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Exposure to ionizing radiation intervenes in genomic stability and gene expression,resulting in the disruption of normal metabolic processes in cells and organs by causing complex biolog-ical responses.Altered genomic variations,gene expression and metabolite concentrations in blood or tissue samples reflect systemic radiation damage.With the application of new techniques and exten-sive study on the mechanisms for ionizing radiation damage,related indicators such as chromosomal variation,gene expression,lipid and metabolism are being recognized and promise to be the markers for early diagnosis and prognosis of radiation exposure.Therefore,this article reviews recent progress in and potential applications of biomarkers related to ionizing radiation injury.
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Objective:To explore the changes of oxidative stress(OS),DNA damage and the occurrence of cellular premature aging of human immortalized keratinocytes(HaCaT)after that was radiated by X-ray with different doses.Methods:HaCaT cells were radiated by X-ray,and they were divided into 0 Gy group,5 Gy group and 10 Gy group according to the irradiation dose.The levels of intracellular reactive oxygen species(ROS)were detected by 2,7-Dichlorofluorescein diacetate(DCFH-DA)fluorescent probe,and the intracellular content of malondialdehyde(MDA)of lipid peroxidation products and the activity of superoxide dismutase(SOD)were measured by colorimetry.Immunofluorescence staining was used to detect the phosphorylated histone 2A variant(γ-H2AX)in HaCaT cells that were radiated by X-ray with different doses.Cell count kit-8(CCK-8)was used to detect the effect of X-ray with different doses on the proliferation of HaCaT cells after X-ray with different doses radiated them.β-Galactosidase staining was used to detect the proportion of premature aging cells.The changes of p21 and p53 protein expressions after X-ray irradiation were detected by Western blot.Results:After HaCaT cells were radiated by X-ray for 24h,the fluorescence intensity of 2',7'-Dichlorofluorescein(DCF)in 5 Gy and 10 Gy groups were significantly higher than that in the 0 Gy group,and the MDA contents of them were significantly higher than that in the control group,and the SOD activities of them were significantly lower than that in the control group(F=38.35,92.22,5.22,P<0.05),respectively.The change of γ-H2AX focus showed a dose-dependent significant increase at 1 h after irradiation,and the difference between them and control group was statistically significant(F=129.3,P<0.05).At 6h,24h and 48h after X-ray radiated HaCaT cells,the cell proliferation abilities of 5 Gy group and 10 Gy group were significantly decreased than that of 0 Gy group(F=116.41,62.20,34.29,P<0.01),and the β-Galactosidase activity of the two groups were significantly increased than that of 0 Gy group,and the difference was significant(F=1629.22,P<0.01).At 72h after X-ray with different doses radiated HaCaT cells,the expression levels of p21 and p53 proteins of 5 Gy group and 10 Gy group increased,and the differences of them among three groups were significant(F=104.4,66.69,P<0.01),respectively.Conclusion:Ionizing radiation can induce the occurrences of oxidative stress and DNA damage in HaCaT cells,and cause the occurrence of cellular premature aging.
