Tc标记的叶酸肿瘤显像剂

叶酸受体在许多源于上皮组织的恶性肿瘤中高度表达,是目前肿瘤放射性显像研究的一个新的靶点。由于叶酸对于叶酸受体具有很高的亲和性,作为重要的特异性靶向介导分子,^99mTc标记叶酸肿瘤显像剂已成为当前放射性药物的研究热点之一。本文对不同类型的^99mTc标记的叶酸类放射性肿瘤显像剂的研究进展、应用情况和存在的问题进行了评述,探讨了^99mTc标记叶酸显像剂的一般设计方法,并对其未来发展方向进行了展望。     

CS-30加速器制备Tc的研究

本文开展了加速器制备Tc的研究,其主要工作涉及到Mo靶的制备、Mo靶的辐照、模拟辐照靶的放射化学分离和辐照靶的放射化学分离等.用D核(2H)束轰击Mo靶,辐照靶先用质量浓度为10％的NaOH溶解,再用30％的H2O2进行溶解;用Dowex-1阴离子交换柱分离纯化Tc,最后得到高纯度的含Tc的Na2TcO4溶液.     

谈谈43号元素锝(Tc)

1937年Perrier和Segre用氘核轰击钼靶得到了43号元素,它是人类历史上第一个人工合成的放射性元素,命名为锝(Technetium),外文意思是“人造的”。在现代元素周期表中,Tc却是红色标记的天然放射性元素。十九世纪中,门捷列夫发现元素周期律时,曾经预言了“锝”的存在,并且把它命名为“类锰”(eka-manganese)。他指出:“类锰”的原子量应略小于钌,大约是100;它应能     

ICP-MS法测定食品中微量~(99)Tc

针对食品样品中微量锝的检测,建立了一种高效、定量分离99Tc,并能有效除去钼、钌的方法。方法采用聚乙二醇-4000涂覆的C18-U柱分离锝、钼和钌,用2 mol/L碳酸钠溶液体系上柱后,去离子水洗脱吸附在柱上的锝。该方法对99Tc的平均回收率为100%,钼的去污因子为1.3×104,钌的去污因子为6.2×103。99Tc采用质谱法测量。方法用于食品中99Tc的检测,99Tc含量在1~20 ng/kg干样之间。     

高Tc超导体及相关化合物探索研究新进展

所有已知的层状铜氧化合物超导体结构均可按连接单元、分隔单元和三种不同的铜氧平面进行分类，由这几种基本的结构单元也可组合设计出新的结构类型，通过进一步的实验研究可以获得新结构类型的层状铜氧化合物超导体。以这一思想为出发点，本文从材料设计的角度总结了近五年来在新结构层状铜氧化合物超导体探索中的新进展。     

~(99m)Tc标记的叶酸肿瘤显像剂

叶酸受体在许多源于上皮组织的恶性肿瘤中高度表达,是目前肿瘤放射性显像研究的一个新的靶点。由于叶酸对于叶酸受体具有很高的亲合性,作为重要的特异性靶向介导分子,99mTc标记叶酸肿瘤显像剂已成为当前放射性药物的研究热点之一。本文对不同类型的99mTc标记的叶酸类放射性肿瘤显像剂的研究进展、应用情况和存在的问题进行了评述,探讨了99mTc标记叶酸显像剂的一般设计方法,并对其未来发展方向进行了展望。     

脑显像剂~（99m）Tc－ECD的制备研究

~（９９ｍ）Ｔｃ－ＥＣＤ是目前脑显像剂中一种较为理想的放射性诊断药物。本文介绍了从基本原料（Ｌ）半胱氨酸开始合成配体ＥＣＤ（Ｎ，Ｎ＇－乙撑－双－Ｌ半胱氨酸乙酯），采用锡作还原剂实现了一步法~（９９ｍ）Ｔｃ标记ＥＣＤ，并对制备的~（９９ｍ）Ｔｃ－ＥＣＤ进行了初步动物实验以评价其生物学性能。     

EPR SPECTRA OF THE HIGH Tc SUPERCONDUCTOR YBa_2Cu_3O_7

<正> INTRODUCTION. The research on a series of high T_c Y-Ba-Cu-O superconductors since its dxscovery has been found interesting. Preparations and structural studies concerning this field, as well as some spectroscopic work on the study of the superconductive mechanism have been reported. In this communication, we report the EPR studies of the superconductor YBa_2Cu_3O_7 both at room temperature and at liquid N_2 temperature.     

