[en] A new isonitrile ligand 3,3,5-trimethyl cyclohexylisonitrile (TMCHI) and its copper salt [Cu(TMCHI)₄BF₄] were synthesized and characterized by IR and elemental analysis. ^99mTc-TMCHI is prepared by direct labeling method with high RCP. In vitro protein binding in albumin, blood retention and biodistribution of ^99mTc-TMCHI in mice indicated that it is mainly accumulated and maintained in blood with a high protein binding rate and low washout rate. The target/non-target ratios in mice are excellent and suggest its use as a cardiac blood pool agent

[en] The effects of Tween-80 on the biodistributions in mice of ^99mTc-TBI, ^99mTc-MIBI, ^99mTcN-TBI and ^99mTcN-MIBI were reported. The studies resulted that liver and blood uptakes of Tween-80 added (TA) complexes significantly lower than that of corresponding non-Tween-80 added (NTA) complexes. And the clearance rate from blood of TA complexes faster than that of NTA complexes. The optimal concentration of Tween-80 was about 1%. It can decrease the lipophilicity of ^99mTc-complexes and improve the biological properties of the lipophilic ^99mTc-complexes for myocardial imaging. It's worthy for further studies

[en] Cyanocobalamin (CNCbl), a kind of vitamin B12 (cobalamin, Cbl), which has a special binding capability to rapid dividing cells and proliferating tissue, especially tumors, has been modified and labeled by ^99mTc. The optimal labeling condition was determined, and the biodistribution of ^99mTc-DTPA-b-CNCbl both in normal mice and TA₂ mice bearing MA891 mammary tumors were studied. ^99mTc-DTPA-b-CNCbl showed low uptake and rapid clearance in nontarget tissues, and renal excretion. About 40% of uptake at 1 hour remained in the tumor at 12 hours p.i. The satisfying ratio of T/NT was acquired at 6 hours p.i. (author)

[en] The effects of laser irradiation on high-temperature superconducting YBa₂Cu₃O_7-x thin films have been investigated by micro-Raman spectroscopy. Laser heating affects YBa₂Cu₃O_7-x thin films to varying degrees at different laser power levels. For a laser power density below 1 mW μm^-2, laser irradiation causes only thermal expansion within the focused area. When the laser power density is increased to about 1.7 mW μm^-2, oxygen out-diffusion occurs. The orthorhombic to tetragonal structural phase transition was observed at 3.1 mW μm^-2. Above 4.3 mW μm^-2, chemical decomposition is inferred from the appearance of Raman bands due to the impurity phase BaCuO₂. Comparison between the laser-heated results and the furnace-heated results was made, and the role played by temperature gradient and stress in the laser-heated sample is discussed in detail. (author)

[en] In applications of superconducting devices, the crystalline texture of high-quality YBa₂Cu₃O_7-x thin films is of primary importance. The preferred orientation of the films can be essentially controlled by means of the substrate temperature, T_s. In order to study the dependence of the film texture on different T_s, a series of films were deposited on YSZ substrates by the on-axis pulsed-laser ablation technique. The substrate temperature was varied from 600 deg. C to 800 deg. C while the rest of the growth parameters remained the same. Various analytical techniques, including x-ray diffraction, scanning electron microscopy, micro-Raman spectroscopy and the four-point probe method, were applied to characterize the films. At around T_s = 700 deg. C, the best films with the smoothest surface morphology, lowest FWHM of the rocking curve and highest in-plane texture were obtained. The resultant J_c in excess of 1x10⁶ A cm^-2 at 77 K and T_c around 91 K were also achieved at this temperature. (author)

[en] The organometallic precursor fac-[^99mTc(CO)₃(H₂O)₃]⁺ was reacted with N-ethoxy, N-ethyl dithiocarbamate (NOET) in phosphate buffered saline (pH 7.4) at room temperature for 30 minutes to produce the ^99mTc(CO)₃-NOET complex. The radiochemical purity (RCP) of the product was over 90% as measured by thin layer chromatography (TLC). No decomposition of the complex at room temperature (RT) was observed over a period of 6 hours. Its partition coefficient indicated that it was a lipophilic complex. The biodistribution comparison in mice of the ^99mTc(CO)₃-NOET complex and the ^99mTcN-NOET complex showed that the former had a lower heart and brain uptake as compared to that of the latter, suggesting the incorporation of the [^99mTc(CO)₃]⁺ core into the NOET ligand does not improve the biological features as a myocardial imaging agent. (author)