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Objective:To explore the effects of estrogen receptor α (ERα) encoded by protein encoding gene ESR1 on the radiation resistance of breast cancer cells and their molecular mechanisms.Methods:The ESR1 overexpression plasmid was transfected into estrogen receptor (ER)-negative breast cancer cells. Then, the shRNA-ESR1 vector was introduced into ER-positive cell to establish models with different phenotype. The ATG5 mRNA level and protein expression levels of LC3B-I, LC3B-II, P62, FIP200, ATG5, ATG7, ATG12, Beclin1, ULK1 were detected using qPCR and Western blot techniques. Cell death was measured using flow cytometry. The radiation sensitivity was determined through the colony formation assay. The mortality of breast cancer cells under the autophagy gene knockdown and overexpression or treated with estrogen receptor inhibitor (TAM) combined with ionizing radiation were detected by trypan blue staining.Results:Under the condition of 8 Gy X-ray irradiation, the knockdown of ESR1 in ER-positive ZR75 breast cancer cells promoted cell death ( t = 3.49, 3.13, P < 0.05), while the overexpression of ESR1 in ER-negative MDA-MB-231 breast cancer cells inhibited cell death ( t = 4.16, 7.48, P < 0.05). Compared to the control group, the treatment with chloroquine increased the number of formed colonies of ESR1 knockdown ZR75 cells ( t = 8.49, P < 0.05), and inhibiting autophagy could reduce the death of ZR75 cells caused by ESR1 silencing. Under the treatment with ionizing radiation, the overexpression of ESR1 in MDA-MB-231 cells promoted protective autophagy, which, however, was reduced after ESR1 knockdown in ZR75 cells. Furthermore, it was observed that the knockdown of ATG5 in ZR75 cells was associated with reduced autophagy and an increase in cell death ( t = 4.19, 6.39, P < 0.05). In contrast, the overexpression of ATG5 in ZR75 cells reversed the increase in cell death caused by ESR1 knockdown ( t = 1.70, 4.65, P < 0.05). After the treatment of ER-positive ZR75 breast cancer cells with TAM, the expressions of ATG5 and ATG12 decreased, suggesting inhibited autophagy and an increase in cell death ( t = 18.70, P < 0.05). Furthermore, these processes were promoted by ionizing radiation ( t = 16.82, P < 0.05). Conclusions:The estrogen receptor encoded by ESR1 promotes protective autophagy of ER-positive breast cancer cells by increasing ATG5, further leading to radiation resistance in ER-positive breast cancer cells. Treatment with tamoxifen combined with ionizing radiation can increase the radiation sensitivity of ER-positive breast cancer cells.
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Objective:To investigate the effects of sleep disorders (SD) on the radiation injury of hematopoietic stem cells (HSCs) in bone marrow (BM).Methods:Totolly 56 C57BL/6J male mice aged 6-8 weeks were enrolled in this study. They were subjected to whole body irradiation of 60Co γ-rays with doses of 5.0 and 7.5 Gy. A SD model was established using a SD device. According to the random number table method, the mice were divided into seven groups: the control group (Con group), the SD group, the mere radiation group (IR group), the group of post-irradiation SD (IR+ SD group), the group of post-irradiation SD treated with phosphate buffer solution (IR+ SD+ PBS group), the group of post-irradiation SD treated with GSK2795039 (IR+ SD+ GSK group), and the group of post-irradiation SD treated with N-acetylcysteine (IR+ SD+ NAC group), with in eight mice each group. The changes in the peripheral blood of the mice after 5.0 Gy irradiation were detected using the collected tail venous blood, and the survival rates of the mice after 7.5 Gy irradiation were observed. The changes in the density and count of bone marrow cells were observed using hematoxylin and eosin (HE) staining. The number of hematopoietic stem cells in bone marrow (LSK cells), as well as their apoptosis level and changes in cell cycle, were detected using flow cytometry. Furthermore, indicators of LSK, such as reactive oxygen species(ROS) and mitochondrial-derived reactive oxygen species (mtROS), were analyzed. Nicotinamide adenine dinucleotide phosphate (NADP+ /NADPH) and glutathione (GSSG/GSH) were detected using an enzyme microplate reader in order to observe the oxidative stress level of LSK. Furthermore, flow