YBa2Cu3O7-x高Tc超导体的热转变

自朱经武等最先报道液氮温区Y—Ba—Cu—O体系超导体以来，世界上涌现第二次高Tc超导体研究热潮。材料的烧结与退火均在高温下进行，尤以退火条件对超导性能好坏影响为大。因此，高温热转变的研究对于优良材料的获得及超导机制的认识都至为重要。迄今     

Formation of Tc metal in 12 M HCl using Zn as a reductant

Amorphous TcO₂ and NH₄TcO₄ solubilized into 12 M HCl will spontaneously convert to hexachlorotechnetate (TcCl₆ ^2?). This process is accelerated upon heating but species lower than Tc(IV) are not generated by this action. TcCl₆ ^2? is kinetically unstable with regards to formation in solutions of low concentrations of HCl and will spontaneously convert back to soluble and insoluble forms of Tc(IV) in water. TcCl₆ ^2? in 12 M HCl placed in contact with the reducing metal Zn at elevated temperatures (90 °C) forms a black precipitate that contains amorphous Tc metal, TcO₂, and oxy-chlorides of Tc. Powder X-ray diffraction indicates the presence of Tc metal after thermal treatment where X-ray absorption fine structure spectroscopy indicates the presence of hexagonal Tc metal and amorphous TcO₂ in the precipitate after rinsing with 12 HCl but before thermal treatment. The resulting solution contains a mixture of Tc chlorides and oxy-chlorides following reduction where TcCl₆ ^2? is completely consumed resulting primarily in Tc₂OCl₁₀ ^4? dominating the UV–visible spectra. Reducing the solution volume and reconstituting the products into 12 M HCl while boiling the mixed solution (>24 h) will slowly convert all soluble Tc back to TcCl₆ ^2?. Expanding on previous efforts made in this laboratory to recover Tc metal from aqueous solution, we investigate its synthesis when Tc(IV) and Tc(VII) in 12 M HCl is placed in contact with the reducing metal (i.e., Zn) at elevated temperatures.     

高Tc超导体YBa2CU3Ox中铜的价态研究

应用多种光致发光光谱技术测定了高Tc超导体YBa_2Cu_3O_x的荧光光谱,对谱带的比较研究和指认表明,在这种样品中同时存在着Cu~ 、Cu~(2 )和Cu~(3 )。     

碱性条件下丁酮萃取~(99m)Tc的动力学研究

本文以恒界面池法研究了碱性条件下丁酮对99mTc的萃取动力学性质。在一定条件下,考察了萃取时间对萃取率的影响,并测定了搅拌速度、各反应物初始浓度以及温度对萃取速率的影响。实验结果表明:萃取体系在约6 h后达到平衡;搅拌速度(100-180 rpm)对萃取速率无显著影响,萃取反应的活化能为56.20(kJ/mol),萃取过程为化学反应控制模型。在碱性介质中,丁酮萃取99mTc的化学反应速率方程为:-dc(TcO4-)/dt=k c0.83(TcO4-)c1.90(CH3COC2H5),其中k=5218.85(L/L)-0.73.h-2。     

A new convenient method for the synthesis of mixed-ligand β-diketonato Tc(III) complexes

A new convenient method has been proposed to synthesize mixed-ligand -diketonato Tc(III) complexes, using the ligand exchange reaction [Tc(acac)₂(CH₃CN)₂]⁺+L^–[Tc(acac)₂L]+ +2CH₃CN where L is bza, dpm or dbm. The yield was about 30–40%. UV-visible and IR spectra of these complexes were measured. Characteristic features of the compounds were compared with those of the corresponding complexes of ruthenium.     

Study on the preparation and biological evaluation of <Superscript>99m</Superscript>Tc–gatifloxacin and <Superscript>99m</Superscript>Tc–cefepime complexes

