电离辐射对放射工作人员细胞遗传学的影响

目的 通过对放射工作人员辐射剂量进行监测,探讨电离辐射对放射工作人员细胞遗传学的影响.方法 采用流行病学中队列研究的方法,选取唐山市内1 392名放射工作人员作为观察组,选取无射线接触史且其他条件与观察组具有可比性的143名身体健康者为对照组.分别行一般情况调查、放射剂量测量、微核检测、染色体畸变检测.结果 放射线接触组微核率和染色体畸变率均明显高于对照组.按不同工种分组,观察组微核率和染色体畸变率依照医学放射诊断组、工业探伤组、工业用放射源组、医学放免放疗组的次序呈现出一定程度的递增趋势.按不同工龄分析,＜10、10～ 20和＞20a工龄组的放射工作人员细胞微核异常率分别为10.8％、16.2％、24.8％,对照组为2.1％,差异均有统计学意义(P ＜0.05或0.01);染色体畸变异常率亦随放射工龄的增加而升高.差异均有统计学意义(P＜0.05).随着累积辐射剂量的增加,放射工作人员累积微核异常率、累积染色体畸变异常率也随之增加.结论 电离辐射对放射工作人员健康状况产生一定程度的影响,淋巴细胞微核率和染色体畸变率将会有所增高.从事不同放射工种的放射工作人员受到的辐射损伤不同,放射工作人员受到的辐射损伤与接触射线年限有关,放射工龄越长,累积电离辐射剂量越高,细胞微核率和染色体畸变率越高,其对机体造血系统的损伤越严重,细胞微核率、染色体畸变率与累积辐射剂量均具有一定程度的关联.     

Influence of ionizing radiation and conventional food processing treatments on the status of free radicals in lotus seeds: An ESR study

Electron spin resonance (ESR) spectroscopy was used to detect the free radicals that were naturally present in lotus seeds or that were formed after employing various food processing methods (e.g., irradiation, microwave roasting, pan frying, grinding or pounding) by placing small portions of lotus seed (seed coat and cotyledon) in KCl powder in ESR quartz tubes. Spectral analysis revealed the presence of an insignificant natural abundance of free radicals and showed a sharp and clear signal at g = 2.002, more prominent in seed coat. Exposure to gamma radiation (0–30 kGy, the recommended dose for quarantine purposes) resulted in a dose-dependent increase of signal intensity at g = 2.002 with the seed coat exhibiting the presence of a weak triplet (a_H = 3 mT) which can be used to authenticate irradiation treatments. Irradiated cotyledon at high doses (15 and 30 kGy) revealed significant reduction in ESR signals, attributed to an increase of free radical scavengers. Common food processing practices like microwave roasting, flame heating, grinding or pounding also generated free radicals. It is envisaged that results of the present study might be valuable for health conscious consumers who are interested in the status of free radicals in foodstuffs subjected to traditional or modern food-processing techniques.     

低剂量电离辐射对放射工作人员血液指标的影响

  目的  探讨低剂量电离辐射对放射工作人员血液指标的影响。
  方法  选取武汉市某医院从事X射线影像诊断和介入放射学的工作人员共211名作为研究对象,收集其2017年个人外照射剂量和2018年初在岗期间的职业健康检查资料。按工种将研究对象分成X射线影像诊断组（104人）和介入放射学组（107人）,采用独立样本t检验对两组人群血常规及血生化指标进行比较,采用线性回归模型分析辐射暴露剂量和血常规及生化指标的关系。
  结果  介入放射学组个人年剂量均值[（0.16±0.21）mSv]高于X射线影像诊断组[（0.09±0.07）mSv]（P < 0.01）,介入放射学组的肌酐（Cr）值[（81.00±15.43）μmol/L]高于X射线影像组[（73.18±13.31）μmol/L]（P < 0.05）,其他血液指标差异无统计学意义（P > 0.05）。多元线性回归分析发现年剂量每增加1个单位,研究对象中淋巴细胞（LYM）计数降低0.73个单位（P < 0.05）。未发现血常规和血生化其他指标与年剂量存在关联关系。
  结论  低剂量电离辐射对放射工作人员外周血淋巴细胞计数、Cr值存在一定影响。
     