cytometry was employed to sort the LSK cells from the mice, and flow cytometry was used to detect the expression of NADPH oxidase 2(NOX2) and cysteinyl aspartate specific proteinnase-1(Caspase-1), and polymerase chain reaction (PCR) was used to detect the expression of inflammatory factors such as NOX1-4, interleukin 1β (IL-1β), interleukin 6 (IL-6), interleukin 18 (IL-18), and tumor necrosis factor α (TNF-α). Results:Compared to the IR group, the IR+ SD group exhibited significantly slower recovery of white blood cells (WBC) and platelets (PLT) ( t = 4.39, 6.37, P < 0.05), the bone marrow cell count decreasing from (2.14 ± 0.38) × 10 7 to (3.59 ± 0.29) × 10 7 ( t = 8.55, P < 0.05), significantly decreased proportion of G 0-phase LSK cells, significantly increased proportion of apoptotic cells ( t = 7.53, 8.21, P < 0.05), and significantly increased DCFH-DA, MitoSOX, and NADP+ /NADPH ( t = 22.99, 29.47, 3.77, P<0.05). In the case of IR, SD further promoted the activation of NOX2 and led to increases in the mRNA expression of downstream inflammatory factors such as IL-1β, IL-6, IL-18, and TNF-α ( t = 6.95, 6.01, 8.39, 4.91, 5.56, P < 0.05). Inhibition of NOX2-ROS could prevent the SD-induced aggravation of post-irradiation hematopoietic injury. This significantly reduced the apoptotic rate of LSK cells and the expression of inflammatory factors, ultimately accelerating the hematopoietic recovery of LSK cells ( t = 9.24, 3.92, P < 0.05). Conclusions:SD can aggravate the IR-induced injury of hematopoietic stem cells in bone marrow, primarily by activating the NOX2-ROS-Caspase-1 axis. This will increase the levels of intracellular inflammatory factors and ROS, promote cell apoptosis, and ultimately inhibit the hematopoietic recovery of bone marrow.
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Radiation-induced damage to vascular endothelium is a major complication of radiotherapy and a primary cause of morbidity and mortality in the population exposed to radiation. Ionizing radiation-induced cellular senescence serves as a critical factor in damage to vascular endothelial cells. Therefore, understanding the mechanisms of cellular senescence caused by senescence-associated secretory phenotype (SASP), as well as its role in ionizing radiation-induced damage to vascular endothelial cells, is significant for preventing and treating ionizing radiation-induced damage to vascular endothelial cells. In this study, the relationship between SASP-related premature senescence and this ionizing radiation-induced damage was explored from the following aspects: the mechanisms behind ionizing radiation-induced damage to vascular endothelial cells, ionizing radiation-induced cellular senescence, and the role of SASP-related premature senescence in the ionizing radiation-induced damage to vascular endothelial cells, as well as potential targets.
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ABSTRACT Objective: To compare cancer mortality among workers exposed to gamma and X radiation and the general population of the city of São Paulo, as well as that of the subgroup monitored with those not monitored for gamma and X radiation in a work unit with ionizing radiation based in the city of São Paulo. Methods: Between 2016 and 2021, a retrospective open cohort study was carried out with workers who were employed from 08/31/1956 to 12/31/2016 based on data collected at the company and in official institutions. Standardized mortality ratios (SMR) were calculated by sex, age and calendar period of cancers grouped according to type, risk factor and organ system in two analyses: in the external analysis, the mortality of the study population was compared with that of the general population of the city of São Paulo; In the internal analysis, the mortality of the monitored subgroup was compared with that of the subgroup not monitored for gamma and X radiation. Results: The external mortality analysis showed SMR=0.224 (95%CI 0.208-0.240) and the healthy worker effect, while the internal mortality analysis showed SMR=0.685 (95%CI 0.618-0.758). Conclusion: This study showed lower cancer mortality among exposed workers when compared to mortality in the general population and the healthy worker effect. Among workers monitored for gamma and X radiation, cancer mortality was lower when compared to those not monitored.
