60Coγ射线对高免卵黄液中EDS-76病毒灭活的研究

用不同剂量、剂量率的^60Coγ射线对卵黄液中的EDS-76病毒进行辐照,研究了其对病毒的灭活效果和对卵黄抗体(IgY)的影响。结果表明,^60Coγ射线辐照,可以灭活高免卵黄液中的EDS-76病毒,且随辐照剂量、剂量率的增大,灭活率也增高;EDS-76病毒在卵黄液中的D10值为0．57kGy～0．60kGy;6．0kGy的辐照剂量,可以将高免卵黄液中的EDS-76病毒完全灭活,且不影响卵黄抗体效价,该卵黄抗体稳定性好、耐酸、耐热、耐蛋白酶消化。     

钴—60对高兔卵黄液中大肠杆菌的灭菌研究

用钴－60γ射线对接种于卵黄液中的大肠杆菌进行辐照灭菌,并测定了卵黄液的抗体效价、活性氧和卵黄液保存期的变化。结果表明：1.大肠杆菌在卵黄液中的D10值为0.31-0.37kGy,杀灭卵黄液中大肠杆菌的照射剂量为3kGy;2.辐照量在15kGy以下时,对卵黄液的抗体效价没有影响或仅有轻微影响;3.经8kGy照射后的卵黄液在常温、4℃、-10℃条件保存时,保存期明显长于未照射的卵黄液。     

用红外光谱法研究60CO-γ射线辐照对三斑海马粉主要成分的影响

为了考察辐照剂量对名贵中药成分的影响,本研究用红外光谱法对经剂量为0、1. 5、3、4. 5、6、9、12、15、18、19. 5和21 kGy辐照的三斑海马粉进行了研究。蛋白质是三斑海马粉的主要成分,其含量高达70%以上。结果表明,经1. 5、3、4. 5和6 kGy剂量辐照,样品的红外光谱中代表蛋白质与脂类吸收带的峰形与峰位几乎没有变化,而高于9 kGy的剂量辐照后,样品的红外光谱代表蛋白质与脂类吸收带的峰形与峰位变化较大。由此可说明,辐照剂量不超过9 kGy,辐照对样品的蛋白质二级结构影响较小;剂量高于9 kGy辐照后,辐照对样品的蛋白质二级结构影响较大。此研究结果可为核辐照企业对三斑海马粉辐照剂量的设置提供参考。     

12C6＋离子束辐照对大青叶生理生化特性的影响

利用辐射能量为100 MeV/u的12C6＋ 重离子束辐照大青叶种子,辐照剂量分别为20、40、50和80 Gy研究其对大青叶M1代的生物学效应.研究结果表明,随着辐照剂量的增大,大青叶的根系活力和叶绿素含量显著降低,发现辐照损伤主要抑制了根的生长及营养吸收;酚酸类化合物含量随着辐照剂量的增大而升高的趋势,表明辐照可提高大青叶的抗氧化和抗病虫害能力;可溶性糖、丙二醛、超氧化物歧化酶（SOD）和过氧化物酶（POD）含量变化的总体趋势为随着辐照剂量的增大先升后降.表明重离子辐照能改变大青叶的一些生理生化特征,其中40 Gy的12C6＋离子束辐照有利改善大青叶抗逆性和一些有效化学成分的积累.     

60Coγ射线对高免卵黄液中霉形体杀灭作用的研究

用^60Coγ射线处理高免卵黄液,研究了不同剂量、剂量率对霉形体的灭活效果和对卵黄抗体的影响。结果表明,^60Coγ射线可以完全杀灭高免卵黄液中的霉形体,霉形体在卵黄液中的灭活剂量为6．0kGy;10．0kGy以下的辐照剂量不影响卵黄液中蛋白质含量、pH值和活性氧自由基,同时不影响抗体效价。     

辐照对水溶液中亚硝酸盐降解效果研究

以亚硝酸盐水溶液为研究对象,研究了辐照剂量、亚硝酸盐初始浓度、Vc和NaCl含量对亚硝酸盐降解效果的影响.结果表明,辐照能有效降低水溶液中亚硝酸盐含量,亚硝酸盐降解率与辐照剂量呈正相关,与初始浓度呈负相关,Vc对辐照降解亚硝酸盐具有协同作用,NaCl对辐照降解亚硝酸盐具有抑制作用.亚硝酸盐水溶液经辐照后,硝态氮和铵态氮均有一定的增加,当辐照剂量为10.55 kGy,初始浓度为100 mg· L-1时,硝态氮含量由14.857 mg·L-1增加到17.270 mg·L-1,铵态氮含量由0.013 mg·L-1增加到0.041 mg·L-1.     

