniques would be of great value in studying the genetic risk following occupational, therapeutic, or accidental exposure to radiation. When patients receive radiation therapy, many suffer from side effects. Since each patient receives a different dose due to different physical conditions, it is important to measure the exact dose of radiation received by each patient to lessen the side effects. Even though several biological dosimetric systems have already been developed, there is no ideal system that can satisfy all the criteria for an idean dosimetric system, especially for low-dose radiation as used in radiation therapy. In this study, an SOS Chromotest of E. coli PQ37 was evaluated as a novel dosimeter for low-dose gamma-rays. E. coli PQ37 was originally developed to screen chemical mutagens using the SOS Chromotest-a colorimtric assay, based on the induction of ${\beta}$-galactosidase ue to DNA damage. The survival fraction of E. coli PQ37 decreased dose-dependently with an increasing dose of cobalt-60 gamma-rays. Also, a good linear correlation was found between the biological damage revealed by the ${\beta}$-galactosidase expression and the doses of gamma-rays. The expression of ${\beta}$-galactosidase activity that responded to low-dose radiation under 1 Gy was $Y=0.404+(0.089{\pm}0.3)D+(-0.018{\pm}0.16)D^2$ (Y, absorbance at 420 nm; D, Dose of irradiation) as calculated using Graph Pad In Plot and Excel. When a rabbit was fed with capsules containing an agar block embdded with E. coli PQ37 showed a linear response to the radiation doses. Accordingly, the results confirm that E. coli PQ37 can be used as a sensitive biological dosimeter fro cobalt-60 gamma-rays. To the best of our knowledge, this is the first time that a bacterium has been used as a biological dosimeter, especially for low-dose radiation.

• Tuberculosis and Respiratory Diseases
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• 제71권1호
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• pp.37-45
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• 2011

Background: Pulmonary emphysema (PE) is major cause of obstructive pulmonary function impairment (OPFI), which is diagnosed by spirometry. PE by high resolution CT is known to be correlated with OPFI. Recently, low dose CT (LDCT) has been increasingly used for screening interstitial lung diseases including PE. The aim of this study was to evaluate OPFI risks of subjects with PE detected by LDCT compared with those detected by simple digital radiography (SDR). Methods: LDCT and spirometry were administered to 266 inorganic dust exposed retired workers, from May 30, 2007 to August 31, 2008. This study was approved by our institutional review board and informed consent was obtained. OPFI risk was defined as less than 0.7 of forced expiratory volume in one second (FEV1)/forced vital capacity (FVC), and relative risk (RR) of OPFI of PE was calculated by multiple logistic regression analysis. Results: Of the 266 subjects, PE was found in 28 subjects (10.5%) by LDCT and in 11 subjects (4.1%) by SDR; agreement was relatively low (kappa value=0.32, p<0.001). FEV1 and FEV1/FVC were significantly different between PE and no PE groups determined by either SDR or LDCT. The differences between groups were larger when the groups were divided by the findings of SDR. When PE was present in either LDCT or SDR assays, the RRs of OPFI were 2.34 and 8.65, respectively. Conclusion: LDCT showed significantly higher sensitivity than SDR for detecting PE, especially low grade PE, in which pulmonary function is not affected. As a result, the OPFI risks in the PE group by LDCT was lower than that in the PE group by SDR.

• 한국산업보건학회지
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• 제32권2호
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• pp.102-110
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• 2022

Objectives: The purpose of this study is to analyze the content of N,N-dimethylformamide(DMF) in polyurethane coated gloves(PU-gloves) and to assess the dermal exposure generated by wearing them. Methods: We analyzed the concentrations of DMF in 12 gloves by EN16778 standard. The samples cut into pieces of about 10 by 10 mm and extracted with methanol in flask in an ultrasonic bath at 70℃. An aliquot of the extract is analyzed with GC-MS. The dose of dermal exposure was calculated by ECETOC TRA consumer 3.1 and compared with derived no effect level(DNEL) for systemic effects due to long term exposure by workers. The extracted amount of DMF by saline solution was compared with that by EN16778 standard. Results: The mean concentration of DMF in PU-gloves was 1,377 mg/kg(range 13~3,948 mg/kg). The concentration of DMF showed significantly differences by packing type, manufacturer, and price(p<0.05). The dose of dermal exposure was 0.0007~0.572 mg/kg body weight/day when the DMF content was 10~4,000 mg/kg. The DMF extracted by saline solution was around 11% for 8 hours. Conclusions: The risk of dermal exposure due to the residual DMF in the PU-gloves was not signifiant. But, the limit of 1,000 mg/kg in PU-gloves can be recommended for international standard and trading systems.