RESUMO Objetivo: Comparar a mortalidade por câncer entre trabalhadores expostos à radiação gama e X e a população geral do município de São Paulo, bem como a do subgrupo monitorado com o não monitorado para radiação gama e X em uma unidade de trabalho sediada no município de São Paulo. Métodos: Entre 2016 e 2021 foi realizado estudo de coorte aberta retrospectiva com trabalhadores que tiveram vínculo empregatício desde 31/08/1956 até 31/12/2016 a partir de dados coletados na empresa e em instituições oficiais. Foram calculadas as razões de mortalidade padronizadas (RMP) por sexo, idade e período calendário de cânceres agrupados segundo o tipo, o fator de risco e o sistema orgânico em duas análises: na análise externa, comparou-se a mortalidade da população de estudo com a da população geral do município de São Paulo; já na análise interna, comparou-se a mortalidade do subgrupo monitorado com a do subgrupo não monitorado para radiação gama e X. Resultados: A análise externa de mortalidade mostrou RMP=0,224 (IC95% 0,208-0,240) e o efeito do trabalhador sadio, enquanto a análise interna de mortalidade mostrou RMP = 0,685 (IC95% 0,618-0,758). Conclusão: Este estudo mostrou menor mortalidade por câncer entre os trabalhadores expostos quando comparada com a mortalidade da população geral e o efeito do trabalhador sadio. Entre os trabalhadores monitorados para radiação gama e X, a mortalidade por câncer foi menor quando comparada com a dos não monitorados.
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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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Objective To examine the effects of ionizing radiation on blood pressure and electrocardiography among healthcare workers in department of cardiovascular diseases, and to provide a reference for formulating the protective interventions against radiation exposure. Methods A total of 127 healthcare workers with radiation exposure in the Department of Cardiovascular Diseases of The 904th Hospital of the Joint Logistics Support Force of the PLA from 2018 to 2022 were included in the observation group. Meanwhile, 127 age- and gender-matched healthcare workers without radiation exposure in the same department during the same study period were included in the control group. The systolic blood pressure, diastolic blood pressure, heart rate, and the detection rates of hypertension and abnormal electrocardiography were compared between groups. Results There were no significant differences between groups in mean age (t = 0.77, P > 0.05), sex (χ2 = 0.02, P > 0.05), prevalence of smoking (χ2 = 0.28, P > 0.05), and alcohol consumption (χ2 = 0.02, P > 0.05). There were significant differences between the observation and control groups in systolic blood pressure [(127.77 ± 15.43) mmHg vs. (111.23 ± 19.10) mmHg; t = 4.21, P < 0.05], diastolic blood pressure [(79.32 ± 8.23) mmHg vs. (69.91 ± 10.21) mmHg; t = 4.09, P < 0.05], prevalence of hypertension [17.32% (22/127) vs. 8.66% (11/127); χ2 = 4.21, P < 0.05], heart rate [(81.10 ± 11.27) beats/min vs. (70.45 ± 10.55) beats/min; t = 4.33, P < 0.05], and abnormal rate of electrocardiography [21.26% (27/127) vs. 10.24% (13/127); χ2 = 5.82, P < 0.05]. Conclusion Ionizing radiation affects blood pressure and electrocardiography among healthcare workers in department of cardiovascular diseases. The prevention and monitoring of radiation exposure and occupational physical examination should be improved among healthcare workers with exposure to radiation in the department of cardiovascular diseases, with aims to reduce the hazard of radiation exposure and protect the health of healthcare workers.