Nd：YAP激光的不同功率和时间组合对亚心形扁藻的影响

采用同一剂量不同功率和时间组合的Nd:YAP激光(波长1 341nm)辐照亚心形扁藻,辐照组分为8W 69 s、10 W 55 s和12 W 46 s三个组合,通过藻细胞生长速率和叶绿素含量测定研究激光对扁藻的影响.实验结果表明,即使同一照射剂量,不同的辐照时间与辐照功率的组合,辐照效果仍不相同,本实验中以辐照时间55 s,辐照功率10 W 为最佳组合.     

60Co-γ射线辐照毛竹种子的过氧化物同工酶和RAPD分子检测的研究

利用6种不同剂量的60Co-γ射线辐照毛竹种子,对辐照后的毛竹种子进行了过氧化物酶（POD）同工酶检测和RAPD分子检测.结果表明,过氧化物酶的活性在30 Gy和120 Gy时明显增强,其原因是毛竹在60Co-γ射线辐照胁迫下的保护效应和伤害效应.RAPD分析表明毛竹不同辐照剂量之间的DNA存在明显差异,高剂量γ 射线辐照对DNA分子的影响较大,能引起碱基序列的改变;对碱基序列差异片段测序并比对,发现部分片段与已知序列有高达83 %的同源性,部分差异片段与GeneBank中的已知序列没有较高的同源性,应该属辐照引起的DNA序列变异.同工酶和RAPD分子检测为毛竹的诱变育种参数的制定提供了理论依据.     

电子束辐照对透明质酸功能及结构特性的影响

为了探讨电子束辐照对透明质酸功能及结构特性的影响,选择5、10、20、40、80 、100和150 kGy的电子束辐照固体透明质酸,测定透明质酸辐照前后分子量、特性粘度 、pH值、抗氧化性、紫外光谱、红外光谱、电镜图片的变化.结果表明,辐照降低透明 质酸的分子量、特性粘度、pH值;透明质酸在辐照前后的吸收特征峰没有显著的改变, 吸收强度增强;透明质酸形状随着辐照剂量的升高,由块状逐渐变成颗粒状;透明质酸 对DPPH·自由基的清除作用和还原力随着辐照剂量的增大逐渐增强.电子束辐照对透明 质酸分子结构和功能有一定的影响,但对其一级结构没有影响.     

重离子辐照玉米种子引起的基因组DNA变异分析

利用HI-13串列加速器产生的10 Gy、20 Gy、30 Gy和50 Gy ~7Li和~(12)C重离子束对玉米自交系478的干种子进行辐照,并用RAPD分析技术分析其变异情况.结果表明重离子~7Li和~(12)C辐照玉米种子可引起当代基因组DNA水平上的变异,一定范围内变异频率与注入剂量有关,在相同剂量下~7Li离子辐照的诱变率高于~(12)C离子辐照.     

Differential oxidation of deoxyribose in DNA by gamma and alpha-particle radiation

Emerging evidence points to the importance of deoxyribose oxidation in the toxicity of oxidative DNA damage, including the formation of protein-DNA crosslinks and base adducts. With the goal of understanding the differences in deoxyribose oxidation chemistry known to occur with different oxidants, we have compared the formation of one product of 3'-oxidation of deoxyribose in DNA, 3'-phosphoglycolaldehyde (PGA) residues, in isolated DNA and cells exposed to ionizing radiations. A recently developed gas chromatography/negative chemical ionization mass spectrometry method was used to quantify PGA residues in purified DNA and in human TK6 lymphoblastoid cells exposed to gamma radiation (60Co) and alpha particles (241Am). The level of PGA residues was then correlated with the total quantity of deoxyribose oxidation determined by plasmid topoisomer analysis. Alpha-particle irradiation (0-100 Gy) of purified DNA in 50 mM potassium phosphate (pH 7.4) produced a linear dose response of 0.13 PGA residues per 10(6) nucleotides per gray. When normalized to an estimate of the total number of deoxyribose oxidation events (2.0 per 10(6) nucleotides per gray), PGA formation occurred in 7% (+/-0.5) of deoxyribose oxidation events produced by alpha-particle radiation. In contrast, the efficiency of PGA formation in gamma-irradiated DNA was found to be 1% (+/-0.02), which indicates a shift in the chemistry of deoxyribose oxidation, possibly as a result of the different track structures of the two types of ionizing radiation. Studies with gamma radiation were extended to TK6 cells, in which it was observed that gamma radiation produced a linear dose response of 0.0019 PGA residues per 10(6) nucleotides per gray. This is consistent with an approximately 1000-fold quenching effect in cells, similar to the results of other published studies of oxidative DNA damage in vivo.     