[en] Short communication

[en] In recent years, substitution of an isoelectronic Tc(V)-nitrido core [Tc≡N]²⁺ for the more common Tc(V)-oxo core[Tc=O]³⁺ has been shown to affect the chemical and biological characteristics of the resultant ^99mTc complexes and has led to the preparation of several radiotracer agents with distinct biological behavior. Lately, the preparations of ^99mTc nitrido complexes at tracer level and in sterile and pyrogen-free conditions have been extensively investigated. The application of this synthetic procedure to the preparation of Tc-99m nitrido radiopharmaceuticals with dithiocarbamates ligands, [R(R')NCS₂]^-, has led further to discover a new class of imaging agents. It was found that the biodistribution of these complexes were strongly affected by the nature of the lateral group R and R' bound to the >NCS₂ moiety. In order to extend the investigation of the biological properties of the class of technetium-99m nitrido complexes, we report here the synthesis and biodistribution of the complex ^99mTcN-BDTC as a potential brain perfusion imaging agent. It was found that the complex exhibited significant brain localization and good brain/blood ratio in mice, suggesting it could be potentially useful as a brain imaging agent. Experimental: The complex ^99mTcN-BDTC was prepared as follows: 1 ml of saline containing [^99mTcO₄]^- (15 MBq) was added to a kit containing 0.05 mg of stannous chloride dihydrate, 5.0 mg of succinic dihydrazide (SDH), 5.0 mg of propylenediamine tetraacetic acid (PDTA). The mixture was kept at room temperature for 15 min. Successively, 4.0 mg of sodium N-butyl dithiocarbamate dissolved in 1.0 ml water was added and the reaction was allowed to proceed for 10 min at room temperature. The RCP of the product was evaluated by TLC and ranged from 90%-99%. The TLC was performed on a polyamide strip and eluted with saline and CH₂Cl₂:CH₃OH=9:1(V/V) respectively. R_f values for some selected complexes were shown in Table 1, Biodistribution studies were carried out in mice in compliance with national laws related to the conduct of animal experimentation. Biological distribution results in mice for the complex were shown in Table 2. Results and discussion: From Table 2, the complex is seen to have a significant brain uptake and good brain/blood ratio. The complex also exhibited high initial myocardial uptake, but the washout from the heart was rapid. The liver uptake was significant and remained high at 60 min post-injection, suggesting the hepatobiliary system is the major route of excretion of the administered radioactivity. Conclusion: The complex ^99mTcN-BDTC was prepared through a simple and efficient method, which can be easily utilized for the preparation of a radiopharmaceutical through a freeze-dried kit formulation. The significant brain localization and high brain/blood ratio of the complex in mice were favorable properties, justifying further investigations in animals and humans.

[en] High radioactivity in liver and kidney after administration of ^99mTc-labeled antibodies is a major detriment to the use of radiolabeled antibodies for diagnosis and therapy. In the present study, the uptake mechanism of radioactivity by liver and kidney involving ^99mTc moiety was investigated. The data of in vitro and in vivo thiol transchelation studies, biodistribution alteration of ^99mTc-MAb after specific modulation of endogenous thiol containing compounds, and the finding of ^99mTc-labeled cysteine and GSH in bile, urine and kidney after administration of ^99mTc-MAb demonstrated that transchelation by thiols (cysteine and GSH) played an important role in the localization of radiotracer from ^99mTc MAb in normal tissues such as liver and kidney

[en] Aim: To study the biological properties of the myocardial imaging agent ^99mTcN(NOET)₂ and compare with ²⁰¹Tl in redistribution of ischemia myocardium. Materials and Methods: To prepared the ^99mTcN(NOET)₂ complex, the intermediate [^99mTcN]²⁺ and ligand NOET were synthesized. In the presence of reducer and the doner of N, the [^99mTc=N]²⁺ could be synthesized at 100, then NOET was added, ^99mTcN(NOET)₂ was formed at room temperature. ²⁰¹Tl was provided by the Department of Isotope, China Institute of Atomic Energy. Five dogs were from the Fu Wai experimental animal feeding center, two of them were made into ischemia myocardium models by ligating some coronary artery branches were demonstrated by X-ray coronary angiography, the extent of stenosis of those blood vessels was over 90%. Dynamic imaging of rest was performed respectively in three normal dogs after injecting a dose of 555MBq (15mCi) of ^99mTcN(NOET)₂ complex up to two hours. The whole body imaging planar and tomography imaging was carried out respectively at fixed time intervals during two hours in order to obtain the time-activity curves of heart, lung and liver, in vivo biodistribution and quality analysis of myocardial images. Moreover, intravenous blood samples were collected at different times to gain the kinetics of blood clearance. Stress and redistribution imaging underwent in two dogs with ischemia myocardium. Dipyridamol was given intravenously at a dose of 0.6mg/Kg in 4 mins. Stress :9^9mTcN(NOET)₂ myocardial SPECT imaging was performed at 30, 70 and 110 min after injection of ^99mTcN(NOET)₂ complex, stress ²⁰¹Tl myocardial SPECT imaging was carried out 10 min and redistribution imaging 4 hr after injection of 55.5MBq (1.5mCi) ²⁰¹Tl chloride. The tests of ^99mTcN(NOET)₂ and ²⁰¹Tl were performed respectively in the same dog within 10 days, in order to obtain a comparison between two myocardial redistribution imaging. Results: Radiochemical purity of ^99mTcN(NOET)₂ was 98.41%±0.46%,blood clearance T(α)_1/2=2.8±0.1min,T(β)_1/2=142.7±32.7min,Cl=292.3±117.1ml/h.Imaging studies demonstrated that ^99mTcN(NOET)₂ was distributed rapidly in the myocardium of dogs, disappearance of pulmonary uptake was faster than that of myocardium, the uptake was higher in liver. At 10,30,60,90 and 120min postinjection the myocardial uptake were 4.2±0.21, 5.3±1.48, 5.3±0.66, 4.0±0.53 and 3.67±0.35% ID; the heart-to-lung and heart-liver ratio was 1.24±0.31, 2.03±0.45, 2.33±0.31, 2.23±0.5, 2.07±0.49, and 0.94±0.008, 0.78±0.15, 0.56±0.22, 0.53±0.22, 0.38±0.15, respectively. The myocardial images were best distinct at 30 and 60 min postinjection. The redistribution of ^99mTcN(NOET)₂ in the area of ischemia myocardial was quite obvious at 60 and 120 min after injection. The result of redistribution of ^99mTcN(NOET)₂ was about same in comparison with that of ²⁰¹Tl in the same dog. Conclusion: ^99mTcN(NOET)₂ is very worth to be one of new myocardial imaging agent, it has re-distributive character just as that of ²⁰¹Tl.