超大剂量6MeV电子束照射对大鼠脑Ca2+、Mg2+含量的影响

观察超大剂量6 MeV电子束照射对大鼠脑Ca2+、Mg2+含量的动态变化,探讨其在放射性脑损伤发病机制中的作用.对SD大鼠用6MeV电子线进行10Gy、20Gy和30Gy全脑单次照射,应用等离子直读光谱仪定量分析大鼠脑放射性损伤后不同时间、不同剂量脑组织中Ca2+、Mg2+含量的动态变化,用干-湿重法测定脑组织含水量.大鼠全脑受照射后,均存在脑组织中Ca2+含量升高、Mg2+含量下降和脑水肿的发生.其中20 Gy照射后24 h脑组织中Ca2+含量与对照组相比有显著升高(p＜0.05),Mg2+含量在照后7天与对照组相比有显著下降(p＜0.05).在照后7天,上述各指标变化的幅度为30Gy组＞20Gy组＞10Gy组.基于大鼠放射性脑损伤后脑组织中Ca2+、Mg2+含量发生的变化,探讨了电离辐射所致脑损伤的机理.     

电离辐射对大鼠脑组织中稀醇化酶、S-100蛋白表达的影响

观察了超大剂量6MeV电子线照射后大鼠脑组织NSE、S-100蛋白的动态变化.对成熟的(Sprague-dawle,SD)大鼠用6MeV电子线进行10Gy、20Gy和30Gy全脑单次照射,应用免疫组织化学法测定大鼠脑损伤后不同时间、不同剂量脑组织中稀醇化酶(Neuro-specific enolase,NSE)、S-100蛋白的相对含量.60只大鼠随机分为对照组和实验组,用6MeV电子线对实验组大鼠进行20Gy全脑单次垂直照射,分别于照射后1d、7 d、14 d和30 d处死大鼠,取其脑组织,用免疫组织化学法测定NSE、S-100蛋白的相对含量,并与对照组进行比较.在上述时间点,脑内海马区S-100和NSE表达有时间规律,照射后7 dS-100蛋白的表达和照射后24h NSE的表达组间存在一定差别.与对照组相比,实验组大鼠脑组织中NSE表达显著下降(p＜0.05),S-100表达显著升高(p＜0.05).在照射后7 d,上述各指标变化的幅度为30Gy组＞20Gy组＞10Gy组.电离辐射可诱导脑组织中S-100蛋白的表达,同时下调NSE在神经元中的表达,脑组织中S-100和NSE表达水平的变化可作为辐射诱导的急性脑损伤的敏感指标.     

MgSO_4对大鼠急性放射性脑损伤后脑细胞内Ca~(2+)及脑组织NO含量的影响

为探讨硫酸镁(MgSO4)对电离辐射诱发脑损伤的保护作用,将成熟的SD大鼠36只随机分为空白对照组、实验对照组和硫酸镁实验用药组,用6 MeV电子束对实验组大鼠进行20 Gy全脑单次垂直照射,吸收剂量率为200 cGy/min;实验用药组大鼠于照射前1 d、照射后即刻和照射后连续5 d分别给予10%的MgSO4腹腔注射,分别于照后第3、10、17和24 d解剖大鼠,取其脑组织,用激光扫描共聚焦显微镜测定脑细胞内ca2+的含量,硝酸还原酶法测定脑组织一氧化氮(NO)含量.结果显示,与空白对照组相比,实验对照组大鼠脑细胞内Ca2+平均荧光强度及脑组织中NO含量明显升高(P＜0.05);与实验对照组相比,实验用药组大鼠脑细胞内Ca2+平均荧光强度及脑组织NO含量有所降低(P＜0.05).表明早期使用硫酸镁可抑制辐射引起的脑细胞内钙离子的超载及脑组织中NO含量的升高,硫酸镁对放射性脑损伤有保护作用.     