Adaptation of the dichlorofluorescein assay for detection of radiation-induced oxidative stress in cultured cells

The oxidation of 2'7'-dichlorofluorescin (DCFH) to 2'7'-dichlorofluorescein (DCF), a fluorescent DCFH oxidation product, is a highly sensitive indicator that is used to measure oxidative stress in cells. In the present study, a DCF assay has been adapted to quantify oxidative stress in human breast epithelial cell cultures after exposure to gamma rays. The results demonstrate that the sensitivity and specificity of the DCF assay is strongly influenced by the timing of DCFH diacetate (DCFH-DA) substrate loading in relation to radiation exposure and by the matrix in which the cells were loaded with DCFH-DA substrate. Under the conditions optimized in this study, the DCF assay is capable of detecting increased DCFH oxidation in cell cultures irradiated with gamma rays at a dose as low as 1.5 cGy. The increase in fluorescence was directly proportional to the radiation dose, which ranged from 0 to 2 Gy, and a minimal level of fluorescence was observed in sham-irradiated cells. These results indicate that the DCF assay optimized in this study is highly sensitive, linear and specific for measuring oxidative stress in irradiated cells.     

Marked difference in cytochrome c oxidation mediated by HO(*) and/or O(2)(*-) free radicals in vitro

Cytochrome c (cyt c) is an electron carrier involved in the mitochondrial respiratory chain and a critical protein in apoptosis. The oxidation of cytochrome c can therefore be relevant biologically. We studied whether cytochrome c underwent the attack of reactive oxygen species (ROS) during ionizing irradiation-induced oxidative stress. ROS were generated via water radiolysis under ionizing radiation (IR) in vitro. Characterization of oxidation was performed by mass spectrometry, after tryptic digestion, and UV-visible spectrophotometry. When both hydroxyl and superoxide free radicals were generated during water radiolysis, only five tryptic peptides of cyt c were reproducibly identified as oxidized according to a relation that was dependent of the dose of ionizing radiation. The same behavior was observed when hydroxyl free radicals were specifically generated (N(2)O-saturated solutions). Specific oxidation of cyt c by superoxide free radicals was performed and has shown that only one oxidized peptide (MIFAGIK+16), corresponding to the oxidation of Met80 into methionine sulfoxide, exhibited a radiation dose-dependent formation. In addition, the enzymatic site of cytochrome c was sensitive to the attack of both superoxide and hydroxyl radicals as observed through the reduction of Fe(3+), the degradation of the protoporphyrin IX and the oxidative disruption of the Met80-Fe(3+) bond. Noteworthy, the latter has been involved in the conversion of cyt c to a peroxidase. Finally, Met80 appears as the most sensitive residue towards hydroxyl but also superoxide free radicals mediated oxidation.     