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Aim To investigate the protective effect of dimethyl fumarate on spleen injury induced by gamma radiation in mice and the related mechanism. Methods C57BL/6 mice were randomly divided into the blank control group, radiation model group and DMF administration group, which were administered once at 12 h before irradiation and once at 0. 5 h, 12 h, 24 h and 48 h after irradiation. The 30-day survival rate, body weight and pathological injury of spleen were measured after a one-time total body irradiation of Co 7 rays (8 Gy). TUNEL staining was used to detect apoptosis of spleen cells. Enzyme-linked immunoassay ( ELISA) was applied to detect the contents of TNF-a, IL-1 p, IL-6, IL-18, NLRP3 and AIM2 in spleen. Western blot test and immunofluorescence staining test was employed to verify the changes of NLRP3 and AIM2 contents in spleen tissue after irradiation. Results DMF could obviously improve the survival rate of irradiated mice, improve the weight loss of irradiated mice, re-duce the pathological injury of spleen, and inhibit the apoptosis of spleen cells after irradiation. ELISA results showed that DMF could significantly inhibit the increase of spleen inflammatory cytokines TNF-a, IL-lp, IL-6, IL-18 and inflammasome components NL-RP3 and AIM2 induced by irradiation. Western blot and tissue immunofluorescence staining also confirmed that DMF could inhibit the increase of NLRP3 and AIM2 inflammasome protein levels caused by irradiation. Meanwhile, NLRP3 agonist and AIM2 agonist could antagonize the radiation protection effect of DMF on spleen cells. Conclusion DMF can ameliorate spleen injury of Co 7-ray injured mice, and its mechanism is closely related to NLRP3/AIM2 inflamma-somes, which can be used as a potential protective drug for radiation injury.
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Objective To explore the differentially expressed mRNAs and related biological processes and pathways in fractional low-dose ionizing radiation (LDIR)-induced senescence of normal human bronchial epithelial (HBE) cells by high-throughput mRNA sequencing and bioinformatics techniques. Methods Senescence-associated β-galactosidase staining and senescence-associated secretion phenotype gene mRNA and protein expression levels were measured at 24 and 48 h after irradiating HBE cells 7 times at doses of 0, 50, 100, and 200 mGy, respectively. The differentially expressed genes were screened by high-throughput sequencing for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. Results The senescence-positive area of fractional low-dose irradiated HBE cells increased in a dose-dependent manner (P < 0.05). The mRNA levels and protein expression of transforming growth factor-β1(TGF-β1) and matrix metalloproteinase-9(MMP-9) genes were increased in the 100 mGy × 7 and 200 mGy × 7 groups at 24 and 48 h after the end of irradiation compared with the control group. High-throughput sequencing showed that there were 882, 475, and 1205 differentially expressed mRNAs in each dose group compared with the control group. GO analysis showed that the differentially expressed mRNAs in each dose group were mainly enriched in biological processes such as cell cycle regulation, regulation of nitrogen compound metabolic process, regulation of cell division and response to stimulus. KEGG analysis showed that the differentially expressed mRNAs were mainly enriched in the pathways of cell cycle, cell senescence, and ferroptosis. Conclusion Fractional LDIR induced senescence in HBE cells, and differentially expressed mRNA-associated biological processes and pathways in senescent cells are related to cell cycle and cell senescence.
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Objective To analyze the micronucleus rate of radiation workers and to provide accurate occupational health monitoring basis in radiation workers exposed to low-level ionizing radiation for a long time. Methods The radiation group consisted of 353 radiation workers who had been exposed to ionizing radiation during work, while the control group consisted of 41 radiation workers who had not yet been exposed to ionizing radiation before work. The cytokinesis-block micronucleus method was used to determine the micronucleus rate. Results The average micronucleus rate in the radiation group was significantly higher than that in the control group (t = −2.95, P < 0.05). In the radiation group, the micronucleus rate gradually increased with age, and the difference was statistically significant (F = 8.36, P < 0.05). The micronucleus rates of workers with > 10 and > 30 years of service were significantly higher than those of workers with < 10 years of service (χ2 = −44.79, −60.47, P < 0.05). The micronucleus rate in females was significantly higher than that in males (t = 3.93, P < 0.05). The micronucleus rates in the diagnostic radiology group and the industrial detection group were significantly higher than that in the control group (t = 3.51, 3.65, P < 0.05). Conclusion The micronucleus rate has increased among the radiation workers exposed to low-level ionizing radiation for a long time. It is necessary to further strengthen occupational health monitoring and radiation protection education for radiation workers, especially the medical workers that constitute the largest population of radiation exposure workers.
