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Objective To investigate the mechanism of fractionated low-dose ionizing radiation (LDIR) in the induction of EA.hy926 cell senescence. Methods EA.hy926 cells were irradiated with X-ray at 0, 50, 100, and 200 mGy × 4, respectively, and cultured for 24, 48, and 72 h. Several indicators were measured, including the levels of cellular senescence-associated β-galactosidase (SA-β-gal) staining, mRNA levels of senescence-associated cell cycle protein-dependent kinase inhibitor genes CDKN1A and CDKN2A, reactive oxygen species (ROS), total antioxidant capacity (T-AOC), and phosphorylated H2A histone family member X (γ-H2AX). Results After 4 fractionated LDIR, compared with the control group, the treatment groups showed increased nucleus area, blurred cell edge, and increased SA-β-gal positive area (P < 0.05) at 24, 48 and 72 h. After 4 fractionated LDIR, the mRNA level of CDKN1A increased in the 100 and 200 mGy × 4 groups at 24 and 48 h (P < 0.05), and CDKN2A mRNA level increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). The fluorescence intensity of ROS increased in treatment groups at 24, 48, and 72 h after 4 fractionated LDIR (P < 0.05). After 4 fractionated LDIR, the T-AOC level increased in the 100 and 200 mGy × 4 groups at 24 h (P < 0.05), and T-AOC level increased in all treatment groups at 48 and 72 h (P < 0.05). After 4 fractionated LDIR, γ-H2AX fluorescence intensity increased in all treatment groups at 24 h (P < 0.05), and the fluorescence intensity increased in the 100 and 200 mGy × 4 groups at 48 and 72 h (P < 0.05). Conclusion Fractionated LDIR can induce cellular senescence in EA.hy926 cells by impacting the cellular oxidation-antioxidation and oxidative damage levels, and the effects were relatively evident at 100 and 200 mGy.
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@#<b>Objective</b> To investigate the effects of lowdose ionizing radiation (LDIR) on oxidative stress and damage repair in human bronchial epithelial (HBE) cells. <b>Methods</b> HBE cells were divided into 0, 50, 100, and 200 mGy groups, and cultured for 24 and 48 h after X-ray irradiation, respectively. The cell viability, levels of glutathione (GSH), malondialdehyde (MDA), and 8-hydroxy-2’-deoxyguanosine (8-OHdG), and transcriptional levels of DNA damage repair genes <i>PPP2R2D</i> and <i>TP53</i> were measured. <b>Results</b> At 24 h after irradiation, there was no significant difference in the cell viability between the dose groups and the control group (<i>P</i> > 0.05); all dose groups had significantly increased MDA level, dose-dependently decreased GSH level, dose-dependently increased 8-OHdG level, and significantly increased mRNA level of <i>PPP2R2D</i> gene (all <i>P</i> < 0.05); the mRNA expression level of <i>TP53</i> gene was significantly increased in the 50 mGy group (<i>P</i> < 0.05). At 48 h after irradiation, there were the highest cell viability, significantly decreased MDA and 8-OHdG levels, and significantly increased mRNA expression levels of <i>PPP2R2D</i> and <i>TP53</i> genes in the 50 mGy group compared with the control group (all <i>P</i> < 0.05); the GSH level in the 100 mGy group was significantly increased (<i>P</i> < 0.05). <b>Conclusion</b> LDIR, especially radiation at 50 mGy, can affect the oxidative-antioxidant level in HBE cells and the transcript-level differential expression of DNA damage repair genes.