知母活性成分ZDY101对脑内定位注射鹅膏蕈氨酸拟痴呆大鼠的影响

观察中药知母活性成分ZDY101对大鼠脑内注射兴奋性氨基酸所致拟痴呆模型的治疗作用。将IBO2μg／0．5μL双侧缓慢注入SD大鼠脑基底核部,造成局部神经元变性后产生拟似痴呆症状。ZDY101分高、中、低三个剂量组连续灌胃给药90d,以避暗试验评价动物学习记忆能力,^3H-QNB单点结合法测定脑组织M受体密度。大鼠脑内注入IBO后,学习、记忆功能明显下降,脑M受体密度显著降低。给予ZDY101后,学习、记忆功能及脑M受体密度均有明显提高,且二者具有量效相关性。表明ZDY101很可能通过上调脑M受体密度而改善脑功能,是一种值得深入研究的抗老年痴呆症药物。     

在出生前以氚水照射致大鼠脑发育障碍的剂量效应关系研究

以脑组织中游离氨基酸含量为指标,观察出生前因氚水照射引起的大鼠脑发育障碍。实验用妊娠11d的大鼠经腹腔单次注入7.4×10~3—3.7×10~6Bq/ml(体水)放射性浓度的氚水。在仔鼠出生后18d将其开颅取出大脑。取一半脑组织用高效液相色谱(HPLC)测定脑组织中游离氨基酸含量。结果表明:受照仔鼠大脑组织中游离氨基酸含量随照射剂量增加而增多。在仔鼠总吸收剂量为0.0038—1.9Gy范围内,大脑组织中游离氨基酸含量增加的百分率与剂量对数值之间可拟合成直线回归方程Y=A+B lgD。     

应用质子激发X射线分析(PIXE)测定啤酒中的微量元素

一、引言营养卫生学的研究中,痕量元素日益受到人们的重视。为了保证人体对于15种必需痕量元素的补充以及保证毒性元素的摄入在允许剂量之内,从痕量元素含量角度来研究食品和饮料的质量是很重要的。PIXE提供了多种痕量元素含量的同时测定方法。啤酒中微量元素很丰富。啤酒的颜色,芳香,味道和储存质量都和所含微量元素的浓度有关。     

塞来昔布对大鼠急性放射性脑损伤的保护作用

为探讨塞来昔布对电离辐射诱发的急性脑组织损伤的脑保护作用,将成熟的SD大鼠随机分为对照组、照射组(6 MeV电子线全脑单次垂直照射,吸收剂量为10 Gy)和照射加药物组(6 MeV电子线全脑单次垂直照射,吸收剂量为10 Gy+塞来昔布30 mg/kg体重灌胃给药)。实验大鼠分别在不同时间点处死、取脑组织。应用干-湿重法测定脑组织含水量,病理切片观察大鼠脑组织形态变化,免疫组化法观察脑组织中胶质纤维酸性蛋白(GFAP)的表达。结果显示:与对照组相比,SD大鼠照射后脑组织含水量明显升高,照射加药物组大鼠各时间点脑组织含水量较照射组显著减少,差异有统计学意义(P<0.05)。全脑照射后,照射组大鼠脑组织切片呈现典型脑水肿表现,照射加药物组脑水肿程度较照射组轻。照射加药物组大鼠各时间点脑组织中GFAP阳性细胞的数量较照射组显著减少,差异有统计学意义(P<0.05),两组全脑照射后大鼠脑组织中GFAP阳性表达均较对照组明显升高。塞来昔布能有效地降低脑组织含水量,减轻脑组织水肿的程度,保护脑组织,并能减轻胶质细胞的损伤程度,起到保护神经元的作用。     

MgSO4对放射性脑损伤大鼠脑组织早期炎症反应的影响

为探讨硫酸镁对放射性脑损伤炎症反应的作用,用20Gy的电子线对SD大鼠进行全脑照射,在辐照后1、7和14d采用酶联免疫吸附法测定脑组织细胞间黏附分子（Intercellular surface adhesion molecule-1,ICAM-1）含量、分光光度法测定髓过氧化物酶（Myeloperoxidase,MPO）活性,苏木精-伊红（Hematoxylin—eosin,HE）染色法进行病理形态学观察。结果显示,放射性脑损伤大鼠脑组织中ICAM-1含量及MPO活性明显增加,引起放射性脑损伤继发性炎症反应;给予硫酸镁能显著降低放射性脑损伤大鼠的ICAM-1含量及MPO的活性,减轻炎性细胞浸润及脑组织损伤。早期给子硫酸镁可减轻放射性脑损伤大鼠脑组织的炎症效应,发挥细胞保护作用。     

仪器中子活化分析法研究脑缺血后脑中的元素含量

建立了兔局灶脑缺血模型。用仪器中子活化分析法测定了该动物模型脑组织中的锌、硒、镁、锰、钠、钾和氯的含量，并以正常兔脑组织作对照。结果表明，某些元素的含量在脑缺血后有显著变化，并随时间而变。还观察到一些元素的含量在左右两个半脑间的相关性以及钠和氯含量之间的相关性。用中药治疗脑缺血病是很有效的。将两种新的中药用于脑缺血兔，观察了它们对脑组织中元素含量的影响。     