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Objective To understand the effects of long-term exposure to ionizing radiation on the health of radiation workers. Methods A total of 215 radiation workers were randomly selected and assigned to the exposure group and 197 non-radiation workers were assigned to the control group. The occupational health examination results of the two groups were compared and analyzed. Results The WBC count of the exposure group was lower than that of the control group (P＜0.05), while the abnormality rates of ocular lens, ECG, liver function, and thyroid function were significantly higher in the exposure group than in the control group (P＜0.05). In the exposure group, the abnormality rate of liver function was lower in females than in males, and the abnormality rate of hemoglobin level was higher in females than in males (P＜0.01). The abnormality rate of ocular lens increased with age (P＜0.01). The abnormality rate of hemoglobin level was different among different age groups (P＜0.01). The abnormality rate of ocular lens increased with increasing years of service. The abnormality rates of RBC count and hemoglobin level in the general radiotherapy group were higher than those in the interventional radiotherapy group (P＜0.01). Sex was the influencing factor for abnormal liver function (P＜0.01). Conclusion Prolonged exposure to low doses of ionizing radiation can adversely affect the health of radiation workers in medical institutions.
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Occupational exposure to ionizing radiation represents a critical factor contributing to health risks in workplaces. Previous experimental and clinical studies have demonstrated that ionizing radiation affects human health. Therefore, scientific assessment of health risk caused by ionizing radiation and effective protection against ionizing radiation are of great importance to formulate the preventive interventions against occupational exposure to ionizing radiation. This review summarizes the advances in the research on health effects, health risk assessment methods, and protective interventions of ionizing radiation. We call for research on the health effects of low-dose radiation, individual difference, and optimization of preventive strategies. In addition, improved mechanisms of health monitoring, periodical healthy examinations, and monitoring of radiation doses should be implemented. Moreover, strict compliance to operating procedures and occupational preventive interventions are recommended. These measures aim to minimize the potential harmlessness of occupational exposure to ionizing radiation, thereby safeguarding the health and safety of individuals exposed to ionizing radiation.
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Introducción: El uso de radiografías como elemento complementario para el diagnóstico es fundamental para la práctica profesional de todo cirujano dentista. Por tanto, es importante conocer no solo los beneficios de la radiología oral y los fundamentos de protección radiológica, sino también determinar su nivel de aplicación o la adherencia frente al cumplimiento de los aspectos normativos que regulan el uso de la radiación ionizante en odontología. Objetivo: Relacionar el conocimiento sobre los cuidados en radiología bucal, las ventajas y los peligros en la toma de radiografías con el cumplimiento de las normas de protección radiológica y radiación ionizante en estudiantes de odontología de una clínica dental docente. Métodos: La población de estudio estuvo constituida por 180 estudiantes del cuarto año de la carrera de odontología, que emplearon los equipos radiológicos en la clínica docente asistencial durante los años 2019 (segundo semestre) y 2020 (primer trimestre). Se tomó como muestra representativa a 104 estudiantes, incorporados al estudio mediante muestreo aleatorio simple. Se aplicaron dos instrumentos de recolección de datos, uno para evaluar el conocimiento (cuestionario) y otro para verificar el cumplimiento de normas (lista de chequeo) sobre la protección radiológica y el diagnóstico por imágenes en la práctica odontológica. Para el análisis estadístico se aplicó la prueba estadística chi cuadrado con un nivel de significancia del 95 %. Resultados: No se encontró relación estadísticamente significativa (p = 0,30) entre el conocimiento teórico sobre la protección radiológica y el diagnóstico por imágenes, respecto el cumplimiento de las normas que regulan su aplicación (p > 0,05). El 90 % de participantes tienen conocimientos entre regulares y excelentes. Sin embargo, solo el 32 % cumple las normas técnicas de protección sobre radiación ionizante en su práctica clínica. Conclusión: Los estudiantes de odontología tienen suficiente conocimiento sobre protección radiológica y diagnóstico por imágenes. Sin embargo, este conocimiento no se refleja en prácticas adheridas a las normas.