低剂量和常规剂量螺旋CT动态扫描对慢性阻塞性肺疾病患者辐射剂量、成像质量及满意度的影响

摘要 目的：探讨低剂量和常规剂量螺旋CT动态扫描对慢性阻塞性肺疾病（COPD）患者辐射剂量、成像质量及满意度的影响。方法：选取我院于2019年1月~2020年1月收治的初步诊断为COPD的患者88例。将患者采用单双号分组法分为低剂量组和常规组,各44例。低剂量组采用低剂量螺旋CT动态扫描,常规组采用常规剂量螺旋CT动态扫描。比较两组的辐射剂量、成像质量以及COPD的诊断结果。比较两组满意度评分。结果：低剂量组CT剂量加权指数（CTDIw）、剂量长度乘积（DLP）以及有效辐射剂量（ED）均明显低于常规组,差异有统计学意义（P<0.05）。常规组成像质量的优秀率明显高于低剂量组（P<0.05）,但两组成像质量的优良率对比无明显差异（P>0.05）。低剂量组灵敏度、特异度与常规组比较差异无统计学意义（P>0.05）。低剂量组患者满意度评分明显高于常规组（P<0.05）。结论：低剂量螺旋CT动态扫描对于COPD的诊断价值与常规剂量CT动态扫描相当,且可以保证成像质量,同时其能明显降低辐射剂量、提高COPD患者满意度,具有一定的临床应用价值。     

膀胱及小肠受量对直肠癌术后放疗副反应的影响

目的:探讨直肠癌术后放疗患者膀胱平均受量及直肠受量对放射性膀胱炎及放射性肠炎的影响。方法:收集我院2005年7月至2010年12月收治的直肠癌根治术后给予放疗的患者130例,收集临床因素、病理因素、放疗因素资料,统计放疗后6个月内放射性肠炎、放射性膀胱炎发生情况。结果:放疗因素中,膀胱壁平均照射剂量对放射性肠炎及膀胱炎的发生有显著影响(P0.05),即膀胱壁剂量越高,副反应发生率越大;当膀胱壁平均剂量达到49.12 Gy时,放射性膀胱炎的发生率显著升高。小肠平均剂量控制在50 Gy以下,其值与放射性肠炎的发生无相关性。结论:直肠癌术后放疗患者膀胱壁平均受量控制在49.12 Gy以下,对减少放射性膀胱炎的发生率有意义。     

256层螺旋CT前瞻性心电门控冠状动脉成像的临床应用价值及其对比剂浓度研究

目的:探讨256层螺旋CT前瞻性心电门控冠状动脉成像的临床应用价值及不同浓度对比剂对其成像质量、碘用量以及有效辐射剂量的影响。方法:对120例疑似冠心病患者行256层螺旋CT成像扫描,将患者随机分为前瞻性心电门控组和回顾性心电门控组;出院前再将前瞻性心电门控组患者按数表法随机分为低浓度对比剂组、中浓度对比剂组和高浓度对比剂组。比较各组成像质量、碘用量、有效辐射剂量。结果:前瞻性心电门控组与回顾性心电门控组图像质量主观评分分布、可评价节段率、优良率、有效碘用量、信噪比(SNR)、载噪比(CNR)、主动脉CT值(CT主)、主动脉噪声值(SD主)比较无统计学差异(P0.05)。前瞻性心电门控组有效辐射剂量显著低于回顾性心电门控组(P0.05)。高浓度对比剂组可评价节段率、优良率、有效碘用量、SNR、CNR、CT主显著高于低浓度对比剂组和中浓度对比剂组(P0.05),中浓度对比剂组CNR显著高于低浓度对比剂组(P0.05)。结论:前瞻性心电门控技术用于冠心病诊断的图像质量与回顾性心电门控技术无明显差异,但是前瞻性心电门控技术辐射剂量更低。前瞻性心电门控使用低浓度对比剂可以获得满足临床诊断需要的图像质量,且碘用量更少。     

The effect of hypochlorite on human erythrocytes pretreated with X-radiation

Both hypochlorite and ionizing radiation induce oxidation processes of biomolecules. The effects are dependent to a large degree on the dose of the oxidizing agent. Previously we observed that split doses of gamma radiation caused lower hemolysis than the same but single doses. The critical factors influencing the occurrence of this effect were: the value of the first dose and the time between the doses. In this work we examined the effect of gamma radiation (40-400 Gy) on hemolysis of human erythrocytes induced by hypochlorite. Erythrocytes in PBS, hematocrit 2 %, were irradiated with doses of 40, 200 or 400 Gy. The dose-rate was 23.8 Gy/min. Cell suspensions were stirred during irradiation. After irradiation the erythrocytes were incubated for 1, 3 or 4 hours at room temperature and then hypochlorite was added to a 250 microM concentration. Control samples were erythrocytes treated only with NaOCl. The level of hemolysis was determined after NaOCl addition. Hemolysis of erythrocytes preirradiated with the dose of 400 Gy was lower than hemolysis of erythrocytes treated only with NaOCl. The effect was dependent on the time between the end of irradiation and the addition of NaOCl. In contrast, slightly higher hemolysis was observed for erythrocytes preirradiated with lower (40 or 200 Gy) doses of radiation. The observed effect is similar to that obtained for radiation-induced hemolysis. It suggests that ionizing radiation may induce structural and/or functional changes in erythrocytes, which make the cell more resistant to further oxidative damage.     