全脑辐照后大鼠脑组织中髓鞘的变化特征

为了深入研究电离辐射后大脑组织脱髓鞘病变的发病过程,对受2、10和30Gy全脑的Sprague-Dawley大鼠,在照射后1周以及1、3和6个月时,采用酶联免疫吸附法测量脑组织中髓鞘碱性蛋白(Myelin basic protein,MBP)含量、用Luxol fast blue染色法和电镜观察并分析髓鞘的病理学改变.结果表明,2、10和30Gy照射后1周与1个月的各组大鼠,其端脑组织中MBP的含量与对照组相比均无明显差别,但10Gy和30Gy照射后3个月和6个月中MBP则有明显降低;髓鞘染色显示30Gy照射后6个月大鼠在胼胝体区有较典型的脱髓鞘病变存在,10-30Gy照射后1-6个月各组在超微结构上也有不同程度的髓鞘异常;病理学变化的严重程度与剂量、观察时间有明显的相关性.由此看来,10-30Gy照射后3-6个月的大鼠脑组织中从分子、组织形态到超微结构等方面可出现一系列的髓鞘异常改变.     

Measurement of hold-up times in a thermal ion source for metallic and monoxide ions of lanthanum and cerium

Hold-up times of ions in a thermal ion source were measured for lanthanum and cerium together with neighboring elements in the periodic table. The hold-up times of metallic and monoxide ions of both lanthanum and cerium were found to be almost the same and much longer than those of cesium, barium, praseodymium and neodymium ions. The observed long hold-up times of lanthanum and cerium ions were ascribed to long sticking times of atoms on a cavity wall.     

Toxicological study of injuries of rat’s hippocampus after lead poisoning by synchrotron microradiography and elemental mapping

The hippocampus, a major component of the brain, is one of the target nervous organs in lead poisoning. In this work, a rat’s hippocampal injury caused by lead was studied. The lead concentrations in blood, bone and hippocampus collected from rats subject to lead poisoning were quantified by Inductively Coupled Plasma Mass Spectrometry while morphological information and elemental distributions in the hippocampus were obtained with synchrotron radiation X-ray phase contrast imaging and synchrotron radiation micro-beam X-ray fluorescence, respectively. For comparison, identical characterization of the specimens from the rats in the control group was done in parallel. Results show that the ratios between the lead content in the treated group and that in the control group of the hippocampus, bone, and blood are about 2.66, 236, and 39.6, respectively. Analysis also revealed that some health elements such as S, K, Cl and P increase in the regions with high lead content in the treated hippocampus. Morphological differences between the normal and lead-exposed hippocampus specimens in some local areas were observed. Explicitly, the structure of the lead-exposed hippocampus was tortuous and irregular, and the density of the neurons in the Dentate Gyrus was significantly lower than that from the control group. The study shows that the synchrotron radiation methods are very powerful for investigating structural injury caused by heavy metals in the nervous system.     

应用中子活化分析技术测定人脑肿瘤亚细胞组分中的微量元素

采用密度梯度离心分离技术结合仪器中子活化分析技术,分析测定了人脑(正常和肿瘤)亚细胞组分中11种微量元素的浓度,并对其分布进行了讨论。     

Photoactivation of Rare Earth Elements with 20 MeV Bremsstrahlung

The oxides of scandium, yttrium and all elements from lanthanum through lutetium, except promethium, were irradiated for 1hr with bremsstrahlung γ-rays converted from a 20MeV electron beam, and the radioactive species produced as a result have been examined on the basis of photonuclear reactions, their yields, and their applicability to activation analyses. The sensitivity and selectivity of the proposed method are discussed from the data thus obtained.

The (γ,n) reaction was predominant for most elements, and at least 28 product nuclides have been identified. A number of other (γ,2n) reactions have also been observed.

The yields of the (γn) reactions have been estimated for the lanthanide rare earths through measurement of the resultant activity to be about 10⁷mole·R and somewhat more than 10% smaller for the corresponding (γ,2n) reaction. Reactions with charged particle emission contributed only a small fraction in the observed radioactivity.

Extraneous activity arising from neutron capture was also measured; these activities could be reduced considerably by encasing the sample in boron.

The lower limits of detection averaged about 1 μg for most of the rare earth elements.     