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Objective:To analyze the serum lipid levels, and its influencing factors, of male residents around an uranium mine in order to provide a scientific basis for health risk assessment for such residents.Methods:With such a mine as the center, the surveyed subjects were divided into four groups as within 5, 10, 15 and 20 km of this mine, respectively. These male residents living around the mine were randomly selected as subjects. A health questionnaire survey was conducted among the subjects. The indicator such as height, weight and blood pressure were measured by means of the standard method. Peripheral venous blood was extracted from the subjects, and their venous blood glucose and serum lipid were detected. The levels of serum lipid and detectable rates of abnormal serum lipid were analyzed by using univariate analysis, and multivariate logistic regression analysis was used to analyze the influencing factors of dyslipidemia.Results:A total of 867 males at age 40 to 69 was included in the vicinity of the mine. The mean levels ( ± s) of TC, TG, LDL-C, and HDL-C were (5.46±1.11), (1.92±1.64), (3.19±1.02), and (1.39±0.43) mmol/L, respectively. 384 subjects with dyslipidemia were totally detected in the residents, and the detection rate was 44.29% (384/867). Of the residents with dyslipidemia, the majority was abnormal in two lipid related indexes (45.57%, 175/384). Univariate analysis result showed that there was statistically significant difference in TG level in different distance groups ( F=3.34, P<0.05). There were statistically significant differences in the abnormal detection rates of TG and HDL-C in subjects in different distance groups ( χ2=9.52, 10.18, P<0.05). The detection rates of dyslipidemia were significantly different in the groups of BMI, blood pressure and blood glucose ( χ2=45.91, 32.31, 11.42, P<0.05). Multivariate logistic regression analysis showed that excluding marital status and degree of education, the BMI, blood pressure and blood glucose all had an impact on dyslipidemia. The residents with overweight ( OR=2.08, 95% CI: 1.52-2.86) and obeseness ( OR=2.88, 95% CI: 1.58-5.24) had a higher risk for dyslipidemia than those with normal weight. The risks for dyslipidemia in the residents with hypertension ( OR=1.94, 95% CI: 1.45-2.60) and hyperglycemia ( OR= 2.17, 95% CI: 1.27-3.69) were higher than those with normal blood pressure and blood glucose, respectively. Conclusions:The detection rate of dyslipidemia is higher in male residents around the mine. The BMI, alcohol consumption, blood pressure, blood glucose and distance from the mine are influencing dyslipidemia and other relevant indexes. Overweight is an independent risk factor for dyslipidemia and its components. The distances from uranium mine has no significant effect on the dyslipidemia of male residents.
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With the development of nuclear energy and the wide application of ionizing radiation, more and more occupational populations and the public are exposed to low-dose ionizing radiation. Consequently, the research on human health effects of exposure to low-dose ionizing radiation, including carcinogenic and non-carcinogenic effects, have become a hot topic in the field of public health. The biological effects caused by low-dose ionizing radiation mainly depend on the physical property, duration, dose, and dose rate of ionizing radiation. At present, there is no consensus on the effects of long-term exposure to low-dose ionizing radiation on human health. This article reviews the research on the health effects of long-term exposure to low-dose ionizing radiation at home and abroad, and provides a scientific basis for research on the health effects, influence mechanism, and protection strategies of long-term exposure to low-dose ionizing radiation.
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Objective To survey the basic situation of diagnosis and treatment in clinical nuclear medicine across Guangdong province,evaluate the risks of exposure to the radiation workers and public and explore the countermeasures to control radiation exposre.Methods A survey team was set up to survey,by filling questionnaires,the basic information on nuclear medicine practices for workers,equipment,radionuclide,frequency and dose to workers and radiation protection measures.Results A total of 71 nuclear medicine institutions was involved in the survey with 733 radiation workers in 2016 in Guangdong.The average annual effective dose to nuclear medicine workers was (0.55±0.66) mSv per year.The total pieces of nuclear medical equipment was up to 189 in 2016 including 59 SPECT/CT scanners (5 SPECT),28 PET/CT scanners and 54 thyroid scanners.Total activity of 1.15× 10s MBq in radiopharmaceuticals was used in 325 903 examinations and treatments with the number of frequency of 2.97 examinations per 1 000 population.Concluions There have been a rapid progress in practice of nuclear medicine over the past 20 years in Guangdong province with departments of nuclear medicine set up in 18 of 21 cities.Compared with 1998,the activity in radiopharmaceuticals used has increased by 414％ in 2016 and the number of frequency of examination and treatment has increased by 111％.The rapid expansion of nuclear medicine practice has also caused potential risks of radiation to the public and environment.