Comparative study of chemiluminescence and resistance of serum and its components after radiation exposure

Kinetics of spontaneous chemiluminescence (CL) and electrochemiluminescence (ECL) and resistance of blood serum and its protein, lipid and carbohydrate components under the effect of X-rays (3 to 1622 Gy) and the indirect effect of radiation initiated by the addition of hydrogen peroxide (1.5 X 10(-5)-1.5%) was studied to estimate the contribution of each of the serum components to cumulative changes in the kinetics of free radical oxidation initiated by the effect of radiation. There was a parametric dependence between the absorbed dose, the rate of ECL and the resistance of blood serum and its components. As the absorbed dose or hydrogen peroxide concentration increased ECL contribution to the cumulative luminescence signal regularly decreased. Changes in CL and ECL of blood serum induced by ionizing radiation and H2O2 were qualitatively similar. The kinetics of free radical oxidation of blood serum initiated by irradiation was determined integrally (according to CL and ECL parameters) by a complex of changes in its components.     

The Influence of Ionizing Radiation on Itraconazole in the Solid State

The aim of this study was to investigate the ionizing radiation effects, in the form of an electron beam, on itraconazole (ITR) in the solid phase. It was found that the ITR, under the influence of a standard 25 kGy dose of radiation used for the sterilization of drug substances, decomposed at 0.4%. Moreover, a gentle change of colour and a decrease in melting point does not exceed pharmacopoeial standards causing that ITR can be sterilized by radiation method. The use of high 400 kGy radiation doses resulted in a 6.5% decomposition of the ITR and eight radiodegradation products were found. However, with the exception of differential scanning calorimetry (DSC), the X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible (UV-vis) methods showed no changes in the form and the morphology of the crystals. The structures of all those compounds were investigated. It was confirmed that the ITR decomposition takes place by dehalogenation (one of Cl atom elimination), the oxidation in isobutyl residue (beside the triazole ring) and C-O bond rupture.KEY WORDS: antifungal azole, DSC, itraconazole, product radiolysis, radiation sterilization     

Long-term consequences of radiation-induced bystander effects depend on radiation quality and dose and correlate with oxidative stress

Widespread evidence indicates that exposure of cell populations to ionizing radiation results in significant biological changes in both the irradiated and nonirradiated bystander cells in the population. We investigated the role of radiation quality, or linear energy transfer (LET), and radiation dose in the propagation of stressful effects in the progeny of bystander cells. Confluent normal human cell cultures were exposed to low or high doses of 1GeV/u iron ions (LET ～ 151 keV/μm), 600 MeV/u silicon ions (LET ～ 51 keV/μm), or 1 GeV protons (LET ～ 0.2 keV/μm). Within minutes after irradiation, the cells were trypsinized and co-cultured with nonirradiated cells for 5 h. During this time, irradiated and nonirradiated cells were grown on either side of an insert with 3-μm pores. Nonirradiated cells were then harvested and allowed to grow for 20 generations. Relative to controls, the progeny of bystander cells that were co-cultured with cells irradiated with iron or silicon ions, but not protons, exhibited reduced cloning efficiency and harbored higher levels of chromosomal damage, protein oxidation and lipid peroxidation. This correlated with decreased activity of antioxidant enzymes, inactivation of the redox-sensitive metabolic enzyme aconitase, and altered translation of proteins encoded by mitochondrial DNA. Together, the results demonstrate that the long-term consequences of the induced nontargeted effects greatly depend on the quality and dose of the radiation and involve persistent oxidative stress due to induced perturbations in oxidative metabolism. They are relevant to estimates of health risks from exposures to space radiation and the emergence of second malignancies after radiotherapy.