Kinetic Monte Carlo model of defect transport and irradiation effects in La-doped CeO2

A generalized Kinetic Monte Carlo code was developed to study oxygen mobility in UO₂ type nuclear fuels, using lanthanum doped CeO₂ as a surrogate material. Molecular Statics simulations were performed using interatomic potentials for CeO₂ developed by Gotte, Minervini, and Sayle to calculate local configuration-dependent oxygen vacancy migration energies. Kinetic Monte Carlo simulations of oxygen vacancy diffusion were performed at varying lanthanum dopant concentrations using the developed generalized Kinetic Monte Carlo code and the calculated configuration-dependent migration energies. All three interatomic potentials were found to confirm the lanthanum trapping effect. The results of these simulations were compared with experimental data and the Gotte potential was concluded to yield the most realistic diffusivity curve.     

Calculation of Distribution Ratios of Rare Earth Elements in Multistage Counter Current Extraction with HDEHP

Extraction of rare earth elements with di (2-ethylhexyl) phosphoric acid (HDEHP) - tributyl-phosphate (TBP)-n-paraffin system was studied as functions of concentrations of the quantity of H⁺ released into aqueous phase. The ratio of rare earth elements extracted into organic phase was found to depend on the initial composition of the aqueous solution. The ratios determined for various concentrations of rare earth elements and acid were shown as a linear function of the concentrations of acid in aqueous phase and that of rare earth elements in organic phase after extraction. The acid concentration in aqueous phase after extraction can be estimated from any initial concentrations of acid and rare earth elements in aqueous solution by this equation. Also a graphic process of experimental results could give approximate values of distribution ratio for various initial concentrations of rare earth elements and nitric acid. For calculation of the distribution ratio of each stage in multi-stage counter current extraction, a computation code was programmed on the basis of the graphical process. The calculated values agreed well with those obtained experimentally in multistage extraction.     

家兔髂骨中无机元素浓度和血清生化参量的测定

培育家兔造成骨质疏松模型,用于研究妇女骨质疏松患者骨中无机元素的变化机理,使用中子活化分析技术测定３０例家兔髂骨中无机元素含量。结果表明,实验中Ｆ元素含量较对照组显著增高,Ｍｇ元素含量显著减少,而其它元素如Ｋ、Ｎａ、Ｃａ、Ｂａ、ｍＮ、Ｓｒ在两组之无显著差异。     

Nuclear microscopy in Alzheimer’s disease

The elemental composition of the two types of brain lesions which characterise Alzheimer’s disease (AD) has been the subject of intense scrutiny over the last decade, ever since it was proposed that inorganic trace elements, particularly aluminium, might be implicated in the pathogenesis of the disease. The major evidence for this involvement was the detection of aluminium in the characteristic lesions of the AD brain; neuritic plaques and neurofibrillary tangles (NFTs). Using the powerful combination of Particle-Induced X-ray Emission (PIXE), Rutherford Backscattering Spectrometry (RBS) and Scanning Transmission Ion Microscopy (STIM), it is possible to image and analyse structures in brain sections without recourse to chemical staining. Previous results on elemental composition of senile plaques indicated the absence of aluminium at the 15 parts per million level. We have more recently focused on the analysis of neurofibrillary tangles (NFTs), destructive structural defects within neurons. Imaging and analysis of neurons in brain tissue presented a greater challenge due to the small dimensional size compared with the plaques. We describe the methodology and the results of imaging and analysing neurons in brain tissue sections using Nuclear Microscopy. Our results show that aluminium is not present in either neurons or surrounding tissue in unstained sections at the 20 ppm level, but can be observed in stained sections. We also report elemental concentrations showing significant elevations of phosphorus, sulphur, chlorine, iron and zinc.     

含服硝苯吡啶对99mTc-MIBI心肌显像的影响

为观察硝苯吡啶对＾９９ｍＴｃ－ＭＩＢＩ心肌断层显像的影响,把３５例冠心病患者分成硝苯吡啶组和硝酸甘油组,隔日行介入心肌断层显像,静注＾９９ｍＴｃ－ＭＩＢＩ后１ｈ和５ｈ时分别采集图象,分析结果显示硝苯吡啶组虽有４０．０％的心肌节段摄取较用药前改善,但１ｈ显像有３３个节段出现逆向性摄取减少,其中２９个节段５ｈ显像又恢复正常。硝酸甘油组有６９．５％心肌节段较用药前摄取改善,１ｈ显像未见有逆向性摄取减少,