• Toxicological Research
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• 제17권
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• pp.135-138
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• 2001

Female Wistar rats were randomly divided into 5 groups: Control, received distilled water; Low lead, received 0.5 g/ιlead (as acetate) in drinking water; High lead, received 2.0 g/ιlead; Low lead + Minerals, received 0.5 g/ιlead in drinking water and received minerals (Ca$^{2+}$, 25 mg/kg/day; Fe$^{3+}$, 0.47 mg/ kg/day; Zn$^{2+}$, 0.33 mg/kg/day; Se, 0.83 $\mu\textrm{g}$/kg/day) by gavage; High lead + Minerals, received 2.0 g/ιlead and received the same minerals. Animals exposure to lead was from 10 days before mating till postnatal day 21; and the minerals was administered from the first day of pregnancy and during lactation. No statistical difference was found either in body weights or in blood lead levels between the pups received minerals and those only exposed to lead at the same dose. The developmental and behavioral teratological effects of lead on pups, such as time-lag of eye opening, pinna detachment, fur developing, incisor eruption, ear unfolding, and surface righting were observed in this study; and the minerals decreased the toxicity of lead either in low or in high lead exposure pups. The numbers of step-down were significantly increased in lead exposed animals, and the effect of intervention by the minerals was appeared only in the pups exposed to low lead. The ChAT activity and levels of glutamate and aspartate in hippocampus decreased in treated animals compared to control animals, no effect of intervention by the minerals was found. The results of this study indicate that the applied multi-minerals can alter the outcome of develop-mental lead poisoning in rats.s.s.s.

• 한국환경보건학회지
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• 제39권4호
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• pp.346-353
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• 2013

Objectives: The goal of this study is to identify the distribution of the foliar fluorine content of vegetation surrounding the area where hydrofluoric acid was accidently released in Gumi, Gyeongsangbuk-do on September 27, 2012. In addition, it also aims to estimate the concentration of hydrogen fluoride in the air on the day of the accident. Methods: Samples of plant leaves were collected on October 7, 2012 within 1 km from the site where the accident occurred. These samples were analyzed for soluble fluorine ion with an ion selective electrode. The ambient concentration of hydrogen fluoride was calculated using the fluoride content in the plant via the dose-rate equation (${\Delta}F$=KCT). Results: The arithmetic and geometric means of the concentrations were 2158.2 and 1183.7mg F $kg^{-1}$ for leaves and, 2.4 and 1.1 ppm HF for the air, respectively. The highest concentration of hydrogen fluoride in the air was 14.7 ppm, which is higher than the maximum concentration reported by the government (1 ppm) and the exposure limit (ceiling, 3 ppm). The concentrations of both fluorine and hydrogen fluoride decreased with increasing distance from the accident site and showed a significant decrease outside of a 500m radius from the site (p <0.05). Conclusions: The area around the accident site was highly polluted with hydrogen fluoride according to the results of this study. Considering the persistency of hydrogen fluoride in the environment, long-term monitoring and environmental impact assessment should be pursued.

• Annals of Occupational and Environmental Medicine
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• 제34권
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• pp.37.1-37.15
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• 2022

Background: This study investigated the effect of dispatch frequency on blood cadmium levels and the effect of blood cadmium levels on hypertension in male firefighters in a metropolitan city. Methods: We conducted a retrospective longitudinal study of male firefighters who completed the regular health checkups, including a health examination survey and blood cadmium measurements. We followed them for 3 years. To investigate the effect of dispatch frequency on blood cadmium levels and the effect of blood cadmium levels on hypertension, we estimated the short-term (model 1) and long-term (model 2) effects of exposure and hypothesized a reversed causal pathway model (model 3) for sensitivity analysis. Sequential conditional mean models were fitted using generalized estimating equations, and the odds ratios (ORs) and the respective 95% confidence intervals (CIs) were calculated for hypertension for log-transformed (base 2) blood cadmium levels and quartiles. Results: Using the lowest category of dispatch frequency as a reference, we observed that the highest category showed an increase in blood cadmium levels of 1.879 (95% CI: 0.673, 3.086) ㎍/dL and 0.708 (95% CI: 0.023, 1.394) ㎍/dL in models 2 and 3, respectively. In addition, we observed that doubling the blood cadmium level significantly increased the odds of hypertension in model 1 (OR: 1.772; 95% CI: 1.046, 3.003) and model 3 (OR: 4.288; 95% CI: 1.110, 16.554). Using the lowest quartile of blood cadmium levels as a reference, the highest quartile showed increased odds of hypertension in model 1 (OR: 2.968; 95% CI: 1.121, 7.861) and model 3 (OR: 33.468; 95% CI: 1.881, 595.500). Conclusions: We found that dispatch frequency may affect blood cadmium levels in male firefighters, and high blood cadmium levels may influence hypertension in a dose-response manner.