电离辐射对放射工作者职业健康的影响

目的 分析放射工作者外周血象、淋巴细胞微核及染色体畸变情况,为放射工作者职业防护和健康监测提供依据。方法 对2015年、2017年和2019年连续3次接受健康检查的127名放射工作者进行淋巴细胞微核、染色体及血象分析,将其设为放射组。另外选取133名无射线接触史的医务人员设为对照组;结果 放射组中淋巴细胞微核率和染色体畸变率高于对照组,白细胞和血小板计数低于对照组,均具有统计学意义（P < 0.05）。127名放射工作者外周血白细胞总数随着接触电离辐射时间的增长逐渐降低,染色体畸变率逐渐增加,均具有统计学意义（P < 0.05）。损害工龄大于20年的放射工作者染色体畸变率高于低工龄组,不同损害工龄之间比较无统计学意义（P > 0.05）。核医学与介入治疗工种染色体畸变率高于其他工种,具有统计学意义（P < 0.05）。结论 长时间接触低剂量电离辐射可使放射工作者白细胞总数降低和淋巴细胞染色体畸变率增加,应加强放射工作者防护措施以备降低电离辐射损伤程度,特别要加强核医学和介入治疗放射工作人员的职业防护。     

Estimation of yields of OH radicals in water irradiated by ionizing radiation

The yield of OH radical induced by ionizing radiation was estimated by an empirical model; a prescribed diffusion model for a spur of single size applying to neutral water. Two representative spur distances were introduced, one for an incident primary charged particle and one for a representative secondary electron, to calculate chemical yields among active species in a spur. The total yield from the track was a combination of these primary and secondary yields. Two coefficients of this combination were the parameters of the present model. Based on an optimization of these parameters by existing experimental Fricke G-values, the present model estimates the yields of OH at the microsecond timescale after an irradiation, in a unified manner from electrons to heavy ions. The predicted yields of OH around the nanosecond timescale after an irradiation may be a relevant basis for a study on the mechanisms of radiation effects. This prediction by the present model was exemplified for electrons, photons and heavy ions (proton, helium, carbon, neon, argon and iron).     

低剂量电离辐射对放射工作人员血压的影响

目的探讨低剂量电离辐射对放射工作人员血压的影响;方法选取武汉市某医院219名医务人员作为研究对象,将其中115名放射工作人员作为低剂量电离辐射暴露组,其余104名非放射工作人员作为对照组,测量两组人群的血压,同时收集暴露组的个人年剂量。采用独立样本t检验对两组人群血压进行比较,采用线性回归模型分析暴露组个人年剂量与血压的关系,采用Logistic回归分析方法,分析暴露组高血压与个人年剂量的关系;结果研究发现,暴露组血压均值明显高于对照组,差异有统计学意义(P<0.05),线性回归分析发现,暴露组个人年剂量与血压无显著关联,Logistic回归分析发现,暴露组女性患高血压的风险高于男性,个人年剂量与高血压无显著关联;结论放射工作人员中女性患高血压的风险高于男性,低剂量电离辐射与放射工作人员血压改变无显著关联。     

低剂量电离辐射对放射从业者血小板及白细胞的影响分析

目的 探讨职业低剂量电离辐射对放射从业者血小板、白细胞的影响。方法 收集2013-2015年成都市2 055名放射从业者职业健康体检的血小板及白细胞数据及从业者辐射累积暴露剂量。采用t检验、方差分析、 χ²检验、直线相关分析、协方差分析及多因素logistic回归方法进行分析。结果 协方差分析显示,随着累积暴露剂量增加,血小板、白细胞数呈降低趋势。多因素logistic回归分析显示,中等剂量及以上剂量暴露组（>4.333 mSv）随着BMI水平增加,血小板降低的风险增加愈明显（趋势检验P<0.05）;高剂量（>15.639 mSv）暴露合并吸烟是血小板降低的危险因素（OR=2.33,95%CI：1.23～4.44）。低剂量（≤4.332 mSv）暴露合并锻炼>1次/周是血小板降低的保护因素（OR=0.26,95%CI：0.09～0.70）。 结论 随着辐射累积暴露剂量增高,从业者血小板、白细胞数呈现减少的趋势,若合并超重/肥胖、吸烟则血小板减少的风险越高,而加强体育锻炼可能是白细胞减少的保护因素。     

低剂量电离辐射对放射工作人员甲状腺功能的影响

选取从事石油测井和工业探伤的455名放射工作人员作为研究对象,对其职业接触情况和甲状腺功能指标进行分析.结果显示,石油测井工作人员的年龄、放射工龄、年有效辐射剂量均高于工业探伤工作人员;不同工龄、剂量、工种间游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、促甲状腺激素(TSH)水平和异常率差异均无统计学意义;F...     