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Objective@#To investigate the distribution of gross α and gross β radioactive levels in drinking raw water from different regions of Guangdong province, and to establish the radioactive level base line value in raw water.@*Methods@#The samples from 191 drinking water sources in use in Guangdong province were collected in rainy season and dry season, respectively, and determined and analyzed under the standard examination method for drinking water-radiological parameters (GB/T 5750.13-2006). The levels of gross α and gross β radioactivity were evaluated under the standard for drinking water quality (GB 5749-2006).@*Results@#A total of 377 raw water samples were taken, including 189 samples in rainy season and 188 samples in dry season, in which 186 samples were matched between rainy season and dry season. In dry season, the gross α levels ranged from 0.008 Bq/L to 0.582 Bq/L, averaged at (0.034±0.060) Bq/L, while the gross β levels ranged from 0.014 Bq/L to 0.637 Bq/L, averaged at (0.108±0.091) Bq/L. In rainy season, the gross α levels ranged from 0.008 Bq/L to 0.402 Bq/L, averaged at (0.045±0.064) Bq/L, while the gross β levels ranged from 0.014 Bq/Lto 0.848 Bq/L, averaged at (0.125±0.128) Bq/L. The gross α and gross β radioactivity levels of other samples were much lower than the guidance values in the national radioactivity standards on drinking water radioactivity, except for a sample from Shanwei area. The gross α and gross β radioactivity levels in the rainy season were higher than in the dry water season, and the gross α radioactivity levels in the rainy season were significantly higher than in the dry water season. There were significant differences in gross α and gross β radioactivity levels in rainy(Frainy season=1.819, 2.709, P<0.05) and dry season (Fdry season=1.985, 8.461, P<0.05)in different water systems, and the levels of gross α and gross β radioactivity in the rivers in western Guangdong were the highest. The gross α and gross β radioactivity levels of groundwater in rainy season were higher than in river water and lake water, and the gross α and gross β radioactivity levels in river water were higher than in lake and reservoir water, with the statistically significant differences(Ftotal α=39.323, Ftotal β=25.911, P<0.05), the gross α and gross β radioactivity levels in dry season were higher than in river water and lake water, with the statistically significant difference(Ftotal α=11.520, Ftotal β=28.435, P<0.05). The highest radioactivity levels is in groundwater, followed by river water, and the lowest is in lake and reservoir water.@*Conclusions@#The natural radioactivity background levels in drinking raw water in Guangdong province is lower than the limit value on drinking water stipulated by our country. The radioactivity levels in raw water in western Guangdong is significantly higher than in other water systems, and the radioactivity level in river water is also significantly higher than in lake and reservoir water.
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Objective To obtain the information on the frequency of diagnostic X-ray examinations in Guangdong province in order to provide reference data for the rational application of diagnostic radiology.Methods A typical stratified sampling method was used to select 56 medical institutions in 7 districts in Guangdong province for the survey of the frequencies of diagnostic X-ray examinations.Multiple linear regression analysis was performed using the relevant variables of the surveyed sample (total number of hospitals,number of outpatients,number of inpatients,number of radiation workers,and number of diagnostic equipment).The dependent independent variables were fitted to the linear regression equation to estimate the frequency of routine diagnostic X-ray examinations and diagnostic CT examinations and the total frequency of diagnostic medical X-ray examinations in Guangdong province in 2016.Results By the largest percentage contribution,chest radiography accounted for 60.84％ of the routine diagnostic X-ray examinations,brain scans 28.03％ of diagnostic CT examinations,and cardiovascular interventions 48.83％ of interventional radiology.For the group of above 40 years old,the largest percentage contributions were,respectively,routine diagnostic X-ray examination 47.95％,diagnostic CT examinations 65.41％,and interventional radiology 75.64％.All types of medical X-ray examinations are concentrated in the tertiary and secondary hospitals.Based on this survey,the examination frequencies for 2016 in Guangdong were estimated to be,respectively,diagnostic X-ray examination 699 examinations per 1 000 population and CT diagnostic 231 examinations per 1 000 population,with the total of 992 examinations per 1 000 population.Conclusions This survey was completed to a limited degree and less investment.The results showed that the diagnostic radiology in Guangdong province is developing with increased frequencies,with wide varieties of X-ray examination types in the tertiary and secondary hospitals.Relevant competent defpartments should pay attention to strengthening the radiation protection of examined individuals and actively providing guidance on the correct and rational applicc ation of diagnostic radiology so as to achieve profit and avoid disadvantages.