• Journal of Preventive Medicine and Public Health
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• 제37권2호
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• pp.157-165
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• 2004

Objectives : This study aimed to investigate the toxic effects of chromium (VI) on the placental function and reproduction in rats. For the study, the placental prolactin-growth hormone (PRL-GH) gene expression, placental trophoblast cell differentiation and reproductive data were analyzed. Methods : The pregnancies of F344 Fisher rats were checked by the presence of a copulatory plug or sperm in the vaginal smear, which was defined as day 0 of the pregnancy. Pregnant rats were divided into the three groups. The control group was given tap water (chromium level < 0.001 ppm) and the remaining groups were given 250 or 750 ppm of chromium (VI) [as potassium dichromate], from day 7 to 19 of the pregnancy. Rats were sacrificed at days 11 and 20 of pregnancy. The mRNA levels of PRL-GH and Pit-1a and b isotype genes were analyzed by Northern blot hybridization and reverse transcription-polymerase chain reaction (RT-PCR). The hormonal concentration was analyzed by radioimmunoassay, and the differentiation of placental trophoblast cells were observed by histochemical studies. Reproductive data, such as placental and fetal weights, pregnancy period, and litter size, were surveyed at day 20 of pregnancy and after birth. A statistical analysis was carried out using the SAS program (version 8.1). Results : The mRNA levels of the prolactin-growth hormone (PRL-GH) family of genes were dose dependently reduced by chromium exposure. The mRNA levels of Pit-1a and b isotype genes that induce the expression of the PRL-GH family of genes were also reduced by chromium exposure. The PRL-GH hormonal concentration in the rat placenta, fetus and maternal blood were decreased by chromium exposure. In the middle stage of pregnancy (day 11), a high dose of chromium suppressed the differentiation of spongiotrophoblast cells that secret the PRLGH hormones. In the last stage of pregnancy (day 20), a high dose of chromium induced apoptosis of placental cells. Reproductive data, such as placental and fetal weights, litter size, were reduced, but the pregnancy period was extended in the group exposed to chromium compared with the controls. Conclusion : Chromium (VI) disrupts the ordered functions of the placenta, which leads to reproductive disorders in rats.

• Tuberculosis and Respiratory Diseases
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• 제39권2호
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• pp.131-140
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• 1992

유리규산과 자연산 석탄분진의 투여량과 관찰기간에 따른 폐조직과 hydroxyproline 량의 변화를 알아보기 위하여 대조군의 흰쥐에는 생리식염수 0.5ml를 기관지내에 주입하였고 실험군에는 생리식염수 0.5ml에 자연산석탄분진과 유리규산분진이 각각 10 mg, 30 mg, 50 mg씩 함유되도록 혼탁액을 만들어 이를 대조군과 같은 방법으로 주입한후 3주째와 20주째에 실험동물을 도살하여 젖은폐의 무게, 폐조직의 hydroxyproline량 그리고 폐의 조직학적 변화를 관찰한 바 아래와 같은 결과를 얻었다. 1) 자연산석탄분진 10 mg과 30 mg 투여군의 3주째를 제외한 모든 실험군의 젖은폐의 무게는 대조군에 비하여 유의하게 증가하였고(p<0.05), 유리규산 분진투여군에서는 20주째에 같은량의 자연산석탄분진을 투여한 군에 비하여 그리고 같은량의 유리규산분진을 투여한 군에서는 3주째에 비하여 20주째 젖은폐의 무게가 현저히 증가하였다(p<0.05). 2) 자연산석탄분진과 유리규산분진을 투여한 실험각군의 hydroxyproline 20주째에 대조군에 비하여, 그리고 동일한 분진의 같은량을 투여한 군에서는 3주째에 비하여 20주째 유의하게 증가하였으며(p<0.05), 유리규산분진 30 mg과 50 mg 투여군은 20주째에 같은량의 자연산석탄분진 투여한 군에 비하여 현저하게 증가하였다(p<0.05). 3) 분진의 투여량과 관찰기간이 같을때는 자연산석탄분진 투여군에 비하여 유리규산분진투여군에서 폐포간질과 폐포강내에 다형핵 백혈구, 섬유아세포, 대식세포가 증가하였고 폐포강내 삼출액이 관찰되었다. 진폐성결절은 3주째에 유리규산분진 30 mg과 50 mg 투여군에서만 관찰된 반면 20주째에는 모든 실험군에서 관찰되었다. 이상의 결과로 폐조직내 hydroxyproline 량의 증가와 진폐성 결절의 형성은 분진을 투여한 초기보다 후기에 현저하였고 자연산석탄분진보다 유리규산분진투여시 조기에 진폐증이 발생됨을 경험하였다.