Effect of sunitinib combined with ionizing radiation on endothelial cells

The aims of present study were to evaluate the efficacy of combining sunitinib with ionizing radiation (IR) on endothelial cells in vitro and in vivo. Human umbilical vein endothelial cells (HUVECs) were exposed to IR with or without sunitinib pretreatment. Apoptosis assay and cell cycle distribution were analyzed by flow cytometry. Clonogenic survival assay at 3 Gy dose with or without sunitinib was performed. The activity of phosphatidylinositol 3-kinase (PI3K)/Akt signal pathway was detected by Western immunoblot. Lewis lung carcinoma mouse model was built to examine the effect of combination therapy on endothelial cells in vivo. Microvasculature changes were detected by immunohistochemistry using anti-CD31 antibody. Our results showed combination therapy of sunitinib and IR significantly increased apoptosis of endothelial cells and inhibited colony formation compared to sunitinib or radiotherapy alone. It also resulted in cell cycle redistribution (decreasing cells in S phase and increasing cells in G2/M phase). The activity of PI3K/Akt signal pathway was inhibited, which could be the potential mechanisms that account for the enhanced radiation response induced by sunitinib. In vivo analysis showed that combination therapy significantly decreased microvasculature formation. The results demonstrated that combination therapy of sunitinib and IR has the potential to increase the cytotoxic effects on endothelial cells.     

Effects of ionizing radiation on proliferation and differentiation of mouse induced pluripotent stem cells

The present study aimed to estimate the clonogenic and differentiation potential of induced pluripotent stem (iPS) cells exposed to ionizing radiation. Compared with mouse hematopoietic stem/progenitor cells, iPS cells were less sensitive to radiation. To examine the effect of ionizing radiation on the early differentiation pathway of iPS cells, we assessed embryoid body (EB) formation. Although EB formation was observed at all radiation doses, EB diameter decreased in a radiation dose-dependent manner. At the same time, we analyzed the expression of genes specific to differentiation in the initial iPS cells and cells of EB. The expression of the endoderm marker Afp increased remarkably in cells of EB derived from non-irradiated iPS cells; however, in irradiated cells, this expression significantly decreased in a radiation dose-dependent manner. Further, the expressions of the pluripotent stem cell markers Nanog and Oct-4 and the early mesoderm marker Brachyury significantly decreased. The results of the present study suggest that radiosensitivity with regard to gene expression differs at various stages in the early differentiation pathways of iPS cells that lead to the formation of the 3 germ layers; the sensitivity is the highest in the genes expressed during the differentiation pathways of iPS cells, leading to the formation of the endoderm.     

Effects of ionizing radiation on differentiation of murine bone marrow cells into mast cells

Mast cells, immune effector cells produced from bone marrow cells, play a major role in immunoglobulin E–mediated allergic responses. Ionizing radiation affects the functions of mast cells, which are involved in radiation-induced tissue damage. However, whether ionizing radiation affects the differential induction of mast cells is unknown. Here we investigated whether bone marrow cells of X-irradiated mice differentiated into mast cells. To induce mast cells, bone marrow cells from X-irradiated and unirradiated mice were cultured in the presence of cytokines required for mast cell induction. Although irradiation at 0.5 Gy and 2 Gy decreased the number of bone marrow cells 1 day post-irradiation, the cultured bone marrow cells of X-irradiated and unirradiated mice both expressed mast cell–related cell-surface antigens. However, the percentage of mast cells in the irradiated group was lower than in the unirradiated group. Similar decreases in the percentage of mast cells induced in the presence of X-irradiation were observed 10 days post irradiation, although the number of bone marrow cells in irradiated mice had recovered by this time. Analysis of mast cell function showed that degranulation of mast cells after immunoglobulin E–mediated allergen recognition was significantly higher in the X-irradiated group compared with in the unirradiated group. In conclusion, bone marrow cells of X-irradiated mice differentiated into mast cells, but ionizing radiation affected the differentiation efficiency and function of mast cells.     

Radioprotection of DNA by glycyrrhizic acid through scavenging free radicals

Gamma-radiation induced strand breaks in plasmid pBR322 DNA. Glycyrrhizic acid (GZA) protected plasmid DNA from radiation-induced strand breaks, as the disappearance of super-coiled (ccc) form was prevented by the compound with a dose-reduction factor of 2.04 at 2.5 mM concentration. Studies of comet assay on human peripheral blood leukocytes exposed to gamma radiation in the presence and absence of glycyrrhizic acid ex vivo revealed that this compound protected the cellular DNA from radiation-induced strand breaks in a concentration-dependent manner. An intraperitoneal administration of the GZA to mice one hour before exposure to gamma radiation protected cellular DNA from radiation-induced strand breaks in peripheral blood leucocytes and bone marrow cells, as revealed by comet assay. Pulse radiolysis studies indicated that glycyrrhizic acid offered radioprotection by scavenging free radicals. The rate constants for the reaction of glycyrrhizic acid with OH* and e(aq)- are 1.2 x 10(10 ) M(-1) s(-1) and 3.9 x 10(9 ) M(-1) s(-1), respectively.     