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OBJECTIVE: To explore the effect of long-term low-dose ionizing radiation exposure on arterial vascular elasticity in female residents. METHODS: A cluster random sampling method was used,95 female residents in 2 regions with high external γ radiation dose rate in the high radiation background area( HBRA) in Yangjiang City were selected as the HBRA group,and 96 female residents from the control area( CA) in Enping City were chosen as the CA group. The height,body mass,waist circumference,hip circumference and blood pressure were measured in individuals of these two groups. The fasting blood samples of elbow vein were collected to measure high-density lipoprotein cholesterol( HDL-C),low-density lipoprotein cholesterol( LDL-C),triglycerides( TG) and blood glucose. The cardio-ankle vascular index( CAVI) was measured using the blood pressure and pulse check device. RESULTS: The CAVI of the CA and HBRA groups were( 8. 09 ±1. 03) and( 8. 35 ± 1. 60) m/s,respectively. The abnormal rates of CAVI were 25. 00% and 29. 47%,respectively. The results of multiple linear regression analysis showed that after adjustment for age,HDL-C,LDL-C,TG,hypertension,abnormal glucose metabolism and abdominal obesity,the CAVI adjustment mean values of the CA and HBRA groups were8. 19 and 8. 25 m/s,respectively. The HBRA group was about 0. 73% higher than the CA group,but the difference was not statistically significant( standardized partial regression coefficient = 0. 021,P > 0. 05). After matching age of both groups,the difference of the adjusted mean of CAVI between the two groups was not statistically significant( P > 0. 05).CONCLUSION: Long-term low-dose radiation exposure is not associated with atherosclerosis in female population.
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Objective To explore the effect of long-term low dose ionizing radiation on telomere length in adults. Methods Forty female residents aged more than 55 years old from high level natural background radiation area in Yangjiang city and forty age-matched female residents from control area in Enping city were selected by quota sampling as high background group and control group, respectively. Genomic DNA was isolated from their peripheral blood. Telomere length was determined using real time q-PCR. The t-test was used to compare the square roots of the means of two groups. The individuals were divided into four groups based on ages ( 55 -, 60 -, 65 - and ≥70 ) and four groups based on BMI ( <18. 5, 18. 5-23. 99, 24. 0 -27. 99 and ≥28. 0). After adjusting age and BMI, multivariate linear regression analysis was performed to study the relationship between telomere length and cumulative exposure dose. The individuals were divided into longer telomere length group (≥2 ) and shorter telomere length group ( <2). Logistic regression analysis was performed to study the relationship between telomere length and cumulative exposure dose. Results The average cumulative dose was(169. 52 ± 27. 43)mSv for high background group and(47. 52 ± 6. 50)mSv for control group. The telomere length of high background group was( 1. 98 ± 1. 25 ) , shorter than that of control group ( 2. 69 ± 1. 44 ) with statis-tically significant difference(t=2. 24, P <0. 05). The multivariate linear regression analysis revealed that the effect of cumulative dose on telomere length was not significant ( P>0. 05 ) . Association between telomere length and cumulative dose was explored through Logistic regression, and odds ratio was taken as 0. 992(95% CI, 0. 985-0. 999 ) . There was a weak inverse association between telomere length and cumulative dose, because the odds ratio ( OR) was very close to 1. Conclusions No obvious dose-effect relationship between telomere length of residents and cumulative radiation doses was found. But the long-term low dose ionizing radiation may lead to the shortening of the telomere length in adults.
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Objective To establish the immortalized cell lines of peripheral blood lymphocytes for old male residents in high background radiation area(HBRA)in Guangdong,China,in order to preserve the specific genomic resources of residents in HBRA for the further genetic and molecular biological study on HBRA.Methods The peripheral blood samples of 20 old male residents in HBRA were collected after informed consent.The immortalized B lymphoblastoid cell lines,2 for each resident,were established with Epstein-Barr virus.After being frozen and recovered,the cell viability,the contamination of bacterium and mycoplaama were analyzed.The stabilization of cell lines was decided by comparing the karyotypes of the peripheral blood lymphocytes and the cell lines.Results 40 cell lines for 20 residents in HBRA were successfully established.The recovery rate of cell lines after being frozen was 100%.All the cell viablity after recovery was higher than 90%.and no contamination of bacteria and mycoplasma occurred.The karyotypes of the 20th generation cell lines were not change.Conclusion The immortalized cell lines established in this study could provide biological resources for further study on genetics and molecular biology in HBRA.