The aim of this work is the development of new radiopharmaceuticals for imaging infection and inflammation in human. Gatifloxacin (fluoroquinolone derivative) and cefepime (cephalosporine derivative) are antibiotics used to treat bacterial infections were investigated to label with one of the most important radioactive isotopes (technetium-99m). The reaction parameters that affect the labeling yield such as substrate concentration, stannous chloride dihydrate concentration, pH of the reaction mixture, and reaction time were studied to optimize the labeling conditions. Maximum radiochemical yield of ^99mTc–gatifloxacin (90  ± 1.8%) complex was obtained by using 50 μg SnCl₂·2H₂O and 2.5 mg gatifloxacin at pH 10 while ^99mTc–cefepime was prepared at pH 8 with a maximum radiochemical yield of 98  ± 1.4% by adding ^99mTc to 5 mg cefepime in the presence of 50 μg SnCl₂·2H₂O. Biological distribution of ^99mTc–gatifloxacin and ^99mTc–cefepime was carried out in experimentally induced infection rats, in the left thigh, using Escherichia coli. Both thighs of the rats were dissected and counted and the ratio of bacterial infected thigh/contralateral thigh was then evaluated. T/NT for both ^99mTc–gatifloxacin and ^99mTc–cefepime was found to be 4.5  ± 0.3 and 8.4  ± 0.1, respectively, which was higher than that of the commercially available ^99mTc–ciprofloxacin. The abscess to normal muscle ratio indicated that ^99mTc–cefepime could be used for infection imaging. Besides, in vitro studies showed that ^99mTc–cefepime can differentiate between bacterial infection and sterile inflammation.     

高Tc YBa2Cu3O7-δ起导相生成的机理

The Y-Ba-Cu mixed oxide system is obtained when any kinds of materials containing Y, Ba, Cu are heated at 850 ℃. when heated to 900 ℃, an oxygen-rich tetragonal phase I (YBa_2Cu_3O_(6.9)) is formed. At 930 ℃, an oxygen-deficient tetragonal phase Ⅱ (YBa_2Cu_3O_6) appears, and the oxygens at positions (1/2, 0,0) and (0,1/2,0) are almost drived out. The oxygen absorbed above 650 ℃ are equally distributed onto (1/2,0,0) and (0,1/2,0), the amount of which varies with temperature. It is absorbed oxygen that migrates easily from (0, 1/2, 0) to (1/2, 0, 0) as the tetragonal phase transits into the orthorhombic phase at 650 ℃, which makes differences in oxygen-ocupancy at these two positions, such that the structure deviates from tetragonality and the superconduting properties are improved.     

Complexes of technetium(I) (Tc, Tc) pentacarbonyl core with π-acceptor ligands (tert-butyl isocyanide and triphenylphosphine): Crystal structures of [Tc(CO)5(PPh3)]OTf and [Tc(CO)5(CNC(CH3)3)]ClO4

A procedure was developed for preparing [^99mTcX(CO)₅] (X = Cl, Br, I) in a reasonable yield by high-pressure carbonylation with CO of ^99mTcO₄⁻ in aqueous solutions. In the synthesis, the substantial part of the target product is accumulated in the gas phase and can be transferred from the autoclave into various solvents when relieving the pressure. Compounds [^99mTcX(CO)₅] (X = Cl⁻, Br⁻, I⁻) are stable in solutions for several hours, but in the course of longer storage they gradually decompose to give the tricarbonyl species. Substitution of the halide ligands in [⁹⁹TcX(CO)₅] and [^99mTcX(CO)₅] with tert-butyl isocyanide and triphenylphosphine was studied. The structures of the complexes [Tc(CO)₅(PPh₃)]OTf and [Tc(CO)₅(CNC(CH₃)₃)]ClO₄ are presented.     

~(99m)Tc标记蝶呤-赖氨酸衍生物的制备及生物性能评价

基于蝶呤-赖氨酸分子结构,设计合成了2种~(99m)Tc标记配合物~(99m)Tc(HYNIC-penta-lys-Pteroyl)-(Tricine/TPPTS)和~(99m)Tc(HYNIC-Gly-Gly-lys-Pteroyl)(Tricine/TPPTS),并对其生物性能进行了初步评价.研究结果表明,2种配合物在叶酸受体高表达的人口腔表皮样癌(KB)细胞中均有很高的摄取和滞留.给药1 h后,~(99m)Tc(HYNIC-penta-lys-Pteroyl)(Tricine/TPPTS)和~(99m)Tc(HYNIC-Gly-Gly-lys-Pteroyl)(Tricine/TPPTS)在荷KB肿瘤裸鼠体内的肿瘤摄取率分别为(8.55±2.78)%ID/g和(9.77±1.54)%ID/g.荷KB肿瘤裸鼠的小动物SPECT/CT显像研究结果表明,上述2种标记配合物在给药2 h后,其肿瘤部位均清晰可见,有望作为新型的叶酸受体靶向肿瘤分子探针.