Effect of age on the sensitivity of the rat thyroid gland to ionizing radiation

Exposure to ionizing radiation during childhood is a well-known risk factor for thyroid cancer. Our study evaluated the effect of age on the radiosensitivity of rat thyroid glands. Four-week-old (4W), 7 -week-old (7W), and 8-month-old (8M) male Wistar rats were exposed to 8 Gy of whole-body X-ray irradiation. Thyroids were removed 3–72 h after irradiation, and non-irradiated thyroids served as controls. Ki67-positivity and p53 binding protein 1 (53BP1) focus formation (a DNA damage response) were evaluated via immunohistochemistry. Amounts of proteins involved in DNA damage response (p53, p53 phosphorylated at serine 15, p21), apoptosis (cleaved caspase-3), and autophagy (LC3, p62) were determined via western blotting. mRNA levels of 84 key autophagy-related genes were quantified using polymerase chain reaction arrays. Ki67-positive cells in 4W (with high proliferative activity) and 7W thyroids significantly decreased in number post-irradiation. The number of 53BP1 foci and amount of p53 phosphorylated at serine 15 increased 3 h after irradiation, regardless of age. No increase in apoptosis or in the levels of p53, p21 or cleaved caspase-3 was detected for any ages. Levels of LC3-II and p62 increased in irradiated 4W but not 8M thyroids, whereas expression of several autophagy-related genes was higher in 4W than 8M irradiated thyroids. Irradiation increased the expression of genes encoding pro-apoptotic proteins in both 4W and 8M thyroids. In summary, no apoptosis or p53 accumulation was noted, despite the expression of some pro-apoptotic genes in immature and adult thyroids. Irradiation induced autophagy in immature, but not in adult, rat thyroids.     

低剂量电离辐射对放射工作人员细胞遗传学影响

目的 分析低剂量电离辐射对放射工作人员细胞遗传学影响.方法 采用放射场所辐射剂量、个人剂量、细胞遗传学指标检测及流行病学横断面调查研究方法.结果 射线接触组染色体畸变率(0.16%)高于对照组(0.04%),染色体畸变检出率(17.05%)高于对照组(5.1%),微核率(1.03‰)高于对照组(0.2‰),微核检出率(48.06%)高于对照组(12.25%),差异均有统计学意义(χ²=8.45,P<0.01;χ²=7.59,P<0.01;χ²=57.23,P<0.01;χ²=32.52,P<0.01);不同年剂量、累积剂量组染色体畸变率、微核率与对照组比较,差异均有统计学意义;随着个人年剂量、累积剂量水平的增加,染色体畸变率、微核率、微核阳性检出率有增高趋势.结论 长期低剂量电离辐射,对淋巴细胞产生的辐射效应导致的染色体畸变率、微核率的增加并与放射人员个人累积吸收剂量密切相关.     

Effect of ethanol-generated free radicals on gastric intrinsic factor and glutathione

The oxidation of acetaldehyde (generated from the metabolism of ethanol) by oxidases such as xanthine oxidase generates free radicals which can mobilize ferritin iron, alter hepatic glutathione and produce lipid peroxidation. The stomach, a site of ethanol metabolism and rich in xanthine oxidase, was studied with respect to the effects of ethanol on intrinsic factor (IF) binding of vitamin B-12 as well as gastric glutathione (GSH). Incubations of gastric homogenates with acetaldehyde-xanthine oxidase inhibited the B-12 binding ability by IF. A large acute dose of ethanol in vivo (5 g/kg, conc. greater than 40% w/v) decreased gastric IF binding of B-12 and depressed gastric GSH; these effects were markedly attenuated by the feeding of sodium tungstate which inhibited xanthine oxidase. Changes in B-12 binding paralleled changes in gastric GSH. Scatchard plots of IF binding of B-12 for homogenates suggested decreased number of binding sites rather than altered affinity. In conclusion, the gastric metabolism of ethanol generates free radicals which alter IF binding of B-12, depress gastric GSH and may play a role in alcohol-induced gastric injury.     

Effect of ionizing tritium radiation in hermetically closed air on the removal of condensation nuclei

On the model of hermetically closed, tritium-ionized air of a room, not infiltrated by atmospheric air, i.e., in conditions when aerosol removal is not masked by homogeneous nucleation of condensation nuclei (CN), the processes of CN coagulation, gravitational sedimentation, and electric impaction are studied experimentally in their dependence on ionizing radiation and grounding of the container walls.The CN concentration half-time is found to decrease (even down to one-fifth) as the ionizing radiation intensity is raised from 0 to 719 mCi. In the initial stages of CN removal, coagulation predominates, whereas the subsequent stages are predominantly determined by electric impaction. The influence of those phenomena on the hygienic and sanitary conditions of the air of rooms is discussed.