Introduction: The use of radiographs as a complementary element for diagnosis is fundamental to the professional practice of every dental surgeon. Therefore, it is important to know not only the benefits of oral radiology and the fundamentals of radiological protection, but also to determine their level of application or adherence to compliance with the regulatory aspects that regulate the use of ionizing radiation in dentistry. Objective: To relate the knowledge of oral radiology care, the advantages and dangers in taking radiographs with compliance with the norms of radiological protection and ionizing radiation in dental students of a dental teaching clinic. Methods: The study population consisted of 180 fourth year dental students who used the radiological equipment in the teaching dental clinic during 2019 (second semester) and 2020 (first quarter). A representative sample of 104 students was taken, incorporated into the study by simple random sampling. Two data collection instruments were applied, one to evaluate knowledge (questionnaire) and the other to verify compliance with standards (checklist) on radiological protection and diagnostic imaging in dental practice. For the statistical analysis the chi-square statistical test was applied with a significance level of 95 %. Results: No statistically significant relationship was found (p = 0.30) between theoretical knowledge of radiological protection and diagnostic imaging with respect to compliance with the norms that regulate its application (p > 0.05). Ninety percent of participants have fair to excellent knowledge. However, only 32 % comply with the technical norms of ionizing radiation protection in their clinical practice. Conclusion: Dental students have sufficient knowledge of radiation protection and diagnostic imaging. However, this knowledge is not reflected in practices that adhere to the standards.
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HumansABSTRACT
Breast cancer mortality rate is fifth among all cancer and increasing day by day due to modern lifestyles. Its molecular subtype is classified as per their significant receptor expression, such as estrogen receptor (ER), progesterone receptor (PR) & human epidermal growth receptor 2 (Her2). Triple-negative breast cancer (TNBC) is an aggressive subgroup among breast cancer subtypes and clinically challenging to treat due to loss of all three receptor (ER/PR/Her2) expression. Treatment modalities of TNBC include surgery, chemotherapy, radiotherapy and immunotherapy. Postoperative radiation therapy (RT) improves locoregional control and overall survival in TNBC patients. The powerful ionizing radiation (IR) response to RT is contributed by the inherent radiosensitivity of the tumor, which is influenced by genes associated with the cell cycle, DNA damage repair, apoptosis, etc. This review article narrates the role of biomarkers obtained through data mining and manual curation of published literature to predict radioresistance in patients receiving radiotherapy. Further, the role of natural radiosensitizers in overcoming radioresistance for effectively managing TNBC is also discussed.
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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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@#<b>Objective</b> To investigate the synergistic protective effects of WR-2721 combined with lentinan and cytokines against radiation damage in mice, and to provide a new treatment for acute radiation injury. <b>Methods</b> Seventy Institute of Cancer Research mice were divided into seven groups: a control group, a model group, WR-2721 group, Lentinan & cytokine group, WR-2721 & Lentinan group, WR-2721 & cytokine group and WR-2721 & Lentinan & cytokine group. All groups except the control group were irradiated with <sup>60</sup>Co γ-rays at a dose rate of 0.8 Gy/min and a cumulative dose of 5.0 Gy. The mice were sacrificed by cervical dislocation 14 d after irradiation to measure their spleen index, thymus index, and serum levels of superoxide dismutase (SOD), malondialdehyde (MDA), interleukin-11 (IL-11), and tumor necrosis factor-alpha (TNF-α). <b>Results</b> For the mice treated with WR-2721, lentinan, and cytokines, the spleen index was 7.33 ± 2.84, the thymus index was 1.70 ± 0.30, the serum SOD level was 114.0 ± 8.3, the MDA level was 7.33 ± 1.16, the IL-11 level was 155.8 ± 49.4, and the TNF-α level was 174.0 ± 37.8. All these indicators except the spleen index in the combination group significantly differed from those of the model group (<i>P</i> < 0.05 or 0.01), indicating the combined treatment promoted recovery from radiation damage. <b>Conclusion</b> WR-2721 combined with lentinan and cytokines has significant synergistic protective effects, which is a promising treatment for acute radiation injury.
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@#The rapid advances in technology and medicine have greatly facilitated the application of ionizing radiation. Clinically, radiotherapy is one of the major treatments for malignant tumors. However, besides killing tumor cells, ionizing radiation inevitably leads to radiation damage and even death of normal cells. How ionizing radiation causes cell death and the forms of cell death have always been important research topics in this field. Recently, several forms of cell death induced by irradiation have been discovered. Apart from apoptosis, pyroptosis, necroptosis, ferroptosis, autophagic cell death, and methuosis have gradually become research hotspots, and provide new targets for the development of radioprotective drugs and radiosensitizers. In this review, we summarize various forms of ionizing radiation-induced cell death and related molecular mechanisms. We also introduce the latest progress in radiation protection and radiosensitization based on these cell death mechanisms. This review will provide a reference for the research and development of radioprotective drugs and radiosensitizers in the future.
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Objective@# To investigate the thyroid functions and influencing factors among radiation workers in Wuhan City, so as to provide insights into occupational health monitoring among radiation workers.@*Methods @#Radiation workers receiving physical examinations in Wuhan Prevention and Treatment Center for Occupational Diseases from January to October 2022 were enrolled, and participants' gender, age, smoking, alcohol consumption, medical history, medication use, types of occupational radiation and work duration were collected. Triiodothyronine (TT3), thyroxine (TT4), free thyroxine (FT4), free triiodothyronine (FT3) and thyroid stimulating hormone (TSH) were measured using a magnetic microparticle-based chemiluminescence immunoassay. Personnel dose equivalent was monitored using thermoluminescent dosimetry, and annual cumulative radiation dose was estimated. Factors affecting thyroid function were identified using a multivariable linear regression model.@*Results@#Totally 978 radiation workers were recruited, with a median age of 32.00 (interquartile range, 10.00) years, and including 782 men (79.96%) and 196 women (20.04%). There were 246 smokers (25.15%), 257 workers with alcohol consumption (26.28%) and 489 with a history of radiation work (50.00%). The median annual cumulative radiation dose was 0.20 (interquartile range, 0.24) mSv. The percentage of abnormal thyroid function was 14.72%. Multivariable logistic regression analysis showed that women (OR=1.925, 95%CI: 1.061-3.490), history of radiation work (OR=2.810, 95%CI: 1.119-7.057) and involving in medical application (OR=1.915, 95%CI: 1.101-3.332) were associated with abnormal thyroid function.@*Conclusions@#The percentage of abnormal thyroid function was 14.72% among radiation workers in Wuhan City. History of exposure to ionizing radiation, types of occupational radiation and gender were main factors affecting thyroid function.
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Objective To investigate the occupational health status of radiation workers in Dezhou, China, explore the effects of low-dose ionizing radiation on the health of radiation workers, and provide a basis for improving the health of radiation workers. Methods A total of 1101 radiation workers in Dezhou who underwent occupational health examination in 2021 were selected. The effects of physical examination type, type of work, sex, length of service, and age on the health status of radiation workers were compared and analyzed. Results The abnormal rates of abdominal color Doppler ultrasound and eye lens were significantly higher in pre-post radiation workers than in radiation works (P < 0.05). The abnormal rates of eye lens increased with the length of service in radiation workers (P < 0.05). The abnormal rate of abdominal color Doppler ultrasound in male workers was higher than that in female workers, while the abnormal rates of blood routine and thyroid function were higher in female workers than in male workers (P < 0.05). Conclusion The abdominal rates of color Doppler ultrasound and eye lens are relatively high among radiation workers in Dezhou. It is necessary to improve the protection awareness and strengthen the level of radiation protection, so as to ensure the occupational health of radiation workers.